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 (!ec.InUnsafe) {
 420                                         UnsafeError (loc);
 421                                         return null;
 422                                 }
 423
 424                                 if (!TypeManager.VerifyUnManaged (Expr.Type, loc)){
 425                                         return null;
 426                                 }
 427
 428                                 IVariable variable = Expr as IVariable;
 429                                 bool is_fixed = variable != null && variable.VerifyFixed (false);
 430
 431                                 if (!ec.InFixedInitializer && !is_fixed) {
 432                                         Error (212, "You can only take the address of an unfixed expression inside " +
 433                                                "of a fixed statement initializer");
 434                                         return null;
 435                                 }
 436
 437                                 if (ec.InFixedInitializer && is_fixed) {
 438                                         Error (213, "You can not fix an already fixed expression");
 439                                         return null;
 440                                 }
 441
 442                                 LocalVariableReference lr = Expr as LocalVariableReference;
 443                                 if (lr != null){
 444                                         if (lr.local_info.IsCaptured){
 445                                                 AnonymousMethod.Error_AddressOfCapturedVar (lr.Name, loc);
 446                                                 return null;
 447                                         }
 448                                         lr.local_info.AddressTaken = true;
 449                                         lr.local_info.Used = true;
 450                                 }
 451
 452                                 // According to the specs, a variable is considered definitely assigned if you take
 453                                 // its address.
 454                                 if ((variable != null) && (variable.VariableInfo != null))
 455                                         variable.VariableInfo.SetAssigned (ec);
 456
 457                                 type = TypeManager.GetPointerType (Expr.Type);
 458                                 return this;
 459
 460                         case Operator.Indirection:
 461                                 if (!ec.InUnsafe){
 462                                         UnsafeError (loc);
 463                                         return null;
 464                                 }
 465
 466                                 if (!expr_type.IsPointer){
 467                                         Error (193, "The * or -> operator can only be applied to pointers");
 468                                         return null;
 469                                 }
 470
 471                                 //
 472                                 // We create an Indirection expression, because
 473                                 // it can implement the IMemoryLocation.
 474                                 //
 475                                 return new Indirection (Expr, loc);
 476
 477                         case Operator.UnaryPlus:
 478                                 //
 479                                 // A plus in front of something is just a no-op, so return the child.
 480                                 //
 481                                 return Expr;
 482
 483                         case Operator.UnaryNegation:
 484                                 //
 485                                 // Deals with -literals
 486                                 // int     operator- (int x)
 487                                 // long    operator- (long x)
 488                                 // float   operator- (float f)
 489                                 // double  operator- (double d)
 490                                 // decimal operator- (decimal d)
 491                                 //
 492                                 Expression expr = null;
 493
 494                                 //
 495                                 // transform - - expr into expr
 496                                 //
 497                                 if (Expr is Unary){
 498                                         Unary unary = (Unary) Expr;
 499
 500                                         if (unary.Oper == Operator.UnaryNegation)
 501                                                 return unary.Expr;
 502                                 }
 503
 504                                 //
 505                                 // perform numeric promotions to int,
 506                                 // long, double.
 507                                 //
 508                                 //
 509                                 // The following is inneficient, because we call
 510                                 // ImplicitConversion too many times.
 511                                 //
 512                                 // It is also not clear if we should convert to Float
 513                                 // or Double initially.
 514                                 //
 515                                 if (expr_type == TypeManager.uint32_type){
 516                                         //
 517                                         // FIXME: handle exception to this rule that
 518                                         // permits the int value -2147483648 (-2^31) to
 519                                         // bt wrote as a decimal interger literal
 520                                         //
 521                                         type = TypeManager.int64_type;
 522                                         Expr = Convert.ImplicitConversion (ec, Expr, type, loc);
 523                                         return this;
 524                                 }
 525
 526                                 if (expr_type == TypeManager.uint64_type){
 527                                         //
 528                                         // FIXME: Handle exception of `long value'
 529                                         // -92233720368547758087 (-2^63) to be wrote as
 530                                         // decimal integer literal.
