mcs/gmcs/expression.cs

   1 //
   2 // expression.cs: Expression representation for the IL tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2001, 2002, 2003 Ximian, Inc.
   8 // (C) 2003, 2004 Novell, Inc.
   9 //
  10 #define USE_OLD
  11
  12 namespace Mono.CSharp {
  13         using System;
  14         using System.Collections;
  15         using System.Reflection;
  16         using System.Reflection.Emit;
  17         using System.Text;
  18
  19         /// <summary>
  20         ///   This is just a helper class, it is generated by Unary, UnaryMutator
  21         ///   when an overloaded method has been found.  It just emits the code for a
  22         ///   static call.
  23         /// </summary>
  24         public class StaticCallExpr : ExpressionStatement {
  25                 ArrayList args;
  26                 MethodInfo mi;
  27
  28                 public StaticCallExpr (MethodInfo m, ArrayList a, Location l)
  29                 {
  30                         mi = m;
  31                         args = a;
  32
  33                         type = m.ReturnType;
  34                         eclass = ExprClass.Value;
  35                         loc = l;
  36                 }
  37
  38                 public override Expression DoResolve (EmitContext ec)
  39                 {
  40                         //
  41                         // We are born fully resolved
  42                         //
  43                         return this;
  44                 }
  45
  46                 public override void Emit (EmitContext ec)
  47                 {
  48                         if (args != null)
  49                                 Invocation.EmitArguments (ec, mi, args, false, null);
  50
  51                         ec.ig.Emit (OpCodes.Call, mi);
  52                         return;
  53                 }
  54
  55                 static public StaticCallExpr MakeSimpleCall (EmitContext ec, MethodGroupExpr mg,
  56                                                          Expression e, Location loc)
  57                 {
  58                         ArrayList args;
  59                         MethodBase method;
  60
  61                         args = new ArrayList (1);
  62                         Argument a = new Argument (e, Argument.AType.Expression);
  63
  64                         // We need to resolve the arguments before sending them in !
  65                         if (!a.Resolve (ec, loc))
  66                                 return null;
  67
  68                         args.Add (a);
  69                         method = Invocation.OverloadResolve (
  70                                 ec, (MethodGroupExpr) mg, args, false, loc);
  71
  72                         if (method == null)
  73                                 return null;
  74
  75                         return new StaticCallExpr ((MethodInfo) method, args, loc);
  76                 }
  77
  78                 public override void EmitStatement (EmitContext ec)
  79                 {
  80                         Emit (ec);
  81                         if (TypeManager.TypeToCoreType (type) != TypeManager.void_type)
  82                                 ec.ig.Emit (OpCodes.Pop);
  83                 }
  84
  85                 public MethodInfo Method {
  86                         get { return mi; }
  87                 }
  88         }
  89
  90         public class ParenthesizedExpression : Expression
  91         {
  92                 public Expression Expr;
  93
  94                 public ParenthesizedExpression (Expression expr, Location loc)
  95                 {
  96                         this.Expr = expr;
  97                         this.loc = loc;
  98                 }
  99
 100                 public override Expression DoResolve (EmitContext ec)
 101                 {
 102                         Expr = Expr.Resolve (ec);
 103                         return Expr;
 104                 }
 105
 106                 public override void Emit (EmitContext ec)
 107                 {
 108                         throw new Exception ("Should not happen");
 109                 }
 110         }
 111
 112         /// <summary>
 113         ///   Unary expressions.
 114         /// </summary>
 115         ///
 116         /// <remarks>
 117         ///   Unary implements unary expressions.   It derives from
 118         ///   ExpressionStatement becuase the pre/post increment/decrement
 119         ///   operators can be used in a statement context.
 120         /// </remarks>
 121         public class Unary : Expression {
 122                 public enum Operator : byte {
 123                         UnaryPlus, UnaryNegation, LogicalNot, OnesComplement,
 124                         Indirection, AddressOf,  TOP
 125                 }
 126
 127                 public Operator Oper;
 128                 public Expression Expr;
 129
 130                 public Unary (Operator op, Expression expr, Location loc)
 131                 {
 132                         this.Oper = op;
 133                         this.Expr = expr;
 134                         this.loc = loc;
 135                 }
 136
 137                 /// <summary>
 138                 ///   Returns a stringified representation of the Operator
 139                 /// </summary>
 140                 static public string OperName (Operator oper)
 141                 {
 142                         switch (oper){
 143                         case Operator.UnaryPlus:
 144                                 return "+";
 145                         case Operator.UnaryNegation:
 146                                 return "-";
 147                         case Operator.LogicalNot:
 148                                 return "!";
 149                         case Operator.OnesComplement:
 150                                 return "~";
 151                         case Operator.AddressOf:
 152                                 return "&";
 153                         case Operator.Indirection:
 154                                 return "*";
 155                         }
 156
 157                         return oper.ToString ();
 158                 }
 159
 160                 public static readonly string [] oper_names;
 161
 162                 static Unary ()
 163                 {
 164                         oper_names = new string [(int)Operator.TOP];
 165
 166                         oper_names [(int) Operator.UnaryPlus] = "op_UnaryPlus";
 167                         oper_names [(int) Operator.UnaryNegation] = "op_UnaryNegation";
 168                         oper_names [(int) Operator.LogicalNot] = "op_LogicalNot";
 169                         oper_names [(int) Operator.OnesComplement] = "op_OnesComplement";
 170                         oper_names [(int) Operator.Indirection] = "op_Indirection";
 171                         oper_names [(int) Operator.AddressOf] = "op_AddressOf";
 172                 }
 173
 174                 void Error23 (Type t)
 175                 {
 176                         Error (
 177                                 23, "Operator " + OperName (Oper) +
 178                                 " cannot be applied to operand of type `" +
 179                                 TypeManager.CSharpName (t) + "'");
 180                 }
 181
 182                 /// <remarks>
 183                 ///   The result has been already resolved:
 184                 ///
 185                 ///   FIXME: a minus constant -128 sbyte cant be turned into a
 186                 ///   constant byte.
 187                 /// </remarks>
 188                 static Expression TryReduceNegative (Constant expr)
 189                 {
 190                         Expression e = null;
 191
 192                         if (expr is IntConstant)
 193                                 e = new IntConstant (-((IntConstant) expr).Value);
 194                         else if (expr is UIntConstant){
 195                                 uint value = ((UIntConstant) expr).Value;
 196
 197                                 if (value < 2147483649)
 198                                         return new IntConstant (-(int)value);
 199                                 else
 200                                         e = new LongConstant (-value);
 201                         }
 202                         else if (expr is LongConstant)
 203                                 e = new LongConstant (-((LongConstant) expr).Value);
 204                         else if (expr is ULongConstant){
 205                                 ulong value = ((ULongConstant) expr).Value;
 206
 207                                 if (value < 9223372036854775809)
 208                                         return new LongConstant(-(long)value);
 209                         }
 210                         else if (expr is FloatConstant)
 211                                 e = new FloatConstant (-((FloatConstant) expr).Value);
 212                         else if (expr is DoubleConstant)
 213                                 e = new DoubleConstant (-((DoubleConstant) expr).Value);
 214                         else if (expr is DecimalConstant)
 215                                 e = new DecimalConstant (-((DecimalConstant) expr).Value);
 216                         else if (expr is ShortConstant)
 217                                 e = new IntConstant (-((ShortConstant) expr).Value);
 218                         else if (expr is UShortConstant)
 219                                 e = new IntConstant (-((UShortConstant) expr).Value);
 220                         else if (expr is SByteConstant)
 221                                 e = new IntConstant (-((SByteConstant) expr).Value);
 222                         else if (expr is ByteConstant)
 223                                 e = new IntConstant (-((ByteConstant) expr).Value);
 224                         return e;
 225                 }
 226
 227                 // <summary>
 228                 //   This routine will attempt to simplify the unary expression when the
 229                 //   argument is a constant.  The result is returned in `result' and the
 230                 //   function returns true or false depending on whether a reduction
 231                 //   was performed or not
 232                 // </summary>
 233                 bool Reduce (EmitContext ec, Constant e, out Expression result)
 234                 {
 235                         Type expr_type = e.Type;
 236
 237                         switch (Oper){
 238                         case Operator.UnaryPlus:
 239                                 result = e;
 240                                 return true;
 241
 242                         case Operator.UnaryNegation:
 243                                 result = TryReduceNegative (e);
 244                                 return result != null;
 245
 246                         case Operator.LogicalNot:
 247                                 if (expr_type != TypeManager.bool_type) {
 248                                         result = null;
 249                                         Error23 (expr_type);
 250                                         return false;
 251                                 }
 252
 253                                 BoolConstant b = (BoolConstant) e;
 254                                 result = new BoolConstant (!(b.Value));
 255                                 return true;
 256
 257                         case Operator.OnesComplement:
 258                                 if (!((expr_type == TypeManager.int32_type) ||
 259                                       (expr_type == TypeManager.uint32_type) ||
 260                                       (expr_type == TypeManager.int64_type) ||
 261                                       (expr_type == TypeManager.uint64_type) ||
 262                                       (expr_type.IsSubclassOf (TypeManager.enum_type)))){
 263
 264                                         result = null;
 265                                         if (Convert.ImplicitConversionExists (ec, e, TypeManager.int32_type)){
 266                                                 result = new Cast (new TypeExpression (TypeManager.int32_type, loc), e, loc);
 267                                                 result = result.Resolve (ec);
 268                                         } else if (Convert.ImplicitConversionExists (ec, e, TypeManager.uint32_type)){
 269                                                 result = new Cast (new TypeExpression (TypeManager.uint32_type, loc), e, loc);
 270                                                 result = result.Resolve (ec);
 271                                         } else if (Convert.ImplicitConversionExists (ec, e, TypeManager.int64_type)){
 272                                                 result = new Cast (new TypeExpression (TypeManager.int64_type, loc), e, loc);
 273                                                 result = result.Resolve (ec);
 274                                         } else if (Convert.ImplicitConversionExists (ec, e, TypeManager.uint64_type)){
 275                                                 result = new Cast (new TypeExpression (TypeManager.uint64_type, loc), e, loc);
 276                                                 result = result.Resolve (ec);
 277                                         }
 278
 279                                         if (result == null || !(result is Constant)){
 280                                                 result = null;
 281                                                 Error23 (expr_type);
 282                                                 return false;
 283                                         }
 284
 285                                         expr_type = result.Type;
 286                                         e = (Constant) result;
 287                                 }
 288
 289                                 if (e is EnumConstant){
 290                                         EnumConstant enum_constant = (EnumConstant) e;
 291                                         Expression reduced;
 292
 293                                         if (Reduce (ec, enum_constant.Child, out reduced)){
 294                                                 result = new EnumConstant ((Constant) reduced, enum_constant.Type);
 295                                                 return true;
 296                                         } else {
 297                                                 result = null;
 298                                                 return false;
 299                                         }
 300                                 }
 301
 302                                 if (expr_type == TypeManager.int32_type){
 303                                         result = new IntConstant (~ ((IntConstant) e).Value);
 304                                 } else if (expr_type == TypeManager.uint32_type){
 305                                         result = new UIntConstant (~ ((UIntConstant) e).Value);
 306                                 } else if (expr_type == TypeManager.int64_type){
 307                                         result = new LongConstant (~ ((LongConstant) e).Value);
 308                                 } else if (expr_type == TypeManager.uint64_type){
 309                                         result = new ULongConstant (~ ((ULongConstant) e).Value);
 310                                 } else {
 311                                         result = null;
 312                                         Error23 (expr_type);
 313                                         return false;
 314                                 }
 315                                 return true;
 316
 317                         case Operator.AddressOf:
 318                                 result = this;
 319                                 return false;
 320
 321                         case Operator.Indirection:
 322                                 result = this;
 323                                 return false;
 324                         }
 325                         throw new Exception ("Can not constant fold: " + Oper.ToString());
 326                 }
 327
 328                 Expression ResolveOperator (EmitContext ec)
 329                 {
 330                         //
 331                         // Step 1: Default operations on CLI native types.
 332                         //
 333
 334                         // Attempt to use a constant folding operation.
 335                         if (Expr is Constant){
 336                                 Expression result;
 337
 338                                 if (Reduce (ec, (Constant) Expr, out result))
 339                                         return result;
 340                         }
 341
 342                         //
 343                         // Step 2: Perform Operator Overload location
 344                         //
 345                         Type expr_type = Expr.Type;
 346                         Expression mg;
 347                         string op_name;
 348
 349                         op_name = oper_names [(int) Oper];
 350
 351                         mg = MemberLookup (ec, expr_type, op_name, MemberTypes.Method, AllBindingFlags, loc);
 352
 353                         if (mg != null) {
 354                                 Expression e = StaticCallExpr.MakeSimpleCall (
 355                                         ec, (MethodGroupExpr) mg, Expr, loc);
 356
 357                                 if (e == null){
 358                                         Error23 (expr_type);
 359                                         return null;
 360                                 }
 361
 362                                 return e;
 363                         }
 364
 365                         // Only perform numeric promotions on:
 366                         // +, -
 367
 368                         if (expr_type == null)
 369                                 return null;
 370
 371                         switch (Oper){
 372                         case Operator.LogicalNot:
 373                                 if (expr_type != TypeManager.bool_type) {
 374                                         Expr = ResolveBoolean (ec, Expr, loc);
 375                                         if (Expr == null){
 376                                                 Error23 (expr_type);
 377                                                 return null;
 378                                         }
 379                                 }
 380
 381                                 type = TypeManager.bool_type;
 382                                 return this;
 383
 384                         case Operator.OnesComplement:
 385                                 if (!((expr_type == TypeManager.int32_type) ||
 386                                       (expr_type == TypeManager.uint32_type) ||
 387                                       (expr_type == TypeManager.int64_type) ||
 388                                       (expr_type == TypeManager.uint64_type) ||
 389                                       (expr_type.IsSubclassOf (TypeManager.enum_type)))){
 390                                         Expression e;
 391
 392                                         e = Convert.ImplicitConversion (ec, Expr, TypeManager.int32_type, loc);
 393                                         if (e != null){
 394                                                 type = TypeManager.int32_type;
 395                                                 return this;
 396                                         }
 397                                         e = Convert.ImplicitConversion (ec, Expr, TypeManager.uint32_type, loc);
 398                                         if (e != null){
 399                                                 type = TypeManager.uint32_type;
 400                                                 return this;
 401                                         }
 402                                         e = Convert.ImplicitConversion (ec, Expr, TypeManager.int64_type, loc);
 403                                         if (e != null){
 404                                                 type = TypeManager.int64_type;
 405                                                 return this;
 406                                         }
 407                                         e = Convert.ImplicitConversion (ec, Expr, TypeManager.uint64_type, loc);
 408                                         if (e != null){
 409                                                 type = TypeManager.uint64_type;
 410                                                 return this;
 411                                         }
 412                                         Error23 (expr_type);
 413                                         return null;
 414                                 }
 415                                 type = expr_type;
 416                                 return this;
 417
 418                         case Operator.AddressOf:
 419                                 if (Expr.eclass != ExprClass.Variable){
 420                                         Error (211, "Cannot take the address of non-variables");
 421                                         return null;
 422                                 }
 423
 424                                 if (!ec.InUnsafe) {
 425                                         UnsafeError (loc);
 426                                         return null;
 427                                 }
 428
 429                                 if (!TypeManager.VerifyUnManaged (Expr.Type, loc)){
 430                                         return null;
 431                                 }
 432
 433                                 IVariable variable = Expr as IVariable;
 434                                 bool is_fixed = variable != null && variable.VerifyFixed (false);
 435
 436                                 if (!ec.InFixedInitializer && !is_fixed) {
 437                                         Error (212, "You can only take the address of an unfixed expression inside " +
 438                                                "of a fixed statement initializer");
 439                                         return null;
 440                                 }
 441
 442                                 if (ec.InFixedInitializer && is_fixed) {
 443                                         Error (213, "You can not fix an already fixed expression");
 444                                         return null;
 445                                 }
 446
 447                                 LocalVariableReference lr = Expr as LocalVariableReference;
 448                                 if (lr != null){
 449                                         if (lr.local_info.IsCaptured){
 450                                                 AnonymousMethod.Error_AddressOfCapturedVar (lr.Name, loc);
 451                                                 return null;
 452                                         }
 453                                         lr.local_info.AddressTaken = true;
 454                                         lr.local_info.Used = true;
 455                                 }
 456
 457                                 // According to the specs, a variable is considered definitely assigned if you take
 458                                 // its address.
 459                                 if ((variable != null) && (variable.VariableInfo != null))
 460                                         variable.VariableInfo.SetAssigned (ec);
 461
 462                                 type = TypeManager.GetPointerType (Expr.Type);
 463                                 return this;
 464
 465                         case Operator.Indirection:
 466                                 if (!ec.InUnsafe){
 467                                         UnsafeError (loc);
 468                                         return null;
 469                                 }
 470
 471                                 if (!expr_type.IsPointer){
 472                                         Error (193, "The * or -> operator can only be applied to pointers");
 473                                         return null;
 474                                 }
 475
 476                                 //
 477                                 // We create an Indirection expression, because
 478                                 // it can implement the IMemoryLocation.
 479                                 //
 480                                 return new Indirection (Expr, loc);
 481
 482                         case Operator.UnaryPlus:
 483                                 //
 484                                 // A plus in front of something is just a no-op, so return the child.
 485                                 //
 486                                 return Expr;
 487
 488                         case Operator.UnaryNegation:
 489                                 //
 490                                 // Deals with -literals
 491                                 // int     operator- (int x)
 492                                 // long    operator- (long x)
 493                                 // float   operator- (float f)
 494                                 // double  operator- (double d)
 495                                 // decimal operator- (decimal d)
 496                                 //
 497                                 Expression expr = null;
 498
 499                                 //
 500                                 // transform - - expr into expr
 501                                 //
 502                                 if (Expr is Unary){
 503                                         Unary unary = (Unary) Expr;
 504
 505                                         if (unary.Oper == Operator.UnaryNegation)
 506                                                 return unary.Expr;
 507                                 }
 508
 509                                 //
 510                                 // perform numeric promotions to int,
 511                                 // long, double.
 512                                 //
 513                                 //
 514                                 // The following is inneficient, because we call
 515                                 // ImplicitConversion too many times.
 516                                 //
 517                                 // It is also not clear if we should convert to Float
 518                                 // or Double initially.
 519                                 //
 520                                 if (expr_type == TypeManager.uint32_type){
 521                                         //
 522                                         // FIXME: handle exception to this rule that
 523                                         // permits the int value -2147483648 (-2^31) to
 524                                         // bt wrote as a decimal interger literal
 525                                         //
 526                                         type = TypeManager.int64_type;
 527                                         Expr = Convert.ImplicitConversion (ec, Expr, type, loc);
 528                                         return this;
 529                                 }
 530
 531                                 if (expr_type == TypeManager.uint64_type){
 532                                         //
 533                                         // FIXME: Handle exception of `long value'
 534                                         // -92233720368547758087 (-2^63) to be wrote as
 535                                         // decimal integer literal.
 536                                         //
 537                                         Error23 (expr_type);
 538                                         return null;
 539                                 }
 540
 541                                 if (expr_type == TypeManager.float_type){
 542                                         type = expr_type;
 543                                         return this;
 544                                 }
 545
 546                                 expr = Convert.ImplicitConversion (ec, Expr, TypeManager.int32_type, loc);
 547                                 if (expr != null){
 548                                         Expr = expr;
 549                                         type = expr.Type;
 550                                         return this;
 551                                 }
 552
 553                                 expr = Convert.ImplicitConversion (ec, Expr, TypeManager.int64_type, loc);
 554                                 if (expr != null){
 555                                         Expr = expr;
 556                                         type = expr.Type;
 557                                         return this;
 558                                 }
 559
 560                                 expr = Convert.ImplicitConversion (ec, Expr, TypeManager.double_type, loc);
 561                                 if (expr != null){
 562                                         Expr = expr;
 563                                         type = expr.Type;
 564                                         return this;
 565                                 }
 566
 567                                 Error23 (expr_type);
 568                                 return null;
 569                         }
 570
 571                         Error (187, "No such operator '" + OperName (Oper) + "' defined for type '" +
 572                                TypeManager.CSharpName (expr_type) + "'");
 573                         return null;
 574                 }
 575
 576                 public override Expression DoResolve (EmitContext ec)
 577                 {
 578                         if (Oper == Operator.AddressOf)
 579                                 Expr = Expr.ResolveLValue (ec, new EmptyExpression ());
 580                         else
 581                                 Expr = Expr.Resolve (ec);
 582
 583                         if (Expr == null)
 584                                 return null;
 585
 586                         if (TypeManager.IsNullableType (Expr.Type))
 587                                 return new Nullable.LiftedUnaryOperator (Oper, Expr, loc).Resolve (ec);
 588
 589                         eclass = ExprClass.Value;
 590                         return ResolveOperator (ec);
 591                 }
 592
 593                 public override Expression DoResolveLValue (EmitContext ec, Expression right)
 594                 {
 595                         if (Oper == Operator.Indirection)
 596                                 return base.DoResolveLValue (ec, right);
 597
 598                         Error (131, "The left-hand side of an assignment must be a " +
 599                                "variable, property or indexer");
 600                         return null;
 601                 }
 602
 603                 public override void Emit (EmitContext ec)
 604                 {
 605                         ILGenerator ig = ec.ig;
 606
 607                         switch (Oper) {
 608                         case Operator.UnaryPlus:
 609                                 throw new Exception ("This should be caught by Resolve");
 610
 611                         case Operator.UnaryNegation:
 612                                 if (ec.CheckState) {
 613                                         ig.Emit (OpCodes.Ldc_I4_0);
 614                                         if (type == TypeManager.int64_type)
 615                                                 ig.Emit (OpCodes.Conv_U8);
 616                                         Expr.Emit (ec);
 617                                         ig.Emit (OpCodes.Sub_Ovf);
 618                                 } else {
 619                                 Expr.Emit (ec);
 620                                 ig.Emit (OpCodes.Neg);
 621                                 }
 622
 623                                 break;
 624
 625                         case Operator.LogicalNot:
 626                                 Expr.Emit (ec);
 627                                 ig.Emit (OpCodes.Ldc_I4_0);
 628                                 ig.Emit (OpCodes.Ceq);
 629                                 break;
 630
 631                         case Operator.OnesComplement:
 632                                 Expr.Emit (ec);
 633                                 ig.Emit (OpCodes.Not);
 634                                 break;
 635
 636                         case Operator.AddressOf:
 637                                 ((IMemoryLocation)Expr).AddressOf (ec, AddressOp.LoadStore);
 638                                 break;
 639
 640                         default:
 641                                 throw new Exception ("This should not happen: Operator = "
 642                                                      + Oper.ToString ());
 643                         }
 644                 }
 645
 646                 public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
 647                 {
 648                         if (Oper == Operator.LogicalNot)
 649                                 Expr.EmitBranchable (ec, target, !onTrue);
 650                         else
 651                                 base.EmitBranchable (ec, target, onTrue);
 652                 }
 653
 654                 public override string ToString ()
 655                 {
 656                         return "Unary (" + Oper + ", " + Expr + ")";
 657                 }
 658
 659         }
 660
 661         //
 662         // Unary operators are turned into Indirection expressions
 663         // after semantic analysis (this is so we can take the address
 664         // of an indirection).
 665         //
 666         public class Indirection : Expression, IMemoryLocation, IAssignMethod, IVariable {
 667                 Expression expr;
 668                 LocalTemporary temporary;
 669                 bool prepared;
 670
 671                 public Indirection (Expression expr, Location l)
 672                 {
 673                         this.expr = expr;
 674                         type = TypeManager.HasElementType (expr.Type) ? TypeManager.GetElementType (expr.Type) : expr.Type;
 675                         eclass = ExprClass.Variable;
 676                         loc = l;
 677                 }
 678
 679                 void LoadExprValue (EmitContext ec)
 680                 {
 681                 }
 682
 683                 public override void Emit (EmitContext ec)
 684                 {
 685                         if (!prepared)
 686                                 expr.Emit (ec);
 687
 688                         LoadFromPtr (ec.ig, Type);
 689                 }
 690
 691                 public void Emit (EmitContext ec, bool leave_copy)
 692                 {
 693                         Emit (ec);
 694                         if (leave_copy) {
 695                                 ec.ig.Emit (OpCodes.Dup);
 696                                 temporary = new LocalTemporary (ec, expr.Type);
 697                                 temporary.Store (ec);
 698                         }
 699                 }
 700
 701                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 702                 {
 703                         prepared = prepare_for_load;
 704
 705                         expr.Emit (ec);
 706
 707                         if (prepare_for_load)
 708                                 ec.ig.Emit (OpCodes.Dup);
 709
 710                         source.Emit (ec);
 711                         if (leave_copy) {
 712                                 ec.ig.Emit (OpCodes.Dup);
 713                                 temporary = new LocalTemporary (ec, expr.Type);
 714                                 temporary.Store (ec);
 715                         }
 716
 717                         StoreFromPtr (ec.ig, type);
 718
 719                         if (temporary != null)
 720                                 temporary.Emit (ec);
 721                 }
 722
 723                 public void AddressOf (EmitContext ec, AddressOp Mode)
 724                 {
 725                         expr.Emit (ec);
 726                 }
 727
 728                 public override Expression DoResolve (EmitContext ec)
 729                 {
 730                         //
 731                         // Born fully resolved
 732                         //
 733                         return this;
 734                 }
 735
 736                 public override string ToString ()
 737                 {
 738                         return "*(" + expr + ")";
 739                 }
 740
 741                 #region IVariable Members
 742
 743                 public VariableInfo VariableInfo {
 744                         get {
 745                                 return null;
 746                         }
 747                 }
 748
 749                 public bool VerifyFixed (bool is_expression)
 750                 {
 751                         return true;
 752                 }
 753
 754                 #endregion
 755         }
 756
 757         /// <summary>
 758         ///   Unary Mutator expressions (pre and post ++ and --)
 759         /// </summary>
 760         ///
 761         /// <remarks>
 762         ///   UnaryMutator implements ++ and -- expressions.   It derives from
 763         ///   ExpressionStatement becuase the pre/post increment/decrement
 764         ///   operators can be used in a statement context.
 765         ///
 766         /// FIXME: Idea, we could split this up in two classes, one simpler
 767         /// for the common case, and one with the extra fields for more complex
 768         /// classes (indexers require temporary access;  overloaded require method)
 769         ///
 770         /// </remarks>
 771         public class UnaryMutator : ExpressionStatement {
 772                 [Flags]
 773                 public enum Mode : byte {
 774                         IsIncrement    = 0,
 775                         IsDecrement    = 1,
 776                         IsPre          = 0,
 777                         IsPost         = 2,
 778
 779                         PreIncrement   = 0,
 780                         PreDecrement   = IsDecrement,
 781                         PostIncrement  = IsPost,
 782                         PostDecrement  = IsPost | IsDecrement
 783                 }
 784
 785                 Mode mode;
 786                 bool is_expr = false;
 787                 bool recurse = false;
 788
 789                 Expression expr;
 790
 791                 //
 792                 // This is expensive for the simplest case.
 793                 //
 794                 StaticCallExpr method;
 795
 796                 public UnaryMutator (Mode m, Expression e, Location l)
 797                 {
 798                         mode = m;
 799                         loc = l;
 800                         expr = e;
 801                 }
 802
 803                 static string OperName (Mode mode)
 804                 {
 805                         return (mode == Mode.PreIncrement || mode == Mode.PostIncrement) ?
 806                                 "++" : "--";
 807                 }
 808
 809                 void Error23 (Type t)
 810                 {
 811                         Error (
 812                                 23, "Operator " + OperName (mode) +
 813                                 " cannot be applied to operand of type `" +
 814                                 TypeManager.CSharpName (t) + "'");
 815                 }
 816
 817                 /// <summary>
 818                 ///   Returns whether an object of type `t' can be incremented
 819                 ///   or decremented with add/sub (ie, basically whether we can
 820                 ///   use pre-post incr-decr operations on it, but it is not a
 821                 ///   System.Decimal, which we require operator overloading to catch)
 822                 /// </summary>
 823                 static bool IsIncrementableNumber (Type t)
 824                 {
 825                         return (t == TypeManager.sbyte_type) ||
 826                                 (t == TypeManager.byte_type) ||
 827                                 (t == TypeManager.short_type) ||
 828                                 (t == TypeManager.ushort_type) ||
 829                                 (t == TypeManager.int32_type) ||
 830                                 (t == TypeManager.uint32_type) ||
 831                                 (t == TypeManager.int64_type) ||
 832                                 (t == TypeManager.uint64_type) ||
 833                                 (t == TypeManager.char_type) ||
 834                                 (t.IsSubclassOf (TypeManager.enum_type)) ||
 835                                 (t == TypeManager.float_type) ||
 836                                 (t == TypeManager.double_type) ||
 837                                 (t.IsPointer && t != TypeManager.void_ptr_type);
 838                 }
 839
 840                 Expression ResolveOperator (EmitContext ec)
 841                 {
 842                         Type expr_type = expr.Type;
 843
 844                         //
 845                         // Step 1: Perform Operator Overload location
 846                         //
 847                         Expression mg;
 848                         string op_name;
 849
 850                         if (mode == Mode.PreIncrement || mode == Mode.PostIncrement)
 851                                 op_name = "op_Increment";
 852                         else
 853                                 op_name = "op_Decrement";
 854
 855                         mg = MemberLookup (ec, expr_type, op_name, MemberTypes.Method, AllBindingFlags, loc);
 856
 857                         if (mg == null && expr_type.BaseType != null)
 858                                 mg = MemberLookup (ec, expr_type.BaseType, op_name,
 859                                                    MemberTypes.Method, AllBindingFlags, loc);
 860
 861                         if (mg != null) {
 862                                 method = StaticCallExpr.MakeSimpleCall (
 863                                         ec, (MethodGroupExpr) mg, expr, loc);
 864
 865                                 type = method.Type;
 866                                 return this;
 867                         }
 868
 869                         //
 870                         // The operand of the prefix/postfix increment decrement operators
 871                         // should be an expression that is classified as a variable,
 872                         // a property access or an indexer access
 873                         //
 874                         type = expr_type;
 875                         if (expr.eclass == ExprClass.Variable){
 876                                 LocalVariableReference var = expr as LocalVariableReference;
 877                                 if ((var != null) && var.IsReadOnly)
 878                                         Error (1604, "cannot assign to `" + var.Name + "' because it is readonly");
 879                                 if (IsIncrementableNumber (expr_type) ||
 880                                     expr_type == TypeManager.decimal_type){
 881                                         return this;
 882                                 }
 883                         } else if (expr.eclass == ExprClass.IndexerAccess){
 884                                 IndexerAccess ia = (IndexerAccess) expr;
 885
 886                                 expr = ia.ResolveLValue (ec, this);
 887                                 if (expr == null)
 888                                         return null;
 889
 890                                 return this;
 891                         } else if (expr.eclass == ExprClass.PropertyAccess){
 892                                 PropertyExpr pe = (PropertyExpr) expr;
 893
 894                                 if (pe.VerifyAssignable ())
 895                                         return this;
 896
 897                                 return null;
 898                         } else {
 899                                 expr.Error_UnexpectedKind ("variable, indexer or property access", loc);
 900                                 return null;
 901                         }
 902
 903                         Error (187, "No such operator '" + OperName (mode) + "' defined for type '" +
 904                                TypeManager.CSharpName (expr_type) + "'");
 905                         return null;
 906                 }
 907
 908                 public override Expression DoResolve (EmitContext ec)
 909                 {
 910                         expr = expr.Resolve (ec);
 911
 912                         if (expr == null)
 913                                 return null;
 914
 915                         eclass = ExprClass.Value;
 916
 917                         if (TypeManager.IsNullableType (expr.Type))
 918                                 return new Nullable.LiftedUnaryMutator (mode, expr, loc).Resolve (ec);
 919
 920                         return ResolveOperator (ec);
 921                 }
 922
 923                 static int PtrTypeSize (Type t)
 924                 {
 925                         return GetTypeSize (TypeManager.GetElementType (t));
 926                 }
 927
 928                 //
 929                 // Loads the proper "1" into the stack based on the type, then it emits the
 930                 // opcode for the operation requested
 931                 //
 932                 void LoadOneAndEmitOp (EmitContext ec, Type t)
 933                 {
 934                         //
 935                         // Measure if getting the typecode and using that is more/less efficient
 936                         // that comparing types.  t.GetTypeCode() is an internal call.
 937                         //
 938                         ILGenerator ig = ec.ig;
 939
 940                         if (t == TypeManager.uint64_type || t == TypeManager.int64_type)
 941                                 LongConstant.EmitLong (ig, 1);
 942                         else if (t == TypeManager.double_type)
 943                                 ig.Emit (OpCodes.Ldc_R8, 1.0);
 944                         else if (t == TypeManager.float_type)
 945                                 ig.Emit (OpCodes.Ldc_R4, 1.0F);
 946                         else if (t.IsPointer){
 947                                 int n = PtrTypeSize (t);
 948
 949                                 if (n == 0)
 950                                         ig.Emit (OpCodes.Sizeof, t);
 951                                 else
 952                                         IntConstant.EmitInt (ig, n);
 953                         } else
 954                                 ig.Emit (OpCodes.Ldc_I4_1);
 955
 956                         //
 957                         // Now emit the operation
 958                         //
 959                         if (ec.CheckState){
 960                                 if (t == TypeManager.int32_type ||
 961                                     t == TypeManager.int64_type){
 962                                         if ((mode & Mode.IsDecrement) != 0)
 963                                                 ig.Emit (OpCodes.Sub_Ovf);
 964                                         else
 965                                                 ig.Emit (OpCodes.Add_Ovf);
 966                                 } else if (t == TypeManager.uint32_type ||
 967                                            t == TypeManager.uint64_type){
 968                                         if ((mode & Mode.IsDecrement) != 0)
 969                                                 ig.Emit (OpCodes.Sub_Ovf_Un);
 970                                         else
 971                                                 ig.Emit (OpCodes.Add_Ovf_Un);
 972                                 } else {
 973                                         if ((mode & Mode.IsDecrement) != 0)
 974                                                 ig.Emit (OpCodes.Sub_Ovf);
 975                                         else
 976                                                 ig.Emit (OpCodes.Add_Ovf);
 977                                 }
 978                         } else {
 979                                 if ((mode & Mode.IsDecrement) != 0)
 980                                         ig.Emit (OpCodes.Sub);
 981                                 else
 982                                         ig.Emit (OpCodes.Add);
 983                         }
 984
 985                         if (t == TypeManager.sbyte_type){
 986                                 if (ec.CheckState)
 987                                         ig.Emit (OpCodes.Conv_Ovf_I1);
 988                                 else
 989                                         ig.Emit (OpCodes.Conv_I1);
 990                         } else if (t == TypeManager.byte_type){
 991                                 if (ec.CheckState)
 992                                         ig.Emit (OpCodes.Conv_Ovf_U1);
 993                                 else
 994                                         ig.Emit (OpCodes.Conv_U1);
 995                         } else if (t == TypeManager.short_type){
 996                                 if (ec.CheckState)
 997                                         ig.Emit (OpCodes.Conv_Ovf_I2);
 998                                 else
 999                                         ig.Emit (OpCodes.Conv_I2);
1000                         } else if (t == TypeManager.ushort_type || t == TypeManager.char_type){
1001                                 if (ec.CheckState)
1002                                         ig.Emit (OpCodes.Conv_Ovf_U2);
1003                                 else
1004                                         ig.Emit (OpCodes.Conv_U2);
1005                         }
1006
1007                 }
1008
1009                 void EmitCode (EmitContext ec, bool is_expr)
1010                 {
1011                         recurse = true;
1012                         this.is_expr = is_expr;
1013                         ((IAssignMethod) expr).EmitAssign (ec, this, is_expr && (mode == Mode.PreIncrement || mode == Mode.PreDecrement), true);
1014                 }
1015
1016                 public override void Emit (EmitContext ec)
1017                 {
1018                         //
1019                         // We use recurse to allow ourselfs to be the source
1020                         // of an assignment. This little hack prevents us from
1021                         // having to allocate another expression
1022                         //
1023                         if (recurse) {
1024                                 ((IAssignMethod) expr).Emit (ec, is_expr && (mode == Mode.PostIncrement  || mode == Mode.PostDecrement));
1025                                 if (method == null)
1026                                         LoadOneAndEmitOp (ec, expr.Type);
1027                                 else
1028                                         ec.ig.Emit (OpCodes.Call, method.Method);
1029                                 recurse = false;
1030                                 return;
1031                         }
1032
1033                         EmitCode (ec, true);
1034                 }
1035
1036                 public override void EmitStatement (EmitContext ec)
1037                 {
1038                         EmitCode (ec, false);
1039                 }
1040         }
1041
1042         /// <summary>
1043         ///   Base class for the `Is' and `As' classes.
1044         /// </summary>
1045         ///
1046         /// <remarks>
1047         ///   FIXME: Split this in two, and we get to save the `Operator' Oper
1048         ///   size.
1049         /// </remarks>
1050         public abstract class Probe : Expression {
1051                 public Expression ProbeType;
1052                 protected Expression expr;
1053                 protected Type probe_type;
1054
1055                 public Probe (Expression expr, Expression probe_type, Location l)
1056                 {
1057                         ProbeType = probe_type;
1058                         loc = l;
1059                         this.expr = expr;
1060                 }
1061
1062                 public Expression Expr {
1063                         get {
1064                                 return expr;
1065                         }
1066                 }
1067
1068                 public override Expression DoResolve (EmitContext ec)
1069                 {
1070                         TypeExpr texpr = ProbeType.ResolveAsTypeTerminal (ec);
1071                         if (texpr == null)
1072                                 return null;
1073                         probe_type = texpr.Type;
1074
1075                         CheckObsoleteAttribute (probe_type);
1076
1077                         expr = expr.Resolve (ec);
1078                         if (expr == null)
1079                                 return null;
1080
1081                         if (expr.Type.IsPointer) {
1082                                 Report.Error (244, loc, "\"is\" or \"as\" are not valid on pointer types");
1083                                 return null;
1084                         }
1085                         return this;
1086                 }
1087         }
1088
1089         /// <summary>
1090         ///   Implementation of the `is' operator.
1091         /// </summary>
1092         public class Is : Probe {
1093                 public Is (Expression expr, Expression probe_type, Location l)
1094                         : base (expr, probe_type, l)
1095                 {
1096                 }
1097
1098                 enum Action {
1099                         AlwaysTrue, AlwaysNull, AlwaysFalse, LeaveOnStack, Probe
1100                 }
1101
1102                 Action action;
1103
1104                 public override void Emit (EmitContext ec)
1105                 {
1106                         ILGenerator ig = ec.ig;
1107
1108                         expr.Emit (ec);
1109
1110                         switch (action){
1111                         case Action.AlwaysFalse:
1112                                 ig.Emit (OpCodes.Pop);
1113                                 IntConstant.EmitInt (ig, 0);
1114                                 return;
1115                         case Action.AlwaysTrue:
1116                                 ig.Emit (OpCodes.Pop);
1117                                 IntConstant.EmitInt (ig, 1);
1118                                 return;
1119                         case Action.LeaveOnStack:
1120                                 // the `e != null' rule.