 531                                         //
 532                                         Error23 (expr_type);
 533                                         return null;
 534                                 }
 535
 536                                 if (expr_type == TypeManager.float_type){
 537                                         type = expr_type;
 538                                         return this;
 539                                 }
 540
 541                                 expr = Convert.ImplicitConversion (ec, Expr, TypeManager.int32_type, loc);
 542                                 if (expr != null){
 543                                         Expr = expr;
 544                                         type = expr.Type;
 545                                         return this;
 546                                 }
 547
 548                                 expr = Convert.ImplicitConversion (ec, Expr, TypeManager.int64_type, loc);
 549                                 if (expr != null){
 550                                         Expr = expr;
 551                                         type = expr.Type;
 552                                         return this;
 553                                 }
 554
 555                                 expr = Convert.ImplicitConversion (ec, Expr, TypeManager.double_type, loc);
 556                                 if (expr != null){
 557                                         Expr = expr;
 558                                         type = expr.Type;
 559                                         return this;
 560                                 }
 561
 562                                 Error23 (expr_type);
 563                                 return null;
 564                         }
 565
 566                         Error (187, "No such operator '" + OperName (Oper) + "' defined for type '" +
 567                                TypeManager.CSharpName (expr_type) + "'");
 568                         return null;
 569                 }
 570
 571                 public override Expression DoResolve (EmitContext ec)
 572                 {
 573                         if (Oper == Operator.AddressOf) {
 574                                 Expr = Expr.DoResolveLValue (ec, new EmptyExpression ());
 575
 576                                 if (Expr == null || Expr.eclass != ExprClass.Variable){
 577                                         Error (211, "Cannot take the address of non-variables");
 578                                         return null;
 579                                 }
 580                         }
 581                         else
 582                                 Expr = Expr.Resolve (ec);
 583
 584                         if (Expr == null)
 585                                 return null;
 586
 587                         if (TypeManager.IsNullableType (Expr.Type))
 588                                 return new Nullable.LiftedUnaryOperator (Oper, Expr, loc).Resolve (ec);
 589
 590                         eclass = ExprClass.Value;
 591                         return ResolveOperator (ec);
 592                 }
 593
 594                 public override Expression DoResolveLValue (EmitContext ec, Expression right)
 595                 {
 596                         if (Oper == Operator.Indirection)
 597                                 return DoResolve (ec);
 598
 599                         return null;
 600                 }
 601
 602                 public override void Emit (EmitContext ec)
 603                 {
 604                         ILGenerator ig = ec.ig;
 605
 606                         switch (Oper) {
 607                         case Operator.UnaryPlus:
 608                                 throw new Exception ("This should be caught by Resolve");
 609
 610                         case Operator.UnaryNegation:
 611                                 if (ec.CheckState) {
 612                                         ig.Emit (OpCodes.Ldc_I4_0);
 613                                         if (type == TypeManager.int64_type)
 614                                                 ig.Emit (OpCodes.Conv_U8);
 615                                         Expr.Emit (ec);
 616                                         ig.Emit (OpCodes.Sub_Ovf);
 617                                 } else {
 618                                 Expr.Emit (ec);
 619                                 ig.Emit (OpCodes.Neg);
 620                                 }
 621
 622                                 break;
 623
 624                         case Operator.LogicalNot:
 625                                 Expr.Emit (ec);
 626                                 ig.Emit (OpCodes.Ldc_I4_0);
 627                                 ig.Emit (OpCodes.Ceq);
 628                                 break;
 629
 630                         case Operator.OnesComplement:
 631                                 Expr.Emit (ec);
 632                                 ig.Emit (OpCodes.Not);
 633                                 break;
 634
 635                         case Operator.AddressOf:
 636                                 ((IMemoryLocation)Expr).AddressOf (ec, AddressOp.LoadStore);
 637                                 break;
 638
 639                         default:
 640                                 throw new Exception ("This should not happen: Operator = "
 641                                                      + Oper.ToString ());
 642                         }
 643                 }
 644
 645                 public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
 646                 {
 647                         if (Oper == Operator.LogicalNot)
 648                                 Expr.EmitBranchable (ec, target, !onTrue);
 649                         else
 650                                 base.EmitBranchable (ec, target, onTrue);
 651                 }
 652
 653                 public override string ToString ()
 654                 {
 655                         return "Unary (" + Oper + ", " + Expr + ")";
 656                 }
 657
 658         }
 659
 660         //
 661         // Unary operators are turned into Indirection expressions
 662         // after semantic analysis (this is so we can take the address
 663         // of an indirection).
 664         //
 665         public class Indirection : Expression, IMemoryLocation, IAssignMethod, IVariable {
 666                 Expression expr;
 667                 LocalTemporary temporary;
 668                 bool prepared;
 669
 670                 public Indirection (Expression expr, Location l)
 671                 {
 672                         this.expr = expr;
 673                         type = TypeManager.HasElementType (expr.Type) ? TypeManager.GetElementType (expr.Type) : expr.Type;
 674                         eclass = ExprClass.Variable;
 675                         loc = l;
 676                 }
 677
 678                 public override void Emit (EmitContext ec)
 679                 {
 680                         if (!prepared)
 681                                 expr.Emit (ec);
 682
 683                         LoadFromPtr (ec.ig, Type);
 684                 }
 685
 686                 public void Emit (EmitContext ec, bool leave_copy)
 687                 {
 688                         Emit (ec);
 689                         if (leave_copy) {
 690                                 ec.ig.Emit (OpCodes.Dup);
 691                                 temporary = new LocalTemporary (ec, expr.Type);
 692                                 temporary.Store (ec);
 693                         }
 694                 }
 695
 696                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 697                 {
 698                         prepared = prepare_for_load;
 699
 700                         expr.Emit (ec);
 701
 702                         if (prepare_for_load)
 703                                 ec.ig.Emit (OpCodes.Dup);
 704
 705                         source.Emit (ec);
 706                         if (leave_copy) {
 707                                 ec.ig.Emit (OpCodes.Dup);
 708                                 temporary = new LocalTemporary (ec, expr.Type);
 709                                 temporary.Store (ec);
 710                         }
 711
 712                         StoreFromPtr (ec.ig, type);
 713
 714                         if (temporary != null)
 715                                 temporary.Emit (ec);
 716                 }
 717
 718                 public void AddressOf (EmitContext ec, AddressOp Mode)
 719                 {
 720                         expr.Emit (ec);
 721                 }
 722
 723                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
 724                 {
 725                         return DoResolve (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                 /// <summary>
 810                 ///   Returns whether an object of type `t' can be incremented
 811                 ///   or decremented with add/sub (ie, basically whether we can
 812                 ///   use pre-post incr-decr operations on it, but it is not a
 813                 ///   System.Decimal, which we require operator overloading to catch)
 814                 /// </summary>
 815                 static bool IsIncrementableNumber (Type t)
 816                 {
 817                         return (t == TypeManager.sbyte_type) ||
 818                                 (t == TypeManager.byte_type) ||
 819                                 (t == TypeManager.short_type) ||
 820                                 (t == TypeManager.ushort_type) ||
 821                                 (t == TypeManager.int32_type) ||
 822                                 (t == TypeManager.uint32_type) ||
 823                                 (t == TypeManager.int64_type) ||
 824                                 (t == TypeManager.uint64_type) ||
 825                                 (t == TypeManager.char_type) ||
 826                                 (t.IsSubclassOf (TypeManager.enum_type)) ||
 827                                 (t == TypeManager.float_type) ||
 828                                 (t == TypeManager.double_type) ||
 829                                 (t.IsPointer && t != TypeManager.void_ptr_type);
 830                 }
 831
 832                 Expression ResolveOperator (EmitContext ec)
 833                 {
 834                         Type expr_type = expr.Type;
 835
 836                         //
 837                         // Step 1: Perform Operator Overload location
 838                         //
 839                         Expression mg;
 840                         string op_name;
 841
 842                         if (mode == Mode.PreIncrement || mode == Mode.PostIncrement)
 843                                 op_name = "op_Increment";
 844                         else
 845                                 op_name = "op_Decrement";
 846
 847                         mg = MemberLookup (ec, expr_type, op_name, MemberTypes.Method, AllBindingFlags, loc);
 848
 849                         if (mg != null) {
 850                                 method = StaticCallExpr.MakeSimpleCall (
 851                                         ec, (MethodGroupExpr) mg, expr, loc);
 852
 853                                 type = method.Type;
 854                         } else if (!IsIncrementableNumber (expr_type)) {
 855                                 Error (187, "No such operator '" + OperName (mode) + "' defined for type '" +
 856                                        TypeManager.CSharpName (expr_type) + "'");
 857                                    return null;
 858                         }
 859
 860                         //
 861                         // The operand of the prefix/postfix increment decrement operators
 862                         // should be an expression that is classified as a variable,
 863                         // a property access or an indexer access
 864                         //
 865                         type = expr_type;
 866                         if (expr.eclass == ExprClass.Variable){
 867                                 LocalVariableReference var = expr as LocalVariableReference;
 868                                 if ((var != null) && var.IsReadOnly) {
 869                                         Error (1604, "cannot assign to `" + var.Name + "' because it is readonly");
 870                                         return null;
 871                                 }
 872                         } else if (expr.eclass == ExprClass.IndexerAccess || expr.eclass == ExprClass.PropertyAccess){
 873                                 expr = expr.ResolveLValue (ec, this);
 874                                 if (expr == null)
 875                                         return null;
 876                         } else {
 877                                 expr.Error_UnexpectedKind ("variable, indexer or property access", loc);
 878                                 return null;
 879                         }
 880
 881                         return this;
 882                 }
 883
 884                 public override Expression DoResolve (EmitContext ec)
 885                 {
 886                         expr = expr.Resolve (ec);
 887
 888                         if (expr == null)
 889                                 return null;
 890
 891                         eclass = ExprClass.Value;
 892
 893                         if (TypeManager.IsNullableType (expr.Type))
 894                                 return new Nullable.LiftedUnaryMutator (mode, expr, loc).Resolve (ec);
 895
 896                         return ResolveOperator (ec);
 897                 }
 898
 899                 static int PtrTypeSize (Type t)
 900                 {
 901                         return GetTypeSize (TypeManager.GetElementType (t));
 902                 }
 903
 904                 //
 905                 // Loads the proper "1" into the stack based on the type, then it emits the
 906                 // opcode for the operation requested
 907                 //
 908                 void LoadOneAndEmitOp (EmitContext ec, Type t)
 909                 {
 910                         //
 911                         // Measure if getting the typecode and using that is more/less efficient
 912                         // that comparing types.  t.GetTypeCode() is an internal call.