1121                                 ig.Emit (OpCodes.Ldnull);
1122                                 ig.Emit (OpCodes.Ceq);
1123                                 ig.Emit (OpCodes.Ldc_I4_0);
1124                                 ig.Emit (OpCodes.Ceq);
1125                                 return;
1126                         case Action.Probe:
1127                                 ig.Emit (OpCodes.Isinst, probe_type);
1128                                 ig.Emit (OpCodes.Ldnull);
1129                                 ig.Emit (OpCodes.Cgt_Un);
1130                                 return;
1131                         }
1132                         throw new Exception ("never reached");
1133                 }
1134
1135                 public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
1136                 {
1137                         ILGenerator ig = ec.ig;
1138
1139                         switch (action){
1140                         case Action.AlwaysFalse:
1141                                 if (! onTrue)
1142                                         ig.Emit (OpCodes.Br, target);
1143
1144                                 return;
1145                         case Action.AlwaysTrue:
1146                                 if (onTrue)
1147                                         ig.Emit (OpCodes.Br, target);
1148
1149                                 return;
1150                         case Action.LeaveOnStack:
1151                                 // the `e != null' rule.
1152                                 expr.Emit (ec);
1153                                 ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
1154                                 return;
1155                         case Action.Probe:
1156                                 expr.Emit (ec);
1157                                 ig.Emit (OpCodes.Isinst, probe_type);
1158                                 ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
1159                                 return;
1160                         }
1161                         throw new Exception ("never reached");
1162                 }
1163
1164                 public override Expression DoResolve (EmitContext ec)
1165                 {
1166                         Expression e = base.DoResolve (ec);
1167
1168                         if ((e == null) || (expr == null))
1169                                 return null;
1170
1171                         Type etype = expr.Type;
1172                         bool warning_always_matches = false;
1173                         bool warning_never_matches = false;
1174
1175                         type = TypeManager.bool_type;
1176                         eclass = ExprClass.Value;
1177
1178                         //
1179                         // First case, if at compile time, there is an implicit conversion
1180                         // then e != null (objects) or true (value types)
1181                         //
1182                         e = Convert.ImplicitConversionStandard (ec, expr, probe_type, loc);
1183                         if (e != null){
1184                                 expr = e;
1185                                 if (etype.IsValueType)
1186                                         action = Action.AlwaysTrue;
1187                                 else
1188                                         action = Action.LeaveOnStack;
1189
1190                                 warning_always_matches = true;
1191                         } else if (Convert.ExplicitReferenceConversionExists (etype, probe_type)){
1192                                 if (etype.IsGenericParameter)
1193                                         expr = new BoxedCast (expr, etype);
1194
1195                                 //
1196                                 // Second case: explicit reference convresion
1197                                 //
1198                                 if (expr is NullLiteral)
1199                                         action = Action.AlwaysFalse;
1200                                 else
1201                                         action = Action.Probe;
1202                         } else {
1203                                 action = Action.AlwaysFalse;
1204                                 warning_never_matches = true;
1205                         }
1206
1207                         if (warning_always_matches)
1208                                 Warning (183, "The given expression is always of the provided ('{0}') type", TypeManager.CSharpName (probe_type));
1209                         else if (warning_never_matches){
1210                                 if (!(probe_type.IsInterface || expr.Type.IsInterface))
1211                                         Warning (184, "The given expression is never of the provided ('{0}') type", TypeManager.CSharpName (probe_type));
1212                         }
1213
1214                         return this;
1215                 }
1216         }
1217
1218         /// <summary>
1219         ///   Implementation of the `as' operator.
1220         /// </summary>
1221         public class As : Probe {
1222                 public As (Expression expr, Expression probe_type, Location l)
1223                         : base (expr, probe_type, l)
1224                 {
1225                 }
1226
1227                 bool do_isinst = false;
1228
1229                 public override void Emit (EmitContext ec)
1230                 {
1231                         ILGenerator ig = ec.ig;
1232
1233                         expr.Emit (ec);
1234
1235                         if (do_isinst)
1236                                 ig.Emit (OpCodes.Isinst, probe_type);
1237                 }
1238
1239                 static void Error_CannotConvertType (Type source, Type target, Location loc)
1240                 {
1241                         Report.Error (
1242                                 39, loc, "as operator can not convert from `" +
1243                                 TypeManager.CSharpName (source) + "' to `" +
1244                                 TypeManager.CSharpName (target) + "'");
1245                 }
1246
1247                 public override Expression DoResolve (EmitContext ec)
1248                 {
1249                         Expression e = base.DoResolve (ec);
1250
1251                         if (e == null)
1252                                 return null;
1253
1254                         type = probe_type;
1255                         eclass = ExprClass.Value;
1256                         Type etype = expr.Type;
1257
1258                         if (TypeManager.IsValueType (probe_type)){
1259                                 Report.Error (77, loc, "The as operator should be used with a reference type only (" +
1260                                               TypeManager.CSharpName (probe_type) + " is a value type)");
1261                                 return null;
1262
1263                         }
1264
1265                         e = Convert.ImplicitConversion (ec, expr, probe_type, loc);
1266                         if (e != null){
1267                                 expr = e;
1268                                 do_isinst = false;
1269                                 return this;
1270                         }
1271
1272                         if (Convert.ExplicitReferenceConversionExists (etype, probe_type)){
1273                                 if (etype.IsGenericParameter)
1274                                         expr = new BoxedCast (expr, etype);
1275
1276                                 do_isinst = true;
1277                                 return this;
1278                         }
1279
1280                         Error_CannotConvertType (etype, probe_type, loc);
1281                         return null;
1282                 }
1283         }
1284
1285         /// <summary>
1286         ///   This represents a typecast in the source language.
1287         ///
1288         ///   FIXME: Cast expressions have an unusual set of parsing
1289         ///   rules, we need to figure those out.
1290         /// </summary>
1291         public class Cast : Expression {
1292                 Expression target_type;
1293                 Expression expr;
1294
1295                 public Cast (Expression cast_type, Expression expr, Location loc)
1296                 {
1297                         this.target_type = cast_type;
1298                         this.expr = expr;
1299                         this.loc = loc;
1300                 }
1301
1302                 public Expression TargetType {
1303                         get {
1304                                 return target_type;
1305                         }
1306                 }
1307
1308                 public Expression Expr {
1309                         get {
1310                                 return expr;
1311                         }
1312                         set {
1313                                 expr = value;
1314                         }
1315                 }
1316
1317                 bool CheckRange (EmitContext ec, long value, Type type, long min, long max)
1318                 {
1319                         if (!ec.ConstantCheckState)
1320                                 return true;
1321
1322                         if ((value < min) || (value > max)) {
1323                                 Error (221, "Constant value `" + value + "' cannot be converted " +
1324                                        "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
1325                                        "syntax to override)");
1326                                 return false;
1327                         }
1328
1329                         return true;
1330                 }
1331
1332                 bool CheckRange (EmitContext ec, ulong value, Type type, ulong max)
1333                 {
1334                         if (!ec.ConstantCheckState)
1335                                 return true;
1336
1337                         if (value > max) {
1338                                 Error (221, "Constant value `" + value + "' cannot be converted " +
1339                                        "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
1340                                        "syntax to override)");
1341                                 return false;
1342                         }
1343
1344                         return true;
1345                 }
1346
1347                 bool CheckUnsigned (EmitContext ec, long value, Type type)
1348                 {
1349                         if (!ec.ConstantCheckState)
1350                                 return true;
1351
1352                         if (value < 0) {
1353                                 Error (221, "Constant value `" + value + "' cannot be converted " +
1354                                        "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
1355                                        "syntax to override)");
1356                                 return false;
1357                         }
1358
1359                         return true;
1360                 }
1361
1362                 /// <summary>
1363                 ///   Attempts to do a compile-time folding of a constant cast.
1364                 /// </summary>
1365                 Expression TryReduce (EmitContext ec, Type target_type)
1366                 {
1367                         Expression real_expr = expr;
1368                         if (real_expr is EnumConstant)
1369                                 real_expr = ((EnumConstant) real_expr).Child;
1370
1371                         if (real_expr is ByteConstant){
1372                                 byte v = ((ByteConstant) real_expr).Value;
1373
1374                                 if (target_type == TypeManager.sbyte_type) {
1375                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1376                                                 return null;
1377                                         return new SByteConstant ((sbyte) v);
1378                                 }
1379                                 if (target_type == TypeManager.short_type)
1380                                         return new ShortConstant ((short) v);
1381                                 if (target_type == TypeManager.ushort_type)
1382                                         return new UShortConstant ((ushort) v);
1383                                 if (target_type == TypeManager.int32_type)
1384                                         return new IntConstant ((int) v);
1385                                 if (target_type == TypeManager.uint32_type)
1386                                         return new UIntConstant ((uint) v);
1387                                 if (target_type == TypeManager.int64_type)
1388                                         return new LongConstant ((long) v);
1389                                 if (target_type == TypeManager.uint64_type)
1390                                         return new ULongConstant ((ulong) v);
1391                                 if (target_type == TypeManager.float_type)
1392                                         return new FloatConstant ((float) v);
1393                                 if (target_type == TypeManager.double_type)
1394                                         return new DoubleConstant ((double) v);
1395                                 if (target_type == TypeManager.char_type)
1396                                         return new CharConstant ((char) v);
1397                                 if (target_type == TypeManager.decimal_type)
1398                                         return new DecimalConstant ((decimal) v);
1399                         }
1400                         if (real_expr is SByteConstant){
1401                                 sbyte v = ((SByteConstant) real_expr).Value;
1402
1403                                 if (target_type == TypeManager.byte_type) {
1404                                         if (!CheckUnsigned (ec, v, target_type))
1405                                                 return null;
1406                                         return new ByteConstant ((byte) v);
1407                                 }
1408                                 if (target_type == TypeManager.short_type)
1409                                         return new ShortConstant ((short) v);
1410                                 if (target_type == TypeManager.ushort_type) {
1411                                         if (!CheckUnsigned (ec, v, target_type))
1412                                                 return null;
1413                                         return new UShortConstant ((ushort) v);
1414                                 } if (target_type == TypeManager.int32_type)
1415                                         return new IntConstant ((int) v);
1416                                 if (target_type == TypeManager.uint32_type) {
1417                                         if (!CheckUnsigned (ec, v, target_type))
1418                                                 return null;
1419                                         return new UIntConstant ((uint) v);
1420                                 } if (target_type == TypeManager.int64_type)
1421                                         return new LongConstant ((long) v);
1422                                 if (target_type == TypeManager.uint64_type) {
1423                                         if (!CheckUnsigned (ec, v, target_type))
1424                                                 return null;
1425                                         return new ULongConstant ((ulong) v);
1426                                 }
1427                                 if (target_type == TypeManager.float_type)
1428                                         return new FloatConstant ((float) v);
1429                                 if (target_type == TypeManager.double_type)
1430                                         return new DoubleConstant ((double) v);
1431                                 if (target_type == TypeManager.char_type) {
1432                                         if (!CheckUnsigned (ec, v, target_type))
1433                                                 return null;
1434                                         return new CharConstant ((char) v);
1435                                 }
1436                                 if (target_type == TypeManager.decimal_type)
1437                                         return new DecimalConstant ((decimal) v);
1438                         }
1439                         if (real_expr is ShortConstant){
1440                                 short v = ((ShortConstant) real_expr).Value;
1441
1442                                 if (target_type == TypeManager.byte_type) {
1443                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1444                                                 return null;
1445                                         return new ByteConstant ((byte) v);
1446                                 }
1447                                 if (target_type == TypeManager.sbyte_type) {
1448                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1449                                                 return null;
1450                                         return new SByteConstant ((sbyte) v);
1451                                 }
1452                                 if (target_type == TypeManager.ushort_type) {
1453                                         if (!CheckUnsigned (ec, v, target_type))
1454                                                 return null;
1455                                         return new UShortConstant ((ushort) v);
1456                                 }
1457                                 if (target_type == TypeManager.int32_type)
1458                                         return new IntConstant ((int) v);
1459                                 if (target_type == TypeManager.uint32_type) {
1460                                         if (!CheckUnsigned (ec, v, target_type))
1461                                                 return null;
1462                                         return new UIntConstant ((uint) v);
1463                                 }
1464                                 if (target_type == TypeManager.int64_type)
1465                                         return new LongConstant ((long) v);
1466                                 if (target_type == TypeManager.uint64_type) {
1467                                         if (!CheckUnsigned (ec, v, target_type))
1468                                                 return null;
1469                                         return new ULongConstant ((ulong) v);
1470                                 }
1471                                 if (target_type == TypeManager.float_type)
1472                                         return new FloatConstant ((float) v);
1473                                 if (target_type == TypeManager.double_type)
1474                                         return new DoubleConstant ((double) v);
1475                                 if (target_type == TypeManager.char_type) {
1476                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1477                                                 return null;
1478                                         return new CharConstant ((char) v);
1479                                 }
1480                                 if (target_type == TypeManager.decimal_type)
1481                                         return new DecimalConstant ((decimal) v);
1482                         }
1483                         if (real_expr is UShortConstant){
1484                                 ushort v = ((UShortConstant) real_expr).Value;
1485
1486                                 if (target_type == TypeManager.byte_type) {
1487                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1488                                                 return null;
1489                                         return new ByteConstant ((byte) v);
1490                                 }
1491                                 if (target_type == TypeManager.sbyte_type) {
1492                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1493                                                 return null;
1494                                         return new SByteConstant ((sbyte) v);
1495                                 }
1496                                 if (target_type == TypeManager.short_type) {
1497                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1498                                                 return null;
1499                                         return new ShortConstant ((short) v);
1500                                 }
1501                                 if (target_type == TypeManager.int32_type)
1502                                         return new IntConstant ((int) v);
1503                                 if (target_type == TypeManager.uint32_type)
1504                                         return new UIntConstant ((uint) v);
1505                                 if (target_type == TypeManager.int64_type)
1506                                         return new LongConstant ((long) v);
1507                                 if (target_type == TypeManager.uint64_type)
1508                                         return new ULongConstant ((ulong) v);
1509                                 if (target_type == TypeManager.float_type)
1510                                         return new FloatConstant ((float) v);
1511                                 if (target_type == TypeManager.double_type)
1512                                         return new DoubleConstant ((double) v);
1513                                 if (target_type == TypeManager.char_type) {
1514                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1515                                                 return null;
1516                                         return new CharConstant ((char) v);
1517                                 }
1518                                 if (target_type == TypeManager.decimal_type)
1519                                         return new DecimalConstant ((decimal) v);
1520                         }
1521                         if (real_expr is IntConstant){
1522                                 int v = ((IntConstant) real_expr).Value;
1523
1524                                 if (target_type == TypeManager.byte_type) {
1525                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1526                                                 return null;
1527                                         return new ByteConstant ((byte) v);
1528                                 }
1529                                 if (target_type == TypeManager.sbyte_type) {
1530                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1531                                                 return null;
1532                                         return new SByteConstant ((sbyte) v);
1533                                 }
1534                                 if (target_type == TypeManager.short_type) {
1535                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1536                                                 return null;
1537                                         return new ShortConstant ((short) v);
1538                                 }
1539                                 if (target_type == TypeManager.ushort_type) {
1540                                         if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
1541                                                 return null;
1542                                         return new UShortConstant ((ushort) v);
1543                                 }
1544                                 if (target_type == TypeManager.uint32_type) {
1545                                         if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
1546                                                 return null;
1547                                         return new UIntConstant ((uint) v);
1548                                 }
1549                                 if (target_type == TypeManager.int64_type)
1550                                         return new LongConstant ((long) v);
1551                                 if (target_type == TypeManager.uint64_type) {
1552                                         if (!CheckUnsigned (ec, v, target_type))
1553                                                 return null;
1554                                         return new ULongConstant ((ulong) v);
1555                                 }
1556                                 if (target_type == TypeManager.float_type)
1557                                         return new FloatConstant ((float) v);
1558                                 if (target_type == TypeManager.double_type)
1559                                         return new DoubleConstant ((double) v);
1560                                 if (target_type == TypeManager.char_type) {
1561                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1562                                                 return null;
1563                                         return new CharConstant ((char) v);
1564                                 }
1565                                 if (target_type == TypeManager.decimal_type)
1566                                         return new DecimalConstant ((decimal) v);
1567                         }
1568                         if (real_expr is UIntConstant){
1569                                 uint v = ((UIntConstant) real_expr).Value;
1570
1571                                 if (target_type == TypeManager.byte_type) {
1572                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1573                                                 return null;
1574                                         return new ByteConstant ((byte) v);
1575                                 }
1576                                 if (target_type == TypeManager.sbyte_type) {
1577                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1578                                                 return null;
1579                                         return new SByteConstant ((sbyte) v);
1580                                 }
1581                                 if (target_type == TypeManager.short_type) {
1582                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1583                                                 return null;
1584                                         return new ShortConstant ((short) v);
1585                                 }
1586                                 if (target_type == TypeManager.ushort_type) {
1587                                         if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
1588                                                 return null;
1589                                         return new UShortConstant ((ushort) v);
1590                                 }
1591                                 if (target_type == TypeManager.int32_type) {
1592                                         if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
1593                                                 return null;
1594                                         return new IntConstant ((int) v);
1595                                 }
1596                                 if (target_type == TypeManager.int64_type)
1597                                         return new LongConstant ((long) v);
1598                                 if (target_type == TypeManager.uint64_type)
1599                                         return new ULongConstant ((ulong) v);
1600                                 if (target_type == TypeManager.float_type)
1601                                         return new FloatConstant ((float) v);
1602                                 if (target_type == TypeManager.double_type)
1603                                         return new DoubleConstant ((double) v);
1604                                 if (target_type == TypeManager.char_type) {
1605                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1606                                                 return null;
1607                                         return new CharConstant ((char) v);
1608                                 }
1609                                 if (target_type == TypeManager.decimal_type)
1610                                         return new DecimalConstant ((decimal) v);
1611                         }
1612                         if (real_expr is LongConstant){
1613                                 long v = ((LongConstant) real_expr).Value;
1614
1615                                 if (target_type == TypeManager.byte_type) {
1616                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1617                                                 return null;
1618                                         return new ByteConstant ((byte) v);
1619                                 }
1620                                 if (target_type == TypeManager.sbyte_type) {
1621                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1622                                                 return null;
1623                                         return new SByteConstant ((sbyte) v);
1624                                 }
1625                                 if (target_type == TypeManager.short_type) {
1626                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1627                                                 return null;
1628                                         return new ShortConstant ((short) v);
1629                                 }
1630                                 if (target_type == TypeManager.ushort_type) {
1631                                         if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
1632                                                 return null;
1633                                         return new UShortConstant ((ushort) v);
1634                                 }
1635                                 if (target_type == TypeManager.int32_type) {
1636                                         if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
1637                                                 return null;
1638                                         return new IntConstant ((int) v);
1639                                 }
1640                                 if (target_type == TypeManager.uint32_type) {
1641                                         if (!CheckRange (ec, v, target_type, UInt32.MinValue, UInt32.MaxValue))
1642                                                 return null;
1643                                         return new UIntConstant ((uint) v);
1644                                 }
1645                                 if (target_type == TypeManager.uint64_type) {
1646                                         if (!CheckUnsigned (ec, v, target_type))
1647                                                 return null;
1648                                         return new ULongConstant ((ulong) v);
1649                                 }
1650                                 if (target_type == TypeManager.float_type)
1651                                         return new FloatConstant ((float) v);
1652                                 if (target_type == TypeManager.double_type)
1653                                         return new DoubleConstant ((double) v);
1654                                 if (target_type == TypeManager.char_type) {
1655                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1656                                                 return null;
1657                                         return new CharConstant ((char) v);
1658                                 }
1659                                 if (target_type == TypeManager.decimal_type)
1660                                         return new DecimalConstant ((decimal) v);
1661                         }
1662                         if (real_expr is ULongConstant){
1663                                 ulong v = ((ULongConstant) real_expr).Value;
1664
1665                                 if (target_type == TypeManager.byte_type) {
1666                                         if (!CheckRange (ec, v, target_type, Byte.MaxValue))
1667                                                 return null;
1668                                         return new ByteConstant ((byte) v);
1669                                 }
1670                                 if (target_type == TypeManager.sbyte_type) {
1671                                         if (!CheckRange (ec, v, target_type, (ulong) SByte.MaxValue))
1672                                                 return null;
1673                                         return new SByteConstant ((sbyte) v);
1674                                 }
1675                                 if (target_type == TypeManager.short_type) {
1676                                         if (!CheckRange (ec, v, target_type, (ulong) Int16.MaxValue))
1677                                                 return null;
1678                                         return new ShortConstant ((short) v);
1679                                 }
1680                                 if (target_type == TypeManager.ushort_type) {
1681                                         if (!CheckRange (ec, v, target_type, UInt16.MaxValue))
1682                                                 return null;
1683                                         return new UShortConstant ((ushort) v);
1684                                 }
1685                                 if (target_type == TypeManager.int32_type) {
1686                                         if (!CheckRange (ec, v, target_type, Int32.MaxValue))
1687                                                 return null;
1688                                         return new IntConstant ((int) v);
1689                                 }
1690                                 if (target_type == TypeManager.uint32_type) {
1691                                         if (!CheckRange (ec, v, target_type, UInt32.MaxValue))
1692                                                 return null;
1693                                         return new UIntConstant ((uint) v);
1694                                 }
1695                                 if (target_type == TypeManager.int64_type) {
1696                                         if (!CheckRange (ec, v, target_type, (ulong) Int64.MaxValue))
1697                                                 return null;
1698                                         return new LongConstant ((long) v);
1699                                 }
1700                                 if (target_type == TypeManager.float_type)
1701                                         return new FloatConstant ((float) v);
1702                                 if (target_type == TypeManager.double_type)
1703                                         return new DoubleConstant ((double) v);
1704                                 if (target_type == TypeManager.char_type) {
1705                                         if (!CheckRange (ec, v, target_type, Char.MaxValue))
1706                                                 return null;
1707                                         return new CharConstant ((char) v);
1708                                 }
1709                                 if (target_type == TypeManager.decimal_type)
1710                                         return new DecimalConstant ((decimal) v);
1711                         }
1712                         if (real_expr is FloatConstant){
1713                                 float v = ((FloatConstant) real_expr).Value;
1714
1715                                 if (target_type == TypeManager.byte_type)
1716                                         return new ByteConstant ((byte) v);
1717                                 if (target_type == TypeManager.sbyte_type)
1718                                         return new SByteConstant ((sbyte) v);
1719                                 if (target_type == TypeManager.short_type)
1720                                         return new ShortConstant ((short) v);
1721                                 if (target_type == TypeManager.ushort_type)
1722                                         return new UShortConstant ((ushort) v);
1723                                 if (target_type == TypeManager.int32_type)
1724                                         return new IntConstant ((int) v);
1725                                 if (target_type == TypeManager.uint32_type)
1726                                         return new UIntConstant ((uint) v);
1727                                 if (target_type == TypeManager.int64_type)
1728                                         return new LongConstant ((long) v);
1729                                 if (target_type == TypeManager.uint64_type)
1730                                         return new ULongConstant ((ulong) v);
1731                                 if (target_type == TypeManager.double_type)
1732                                         return new DoubleConstant ((double) v);
1733                                 if (target_type == TypeManager.char_type)
1734                                         return new CharConstant ((char) v);
1735                                 if (target_type == TypeManager.decimal_type)
1736                                         return new DecimalConstant ((decimal) v);
1737                         }
1738                         if (real_expr is DoubleConstant){
1739                                 double v = ((DoubleConstant) real_expr).Value;
1740
1741                                 if (target_type == TypeManager.byte_type){
1742                                         return new ByteConstant ((byte) v);
1743                                 } if (target_type == TypeManager.sbyte_type)
1744                                         return new SByteConstant ((sbyte) v);
1745                                 if (target_type == TypeManager.short_type)
1746                                         return new ShortConstant ((short) v);
1747                                 if (target_type == TypeManager.ushort_type)
1748                                         return new UShortConstant ((ushort) v);
1749                                 if (target_type == TypeManager.int32_type)
1750                                         return new IntConstant ((int) v);
1751                                 if (target_type == TypeManager.uint32_type)
1752                                         return new UIntConstant ((uint) v);
1753                                 if (target_type == TypeManager.int64_type)
1754                                         return new LongConstant ((long) v);
1755                                 if (target_type == TypeManager.uint64_type)
1756                                         return new ULongConstant ((ulong) v);
1757                                 if (target_type == TypeManager.float_type)
1758                                         return new FloatConstant ((float) v);
1759                                 if (target_type == TypeManager.char_type)
1760                                         return new CharConstant ((char) v);
1761                                 if (target_type == TypeManager.decimal_type)
1762                                         return new DecimalConstant ((decimal) v);
1763                         }
1764
1765                         if (real_expr is CharConstant){
1766                                 char v = ((CharConstant) real_expr).Value;
1767
1768                                 if (target_type == TypeManager.byte_type) {
1769                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1770                                                 return null;
1771                                         return new ByteConstant ((byte) v);
1772                                 }
1773                                 if (target_type == TypeManager.sbyte_type) {
1774                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1775                                                 return null;
1776                                         return new SByteConstant ((sbyte) v);
1777                                 }
1778                                 if (target_type == TypeManager.short_type) {
1779                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1780                                                 return null;
1781                                         return new ShortConstant ((short) v);
1782                                 }
1783                                 if (target_type == TypeManager.int32_type)
1784                                         return new IntConstant ((int) v);
1785                                 if (target_type == TypeManager.uint32_type)
1786                                         return new UIntConstant ((uint) v);
1787                                 if (target_type == TypeManager.int64_type)
1788                                         return new LongConstant ((long) v);
1789                                 if (target_type == TypeManager.uint64_type)
1790                                         return new ULongConstant ((ulong) v);
1791                                 if (target_type == TypeManager.float_type)
1792                                         return new FloatConstant ((float) v);
1793                                 if (target_type == TypeManager.double_type)
1794                                         return new DoubleConstant ((double) v);
1795                                 if (target_type == TypeManager.char_type) {
1796                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1797                                                 return null;
1798                                         return new CharConstant ((char) v);
1799                                 }
1800                                 if (target_type == TypeManager.decimal_type)
1801                                         return new DecimalConstant ((decimal) v);
1802                         }
1803
1804                         return null;
1805                 }
1806
1807                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1808                 {
1809                         expr = expr.DoResolveLValue (ec, right_side);
1810                         if (expr == null)
1811                                 return null;
1812
1813                         return ResolveRest (ec);
1814                 }
1815
1816                 public override Expression DoResolve (EmitContext ec)
1817                 {
1818                         expr = expr.Resolve (ec);
1819                         if (expr == null)
1820                                 return null;
1821
1822                         return ResolveRest (ec);
1823                 }
1824
1825                 Expression ResolveRest (EmitContext ec)
1826                 {
1827                         TypeExpr target = target_type.ResolveAsTypeTerminal (ec);
1828                         if (target == null)
1829                                 return null;
1830
1831                         type = target.Type;
1832
1833                         CheckObsoleteAttribute (type);
1834
1835                         if (type.IsAbstract && type.IsSealed) {
1836                                 Report.Error (716, loc, "Cannot convert to static type '{0}'", TypeManager.CSharpName (type));
1837                                 return null;
1838                         }
1839
1840                         eclass = ExprClass.Value;
1841
1842                         if (expr is Constant){
1843                                 Expression e = TryReduce (ec, type);
1844
1845                                 if (e != null)
1846                                         return e;
1847                         }
1848
1849                         if (type.IsPointer && !ec.InUnsafe) {
1850                                 UnsafeError (loc);
1851                                 return null;
1852                         }
1853                         expr = Convert.ExplicitConversion (ec, expr, type, loc);
1854                         return expr;
1855                 }
1856
1857                 public override void Emit (EmitContext ec)
1858                 {
1859                         //
1860                         // This one will never happen
1861                         //
1862                         throw new Exception ("Should not happen");
1863                 }
1864         }
1865
1866         /// <summary>
1867         ///   Binary operators
1868         /// </summary>
1869         public class Binary : Expression {
1870                 public enum Operator : byte {
1871                         Multiply, Division, Modulus,
1872                         Addition, Subtraction,
1873                         LeftShift, RightShift,
1874                         LessThan, GreaterThan, LessThanOrEqual, GreaterThanOrEqual,
1875                         Equality, Inequality,
1876                         BitwiseAnd,
1877                         ExclusiveOr,
1878                         BitwiseOr,
1879                         LogicalAnd,
1880                         LogicalOr,
1881                         TOP
1882                 }
1883
1884                 Operator oper;
1885                 Expression left, right;
1886
1887                 // This must be kept in sync with Operator!!!
1888                 public static readonly string [] oper_names;
1889
1890                 static Binary ()
1891                 {
1892                         oper_names = new string [(int) Operator.TOP];
1893
1894                         oper_names [(int) Operator.Multiply] = "op_Multiply";
1895                         oper_names [(int) Operator.Division] = "op_Division";
1896                         oper_names [(int) Operator.Modulus] = "op_Modulus";
1897                         oper_names [(int) Operator.Addition] = "op_Addition";
1898                         oper_names [(int) Operator.Subtraction] = "op_Subtraction";
1899                         oper_names [(int) Operator.LeftShift] = "op_LeftShift";
1900                         oper_names [(int) Operator.RightShift] = "op_RightShift";
1901                         oper_names [(int) Operator.LessThan] = "op_LessThan";
1902                         oper_names [(int) Operator.GreaterThan] = "op_GreaterThan";
1903                         oper_names [(int) Operator.LessThanOrEqual] = "op_LessThanOrEqual";
1904                         oper_names [(int) Operator.GreaterThanOrEqual] = "op_GreaterThanOrEqual";
1905                         oper_names [(int) Operator.Equality] = "op_Equality";
1906                         oper_names [(int) Operator.Inequality] = "op_Inequality";
1907                         oper_names [(int) Operator.BitwiseAnd] = "op_BitwiseAnd";
1908                         oper_names [(int) Operator.BitwiseOr] = "op_BitwiseOr";
1909                         oper_names [(int) Operator.ExclusiveOr] = "op_ExclusiveOr";
1910                         oper_names [(int) Operator.LogicalOr] = "op_LogicalOr";
1911                         oper_names [(int) Operator.LogicalAnd] = "op_LogicalAnd";
1912                 }
1913
1914                 public Binary (Operator oper, Expression left, Expression right, Location loc)
1915                 {
1916                         this.oper = oper;
1917                         this.left = left;
1918                         this.right = right;
1919                         this.loc = loc;
1920                 }
1921
1922                 public Operator Oper {
1923                         get {
1924                                 return oper;
1925                         }
1926                         set {
1927                                 oper = value;
1928                         }
1929                 }
1930
1931                 public Expression Left {
1932                         get {
1933                                 return left;
1934                         }
1935                         set {
1936                                 left = value;
1937                         }
1938                 }
1939
1940                 public Expression Right {
1941                         get {
1942                                 return right;
1943                         }
1944                         set {
1945                                 right = value;
1946                         }
1947                 }
1948
1949
1950                 /// <summary>
1951                 ///   Returns a stringified representation of the Operator
1952                 /// </summary>
1953                 static string OperName (Operator oper)
1954                 {
1955                         switch (oper){
1956                         case Operator.Multiply:
1957                                 return "*";
1958                         case Operator.Division:
1959                                 return "/";
1960                         case Operator.Modulus:
1961                                 return "%";
1962                         case Operator.Addition:
1963                                 return "+";
1964                         case Operator.Subtraction:
1965                                 return "-";
1966                         case Operator.LeftShift:
1967                                 return "<<";
1968                         case Operator.RightShift:
1969                                 return ">>";
1970                         case Operator.LessThan:
1971                                 return "<";
1972                         case Operator.GreaterThan:
1973                                 return ">";
1974                         case Operator.LessThanOrEqual:
1975                                 return "<=";
1976                         case Operator.GreaterThanOrEqual:
1977                                 return ">=";
1978                         case Operator.Equality:
1979                                 return "==";
1980                         case Operator.Inequality:
1981                                 return "!=";
1982                         case Operator.BitwiseAnd:
1983                                 return "&";
1984                         case Operator.BitwiseOr:
1985                                 return "|";
1986                         case Operator.ExclusiveOr:
1987                                 return "^";
1988                         case Operator.LogicalOr:
1989                                 return "||";
1990                         case Operator.LogicalAnd:
1991                                 return "&&";
1992                         }
1993
1994                         return oper.ToString ();
1995                 }
1996
1997                 public override string ToString ()
1998                 {
1999                         return "operator " + OperName (oper) + "(" + left.ToString () + ", " +
2000                                 right.ToString () + ")";
2001                 }
2002
2003                 Expression ForceConversion (EmitContext ec, Expression expr, Type target_type)
2004                 {
2005                         if (expr.Type == target_type)
2006                                 return expr;
2007
2008                         return Convert.ImplicitConversion (ec, expr, target_type, loc);
2009                 }
2010
2011                 public static void Error_OperatorAmbiguous (Location loc, Operator oper, Type l, Type r)
2012                 {
2013                         Report.Error (
2014                                 34, loc, "Operator `" + OperName (oper)
2015                                 + "' is ambiguous on operands of type `"
2016                                 + TypeManager.CSharpName (l) + "' "
2017                                 + "and `" + TypeManager.CSharpName (r)
2018                                 + "'");
2019                 }
2020
2021                 bool IsOfType (EmitContext ec, Type l, Type r, Type t, bool check_user_conversions)
2022                 {
2023                         if ((l == t) || (r == t))
2024                                 return true;
2025
2026                         if (!check_user_conversions)
2027                                 return false;
2028
2029                         if (Convert.ImplicitUserConversionExists (ec, l, t))
2030                                 return true;
2031                         else if (Convert.ImplicitUserConversionExists (ec, r, t))
2032                                 return true;
2033                         else
2034                                 return false;
2035                 }
2036
2037                 //
2038                 // Note that handling the case l == Decimal || r == Decimal
2039                 // is taken care of by the Step 1 Operator Overload resolution.
2040                 //
2041                 // If `check_user_conv' is true, we also check whether a user-defined conversion
2042                 // exists.  Note that we only need to do this if both arguments are of a user-defined
2043                 // type, otherwise ConvertImplict() already finds the user-defined conversion for us,
2044                 // so we don't explicitly check for performance reasons.
2045                 //
2046                 bool DoNumericPromotions (EmitContext ec, Type l, Type r, bool check_user_conv)
2047                 {
2048                         if (IsOfType (ec, l, r, TypeManager.double_type, check_user_conv)){
2049                                 //
2050                                 // If either operand is of type double, the other operand is
2051                                 // conveted to type double.
2052                                 //
2053                                 if (r != TypeManager.double_type)
2054                                         right = Convert.ImplicitConversion (ec, right, TypeManager.double_type, loc);
2055                                 if (l != TypeManager.double_type)
2056                                         left = Convert.ImplicitConversion (ec, left, TypeManager.double_type, loc);
2057
2058                                 type = TypeManager.double_type;
2059                         } else if (IsOfType (ec, l, r, TypeManager.float_type, check_user_conv)){
2060                                 //
2061                                 // if either operand is of type float, the other operand is
2062                                 // converted to type float.
2063                                 //
2064                                 if (r != TypeManager.double_type)
2065                                         right = Convert.ImplicitConversion (ec, right, TypeManager.float_type, loc);
2066                                 if (l != TypeManager.double_type)
2067                                         left = Convert.ImplicitConversion (ec, left, TypeManager.float_type, loc);
2068                                 type = TypeManager.float_type;
2069                         } else if (IsOfType (ec, l, r, TypeManager.uint64_type, check_user_conv)){
2070                                 Expression e;
2071                                 Type other;
2072                                 //
2073                                 // If either operand is of type ulong, the other operand is
2074                                 // converted to type ulong.  or an error ocurrs if the other
2075                                 // operand is of type sbyte, short, int or long
2076                                 //
2077                                 if (l == TypeManager.uint64_type){
2078                                         if (r != TypeManager.uint64_type){
2079                                                 if (right is IntConstant){
2080                                                         IntConstant ic = (IntConstant) right;
2081
2082                                                         e = Convert.TryImplicitIntConversion (l, ic);
2083                                                         if (e != null)
2084                                                                 right = e;
2085                                                 } else if (right is LongConstant){
2086                                                         long ll = ((LongConstant) right).Value;
2087
2088                                                         if (ll >= 0)
2089                                                                 right = new ULongConstant ((ulong) ll);
2090                                                 } else {
2091                                                         e = Convert.ImplicitNumericConversion (ec, right, l, loc);
2092                                                         if (e != null)
2093                                                                 right = e;
2094                                                 }
2095                                         }
2096                                         other = right.Type;
2097                                 } else {
2098                                         if (left is IntConstant){
2099                                                 e = Convert.TryImplicitIntConversion (r, (IntConstant) left);
2100                                                 if (e != null)
2101                                                         left = e;
2102                                         } else if (left is LongConstant){
2103                                                 long ll = ((LongConstant) left).Value;
2104
2105                                                 if (ll > 0)
2106                                                         left = new ULongConstant ((ulong) ll);
2107                                         } else {
2108                                                 e = Convert.ImplicitNumericConversion (ec, left, r, loc);
2109                                                 if (e != null)
2110                                                         left = e;
2111                                         }
2112                                         other = left.Type;
2113                                 }
2114
2115                                 if ((other == TypeManager.sbyte_type) ||
2116                                     (other == TypeManager.short_type) ||
2117                                     (other == TypeManager.int32_type) ||
2118                                     (other == TypeManager.int64_type))
2119                                         Error_OperatorAmbiguous (loc, oper, l, r);
2120                                 else {
2121                                         left = ForceConversion (ec, left, TypeManager.uint64_type);
2122                                         right = ForceConversion (ec, right, TypeManager.uint64_type);
2123                                 }
2124                                 type = TypeManager.uint64_type;
2125                         } else if (IsOfType (ec, l, r, TypeManager.int64_type, check_user_conv)){
2126                                 //
2127                                 // If either operand is of type long, the other operand is converted
2128                                 // to type long.
2129                                 //
2130                                 if (l != TypeManager.int64_type)
2131                                         left = Convert.ImplicitConversion (ec, left, TypeManager.int64_type, loc);
2132                                 if (r != TypeManager.int64_type)
2133                                         right = Convert.ImplicitConversion (ec, right, TypeManager.int64_type, loc);
2134
2135                                 type = TypeManager.int64_type;
2136                         } else if (IsOfType (ec, l, r, TypeManager.uint32_type, check_user_conv)){
2137                                 //
2138                                 // If either operand is of type uint, and the other
2139                                 // operand is of type sbyte, short or int, othe operands are
2140                                 // converted to type long (unless we have an int constant).