 913                         //
 914                         ILGenerator ig = ec.ig;
 915
 916                         if (t == TypeManager.uint64_type || t == TypeManager.int64_type)
 917                                 LongConstant.EmitLong (ig, 1);
 918                         else if (t == TypeManager.double_type)
 919                                 ig.Emit (OpCodes.Ldc_R8, 1.0);
 920                         else if (t == TypeManager.float_type)
 921                                 ig.Emit (OpCodes.Ldc_R4, 1.0F);
 922                         else if (t.IsPointer){
 923                                 int n = PtrTypeSize (t);
 924
 925                                 if (n == 0)
 926                                         ig.Emit (OpCodes.Sizeof, t);
 927                                 else
 928                                         IntConstant.EmitInt (ig, n);
 929                         } else
 930                                 ig.Emit (OpCodes.Ldc_I4_1);
 931
 932                         //
 933                         // Now emit the operation
 934                         //
 935                         if (ec.CheckState){
 936                                 if (t == TypeManager.int32_type ||
 937                                     t == TypeManager.int64_type){
 938                                         if ((mode & Mode.IsDecrement) != 0)
 939                                                 ig.Emit (OpCodes.Sub_Ovf);
 940                                         else
 941                                                 ig.Emit (OpCodes.Add_Ovf);
 942                                 } else if (t == TypeManager.uint32_type ||
 943                                            t == TypeManager.uint64_type){
 944                                         if ((mode & Mode.IsDecrement) != 0)
 945                                                 ig.Emit (OpCodes.Sub_Ovf_Un);
 946                                         else
 947                                                 ig.Emit (OpCodes.Add_Ovf_Un);
 948                                 } else {
 949                                         if ((mode & Mode.IsDecrement) != 0)
 950                                                 ig.Emit (OpCodes.Sub_Ovf);
 951                                         else
 952                                                 ig.Emit (OpCodes.Add_Ovf);
 953                                 }
 954                         } else {
 955                                 if ((mode & Mode.IsDecrement) != 0)
 956                                         ig.Emit (OpCodes.Sub);
 957                                 else
 958                                         ig.Emit (OpCodes.Add);
 959                         }
 960
 961                         if (t == TypeManager.sbyte_type){
 962                                 if (ec.CheckState)
 963                                         ig.Emit (OpCodes.Conv_Ovf_I1);
 964                                 else
 965                                         ig.Emit (OpCodes.Conv_I1);
 966                         } else if (t == TypeManager.byte_type){
 967                                 if (ec.CheckState)
 968                                         ig.Emit (OpCodes.Conv_Ovf_U1);
 969                                 else
 970                                         ig.Emit (OpCodes.Conv_U1);
 971                         } else if (t == TypeManager.short_type){
 972                                 if (ec.CheckState)
 973                                         ig.Emit (OpCodes.Conv_Ovf_I2);
 974                                 else
 975                                         ig.Emit (OpCodes.Conv_I2);
 976                         } else if (t == TypeManager.ushort_type || t == TypeManager.char_type){
 977                                 if (ec.CheckState)
 978                                         ig.Emit (OpCodes.Conv_Ovf_U2);
 979                                 else
 980                                         ig.Emit (OpCodes.Conv_U2);
 981                         }
 982
 983                 }
 984
 985                 void EmitCode (EmitContext ec, bool is_expr)
 986                 {
 987                         recurse = true;
 988                         this.is_expr = is_expr;
 989                         ((IAssignMethod) expr).EmitAssign (ec, this, is_expr && (mode == Mode.PreIncrement || mode == Mode.PreDecrement), true);
 990                 }
 991
 992                 public override void Emit (EmitContext ec)
 993                 {
 994                         //
 995                         // We use recurse to allow ourselfs to be the source
 996                         // of an assignment. This little hack prevents us from
 997                         // having to allocate another expression
 998                         //
 999                         if (recurse) {
1000                                 ((IAssignMethod) expr).Emit (ec, is_expr && (mode == Mode.PostIncrement  || mode == Mode.PostDecrement));
1001                                 if (method == null)
1002                                         LoadOneAndEmitOp (ec, expr.Type);
1003                                 else
1004                                         ec.ig.Emit (OpCodes.Call, method.Method);
1005                                 recurse = false;
1006                                 return;
1007                         }
1008
1009                         EmitCode (ec, true);
1010                 }
1011
1012                 public override void EmitStatement (EmitContext ec)
1013                 {
1014                         EmitCode (ec, false);
1015                 }
1016         }
1017
1018         /// <summary>
1019         ///   Base class for the `Is' and `As' classes.
1020         /// </summary>
1021         ///
1022         /// <remarks>
1023         ///   FIXME: Split this in two, and we get to save the `Operator' Oper
1024         ///   size.
1025         /// </remarks>
1026         public abstract class Probe : Expression {
1027                 public Expression ProbeType;
1028                 protected Expression expr;
1029                 protected Type probe_type;
1030
1031                 public Probe (Expression expr, Expression probe_type, Location l)
1032                 {
1033                         ProbeType = probe_type;
1034                         loc = l;
1035                         this.expr = expr;
1036                 }
1037
1038                 public Expression Expr {
1039                         get {
1040                                 return expr;
1041                         }
1042                 }
1043
1044                 public override Expression DoResolve (EmitContext ec)
1045                 {
1046                         TypeExpr texpr = ProbeType.ResolveAsTypeTerminal (ec);
1047                         if (texpr == null)
1048                                 return null;
1049                         probe_type = texpr.Type;
1050
1051                         CheckObsoleteAttribute (probe_type);
1052
1053                         expr = expr.Resolve (ec);
1054                         if (expr == null)
1055                                 return null;
1056
1057                         if (expr.Type.IsPointer) {
1058                                 Report.Error (244, loc, "\"is\" or \"as\" are not valid on pointer types");
1059                                 return null;
1060                         }
1061                         return this;
1062                 }
1063         }
1064
1065         /// <summary>
1066         ///   Implementation of the `is' operator.
1067         /// </summary>
1068         public class Is : Probe {
1069                 public Is (Expression expr, Expression probe_type, Location l)
1070                         : base (expr, probe_type, l)
1071                 {
1072                 }
1073
1074                 enum Action {
1075                         AlwaysTrue, AlwaysNull, AlwaysFalse, LeaveOnStack, Probe
1076                 }
1077
1078                 Action action;
1079
1080                 public override void Emit (EmitContext ec)
1081                 {
1082                         ILGenerator ig = ec.ig;
1083
1084                         expr.Emit (ec);
1085
1086                         switch (action){
1087                         case Action.AlwaysFalse:
1088                                 ig.Emit (OpCodes.Pop);
1089                                 IntConstant.EmitInt (ig, 0);
1090                                 return;
1091                         case Action.AlwaysTrue:
1092                                 ig.Emit (OpCodes.Pop);
1093                                 IntConstant.EmitInt (ig, 1);
1094                                 return;
1095                         case Action.LeaveOnStack:
1096                                 // the `e != null' rule.
1097                                 ig.Emit (OpCodes.Ldnull);
1098                                 ig.Emit (OpCodes.Ceq);
1099                                 ig.Emit (OpCodes.Ldc_I4_0);
1100                                 ig.Emit (OpCodes.Ceq);
1101                                 return;
1102                         case Action.Probe:
1103                                 ig.Emit (OpCodes.Isinst, probe_type);
1104                                 ig.Emit (OpCodes.Ldnull);
1105                                 ig.Emit (OpCodes.Cgt_Un);
1106                                 return;
1107                         }
1108                         throw new Exception ("never reached");
1109                 }
1110
1111                 public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
1112                 {
1113                         ILGenerator ig = ec.ig;
1114
1115                         switch (action){
1116                         case Action.AlwaysFalse:
1117                                 if (! onTrue)
1118                                         ig.Emit (OpCodes.Br, target);
1119
1120                                 return;
1121                         case Action.AlwaysTrue:
1122                                 if (onTrue)
1123                                         ig.Emit (OpCodes.Br, target);
1124
1125                                 return;
1126                         case Action.LeaveOnStack:
1127                                 // the `e != null' rule.
1128                                 expr.Emit (ec);
1129                                 ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
1130                                 return;
1131                         case Action.Probe:
1132                                 expr.Emit (ec);
1133                                 ig.Emit (OpCodes.Isinst, probe_type);
1134                                 ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
1135                                 return;
1136                         }
1137                         throw new Exception ("never reached");
1138                 }
1139
1140                 public override Expression DoResolve (EmitContext ec)
1141                 {
1142                         Expression e = base.DoResolve (ec);
1143
1144                         if ((e == null) || (expr == null))
1145                                 return null;
1146
1147                         Type etype = expr.Type;
1148                         bool warning_always_matches = false;
1149                         bool warning_never_matches = false;
1150
1151                         type = TypeManager.bool_type;
1152                         eclass = ExprClass.Value;
1153
1154                         //
1155                         // First case, if at compile time, there is an implicit conversion
1156                         // then e != null (objects) or true (value types)
1157                         //
1158                         e = Convert.ImplicitConversionStandard (ec, expr, probe_type, loc);
1159                         if (e != null){
1160                                 expr = e;
1161                                 if (etype.IsValueType)
1162                                         action = Action.AlwaysTrue;
1163                                 else
1164                                         action = Action.LeaveOnStack;
1165
1166                                 warning_always_matches = true;
1167                         } else if (Convert.ExplicitReferenceConversionExists (etype, probe_type)){
1168                                 if (etype.IsGenericParameter)
1169                                         expr = new BoxedCast (expr, etype);
1170
1171                                 //
1172                                 // Second case: explicit reference convresion
1173                                 //
1174                                 if (expr is NullLiteral)
1175                                         action = Action.AlwaysFalse;
1176                                 else
1177                                         action = Action.Probe;
1178                         } else {
1179                                 action = Action.AlwaysFalse;
1180                                 warning_never_matches = true;
1181                         }
1182
1183                         if (warning_always_matches)
1184                                 Warning (183, "The given expression is always of the provided ('{0}') type", TypeManager.CSharpName (probe_type));
1185                         else if (warning_never_matches){
1186                                 if (!(probe_type.IsInterface || expr.Type.IsInterface))
1187                                         Warning (184, "The given expression is never of the provided ('{0}') type", TypeManager.CSharpName (probe_type));
1188                         }
1189
1190                         return this;
1191                 }
1192         }
1193
1194         /// <summary>
1195         ///   Implementation of the `as' operator.
1196         /// </summary>
1197         public class As : Probe {
1198                 public As (Expression expr, Expression probe_type, Location l)
1199                         : base (expr, probe_type, l)
1200                 {
1201                 }
1202
1203                 bool do_isinst = false;
1204
1205                 public override void Emit (EmitContext ec)
1206                 {
1207                         ILGenerator ig = ec.ig;
1208
1209                         expr.Emit (ec);
1210
1211                         if (do_isinst)
1212                                 ig.Emit (OpCodes.Isinst, probe_type);
1213                 }
1214
1215                 static void Error_CannotConvertType (Type source, Type target, Location loc)
1216                 {
1217                         Report.Error (
1218                                 39, loc, "as operator can not convert from `" +
1219                                 TypeManager.CSharpName (source) + "' to `" +
1220                                 TypeManager.CSharpName (target) + "'");
1221                 }
1222
1223                 public override Expression DoResolve (EmitContext ec)
1224                 {
1225                         Expression e = base.DoResolve (ec);
1226
1227                         if (e == null)
1228                                 return null;
1229
1230                         type = probe_type;
1231                         eclass = ExprClass.Value;
1232                         Type etype = expr.Type;
1233
1234                         if (TypeManager.IsValueType (probe_type)){
1235                                 Report.Error (77, loc, "The as operator should be used with a reference type only (" +
1236                                               TypeManager.CSharpName (probe_type) + " is a value type)");
1237                                 return null;
1238
1239                         }
1240
1241                         e = Convert.ImplicitConversion (ec, expr, probe_type, loc);
1242                         if (e != null){
1243                                 expr = e;
1244                                 do_isinst = false;
1245                                 return this;
1246                         }
1247
1248                         if (Convert.ExplicitReferenceConversionExists (etype, probe_type)){
1249                                 if (etype.IsGenericParameter)
1250                                         expr = new BoxedCast (expr, etype);
1251
1252                                 do_isinst = true;
1253                                 return this;
1254                         }
1255
1256                         Error_CannotConvertType (etype, probe_type, loc);
1257                         return null;
1258                 }
1259         }
1260
1261         /// <summary>
1262         ///   This represents a typecast in the source language.