2141                                 //
2142                                 Type other = null;
2143
2144                                 if (l == TypeManager.uint32_type){
2145                                         if (right is IntConstant){
2146                                                 IntConstant ic = (IntConstant) right;
2147                                                 int val = ic.Value;
2148
2149                                                 if (val >= 0){
2150                                                         right = new UIntConstant ((uint) val);
2151                                                         type = l;
2152
2153                                                         return true;
2154                                                 }
2155                                         }
2156                                         other = r;
2157                                 } else if (r == TypeManager.uint32_type){
2158                                         if (left is IntConstant){
2159                                                 IntConstant ic = (IntConstant) left;
2160                                                 int val = ic.Value;
2161
2162                                                 if (val >= 0){
2163                                                         left = new UIntConstant ((uint) val);
2164                                                         type = r;
2165                                                         return true;
2166                                                 }
2167                                         }
2168
2169                                         other = l;
2170                                 }
2171
2172                                 if ((other == TypeManager.sbyte_type) ||
2173                                     (other == TypeManager.short_type) ||
2174                                     (other == TypeManager.int32_type)){
2175                                         left = ForceConversion (ec, left, TypeManager.int64_type);
2176                                         right = ForceConversion (ec, right, TypeManager.int64_type);
2177                                         type = TypeManager.int64_type;
2178                                 } else {
2179                                         //
2180                                         // if either operand is of type uint, the other
2181                                         // operand is converd to type uint
2182                                         //
2183                                         left = ForceConversion (ec, left, TypeManager.uint32_type);
2184                                         right = ForceConversion (ec, right, TypeManager.uint32_type);
2185                                         type = TypeManager.uint32_type;
2186                                 }
2187                         } else if (l == TypeManager.decimal_type || r == TypeManager.decimal_type){
2188                                 if (l != TypeManager.decimal_type)
2189                                         left = Convert.ImplicitConversion (ec, left, TypeManager.decimal_type, loc);
2190
2191                                 if (r != TypeManager.decimal_type)
2192                                         right = Convert.ImplicitConversion (ec, right, TypeManager.decimal_type, loc);
2193                                 type = TypeManager.decimal_type;
2194                         } else {
2195                                 left = ForceConversion (ec, left, TypeManager.int32_type);
2196                                 right = ForceConversion (ec, right, TypeManager.int32_type);
2197
2198                                 type = TypeManager.int32_type;
2199                         }
2200
2201                         return (left != null) && (right != null);
2202                 }
2203
2204                 static public void Error_OperatorCannotBeApplied (Location loc, string name, Type l, Type r)
2205                 {
2206                         Report.Error (19, loc,
2207                                "Operator " + name + " cannot be applied to operands of type `" +
2208                                TypeManager.CSharpName (l) + "' and `" +
2209                                TypeManager.CSharpName (r) + "'");
2210                 }
2211
2212                 void Error_OperatorCannotBeApplied ()
2213                 {
2214                         Error_OperatorCannotBeApplied (loc, OperName (oper), left.Type, right.Type);
2215                 }
2216
2217                 static bool is_unsigned (Type t)
2218                 {
2219                         return (t == TypeManager.uint32_type || t == TypeManager.uint64_type ||
2220                                 t == TypeManager.short_type || t == TypeManager.byte_type);
2221                 }
2222
2223                 static bool is_user_defined (Type t)
2224                 {
2225                         if (t.IsSubclassOf (TypeManager.value_type) &&
2226                             (!TypeManager.IsBuiltinType (t) || t == TypeManager.decimal_type))
2227                                 return true;
2228                         else
2229                                 return false;
2230                 }
2231
2232                 Expression Make32or64 (EmitContext ec, Expression e)
2233                 {
2234                         Type t= e.Type;
2235
2236                         if (t == TypeManager.int32_type || t == TypeManager.uint32_type ||
2237                             t == TypeManager.int64_type || t == TypeManager.uint64_type)
2238                                 return e;
2239                         Expression ee = Convert.ImplicitConversion (ec, e, TypeManager.int32_type, loc);
2240                         if (ee != null)
2241                                 return ee;
2242                         ee = Convert.ImplicitConversion (ec, e, TypeManager.uint32_type, loc);
2243                         if (ee != null)
2244                                 return ee;
2245                         ee = Convert.ImplicitConversion (ec, e, TypeManager.int64_type, loc);
2246                         if (ee != null)
2247                                 return ee;
2248                         ee = Convert.ImplicitConversion (ec, e, TypeManager.uint64_type, loc);
2249                         if (ee != null)
2250                                 return ee;
2251                         return null;
2252                 }
2253
2254                 Expression CheckShiftArguments (EmitContext ec)
2255                 {
2256                         Expression e;
2257
2258                         e = ForceConversion (ec, right, TypeManager.int32_type);
2259                         if (e == null){
2260                                 Error_OperatorCannotBeApplied ();
2261                                 return null;
2262                         }
2263                         right = e;
2264
2265                         if (((e = Convert.ImplicitConversion (ec, left, TypeManager.int32_type, loc)) != null) ||
2266                             ((e = Convert.ImplicitConversion (ec, left, TypeManager.uint32_type, loc)) != null) ||
2267                             ((e = Convert.ImplicitConversion (ec, left, TypeManager.int64_type, loc)) != null) ||
2268                             ((e = Convert.ImplicitConversion (ec, left, TypeManager.uint64_type, loc)) != null)){
2269                                 left = e;
2270                                 type = e.Type;
2271
2272                                 if (type == TypeManager.int32_type || type == TypeManager.uint32_type){
2273                                         right = new Binary (Binary.Operator.BitwiseAnd, right, new IntLiteral (31), loc);
2274                                         right = right.DoResolve (ec);
2275                                 } else {
2276                                         right = new Binary (Binary.Operator.BitwiseAnd, right, new IntLiteral (63), loc);
2277                                         right = right.DoResolve (ec);
2278                                 }
2279
2280                                 return this;
2281                         }
2282                         Error_OperatorCannotBeApplied ();
2283                         return null;
2284                 }
2285
2286                 Expression ResolveOperator (EmitContext ec)
2287                 {
2288                         Type l = left.Type;
2289                         Type r = right.Type;
2290
2291                         //
2292                         // Special cases: string or type parameter comapred to null
2293                         //
2294                         if (oper == Operator.Equality || oper == Operator.Inequality){
2295                                 if ((!TypeManager.IsValueType (l) && r == TypeManager.null_type) ||
2296                                     (!TypeManager.IsValueType (r) && l == TypeManager.null_type)) {
2297                                         Type = TypeManager.bool_type;
2298
2299                                         return this;
2300                                 }
2301
2302                                 if (l.IsGenericParameter && (right is NullLiteral)) {
2303                                         if (l.BaseType == TypeManager.value_type) {
2304                                                 Error_OperatorCannotBeApplied ();
2305                                                 return null;
2306                                         }
2307
2308                                         left = new BoxedCast (left);
2309                                         Type = TypeManager.bool_type;
2310                                         return this;
2311                                 }
2312
2313                                 if (r.IsGenericParameter && (left is NullLiteral)) {
2314                                         if (r.BaseType == TypeManager.value_type) {
2315                                                 Error_OperatorCannotBeApplied ();
2316                                                 return null;
2317                                         }
2318
2319                                         right = new BoxedCast (right);
2320                                         Type = TypeManager.bool_type;
2321                                         return this;
2322                                 }
2323
2324                                 // IntPtr equality
2325                                 if (l == TypeManager.intptr_type && r == TypeManager.intptr_type) {
2326                                         Type = TypeManager.bool_type;
2327
2328                                         return this;
2329                                 }
2330                         }
2331
2332                         //
2333                         // Do not perform operator overload resolution when both sides are
2334                         // built-in types
2335                         //
2336                         if (!(TypeManager.IsCLRType (l) && TypeManager.IsCLRType (r))){
2337                                 //
2338                                 // Step 1: Perform Operator Overload location
2339                                 //
2340                                 Expression left_expr, right_expr;
2341
2342                                 string op = oper_names [(int) oper];
2343
2344                                 MethodGroupExpr union;
2345                                 left_expr = MemberLookup (ec, l, op, MemberTypes.Method, AllBindingFlags, loc);
2346                                 if (r != l){
2347                                         right_expr = MemberLookup (
2348                                                 ec, r, op, MemberTypes.Method, AllBindingFlags, loc);
2349                                         union = Invocation.MakeUnionSet (left_expr, right_expr, loc);
2350                                 } else
2351                                         union = (MethodGroupExpr) left_expr;
2352
2353                                 if (union != null) {
2354                                         ArrayList args = new ArrayList (2);
2355                                         args.Add (new Argument (left, Argument.AType.Expression));
2356                                         args.Add (new Argument (right, Argument.AType.Expression));
2357
2358                                         MethodBase method = Invocation.OverloadResolve (
2359                                                 ec, union, args, true, Location.Null);
2360
2361                                         if (method != null) {
2362                                                 MethodInfo mi = (MethodInfo) method;
2363
2364                                                 return new BinaryMethod (mi.ReturnType, method, args);
2365                                         }
2366                                 }
2367                         }
2368
2369                         //
2370                         // Step 0: String concatenation (because overloading will get this wrong)
2371                         //
2372                         if (oper == Operator.Addition){
2373                                 //
2374                                 // If any of the arguments is a string, cast to string
2375                                 //
2376
2377                                 // Simple constant folding
2378                                 if (left is StringConstant && right is StringConstant)
2379                                         return new StringConstant (((StringConstant) left).Value + ((StringConstant) right).Value);
2380
2381                                 if (l == TypeManager.string_type || r == TypeManager.string_type) {
2382
2383                                         if (r == TypeManager.void_type || l == TypeManager.void_type) {
2384                                                 Error_OperatorCannotBeApplied ();
2385                                                 return null;
2386                                         }
2387
2388                                         // try to fold it in on the left
2389                                         if (left is StringConcat) {
2390
2391                                                 //
2392                                                 // We have to test here for not-null, since we can be doubly-resolved
2393                                                 // take care of not appending twice
2394                                                 //
2395                                                 if (type == null){
2396                                                         type = TypeManager.string_type;
2397                                                         ((StringConcat) left).Append (ec, right);
2398                                                         return left.Resolve (ec);
2399                                                 } else {
2400                                                         return left;
2401                                                 }
2402                                         }
2403
2404                                         // Otherwise, start a new concat expression
2405                                         return new StringConcat (ec, loc, left, right).Resolve (ec);
2406                                 }
2407
2408                                 //
2409                                 // Transform a + ( - b) into a - b
2410                                 //
2411                                 if (right is Unary){
2412                                         Unary right_unary = (Unary) right;
2413
2414                                         if (right_unary.Oper == Unary.Operator.UnaryNegation){
2415                                                 oper = Operator.Subtraction;
2416                                                 right = right_unary.Expr;
2417                                                 r = right.Type;
2418                                         }
2419                                 }
2420                         }
2421
2422                         if (oper == Operator.Equality || oper == Operator.Inequality){
2423                                 if (l == TypeManager.bool_type || r == TypeManager.bool_type){
2424                                         if (r != TypeManager.bool_type || l != TypeManager.bool_type){
2425                                                 Error_OperatorCannotBeApplied ();
2426                                                 return null;
2427                                         }
2428
2429                                         type = TypeManager.bool_type;
2430                                         return this;
2431                                 }
2432
2433                                 bool left_is_null = left is NullLiteral;
2434                                 bool right_is_null = right is NullLiteral;
2435                                 if (left_is_null || right_is_null) {
2436                                         if (oper == Operator.Equality)
2437                                                 return new BoolLiteral (left_is_null == right_is_null);
2438                                         else
2439                                                 return new BoolLiteral (left_is_null != right_is_null);
2440                                 }
2441
2442                                 //
2443                                 // operator != (object a, object b)
2444                                 // operator == (object a, object b)
2445                                 //
2446                                 // For this to be used, both arguments have to be reference-types.
2447                                 // Read the rationale on the spec (14.9.6)
2448                                 //
2449                                 // Also, if at compile time we know that the classes do not inherit
2450                                 // one from the other, then we catch the error there.
2451                                 //
2452                                 if (!(l.IsValueType || r.IsValueType)){
2453                                         type = TypeManager.bool_type;
2454
2455                                         if (l == r)
2456                                                 return this;
2457
2458                                         if (l.IsSubclassOf (r) || r.IsSubclassOf (l))
2459                                                 return this;
2460
2461                                         //
2462                                         // Also, a standard conversion must exist from either one
2463                                         //
2464                                         if (!(Convert.ImplicitStandardConversionExists (ec, left, r) ||
2465                                               Convert.ImplicitStandardConversionExists (ec, right, l))){
2466                                                 Error_OperatorCannotBeApplied ();
2467                                                 return null;
2468                                         }
2469                                         //
2470                                         // We are going to have to convert to an object to compare
2471                                         //
2472                                         if (l != TypeManager.object_type)
2473                                                 left = new EmptyCast (left, TypeManager.object_type);
2474                                         if (r != TypeManager.object_type)
2475                                                 right = new EmptyCast (right, TypeManager.object_type);
2476
2477                                         //
2478                                         // FIXME: CSC here catches errors cs254 and cs252
2479                                         //
2480                                         return this;
2481                                 }
2482
2483                                 //
2484                                 // One of them is a valuetype, but the other one is not.
2485                                 //
2486                                 if (!l.IsValueType || !r.IsValueType) {
2487                                         Error_OperatorCannotBeApplied ();
2488                                         return null;
2489                                 }
2490                         }
2491
2492                         // Only perform numeric promotions on:
2493                         // +, -, *, /, %, &, |, ^, ==, !=, <, >, <=, >=
2494                         //
2495                         if (oper == Operator.Addition || oper == Operator.Subtraction) {
2496                                 if (TypeManager.IsDelegateType (l)){
2497                                         if (((right.eclass == ExprClass.MethodGroup) ||
2498                                              (r == TypeManager.anonymous_method_type))){
2499                                                 if ((RootContext.Version != LanguageVersion.ISO_1)){
2500                                                         Expression tmp = Convert.ImplicitConversionRequired (ec, right, l, loc);
2501                                                         if (tmp == null)
2502                                                                 return null;
2503                                                         right = tmp;
2504                                                         r = right.Type;
2505                                                 }
2506                                         }
2507
2508                                         if (TypeManager.IsDelegateType (r)){
2509                                                 MethodInfo method;
2510                                                 ArrayList args = new ArrayList (2);
2511
2512                                                 args = new ArrayList (2);
2513                                                 args.Add (new Argument (left, Argument.AType.Expression));
2514                                                 args.Add (new Argument (right, Argument.AType.Expression));
2515
2516                                                 if (oper == Operator.Addition)
2517                                                         method = TypeManager.delegate_combine_delegate_delegate;
2518                                                 else
2519                                                         method = TypeManager.delegate_remove_delegate_delegate;
2520
2521                                                 if (!TypeManager.IsEqual (l, r)) {
2522                                                         Error_OperatorCannotBeApplied ();
2523                                                         return null;
2524                                                 }
2525
2526                                                 return new BinaryDelegate (l, method, args);
2527                                         }
2528                                 }
2529
2530                                 //
2531                                 // Pointer arithmetic:
2532                                 //
2533                                 // T* operator + (T* x, int y);
2534                                 // T* operator + (T* x, uint y);
2535                                 // T* operator + (T* x, long y);
2536                                 // T* operator + (T* x, ulong y);
2537                                 //
2538                                 // T* operator + (int y,   T* x);
2539                                 // T* operator + (uint y,  T *x);
2540                                 // T* operator + (long y,  T *x);
2541                                 // T* operator + (ulong y, T *x);
2542                                 //
2543                                 // T* operator - (T* x, int y);
2544                                 // T* operator - (T* x, uint y);
2545                                 // T* operator - (T* x, long y);
2546                                 // T* operator - (T* x, ulong y);
2547                                 //
2548                                 // long operator - (T* x, T *y)
2549                                 //
2550                                 if (l.IsPointer){
2551                                         if (r.IsPointer && oper == Operator.Subtraction){
2552                                                 if (r == l)
2553                                                         return new PointerArithmetic (
2554                                                                 false, left, right, TypeManager.int64_type,
2555                                                                 loc).Resolve (ec);
2556                                         } else {
2557                                                 Expression t = Make32or64 (ec, right);
2558                                                 if (t != null)
2559                                                         return new PointerArithmetic (oper == Operator.Addition, left, t, l, loc).Resolve (ec);
2560                                         }
2561                                 } else if (r.IsPointer && oper == Operator.Addition){
2562                                         Expression t = Make32or64 (ec, left);
2563                                         if (t != null)
2564                                                 return new PointerArithmetic (true, right, t, r, loc).Resolve (ec);
2565                                 }
2566                         }
2567
2568                         //
2569                         // Enumeration operators
2570                         //
2571                         bool lie = TypeManager.IsEnumType (l);
2572                         bool rie = TypeManager.IsEnumType (r);
2573                         if (lie || rie){
2574                                 Expression temp;
2575
2576                                 // U operator - (E e, E f)
2577                                 if (lie && rie){
2578                                         if (oper == Operator.Subtraction){
2579                                         if (l == r){
2580                                                 type = TypeManager.EnumToUnderlying (l);
2581                                                 return this;
2582                                         }
2583                                         Error_OperatorCannotBeApplied ();
2584                                         return null;
2585                                 }
2586                                 }
2587
2588                                 //
2589                                 // operator + (E e, U x)
2590                                 // operator - (E e, U x)
2591                                 //
2592                                 if (oper == Operator.Addition || oper == Operator.Subtraction){
2593                                         Type enum_type = lie ? l : r;
2594                                         Type other_type = lie ? r : l;
2595                                         Type underlying_type = TypeManager.EnumToUnderlying (enum_type);
2596
2597                                         if (underlying_type != other_type){
2598                                                 temp = Convert.ImplicitConversion (ec, lie ? right : left, underlying_type, loc);
2599                                                 if (temp != null){
2600                                                         if (lie)
2601                                                                 right = temp;
2602                                                         else
2603                                                                 left = temp;
2604                                                         type = enum_type;
2605                                                         return this;
2606                                                 }
2607
2608                                                 Error_OperatorCannotBeApplied ();
2609                                                 return null;
2610                                         }
2611
2612                                         type = enum_type;
2613                                         return this;
2614                                 }
2615
2616                                 if (!rie){
2617                                         temp = Convert.ImplicitConversion (ec, right, l, loc);
2618                                         if (temp != null)
2619                                                 right = temp;
2620                                         else {
2621                                                 Error_OperatorCannotBeApplied ();
2622                                                 return null;
2623                                         }
2624                                 } if (!lie){
2625                                         temp = Convert.ImplicitConversion (ec, left, r, loc);
2626                                         if (temp != null){
2627                                                 left = temp;
2628                                                 l = r;
2629                                         } else {
2630                                                 Error_OperatorCannotBeApplied ();
2631                                                 return null;
2632                                         }
2633                                 }
2634
2635                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2636                                     oper == Operator.LessThanOrEqual || oper == Operator.LessThan ||
2637                                     oper == Operator.GreaterThanOrEqual || oper == Operator.GreaterThan){
2638                                         if (left.Type != right.Type){
2639                                                 Error_OperatorCannotBeApplied ();
2640                                                 return null;
2641                                         }
2642                                         type = TypeManager.bool_type;
2643                                         return this;
2644                                 }
2645
2646                                 if (oper == Operator.BitwiseAnd ||
2647                                     oper == Operator.BitwiseOr ||
2648                                     oper == Operator.ExclusiveOr){
2649                                         type = l;
2650                                         return this;
2651                                 }
2652                                 Error_OperatorCannotBeApplied ();
2653                                 return null;
2654                         }
2655
2656                         if (oper == Operator.LeftShift || oper == Operator.RightShift)
2657                                 return CheckShiftArguments (ec);
2658
2659                         if (oper == Operator.LogicalOr || oper == Operator.LogicalAnd){
2660                                 if (l == TypeManager.bool_type && r == TypeManager.bool_type) {
2661                                         type = TypeManager.bool_type;
2662                                         return this;
2663                                 }
2664
2665                                 if (l != r) {
2666                                         Error_OperatorCannotBeApplied ();
2667                                         return null;
2668                                 }
2669
2670                                 Expression e = new ConditionalLogicalOperator (
2671                                         oper == Operator.LogicalAnd, left, right, l, loc);
2672                                 return e.Resolve (ec);
2673                         }
2674
2675                         //
2676                         // operator & (bool x, bool y)
2677                         // operator | (bool x, bool y)
2678                         // operator ^ (bool x, bool y)
2679                         //
2680                         if (l == TypeManager.bool_type && r == TypeManager.bool_type){
2681                                 if (oper == Operator.BitwiseAnd ||
2682                                     oper == Operator.BitwiseOr ||
2683                                     oper == Operator.ExclusiveOr){
2684                                         type = l;
2685                                         return this;
2686                                 }
2687                         }
2688
2689                         //
2690                         // Pointer comparison
2691                         //
2692                         if (l.IsPointer && r.IsPointer){
2693                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2694                                     oper == Operator.LessThan || oper == Operator.LessThanOrEqual ||
2695                                     oper == Operator.GreaterThan || oper == Operator.GreaterThanOrEqual){
2696                                         type = TypeManager.bool_type;
2697                                         return this;
2698                                 }
2699                         }
2700
2701                         //
2702                         // This will leave left or right set to null if there is an error
2703                         //
2704                         bool check_user_conv = is_user_defined (l) && is_user_defined (r);
2705                         DoNumericPromotions (ec, l, r, check_user_conv);
2706                         if (left == null || right == null){
2707                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
2708                                 return null;
2709                         }
2710
2711                         //
2712                         // reload our cached types if required
2713                         //
2714                         l = left.Type;
2715                         r = right.Type;
2716
2717                         if (oper == Operator.BitwiseAnd ||
2718                             oper == Operator.BitwiseOr ||
2719                             oper == Operator.ExclusiveOr){
2720                                 if (l == r){
2721                                         if (((l == TypeManager.int32_type) ||
2722                                              (l == TypeManager.uint32_type) ||
2723                                              (l == TypeManager.short_type) ||
2724                                              (l == TypeManager.ushort_type) ||
2725                                              (l == TypeManager.int64_type) ||
2726                                              (l == TypeManager.uint64_type))){
2727                                                 type = l;
2728                                         } else {
2729                                                 Error_OperatorCannotBeApplied ();
2730                                                 return null;
2731                                         }
2732                                 } else {
2733                                         Error_OperatorCannotBeApplied ();
2734                                         return null;
2735                                 }
2736                         }
2737
2738                         if (oper == Operator.Equality ||
2739                             oper == Operator.Inequality ||
2740                             oper == Operator.LessThanOrEqual ||
2741                             oper == Operator.LessThan ||
2742                             oper == Operator.GreaterThanOrEqual ||
2743                             oper == Operator.GreaterThan){
2744                                 type = TypeManager.bool_type;
2745                         }
2746
2747                         return this;
2748                 }
2749
2750                 public override Expression DoResolve (EmitContext ec)
2751                 {
2752                         if ((oper == Operator.Subtraction) && (left is ParenthesizedExpression)) {
2753                                 left = ((ParenthesizedExpression) left).Expr;
2754                                 left = left.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.Type);
2755                                 if (left == null)
2756                                         return null;
2757
2758                                 if (left.eclass == ExprClass.Type) {
2759                                         Error (75, "Casting a negative value needs to have the value in parentheses.");
2760                                         return null;
2761                                 }
2762                         } else
2763                                 left = left.Resolve (ec);
2764
2765                         if (left == null)
2766                                 return null;
2767
2768                         Constant lc = left as Constant;
2769                         if (lc != null && lc.Type == TypeManager.bool_type &&
2770                                 ((oper == Operator.LogicalAnd && (bool)lc.GetValue () == false) ||
2771                                  (oper == Operator.LogicalOr && (bool)lc.GetValue () == true))) {
2772
2773                                 // TODO: make a sense to resolve unreachable expression as we do for statement
2774                                 Report.Warning (429, 4, loc, "Unreachable expression code detected");
2775                                 return left;
2776                         }
2777
2778                         right = right.Resolve (ec);
2779                         if (right == null)
2780                                 return null;
2781
2782                         eclass = ExprClass.Value;
2783
2784                         Constant rc = right as Constant;
2785                         if (rc != null & lc != null){
2786                                 Expression e = ConstantFold.BinaryFold (
2787                                         ec, oper, lc, rc, loc);
2788                                         if (e != null)
2789                                                 return e;
2790                         }
2791
2792                         if (TypeManager.IsNullableType (left.Type) || TypeManager.IsNullableType (right.Type))
2793                                 return new Nullable.LiftedBinaryOperator (oper, left, right, loc).Resolve (ec);
2794
2795                         return ResolveOperator (ec);
2796                 }
2797
2798                 /// <remarks>
2799                 ///   EmitBranchable is called from Statement.EmitBoolExpression in the
2800                 ///   context of a conditional bool expression.  This function will return
2801                 ///   false if it is was possible to use EmitBranchable, or true if it was.
2802                 ///
2803                 ///   The expression's code is generated, and we will generate a branch to `target'
2804                 ///   if the resulting expression value is equal to isTrue
2805                 /// </remarks>
2806                 public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
2807                 {
2808                         ILGenerator ig = ec.ig;
2809
2810                         //
2811                         // This is more complicated than it looks, but its just to avoid
2812                         // duplicated tests: basically, we allow ==, !=, >, <, >= and <=
2813                         // but on top of that we want for == and != to use a special path
2814                         // if we are comparing against null
2815                         //
2816                         if ((oper == Operator.Equality || oper == Operator.Inequality) && (left is Constant || right is Constant)) {
2817                                 bool my_on_true = oper == Operator.Inequality ? onTrue : !onTrue;
2818
2819                                 //
2820                                 // put the constant on the rhs, for simplicity
2821                                 //
2822                                 if (left is Constant) {
2823                                         Expression swap = right;
2824                                         right = left;
2825                                         left = swap;
2826                                 }
2827
2828                                 if (((Constant) right).IsZeroInteger) {
2829                                         left.Emit (ec);
2830                                         if (my_on_true)
2831                                                 ig.Emit (OpCodes.Brtrue, target);
2832                                         else
2833                                                 ig.Emit (OpCodes.Brfalse, target);
2834
2835                                         return;
2836                                 } else if (right is BoolConstant){
2837                                         left.Emit (ec);
2838                                         if (my_on_true != ((BoolConstant) right).Value)
2839                                                 ig.Emit (OpCodes.Brtrue, target);
2840                                         else
2841                                                 ig.Emit (OpCodes.Brfalse, target);
2842
2843                                         return;
2844                                 }
2845
2846                         } else if (oper == Operator.LogicalAnd) {
2847
2848                                 if (onTrue) {
2849                                                 Label tests_end = ig.DefineLabel ();
2850
2851                                         left.EmitBranchable (ec, tests_end, false);
2852                                         right.EmitBranchable (ec, target, true);
2853                                                         ig.MarkLabel (tests_end);
2854                                         } else {
2855                                         left.EmitBranchable (ec, target, false);
2856                                         right.EmitBranchable (ec, target, false);
2857                                         }
2858
2859                                 return;
2860
2861                         } else if (oper == Operator.LogicalOr){
2862                                 if (onTrue) {
2863                                         left.EmitBranchable (ec, target, true);
2864                                         right.EmitBranchable (ec, target, true);
2865
2866                                         } else {
2867                                                 Label tests_end = ig.DefineLabel ();
2868                                         left.EmitBranchable (ec, tests_end, true);
2869                                         right.EmitBranchable (ec, target, false);
2870                                         ig.MarkLabel (tests_end);
2871                                 }
2872
2873                                 return;
2874
2875                         } else if (!(oper == Operator.LessThan        || oper == Operator.GreaterThan ||
2876                                      oper == Operator.LessThanOrEqual || oper == Operator.GreaterThanOrEqual ||
2877                                      oper == Operator.Equality        || oper == Operator.Inequality)) {
2878                                 base.EmitBranchable (ec, target, onTrue);
2879                                 return;
2880                                 }
2881
2882                         left.Emit (ec);
2883                         right.Emit (ec);
2884
2885                         Type t = left.Type;
2886                         bool isUnsigned = is_unsigned (t) || t == TypeManager.double_type || t == TypeManager.float_type;
2887
2888                         switch (oper){
2889                         case Operator.Equality:
2890                                 if (onTrue)
2891                                         ig.Emit (OpCodes.Beq, target);
2892                                 else
2893                                         ig.Emit (OpCodes.Bne_Un, target);
2894                                 break;
2895
2896                         case Operator.Inequality:
2897                                 if (onTrue)
2898                                         ig.Emit (OpCodes.Bne_Un, target);
2899                                 else
2900                                         ig.Emit (OpCodes.Beq, target);
2901                                 break;
2902
2903                         case Operator.LessThan:
2904                                 if (onTrue)
2905                                         if (isUnsigned)
2906                                                 ig.Emit (OpCodes.Blt_Un, target);
2907                                         else
2908                                                 ig.Emit (OpCodes.Blt, target);
2909                                 else
2910                                         if (isUnsigned)
2911                                                 ig.Emit (OpCodes.Bge_Un, target);
2912                                         else
2913                                                 ig.Emit (OpCodes.Bge, target);
2914                                 break;
2915
2916                         case Operator.GreaterThan:
2917                                 if (onTrue)
2918                                         if (isUnsigned)
2919                                                 ig.Emit (OpCodes.Bgt_Un, target);
2920                                         else
2921                                                 ig.Emit (OpCodes.Bgt, target);
2922                                 else
2923                                         if (isUnsigned)
2924                                                 ig.Emit (OpCodes.Ble_Un, target);
2925                                         else
2926                                                 ig.Emit (OpCodes.Ble, target);
2927                                 break;
2928
2929                         case Operator.LessThanOrEqual:
2930                                 if (onTrue)
2931                                         if (isUnsigned)
2932                                                 ig.Emit (OpCodes.Ble_Un, target);
2933                                         else
2934                                                 ig.Emit (OpCodes.Ble, target);
2935                                 else
2936                                         if (isUnsigned)
2937                                                 ig.Emit (OpCodes.Bgt_Un, target);
2938                                         else
2939                                                 ig.Emit (OpCodes.Bgt, target);
2940                                 break;
2941
2942
2943                         case Operator.GreaterThanOrEqual:
2944                                 if (onTrue)
2945                                         if (isUnsigned)
2946                                                 ig.Emit (OpCodes.Bge_Un, target);
2947                                         else
2948                                                 ig.Emit (OpCodes.Bge, target);
2949                                 else
2950                                         if (isUnsigned)
2951                                                 ig.Emit (OpCodes.Blt_Un, target);
2952                                         else
2953                                                 ig.Emit (OpCodes.Blt, target);
2954                                 break;
2955                         default:
2956                                 Console.WriteLine (oper);
2957                                 throw new Exception ("what is THAT");
2958                         }
2959                 }
2960
2961                 public override void Emit (EmitContext ec)
2962                 {
2963                         ILGenerator ig = ec.ig;
2964                         Type l = left.Type;
2965                         OpCode opcode;
2966
2967                         //
2968                         // Handle short-circuit operators differently
2969                         // than the rest
2970                         //
2971                         if (oper == Operator.LogicalAnd) {
2972                                 Label load_zero = ig.DefineLabel ();
2973                                 Label end = ig.DefineLabel ();
2974
2975                                 left.EmitBranchable (ec, load_zero, false);
2976                                                 right.Emit (ec);
2977                                                 ig.Emit (OpCodes.Br, end);
2978
2979                                 ig.MarkLabel (load_zero);
2980                                 ig.Emit (OpCodes.Ldc_I4_0);
2981                                 ig.MarkLabel (end);
2982                                 return;
2983                         } else if (oper == Operator.LogicalOr) {
2984                                 Label load_one = ig.DefineLabel ();
2985                                 Label end = ig.DefineLabel ();
2986
2987                                 left.EmitBranchable (ec, load_one, true);
2988                                                 right.Emit (ec);
2989                                                 ig.Emit (OpCodes.Br, end);
2990
2991                                 ig.MarkLabel (load_one);
2992                                 ig.Emit (OpCodes.Ldc_I4_1);
2993                                 ig.MarkLabel (end);
2994                                 return;
2995                         }
2996
2997                         left.Emit (ec);
2998                         right.Emit (ec);
2999
3000                         bool isUnsigned = is_unsigned (left.Type);
3001
3002                         switch (oper){
3003                         case Operator.Multiply:
3004                                 if (ec.CheckState){
3005                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
3006                                                 opcode = OpCodes.Mul_Ovf;
3007                                         else if (isUnsigned)
3008                                                 opcode = OpCodes.Mul_Ovf_Un;
3009                                         else
3010                                                 opcode = OpCodes.Mul;
3011                                 } else
3012                                         opcode = OpCodes.Mul;
3013
3014                                 break;
3015
3016                         case Operator.Division:
3017                                 if (isUnsigned)
3018                                         opcode = OpCodes.Div_Un;
3019                                 else
3020                                         opcode = OpCodes.Div;
3021                                 break;
3022
3023                         case Operator.Modulus:
3024                                 if (isUnsigned)
3025                                         opcode = OpCodes.Rem_Un;
3026                                 else
3027                                         opcode = OpCodes.Rem;
3028                                 break;
3029
3030                         case Operator.Addition:
3031                                 if (ec.CheckState){
3032                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
3033                                                 opcode = OpCodes.Add_Ovf;
3034                                         else if (isUnsigned)
3035                                                 opcode = OpCodes.Add_Ovf_Un;
3036                                         else
3037                                                 opcode = OpCodes.Add;
3038                                 } else
3039                                         opcode = OpCodes.Add;
3040                                 break;
3041
3042                         case Operator.Subtraction:
3043                                 if (ec.CheckState){
3044                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
3045                                                 opcode = OpCodes.Sub_Ovf;
3046                                         else if (isUnsigned)
3047                                                 opcode = OpCodes.Sub_Ovf_Un;
3048                                         else
3049                                                 opcode = OpCodes.Sub;
3050                                 } else
3051                                         opcode = OpCodes.Sub;
3052                                 break;
3053
3054                         case Operator.RightShift:
3055                                 if (isUnsigned)
3056                                         opcode = OpCodes.Shr_Un;
3057                                 else
3058                                         opcode = OpCodes.Shr;
3059                                 break;
3060
3061                         case Operator.LeftShift:
3062                                 opcode = OpCodes.Shl;
3063                                 break;
3064
3065                         case Operator.Equality:
3066                                 opcode = OpCodes.Ceq;
3067                                 break;
3068
3069                         case Operator.Inequality:
3070                                 ig.Emit (OpCodes.Ceq);
3071                                 ig.Emit (OpCodes.Ldc_I4_0);
3072
3073                                 opcode = OpCodes.Ceq;
3074                                 break;
3075
3076                         case Operator.LessThan:
3077                                 if (isUnsigned)
3078                                         opcode = OpCodes.Clt_Un;
3079                                 else
3080                                         opcode = OpCodes.Clt;
3081                                 break;
3082
3083                         case Operator.GreaterThan:
3084                                 if (isUnsigned)
3085                                         opcode = OpCodes.Cgt_Un;
3086                                 else
3087                                         opcode = OpCodes.Cgt;
3088                                 break;
3089
3090                         case Operator.LessThanOrEqual:
3091                                 Type lt = left.Type;
3092
3093                                 if (isUnsigned || (lt == TypeManager.double_type || lt == TypeManager.float_type))
3094                                         ig.Emit (OpCodes.Cgt_Un);
3095                                 else
3096                                         ig.Emit (OpCodes.Cgt);
3097                                 ig.Emit (OpCodes.Ldc_I4_0);
3098
3099                                 opcode = OpCodes.Ceq;
3100                                 break;
3101
3102                         case Operator.GreaterThanOrEqual:
3103                                 Type le = left.Type;
3104
3105                                 if (isUnsigned || (le == TypeManager.double_type || le == TypeManager.float_type))
3106                                         ig.Emit (OpCodes.Clt_Un);
3107                                 else
3108                                         ig.Emit (OpCodes.Clt);
3109
3110                                 ig.Emit (OpCodes.Ldc_I4_0);
3111
3112                                 opcode = OpCodes.Ceq;
3113                                 break;
3114
3115                         case Operator.BitwiseOr:
3116                                 opcode = OpCodes.Or;
3117                                 break;
3118
3119                         case Operator.BitwiseAnd:
3120                                 opcode = OpCodes.And;
3121                                 break;
3122
3123                         case Operator.ExclusiveOr:
3124                                 opcode = OpCodes.Xor;
3125                                 break;
3126
3127                         default:
3128                                 throw new Exception ("This should not happen: Operator = "
3129                                                      + oper.ToString ());
3130                         }
3131
3132                         ig.Emit (opcode);
3133                 }
3134         }
3135
3136         //
3137         // Object created by Binary when the binary operator uses an method instead of being
3138         // a binary operation that maps to a CIL binary operation.
3139         //
3140         public class BinaryMethod : Expression {
3141                 public MethodBase method;
3142                 public ArrayList  Arguments;
3143
3144                 public BinaryMethod (Type t, MethodBase m, ArrayList args)
3145                 {
3146                         method = m;
3147                         Arguments = args;
3148                         type = t;
3149                         eclass = ExprClass.Value;
3150                 }
3151
3152                 public override Expression DoResolve (EmitContext ec)
3153                 {
3154                         return this;
3155                 }
3156
3157                 public override void Emit (EmitContext ec)
3158                 {
3159                         ILGenerator ig = ec.ig;
3160
3161                         if (Arguments != null)
3162                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
3163
3164                         if (method is MethodInfo)
3165                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
3166                         else
3167                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
3168                 }
3169         }
3170
3171         //
3172         // Represents the operation a + b [+ c [+ d [+ ...]]], where a is a string
3173         // b, c, d... may be strings or objects.
3174         //
3175         public class StringConcat : Expression {
3176                 ArrayList operands;
3177                 bool invalid = false;
3178                 bool emit_conv_done = false;
3179                 //
3180                 // Are we also concating objects?
3181                 //
3182                 bool is_strings_only = true;
3183
3184                 public StringConcat (EmitContext ec, Location loc, Expression left, Expression right)
3185                 {
3186                         this.loc = loc;
3187                         type = TypeManager.string_type;
3188                         eclass = ExprClass.Value;
3189
3190                         operands = new ArrayList (2);
3191                         Append (ec, left);
3192                         Append (ec, right);
3193                 }
3194
3195                 public override Expression DoResolve (EmitContext ec)
3196                 {
3197                         if (invalid)
3198                                 return null;
3199
3200                         return this;
3201                 }
3202
3203                 public void Append (EmitContext ec, Expression operand)
3204                 {
3205                         //
3206                         // Constant folding
3207                         //
3208                         if (operand is StringConstant && operands.Count != 0) {
3209                                 StringConstant last_operand = operands [operands.Count - 1] as StringConstant;
3210                                 if (last_operand != null) {
3211                                         operands [operands.Count - 1] = new StringConstant (last_operand.Value + ((StringConstant) operand).Value);
3212                                         return;
3213                                 }
3214                         }
3215
3216                         //
3217                         // Conversion to object
3218                         //
3219                         if (operand.Type != TypeManager.string_type) {
3220                                 Expression no = Convert.ImplicitConversion (ec, operand, TypeManager.object_type, loc);
3221
3222                                 if (no == null) {
3223                                         Binary.Error_OperatorCannotBeApplied (loc, "+", TypeManager.string_type, operand.Type);
3224                                         invalid = true;
3225                                 }
3226                                 operand = no;
3227                         }
3228
3229                         operands.Add (operand);
3230                 }
3231
3232                 public override void Emit (EmitContext ec)
3233                 {
3234                         MethodInfo concat_method = null;
3235
3236                         //
3237                         // Do conversion to arguments; check for strings only
3238                         //
3239
3240                         // This can get called multiple times, so we have to deal with that.
3241                         if (!emit_conv_done) {
3242                                 emit_conv_done = true;
3243                         for (int i = 0; i < operands.Count; i ++) {
3244                                 Expression e = (Expression) operands [i];
3245                                 is_strings_only &= e.Type == TypeManager.string_type;
3246                         }
3247
3248                         for (int i = 0; i < operands.Count; i ++) {
3249                                 Expression e = (Expression) operands [i];
3250
3251                                 if (! is_strings_only && e.Type == TypeManager.string_type) {
3252                                         // need to make sure this is an object, because the EmitParams
3253                                         // method might look at the type of this expression, see it is a
3254                                         // string and emit a string [] when we want an object [];
3255
3256                                                 e = new EmptyCast (e, TypeManager.object_type);
3257                                 }
3258                                 operands [i] = new Argument (e, Argument.AType.Expression);
3259                         }
3260                         }
3261
3262                         //
3263                         // Find the right method
3264                         //
3265                         switch (operands.Count) {
3266                         case 1:
3267                                 //
3268                                 // This should not be possible, because simple constant folding
3269                                 // is taken care of in the Binary code.