1263         ///
1264         ///   FIXME: Cast expressions have an unusual set of parsing
1265         ///   rules, we need to figure those out.
1266         /// </summary>
1267         public class Cast : Expression {
1268                 Expression target_type;
1269                 Expression expr;
1270
1271                 public Cast (Expression cast_type, Expression expr, Location loc)
1272                 {
1273                         this.target_type = cast_type;
1274                         this.expr = expr;
1275                         this.loc = loc;
1276                 }
1277
1278                 public Expression TargetType {
1279                         get {
1280                                 return target_type;
1281                         }
1282                 }
1283
1284                 public Expression Expr {
1285                         get {
1286                                 return expr;
1287                         }
1288                         set {
1289                                 expr = value;
1290                         }
1291                 }
1292
1293                 bool CheckRange (EmitContext ec, long value, Type type, long min, long max)
1294                 {
1295                         if (!ec.ConstantCheckState)
1296                                 return true;
1297
1298                         if ((value < min) || (value > max)) {
1299                                 Error (221, "Constant value `" + value + "' cannot be converted " +
1300                                        "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
1301                                        "syntax to override)");
1302                                 return false;
1303                         }
1304
1305                         return true;
1306                 }
1307
1308                 bool CheckRange (EmitContext ec, ulong value, Type type, ulong max)
1309                 {
1310                         if (!ec.ConstantCheckState)
1311                                 return true;
1312
1313                         if (value > max) {
1314                                 Error (221, "Constant value `" + value + "' cannot be converted " +
1315                                        "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
1316                                        "syntax to override)");
1317                                 return false;
1318                         }
1319
1320                         return true;
1321                 }
1322
1323                 bool CheckUnsigned (EmitContext ec, long value, Type type)
1324                 {
1325                         if (!ec.ConstantCheckState)
1326                                 return true;
1327
1328                         if (value < 0) {
1329                                 Error (221, "Constant value `" + value + "' cannot be converted " +
1330                                        "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
1331                                        "syntax to override)");
1332                                 return false;
1333                         }
1334
1335                         return true;
1336                 }
1337
1338                 /// <summary>
1339                 ///   Attempts to do a compile-time folding of a constant cast.
1340                 /// </summary>
1341                 Expression TryReduce (EmitContext ec, Type target_type)
1342                 {
1343                         Expression real_expr = expr;
1344                         if (real_expr is EnumConstant)
1345                                 real_expr = ((EnumConstant) real_expr).Child;
1346
1347                         if (real_expr is ByteConstant){
1348                                 byte v = ((ByteConstant) real_expr).Value;
1349
1350                                 if (target_type == TypeManager.sbyte_type) {
1351                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1352                                                 return null;
1353                                         return new SByteConstant ((sbyte) v);
1354                                 }
1355                                 if (target_type == TypeManager.short_type)
1356                                         return new ShortConstant ((short) v);
1357                                 if (target_type == TypeManager.ushort_type)
1358                                         return new UShortConstant ((ushort) v);
1359                                 if (target_type == TypeManager.int32_type)
1360                                         return new IntConstant ((int) v);
1361                                 if (target_type == TypeManager.uint32_type)
1362                                         return new UIntConstant ((uint) v);
1363                                 if (target_type == TypeManager.int64_type)
1364                                         return new LongConstant ((long) v);
1365                                 if (target_type == TypeManager.uint64_type)
1366                                         return new ULongConstant ((ulong) v);
1367                                 if (target_type == TypeManager.float_type)
1368                                         return new FloatConstant ((float) v);
1369                                 if (target_type == TypeManager.double_type)
1370                                         return new DoubleConstant ((double) v);
1371                                 if (target_type == TypeManager.char_type)
1372                                         return new CharConstant ((char) v);
1373                                 if (target_type == TypeManager.decimal_type)
1374                                         return new DecimalConstant ((decimal) v);
1375                         }
1376                         if (real_expr is SByteConstant){
1377                                 sbyte v = ((SByteConstant) real_expr).Value;
1378
1379                                 if (target_type == TypeManager.byte_type) {
1380                                         if (!CheckUnsigned (ec, v, target_type))
1381                                                 return null;
1382                                         return new ByteConstant ((byte) v);
1383                                 }
1384                                 if (target_type == TypeManager.short_type)
1385                                         return new ShortConstant ((short) v);
1386                                 if (target_type == TypeManager.ushort_type) {
1387                                         if (!CheckUnsigned (ec, v, target_type))
1388                                                 return null;
1389                                         return new UShortConstant ((ushort) v);
1390                                 } if (target_type == TypeManager.int32_type)
1391                                         return new IntConstant ((int) v);
1392                                 if (target_type == TypeManager.uint32_type) {
1393                                         if (!CheckUnsigned (ec, v, target_type))
1394                                                 return null;
1395                                         return new UIntConstant ((uint) v);
1396                                 } if (target_type == TypeManager.int64_type)
1397                                         return new LongConstant ((long) v);
1398                                 if (target_type == TypeManager.uint64_type) {
1399                                         if (!CheckUnsigned (ec, v, target_type))
1400                                                 return null;
1401                                         return new ULongConstant ((ulong) v);
1402                                 }
1403                                 if (target_type == TypeManager.float_type)
1404                                         return new FloatConstant ((float) v);
1405                                 if (target_type == TypeManager.double_type)
1406                                         return new DoubleConstant ((double) v);
1407                                 if (target_type == TypeManager.char_type) {
1408                                         if (!CheckUnsigned (ec, v, target_type))
1409                                                 return null;
1410                                         return new CharConstant ((char) v);
1411                                 }
1412                                 if (target_type == TypeManager.decimal_type)
1413                                         return new DecimalConstant ((decimal) v);
1414                         }
1415                         if (real_expr is ShortConstant){
1416                                 short v = ((ShortConstant) real_expr).Value;
1417
1418                                 if (target_type == TypeManager.byte_type) {
1419                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1420                                                 return null;
1421                                         return new ByteConstant ((byte) v);
1422                                 }
1423                                 if (target_type == TypeManager.sbyte_type) {
1424                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1425                                                 return null;
1426                                         return new SByteConstant ((sbyte) v);
1427                                 }
1428                                 if (target_type == TypeManager.ushort_type) {
1429                                         if (!CheckUnsigned (ec, v, target_type))
1430                                                 return null;
1431                                         return new UShortConstant ((ushort) v);
1432                                 }
1433                                 if (target_type == TypeManager.int32_type)
1434                                         return new IntConstant ((int) v);
1435                                 if (target_type == TypeManager.uint32_type) {
1436                                         if (!CheckUnsigned (ec, v, target_type))
1437                                                 return null;
1438                                         return new UIntConstant ((uint) v);
1439                                 }
1440                                 if (target_type == TypeManager.int64_type)
1441                                         return new LongConstant ((long) v);
1442                                 if (target_type == TypeManager.uint64_type) {
1443                                         if (!CheckUnsigned (ec, v, target_type))
1444                                                 return null;
1445                                         return new ULongConstant ((ulong) v);
1446                                 }
1447                                 if (target_type == TypeManager.float_type)
1448                                         return new FloatConstant ((float) v);
1449                                 if (target_type == TypeManager.double_type)
1450                                         return new DoubleConstant ((double) v);
1451                                 if (target_type == TypeManager.char_type) {
1452                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1453                                                 return null;
1454                                         return new CharConstant ((char) v);
1455                                 }
1456                                 if (target_type == TypeManager.decimal_type)
1457                                         return new DecimalConstant ((decimal) v);
1458                         }
1459                         if (real_expr is UShortConstant){
1460                                 ushort v = ((UShortConstant) real_expr).Value;
1461
1462                                 if (target_type == TypeManager.byte_type) {
1463                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1464                                                 return null;
1465                                         return new ByteConstant ((byte) v);
1466                                 }
1467                                 if (target_type == TypeManager.sbyte_type) {
1468                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1469                                                 return null;
1470                                         return new SByteConstant ((sbyte) v);
1471                                 }
1472                                 if (target_type == TypeManager.short_type) {
1473                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1474                                                 return null;
1475                                         return new ShortConstant ((short) v);
1476                                 }
1477                                 if (target_type == TypeManager.int32_type)
1478                                         return new IntConstant ((int) v);
1479                                 if (target_type == TypeManager.uint32_type)
1480                                         return new UIntConstant ((uint) v);
1481                                 if (target_type == TypeManager.int64_type)
1482                                         return new LongConstant ((long) v);
1483                                 if (target_type == TypeManager.uint64_type)
1484                                         return new ULongConstant ((ulong) v);
1485                                 if (target_type == TypeManager.float_type)
1486                                         return new FloatConstant ((float) v);
1487                                 if (target_type == TypeManager.double_type)
1488                                         return new DoubleConstant ((double) v);
1489                                 if (target_type == TypeManager.char_type) {
1490                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1491                                                 return null;
1492                                         return new CharConstant ((char) v);
1493                                 }
1494                                 if (target_type == TypeManager.decimal_type)
1495                                         return new DecimalConstant ((decimal) v);
1496                         }
1497                         if (real_expr is IntConstant){
1498                                 int v = ((IntConstant) real_expr).Value;
1499
1500                                 if (target_type == TypeManager.byte_type) {
1501                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1502                                                 return null;
1503                                         return new ByteConstant ((byte) v);
1504                                 }
1505                                 if (target_type == TypeManager.sbyte_type) {
1506                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1507                                                 return null;
1508                                         return new SByteConstant ((sbyte) v);
1509                                 }
1510                                 if (target_type == TypeManager.short_type) {
1511                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1512                                                 return null;
1513                                         return new ShortConstant ((short) v);
1514                                 }
1515                                 if (target_type == TypeManager.ushort_type) {
1516                                         if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
1517                                                 return null;
1518                                         return new UShortConstant ((ushort) v);
1519                                 }
1520                                 if (target_type == TypeManager.uint32_type) {
1521                                         if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
1522                                                 return null;
1523                                         return new UIntConstant ((uint) v);
1524                                 }
1525                                 if (target_type == TypeManager.int64_type)
1526                                         return new LongConstant ((long) v);
1527                                 if (target_type == TypeManager.uint64_type) {
1528                                         if (!CheckUnsigned (ec, v, target_type))
1529                                                 return null;
1530                                         return new ULongConstant ((ulong) v);
1531                                 }
1532                                 if (target_type == TypeManager.float_type)
1533                                         return new FloatConstant ((float) v);