3270                                 //
3271                                 throw new Exception ("how did you get here?");
3272
3273                         case 2:
3274                                 concat_method = is_strings_only ?
3275                                         TypeManager.string_concat_string_string :
3276                                         TypeManager.string_concat_object_object ;
3277                                 break;
3278                         case 3:
3279                                 concat_method = is_strings_only ?
3280                                         TypeManager.string_concat_string_string_string :
3281                                         TypeManager.string_concat_object_object_object ;
3282                                 break;
3283                         case 4:
3284                                 //
3285                                 // There is not a 4 param overlaod for object (the one that there is
3286                                 // is actually a varargs methods, and is only in corlib because it was
3287                                 // introduced there before.).
3288                                 //
3289                                 if (!is_strings_only)
3290                                         goto default;
3291
3292                                 concat_method = TypeManager.string_concat_string_string_string_string;
3293                                 break;
3294                         default:
3295                                 concat_method = is_strings_only ?
3296                                         TypeManager.string_concat_string_dot_dot_dot :
3297                                         TypeManager.string_concat_object_dot_dot_dot ;
3298                                 break;
3299                         }
3300
3301                         Invocation.EmitArguments (ec, concat_method, operands, false, null);
3302                         ec.ig.Emit (OpCodes.Call, concat_method);
3303                 }
3304         }
3305
3306         //
3307         // Object created with +/= on delegates
3308         //
3309         public class BinaryDelegate : Expression {
3310                 MethodInfo method;
3311                 ArrayList  args;
3312
3313                 public BinaryDelegate (Type t, MethodInfo mi, ArrayList args)
3314                 {
3315                         method = mi;
3316                         this.args = args;
3317                         type = t;
3318                         eclass = ExprClass.Value;
3319                 }
3320
3321                 public override Expression DoResolve (EmitContext ec)
3322                 {
3323                         return this;
3324                 }
3325
3326                 public override void Emit (EmitContext ec)
3327                 {
3328                         ILGenerator ig = ec.ig;
3329
3330                         Invocation.EmitArguments (ec, method, args, false, null);
3331
3332                         ig.Emit (OpCodes.Call, (MethodInfo) method);
3333                         ig.Emit (OpCodes.Castclass, type);
3334                 }
3335
3336                 public Expression Right {
3337                         get {
3338                                 Argument arg = (Argument) args [1];
3339                                 return arg.Expr;
3340                         }
3341                 }
3342
3343                 public bool IsAddition {
3344                         get {
3345                                 return method == TypeManager.delegate_combine_delegate_delegate;
3346                         }
3347                 }
3348         }
3349
3350         //
3351         // User-defined conditional logical operator
3352         public class ConditionalLogicalOperator : Expression {
3353                 Expression left, right;
3354                 bool is_and;
3355
3356                 public ConditionalLogicalOperator (bool is_and, Expression left, Expression right, Type t, Location loc)
3357                 {
3358                         type = t;
3359                         eclass = ExprClass.Value;
3360                         this.loc = loc;
3361                         this.left = left;
3362                         this.right = right;
3363                         this.is_and = is_and;
3364                 }
3365
3366                 protected void Error19 ()
3367                 {
3368                         Binary.Error_OperatorCannotBeApplied (loc, is_and ? "&&" : "||", type, type);
3369                 }
3370
3371                 protected void Error218 ()
3372                 {
3373                         Error (218, "The type ('" + TypeManager.CSharpName (type) + "') must contain " +
3374                                "declarations of operator true and operator false");
3375                 }
3376
3377                 Expression op_true, op_false, op;
3378                 LocalTemporary left_temp;
3379
3380                 public override Expression DoResolve (EmitContext ec)
3381                 {
3382                         MethodInfo method;
3383                         Expression operator_group;
3384
3385                         operator_group = MethodLookup (ec, type, is_and ? "op_BitwiseAnd" : "op_BitwiseOr", loc);
3386                         if (operator_group == null) {
3387                                 Error19 ();
3388                                 return null;
3389                         }
3390
3391                         left_temp = new LocalTemporary (ec, type);
3392
3393                         ArrayList arguments = new ArrayList ();
3394                         arguments.Add (new Argument (left_temp, Argument.AType.Expression));
3395                         arguments.Add (new Argument (right, Argument.AType.Expression));
3396                         method = Invocation.OverloadResolve (
3397                                 ec, (MethodGroupExpr) operator_group, arguments, false, loc)
3398                                 as MethodInfo;
3399                         if ((method == null) || (method.ReturnType != type)) {
3400                                 Error19 ();
3401                                 return null;
3402                         }
3403
3404                         op = new StaticCallExpr (method, arguments, loc);
3405
3406                         op_true = GetOperatorTrue (ec, left_temp, loc);
3407                         op_false = GetOperatorFalse (ec, left_temp, loc);
3408                         if ((op_true == null) || (op_false == null)) {
3409                                 Error218 ();
3410                                 return null;
3411                         }
3412
3413                         return this;
3414                 }
3415
3416                 public override void Emit (EmitContext ec)
3417                 {
3418                         ILGenerator ig = ec.ig;
3419                         Label false_target = ig.DefineLabel ();
3420                         Label end_target = ig.DefineLabel ();
3421
3422                         left.Emit (ec);
3423                         left_temp.Store (ec);
3424
3425                         (is_and ? op_false : op_true).EmitBranchable (ec, false_target, false);
3426                         left_temp.Emit (ec);
3427                         ig.Emit (OpCodes.Br, end_target);
3428                         ig.MarkLabel (false_target);
3429                         op.Emit (ec);
3430                         ig.MarkLabel (end_target);
3431                 }
3432         }
3433
3434         public class PointerArithmetic : Expression {
3435                 Expression left, right;
3436                 bool is_add;
3437
3438                 //
3439                 // We assume that `l' is always a pointer
3440                 //
3441                 public PointerArithmetic (bool is_addition, Expression l, Expression r, Type t, Location loc)
3442                 {
3443                         type = t;
3444                         this.loc = loc;
3445                         left = l;
3446                         right = r;
3447                         is_add = is_addition;
3448                 }
3449
3450                 public override Expression DoResolve (EmitContext ec)
3451                 {
3452                         eclass = ExprClass.Variable;
3453
3454                         if (left.Type == TypeManager.void_ptr_type) {
3455                                 Error (242, "The operation in question is undefined on void pointers");
3456                                 return null;
3457                         }
3458
3459                         return this;
3460                 }
3461
3462                 public override void Emit (EmitContext ec)
3463                 {
3464                         Type op_type = left.Type;
3465                         ILGenerator ig = ec.ig;
3466
3467                         // It must be either array or fixed buffer
3468                         Type element = TypeManager.HasElementType (op_type) ?
3469                                 element = TypeManager.GetElementType (op_type) :
3470                                 element = AttributeTester.GetFixedBuffer (((FieldExpr)left).FieldInfo).ElementType;
3471
3472                         int size = GetTypeSize (element);
3473                         Type rtype = right.Type;
3474
3475                         if (rtype.IsPointer){
3476                                 //
3477                                 // handle (pointer - pointer)
3478                                 //
3479                                 left.Emit (ec);
3480                                 right.Emit (ec);
3481                                 ig.Emit (OpCodes.Sub);
3482
3483                                 if (size != 1){
3484                                         if (size == 0)
3485                                                 ig.Emit (OpCodes.Sizeof, element);
3486                                         else
3487                                                 IntLiteral.EmitInt (ig, size);
3488                                         ig.Emit (OpCodes.Div);
3489                                 }
3490                                 ig.Emit (OpCodes.Conv_I8);
3491                         } else {
3492                                 //
3493                                 // handle + and - on (pointer op int)
3494                                 //
3495                                 left.Emit (ec);
3496                                 ig.Emit (OpCodes.Conv_I);
3497
3498                                 Constant right_const = right as Constant;
3499                                 if (right_const != null && size != 0) {
3500                                         Expression ex = ConstantFold.BinaryFold (ec, Binary.Operator.Multiply, new IntConstant (size), right_const, loc);
3501                                         if (ex == null)
3502                                                 return;
3503                                         ex.Emit (ec);
3504                                 } else {
3505                                         right.Emit (ec);
3506                                         if (size != 1){
3507                                                 if (size == 0)
3508                                                         ig.Emit (OpCodes.Sizeof, element);
3509                                                 else
3510                                                         IntLiteral.EmitInt (ig, size);
3511                                                 if (rtype == TypeManager.int64_type)
3512                                                         ig.Emit (OpCodes.Conv_I8);
3513                                                 else if (rtype == TypeManager.uint64_type)
3514                                                         ig.Emit (OpCodes.Conv_U8);
3515                                                 ig.Emit (OpCodes.Mul);
3516                                         }
3517                                 }
3518
3519                                 if (rtype == TypeManager.int64_type || rtype == TypeManager.uint64_type)
3520                                         ig.Emit (OpCodes.Conv_I);
3521
3522                                 if (is_add)
3523                                         ig.Emit (OpCodes.Add);
3524                                 else
3525                                         ig.Emit (OpCodes.Sub);
3526                         }
3527                 }
3528         }
3529
3530         /// <summary>
3531         ///   Implements the ternary conditional operator (?:)
3532         /// </summary>
3533         public class Conditional : Expression {
3534                 Expression expr, trueExpr, falseExpr;
3535
3536                 public Conditional (Expression expr, Expression trueExpr, Expression falseExpr, Location l)
3537                 {
3538                         this.expr = expr;
3539                         this.trueExpr = trueExpr;
3540                         this.falseExpr = falseExpr;
3541                         this.loc = l;
3542                 }
3543
3544                 public Expression Expr {
3545                         get {
3546                                 return expr;
3547                         }
3548                 }
3549
3550                 public Expression TrueExpr {
3551                         get {
3552                                 return trueExpr;
3553                         }
3554                 }
3555
3556                 public Expression FalseExpr {
3557                         get {
3558                                 return falseExpr;
3559                         }
3560                 }
3561
3562                 public override Expression DoResolve (EmitContext ec)
3563                 {
3564                         expr = expr.Resolve (ec);
3565
3566                         if (expr == null)
3567                                 return null;
3568
3569                         if (TypeManager.IsNullableType (expr.Type))
3570                                 return new Nullable.LiftedConditional (expr, trueExpr, falseExpr, loc).Resolve (ec);
3571
3572                         if (expr.Type != TypeManager.bool_type){
3573                                 expr = Expression.ResolveBoolean (
3574                                         ec, expr, loc);
3575
3576                                 if (expr == null)
3577                                         return null;
3578                         }
3579
3580                         trueExpr = trueExpr.Resolve (ec);
3581                         falseExpr = falseExpr.Resolve (ec);
3582
3583                         if (trueExpr == null || falseExpr == null)
3584                                 return null;
3585
3586                         eclass = ExprClass.Value;
3587                         if (trueExpr.Type == falseExpr.Type)
3588                                 type = trueExpr.Type;
3589                         else {
3590                                 Expression conv;
3591                                 Type true_type = trueExpr.Type;
3592                                 Type false_type = falseExpr.Type;
3593
3594                                 //
3595                                 // First, if an implicit conversion exists from trueExpr
3596                                 // to falseExpr, then the result type is of type falseExpr.Type
3597                                 //
3598                                 conv = Convert.ImplicitConversion (ec, trueExpr, false_type, loc);
3599                                 if (conv != null){
3600                                         //
3601                                         // Check if both can convert implicitl to each other's type
3602                                         //
3603                                         if (Convert.ImplicitConversion (ec, falseExpr, true_type, loc) != null){
3604                                                 Error (172,
3605                                                        "Can not compute type of conditional expression " +
3606                                                        "as `" + TypeManager.CSharpName (trueExpr.Type) +
3607                                                        "' and `" + TypeManager.CSharpName (falseExpr.Type) +
3608                                                        "' convert implicitly to each other");
3609                                                 return null;
3610                                         }
3611                                         type = false_type;
3612                                         trueExpr = conv;
3613                                 } else if ((conv = Convert.ImplicitConversion(ec, falseExpr, true_type,loc))!= null){
3614                                         type = true_type;
3615                                         falseExpr = conv;
3616                                 } else {
3617                                         Error (173, "The type of the conditional expression can " +
3618                                                "not be computed because there is no implicit conversion" +
3619                                                " from `" + TypeManager.CSharpName (trueExpr.Type) + "'" +
3620                                                " and `" + TypeManager.CSharpName (falseExpr.Type) + "'");
3621                                         return null;
3622                                 }
3623                         }
3624
3625                         // Dead code optimalization
3626                         if (expr is BoolConstant){
3627                                 BoolConstant bc = (BoolConstant) expr;
3628
3629                                 Report.Warning (429, 4, bc.Value ? falseExpr.Location : trueExpr.Location, "Unreachable expression code detected");
3630                                 return bc.Value ? trueExpr : falseExpr;
3631                         }
3632
3633                         return this;
3634                 }
3635
3636                 public override void Emit (EmitContext ec)
3637                 {
3638                         ILGenerator ig = ec.ig;
3639                         Label false_target = ig.DefineLabel ();
3640                         Label end_target = ig.DefineLabel ();
3641
3642                         expr.EmitBranchable (ec, false_target, false);
3643                         trueExpr.Emit (ec);
3644                         ig.Emit (OpCodes.Br, end_target);
3645                         ig.MarkLabel (false_target);
3646                         falseExpr.Emit (ec);
3647                         ig.MarkLabel (end_target);
3648                 }
3649
3650         }
3651
3652         /// <summary>
3653         ///   Local variables
3654         /// </summary>
3655         public class LocalVariableReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
3656                 public readonly string Name;
3657                 public readonly Block Block;
3658                 public LocalInfo local_info;
3659                 bool is_readonly;
3660                 bool prepared;
3661                 LocalTemporary temp;
3662
3663                 public LocalVariableReference (Block block, string name, Location l)
3664                 {
3665                         Block = block;
3666                         Name = name;
3667                         loc = l;
3668                         eclass = ExprClass.Variable;
3669                 }
3670
3671                 //
3672                 // Setting `is_readonly' to false will allow you to create a writable
3673                 // reference to a read-only variable.  This is used by foreach and using.
3674                 //
3675                 public LocalVariableReference (Block block, string name, Location l,
3676                                                LocalInfo local_info, bool is_readonly)
3677                         : this (block, name, l)
3678                 {
3679                         this.local_info = local_info;
3680                         this.is_readonly = is_readonly;
3681                 }
3682
3683                 public VariableInfo VariableInfo {
3684                         get {
3685                                 return local_info.VariableInfo;
3686                         }
3687                 }
3688
3689                 public bool IsReadOnly {
3690                         get {
3691                                 return is_readonly;
3692                         }
3693                 }
3694
3695                 protected Expression DoResolveBase (EmitContext ec, Expression lvalue_right_side)
3696                 {
3697                         if (local_info == null) {
3698                                 local_info = Block.GetLocalInfo (Name);
3699
3700                                 // is out param
3701                                 if (lvalue_right_side == EmptyExpression.Null)
3702                                         local_info.Used = true;
3703
3704                                 is_readonly = local_info.ReadOnly;
3705                         }
3706
3707                         type = local_info.VariableType;
3708
3709                         VariableInfo variable_info = local_info.VariableInfo;
3710                         if (lvalue_right_side != null){
3711                                 if (is_readonly){
3712                                         Error (1604, "cannot assign to `" + Name + "' because it is readonly");
3713                                         return null;
3714                                 }
3715
3716                                 if (variable_info != null)
3717                                         variable_info.SetAssigned (ec);
3718                 }
3719
3720                         Expression e = Block.GetConstantExpression (Name);
3721                         if (e != null) {
3722                                 local_info.Used = true;
3723                                 eclass = ExprClass.Value;
3724                                 return e.Resolve (ec);
3725                         }
3726
3727                         if ((variable_info != null) && !variable_info.IsAssigned (ec, loc))
3728                                 return null;
3729
3730                         if (lvalue_right_side == null)
3731                                 local_info.Used = true;
3732
3733                         if (ec.CurrentAnonymousMethod != null){
3734                                 //
3735                                 // If we are referencing a variable from the external block
3736                                 // flag it for capturing
3737                                 //
3738                                 if (local_info.Block.Toplevel != ec.CurrentBlock.Toplevel){
3739                                         if (local_info.AddressTaken){
3740                                                 AnonymousMethod.Error_AddressOfCapturedVar (local_info.Name, loc);
3741                                                 return null;
3742                                         }
3743                                         ec.CaptureVariable (local_info);
3744                                 }
3745                         }
3746
3747                         return this;
3748                 }
3749
3750                 public override Expression DoResolve (EmitContext ec)
3751                 {
3752                         return DoResolveBase (ec, null);
3753                 }
3754
3755                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3756                 {
3757                         Expression ret = DoResolveBase (ec, right_side);
3758                         if (ret != null)
3759                                 CheckObsoleteAttribute (ret.Type);
3760
3761                         return ret;
3762                 }
3763
3764                 public bool VerifyFixed (bool is_expression)
3765                 {
3766                         return !is_expression || local_info.IsFixed;
3767                 }
3768
3769                 public override void Emit (EmitContext ec)
3770                 {
3771                         ILGenerator ig = ec.ig;
3772
3773                         if (local_info.FieldBuilder == null){
3774                                 //
3775                                 // A local variable on the local CLR stack
3776                                 //
3777                         ig.Emit (OpCodes.Ldloc, local_info.LocalBuilder);
3778                         } else {
3779                                 //
3780                                 // A local variable captured by anonymous methods.
3781                                 //
3782                                 if (!prepared)
3783                                         ec.EmitCapturedVariableInstance (local_info);
3784
3785                                 ig.Emit (OpCodes.Ldfld, local_info.FieldBuilder);
3786                         }
3787                 }
3788
3789                 public void Emit (EmitContext ec, bool leave_copy)
3790                 {
3791                         Emit (ec);
3792                         if (leave_copy){
3793                                 ec.ig.Emit (OpCodes.Dup);
3794                                 if (local_info.FieldBuilder != null){
3795                                         temp = new LocalTemporary (ec, Type);
3796                                         temp.Store (ec);
3797                                 }
3798                         }
3799                 }
3800
3801                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3802                 {
3803                         ILGenerator ig = ec.ig;
3804                         prepared = prepare_for_load;
3805
3806                         if (local_info.FieldBuilder == null){
3807                                 //
3808                                 // A local variable on the local CLR stack
3809                                 //
3810                                 if (local_info.LocalBuilder == null)
3811                                         throw new Exception ("This should not happen: both Field and Local are null");
3812
3813                         source.Emit (ec);
3814                         if (leave_copy)
3815                                 ec.ig.Emit (OpCodes.Dup);
3816                                 ig.Emit (OpCodes.Stloc, local_info.LocalBuilder);
3817                         } else {
3818                                 //
3819                                 // A local variable captured by anonymous methods or itereators.
3820                                 //
3821                                 ec.EmitCapturedVariableInstance (local_info);
3822
3823                                 if (prepare_for_load)
3824                                         ig.Emit (OpCodes.Dup);
3825                                 source.Emit (ec);
3826                                 if (leave_copy){
3827                                         ig.Emit (OpCodes.Dup);
3828                                         temp = new LocalTemporary (ec, Type);
3829                                         temp.Store (ec);
3830                                 }
3831                                 ig.Emit (OpCodes.Stfld, local_info.FieldBuilder);
3832                                 if (temp != null)
3833                                         temp.Emit (ec);
3834                         }
3835                 }
3836
3837                 public void AddressOf (EmitContext ec, AddressOp mode)
3838                 {
3839                         ILGenerator ig = ec.ig;
3840
3841                         if (local_info.FieldBuilder == null){
3842                                 //
3843                                 // A local variable on the local CLR stack
3844                                 //
3845                         ig.Emit (OpCodes.Ldloca, local_info.LocalBuilder);
3846                         } else {
3847                                 //
3848                                 // A local variable captured by anonymous methods or iterators
3849                                 //
3850                                 ec.EmitCapturedVariableInstance (local_info);
3851                                 ig.Emit (OpCodes.Ldflda, local_info.FieldBuilder);
3852                         }
3853                 }
3854
3855                 public override string ToString ()
3856                 {
3857                         return String.Format ("{0} ({1}:{2})", GetType (), Name, loc);
3858                 }
3859         }
3860
3861         /// <summary>
3862         ///   This represents a reference to a parameter in the intermediate
3863         ///   representation.
3864         /// </summary>
3865         public class ParameterReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
3866                 Parameters pars;
3867                 String name;
3868                 int idx;
3869                 Block block;
3870                 VariableInfo vi;
3871                 public Parameter.Modifier mod;
3872                 public bool is_ref, is_out, prepared;
3873
3874                 public bool IsOut {
3875                         get {
3876                                 return is_out;
3877                         }
3878                 }
3879
3880                 public bool IsRef {
3881                         get {
3882                                 return is_ref;
3883                         }
3884                 }
3885
3886                 LocalTemporary temp;
3887
3888                 public ParameterReference (Parameters pars, Block block, int idx, string name, Location loc)
3889                 {
3890                         this.pars = pars;
3891                         this.block = block;
3892                         this.idx  = idx;
3893                         this.name = name;
3894                         this.loc = loc;
3895                         eclass = ExprClass.Variable;
3896                 }
3897
3898                 public VariableInfo VariableInfo {
3899                         get { return vi; }
3900                 }
3901
3902                 public bool VerifyFixed (bool is_expression)
3903                 {
3904                         return !is_expression || TypeManager.IsValueType (type);
3905                 }
3906
3907                 public bool IsAssigned (EmitContext ec, Location loc)
3908                 {
3909                         if (!ec.DoFlowAnalysis || !is_out || ec.CurrentBranching.IsAssigned (vi))
3910                                 return true;
3911
3912                         Report.Error (165, loc,
3913                                       "Use of unassigned parameter `" + name + "'");
3914                         return false;
3915                 }
3916
3917                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
3918                 {
3919                         if (!ec.DoFlowAnalysis || !is_out || ec.CurrentBranching.IsFieldAssigned (vi, field_name))
3920                                 return true;
3921
3922                         Report.Error (170, loc,
3923                                       "Use of possibly unassigned field `" + field_name + "'");
3924                         return false;
3925                 }
3926
3927                 public void SetAssigned (EmitContext ec)
3928                 {
3929                         if (is_out && ec.DoFlowAnalysis)
3930                                 ec.CurrentBranching.SetAssigned (vi);
3931                 }
3932
3933                 public void SetFieldAssigned (EmitContext ec, string field_name)
3934                 {
3935                         if (is_out && ec.DoFlowAnalysis)
3936                                 ec.CurrentBranching.SetFieldAssigned (vi, field_name);
3937                 }
3938
3939                 protected void DoResolveBase (EmitContext ec)
3940                 {
3941                         type = pars.GetParameterInfo (ec, idx, out mod);
3942                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3943                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3944                         eclass = ExprClass.Variable;
3945
3946                         if (is_out)
3947                                 vi = block.ParameterMap [idx];
3948
3949                         if (ec.CurrentAnonymousMethod != null){
3950                                 if (is_ref){
3951                                         Report.Error (1628, Location,
3952                                                       "Can not reference a ref or out parameter in an anonymous method");
3953                                         return;
3954                                 }
3955
3956                                 //
3957                                 // If we are referencing the parameter from the external block
3958                                 // flag it for capturing
3959                                 //
3960                                 //Console.WriteLine ("Is parameter `{0}' local? {1}", name, block.IsLocalParameter (name));
3961                                 if (!block.IsLocalParameter (name)){
3962                                         ec.CaptureParameter (name, type, idx);
3963                                 }
3964                         }
3965                 }
3966
3967                 //
3968                 // Notice that for ref/out parameters, the type exposed is not the
3969                 // same type exposed externally.
3970                 //
3971                 // for "ref int a":
3972                 //   externally we expose "int&"
3973                 //   here we expose       "int".
3974                 //
3975                 // We record this in "is_ref".  This means that the type system can treat
3976                 // the type as it is expected, but when we generate the code, we generate
3977                 // the alternate kind of code.
3978                 //
3979                 public override Expression DoResolve (EmitContext ec)
3980                 {
3981                         DoResolveBase (ec);
3982
3983                         if (is_out && ec.DoFlowAnalysis && !IsAssigned (ec, loc))
3984                                 return null;
3985
3986                         if (ec.RemapToProxy)
3987                                 return ec.RemapParameter (idx);
3988
3989                         return this;
3990                 }
3991
3992                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3993                 {
3994                         DoResolveBase (ec);
3995
3996                         SetAssigned (ec);
3997
3998                         if (ec.RemapToProxy)
3999                                 return ec.RemapParameterLValue (idx, right_side);
4000
4001                         return this;
4002                 }
4003
4004                 static public void EmitLdArg (ILGenerator ig, int x)
4005                 {
4006                         if (x <= 255){
4007                                 switch (x){
4008                                 case 0: ig.Emit (OpCodes.Ldarg_0); break;
4009                                 case 1: ig.Emit (OpCodes.Ldarg_1); break;
4010                                 case 2: ig.Emit (OpCodes.Ldarg_2); break;
4011                                 case 3: ig.Emit (OpCodes.Ldarg_3); break;
4012                                 default: ig.Emit (OpCodes.Ldarg_S, (byte) x); break;
4013                                 }
4014                         } else
4015                                 ig.Emit (OpCodes.Ldarg, x);
4016                 }
4017
4018                 //
4019                 // This method is used by parameters that are references, that are
4020                 // being passed as references:  we only want to pass the pointer (that
4021                 // is already stored in the parameter, not the address of the pointer,
4022                 // and not the value of the variable).
4023                 //
4024                 public void EmitLoad (EmitContext ec)
4025                 {
4026                         ILGenerator ig = ec.ig;
4027                         int arg_idx = idx;
4028
4029                         if (!ec.MethodIsStatic)
4030                                 arg_idx++;
4031
4032
4033                         EmitLdArg (ig, arg_idx);
4034
4035                         //
4036                         // FIXME: Review for anonymous methods
4037                         //
4038                 }
4039
4040                 public override void Emit (EmitContext ec)
4041                 {
4042                         if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
4043                                 ec.EmitParameter (name);
4044                                 return;
4045                         }
4046
4047                         Emit (ec, false);
4048                 }
4049
4050                 public void Emit (EmitContext ec, bool leave_copy)
4051                 {
4052                         ILGenerator ig = ec.ig;
4053                         int arg_idx = idx;
4054
4055                         if (!ec.MethodIsStatic)
4056                                 arg_idx++;
4057
4058                         EmitLdArg (ig, arg_idx);
4059
4060                         if (is_ref) {
4061                                 if (prepared)
4062                                         ec.ig.Emit (OpCodes.Dup);
4063
4064                                 //
4065                                 // If we are a reference, we loaded on the stack a pointer
4066                                 // Now lets load the real value
4067                                 //
4068                                 LoadFromPtr (ig, type);
4069                         }
4070
4071                         if (leave_copy) {
4072                                 ec.ig.Emit (OpCodes.Dup);
4073
4074                                 if (is_ref) {
4075                                         temp = new LocalTemporary (ec, type);
4076                                         temp.Store (ec);
4077                                 }
4078                         }
4079                 }
4080
4081                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4082                 {
4083                         if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
4084                                 ec.EmitAssignParameter (name, source, leave_copy, prepare_for_load);
4085                                 return;
4086                         }
4087
4088                         ILGenerator ig = ec.ig;
4089                         int arg_idx = idx;
4090
4091                         prepared = prepare_for_load;
4092
4093                         if (!ec.MethodIsStatic)
4094                                 arg_idx++;
4095
4096                         if (is_ref && !prepared)
4097                                 EmitLdArg (ig, arg_idx);
4098
4099                         source.Emit (ec);
4100
4101                         if (leave_copy)
4102                                 ec.ig.Emit (OpCodes.Dup);
4103
4104                         if (is_ref) {
4105                                 if (leave_copy) {
4106                                         temp = new LocalTemporary (ec, type);
4107                                         temp.Store (ec);
4108                                 }
4109
4110                                 StoreFromPtr (ig, type);
4111
4112                                 if (temp != null)
4113                                         temp.Emit (ec);
4114                         } else {
4115                                 if (arg_idx <= 255)
4116                                         ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
4117                                 else
4118                                         ig.Emit (OpCodes.Starg, arg_idx);
4119                         }
4120                 }
4121
4122                 public void AddressOf (EmitContext ec, AddressOp mode)
4123                 {
4124                         if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
4125                                 ec.EmitAddressOfParameter (name);
4126                                 return;
4127                         }
4128
4129                         int arg_idx = idx;
4130
4131                         if (!ec.MethodIsStatic)
4132                                 arg_idx++;
4133
4134                         if (is_ref){
4135                                 if (arg_idx <= 255)
4136                                         ec.ig.Emit (OpCodes.Ldarg_S, (byte) arg_idx);
4137                                 else
4138                                         ec.ig.Emit (OpCodes.Ldarg, arg_idx);
4139                         } else {
4140                                 if (arg_idx <= 255)
4141                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
4142                                 else
4143                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
4144                         }
4145                 }
4146
4147         }
4148
4149         /// <summary>
4150         ///   Used for arguments to New(), Invocation()
4151         /// </summary>
4152         public class Argument {
4153                 public enum AType : byte {
4154                         Expression,
4155                         Ref,
4156                         Out,
4157                         ArgList
4158                 };
4159
4160                 public readonly AType ArgType;
4161                 public Expression Expr;
4162
4163                 public Argument (Expression expr, AType type)
4164                 {
4165                         this.Expr = expr;
4166                         this.ArgType = type;
4167                 }
4168
4169                 public Argument (Expression expr)
4170                 {
4171                         this.Expr = expr;
4172                         this.ArgType = AType.Expression;
4173                 }
4174
4175                 public Type Type {
4176                         get {
4177                                 if (ArgType == AType.Ref || ArgType == AType.Out)
4178                                         return TypeManager.GetReferenceType (Expr.Type);
4179                                 else
4180                                         return Expr.Type;
4181                         }
4182                 }
4183
4184                 public Parameter.Modifier GetParameterModifier ()
4185                 {
4186                         switch (ArgType) {
4187                         case AType.Out:
4188                                 return Parameter.Modifier.OUT | Parameter.Modifier.ISBYREF;
4189
4190                         case AType.Ref:
4191                                 return Parameter.Modifier.REF | Parameter.Modifier.ISBYREF;
4192
4193                         default:
4194                                 return Parameter.Modifier.NONE;
4195                         }
4196                 }
4197
4198                 public static string FullDesc (Argument a)
4199                 {
4200                         if (a.ArgType == AType.ArgList)
4201                                 return "__arglist";
4202
4203                         return (a.ArgType == AType.Ref ? "ref " :
4204                                 (a.ArgType == AType.Out ? "out " : "")) +
4205                                 TypeManager.CSharpName (a.Expr.Type);
4206                 }
4207
4208                 public bool ResolveMethodGroup (EmitContext ec, Location loc)
4209                 {
4210                         ConstructedType ctype = Expr as ConstructedType;
4211                         if (ctype != null)
4212                                 Expr = ctype.GetSimpleName (ec);
4213
4214                         // FIXME: csc doesn't report any error if you try to use `ref' or
4215                         //        `out' in a delegate creation expression.
4216                         Expr = Expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
4217                         if (Expr == null)
4218                                 return false;
4219
4220                         return true;
4221                 }
4222
4223                 public bool Resolve (EmitContext ec, Location loc)
4224                 {
4225                         if (ArgType == AType.Ref) {
4226                                 Expr = Expr.Resolve (ec);
4227                                 if (Expr == null)
4228                                         return false;
4229
4230                                 if (!ec.IsConstructor) {
4231                                         FieldExpr fe = Expr as FieldExpr;
4232                                         if (fe != null && fe.FieldInfo.IsInitOnly) {
4233                                                 if (fe.FieldInfo.IsStatic)
4234                                                         Report.Error (199, loc, "A static readonly field cannot be passed ref or out (except in a static constructor)");
4235                                                 else
4236                                                         Report.Error (192, loc, "A readonly field cannot be passed ref or out (except in a constructor)");
4237                                                 return false;
4238                                         }
4239                                 }
4240                                 Expr = Expr.ResolveLValue (ec, Expr);
4241                         } else if (ArgType == AType.Out)
4242                                 Expr = Expr.ResolveLValue (ec, EmptyExpression.Null);
4243                         else
4244                                 Expr = Expr.Resolve (ec);
4245
4246                         if (Expr == null)
4247                                 return false;
4248
4249                         if (ArgType == AType.Expression)
4250                                 return true;
4251                         else {
4252                                 //
4253                                 // Catch errors where fields of a MarshalByRefObject are passed as ref or out
4254                                 // This is only allowed for `this'
4255                                 //
4256                                 FieldExpr fe = Expr as FieldExpr;
4257                                 if (fe != null && !fe.IsStatic){
4258                                         Expression instance = fe.InstanceExpression;
4259
4260                                         if (instance.GetType () != typeof (This)){
4261                                                 if (fe.InstanceExpression.Type.IsSubclassOf (TypeManager.mbr_type)){
4262                                                         Report.SymbolRelatedToPreviousError (fe.InstanceExpression.Type);
4263                                                         Report.Error (197, loc, "Cannot pass '{0}' as ref or out or take its address because it is a member of a marshal-by-reference class",
4264                                                                 fe.Name);
4265                                                         return false;
4266                                                 }
4267                                         }
4268                                 }
4269                         }
4270
4271                         if (Expr.eclass != ExprClass.Variable){
4272                                 //
4273                                 // We just probe to match the CSC output
4274                                 //
4275                                 if (Expr.eclass == ExprClass.PropertyAccess ||
4276                                     Expr.eclass == ExprClass.IndexerAccess){
4277                                         Report.Error (
4278                                                 206, loc,
4279                                                 "A property or indexer can not be passed as an out or ref " +
4280                                                 "parameter");
4281                                 } else {
4282                                         Report.Error (
4283                                                 1510, loc,
4284                                                 "An lvalue is required as an argument to out or ref");
4285                                 }
4286                                 return false;
4287                         }
4288
4289                         return true;
4290                 }
4291
4292                 public void Emit (EmitContext ec)
4293                 {
4294                         //
4295                         // Ref and Out parameters need to have their addresses taken.
4296                         //
4297                         // ParameterReferences might already be references, so we want
4298                         // to pass just the value
4299                         //
4300                         if (ArgType == AType.Ref || ArgType == AType.Out){
4301                                 AddressOp mode = AddressOp.Store;
4302
4303                                 if (ArgType == AType.Ref)
4304                                         mode |= AddressOp.Load;
4305
4306                                 if (Expr is ParameterReference){
4307                                         ParameterReference pr = (ParameterReference) Expr;
4308
4309                                         if (pr.IsRef)
4310                                                 pr.EmitLoad (ec);
4311                                         else {
4312
4313                                                 pr.AddressOf (ec, mode);
4314                                         }
4315                                 } else {
4316                                         if (Expr is IMemoryLocation)
4317                                                ((IMemoryLocation) Expr).AddressOf (ec, mode);
4318                                         else {
4319                                                 Report.Error (
4320                                                         1510, Expr.Location,
4321                                                         "An lvalue is required as an argument to out or ref");
4322                                                 return;
4323                                         }
4324                                 }
4325                         } else
4326                                 Expr.Emit (ec);
4327                 }
4328         }
4329
4330         /// <summary>
4331         ///   Invocation of methods or delegates.
4332         /// </summary>
4333         public class Invocation : ExpressionStatement {
4334                 public readonly ArrayList Arguments;
4335
4336                 Expression expr;
4337                 MethodBase method = null;
4338
4339                 //
4340                 // arguments is an ArrayList, but we do not want to typecast,
4341                 // as it might be null.
4342                 //
4343                 // FIXME: only allow expr to be a method invocation or a
4344                 // delegate invocation (7.5.5)
4345                 //
4346                 public Invocation (Expression expr, ArrayList arguments, Location l)
4347                 {
4348                         this.expr = expr;
4349                         Arguments = arguments;
4350                         loc = l;
4351                 }
4352
4353                 public Expression Expr {
4354                         get {
4355                                 return expr;
4356                         }
4357                 }
4358
4359                 /// <summary>
4360                 ///   Determines "better conversion" as specified in 7.4.2.3
4361                 ///
4362                 ///    Returns : p    if a->p is better,
4363                 ///              q    if a->q is better,
4364                 ///              null if neither is better
4365                 /// </summary>
4366                 static Type BetterConversion (EmitContext ec, Argument a, Type p, Type q, Location loc)
4367                 {
4368                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
4369                         Expression argument_expr = a.Expr;
4370
4371                         // p = TypeManager.TypeToCoreType (p);
4372                         // q = TypeManager.TypeToCoreType (q);
4373
4374                         if (argument_type == null)
4375                                 throw new Exception ("Expression of type " + a.Expr +
4376                                                      " does not resolve its type");
4377
4378                         if (p == null || q == null)
4379                                 throw new InternalErrorException ("BetterConversion Got a null conversion");
4380
4381                         if (p == q)
4382                                 return null;
4383
4384                         if (argument_expr is NullLiteral) {
4385                         //
4386                                 // If the argument is null and one of the types to compare is 'object' and
4387                                 // the other is a reference type, we prefer the other.
4388                         //
4389                                 // This follows from the usual rules:
4390                                 //   * There is an implicit conversion from 'null' to type 'object'
4391                                 //   * There is an implicit conversion from 'null' to any reference type
4392                                 //   * There is an implicit conversion from any reference type to type 'object'
4393                                 //   * There is no implicit conversion from type 'object' to other reference types
4394                                 //  => Conversion of 'null' to a reference type is better than conversion to 'object'
4395                                 //
4396                                 //  FIXME: This probably isn't necessary, since the type of a NullLiteral is the
4397                                 //         null type. I think it used to be 'object' and thus needed a special
4398                                 //         case to avoid the immediately following two checks.
4399                                 //
4400                                 if (!p.IsValueType && q == TypeManager.object_type)
4401                                         return p;
4402                                 if (!q.IsValueType && p == TypeManager.object_type)
4403                                         return q;
4404                         }
4405
4406                         if (argument_type == p)
4407                                 return p;
4408
4409                         if (argument_type == q)
4410                                 return q;
4411
4412                         Expression p_tmp = new EmptyExpression (p);
4413                         Expression q_tmp = new EmptyExpression (q);
4414
4415                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
4416                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
4417
4418                         if (p_to_q && !q_to_p)
4419                                 return p;
4420
4421                         if (q_to_p && !p_to_q)
4422                                 return q;
4423
4424                         if (p == TypeManager.sbyte_type)
4425                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
4426                                     q == TypeManager.uint32_type || q == TypeManager.uint64_type)
4427                                         return p;
4428                         if (q == TypeManager.sbyte_type)
4429                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
4430                                     p == TypeManager.uint32_type || p == TypeManager.uint64_type)
4431                                         return q;
4432
4433                         if (p == TypeManager.short_type)
4434                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
4435                                     q == TypeManager.uint64_type)
4436                                         return p;
4437
4438                         if (q == TypeManager.short_type)
4439                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
4440                                     p == TypeManager.uint64_type)
4441                                         return q;
4442
4443                         if (p == TypeManager.int32_type)
4444                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
4445                                         return p;
4446
4447                         if (q == TypeManager.int32_type)
4448                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
4449                                         return q;
4450
4451                         if (p == TypeManager.int64_type)
4452                                 if (q == TypeManager.uint64_type)
4453                                         return p;
4454                         if (q == TypeManager.int64_type)
4455                                 if (p == TypeManager.uint64_type)
4456                                         return q;
4457
4458                         return null;
4459                 }
4460
4461                 /// <summary>
4462                 ///   Determines "Better function" between candidate
4463                 ///   and the current best match
4464                 /// </summary>
4465                 /// <remarks>
4466                 ///    Returns a boolean indicating :
4467                 ///     false if candidate ain't better
4468                 ///     true  if candidate is better than the current best match
4469                 /// </remarks>
4470                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
4471                                            MethodBase candidate, bool candidate_params,
4472                                            MethodBase best, bool best_params, Location loc)
4473                 {
4474                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
4475                         ParameterData best_pd = TypeManager.GetParameterData (best);
4476
4477                         bool better_at_least_one = false;
4478                         bool same = true;
4479                         for (int j = 0; j < argument_count; ++j) {
4480                                 Argument a = (Argument) args [j];
4481
4482                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (j));
4483                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (j));
4484
4485                                 if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
4486                                         if (candidate_params)
4487                                                 ct = TypeManager.GetElementType (ct);
4488
4489                                 if (best_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
4490                                         if (best_params)
4491                                                 bt = TypeManager.GetElementType (bt);
4492
4493                                 if (ct.Equals (bt))
4494                                         continue;
4495
4496                                 same = false;
4497                                 Type better = BetterConversion (ec, a, ct, bt, loc);
4498                                 // for each argument, the conversion to 'ct' should be no worse than
4499                                 // the conversion to 'bt'.
4500                                 if (better == bt)
4501                                         return false;
4502
4503                                 // for at least one argument, the conversion to 'ct' should be better than
4504                                 // the conversion to 'bt'.
4505                                 if (better == ct)
4506                                         better_at_least_one = true;
4507                         }
4508
4509                         if (better_at_least_one)
4510                                 return true;
4511
4512                         if (!same)
4513                                 return false;
4514
4515                         //
4516                         // If two methods have equal parameter types, but
4517                         // only one of them is generic, the non-generic one wins.
4518                         //
4519                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
4520                                 return true;
4521                         else if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
4522                                 return false;
4523
4524                         //
4525                         // Note that this is not just an optimization.  This handles the case
4526                         //
4527                         //   Add (float f1, float f2, float f3);
4528                         //   Add (params decimal [] foo);
4529                         //
4530                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
4531                         // first candidate would've chosen as better.
4532                         //
4533                         if (candidate_params == best_params) {
4534                                 //
4535                                 // We need to handle the case of a virtual function and its override.
4536                                 // The override is ignored during 'applicable_type' calculation.  However,
4537                                 // it should be chosen over the base virtual function, especially when handling
4538                                 // value types.
4539                                 //
4540                                 return IsAncestralType (best.DeclaringType, candidate.DeclaringType);
4541                         }
4542
4543                         //
4544                         // This handles the following cases:
4545                         //
4546                         //   Trim () is better than Trim (params char[] chars)
4547                         //   Concat (string s1, string s2, string s3) is better than
4548                         //     Concat (string s1, params string [] srest)
4549                         //
4550                         return !candidate_params && best_params;
4551                 }
4552
4553                 public static string FullMethodDesc (MethodBase mb)
4554                 {
4555                         string ret_type = "";
4556
4557                         if (mb == null)
4558                                 return "";
4559
4560                         if (mb is MethodInfo)
4561                                 ret_type = TypeManager.CSharpName (((MethodInfo) mb).ReturnType);
4562
4563                         StringBuilder sb = new StringBuilder (ret_type);
4564                         sb.Append (" ");
4565                         sb.Append (mb.ReflectedType.ToString ());
4566                         sb.Append (".");
4567                         sb.Append (mb.Name);
4568
4569                         ParameterData pd = TypeManager.GetParameterData (mb);
4570
4571                         int count = pd.Count;
4572                         sb.Append (" (");
4573
4574                         for (int i = count; i > 0; ) {
4575                                 i--;
4576
4577                                 sb.Append (pd.ParameterDesc (count - i - 1));
4578                                 if (i != 0)
4579                                         sb.Append (", ");
4580                         }
4581
4582                         sb.Append (")");
4583                         return sb.ToString ();
4584                 }
4585
4586                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
4587                 {
4588                         MemberInfo [] miset;
4589                         MethodGroupExpr union;
4590
4591                         if (mg1 == null) {
4592                                 if (mg2 == null)
4593                                         return null;
4594                                 return (MethodGroupExpr) mg2;
4595                         } else {
4596                                 if (mg2 == null)
4597                                         return (MethodGroupExpr) mg1;
4598                         }
4599
4600                         MethodGroupExpr left_set = null, right_set = null;
4601                         int length1 = 0, length2 = 0;
4602
4603                         left_set = (MethodGroupExpr) mg1;
4604                         length1 = left_set.Methods.Length;
4605
4606                         right_set = (MethodGroupExpr) mg2;
4607                         length2 = right_set.Methods.Length;
4608
4609                         ArrayList common = new ArrayList ();
4610
4611                         foreach (MethodBase r in right_set.Methods){
4612                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
4613                                         common.Add (r);
4614                         }
4615
4616                         miset = new MemberInfo [length1 + length2 - common.Count];
4617                         left_set.Methods.CopyTo (miset, 0);
4618
4619                         int k = length1;
4620
4621                         foreach (MethodBase r in right_set.Methods) {
4622                                 if (!common.Contains (r))
4623                                         miset [k++] = r;
4624                         }
4625
4626                         union = new MethodGroupExpr (miset, loc);
4627
4628                         return union;
4629                 }
4630
4631                 static bool IsParamsMethodApplicable (EmitContext ec, MethodGroupExpr me,
4632                                                       ArrayList arguments, int arg_count,
4633                                                       ref MethodBase candidate)
4634                 {
4635                         return IsParamsMethodApplicable (
4636                                 ec, me, arguments, arg_count, false, ref candidate) ||
4637                                 IsParamsMethodApplicable (
4638                                         ec, me, arguments, arg_count, true, ref candidate);
4639
4640
4641                 }
4642
4643                 static bool IsParamsMethodApplicable (EmitContext ec, MethodGroupExpr me,
4644                                                       ArrayList arguments, int arg_count,
4645                                                       bool do_varargs, ref MethodBase candidate)
4646                 {
4647                         if (!me.HasTypeArguments &&
4648                             !TypeManager.InferParamsTypeArguments (ec, arguments, ref candidate))
4649                                 return false;
4650
4651                         return IsParamsMethodApplicable (
4652                                 ec, arguments, arg_count, candidate, do_varargs);
4653                 }
4654
4655                 /// <summary>
4656                 ///   Determines if the candidate method, if a params method, is applicable
4657                 ///   in its expanded form to the given set of arguments
4658                 /// </summary>
4659                 static bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments,
4660                                                       int arg_count, MethodBase candidate,
4661                                                       bool do_varargs)
4662                 {
4663                         ParameterData pd = TypeManager.GetParameterData (candidate);
4664
4665                         int pd_count = pd.Count;
4666
4667                         if (pd_count == 0)
4668                                 return false;
4669
4670                         int count = pd_count - 1;
4671                         if (do_varargs) {
4672                                 if (pd.ParameterModifier (count) != Parameter.Modifier.ARGLIST)
4673                                         return false;
4674                                 if (pd_count != arg_count)
4675                                         return false;
4676                         } else {
4677                                 if (pd.ParameterModifier (count) != Parameter.Modifier.PARAMS)
4678                                 return false;
4679                         }
4680
4681                         if (count > arg_count)
4682                                 return false;
4683
4684                         if (pd_count == 1 && arg_count == 0)
4685                                 return true;
4686
4687                         //
4688                         // If we have come this far, the case which
4689                         // remains is when the number of parameters is
4690                         // less than or equal to the argument count.
4691                         //
4692                         for (int i = 0; i < count; ++i) {
4693
4694                                 Argument a = (Argument) arguments [i];
4695
4696                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
4697                                         (unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF)));
4698                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
4699                                         (unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF)));
4700
4701                                 if (a_mod == p_mod) {
4702
4703                                         if (a_mod == Parameter.Modifier.NONE)
4704                                                 if (!Convert.ImplicitConversionExists (ec,
4705                                                                                        a.Expr,
4706                                                                                        pd.ParameterType (i)))
4707                                                         return false;
4708
4709                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
4710                                                 Type pt = pd.ParameterType (i);
4711
4712                                                 if (!pt.IsByRef)
4713                                                         pt = TypeManager.GetReferenceType (pt);
4714
4715                                                 if (pt != a.Type)
4716                                                         return false;
4717                                         }
4718                                 } else
4719                                         return false;
4720
4721                         }
4722
4723                         if (do_varargs) {
4724                                 Argument a = (Argument) arguments [count];
4725                                 if (!(a.Expr is Arglist))
4726                                         return false;
4727
4728                                 return true;
4729                         }
4730
4731                         Type element_type = TypeManager.GetElementType (pd.ParameterType (pd_count - 1));
4732
4733                         for (int i = pd_count - 1; i < arg_count; i++) {
4734                                 Argument a = (Argument) arguments [i];
4735
4736                                 if (!Convert.ImplicitConversionExists (ec, a.Expr, element_type))
4737                                         return false;
4738                         }
4739
4740                         return true;
4741                 }
4742
4743                 static bool IsApplicable (EmitContext ec, MethodGroupExpr me,
4744                                           ArrayList arguments, int arg_count,
4745                                           ref MethodBase candidate)
4746                 {
4747                         if (!me.HasTypeArguments &&
4748                             !TypeManager.InferTypeArguments (ec, arguments, ref candidate))
4749                                 return false;
4750
4751                         return IsApplicable (ec, arguments, arg_count, candidate);
4752                 }
4753
4754                 /// <summary>
4755                 ///   Determines if the candidate method is applicable (section 14.4.2.1)
4756                 ///   to the given set of arguments
4757                 /// </summary>
4758                 static bool IsApplicable (EmitContext ec, ArrayList arguments, int arg_count,
4759                                           MethodBase candidate)
4760                 {
4761                         ParameterData pd = TypeManager.GetParameterData (candidate);
4762
4763                         if (arg_count != pd.Count)
4764                                 return false;
4765
4766                         for (int i = arg_count; i > 0; ) {
4767                                 i--;
4768
4769                                 Argument a = (Argument) arguments [i];
4770
4771                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
4772                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
4773                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
4774                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
4775
4776
4777                                 if (a_mod == p_mod ||
4778                                     (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
4779                                         if (a_mod == Parameter.Modifier.NONE) {
4780                                                 if (!Convert.ImplicitConversionExists (ec,
4781                                                                                        a.Expr,
4782                                                                                        pd.ParameterType (i)))
4783                                                         return false;
4784                                         }
4785
4786                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
4787                                                 Type pt = pd.ParameterType (i);
4788
4789                                                 if (!pt.IsByRef)
4790                                                         pt = TypeManager.GetReferenceType (pt);
4791
4792                                                 if (pt != a.Type)
4793                                                         return false;
4794                                         }
4795                                 } else
4796                                         return false;
4797                         }
4798
4799                         return true;
4800                 }
4801
4802                 static private bool IsAncestralType (Type first_type, Type second_type)
4803                 {
4804                         return first_type != second_type &&
4805                                 (second_type.IsSubclassOf (first_type) ||
4806                                  TypeManager.ImplementsInterface (second_type, first_type));
4807                 }
4808
4809                 /// <summary>
4810                 ///   Find the Applicable Function Members (7.4.2.1)
4811                 ///
4812                 ///   me: Method Group expression with the members to select.
4813                 ///       it might contain constructors or methods (or anything
4814                 ///       that maps to a method).
4815                 ///
4816                 ///   Arguments: ArrayList containing resolved Argument objects.
4817                 ///
4818                 ///   loc: The location if we want an error to be reported, or a Null
4819                 ///        location for "probing" purposes.
4820                 ///
4821                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4822                 ///            that is the best match of me on Arguments.
4823                 ///
4824                 /// </summary>
4825                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
4826                                                           ArrayList Arguments, bool may_fail,
4827                                                           Location loc)
4828                 {
4829                         MethodBase method = null;
4830                         bool method_params = false;
4831                         Type applicable_type = null;
4832                         int arg_count = 0;
4833                         ArrayList candidates = new ArrayList ();
4834
4835                         //
4836                         // Used to keep a map between the candidate
4837                         // and whether it is being considered in its
4838                         // normal or expanded form
4839                         //
4840                         // false is normal form, true is expanded form
4841                         //
4842                         Hashtable candidate_to_form = null;
4843
4844                         if (Arguments != null)
4845                                 arg_count = Arguments.Count;
4846
4847                         if ((me.Name == "Invoke") &&
4848                             TypeManager.IsDelegateType (me.DeclaringType)) {
4849                                 Error_InvokeOnDelegate (loc);
4850                                 return null;
4851                         }
4852
4853                         MethodBase[] methods = me.Methods;
4854
4855                         //
4856                         // First we construct the set of applicable methods
4857                         //
4858                         bool is_sorted = true;
4859                         for (int i = 0; i < methods.Length; i++){
4860                                 Type decl_type = methods [i].DeclaringType;
4861
4862                                 //
4863                                 // If we have already found an applicable method
4864                                 // we eliminate all base types (Section 14.5.5.1)
4865                                 //
4866                                 if ((applicable_type != null) &&
4867                                     IsAncestralType (decl_type, applicable_type))
4868                                         continue;
4869
4870                                 //
4871                                 // Check if candidate is applicable (section 14.4.2.1)
4872                                 //   Is candidate applicable in normal form?
4873                                 //
4874                                 bool is_applicable = IsApplicable (
4875                                         ec, me, Arguments, arg_count, ref methods [i]);
4876
4877                                 if (!is_applicable &&
4878                                     (IsParamsMethodApplicable (
4879                                             ec, me, Arguments, arg_count, ref methods [i]))) {
4880                                         MethodBase candidate = methods [i];
4881                                         if (candidate_to_form == null)
4882                                                 candidate_to_form = new PtrHashtable ();
4883                                         candidate_to_form [candidate] = candidate;
4884                                         // Candidate is applicable in expanded form
4885                                         is_applicable = true;
4886                                 }
4887
4888                                 if (!is_applicable)
4889                                         continue;
4890
4891                                 candidates.Add (methods [i]);
4892
4893                                 //
4894                                 // Methods marked 'override' don't take part in 'applicable_type'
4895                                 // computation.
4896                                 //
4897                                 if (!me.IsBase &&
4898                                     methods [i].IsVirtual &&
4899                                     (methods [i].Attributes & MethodAttributes.NewSlot) == 0)
4900                                         continue;
4901
4902                                 if (applicable_type == null)
4903                                         applicable_type = decl_type;
4904                                 else if (applicable_type != decl_type) {
4905                                         is_sorted = false;
4906                                         if (IsAncestralType (applicable_type, decl_type))
4907                                                 applicable_type = decl_type;
4908                                 }
4909                         }
4910
4911                         int candidate_top = candidates.Count;
4912
4913                         if (applicable_type == null) {
4914                                 //
4915                                 // Okay so we have failed to find anything so we
4916                                 // return by providing info about the closest match
4917                                 //
4918                                 for (int i = 0; i < methods.Length; ++i) {
4919                                         MethodBase c = (MethodBase) methods [i];
4920                                         ParameterData pd = TypeManager.GetParameterData (c);
4921
4922                                         if (pd.Count != arg_count)
4923                                                 continue;
4924
4925                                         if (!TypeManager.InferTypeArguments (ec, Arguments, ref c))
4926                                                 continue;
4927
4928                                         VerifyArgumentsCompat (ec, Arguments, arg_count,
4929                                                                c, false, null, may_fail, loc);
4930                                         break;
4931                                 }
4932
4933                                 if (!may_fail) {
4934                                         string report_name = me.Name;
4935                                         if (report_name == ".ctor")
4936                                                 report_name = me.DeclaringType.ToString ();
4937
4938                                         for (int i = 0; i < methods.Length; ++i) {
4939                                                 MethodBase c = methods [i];
4940                                                 ParameterData pd = TypeManager.GetParameterData (c);
4941
4942                                                 if (pd.Count != arg_count)
4943                                                         continue;
4944
4945                                                 if (TypeManager.InferTypeArguments (ec, Arguments, ref c))
4946                                                         continue;
4947
4948                                                 Report.Error (
4949                                                         411, loc, "The type arguments for " +
4950                                                         "method `{0}' cannot be infered from " +
4951                                                         "the usage. Try specifying the type " +
4952                                                         "arguments explicitly.", report_name);
4953                                                 return null;
4954                                         }
4955
4956                                         Error_WrongNumArguments (
4957                                                 loc, report_name, arg_count);
4958                                         return null;
4959                                 }
4960
4961                                 return null;
4962                         }
4963
4964                         if (!is_sorted) {
4965                                 //
4966                                 // At this point, applicable_type is _one_ of the most derived types
4967                                 // in the set of types containing the methods in this MethodGroup.
4968                                 // Filter the candidates so that they only contain methods from the
4969                                 // most derived types.
4970                                 //
4971
4972                                 int finalized = 0; // Number of finalized candidates
4973
4974                                 do {
4975                                         // Invariant: applicable_type is a most derived type
4976
4977                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4978                                         // eliminating all it's base types.  At the same time, we'll also move
4979                                         // every unrelated type to the end of the array, and pick the next
4980                                         // 'applicable_type'.
4981
4982                                         Type next_applicable_type = null;
4983                                         int j = finalized; // where to put the next finalized candidate
4984                                         int k = finalized; // where to put the next undiscarded candidate
4985                                         for (int i = finalized; i < candidate_top; ++i) {
4986                                                 MethodBase candidate = (MethodBase) candidates [i];
4987                                                 Type decl_type = candidate.DeclaringType;
4988
4989                                                 if (decl_type == applicable_type) {
4990                                                         candidates [k++] = candidates [j];
4991                                                         candidates [j++] = candidates [i];
4992                                                         continue;
4993                                                 }
4994
4995                                                 if (IsAncestralType (decl_type, applicable_type))
4996                                                         continue;
4997
4998                                                 if (next_applicable_type != null &&
4999                                                     IsAncestralType (decl_type, next_applicable_type))
5000                                                         continue;
5001
5002                                                 candidates [k++] = candidates [i];
5003
5004 #if false
5005                                                 //
5006                                                 // Methods marked 'override' don't take part in 'applicable_type'
5007                                                 // computation.
5008                                                 //
5009                                                 if (!me.IsBase &&
5010                                                     candidate.IsVirtual &&
5011                                                     (candidate.Attributes & MethodAttributes.NewSlot) == 0)
5012                                                         continue;
5013 #endif
5014
5015                                                 if (next_applicable_type == null ||
5016                                                     IsAncestralType (next_applicable_type, decl_type))
5017                                                         next_applicable_type = decl_type;
5018                                         }
5019
5020                                         applicable_type = next_applicable_type;
5021                                         finalized = j;
5022                                         candidate_top = k;
5023                                 } while (applicable_type != null);
5024                         }
5025
5026                         //
5027                         // Now we actually find the best method
5028                         //
5029
5030                         method = (MethodBase) candidates [0];
5031                         method_params = candidate_to_form != null && candidate_to_form.Contains (method);
5032                         for (int ix = 1; ix < candidate_top; ix++){
5033                                 MethodBase candidate = (MethodBase) candidates [ix];
5034
5035                                 if (candidate == method)
5036                                         continue;
5037
5038                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
5039
5040                                 if (BetterFunction (ec, Arguments, arg_count,
5041                                                     candidate, cand_params,
5042                                                     method, method_params, loc)) {
5043                                         method = candidate;
5044                                         method_params = cand_params;
5045                                 }
5046                         }
5047
5048                         //
5049                         // Now check that there are no ambiguities i.e the selected method
5050                         // should be better than all the others
5051                         //
5052                         bool ambiguous = false;
5053                         for (int ix = 0; ix < candidate_top; ix++){
5054                                 MethodBase candidate = (MethodBase) candidates [ix];
5055
5056                                 if (candidate == method)
5057                                         continue;
5058
5059                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
5060                                 if (!BetterFunction (ec, Arguments, arg_count,
5061                                                     method, method_params,
5062                                                     candidate, cand_params,
5063                                                      loc)) {
5064                                         Report.SymbolRelatedToPreviousError (candidate);
5065                                         ambiguous = true;
5066                                 }
5067                         }
5068
5069                         if (ambiguous) {
5070                                 Report.SymbolRelatedToPreviousError (method);
5071                                 Report.Error (121, loc, "Ambiguous call when selecting function due to implicit casts");
5072                                 return null;
5073                         }
5074
5075                         //
5076                         // And now check if the arguments are all
5077                         // compatible, perform conversions if
5078                         // necessary etc. and return if everything is
5079                         // all right
5080                         //
5081                         if (!VerifyArgumentsCompat (ec, Arguments, arg_count, method,
5082                                                     method_params, null, may_fail, loc))
5083                                 return null;
5084
5085                         return method;
5086                 }
5087
5088                 static void Error_WrongNumArguments (Location loc, String name, int arg_count)
5089                 {
5090                         Report.Error (1501, loc,
5091                                       "No overload for method `" + name + "' takes `" +
5092                                       arg_count + "' arguments");
5093                 }
5094
5095                 static void Error_InvokeOnDelegate (Location loc)
5096                 {
5097                         Report.Error (1533, loc,
5098                                       "Invoke cannot be called directly on a delegate");
5099                 }
5100
5101                 static void Error_InvalidArguments (Location loc, int idx, MethodBase method,
5102                                                     Type delegate_type, string arg_sig, string par_desc)
5103                 {
5104                         if (delegate_type == null)
5105                                 Report.Error (1502, loc,
5106                                               "The best overloaded match for method '" +
5107                                               FullMethodDesc (method) +
5108                                               "' has some invalid arguments");
5109                         else
5110                                 Report.Error (1594, loc,
5111                                               "Delegate '" + delegate_type.ToString () +
5112                                               "' has some invalid arguments.");
5113                         Report.Error (1503, loc,
5114                                       String.Format ("Argument {0}: Cannot convert from '{1}' to '{2}'",
5115                                                      idx, arg_sig, par_desc));
5116                 }
5117
5118                 public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
5119                                                           int arg_count, MethodBase method,
5120                                                           bool chose_params_expanded,
5121                                                           Type delegate_type, bool may_fail,
5122                                                           Location loc)
5123                 {
5124                         ParameterData pd = TypeManager.GetParameterData (method);
5125                         int pd_count = pd.Count;
5126
5127                         for (int j = 0; j < arg_count; j++) {
5128                                 Argument a = (Argument) Arguments [j];
5129                                 Expression a_expr = a.Expr;
5130                                 Type parameter_type = pd.ParameterType (j);
5131                                 Parameter.Modifier pm = pd.ParameterModifier (j);
5132
5133                                 if (pm == Parameter.Modifier.PARAMS){
5134                                         if ((pm & ~Parameter.Modifier.PARAMS) != a.GetParameterModifier ()) {
5135                                                 if (!may_fail)
5136                                                         Error_InvalidArguments (
5137                                                                 loc, j, method, delegate_type,
5138                                                                 Argument.FullDesc (a), pd.ParameterDesc (j));
5139                                                 return false;
5140                                         }
5141
5142                                         if (chose_params_expanded)
5143                                                 parameter_type = TypeManager.GetElementType (parameter_type);
5144                                 } else if (pm == Parameter.Modifier.ARGLIST){
5145                                         continue;
5146                                 } else {
5147                                         //
5148                                         // Check modifiers
5149                                         //
5150                                         if (pd.ParameterModifier (j) != a.GetParameterModifier ()){
5151                                                 if (!may_fail)
5152                                                         Error_InvalidArguments (
5153                                                                 loc, j, method, delegate_type,
5154                                                                 Argument.FullDesc (a), pd.ParameterDesc (j));
5155                                                 return false;
5156                                         }
5157                                 }
5158
5159                                 //
5160                                 // Check Type
5161                                 //
5162                                 if (!TypeManager.IsEqual (a.Type, parameter_type)){
5163                                         Expression conv;
5164
5165                                         conv = Convert.ImplicitConversion (ec, a_expr, parameter_type, loc);
5166
5167                                         if (conv == null) {
5168                                                 if (!may_fail)
5169                                                         Error_InvalidArguments (
5170                                                                 loc, j, method, delegate_type,
5171                                                                 Argument.FullDesc (a), pd.ParameterDesc (j));
5172                                                 return false;
5173                                         }
5174
5175                                         //
5176                                         // Update the argument with the implicit conversion
5177                                         //
5178                                         if (a_expr != conv)
5179                                                 a.Expr = conv;
5180                                 }
5181
5182                                 if (parameter_type.IsPointer){
5183                                         if (!ec.InUnsafe){
5184                                                 UnsafeError (loc);
5185                                                 return false;
5186                                         }
5187                                 }
5188
5189                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
5190                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
5191                                 Parameter.Modifier p_mod = pd.ParameterModifier (j) &
5192                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
5193
5194                                 if (a_mod != p_mod &&
5195                                     pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
5196                                         if (!may_fail) {
5197                                                 Report.Error (1502, loc,
5198                                                        "The best overloaded match for method '" + FullMethodDesc (method)+
5199                                                        "' has some invalid arguments");
5200                                                 Report.Error (1503, loc,
5201                                                        "Argument " + (j+1) +
5202                                                        ": Cannot convert from '" + Argument.FullDesc (a)
5203                                                        + "' to '" + pd.ParameterDesc (j) + "'");
5204                                         }
5205
5206                                         return false;
5207                                 }
5208                         }
5209
5210                         return true;
5211                 }
5212
5213                 public override Expression DoResolve (EmitContext ec)
5214                 {
5215                         //
5216                         // First, resolve the expression that is used to
5217                         // trigger the invocation
5218                         //
5219                         if (expr is ConstructedType)
5220                                 expr = ((ConstructedType) expr).GetSimpleName (ec);
5221
5222                         expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
5223                         if (expr == null)
5224                                 return null;
5225
5226                         if (!(expr is MethodGroupExpr)) {
5227                                 Type expr_type = expr.Type;
5228
5229                                 if (expr_type != null){
5230                                         bool IsDelegate = TypeManager.IsDelegateType (expr_type);
5231                                         if (IsDelegate)
5232                                                 return (new DelegateInvocation (
5233                                                         this.expr, Arguments, loc)).Resolve (ec);
5234                                 }
5235                         }
5236
5237                         if (!(expr is MethodGroupExpr)){
5238                                 expr.Error_UnexpectedKind (ResolveFlags.MethodGroup, loc);
5239                                 return null;
5240                         }
5241
5242                         //
5243                         // Next, evaluate all the expressions in the argument list
5244                         //
5245                         if (Arguments != null){
5246                                 foreach (Argument a in Arguments){
5247                                         if (!a.Resolve (ec, loc))
5248                                                 return null;
5249                                 }
5250                         }
5251
5252                         MethodGroupExpr mg = (MethodGroupExpr) expr;
5253                         method = OverloadResolve (ec, mg, Arguments, false, loc);
5254
5255                         if (method == null)
5256                                 return null;
5257
5258                         MethodInfo mi = method as MethodInfo;
5259                         if (mi != null) {
5260                                 type = TypeManager.TypeToCoreType (mi.ReturnType);
5261                                 if (!mi.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null)) {
5262                                         SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
5263                                         return null;
5264                                 }
5265
5266                                 Expression iexpr = mg.InstanceExpression;
5267                                 if (mi.IsStatic && (iexpr != null) && !(iexpr is This)) {
5268                                         if (mg.IdenticalTypeName)
5269                                                 mg.InstanceExpression = null;
5270                                         else {
5271                                                 MemberAccess.error176 (loc, mi.Name);
5272                                                 return null;
5273                                         }
5274                                 }
5275                         }
5276
5277                         if (type.IsPointer){
5278                                 if (!ec.InUnsafe){
5279                                         UnsafeError (loc);
5280                                         return null;
5281                                 }
5282                         }
5283
5284                         //
5285                         // Only base will allow this invocation to happen.
5286                         //
5287                         if (mg.IsBase && method.IsAbstract){
5288                                 Report.Error (205, loc, "Cannot call an abstract base member: " +
5289                                               FullMethodDesc (method));
5290                                 return null;
5291                         }
5292
5293                         if (method.Name == "Finalize" && Arguments == null) {
5294                                 if (mg.IsBase)
5295                                         Report.Error (250, loc, "Do not directly call your base class Finalize method. It is called automatically from your destructor");
5296                                 else
5297                                         Report.Error (245, loc, "Destructors and object.Finalize cannot be called directly. Consider calling IDisposable.Dispose if available");
5298                                 return null;
5299                         }
5300
5301                         if ((method.Attributes & MethodAttributes.SpecialName) != 0){
5302                                 if (TypeManager.LookupDeclSpace (method.DeclaringType) != null || TypeManager.IsSpecialMethod (method)) {
5303                                         Report.Error (571, loc, TypeManager.CSharpSignature (method) + ": can not call operator or accessor");
5304                                         return null;
5305                                 }
5306                         }
5307
5308                         if (mg.InstanceExpression != null)
5309                                 mg.InstanceExpression.CheckMarshallByRefAccess (ec.ContainerType);
5310
5311                         eclass = ExprClass.Value;
5312                         return this;
5313                 }
5314
5315                 // <summary>
5316                 //   Emits the list of arguments as an array
5317                 // </summary>
5318                 static void EmitParams (EmitContext ec, int idx, ArrayList arguments)
5319                 {
5320                         ILGenerator ig = ec.ig;
5321                         int count = arguments.Count - idx;
5322                         Argument a = (Argument) arguments [idx];
5323                         Type t = a.Expr.Type;
5324
5325                         IntConstant.EmitInt (ig, count);
5326                         ig.Emit (OpCodes.Newarr, TypeManager.TypeToCoreType (t));
5327
5328                         int top = arguments.Count;
5329                         for (int j = idx; j < top; j++){
5330                                 a = (Argument) arguments [j];
5331
5332                                 ig.Emit (OpCodes.Dup);
5333                                 IntConstant.EmitInt (ig, j - idx);
5334
5335                                 bool is_stobj, has_type_arg;
5336                                 OpCode op = ArrayAccess.GetStoreOpcode (t, out is_stobj, out has_type_arg);
5337                                 if (is_stobj)
5338                                         ig.Emit (OpCodes.Ldelema, t);
5339
5340                                 a.Emit (ec);
5341
5342                                 if (has_type_arg)
5343                                         ig.Emit (op, t);
5344                                 else
5345                                         ig.Emit (op);
5346                         }
5347                 }
5348
5349                 /// <summary>
5350                 ///   Emits a list of resolved Arguments that are in the arguments
5351                 ///   ArrayList.
5352                 ///
5353                 ///   The MethodBase argument might be null if the
5354                 ///   emission of the arguments is known not to contain
5355                 ///   a `params' field (for example in constructors or other routines
5356                 ///   that keep their arguments in this structure)
5357                 ///
5358                 ///   if `dup_args' is true, a copy of the arguments will be left
5359                 ///   on the stack. If `dup_args' is true, you can specify `this_arg'
5360                 ///   which will be duplicated before any other args. Only EmitCall
5361                 ///   should be using this interface.
5362                 /// </summary>
5363                 public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments, bool dup_args, LocalTemporary this_arg)
5364                 {
5365                         ParameterData pd;
5366                         if (mb != null)
5367                                 pd = TypeManager.GetParameterData (mb);
5368                         else
5369                                 pd = null;
5370
5371                         LocalTemporary [] temps = null;
5372
5373                         if (dup_args)
5374                                 temps = new LocalTemporary [arguments.Count];
5375
5376                         //
5377                         // If we are calling a params method with no arguments, special case it
5378                         //
5379                         if (arguments == null){
5380                                 if (pd != null && pd.Count > 0 &&
5381                                     pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
5382                                         ILGenerator ig = ec.ig;
5383
5384                                         IntConstant.EmitInt (ig, 0);
5385                                         ig.Emit (OpCodes.Newarr, TypeManager.GetElementType (pd.ParameterType (0)));
5386                                 }
5387
5388                                 return;
5389                         }
5390
5391                         int top = arguments.Count;
5392
5393                         for (int i = 0; i < top; i++){
5394                                 Argument a = (Argument) arguments [i];
5395
5396                                 if (pd != null){
5397                                         if (pd.ParameterModifier (i) == Parameter.Modifier.PARAMS){
5398                                                 //
5399                                                 // Special case if we are passing the same data as the
5400                                                 // params argument, do not put it in an array.
5401                                                 //
5402                                                 if (pd.ParameterType (i) == a.Type)
5403                                                         a.Emit (ec);
5404                                                 else
5405                                                         EmitParams (ec, i, arguments);
5406                                                 return;
5407                                         }
5408                                 }
5409
5410                                 a.Emit (ec);
5411                                 if (dup_args) {
5412                                         ec.ig.Emit (OpCodes.Dup);
5413                                         (temps [i] = new LocalTemporary (ec, a.Type)).Store (ec);
5414                                 }
5415                         }
5416
5417                         if (dup_args) {
5418                                 if (this_arg != null)
5419                                         this_arg.Emit (ec);
5420
5421                                 for (int i = 0; i < top; i ++)
5422                                         temps [i].Emit (ec);
5423                         }
5424
5425                         if (pd != null && pd.Count > top &&
5426                             pd.ParameterModifier (top) == Parameter.Modifier.PARAMS){
5427                                 ILGenerator ig = ec.ig;
5428
5429                                 IntConstant.EmitInt (ig, 0);
5430                                 ig.Emit (OpCodes.Newarr, TypeManager.GetElementType (pd.ParameterType (top)));
5431                         }
5432                 }
5433
5434                 static Type[] GetVarargsTypes (EmitContext ec, MethodBase mb,
5435                                                ArrayList arguments)
5436                 {
5437                         ParameterData pd = TypeManager.GetParameterData (mb);
5438
5439                         if (arguments == null)
5440                                 return new Type [0];
5441
5442                         Argument a = (Argument) arguments [pd.Count - 1];
5443                         Arglist list = (Arglist) a.Expr;
5444
5445                         return list.ArgumentTypes;
5446                 }
5447
5448                 /// <summary>
5449                 /// This checks the ConditionalAttribute on the method
5450                 /// </summary>
5451                 static bool IsMethodExcluded (MethodBase method, EmitContext ec)
5452                 {
5453                         if (method.IsConstructor)
5454                                 return false;
5455
5456                         IMethodData md = TypeManager.GetMethod (method);
5457                         if (md != null)
5458                                 return md.IsExcluded (ec);
5459
5460                         // For some methods (generated by delegate class) GetMethod returns null
5461                         // because they are not included in builder_to_method table
5462                         if (method.DeclaringType is TypeBuilder)
5463                                 return false;
5464
5465                         return AttributeTester.IsConditionalMethodExcluded (method);
5466                 }
5467
5468                 /// <remarks>
5469                 ///   is_base tells whether we want to force the use of the `call'
5470                 ///   opcode instead of using callvirt.  Call is required to call
5471                 ///   a specific method, while callvirt will always use the most
5472                 ///   recent method in the vtable.
5473                 ///
5474                 ///   is_static tells whether this is an invocation on a static method
5475                 ///
5476                 ///   instance_expr is an expression that represents the instance
5477                 ///   it must be non-null if is_static is false.
5478                 ///
5479                 ///   method is the method to invoke.
5480                 ///
5481                 ///   Arguments is the list of arguments to pass to the method or constructor.
5482                 /// </remarks>
5483                 public static void EmitCall (EmitContext ec, bool is_base,
5484                                              bool is_static, Expression instance_expr,
5485                                              MethodBase method, ArrayList Arguments, Location loc)
5486                 {
5487                         EmitCall (ec, is_base, is_static, instance_expr, method, Arguments, loc, false, false);
5488                 }
5489
5490                 // `dup_args' leaves an extra copy of the arguments on the stack
5491                 // `omit_args' does not leave any arguments at all.
5492                 // So, basically, you could make one call with `dup_args' set to true,
5493                 // and then another with `omit_args' set to true, and the two calls
5494                 // would have the same set of arguments. However, each argument would
5495                 // only have been evaluated once.
5496                 public static void EmitCall (EmitContext ec, bool is_base,
5497                                              bool is_static, Expression instance_expr,
5498                                              MethodBase method, ArrayList Arguments, Location loc,
5499                                              bool dup_args, bool omit_args)
5500                 {
5501                         ILGenerator ig = ec.ig;
5502                         bool struct_call = false;
5503                         bool this_call = false;
5504                         LocalTemporary this_arg = null;
5505
5506                         Type decl_type = method.DeclaringType;
5507
5508                         if (!RootContext.StdLib) {
5509                                 // Replace any calls to the system's System.Array type with calls to
5510                                 // the newly created one.
5511                                 if (method == TypeManager.system_int_array_get_length)
5512                                         method = TypeManager.int_array_get_length;
5513                                 else if (method == TypeManager.system_int_array_get_rank)
5514                                         method = TypeManager.int_array_get_rank;
5515                                 else if (method == TypeManager.system_object_array_clone)
5516                                         method = TypeManager.object_array_clone;
5517                                 else if (method == TypeManager.system_int_array_get_length_int)
5518                                         method = TypeManager.int_array_get_length_int;
5519                                 else if (method == TypeManager.system_int_array_get_lower_bound_int)
5520                                         method = TypeManager.int_array_get_lower_bound_int;
5521                                 else if (method == TypeManager.system_int_array_get_upper_bound_int)
5522                                         method = TypeManager.int_array_get_upper_bound_int;
5523                                 else if (method == TypeManager.system_void_array_copyto_array_int)
5524                                         method = TypeManager.void_array_copyto_array_int;
5525                         }
5526
5527                         if (ec.TestObsoleteMethodUsage) {
5528                                 //
5529                                 // This checks ObsoleteAttribute on the method and on the declaring type
5530                                 //
5531                                 ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (method);
5532                                 if (oa != null)
5533                                         AttributeTester.Report_ObsoleteMessage (oa, TypeManager.CSharpSignature (method), loc);
5534
5535                                 oa = AttributeTester.GetObsoleteAttribute (method.DeclaringType);
5536                                 if (oa != null) {
5537                                         AttributeTester.Report_ObsoleteMessage (oa, method.DeclaringType.FullName, loc);
5538                                 }
5539                         }
5540
5541                         if (IsMethodExcluded (method, ec))
5542                                 return;
5543
5544                         if (!is_static){
5545                                 this_call = instance_expr == null;
5546                                 if (decl_type.IsValueType || (!this_call && instance_expr.Type.IsValueType))
5547                                         struct_call = true;
5548
5549                                 //
5550                                 // If this is ourselves, push "this"
5551                                 //
5552                                 if (!omit_args) {
5553                                         Type t = null;
5554                                         if (this_call) {
5555                                                 ig.Emit (OpCodes.Ldarg_0);
5556                                                 t = decl_type;
5557                                         } else {
5558                                                 Type iexpr_type = instance_expr.Type;
5559
5560                                                 //
5561                                                 // Push the instance expression
5562                                                 //
5563                                                 if (TypeManager.IsValueType (iexpr_type)) {
5564                                                         //
5565                                                         // Special case: calls to a function declared in a
5566                                                         // reference-type with a value-type argument need
5567                                                         // to have their value boxed.
5568                                                         if (decl_type.IsValueType ||
5569                                                             iexpr_type.IsGenericParameter) {
5570                                                                 //
5571                                                                 // If the expression implements IMemoryLocation, then
5572                                                                 // we can optimize and use AddressOf on the
5573                                                                 // return.
5574                                                                 //
5575                                                                 // If not we have to use some temporary storage for
5576                                                                 // it.
5577                                                                 if (instance_expr is IMemoryLocation) {
5578                                                                         ((IMemoryLocation)instance_expr).
5579                                                                                 AddressOf (ec, AddressOp.LoadStore);
5580                                                                 } else {
5581                                                                         LocalTemporary temp = new LocalTemporary (ec, iexpr_type);
5582                                                                         instance_expr.Emit (ec);
5583                                                                         temp.Store (ec);
5584                                                                         temp.AddressOf (ec, AddressOp.Load);
5585                                                                 }
5586
5587                                                                 // avoid the overhead of doing this all the time.
5588                                                                 if (dup_args)
5589                                                                         t = TypeManager.GetReferenceType (iexpr_type);
5590                                                         } else {
5591                                                                 instance_expr.Emit (ec);
5592                                                                 ig.Emit (OpCodes.Box, instance_expr.Type);
5593                                                                 t = TypeManager.object_type;
5594                                                         }
5595                                                 } else {
5596                                                         instance_expr.Emit (ec);
5597                                                         t = instance_expr.Type;
5598                                                 }
5599                                         }
5600
5601                                         if (dup_args) {
5602                                                 this_arg = new LocalTemporary (ec, t);
5603                                                 ig.Emit (OpCodes.Dup);
5604                                                 this_arg.Store (ec);
5605                                         }
5606                                 }
5607                         }
5608
5609                         if (!omit_args)
5610                                 EmitArguments (ec, method, Arguments, dup_args, this_arg);
5611
5612                         if ((instance_expr != null) && (instance_expr.Type.IsGenericParameter))
5613                                 ig.Emit (OpCodes.Constrained, instance_expr.Type);
5614
5615                         OpCode call_op;
5616                         if (is_static || struct_call || is_base || (this_call && !method.IsVirtual))
5617                                 call_op = OpCodes.Call;
5618                         else
5619                                 call_op = OpCodes.Callvirt;
5620
5621                         if ((method.CallingConvention & CallingConventions.VarArgs) != 0) {
5622                                 Type[] varargs_types = GetVarargsTypes (ec, method, Arguments);
5623                                 ig.EmitCall (call_op, (MethodInfo) method, varargs_types);
5624                                 return;
5625                         }
5626
5627                         //
5628                         // If you have:
5629                         // this.DoFoo ();
5630                         // and DoFoo is not virtual, you can omit the callvirt,
5631                         // because you don't need the null checking behavior.
5632                         //
5633                         if (method is MethodInfo)
5634                                 ig.Emit (call_op, (MethodInfo) method);
5635                         else
5636                                 ig.Emit (call_op, (ConstructorInfo) method);
5637                 }
5638
5639                 public override void Emit (EmitContext ec)
5640                 {
5641                         MethodGroupExpr mg = (MethodGroupExpr) this.expr;
5642
5643                         EmitCall (ec, mg.IsBase, method.IsStatic, mg.InstanceExpression, method, Arguments, loc);
5644                 }
5645
5646                 public override void EmitStatement (EmitContext ec)
5647                 {
5648                         Emit (ec);
5649
5650                         //
5651                         // Pop the return value if there is one
5652                         //
5653                         if (method is MethodInfo){
5654                                 Type ret = ((MethodInfo)method).ReturnType;
5655                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
5656                                         ec.ig.Emit (OpCodes.Pop);
5657                         }
5658                 }
5659         }
5660
5661         public class InvocationOrCast : ExpressionStatement
5662         {
5663                 Expression expr;
5664                 Expression argument;
5665
5666                 public InvocationOrCast (Expression expr, Expression argument, Location loc)
5667                 {
5668                         this.expr = expr;
5669                         this.argument = argument;
5670                         this.loc = loc;
5671                 }
5672
5673                 public override Expression DoResolve (EmitContext ec)
5674                 {
5675                         //
5676                         // First try to resolve it as a cast.
5677                         //
5678                         TypeExpr te = expr.ResolveAsTypeStep (ec) as TypeExpr;
5679                         if ((te != null) && (te.eclass == ExprClass.Type)) {
5680                                 Cast cast = new Cast (te, argument, loc);
5681                                 return cast.Resolve (ec);
5682                         }
5683
5684                         //
5685                         // This can either be a type or a delegate invocation.
5686                         // Let's just resolve it and see what we'll get.
5687                         //
5688                         expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
5689                         if (expr == null)
5690                                 return null;
5691
5692                         //
5693                         // Ok, so it's a Cast.
5694                         //
5695                         if (expr.eclass == ExprClass.Type) {
5696                                 Cast cast = new Cast (new TypeExpression (expr.Type, loc), argument, loc);
5697                                 return cast.Resolve (ec);
5698                         }
5699
5700                         //
5701                         // It's a delegate invocation.
5702                         //
5703                         if (!TypeManager.IsDelegateType (expr.Type)) {
5704                                 Error (149, "Method name expected");
5705                                 return null;
5706                         }
5707
5708                         ArrayList args = new ArrayList ();
5709                         args.Add (new Argument (argument, Argument.AType.Expression));
5710                         DelegateInvocation invocation = new DelegateInvocation (expr, args, loc);
5711                         return invocation.Resolve (ec);
5712                 }
5713
5714                 void error201 ()
5715                 {
5716                         Error (201, "Only assignment, call, increment, decrement and new object " +
5717                                "expressions can be used as a statement");
5718                 }
5719
5720                 public override ExpressionStatement ResolveStatement (EmitContext ec)
5721                 {
5722                         //
5723                         // First try to resolve it as a cast.
5724                         //
5725                         TypeExpr te = expr.ResolveAsTypeStep (ec) as TypeExpr;
5726                         if ((te != null) && (te.eclass == ExprClass.Type)) {
5727                                 error201 ();
5728                                 return null;
5729                         }
5730
5731                         //
5732                         // This can either be a type or a delegate invocation.
5733                         // Let's just resolve it and see what we'll get.
5734                         //
5735                         expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
5736                         if ((expr == null) || (expr.eclass == ExprClass.Type)) {
5737                                 error201 ();
5738                                 return null;
5739                         }
5740
5741                         //
5742                         // It's a delegate invocation.
5743                         //
5744                         if (!TypeManager.IsDelegateType (expr.Type)) {
5745                                 Error (149, "Method name expected");
5746                                 return null;
5747                         }
5748
5749                         ArrayList args = new ArrayList ();
5750                         args.Add (new Argument (argument, Argument.AType.Expression));
5751                         DelegateInvocation invocation = new DelegateInvocation (expr, args, loc);
5752                         return invocation.ResolveStatement (ec);
5753                 }
5754
5755                 public override void Emit (EmitContext ec)
5756                 {
5757                         throw new Exception ("Cannot happen");
5758                 }
5759
5760                 public override void EmitStatement (EmitContext ec)
5761                 {
5762                         throw new Exception ("Cannot happen");
5763                 }
5764         }
5765
5766         //
5767         // This class is used to "disable" the code generation for the
5768         // temporary variable when initializing value types.
5769         //
5770         class EmptyAddressOf : EmptyExpression, IMemoryLocation {
5771                 public void AddressOf (EmitContext ec, AddressOp Mode)
5772                 {
5773                         // nothing
5774                 }
5775         }
5776
5777         /// <summary>
5778         ///    Implements the new expression
5779         /// </summary>
5780         public class New : ExpressionStatement, IMemoryLocation {
5781                 public readonly ArrayList Arguments;
5782
5783                 //
5784                 // During bootstrap, it contains the RequestedType,
5785                 // but if `type' is not null, it *might* contain a NewDelegate
5786                 // (because of field multi-initialization)
5787                 //
5788                 public Expression RequestedType;
5789
5790                 MethodBase method = null;
5791
5792                 //
5793                 // If set, the new expression is for a value_target, and
5794                 // we will not leave anything on the stack.
5795                 //
5796                 Expression value_target;
5797                 bool value_target_set = false;
5798                 bool is_type_parameter = false;
5799
5800                 public New (Expression requested_type, ArrayList arguments, Location l)
5801                 {
5802                         RequestedType = requested_type;
5803                         Arguments = arguments;
5804                         loc = l;
5805                 }
5806
5807                 public bool SetValueTypeVariable (Expression value)
5808                 {
5809                         value_target = value;
5810                         value_target_set = true;
5811                         if (!(value_target is IMemoryLocation)){
5812                                 Error_UnexpectedKind ("variable", loc);
5813                                 return false;
5814                         }
5815                         return true;
5816                 }
5817
5818                 //
5819                 // This function is used to disable the following code sequence for
5820                 // value type initialization:
5821                 //
5822                 // AddressOf (temporary)
5823                 // Construct/Init
5824                 // LoadTemporary
5825                 //
5826                 // Instead the provide will have provided us with the address on the
5827                 // stack to store the results.
5828                 //
5829                 static Expression MyEmptyExpression;
5830
5831                 public void DisableTemporaryValueType ()
5832                 {
5833                         if (MyEmptyExpression == null)
5834                                 MyEmptyExpression = new EmptyAddressOf ();
5835
5836                         //
5837                         // To enable this, look into:
5838                         // test-34 and test-89 and self bootstrapping.
5839                         //
5840                         // For instance, we can avoid a copy by using `newobj'
5841                         // instead of Call + Push-temp on value types.
5842 //                      value_target = MyEmptyExpression;
5843                 }
5844
5845
5846                 /// <summary>
5847                 /// Converts complex core type syntax like 'new int ()' to simple constant
5848                 /// </summary>
5849                 Expression Constantify (Type t)
5850                 {
5851                         if (t == TypeManager.int32_type)
5852                                 return new IntConstant (0);
5853                         if (t == TypeManager.uint32_type)
5854                                 return new UIntConstant (0);
5855                         if (t == TypeManager.int64_type)
5856                                 return new LongConstant (0);
5857                         if (t == TypeManager.uint64_type)
5858                                 return new ULongConstant (0);
5859                         if (t == TypeManager.float_type)
5860                                 return new FloatConstant (0);
5861                         if (t == TypeManager.double_type)
5862                                 return new DoubleConstant (0);
5863                         if (t == TypeManager.short_type)
5864                                 return new ShortConstant (0);
5865                         if (t == TypeManager.ushort_type)
5866                                 return new UShortConstant (0);
5867                         if (t == TypeManager.sbyte_type)
5868                                 return new SByteConstant (0);
5869                         if (t == TypeManager.byte_type)
5870                                 return new ByteConstant (0);
5871                         if (t == TypeManager.char_type)
5872                                 return new CharConstant ('\0');
5873                         if (t == TypeManager.bool_type)
5874                                 return new BoolConstant (false);
5875                         if (t == TypeManager.decimal_type)
5876                                 return new DecimalConstant (0);
5877
5878                         return null;
5879                 }
5880
5881                 public override Expression DoResolve (EmitContext ec)
5882                 {
5883                         //
5884                         // The New DoResolve might be called twice when initializing field
5885                         // expressions (see EmitFieldInitializers, the call to
5886                         // GetInitializerExpression will perform a resolve on the expression,
5887                         // and later the assign will trigger another resolution
5888                         //
5889                         // This leads to bugs (#37014)
5890                         //
5891                         if (type != null){
5892                                 if (RequestedType is NewDelegate)
5893                                         return RequestedType;
5894                                 return this;
5895                         }
5896
5897                         TypeExpr texpr = RequestedType.ResolveAsTypeTerminal (ec);
5898                         if (texpr == null)
5899                                 return null;
5900
5901                         if (Arguments == null) {
5902                                 Expression c = Constantify (type);
5903                                 if (c != null)
5904                                         return c;
5905                         }
5906
5907                         type = texpr.Type;
5908                         if (type == null)
5909                                 return null;
5910
5911                         CheckObsoleteAttribute (type);
5912
5913                         bool IsDelegate = TypeManager.IsDelegateType (type);
5914
5915                         if (IsDelegate){
5916                                 RequestedType = (new NewDelegate (type, Arguments, loc)).Resolve (ec);
5917                                 if (RequestedType != null)
5918                                         if (!(RequestedType is DelegateCreation))
5919                                                 throw new Exception ("NewDelegate.Resolve returned a non NewDelegate: " + RequestedType.GetType ());
5920                                 return RequestedType;
5921                         }
5922
5923                         if (type.IsGenericParameter) {
5924                                 if (!TypeManager.HasConstructorConstraint (type)) {
5925                                         Error (304, String.Format (
5926                                                        "Cannot create an instance of the " +
5927                                                        "variable type '{0}' because it " +
5928                                                        "doesn't have the new() constraint",
5929                                                        type));
5930                                         return null;
5931                                 }
5932
5933                                 if ((Arguments != null) && (Arguments.Count != 0)) {
5934                                         Error (417, String.Format (
5935                                                        "`{0}': cannot provide arguments " +
5936                                                        "when creating an instance of a " +
5937                                                        "variable type.", type));
5938                                         return null;
5939                                 }
5940
5941                                 is_type_parameter = true;
5942                                 eclass = ExprClass.Value;
5943                                 return this;
5944                         }
5945
5946                         if (type.IsInterface || type.IsAbstract){
5947                                 Error (144, "It is not possible to create instances of interfaces or abstract classes");
5948                                 return null;
5949                         }
5950
5951                         if (type.IsAbstract && type.IsSealed) {
5952                                 Report.Error (712, loc, "Cannot create an instance of the static class '{0}'", TypeManager.CSharpName (type));
5953                                 return null;
5954                         }
5955
5956                         bool is_struct = type.IsValueType;
5957                         eclass = ExprClass.Value;
5958
5959                         //
5960                         // SRE returns a match for .ctor () on structs (the object constructor),
5961                         // so we have to manually ignore it.
5962                         //
5963                         if (is_struct && Arguments == null)
5964                                 return this;
5965
5966                         Expression ml;
5967                         ml = MemberLookupFinal (ec, type, type, ".ctor",
5968                                                 // For member-lookup, treat 'new Foo (bar)' as call to 'foo.ctor (bar)', where 'foo' is of type 'Foo'.
5969                                                 MemberTypes.Constructor,
5970                                                 AllBindingFlags | BindingFlags.DeclaredOnly, loc);
5971
5972                         if (ml == null)
5973                                 return null;
5974
5975                         if (! (ml is MethodGroupExpr)){
5976                                 if (!is_struct){
5977                                         ml.Error_UnexpectedKind ("method group", loc);
5978                                         return null;
5979                                 }
5980                         }
5981
5982                         if (ml != null) {
5983                                 if (Arguments != null){
5984                                         foreach (Argument a in Arguments){
5985                                                 if (!a.Resolve (ec, loc))
5986                                                         return null;
5987                                         }
5988                                 }
5989
5990                                 method = Invocation.OverloadResolve (
5991                                         ec, (MethodGroupExpr) ml, Arguments, true, loc);
5992
5993                         }
5994
5995                         if (method == null) {
5996                                 if (almostMatchedMembers.Count != 0) {
5997                                         MemberLookupFailed (ec, type, type, ".ctor", null, loc);
5998                                         return null;
5999                                 }
6000
6001                                 if (!is_struct || Arguments.Count > 0) {
6002                                         Error (1501, String.Format (
6003                                             "New invocation: Can not find a constructor in `{0}' for this argument list",
6004                                             TypeManager.CSharpName (type)));
6005                                         return null;
6006                                 }
6007                         }
6008
6009                         return this;
6010                 }
6011
6012                 bool DoEmitTypeParameter (EmitContext ec)
6013                 {
6014                         ILGenerator ig = ec.ig;
6015
6016                         ig.Emit (OpCodes.Ldtoken, type);
6017                         ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
6018                         ig.Emit (OpCodes.Call, TypeManager.activator_create_instance);
6019                         ig.Emit (OpCodes.Unbox_Any, type);
6020
6021                         return true;
6022                 }
6023
6024                 //
6025                 // This DoEmit can be invoked in two contexts:
6026                 //    * As a mechanism that will leave a value on the stack (new object)
6027                 //    * As one that wont (init struct)
6028                 //
6029                 // You can control whether a value is required on the stack by passing
6030                 // need_value_on_stack.  The code *might* leave a value on the stack
6031                 // so it must be popped manually
6032                 //
6033                 // If we are dealing with a ValueType, we have a few
6034                 // situations to deal with:
6035                 //
6036                 //    * The target is a ValueType, and we have been provided
6037                 //      the instance (this is easy, we are being assigned).
6038                 //
6039                 //    * The target of New is being passed as an argument,
6040                 //      to a boxing operation or a function that takes a
6041                 //      ValueType.
6042                 //
6043                 //      In this case, we need to create a temporary variable
6044                 //      that is the argument of New.
6045                 //
6046                 // Returns whether a value is left on the stack
6047                 //
6048                 bool DoEmit (EmitContext ec, bool need_value_on_stack)
6049                 {
6050                         bool is_value_type = TypeManager.IsValueType (type);
6051                         ILGenerator ig = ec.ig;
6052
6053                         if (is_value_type){
6054                                 IMemoryLocation ml;
6055
6056                                 // Allow DoEmit() to be called multiple times.
6057                                 // We need to create a new LocalTemporary each time since
6058                                 // you can't share LocalBuilders among ILGeneators.
6059                                 if (!value_target_set)
6060                                         value_target = new LocalTemporary (ec, type);
6061
6062                                 ml = (IMemoryLocation) value_target;
6063                                 ml.AddressOf (ec, AddressOp.Store);
6064                         }
6065
6066                         if (method != null)
6067                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
6068
6069                         if (is_value_type){
6070                                 if (method == null)
6071                                         ig.Emit (OpCodes.Initobj, type);
6072                                 else
6073                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
6074                                 if (need_value_on_stack){
6075                                         value_target.Emit (ec);
6076                                         return true;
6077                                 }
6078                                 return false;
6079                         } else {
6080                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) method);
6081                                 return true;
6082                         }
6083                 }
6084
6085                 public override void Emit (EmitContext ec)
6086                 {
6087                         if (is_type_parameter)
6088                                 DoEmitTypeParameter (ec);
6089                         else
6090                                 DoEmit (ec, true);
6091                 }
6092
6093                 public override void EmitStatement (EmitContext ec)
6094                 {
6095                         if (is_type_parameter)
6096                                 throw new InvalidOperationException ();
6097
6098                         if (DoEmit (ec, false))
6099                                 ec.ig.Emit (OpCodes.Pop);
6100                 }
6101
6102                 public void AddressOf (EmitContext ec, AddressOp Mode)
6103                 {
6104                         if (is_type_parameter)
6105                                 throw new InvalidOperationException ();
6106
6107                         if (!type.IsValueType){
6108                                 //
6109                                 // We throw an exception.  So far, I believe we only need to support
6110                                 // value types:
6111                                 // foreach (int j in new StructType ())
6112                                 // see bug 42390
6113                                 //
6114                                 throw new Exception ("AddressOf should not be used for classes");
6115                         }
6116
6117                         if (!value_target_set)
6118                                 value_target = new LocalTemporary (ec, type);
6119
6120                         IMemoryLocation ml = (IMemoryLocation) value_target;
6121                         ml.AddressOf (ec, AddressOp.Store);
6122                         if (method != null)
6123                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
6124
6125                         if (method == null)
6126                                 ec.ig.Emit (OpCodes.Initobj, type);
6127                         else
6128                                 ec.ig.Emit (OpCodes.Call, (ConstructorInfo) method);
6129
6130                         ((IMemoryLocation) value_target).AddressOf (ec, Mode);
6131                 }
6132         }
6133
6134         /// <summary>
6135         ///   14.5.10.2: Represents an array creation expression.
6136         /// </summary>
6137         ///
6138         /// <remarks>
6139         ///   There are two possible scenarios here: one is an array creation
6140         ///   expression that specifies the dimensions and optionally the
6141         ///   initialization data and the other which does not need dimensions
6142         ///   specified but where initialization data is mandatory.
6143         /// </remarks>
6144         public class ArrayCreation : Expression {
6145                 Expression requested_base_type;
6146                 ArrayList initializers;
6147
6148                 //
6149                 // The list of Argument types.
6150                 // This is used to construct the `newarray' or constructor signature
6151                 //
6152                 ArrayList arguments;
6153
6154                 //
6155                 // Method used to create the array object.
6156                 //
6157                 MethodBase new_method = null;
6158
6159                 Type array_element_type;
6160                 Type underlying_type;
6161                 bool is_one_dimensional = false;
6162                 bool is_builtin_type = false;
6163                 bool expect_initializers = false;
6164                 int num_arguments = 0;
6165                 int dimensions = 0;
6166                 string rank;
6167
6168                 ArrayList array_data;
6169
6170                 Hashtable bounds;
6171
6172                 //
6173                 // The number of array initializers that we can handle
6174                 // via the InitializeArray method - through EmitStaticInitializers
6175                 //
6176                 int num_automatic_initializers;
6177
6178                 const int max_automatic_initializers = 6;
6179
6180                 public ArrayCreation (Expression requested_base_type, ArrayList exprs, string rank, ArrayList initializers, Location l)
6181                 {
6182                         this.requested_base_type = requested_base_type;
6183                         this.initializers = initializers;
6184                         this.rank = rank;
6185                         loc = l;
6186
6187                         arguments = new ArrayList ();
6188
6189                         foreach (Expression e in exprs) {
6190                                 arguments.Add (new Argument (e, Argument.AType.Expression));
6191                                 num_arguments++;
6192                         }
6193                 }
6194
6195                 public ArrayCreation (Expression requested_base_type, string rank, ArrayList initializers, Location l)
6196                 {
6197                         this.requested_base_type = requested_base_type;
6198                         this.initializers = initializers;
6199                         this.rank = rank;
6200                         loc = l;
6201
6202                         //this.rank = rank.Substring (0, rank.LastIndexOf ('['));
6203                         //
6204                         //string tmp = rank.Substring (rank.LastIndexOf ('['));
6205                         //
6206                         //dimensions = tmp.Length - 1;
6207                         expect_initializers = true;
6208                 }
6209
6210                 public Expression FormArrayType (Expression base_type, int idx_count, string rank)
6211                 {
6212                         StringBuilder sb = new StringBuilder (rank);
6213
6214                         sb.Append ("[");
6215                         for (int i = 1; i < idx_count; i++)
6216                                 sb.Append (",");
6217
6218                         sb.Append ("]");
6219
6220                         return new ComposedCast (base_type, sb.ToString (), loc);
6221                 }
6222
6223                 void Error_IncorrectArrayInitializer ()
6224                 {
6225                         Error (178, "Incorrectly structured array initializer");
6226                 }
6227
6228                 public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
6229                 {
6230                         if (specified_dims) {
6231                                 Argument a = (Argument) arguments [idx];
6232
6233                                 if (!a.Resolve (ec, loc))
6234                                         return false;
6235
6236                                 if (!(a.Expr is Constant)) {
6237                                         Error (150, "A constant value is expected");
6238                                         return false;
6239                                 }
6240
6241                                 int value = (int) ((Constant) a.Expr).GetValue ();
6242
6243                                 if (value != probe.Count) {
6244                                         Error_IncorrectArrayInitializer ();
6245                                         return false;
6246                                 }
6247
6248                                 bounds [idx] = value;
6249                         }
6250
6251                         int child_bounds = -1;
6252                         foreach (object o in probe) {
6253                                 if (o is ArrayList) {
6254                                         int current_bounds = ((ArrayList) o).Count;
6255
6256                                         if (child_bounds == -1)
6257                                                 child_bounds = current_bounds;
6258
6259                                         else if (child_bounds != current_bounds){
6260                                                 Error_IncorrectArrayInitializer ();
6261                                                 return false;
6262                                         }
6263                                         if (specified_dims && (idx + 1 >= arguments.Count)){
6264                                                 Error (623, "Array initializers can only be used in a variable or field initializer, try using the new expression");
6265                                                 return false;
6266                                         }
6267
6268                                         bool ret = CheckIndices (ec, (ArrayList) o, idx + 1, specified_dims);
6269                                         if (!ret)
6270                                                 return false;
6271                                 } else {
6272                                         if (child_bounds != -1){
6273                                                 Error_IncorrectArrayInitializer ();
6274                                                 return false;
6275                                         }
6276
6277                                         Expression tmp = (Expression) o;
6278                                         tmp = tmp.Resolve (ec);
6279                                         if (tmp == null)
6280                                                 return false;
6281
6282                                         // Console.WriteLine ("I got: " + tmp);
6283                                         // Handle initialization from vars, fields etc.
6284
6285                                         Expression conv = Convert.ImplicitConversionRequired (
6286                                                 ec, tmp, underlying_type, loc);
6287
6288                                         if (conv == null)
6289                                                 return false;
6290
6291                                         if (conv is StringConstant || conv is DecimalConstant || conv is NullCast) {
6292                                                 // These are subclasses of Constant that can appear as elements of an
6293                                                 // array that cannot be statically initialized (with num_automatic_initializers
6294                                                 // > max_automatic_initializers), so num_automatic_initializers should be left as zero.
6295                                                 array_data.Add (conv);
6296                                         } else if (conv is Constant) {
6297                                                 // These are the types of Constant that can appear in arrays that can be
6298                                                 // statically allocated.
6299                                                 array_data.Add (conv);
6300                                                 num_automatic_initializers++;
6301                                         } else
6302                                                 array_data.Add (conv);
6303                                 }
6304                         }
6305
6306                         return true;
6307                 }
6308
6309                 public void UpdateIndices (EmitContext ec)
6310                 {
6311                         int i = 0;
6312                         for (ArrayList probe = initializers; probe != null;) {
6313                                 if (probe.Count > 0 && probe [0] is ArrayList) {
6314                                         Expression e = new IntConstant (probe.Count);
6315                                         arguments.Add (new Argument (e, Argument.AType.Expression));
6316
6317                                         bounds [i++] =  probe.Count;
6318
6319                                         probe = (ArrayList) probe [0];
6320
6321                                 } else {
6322                                         Expression e = new IntConstant (probe.Count);
6323                                         arguments.Add (new Argument (e, Argument.AType.Expression));
6324
6325                                         bounds [i++] = probe.Count;
6326                                         probe = null;
6327                                 }
6328                         }
6329
6330                 }
6331
6332                 public bool ValidateInitializers (EmitContext ec, Type array_type)
6333                 {
6334                         if (initializers == null) {
6335                                 if (expect_initializers)
6336                                         return false;
6337                                 else
6338                                         return true;
6339                         }
6340
6341                         if (underlying_type == null)
6342                                 return false;
6343
6344                         //
6345                         // We use this to store all the date values in the order in which we
6346                         // will need to store them in the byte blob later
6347                         //
6348                         array_data = new ArrayList ();
6349                         bounds = new Hashtable ();
6350
6351                         bool ret;
6352
6353                         if (arguments != null) {
6354                                 ret = CheckIndices (ec, initializers, 0, true);
6355                                 return ret;
6356                         } else {
6357                                 arguments = new ArrayList ();
6358
6359                                 ret = CheckIndices (ec, initializers, 0, false);
6360
6361                                 if (!ret)
6362                                         return false;
6363
6364                                 UpdateIndices (ec);
6365
6366                                 if (arguments.Count != dimensions) {
6367                                         Error_IncorrectArrayInitializer ();
6368                                         return false;
6369                                 }
6370
6371                                 return ret;
6372                         }
6373                 }
6374
6375                 //
6376                 // Converts `source' to an int, uint, long or ulong.
6377                 //
6378                 Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
6379                 {
6380                         Expression target;
6381
6382                         bool old_checked = ec.CheckState;
6383                         ec.CheckState = true;
6384
6385                         target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
6386                         if (target == null){
6387                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
6388                                 if (target == null){
6389                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
6390                                         if (target == null){
6391                                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
6392                                                 if (target == null)
6393                                                         Convert.Error_CannotImplicitConversion (loc, source.Type, TypeManager.int32_type);
6394                                         }
6395                                 }
6396                         }
6397                         ec.CheckState = old_checked;
6398
6399                         //
6400                         // Only positive constants are allowed at compile time
6401                         //
6402                         if (target is Constant){
6403                                 if (target is IntConstant){
6404                                         if (((IntConstant) target).Value < 0){
6405                                                 Expression.Error_NegativeArrayIndex (loc);
6406                                                 return null;
6407                                         }
6408                                 }
6409
6410                                 if (target is LongConstant){
6411                                         if (((LongConstant) target).Value < 0){
6412                                                 Expression.Error_NegativeArrayIndex (loc);
6413                                                 return null;
6414                                         }
6415                                 }
6416
6417                         }
6418
6419                         return target;
6420                 }
6421
6422                 //
6423                 // Creates the type of the array
6424                 //
6425                 bool LookupType (EmitContext ec)
6426                 {
6427                         StringBuilder array_qualifier = new StringBuilder (rank);
6428
6429                         //
6430                         // `In the first form allocates an array instace of the type that results
6431                         // from deleting each of the individual expression from the expression list'
6432                         //
6433                         if (num_arguments > 0) {
6434                                 array_qualifier.Append ("[");
6435                                 for (int i = num_arguments-1; i > 0; i--)
6436                                         array_qualifier.Append (",");
6437                                 array_qualifier.Append ("]");
6438                         }
6439
6440                         //
6441                         // Lookup the type
6442                         //
6443                         TypeExpr array_type_expr;
6444                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
6445                         array_type_expr = array_type_expr.ResolveAsTypeTerminal (ec);
6446                         if (array_type_expr == null)
6447                                 return false;
6448
6449                         type = array_type_expr.Type;
6450
6451                         if (!type.IsArray) {
6452                                 Error (622, "Can only use array initializer expressions to assign to array types. Try using a new expression instead.");
6453                                 return false;
6454                         }
6455                         underlying_type = TypeManager.GetElementType (type);
6456                         dimensions = type.GetArrayRank ();
6457
6458                         return true;
6459                 }
6460
6461                 public override Expression DoResolve (EmitContext ec)
6462                 {
6463                         int arg_count;
6464
6465                         if (!LookupType (ec))
6466                                 return null;
6467
6468                         //
6469                         // First step is to validate the initializers and fill
6470                         // in any missing bits
6471                         //
6472                         if (!ValidateInitializers (ec, type))
6473                                 return null;
6474
6475                         if (arguments == null)
6476                                 arg_count = 0;
6477                         else {
6478                                 arg_count = arguments.Count;
6479                                 foreach (Argument a in arguments){
6480                                         if (!a.Resolve (ec, loc))
6481                                                 return null;
6482
6483                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
6484                                         if (real_arg == null)
6485                                                 return null;
6486
6487                                         a.Expr = real_arg;
6488                                 }
6489                         }
6490
6491                         array_element_type = TypeManager.GetElementType (type);
6492
6493                         if (array_element_type.IsAbstract && array_element_type.IsSealed) {
6494                                 Report.Error (719, loc, "'{0}': array elements cannot be of static type", TypeManager.CSharpName (array_element_type));
6495                                 return null;
6496                         }
6497
6498                         if (arg_count == 1) {
6499                                 is_one_dimensional = true;
6500                                 eclass = ExprClass.Value;
6501                                 return this;
6502                         }
6503
6504                         is_builtin_type = TypeManager.IsBuiltinType (type);
6505
6506                         if (is_builtin_type) {
6507                                 Expression ml;
6508
6509                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
6510                                                    AllBindingFlags, loc);
6511
6512                                 if (!(ml is MethodGroupExpr)) {
6513                                         ml.Error_UnexpectedKind ("method group", loc);
6514                                         return null;
6515                                 }
6516
6517                                 if (ml == null) {
6518                                         Error (-6, "New invocation: Can not find a constructor for " +
6519                                                       "this argument list");
6520                                         return null;
6521                                 }
6522
6523                                 new_method = Invocation.OverloadResolve (
6524                                         ec, (MethodGroupExpr) ml, arguments, false, loc);
6525
6526                                 if (new_method == null) {
6527                                         Error (-6, "New invocation: Can not find a constructor for " +
6528                                                       "this argument list");
6529                                         return null;
6530                                 }
6531
6532                                 eclass = ExprClass.Value;
6533                                 return this;
6534                         } else {
6535                                 ModuleBuilder mb = CodeGen.Module.Builder;
6536                                 ArrayList args = new ArrayList ();
6537
6538                                 if (arguments != null) {
6539                                         for (int i = 0; i < arg_count; i++)
6540                                                 args.Add (TypeManager.int32_type);
6541                                 }
6542
6543                                 Type [] arg_types = null;
6544
6545                                 if (args.Count > 0)
6546                                         arg_types = new Type [args.Count];
6547
6548                                 args.CopyTo (arg_types, 0);
6549
6550                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
6551                                                             arg_types);
6552
6553                                 if (new_method == null) {
6554                                         Error (-6, "New invocation: Can not find a constructor for " +
6555                                                       "this argument list");
6556                                         return null;
6557                                 }
6558
6559                                 eclass = ExprClass.Value;
6560                                 return this;
6561                         }
6562                 }
6563
6564                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
6565                 {
6566                         int factor;
6567                         byte [] data;
6568                         byte [] element;
6569                         int count = array_data.Count;
6570
6571                         if (underlying_type.IsEnum)
6572                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
6573
6574                         factor = GetTypeSize (underlying_type);
6575                         if (factor == 0)
6576                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
6577
6578                         data = new byte [(count * factor + 4) & ~3];
6579                         int idx = 0;
6580
6581                         for (int i = 0; i < count; ++i) {
6582                                 object v = array_data [i];
6583
6584                                 if (v is EnumConstant)
6585                                         v = ((EnumConstant) v).Child;
6586
6587                                 if (v is Constant && !(v is StringConstant))
6588                                         v = ((Constant) v).GetValue ();
6589                                 else {
6590                                         idx += factor;
6591                                         continue;
6592                                 }
6593
6594                                 if (underlying_type == TypeManager.int64_type){
6595                                         if (!(v is Expression)){
6596                                                 long val = (long) v;
6597
6598                                                 for (int j = 0; j < factor; ++j) {
6599                                                         data [idx + j] = (byte) (val & 0xFF);
6600                                                         val = (val >> 8);
6601                                                 }
6602                                         }
6603                                 } else if (underlying_type == TypeManager.uint64_type){
6604                                         if (!(v is Expression)){
6605                                                 ulong val = (ulong) v;
6606
6607                                                 for (int j = 0; j < factor; ++j) {
6608                                                         data [idx + j] = (byte) (val & 0xFF);
6609                                                         val = (val >> 8);
6610                                                 }
6611                                         }
6612                                 } else if (underlying_type == TypeManager.float_type) {
6613                                         if (!(v is Expression)){
6614                                                 element = BitConverter.GetBytes ((float) v);
6615
6616                                                 for (int j = 0; j < factor; ++j)
6617                                                         data [idx + j] = element [j];
6618                                         }
6619                                 } else if (underlying_type == TypeManager.double_type) {
6620                                         if (!(v is Expression)){
6621                                                 element = BitConverter.GetBytes ((double) v);
6622
6623                                                 for (int j = 0; j < factor; ++j)
6624                                                         data [idx + j] = element [j];
6625                                         }
6626                                 } else if (underlying_type == TypeManager.char_type){
6627                                         if (!(v is Expression)){
6628                                                 int val = (int) ((char) v);
6629
6630                                                 data [idx] = (byte) (val & 0xff);
6631                                                 data [idx+1] = (byte) (val >> 8);
6632                                         }
6633                                 } else if (underlying_type == TypeManager.short_type){
6634                                         if (!(v is Expression)){
6635                                                 int val = (int) ((short) v);
6636
6637                                                 data [idx] = (byte) (val & 0xff);
6638                                                 data [idx+1] = (byte) (val >> 8);
6639                                         }
6640                                 } else if (underlying_type == TypeManager.ushort_type){
6641                                         if (!(v is Expression)){
6642                                                 int val = (int) ((ushort) v);
6643
6644                                                 data [idx] = (byte) (val & 0xff);
6645                                                 data [idx+1] = (byte) (val >> 8);
6646                                         }
6647                                 } else if (underlying_type == TypeManager.int32_type) {
6648                                         if (!(v is Expression)){
6649                                                 int val = (int) v;
6650
6651                                                 data [idx]   = (byte) (val & 0xff);
6652                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6653                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6654                                                 data [idx+3] = (byte) (val >> 24);
6655                                         }
6656                                 } else if (underlying_type == TypeManager.uint32_type) {
6657                                         if (!(v is Expression)){
6658                                                 uint val = (uint) v;
6659
6660                                                 data [idx]   = (byte) (val & 0xff);
6661                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6662                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6663                                                 data [idx+3] = (byte) (val >> 24);
6664                                         }
6665                                 } else if (underlying_type == TypeManager.sbyte_type) {
6666                                         if (!(v is Expression)){
6667                                                 sbyte val = (sbyte) v;
6668                                                 data [idx] = (byte) val;
6669                                         }
6670                                 } else if (underlying_type == TypeManager.byte_type) {
6671                                         if (!(v is Expression)){
6672                                                 byte val = (byte) v;
6673                                                 data [idx] = (byte) val;
6674                                         }
6675                                 } else if (underlying_type == TypeManager.bool_type) {
6676                                         if (!(v is Expression)){
6677                                                 bool val = (bool) v;
6678                                                 data [idx] = (byte) (val ? 1 : 0);
6679                                         }
6680                                 } else if (underlying_type == TypeManager.decimal_type){
6681                                         if (!(v is Expression)){
6682                                                 int [] bits = Decimal.GetBits ((decimal) v);
6683                                                 int p = idx;
6684
6685                                                 // FIXME: For some reason, this doesn't work on the MS runtime.
6686                                                 int [] nbits = new int [4];
6687                                                 nbits [0] = bits [3];
6688                                                 nbits [1] = bits [2];
6689                                                 nbits [2] = bits [0];
6690                                                 nbits [3] = bits [1];
6691
6692                                                 for (int j = 0; j < 4; j++){
6693                                                         data [p++] = (byte) (nbits [j] & 0xff);
6694                                                         data [p++] = (byte) ((nbits [j] >> 8) & 0xff);
6695                                                         data [p++] = (byte) ((nbits [j] >> 16) & 0xff);
6696                                                         data [p++] = (byte) (nbits [j] >> 24);
6697                                                 }
6698                                         }
6699                                 } else
6700                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
6701
6702                                 idx += factor;
6703                         }
6704
6705                         return data;
6706                 }
6707
6708                 //
6709                 // Emits the initializers for the array
6710                 //
6711                 void EmitStaticInitializers (EmitContext ec)
6712                 {
6713                         //
6714                         // First, the static data
6715                         //
6716                         FieldBuilder fb;
6717                         ILGenerator ig = ec.ig;
6718
6719                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
6720
6721                         fb = RootContext.MakeStaticData (data);
6722
6723                         ig.Emit (OpCodes.Dup);
6724                         ig.Emit (OpCodes.Ldtoken, fb);
6725                         ig.Emit (OpCodes.Call,
6726                                  TypeManager.void_initializearray_array_fieldhandle);
6727                 }
6728
6729                 //
6730                 // Emits pieces of the array that can not be computed at compile
6731                 // time (variables and string locations).
6732                 //
6733                 // This always expect the top value on the stack to be the array
6734                 //
6735                 void EmitDynamicInitializers (EmitContext ec)
6736                 {
6737                         ILGenerator ig = ec.ig;
6738                         int dims = bounds.Count;
6739                         int [] current_pos = new int [dims];
6740                         int top = array_data.Count;
6741
6742                         MethodInfo set = null;
6743
6744                         if (dims != 1){
6745                                 Type [] args;
6746                                 ModuleBuilder mb = null;
6747                                 mb = CodeGen.Module.Builder;
6748                                 args = new Type [dims + 1];
6749
6750                                 int j;
6751                                 for (j = 0; j < dims; j++)
6752                                         args [j] = TypeManager.int32_type;
6753
6754                                 args [j] = array_element_type;
6755
6756                                 set = mb.GetArrayMethod (
6757                                         type, "Set",
6758                                         CallingConventions.HasThis | CallingConventions.Standard,
6759                                         TypeManager.void_type, args);
6760                         }
6761
6762                         for (int i = 0; i < top; i++){
6763
6764                                 Expression e = null;
6765
6766                                 if (array_data [i] is Expression)
6767                                         e = (Expression) array_data [i];
6768
6769                                 if (e != null) {
6770                                         //
6771                                         // Basically we do this for string literals and
6772                                         // other non-literal expressions
6773                                         //
6774                                         if (e is EnumConstant){
6775                                                 e = ((EnumConstant) e).Child;
6776                                         }
6777
6778                                         if (e is StringConstant || e is DecimalConstant || !(e is Constant) ||
6779                                             num_automatic_initializers <= max_automatic_initializers) {
6780                                                 Type etype = e.Type;
6781
6782                                                 ig.Emit (OpCodes.Dup);
6783
6784                                                 for (int idx = 0; idx < dims; idx++)
6785                                                         IntConstant.EmitInt (ig, current_pos [idx]);
6786
6787                                                 //
6788                                                 // If we are dealing with a struct, get the
6789                                                 // address of it, so we can store it.
6790                                                 //
6791                                                 if ((dims == 1) && etype.IsValueType &&
6792                                                     (!TypeManager.IsBuiltinOrEnum (etype) ||
6793                                                      etype == TypeManager.decimal_type)) {
6794                                                         if (e is New){
6795                                                                 New n = (New) e;
6796
6797                                                                 //
6798                                                                 // Let new know that we are providing
6799                                                                 // the address where to store the results
6800                                                                 //
6801                                                                 n.DisableTemporaryValueType ();
6802                                                         }
6803
6804                                                         ig.Emit (OpCodes.Ldelema, etype);
6805                                                 }
6806
6807                                                 e.Emit (ec);
6808
6809                                                 if (dims == 1) {
6810                                                         bool is_stobj, has_type_arg;
6811                                                         OpCode op = ArrayAccess.GetStoreOpcode (
6812                                                                 etype, out is_stobj,
6813                                                                 out has_type_arg);
6814                                                         if (is_stobj)
6815                                                                 ig.Emit (OpCodes.Stobj, etype);
6816                                                         else if (has_type_arg)
6817                                                                 ig.Emit (op, etype);
6818                                                         else
6819                                                                 ig.Emit (op);
6820                                                 } else
6821                                                         ig.Emit (OpCodes.Call, set);
6822                                         }
6823                                 }
6824
6825                                 //
6826                                 // Advance counter
6827                                 //
6828                                 for (int j = dims - 1; j >= 0; j--){
6829                                         current_pos [j]++;
6830                                         if (current_pos [j] < (int) bounds [j])
6831                                                 break;
6832                                         current_pos [j] = 0;
6833                                 }
6834                         }
6835                 }
6836
6837                 void EmitArrayArguments (EmitContext ec)
6838                 {
6839                         ILGenerator ig = ec.ig;
6840
6841                         foreach (Argument a in arguments) {
6842                                 Type atype = a.Type;
6843                                 a.Emit (ec);
6844
6845                                 if (atype == TypeManager.uint64_type)
6846                                         ig.Emit (OpCodes.Conv_Ovf_U4);
6847                                 else if (atype == TypeManager.int64_type)
6848                                         ig.Emit (OpCodes.Conv_Ovf_I4);
6849                         }
6850                 }
6851
6852                 public override void Emit (EmitContext ec)
6853                 {
6854                         ILGenerator ig = ec.ig;
6855
6856                         EmitArrayArguments (ec);
6857                         if (is_one_dimensional)
6858                                 ig.Emit (OpCodes.Newarr, array_element_type);
6859                         else {
6860                                 if (is_builtin_type)
6861                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
6862                                 else
6863                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
6864                         }
6865
6866                         if (initializers != null){
6867                                 //
6868                                 // FIXME: Set this variable correctly.
6869                                 //
6870                                 bool dynamic_initializers = true;
6871
6872                                 // This will never be true for array types that cannot be statically
6873                                 // initialized. num_automatic_initializers will always be zero.  See
6874                                 // CheckIndices.
6875                                         if (num_automatic_initializers > max_automatic_initializers)
6876                                                 EmitStaticInitializers (ec);
6877
6878                                 if (dynamic_initializers)
6879                                         EmitDynamicInitializers (ec);
6880                         }
6881                 }
6882
6883                 public object EncodeAsAttribute ()
6884                 {
6885                         if (!is_one_dimensional){
6886                                 Report.Error (-211, Location, "attribute can not encode multi-dimensional arrays");
6887                                 return null;
6888                         }
6889
6890                         if (array_data == null){
6891                                 Report.Error (-212, Location, "array should be initialized when passing it to an attribute");
6892                                 return null;
6893                         }
6894
6895                         object [] ret = new object [array_data.Count];
6896                         int i = 0;
6897                         foreach (Expression e in array_data){
6898                                 object v;
6899
6900                                 if (e is NullLiteral)
6901                                         v = null;
6902                                 else {
6903                                         if (!Attribute.GetAttributeArgumentExpression (e, Location, array_element_type, out v))
6904                                                 return null;
6905                                 }
6906                                 ret [i++] = v;
6907                         }
6908                         return ret;
6909                 }
6910         }
6911
6912         /// <summary>
6913         ///   Represents the `this' construct
6914         /// </summary>
6915         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
6916
6917                 Block block;
6918                 VariableInfo variable_info;
6919
6920                 public This (Block block, Location loc)
6921                 {
6922                         this.loc = loc;
6923                         this.block = block;
6924                 }
6925
6926                 public This (Location loc)
6927                 {
6928                         this.loc = loc;
6929                 }
6930
6931                 public VariableInfo VariableInfo {
6932                         get { return variable_info; }
6933                 }
6934
6935                 public bool VerifyFixed (bool is_expression)
6936                 {
6937                         if ((variable_info == null) || (variable_info.LocalInfo == null))
6938                                 return false;
6939                         else
6940                                 return variable_info.LocalInfo.IsFixed;
6941                 }
6942
6943                 public bool ResolveBase (EmitContext ec)
6944                 {
6945                         eclass = ExprClass.Variable;
6946
6947                         if (ec.TypeContainer.CurrentType != null)
6948                                 type = ec.TypeContainer.CurrentType;
6949                         else
6950                                 type = ec.ContainerType;
6951
6952                         if (ec.IsStatic) {
6953                                 Error (26, "Keyword this not valid in static code");
6954                                 return false;
6955                         }
6956
6957                         if ((block != null) && (block.ThisVariable != null))
6958                                 variable_info = block.ThisVariable.VariableInfo;
6959
6960                         if (ec.CurrentAnonymousMethod != null)
6961                                 ec.CaptureThis ();
6962
6963                         return true;
6964                 }
6965
6966                 public override Expression DoResolve (EmitContext ec)
6967                 {
6968                         if (!ResolveBase (ec))
6969                                 return null;
6970
6971                         if ((variable_info != null) && !variable_info.IsAssigned (ec)) {
6972                                 Error (188, "The this object cannot be used before all " +
6973                                        "of its fields are assigned to");
6974                                 variable_info.SetAssigned (ec);
6975                                 return this;
6976                         }
6977
6978                         if (ec.IsFieldInitializer) {
6979                                 Error (27, "Keyword `this' can't be used outside a constructor, " +
6980                                        "a method or a property.");
6981                                 return null;
6982                         }
6983
6984                         return this;
6985                 }
6986
6987                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
6988                 {
6989                         if (!ResolveBase (ec))
6990                                 return null;
6991
6992                         if (variable_info != null)
6993                                 variable_info.SetAssigned (ec);
6994
6995                         if (ec.TypeContainer is Class){
6996                                 Error (1604, "Cannot assign to `this'");
6997                                 return null;
6998                         }
6999
7000                         return this;
7001                 }
7002
7003                 public void Emit (EmitContext ec, bool leave_copy)
7004                 {
7005                         Emit (ec);
7006                         if (leave_copy)
7007                                 ec.ig.Emit (OpCodes.Dup);
7008                 }
7009
7010                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
7011                 {
7012                         ILGenerator ig = ec.ig;
7013
7014                         if (ec.TypeContainer is Struct){
7015                                 ec.EmitThis ();
7016                                 source.Emit (ec);
7017                                 if (leave_copy)
7018                                         ec.ig.Emit (OpCodes.Dup);
7019                                 ig.Emit (OpCodes.Stobj, type);
7020                         } else {
7021                                 throw new Exception ("how did you get here");
7022                         }
7023                 }
7024
7025                 public override void Emit (EmitContext ec)
7026                 {
7027                         ILGenerator ig = ec.ig;
7028
7029                         ec.EmitThis ();
7030                         if (ec.TypeContainer is Struct)
7031                                 ig.Emit (OpCodes.Ldobj, type);
7032                 }
7033
7034                 public void AddressOf (EmitContext ec, AddressOp mode)
7035                 {
7036                         ec.EmitThis ();
7037
7038                         // FIMXE
7039                         // FIGURE OUT WHY LDARG_S does not work
7040                         //
7041                         // consider: struct X { int val; int P { set { val = value; }}}
7042                         //
7043                         // Yes, this looks very bad. Look at `NOTAS' for
7044                         // an explanation.
7045                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
7046                 }
7047         }
7048
7049         /// <summary>
7050         ///   Represents the `__arglist' construct
7051         /// </summary>
7052         public class ArglistAccess : Expression
7053         {
7054                 public ArglistAccess (Location loc)
7055                 {
7056                         this.loc = loc;
7057                 }
7058
7059                 public bool ResolveBase (EmitContext ec)
7060                 {
7061                         eclass = ExprClass.Variable;
7062                         type = TypeManager.runtime_argument_handle_type;
7063                         return true;
7064                 }
7065
7066                 public override Expression DoResolve (EmitContext ec)
7067                 {
7068                         if (!ResolveBase (ec))
7069                                 return null;
7070
7071                         if (ec.IsFieldInitializer || !ec.CurrentBlock.HasVarargs) {
7072                                 Error (190, "The __arglist construct is valid only within " +
7073                                        "a variable argument method.");
7074                                 return null;
7075                         }
7076
7077                         return this;
7078                 }
7079
7080                 public override void Emit (EmitContext ec)
7081                 {
7082                         ec.ig.Emit (OpCodes.Arglist);
7083                 }
7084         }
7085
7086         /// <summary>
7087         ///   Represents the `__arglist (....)' construct
7088         /// </summary>
7089         public class Arglist : Expression
7090         {
7091                 public readonly Argument[] Arguments;
7092
7093                 public Arglist (Argument[] args, Location l)
7094                 {
7095                         Arguments = args;
7096                         loc = l;
7097                 }
7098
7099                 public Type[] ArgumentTypes {
7100                         get {
7101                                 Type[] retval = new Type [Arguments.Length];
7102                                 for (int i = 0; i < Arguments.Length; i++)
7103                                         retval [i] = Arguments [i].Type;
7104                                 return retval;
7105                         }
7106                 }
7107
7108                 public override Expression DoResolve (EmitContext ec)
7109                 {
7110                         eclass = ExprClass.Variable;
7111                         type = TypeManager.runtime_argument_handle_type;
7112
7113                         foreach (Argument arg in Arguments) {
7114                                 if (!arg.Resolve (ec, loc))
7115                                         return null;
7116                         }
7117
7118                         return this;
7119                 }
7120
7121                 public override void Emit (EmitContext ec)
7122                 {
7123                         foreach (Argument arg in Arguments)
7124                                 arg.Emit (ec);
7125                 }
7126         }
7127
7128         //
7129         // This produces the value that renders an instance, used by the iterators code
7130         //
7131         public class ProxyInstance : Expression, IMemoryLocation  {
7132                 public override Expression DoResolve (EmitContext ec)
7133                 {
7134                         eclass = ExprClass.Variable;
7135                         type = ec.ContainerType;
7136                         return this;
7137                 }
7138
7139                 public override void Emit (EmitContext ec)
7140                 {
7141                         ec.ig.Emit (OpCodes.Ldarg_0);
7142
7143                 }
7144
7145                 public void AddressOf (EmitContext ec, AddressOp mode)
7146                 {
7147                         ec.ig.Emit (OpCodes.Ldarg_0);
7148                 }
7149         }
7150
7151         /// <summary>
7152         ///   Implements the typeof operator
7153         /// </summary>
7154         public class TypeOf : Expression {
7155                 public Expression QueriedType;
7156                 protected Type typearg;
7157
7158                 public TypeOf (Expression queried_type, Location l)
7159                 {
7160                         QueriedType = queried_type;
7161                         loc = l;
7162                 }
7163
7164                 public override Expression DoResolve (EmitContext ec)
7165                 {
7166                         TypeExpr texpr = QueriedType.ResolveAsTypeTerminal (ec);
7167                         if (texpr == null)
7168                                 return null;
7169
7170                         typearg = texpr.Type;
7171
7172                         if (typearg == TypeManager.void_type) {
7173                                 Error (673, "System.Void cannot be used from C# - " +
7174                                        "use typeof (void) to get the void type object");
7175                                 return null;
7176                         }
7177
7178                         if (typearg.IsPointer && !ec.InUnsafe){
7179                                 UnsafeError (loc);
7180                                 return null;
7181                         }
7182                         CheckObsoleteAttribute (typearg);
7183
7184                         type = TypeManager.type_type;
7185                         eclass = ExprClass.Type;
7186                         return this;
7187                 }
7188
7189                 public override void Emit (EmitContext ec)
7190                 {
7191                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
7192                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
7193                 }
7194
7195                 public Type TypeArg {
7196                         get { return typearg; }
7197                 }
7198         }
7199
7200         /// <summary>
7201         ///   Implements the `typeof (void)' operator
7202         /// </summary>
7203         public class TypeOfVoid : TypeOf {
7204                 public TypeOfVoid (Location l) : base (null, l)
7205                 {
7206                         loc = l;
7207                 }
7208
7209                 public override Expression DoResolve (EmitContext ec)
7210                 {
7211                         type = TypeManager.type_type;
7212                         typearg = TypeManager.void_type;
7213                         eclass = ExprClass.Type;
7214                         return this;
7215                 }
7216         }
7217
7218         /// <summary>
7219         ///   Implements the sizeof expression
7220         /// </summary>
7221         public class SizeOf : Expression {
7222                 public Expression QueriedType;
7223                 Type type_queried;
7224
7225                 public SizeOf (Expression queried_type, Location l)
7226                 {
7227                         this.QueriedType = queried_type;
7228                         loc = l;
7229                 }
7230
7231                 public override Expression DoResolve (EmitContext ec)
7232                 {
7233                         if (!ec.InUnsafe) {
7234                                 Report.Error (
7235                                         233, loc, "Sizeof may only be used in an unsafe context " +
7236                                         "(consider using System.Runtime.InteropServices.Marshal.SizeOf");
7237                                 return null;
7238                         }
7239
7240                         TypeExpr texpr = QueriedType.ResolveAsTypeTerminal (ec);
7241                         if (texpr == null)
7242                                 return null;
7243
7244                         if (texpr is TypeParameterExpr){
7245                                 ((TypeParameterExpr)texpr).Error_CannotUseAsUnmanagedType (loc);
7246                                 return null;
7247                         }
7248
7249                         type_queried = texpr.Type;
7250
7251                         CheckObsoleteAttribute (type_queried);
7252
7253                         if (!TypeManager.IsUnmanagedType (type_queried)){
7254                                 Report.Error (208, loc, "Cannot take the size of an unmanaged type (" + TypeManager.CSharpName (type_queried) + ")");
7255                                 return null;
7256                         }
7257
7258                         type = TypeManager.int32_type;
7259                         eclass = ExprClass.Value;
7260                         return this;
7261                 }
7262
7263                 public override void Emit (EmitContext ec)
7264                 {
7265                         int size = GetTypeSize (type_queried);
7266
7267                         if (size == 0)
7268                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
7269                         else
7270                                 IntConstant.EmitInt (ec.ig, size);
7271                 }
7272         }
7273
7274         /// <summary>
7275         ///   Implements the member access expression
7276         /// </summary>
7277         public class MemberAccess : Expression {
7278                 public string Identifier;
7279                 protected Expression expr;
7280                 protected TypeArguments args;
7281
7282                 public MemberAccess (Expression expr, string id, Location l)
7283                 {
7284                         this.expr = expr;
7285                         Identifier = id;
7286                         loc = l;
7287                 }
7288
7289                 public MemberAccess (Expression expr, string id, TypeArguments args,
7290                                      Location l)
7291                         : this (expr, id, l)
7292                 {
7293                         this.args = args;
7294                 }
7295
7296                 public Expression Expr {
7297                         get {
7298                                 return expr;
7299                         }
7300                 }
7301
7302                 public static void error176 (Location loc, string name)
7303                 {
7304                         Report.Error (176, loc, "Static member `" +
7305                                       name + "' cannot be accessed " +
7306                                       "with an instance reference, qualify with a " +
7307                                       "type name instead");
7308                 }
7309
7310                 public static bool IdenticalNameAndTypeName (EmitContext ec, Expression left_original, Expression left, Location loc)
7311                 {
7312                         SimpleName sn = left_original as SimpleName;
7313                         if (sn == null || left == null || left.Type.Name != sn.Name)
7314                                 return false;
7315
7316                         return ec.DeclSpace.LookupType (sn.Name, true, loc) != null;
7317                 }
7318
7319                 // TODO: possible optimalization
7320                 // Cache resolved constant result in FieldBuilder <-> expresion map
7321                 public static Expression ResolveMemberAccess (EmitContext ec, Expression member_lookup,
7322                                                               Expression left, Location loc,
7323                                                               Expression left_original)
7324                 {
7325                         bool left_is_type, left_is_explicit;
7326
7327                         // If `left' is null, then we're called from SimpleNameResolve and this is
7328                         // a member in the currently defining class.
7329                         if (left == null) {
7330                                 left_is_type = ec.IsStatic || ec.IsFieldInitializer;
7331                                 left_is_explicit = false;
7332
7333                                 // Implicitly default to `this' unless we're static.
7334                                 if (!ec.IsStatic && !ec.IsFieldInitializer && !ec.InEnumContext)
7335                                         left = ec.GetThis (loc);
7336                         } else {
7337                                 left_is_type = left is TypeExpr;
7338                                 left_is_explicit = true;
7339                         }
7340
7341                         if (member_lookup is FieldExpr){
7342                                 FieldExpr fe = (FieldExpr) member_lookup;
7343                                 FieldInfo fi = fe.FieldInfo.Mono_GetGenericFieldDefinition ();
7344                                 Type decl_type = fi.DeclaringType;
7345
7346                                 bool is_emitted = fi is FieldBuilder;
7347                                 Type t = fi.FieldType;
7348
7349                                 if (is_emitted) {
7350                                         Const c = TypeManager.LookupConstant ((FieldBuilder) fi);
7351
7352                                         if (c != null) {
7353                                                 object o;
7354                                                 if (!c.LookupConstantValue (out o))
7355                                                         return null;
7356
7357                                                 object real_value = ((Constant) c.Expr).GetValue ();
7358
7359                                                 Expression exp = Constantify (real_value, t);
7360
7361                                                 if (left_is_explicit && !left_is_type && !IdenticalNameAndTypeName (ec, left_original, left, loc)) {
7362                                                         Report.SymbolRelatedToPreviousError (c);
7363                                                         error176 (loc, c.GetSignatureForError ());
7364                                                         return null;
7365                                                 }
7366
7367                                                 return exp;
7368                                         }
7369                                 }
7370
7371                                 // IsInitOnly is because of MS compatibility, I don't know why but they emit decimal constant as InitOnly
7372                                 if (fi.IsInitOnly && !is_emitted && t == TypeManager.decimal_type) {
7373                                         object[] attrs = fi.GetCustomAttributes (TypeManager.decimal_constant_attribute_type, false);
7374                                         if (attrs.Length == 1)
7375                                                 return new DecimalConstant (((System.Runtime.CompilerServices.DecimalConstantAttribute) attrs [0]).Value);
7376                                 }
7377
7378                                 if (fi.IsLiteral) {
7379                                         object o;
7380
7381                                         if (is_emitted)
7382                                                 o = TypeManager.GetValue ((FieldBuilder) fi);
7383                                         else
7384                                                 o = fi.GetValue (fi);
7385
7386                                         if (decl_type.IsSubclassOf (TypeManager.enum_type)) {
7387                                                 if (left_is_explicit && !left_is_type &&
7388                                                     !IdenticalNameAndTypeName (ec, left_original, member_lookup, loc)) {
7389                                                         error176 (loc, fe.FieldInfo.Name);
7390                                                         return null;
7391                                                 }
7392
7393                                                 Expression enum_member = MemberLookup (
7394                                                         ec, decl_type, "value__", MemberTypes.Field,
7395                                                         AllBindingFlags, loc);
7396
7397                                                 Enum en = TypeManager.LookupEnum (decl_type);
7398
7399                                                 Constant c;
7400                                                 if (en != null)
7401                                                         c = Constantify (o, en.UnderlyingType);
7402                                                 else
7403                                                         c = Constantify (o, enum_member.Type);
7404
7405                                                 return new EnumConstant (c, decl_type);
7406                                         }
7407
7408                                         Expression exp = Constantify (o, t);
7409
7410                                         if (left_is_explicit && !left_is_type) {
7411                                                 error176 (loc, fe.FieldInfo.Name);
7412                                                 return null;
7413                                         }
7414
7415                                         return exp;
7416                                 }
7417
7418                                 if (t.IsPointer && !ec.InUnsafe){
7419                                         UnsafeError (loc);
7420                                         return null;
7421                                 }
7422                         }
7423
7424                         if (member_lookup is EventExpr) {
7425                                 EventExpr ee = (EventExpr) member_lookup;
7426
7427                                 //
7428                                 // If the event is local to this class, we transform ourselves into
7429                                 // a FieldExpr
7430                                 //
7431
7432                                 if (ee.EventInfo.DeclaringType == ec.ContainerType ||
7433                                     TypeManager.IsNestedChildOf(ec.ContainerType, ee.EventInfo.DeclaringType)) {
7434                                         MemberInfo mi = GetFieldFromEvent (ee);
7435
7436                                         if (mi == null) {
7437                                                 //
7438                                                 // If this happens, then we have an event with its own
7439                                                 // accessors and private field etc so there's no need
7440                                                 // to transform ourselves.
7441                                                 //
7442                                                 ee.InstanceExpression = left;
7443                                                 return ee;
7444                                         }
7445
7446                                         Expression ml = ExprClassFromMemberInfo (ec, mi, loc);
7447
7448                                         if (ml == null) {
7449                                                 Report.Error (-200, loc, "Internal error!!");
7450                                                 return null;
7451                                         }
7452
7453                                         if (!left_is_explicit)
7454                                                 left = null;
7455
7456                                         ee.InstanceExpression = left;
7457
7458                                         return ResolveMemberAccess (ec, ml, left, loc, left_original);
7459                                 }
7460                         }
7461
7462                         if (member_lookup is IMemberExpr) {
7463                                 IMemberExpr me = (IMemberExpr) member_lookup;
7464                                 MethodGroupExpr mg = me as MethodGroupExpr;
7465
7466                                 if (left_is_type){
7467                                         if ((mg != null) && left_is_explicit && left.Type.IsInterface)
7468                                                 mg.IsExplicitImpl = left_is_explicit;
7469
7470                                         if (!me.IsStatic){
7471                                                 if ((ec.IsFieldInitializer || ec.IsStatic) &&
7472                                                     IdenticalNameAndTypeName (ec, left_original, member_lookup, loc))
7473                                                         return member_lookup;
7474
7475                                                 SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
7476                                                 return null;
7477                                         }
7478
7479                                 } else {
7480                                         if (!me.IsInstance){
7481                                                 if (IdenticalNameAndTypeName (ec, left_original, left, loc))
7482                                                         return member_lookup;
7483
7484                                                 if (left_is_explicit) {
7485                                                         error176 (loc, me.Name);
7486                                                         return null;
7487                                                 }
7488                                         }
7489
7490                                         //
7491                                         // Since we can not check for instance objects in SimpleName,
7492                                         // becaue of the rule that allows types and variables to share
7493                                         // the name (as long as they can be de-ambiguated later, see
7494                                         // IdenticalNameAndTypeName), we have to check whether left
7495                                         // is an instance variable in a static context
7496                                         //
7497                                         // However, if the left-hand value is explicitly given, then
7498                                         // it is already our instance expression, so we aren't in
7499                                         // static context.
7500                                         //
7501
7502                                         if (ec.IsStatic && !left_is_explicit && left is IMemberExpr){
7503                                                 IMemberExpr mexp = (IMemberExpr) left;
7504
7505                                                 if (!mexp.IsStatic){
7506                                                         SimpleName.Error_ObjectRefRequired (ec, loc, mexp.Name);
7507                                                         return null;
7508                                                 }
7509                                         }
7510
7511                                         if ((mg != null) && IdenticalNameAndTypeName (ec, left_original, left, loc))
7512                                                 mg.IdenticalTypeName = true;
7513
7514                                         me.InstanceExpression = left;
7515                                 }
7516
7517                                 return member_lookup;
7518                         }
7519
7520                         Console.WriteLine ("Left is: " + left);
7521                         Report.Error (-100, loc, "Support for [" + member_lookup + "] is not present yet");
7522                         Environment.Exit (1);
7523                         return null;
7524                 }
7525
7526                 public virtual Expression DoResolve (EmitContext ec, Expression right_side,
7527                                                      ResolveFlags flags)
7528                 {
7529                         if (type != null)
7530                                 throw new Exception ();
7531
7532                         //
7533                         // Resolve the expression with flow analysis turned off, we'll do the definite
7534                         // assignment checks later.  This is because we don't know yet what the expression
7535                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
7536                         // definite assignment check on the actual field and not on the whole struct.
7537                         //
7538
7539                         Expression original = expr;
7540                         expr = expr.Resolve (ec, flags | ResolveFlags.Intermediate | ResolveFlags.DisableFlowAnalysis);
7541                         if (expr == null)
7542                                 return null;
7543
7544                         if (expr is Namespace) {
7545                                 Namespace ns = (Namespace) expr;
7546                                 string lookup_id = MemberName.MakeName (Identifier, args);
7547                                 FullNamedExpression retval = ns.Lookup (ec.DeclSpace, lookup_id, loc);
7548                                 if ((retval != null) && (args != null))
7549                                         retval = new ConstructedType (retval, args, loc).ResolveAsTypeStep (ec);
7550                                 if (retval == null)
7551                                         Report.Error (234, loc, "The type or namespace name `{0}' could not be found in namespace `{1}'", Identifier, ns.FullName);
7552                                 return retval;
7553                         }
7554
7555                         //
7556                         // TODO: I mailed Ravi about this, and apparently we can get rid
7557                         // of this and put it in the right place.
7558                         //
7559                         // Handle enums here when they are in transit.
7560                         // Note that we cannot afford to hit MemberLookup in this case because
7561                         // it will fail to find any members at all
7562                         //
7563
7564                         Type expr_type;
7565                         if (expr is TypeExpr){
7566                                 expr_type = expr.Type;
7567
7568                                 if (!ec.DeclSpace.CheckAccessLevel (expr_type)){
7569                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", expr_type);
7570                                         return null;
7571                                 }
7572
7573                                 if (expr_type == TypeManager.enum_type || expr_type.IsSubclassOf (TypeManager.enum_type)){
7574                                         Enum en = TypeManager.LookupEnum (expr_type);
7575
7576                                         if (en != null) {
7577                                                 object value = en.LookupEnumValue (ec, Identifier, loc);
7578
7579                                                 if (value != null){
7580                                                         MemberCore mc = en.GetDefinition (Identifier);
7581                                                         ObsoleteAttribute oa = mc.GetObsoleteAttribute (en);
7582                                                         if (oa != null) {
7583                                                                 AttributeTester.Report_ObsoleteMessage (oa, mc.GetSignatureForError (), Location);
7584                                                         }
7585                                                         oa = en.GetObsoleteAttribute (en);
7586                                                         if (oa != null) {
7587                                                                 AttributeTester.Report_ObsoleteMessage (oa, en.GetSignatureForError (), Location);
7588                                                         }
7589
7590                                                         Constant c = Constantify (value, en.UnderlyingType);
7591                                                         return new EnumConstant (c, expr_type);
7592                                                 }
7593                                         } else {
7594                                                 CheckObsoleteAttribute (expr_type);
7595
7596                                                 FieldInfo fi = expr_type.GetField (Identifier);
7597                                                 if (fi != null) {
7598                                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (fi);
7599                                                         if (oa != null)
7600                                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (fi), Location);
7601                                                 }
7602                                         }
7603                                 }
7604                         } else
7605                                 expr_type = expr.Type;
7606
7607                         if (expr_type.IsPointer){
7608                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7609                                        TypeManager.CSharpName (expr_type) + ")");
7610                                 return null;
7611                         }
7612
7613                         Expression member_lookup;
7614                         member_lookup = MemberLookup (
7615                                 ec, expr_type, expr_type, Identifier, loc);
7616                         if ((member_lookup == null) && (args != null)) {
7617                                 string lookup_id = MemberName.MakeName (Identifier, args);
7618                                 member_lookup = MemberLookup (
7619                                         ec, expr_type, expr_type, lookup_id, loc);
7620                         }
7621                         if (member_lookup == null) {
7622                                 MemberLookupFailed (
7623                                         ec, expr_type, expr_type, Identifier, null, loc);
7624                                 return null;
7625                         }
7626
7627                         if (member_lookup is TypeExpr) {
7628                                 if (!(expr is TypeExpr) &&
7629                                     !IdenticalNameAndTypeName (ec, original, expr, loc)) {
7630                                         Error (572, "Can't reference type `" + Identifier + "' through an expression; try `" +
7631                                                member_lookup.Type + "' instead");
7632                                         return null;
7633                                 }
7634
7635                                 return member_lookup;
7636                         }
7637
7638                         if (args != null) {
7639                                 string full_name = expr_type + "." + Identifier;
7640
7641                                 if (member_lookup is FieldExpr) {
7642                                         Report.Error (307, loc, "The field `{0}' cannot " +
7643                                                       "be used with type arguments", full_name);
7644                                         return null;
7645                                 } else if (member_lookup is EventExpr) {
7646                                         Report.Error (307, loc, "The event `{0}' cannot " +
7647                                                       "be used with type arguments", full_name);
7648                                         return null;
7649                                 } else if (member_lookup is PropertyExpr) {
7650                                         Report.Error (307, loc, "The property `{0}' cannot " +
7651                                                       "be used with type arguments", full_name);
7652                                         return null;
7653                                 }
7654                         }
7655
7656                         member_lookup = ResolveMemberAccess (ec, member_lookup, expr, loc, original);
7657                         if (member_lookup == null)
7658                                 return null;
7659
7660                         if (args != null) {
7661                                 MethodGroupExpr mg = member_lookup as MethodGroupExpr;
7662                                 if (mg == null)
7663                                         throw new InternalErrorException ();
7664
7665                                 return mg.ResolveGeneric (ec, args);
7666                         }
7667
7668                         // The following DoResolve/DoResolveLValue will do the definite assignment
7669                         // check.
7670
7671                         if (right_side != null)
7672                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
7673                         else
7674                                 member_lookup = member_lookup.DoResolve (ec);
7675
7676                         return member_lookup;
7677                 }
7678
7679                 public override Expression DoResolve (EmitContext ec)
7680                 {
7681                         return DoResolve (ec, null, ResolveFlags.VariableOrValue | ResolveFlags.Type);
7682                 }
7683
7684                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7685                 {
7686                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue | ResolveFlags.Type);
7687                 }
7688
7689                 public override FullNamedExpression ResolveAsTypeStep (EmitContext ec)
7690                 {
7691                         return ResolveNamespaceOrType (ec, false);
7692                 }
7693
7694                 public FullNamedExpression ResolveNamespaceOrType (EmitContext ec, bool silent)
7695                 {
7696                         FullNamedExpression new_expr = expr.ResolveAsTypeStep (ec);
7697
7698                         if (new_expr == null)
7699                                 return null;
7700
7701                         string lookup_id = MemberName.MakeName (Identifier, args);
7702
7703                         if (new_expr is Namespace) {
7704                                 Namespace ns = (Namespace) new_expr;
7705                                 FullNamedExpression retval = ns.Lookup (ec.DeclSpace, lookup_id, loc);
7706                                 if ((retval != null) && (args != null))
7707                                         retval = new ConstructedType (retval, args, loc).ResolveAsTypeStep (ec);
7708                                 if (!silent && retval == null)
7709                                         Report.Error (234, loc, "The type or namespace name `{0}' could not be found in namespace `{1}'", Identifier, ns.FullName);
7710                                 return retval;
7711                         }
7712
7713                         TypeExpr tnew_expr = new_expr.ResolveAsTypeTerminal (ec);
7714                         if (tnew_expr == null)
7715                                 return null;
7716
7717                         Type expr_type = tnew_expr.Type;
7718
7719                         if (expr_type.IsPointer){
7720                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7721                                        TypeManager.CSharpName (expr_type) + ")");
7722                                 return null;
7723                         }
7724
7725                         Expression member_lookup;
7726                         member_lookup = MemberLookupFinal (ec, expr_type, expr_type, lookup_id, loc);
7727                         if (!silent && member_lookup == null) {
7728                                 Report.Error (234, loc, "The type name `{0}' could not be found in type `{1}'",
7729                                               Identifier, new_expr.FullName);
7730                                 return null;
7731                         }
7732
7733                         if (!(member_lookup is TypeExpr)) {
7734                                 Report.Error (118, loc, "'{0}.{1}' denotes a '{2}', where a type was expected",
7735                                               new_expr.FullName, Identifier, member_lookup.ExprClassName ());
7736                                 return null;
7737                         }
7738
7739                         TypeExpr texpr = member_lookup.ResolveAsTypeTerminal (ec);
7740                         if (texpr == null)
7741                                 return null;
7742
7743                         TypeArguments the_args = args;
7744                         if (TypeManager.HasGenericArguments (expr_type)) {
7745                                 Type[] decl_args = TypeManager.GetTypeArguments (expr_type);
7746
7747                                 TypeArguments new_args = new TypeArguments (loc);
7748                                 foreach (Type decl in decl_args)
7749                                         new_args.Add (new TypeExpression (decl, loc));
7750
7751                                 if (args != null)
7752                                         new_args.Add (args);
7753
7754                                 the_args = new_args;
7755                         }
7756
7757                         if (the_args != null) {
7758                                 ConstructedType ctype = new ConstructedType (texpr.Type, the_args, loc);
7759                                 return ctype.ResolveAsTypeStep (ec);
7760                         }
7761
7762                         return texpr;
7763                 }
7764
7765                 public override void Emit (EmitContext ec)
7766                 {
7767                         throw new Exception ("Should not happen");
7768                 }
7769
7770                 public override string ToString ()
7771                 {
7772                         return expr + "." + MemberName.MakeName (Identifier, args);
7773                 }
7774         }
7775
7776         /// <summary>
7777         ///   Implements checked expressions
7778         /// </summary>
7779         public class CheckedExpr : Expression {
7780
7781                 public Expression Expr;
7782
7783                 public CheckedExpr (Expression e, Location l)
7784                 {
7785                         Expr = e;
7786                         loc = l;
7787                 }
7788
7789                 public override Expression DoResolve (EmitContext ec)
7790                 {
7791                         bool last_check = ec.CheckState;
7792                         bool last_const_check = ec.ConstantCheckState;
7793
7794                         ec.CheckState = true;
7795                         ec.ConstantCheckState = true;
7796                         Expr = Expr.Resolve (ec);
7797                         ec.CheckState = last_check;
7798                         ec.ConstantCheckState = last_const_check;
7799
7800                         if (Expr == null)
7801                                 return null;
7802
7803                         if (Expr is Constant)
7804                                 return Expr;
7805
7806                         eclass = Expr.eclass;
7807                         type = Expr.Type;
7808                         return this;
7809                 }
7810
7811                 public override void Emit (EmitContext ec)
7812                 {
7813                         bool last_check = ec.CheckState;
7814                         bool last_const_check = ec.ConstantCheckState;
7815
7816                         ec.CheckState = true;
7817                         ec.ConstantCheckState = true;
7818                         Expr.Emit (ec);
7819                         ec.CheckState = last_check;
7820                         ec.ConstantCheckState = last_const_check;
7821                 }
7822
7823         }
7824
7825         /// <summary>
7826         ///   Implements the unchecked expression
7827         /// </summary>
7828         public class UnCheckedExpr : Expression {
7829
7830                 public Expression Expr;
7831
7832                 public UnCheckedExpr (Expression e, Location l)
7833                 {
7834                         Expr = e;
7835                         loc = l;
7836                 }
7837
7838                 public override Expression DoResolve (EmitContext ec)
7839                 {
7840                         bool last_check = ec.CheckState;
7841                         bool last_const_check = ec.ConstantCheckState;
7842
7843                         ec.CheckState = false;
7844                         ec.ConstantCheckState = false;
7845                         Expr = Expr.Resolve (ec);
7846                         ec.CheckState = last_check;
7847                         ec.ConstantCheckState = last_const_check;
7848
7849                         if (Expr == null)
7850                                 return null;
7851
7852                         if (Expr is Constant)
7853                                 return Expr;
7854
7855                         eclass = Expr.eclass;
7856                         type = Expr.Type;
7857                         return this;
7858                 }
7859
7860                 public override void Emit (EmitContext ec)
7861                 {
7862                         bool last_check = ec.CheckState;
7863                         bool last_const_check = ec.ConstantCheckState;
7864
7865                         ec.CheckState = false;
7866                         ec.ConstantCheckState = false;
7867                         Expr.Emit (ec);
7868                         ec.CheckState = last_check;
7869                         ec.ConstantCheckState = last_const_check;
7870                 }
7871
7872         }
7873
7874         /// <summary>
7875         ///   An Element Access expression.
7876         ///
7877         ///   During semantic analysis these are transformed into
7878         ///   IndexerAccess, ArrayAccess or a PointerArithmetic.
7879         /// </summary>
7880         public class ElementAccess : Expression {
7881                 public ArrayList  Arguments;
7882                 public Expression Expr;
7883
7884                 public ElementAccess (Expression e, ArrayList e_list, Location l)
7885                 {
7886                         Expr = e;
7887
7888                         loc  = l;
7889
7890                         if (e_list == null)
7891                                 return;
7892
7893                         Arguments = new ArrayList ();
7894                         foreach (Expression tmp in e_list)
7895                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
7896
7897                 }
7898
7899                 bool CommonResolve (EmitContext ec)
7900                 {
7901                         Expr = Expr.Resolve (ec);
7902
7903                         if (Expr == null)
7904                                 return false;
7905
7906                         if (Arguments == null)
7907                                 return false;
7908
7909                         foreach (Argument a in Arguments){
7910                                 if (!a.Resolve (ec, loc))
7911                                         return false;
7912                         }
7913
7914                         return true;
7915                 }
7916
7917                 Expression MakePointerAccess (EmitContext ec, Type t)
7918                 {
7919                         if (t == TypeManager.void_ptr_type){
7920                                 Error (242, "The array index operation is not valid for void pointers");
7921                                 return null;
7922                         }
7923                         if (Arguments.Count != 1){
7924                                 Error (196, "A pointer must be indexed by a single value");
7925                                 return null;
7926                         }
7927                         Expression p;
7928
7929                         p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr, t, loc).Resolve (ec);
7930                         if (p == null)
7931                                 return null;
7932                         return new Indirection (p, loc).Resolve (ec);
7933                 }
7934
7935                 public override Expression DoResolve (EmitContext ec)
7936                 {
7937                         if (!CommonResolve (ec))
7938                                 return null;
7939
7940                         //
7941                         // We perform some simple tests, and then to "split" the emit and store
7942                         // code we create an instance of a different class, and return that.
7943                         //
7944                         // I am experimenting with this pattern.
7945                         //
7946                         Type t = Expr.Type;
7947
7948                         if (t == TypeManager.array_type){
7949                                 Report.Error (21, loc, "Cannot use indexer on System.Array");
7950                                 return null;
7951                         }
7952
7953                         if (t.IsArray)
7954                                 return (new ArrayAccess (this, loc)).Resolve (ec);
7955                         if (t.IsPointer)
7956                                 return MakePointerAccess (ec, Expr.Type);
7957
7958                         FieldExpr fe = Expr as FieldExpr;
7959                         if (fe != null) {
7960                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (fe.FieldInfo);
7961                                 if (ff != null) {
7962                                         return MakePointerAccess (ec, ff.ElementType);
7963                                 }
7964                         }
7965                         return (new IndexerAccess (this, loc)).Resolve (ec);
7966                 }
7967
7968                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7969                 {
7970                         if (!CommonResolve (ec))
7971                                 return null;
7972
7973                         Type t = Expr.Type;
7974                         if (t.IsArray)
7975                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
7976
7977                         if (t.IsPointer)
7978                                 return MakePointerAccess (ec, Expr.Type);
7979
7980                         FieldExpr fe = Expr as FieldExpr;
7981                         if (fe != null) {
7982                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (fe.FieldInfo);
7983                                 if (ff != null) {
7984 // TODO: not sure whether it is correct
7985 //                                      if (!ec.InFixedInitializer) {
7986 //                                      if (!ec.InFixedInitializer) {
7987 //                                              Error (1666, "You cannot use fixed sized buffers contained in unfixed expressions. Try using the fixed statement.");
7988 //                                              return null;
7989 //                                      }
7990                                         return MakePointerAccess (ec, ff.ElementType);
7991                                 }
7992                         }
7993                         return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
7994                 }
7995
7996                 public override void Emit (EmitContext ec)
7997                 {
7998                         throw new Exception ("Should never be reached");
7999                 }
8000         }
8001
8002         /// <summary>
8003         ///   Implements array access
8004         /// </summary>
8005         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
8006                 //
8007                 // Points to our "data" repository
8008                 //
8009                 ElementAccess ea;
8010
8011                 LocalTemporary temp;
8012                 bool prepared;
8013
8014                 public ArrayAccess (ElementAccess ea_data, Location l)
8015                 {
8016                         ea = ea_data;
8017                         eclass = ExprClass.Variable;
8018                         loc = l;
8019                 }
8020
8021                 public override Expression DoResolve (EmitContext ec)
8022                 {
8023 #if false
8024                         ExprClass eclass = ea.Expr.eclass;
8025
8026                         // As long as the type is valid
8027                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
8028                               eclass == ExprClass.Value)) {
8029                                 ea.Expr.Error_UnexpectedKind ("variable or value");
8030                                 return null;
8031                         }
8032 #endif
8033
8034                         Type t = ea.Expr.Type;
8035                         if (t.GetArrayRank () != ea.Arguments.Count){
8036                                 ea.Error (22,
8037                                           "Incorrect number of indexes for array " +
8038                                           " expected: " + t.GetArrayRank () + " got: " +
8039                                           ea.Arguments.Count);
8040                                 return null;
8041                         }
8042
8043                         type = TypeManager.GetElementType (t);
8044                         if (type.IsPointer && !ec.InUnsafe){
8045                                 UnsafeError (ea.Location);
8046                                 return null;
8047                         }
8048
8049                         foreach (Argument a in ea.Arguments){
8050                                 Type argtype = a.Type;
8051
8052                                 if (argtype == TypeManager.int32_type ||
8053                                     argtype == TypeManager.uint32_type ||
8054                                     argtype == TypeManager.int64_type ||
8055                                     argtype == TypeManager.uint64_type) {
8056                                         Constant c = a.Expr as Constant;
8057                                         if (c != null && c.IsNegative) {
8058                                                 Report.Warning (251, 2, a.Expr.Location, "Indexing an array with a negative index (array indices always start at zero)");
8059                                         }
8060                                         continue;
8061                                 }
8062
8063                                 //
8064                                 // Mhm.  This is strage, because the Argument.Type is not the same as
8065                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
8066                                 //
8067                                 // Wonder if I will run into trouble for this.
8068                                 //
8069                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
8070                                 if (a.Expr == null)
8071                                         return null;
8072                         }
8073
8074                         eclass = ExprClass.Variable;
8075
8076                         return this;
8077                 }
8078
8079                 /// <summary>
8080                 ///    Emits the right opcode to load an object of Type `t'
8081                 ///    from an array of T
8082                 /// </summary>
8083                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
8084                 {
8085                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
8086                                 ig.Emit (OpCodes.Ldelem_U1);
8087                         else if (type == TypeManager.sbyte_type)
8088                                 ig.Emit (OpCodes.Ldelem_I1);
8089                         else if (type == TypeManager.short_type)
8090                                 ig.Emit (OpCodes.Ldelem_I2);
8091                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
8092                                 ig.Emit (OpCodes.Ldelem_U2);
8093                         else if (type == TypeManager.int32_type)
8094                                 ig.Emit (OpCodes.Ldelem_I4);
8095                         else if (type == TypeManager.uint32_type)
8096                                 ig.Emit (OpCodes.Ldelem_U4);
8097                         else if (type == TypeManager.uint64_type)
8098                                 ig.Emit (OpCodes.Ldelem_I8);
8099                         else if (type == TypeManager.int64_type)
8100                                 ig.Emit (OpCodes.Ldelem_I8);
8101                         else if (type == TypeManager.float_type)
8102                                 ig.Emit (OpCodes.Ldelem_R4);
8103                         else if (type == TypeManager.double_type)
8104                                 ig.Emit (OpCodes.Ldelem_R8);
8105                         else if (type == TypeManager.intptr_type)
8106                                 ig.Emit (OpCodes.Ldelem_I);
8107                         else if (TypeManager.IsEnumType (type)){
8108                                 EmitLoadOpcode (ig, TypeManager.EnumToUnderlying (type));
8109                         } else if (type.IsValueType){
8110                                 ig.Emit (OpCodes.Ldelema, type);
8111                                 ig.Emit (OpCodes.Ldobj, type);
8112                         } else if (type.IsGenericParameter)
8113                                 ig.Emit (OpCodes.Ldelem_Any, type);
8114                         else
8115                                 ig.Emit (OpCodes.Ldelem_Ref);
8116                 }
8117
8118                 /// <summary>
8119                 ///    Returns the right opcode to store an object of Type `t'
8120                 ///    from an array of T.
8121                 /// </summary>
8122                 static public OpCode GetStoreOpcode (Type t, out bool is_stobj, out bool has_type_arg)
8123                 {
8124                         //Console.WriteLine (new System.Diagnostics.StackTrace ());
8125                         has_type_arg = false; is_stobj = false;
8126                         t = TypeManager.TypeToCoreType (t);
8127                         if (TypeManager.IsEnumType (t))
8128                                 t = TypeManager.EnumToUnderlying (t);
8129                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
8130                             t == TypeManager.bool_type)
8131                                 return OpCodes.Stelem_I1;
8132                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type ||
8133                                  t == TypeManager.char_type)
8134                                 return OpCodes.Stelem_I2;
8135                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
8136                                 return OpCodes.Stelem_I4;
8137                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
8138                                 return OpCodes.Stelem_I8;
8139                         else if (t == TypeManager.float_type)
8140                                 return OpCodes.Stelem_R4;
8141                         else if (t == TypeManager.double_type)
8142                                 return OpCodes.Stelem_R8;
8143                         else if (t == TypeManager.intptr_type) {
8144                                 has_type_arg = true;
8145                                 is_stobj = true;
8146                                 return OpCodes.Stobj;
8147                         } else if (t.IsValueType) {
8148                                 has_type_arg = true;
8149                                 is_stobj = true;
8150                                 return OpCodes.Stobj;
8151                         } else if (t.IsGenericParameter) {
8152                                 has_type_arg = true;
8153                                 return OpCodes.Stelem_Any;
8154                         } else
8155                                 return OpCodes.Stelem_Ref;
8156                 }
8157
8158                 MethodInfo FetchGetMethod ()
8159                 {
8160                         ModuleBuilder mb = CodeGen.Module.Builder;
8161                         int arg_count = ea.Arguments.Count;
8162                         Type [] args = new Type [arg_count];
8163                         MethodInfo get;
8164
8165                         for (int i = 0; i < arg_count; i++){
8166                                 //args [i++] = a.Type;
8167                                 args [i] = TypeManager.int32_type;
8168                         }
8169
8170                         get = mb.GetArrayMethod (
8171                                 ea.Expr.Type, "Get",
8172                                 CallingConventions.HasThis |
8173                                 CallingConventions.Standard,
8174                                 type, args);
8175                         return get;
8176                 }
8177
8178
8179                 MethodInfo FetchAddressMethod ()
8180                 {
8181                         ModuleBuilder mb = CodeGen.Module.Builder;
8182                         int arg_count = ea.Arguments.Count;
8183                         Type [] args = new Type [arg_count];
8184                         MethodInfo address;
8185                         Type ret_type;
8186
8187                         ret_type = TypeManager.GetReferenceType (type);
8188
8189                         for (int i = 0; i < arg_count; i++){
8190                                 //args [i++] = a.Type;
8191                                 args [i] = TypeManager.int32_type;
8192                         }
8193
8194                         address = mb.GetArrayMethod (
8195                                 ea.Expr.Type, "Address",
8196                                 CallingConventions.HasThis |
8197                                 CallingConventions.Standard,
8198                                 ret_type, args);
8199
8200                         return address;
8201                 }
8202
8203                 //
8204                 // Load the array arguments into the stack.
8205                 //
8206                 // If we have been requested to cache the values (cached_locations array
8207                 // initialized), then load the arguments the first time and store them
8208                 // in locals.  otherwise load from local variables.
8209                 //
8210                 void LoadArrayAndArguments (EmitContext ec)
8211                 {
8212                         ILGenerator ig = ec.ig;
8213
8214                         ea.Expr.Emit (ec);
8215                         foreach (Argument a in ea.Arguments){
8216                                 Type argtype = a.Expr.Type;
8217
8218                                 a.Expr.Emit (ec);
8219
8220                                 if (argtype == TypeManager.int64_type)
8221                                         ig.Emit (OpCodes.Conv_Ovf_I);
8222                                 else if (argtype == TypeManager.uint64_type)
8223                                         ig.Emit (OpCodes.Conv_Ovf_I_Un);
8224                         }
8225                 }
8226
8227                 public void Emit (EmitContext ec, bool leave_copy)
8228                 {
8229                         int rank = ea.Expr.Type.GetArrayRank ();
8230                         ILGenerator ig = ec.ig;
8231
8232                         if (!prepared) {
8233                                 LoadArrayAndArguments (ec);
8234
8235                                 if (rank == 1)
8236                                         EmitLoadOpcode (ig, type);
8237                                 else {
8238                                         MethodInfo method;
8239
8240                                         method = FetchGetMethod ();
8241                                         ig.Emit (OpCodes.Call, method);
8242                                 }
8243                         } else
8244                                 LoadFromPtr (ec.ig, this.type);
8245
8246                         if (leave_copy) {
8247                                 ec.ig.Emit (OpCodes.Dup);
8248                                 temp = new LocalTemporary (ec, this.type);
8249                                 temp.Store (ec);
8250                         }
8251                 }
8252
8253                 public override void Emit (EmitContext ec)
8254                 {
8255                         Emit (ec, false);
8256                 }
8257
8258                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8259                 {
8260                         int rank = ea.Expr.Type.GetArrayRank ();
8261                         ILGenerator ig = ec.ig;
8262                         Type t = source.Type;
8263                         prepared = prepare_for_load;
8264
8265                         if (prepare_for_load) {
8266                                 AddressOf (ec, AddressOp.LoadStore);
8267                                 ec.ig.Emit (OpCodes.Dup);
8268                                 source.Emit (ec);
8269                                 if (leave_copy) {
8270                                         ec.ig.Emit (OpCodes.Dup);
8271                                         temp = new LocalTemporary (ec, this.type);
8272                                         temp.Store (ec);
8273                                 }
8274                                 StoreFromPtr (ec.ig, t);
8275
8276                                 if (temp != null)
8277                                         temp.Emit (ec);
8278
8279                                 return;
8280                         }
8281
8282                         LoadArrayAndArguments (ec);
8283
8284                         if (rank == 1) {
8285                                 bool is_stobj, has_type_arg;
8286                                 OpCode op = GetStoreOpcode (t, out is_stobj, out has_type_arg);
8287
8288                                 //
8289                                 // The stobj opcode used by value types will need
8290                                 // an address on the stack, not really an array/array
8291                                 // pair
8292                                 //
8293                                 if (is_stobj)
8294                                         ig.Emit (OpCodes.Ldelema, t);
8295
8296                                 source.Emit (ec);
8297                                 if (leave_copy) {
8298                                         ec.ig.Emit (OpCodes.Dup);
8299                                         temp = new LocalTemporary (ec, this.type);
8300                                         temp.Store (ec);
8301                                 }
8302
8303                                 if (is_stobj)
8304                                         ig.Emit (OpCodes.Stobj, t);
8305                                 else if (has_type_arg)
8306                                         ig.Emit (op, t);
8307                                 else
8308                                         ig.Emit (op);
8309                         } else {
8310                                 ModuleBuilder mb = CodeGen.Module.Builder;
8311                                 int arg_count = ea.Arguments.Count;
8312                                 Type [] args = new Type [arg_count + 1];
8313                                 MethodInfo set;
8314
8315                                 source.Emit (ec);
8316                                 if (leave_copy) {
8317                                         ec.ig.Emit (OpCodes.Dup);
8318                                         temp = new LocalTemporary (ec, this.type);
8319                                         temp.Store (ec);
8320                                 }
8321
8322                                 for (int i = 0; i < arg_count; i++){
8323                                         //args [i++] = a.Type;
8324                                         args [i] = TypeManager.int32_type;
8325                                 }
8326
8327                                 args [arg_count] = type;
8328
8329                                 set = mb.GetArrayMethod (
8330                                         ea.Expr.Type, "Set",
8331                                         CallingConventions.HasThis |
8332                                         CallingConventions.Standard,
8333                                         TypeManager.void_type, args);
8334
8335                                 ig.Emit (OpCodes.Call, set);
8336                         }
8337
8338                         if (temp != null)
8339                                 temp.Emit (ec);
8340                 }
8341
8342                 public void AddressOf (EmitContext ec, AddressOp mode)
8343                 {
8344                         int rank = ea.Expr.Type.GetArrayRank ();
8345                         ILGenerator ig = ec.ig;
8346
8347                         LoadArrayAndArguments (ec);
8348
8349                         if (rank == 1){
8350                                 ig.Emit (OpCodes.Ldelema, type);
8351                         } else {
8352                                 MethodInfo address = FetchAddressMethod ();
8353                                 ig.Emit (OpCodes.Call, address);
8354                         }
8355                 }
8356         }
8357
8358
8359         class Indexers {
8360                 public ArrayList Properties;
8361                 static Hashtable map;
8362
8363                 public struct Indexer {
8364                         public readonly Type Type;
8365                         public readonly MethodInfo Getter, Setter;
8366
8367                         public Indexer (Type type, MethodInfo get, MethodInfo set)
8368                         {
8369                                 this.Type = type;
8370                                 this.Getter = get;
8371                                 this.Setter = set;
8372                         }
8373                 }
8374
8375                 static Indexers ()
8376                 {
8377                         map = new Hashtable ();
8378                 }
8379
8380                 Indexers ()
8381                 {
8382                         Properties = new ArrayList ();
8383                 }
8384
8385                 void Append (MemberInfo [] mi)
8386                 {
8387                         foreach (PropertyInfo property in mi){
8388                                 MethodInfo get, set;
8389
8390                                 get = property.GetGetMethod (true);
8391                                 set = property.GetSetMethod (true);
8392                                 Properties.Add (new Indexer (property.PropertyType, get, set));
8393                         }
8394                 }
8395
8396                 static private MemberInfo [] GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
8397                 {
8398                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
8399
8400                         MemberInfo [] mi = TypeManager.MemberLookup (
8401                                 caller_type, caller_type, lookup_type, MemberTypes.Property,
8402                                 BindingFlags.Public | BindingFlags.Instance |
8403                                 BindingFlags.DeclaredOnly, p_name, null);
8404
8405                         if (mi == null || mi.Length == 0)
8406                                 return null;
8407
8408                         return mi;
8409                 }
8410
8411                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
8412                 {
8413                         Indexers ix = (Indexers) map [lookup_type];
8414
8415                         if (ix != null)
8416                                 return ix;
8417
8418                         Type copy = lookup_type;
8419                         while (copy != TypeManager.object_type && copy != null){
8420                                 MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, copy);
8421
8422                                 if (mi != null){
8423                                         if (ix == null)
8424                                                 ix = new Indexers ();
8425
8426                                         ix.Append (mi);
8427                                 }
8428
8429                                 copy = copy.BaseType;
8430                         }
8431
8432                         if (!lookup_type.IsInterface)
8433                                 return ix;
8434
8435                         Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
8436                         if (ifaces != null) {
8437                                 foreach (Type itype in ifaces) {
8438                                         MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, itype);
8439                                         if (mi != null){
8440                                                 if (ix == null)
8441                                                         ix = new Indexers ();
8442
8443                                                 ix.Append (mi);
8444                                         }
8445                                 }
8446                         }
8447
8448                         return ix;
8449                 }
8450         }
8451
8452         /// <summary>
8453         ///   Expressions that represent an indexer call.
8454         /// </summary>
8455         public class IndexerAccess : Expression, IAssignMethod {
8456                 //
8457                 // Points to our "data" repository
8458                 //
8459                 MethodInfo get, set;
8460                 ArrayList set_arguments;
8461                 bool is_base_indexer;
8462
8463                 protected Type indexer_type;
8464                 protected Type current_type;
8465                 protected Expression instance_expr;
8466                 protected ArrayList arguments;
8467
8468                 public IndexerAccess (ElementAccess ea, Location loc)
8469                         : this (ea.Expr, false, loc)
8470                 {
8471                         this.arguments = ea.Arguments;
8472                 }
8473
8474                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
8475                                          Location loc)
8476                 {
8477                         this.instance_expr = instance_expr;
8478                         this.is_base_indexer = is_base_indexer;
8479                         this.eclass = ExprClass.Value;
8480                         this.loc = loc;
8481                 }
8482
8483                 protected virtual bool CommonResolve (EmitContext ec)
8484                 {
8485                         indexer_type = instance_expr.Type;
8486                         current_type = ec.ContainerType;
8487
8488                         return true;
8489                 }
8490
8491                 public override Expression DoResolve (EmitContext ec)
8492                 {
8493                         ArrayList AllGetters = new ArrayList();
8494                         if (!CommonResolve (ec))
8495                                 return null;
8496
8497                         //
8498                         // Step 1: Query for all `Item' *properties*.  Notice
8499                         // that the actual methods are pointed from here.
8500                         //
8501                         // This is a group of properties, piles of them.
8502
8503                         bool found_any = false, found_any_getters = false;
8504                         Type lookup_type = indexer_type;
8505
8506                         Indexers ilist;
8507                         ilist = Indexers.GetIndexersForType (current_type, lookup_type, loc);
8508                         if (ilist != null) {
8509                                 found_any = true;
8510                                 if (ilist.Properties != null) {
8511                                         foreach (Indexers.Indexer ix in ilist.Properties) {
8512                                                 if (ix.Getter != null)
8513                                                         AllGetters.Add(ix.Getter);
8514                                         }
8515                                 }
8516                         }
8517
8518                         if (AllGetters.Count > 0) {
8519                                 found_any_getters = true;
8520                                 get = (MethodInfo) Invocation.OverloadResolve (
8521                                         ec, new MethodGroupExpr (AllGetters, loc),
8522                                         arguments, false, loc);
8523                         }
8524
8525                         if (!found_any) {
8526                                 Report.Error (21, loc,
8527                                               "Type `" + TypeManager.CSharpName (indexer_type) +
8528                                               "' does not have any indexers defined");
8529                                 return null;
8530                         }
8531
8532                         if (!found_any_getters) {
8533                                 Error (154, "indexer can not be used in this context, because " +
8534                                        "it lacks a `get' accessor");
8535                                 return null;
8536                         }
8537
8538                         if (get == null) {
8539                                 Error (1501, "No Overload for method `this' takes `" +
8540                                        arguments.Count + "' arguments");
8541                                 return null;
8542                         }
8543
8544                         //
8545                         // Only base will allow this invocation to happen.
8546                         //
8547                         if (get.IsAbstract && this is BaseIndexerAccess){
8548                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (get));
8549                                 return null;
8550                         }
8551
8552                         type = get.ReturnType;
8553                         if (type.IsPointer && !ec.InUnsafe){
8554                                 UnsafeError (loc);
8555                                 return null;
8556                         }
8557
8558                         instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
8559
8560                         eclass = ExprClass.IndexerAccess;
8561                         return this;
8562                 }
8563
8564                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8565                 {
8566                         ArrayList AllSetters = new ArrayList();
8567                         if (!CommonResolve (ec))
8568                                 return null;
8569
8570                         bool found_any = false, found_any_setters = false;
8571
8572                         Indexers ilist = Indexers.GetIndexersForType (current_type, indexer_type, loc);
8573                         if (ilist != null) {
8574                                 found_any = true;
8575                                 if (ilist.Properties != null) {
8576                                         foreach (Indexers.Indexer ix in ilist.Properties) {
8577                                                 if (ix.Setter != null)
8578                                                         AllSetters.Add(ix.Setter);
8579                                         }
8580                                 }
8581                         }
8582                         if (AllSetters.Count > 0) {
8583                                 found_any_setters = true;
8584                                 set_arguments = (ArrayList) arguments.Clone ();
8585                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
8586                                 set = (MethodInfo) Invocation.OverloadResolve (
8587                                         ec, new MethodGroupExpr (AllSetters, loc),
8588                                         set_arguments, false, loc);
8589                         }
8590
8591                         if (!found_any) {
8592                                 Report.Error (21, loc,
8593                                               "Type `" + TypeManager.CSharpName (indexer_type) +
8594                                               "' does not have any indexers defined");
8595                                 return null;
8596                         }
8597
8598                         if (!found_any_setters) {
8599                                 Error (154, "indexer can not be used in this context, because " +
8600                                        "it lacks a `set' accessor");
8601                                 return null;
8602                         }
8603
8604                         if (set == null) {
8605                                 Error (1501, "No Overload for method `this' takes `" +
8606                                        arguments.Count + "' arguments");
8607                                 return null;
8608                         }
8609
8610                         //
8611                         // Only base will allow this invocation to happen.
8612                         //
8613                         if (set.IsAbstract && this is BaseIndexerAccess){
8614                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (set));
8615                                 return null;
8616                         }
8617
8618                         //
8619                         // Now look for the actual match in the list of indexers to set our "return" type
8620                         //
8621                         type = TypeManager.void_type;   // default value
8622                         foreach (Indexers.Indexer ix in ilist.Properties){
8623                                 if (ix.Setter == set){
8624                                         type = ix.Type;
8625                                         break;
8626                                 }
8627                         }
8628
8629                         instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
8630
8631                         eclass = ExprClass.IndexerAccess;
8632                         return this;
8633                 }
8634
8635                 bool prepared = false;
8636                 LocalTemporary temp;
8637
8638                 public void Emit (EmitContext ec, bool leave_copy)
8639                 {
8640                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, get, arguments, loc, prepared, false);
8641                         if (leave_copy) {
8642                                 ec.ig.Emit (OpCodes.Dup);
8643                                 temp = new LocalTemporary (ec, Type);
8644                                 temp.Store (ec);
8645                         }
8646                 }
8647
8648                 //
8649                 // source is ignored, because we already have a copy of it from the
8650                 // LValue resolution and we have already constructed a pre-cached
8651                 // version of the arguments (ea.set_arguments);
8652                 //
8653                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8654                 {
8655                         prepared = prepare_for_load;
8656                         Argument a = (Argument) set_arguments [set_arguments.Count - 1];
8657
8658                         if (prepared) {
8659                                 source.Emit (ec);
8660                                 if (leave_copy) {
8661                                         ec.ig.Emit (OpCodes.Dup);
8662                                         temp = new LocalTemporary (ec, Type);
8663                                         temp.Store (ec);
8664                                 }
8665                         } else if (leave_copy) {
8666                                 temp = new LocalTemporary (ec, Type);
8667                                 source.Emit (ec);
8668                                 temp.Store (ec);
8669                                 a.Expr = temp;
8670                         }
8671
8672                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, set, set_arguments, loc, false, prepared);
8673
8674                         if (temp != null)
8675                                 temp.Emit (ec);
8676                 }
8677
8678
8679                 public override void Emit (EmitContext ec)
8680                 {
8681                         Emit (ec, false);
8682                 }
8683         }
8684
8685         /// <summary>
8686         ///   The base operator for method names
8687         /// </summary>
8688         public class BaseAccess : Expression {
8689                 string member;
8690
8691                 public BaseAccess (string member, Location l)
8692                 {
8693                         this.member = member;
8694                         loc = l;
8695                 }
8696
8697                 public override Expression DoResolve (EmitContext ec)
8698                 {
8699                         Expression c = CommonResolve (ec);
8700
8701                         if (c == null)
8702                                 return null;
8703
8704                         //
8705                         // MethodGroups use this opportunity to flag an error on lacking ()
8706                         //
8707                         if (!(c is MethodGroupExpr))
8708                                 return c.Resolve (ec);
8709                         return c;
8710                 }
8711
8712                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8713                 {
8714                         Expression c = CommonResolve (ec);
8715
8716                         if (c == null)
8717                                 return null;
8718
8719                         //
8720                         // MethodGroups use this opportunity to flag an error on lacking ()
8721                         //
8722                         if (! (c is MethodGroupExpr))
8723                                 return c.DoResolveLValue (ec, right_side);
8724
8725                         return c;
8726                 }
8727
8728                 Expression CommonResolve (EmitContext ec)
8729                 {
8730                         Expression member_lookup;
8731                         Type current_type = ec.ContainerType;
8732                         Type base_type = current_type.BaseType;
8733                         Expression e;
8734
8735                         if (ec.IsStatic){
8736                                 Error (1511, "Keyword base is not allowed in static method");
8737                                 return null;
8738                         }
8739
8740                         if (ec.IsFieldInitializer){
8741                                 Error (1512, "Keyword base is not available in the current context");
8742                                 return null;
8743                         }
8744
8745                         member_lookup = MemberLookup (ec, ec.ContainerType, null, base_type,
8746                                                       member, AllMemberTypes, AllBindingFlags,
8747                                                       loc);
8748                         if (member_lookup == null) {
8749                                 MemberLookupFailed (
8750                                         ec, base_type, base_type, member, null, loc);
8751                                 return null;
8752                         }
8753
8754                         Expression left;
8755
8756                         if (ec.IsStatic)
8757                                 left = new TypeExpression (base_type, loc);
8758                         else
8759                                 left = ec.GetThis (loc);
8760
8761                         e = MemberAccess.ResolveMemberAccess (ec, member_lookup, left, loc, null);
8762
8763                         if (e is PropertyExpr){
8764                                 PropertyExpr pe = (PropertyExpr) e;
8765
8766                                 pe.IsBase = true;
8767                         }
8768
8769                         if (e is MethodGroupExpr)
8770                                 ((MethodGroupExpr) e).IsBase = true;
8771
8772                         return e;
8773                 }
8774
8775                 public override void Emit (EmitContext ec)
8776                 {
8777                         throw new Exception ("Should never be called");
8778                 }
8779         }
8780
8781         /// <summary>
8782         ///   The base indexer operator
8783         /// </summary>
8784         public class BaseIndexerAccess : IndexerAccess {
8785                 public BaseIndexerAccess (ArrayList args, Location loc)
8786                         : base (null, true, loc)
8787                 {
8788                         arguments = new ArrayList ();
8789                         foreach (Expression tmp in args)
8790                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
8791                 }
8792
8793                 protected override bool CommonResolve (EmitContext ec)
8794                 {
8795                         instance_expr = ec.GetThis (loc);
8796
8797                         current_type = ec.ContainerType.BaseType;
8798                         indexer_type = current_type;
8799
8800                         foreach (Argument a in arguments){
8801                                 if (!a.Resolve (ec, loc))
8802                                         return false;
8803                         }
8804
8805                         return true;
8806                 }
8807         }
8808
8809         /// <summary>
8810         ///   This class exists solely to pass the Type around and to be a dummy
8811         ///   that can be passed to the conversion functions (this is used by
8812         ///   foreach implementation to typecast the object return value from
8813         ///   get_Current into the proper type.  All code has been generated and
8814         ///   we only care about the side effect conversions to be performed
8815         ///
8816         ///   This is also now used as a placeholder where a no-action expression
8817         ///   is needed (the `New' class).
8818         /// </summary>
8819         public class EmptyExpression : Expression {
8820                 public static readonly EmptyExpression Null = new EmptyExpression ();
8821
8822                 // TODO: should be protected
8823                 public EmptyExpression ()
8824                 {
8825                         type = TypeManager.object_type;
8826                         eclass = ExprClass.Value;
8827                         loc = Location.Null;
8828                 }
8829
8830                 public EmptyExpression (Type t)
8831                 {
8832                         type = t;
8833                         eclass = ExprClass.Value;
8834                         loc = Location.Null;
8835                 }
8836
8837                 public override Expression DoResolve (EmitContext ec)
8838                 {
8839                         return this;
8840                 }
8841
8842                 public override void Emit (EmitContext ec)
8843                 {
8844                         // nothing, as we only exist to not do anything.
8845                 }
8846
8847                 //
8848                 // This is just because we might want to reuse this bad boy
8849                 // instead of creating gazillions of EmptyExpressions.
8850                 // (CanImplicitConversion uses it)
8851                 //
8852                 public void SetType (Type t)
8853                 {
8854                         type = t;
8855                 }
8856         }
8857
8858         public class UserCast : Expression {
8859                 MethodBase method;
8860                 Expression source;
8861
8862                 public UserCast (MethodInfo method, Expression source, Location l)
8863                 {
8864                         this.method = method;
8865                         this.source = source;
8866                         type = method.ReturnType;
8867                         eclass = ExprClass.Value;
8868                         loc = l;
8869                 }
8870
8871                 public Expression Source {
8872                         get {
8873                                 return source;
8874                         }
8875                 }
8876
8877                 public override Expression DoResolve (EmitContext ec)
8878                 {
8879                         //
8880                         // We are born fully resolved
8881                         //
8882                         return this;
8883                 }
8884
8885                 public override void Emit (EmitContext ec)
8886                 {
8887                         ILGenerator ig = ec.ig;
8888
8889                         source.Emit (ec);
8890
8891                         if (method is MethodInfo)
8892                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
8893                         else
8894                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
8895
8896                 }
8897         }
8898
8899         // <summary>
8900         //   This class is used to "construct" the type during a typecast
8901         //   operation.  Since the Type.GetType class in .NET can parse
8902         //   the type specification, we just use this to construct the type
8903         //   one bit at a time.
8904         // </summary>
8905         public class ComposedCast : TypeExpr {
8906                 Expression left;
8907                 string dim;
8908
8909                 public ComposedCast (Expression left, string dim, Location l)
8910                 {
8911                         this.left = left;
8912                         this.dim = dim;
8913                         loc = l;
8914                 }
8915
8916                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
8917                 {
8918                         TypeExpr lexpr = left.ResolveAsTypeTerminal (ec);
8919                         if (lexpr == null)
8920                                 return null;
8921
8922                         Type ltype = lexpr.Type;
8923
8924                         if ((ltype == TypeManager.void_type) && (dim != "*")) {
8925                                 Report.Error (1547, Location,
8926                                               "Keyword 'void' cannot be used in this context");
8927                                 return null;
8928                         }
8929
8930                         if ((dim.Length > 0) && (dim [0] == '?')) {
8931                                 TypeExpr nullable = new NullableType (left, loc);
8932                                 if (dim.Length > 1)
8933                                         nullable = new ComposedCast (nullable, dim.Substring (1), loc);
8934                                 return nullable.ResolveAsTypeTerminal (ec);
8935                         }
8936
8937                         int pos = 0;
8938                         while ((pos < dim.Length) && (dim [pos] == '[')) {
8939                                 pos++;
8940
8941                                 if (dim [pos] == ']') {
8942                                         ltype = ltype.MakeArrayType ();
8943                                         pos++;
8944
8945                                         if (pos < dim.Length)
8946                                                 continue;
8947
8948                                         type = ltype;
8949                                         eclass = ExprClass.Type;
8950                                         return this;
8951                                 }
8952
8953                                 int rank = 0;
8954                                 while (dim [pos] == ',') {
8955                                         pos++; rank++;
8956                                 }
8957
8958                                 if ((dim [pos] != ']') || (pos != dim.Length-1))
8959                                         return null;
8960
8961                                 type = ltype.MakeArrayType (rank + 1);
8962                                 eclass = ExprClass.Type;
8963                                 return this;
8964                         }
8965
8966                         if (dim != "") {
8967                                 //
8968                                 // ltype.Fullname is already fully qualified, so we can skip
8969                                 // a lot of probes, and go directly to TypeManager.LookupType
8970                                 //
8971                                 string fname = ltype.FullName != null ? ltype.FullName : ltype.Name;
8972                                 string cname = fname + dim;
8973                                 type = TypeManager.LookupTypeDirect (cname);
8974                                 if (type == null){
8975                                         //
8976                                         // For arrays of enumerations we are having a problem
8977                                         // with the direct lookup.  Need to investigate.
8978                                         //
8979                                         // For now, fall back to the full lookup in that case.
8980                                         //
8981                                         FullNamedExpression e = ec.DeclSpace.LookupType (cname, false, loc);
8982                                         if (e is TypeExpr)
8983                                                 type = ((TypeExpr) e).ResolveType (ec);
8984                                         if (type == null)
8985                                                 return null;
8986                                 }
8987                         } else {
8988                                 type = ltype;
8989                         }
8990
8991                         if (!ec.InUnsafe && type.IsPointer){
8992                                 UnsafeError (loc);
8993                                 return null;
8994                         }
8995
8996                         if (type.IsArray && (type.GetElementType () == TypeManager.arg_iterator_type ||
8997                                 type.GetElementType () == TypeManager.typed_reference_type)) {
8998                                 Report.Error (611, loc, "Array elements cannot be of type '{0}'", TypeManager.CSharpName (type.GetElementType ()));
8999                                 return null;
9000                         }
9001
9002                         eclass = ExprClass.Type;
9003                         return this;
9004                 }
9005
9006                 public override string Name {
9007                         get {
9008                                 return left + dim;
9009                         }
9010                 }
9011
9012                 public override string FullName {
9013                         get {
9014                                 return type.FullName;
9015                         }
9016                 }
9017         }
9018
9019         public class FixedBufferPtr: Expression {
9020                 Expression array;
9021
9022                 public FixedBufferPtr (Expression array, Type array_type, Location l)
9023                 {
9024                         this.array = array;
9025                         this.loc = l;
9026
9027                         type = TypeManager.GetPointerType (array_type);
9028                         eclass = ExprClass.Value;
9029                 }
9030
9031                 public override void Emit(EmitContext ec)
9032                 {
9033                         array.Emit (ec);
9034                 }
9035
9036                 public override Expression DoResolve (EmitContext ec)
9037                 {
9038                         //
9039                         // We are born fully resolved
9040                         //
9041                         return this;
9042                 }
9043         }
9044
9045
9046         //
9047         // This class is used to represent the address of an array, used
9048         // only by the Fixed statement, this generates "&a [0]" construct
9049         // for fixed (char *pa = a)
9050         //
9051         public class ArrayPtr : FixedBufferPtr {
9052                 Type array_type;
9053
9054                 public ArrayPtr (Expression array, Type array_type, Location l):
9055                         base (array, array_type, l)
9056                 {
9057                         this.array_type = array_type;
9058                 }
9059
9060                 public override void Emit (EmitContext ec)
9061                 {
9062                         base.Emit (ec);
9063
9064                         ILGenerator ig = ec.ig;
9065                         IntLiteral.EmitInt (ig, 0);
9066                         ig.Emit (OpCodes.Ldelema, array_type);
9067                 }
9068         }
9069
9070         //
9071         // Used by the fixed statement
9072         //
9073         public class StringPtr : Expression {
9074                 LocalBuilder b;
9075
9076                 public StringPtr (LocalBuilder b, Location l)
9077                 {
9078                         this.b = b;
9079                         eclass = ExprClass.Value;
9080                         type = TypeManager.char_ptr_type;
9081                         loc = l;
9082                 }
9083
9084                 public override Expression DoResolve (EmitContext ec)
9085                 {
9086                         // This should never be invoked, we are born in fully
9087                         // initialized state.
9088
9089                         return this;
9090                 }
9091
9092                 public override void Emit (EmitContext ec)
9093                 {
9094                         ILGenerator ig = ec.ig;
9095
9096                         ig.Emit (OpCodes.Ldloc, b);
9097                         ig.Emit (OpCodes.Conv_I);
9098                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
9099                         ig.Emit (OpCodes.Add);
9100                 }
9101         }
9102
9103         //
9104         // Implements the `stackalloc' keyword
9105         //
9106         public class StackAlloc : Expression {
9107                 Type otype;
9108                 Expression t;
9109                 Expression count;
9110
9111                 public StackAlloc (Expression type, Expression count, Location l)
9112                 {
9113                         t = type;
9114                         this.count = count;
9115                         loc = l;
9116                 }
9117
9118                 public override Expression DoResolve (EmitContext ec)
9119                 {
9120                         count = count.Resolve (ec);
9121                         if (count == null)
9122                                 return null;
9123
9124                         if (count.Type != TypeManager.int32_type){
9125                                 count = Convert.ImplicitConversionRequired (ec, count, TypeManager.int32_type, loc);
9126                                 if (count == null)
9127                                         return null;
9128                         }
9129
9130                         Constant c = count as Constant;
9131                         if (c != null && c.IsNegative) {
9132                                 Report.Error (247, loc, "Cannot use a negative size with stackalloc");
9133                                 return null;
9134                         }
9135
9136                         if (ec.CurrentBranching.InCatch () ||
9137                             ec.CurrentBranching.InFinally (true)) {
9138                                 Error (255,
9139                                               "stackalloc can not be used in a catch or finally block");
9140                                 return null;
9141                         }
9142
9143                         TypeExpr texpr = t.ResolveAsTypeTerminal (ec);
9144                         if (texpr == null)
9145                                 return null;
9146
9147                         otype = texpr.Type;
9148
9149                         if (!TypeManager.VerifyUnManaged (otype, loc))
9150                                 return null;
9151
9152                         type = TypeManager.GetPointerType (otype);
9153                         eclass = ExprClass.Value;
9154
9155                         return this;
9156                 }
9157
9158                 public override void Emit (EmitContext ec)
9159                 {
9160                         int size = GetTypeSize (otype);
9161                         ILGenerator ig = ec.ig;
9162
9163                         if (size == 0)
9164                                 ig.Emit (OpCodes.Sizeof, otype);
9165                         else
9166                                 IntConstant.EmitInt (ig, size);
9167                         count.Emit (ec);
9168                         ig.Emit (OpCodes.Mul);
9169                         ig.Emit (OpCodes.Localloc);
9170                 }
9171         }
9172 }