1534                                 if (target_type == TypeManager.double_type)
1535                                         return new DoubleConstant ((double) v);
1536                                 if (target_type == TypeManager.char_type) {
1537                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1538                                                 return null;
1539                                         return new CharConstant ((char) v);
1540                                 }
1541                                 if (target_type == TypeManager.decimal_type)
1542                                         return new DecimalConstant ((decimal) v);
1543                         }
1544                         if (real_expr is UIntConstant){
1545                                 uint v = ((UIntConstant) real_expr).Value;
1546
1547                                 if (target_type == TypeManager.byte_type) {
1548                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1549                                                 return null;
1550                                         return new ByteConstant ((byte) v);
1551                                 }
1552                                 if (target_type == TypeManager.sbyte_type) {
1553                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1554                                                 return null;
1555                                         return new SByteConstant ((sbyte) v);
1556                                 }
1557                                 if (target_type == TypeManager.short_type) {
1558                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1559                                                 return null;
1560                                         return new ShortConstant ((short) v);
1561                                 }
1562                                 if (target_type == TypeManager.ushort_type) {
1563                                         if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
1564                                                 return null;
1565                                         return new UShortConstant ((ushort) v);
1566                                 }
1567                                 if (target_type == TypeManager.int32_type) {
1568                                         if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
1569                                                 return null;
1570                                         return new IntConstant ((int) v);
1571                                 }
1572                                 if (target_type == TypeManager.int64_type)
1573                                         return new LongConstant ((long) v);
1574                                 if (target_type == TypeManager.uint64_type)
1575                                         return new ULongConstant ((ulong) v);
1576                                 if (target_type == TypeManager.float_type)
1577                                         return new FloatConstant ((float) v);
1578                                 if (target_type == TypeManager.double_type)
1579                                         return new DoubleConstant ((double) v);
1580                                 if (target_type == TypeManager.char_type) {
1581                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1582                                                 return null;
1583                                         return new CharConstant ((char) v);
1584                                 }
1585                                 if (target_type == TypeManager.decimal_type)
1586                                         return new DecimalConstant ((decimal) v);
1587                         }
1588                         if (real_expr is LongConstant){
1589                                 long v = ((LongConstant) real_expr).Value;
1590
1591                                 if (target_type == TypeManager.byte_type) {
1592                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1593                                                 return null;
1594                                         return new ByteConstant ((byte) v);
1595                                 }
1596                                 if (target_type == TypeManager.sbyte_type) {
1597                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1598                                                 return null;
1599                                         return new SByteConstant ((sbyte) v);
1600                                 }
1601                                 if (target_type == TypeManager.short_type) {
1602                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1603                                                 return null;
1604                                         return new ShortConstant ((short) v);
1605                                 }
1606                                 if (target_type == TypeManager.ushort_type) {
1607                                         if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
1608                                                 return null;
1609                                         return new UShortConstant ((ushort) v);
1610                                 }
1611                                 if (target_type == TypeManager.int32_type) {
1612                                         if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
1613                                                 return null;
1614                                         return new IntConstant ((int) v);
1615                                 }
1616                                 if (target_type == TypeManager.uint32_type) {
1617                                         if (!CheckRange (ec, v, target_type, UInt32.MinValue, UInt32.MaxValue))
1618                                                 return null;
1619                                         return new UIntConstant ((uint) v);
1620                                 }
1621                                 if (target_type == TypeManager.uint64_type) {
1622                                         if (!CheckUnsigned (ec, v, target_type))
1623                                                 return null;
1624                                         return new ULongConstant ((ulong) v);
1625                                 }
1626                                 if (target_type == TypeManager.float_type)
1627                                         return new FloatConstant ((float) v);
1628                                 if (target_type == TypeManager.double_type)
1629                                         return new DoubleConstant ((double) v);
1630                                 if (target_type == TypeManager.char_type) {
1631                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1632                                                 return null;
1633                                         return new CharConstant ((char) v);
1634                                 }
1635                                 if (target_type == TypeManager.decimal_type)
1636                                         return new DecimalConstant ((decimal) v);
1637                         }
1638                         if (real_expr is ULongConstant){
1639                                 ulong v = ((ULongConstant) real_expr).Value;
1640
1641                                 if (target_type == TypeManager.byte_type) {
1642                                         if (!CheckRange (ec, v, target_type, Byte.MaxValue))
1643                                                 return null;
1644                                         return new ByteConstant ((byte) v);
1645                                 }
1646                                 if (target_type == TypeManager.sbyte_type) {
1647                                         if (!CheckRange (ec, v, target_type, (ulong) SByte.MaxValue))
1648                                                 return null;
1649                                         return new SByteConstant ((sbyte) v);
1650                                 }
1651                                 if (target_type == TypeManager.short_type) {
1652                                         if (!CheckRange (ec, v, target_type, (ulong) Int16.MaxValue))
1653                                                 return null;
1654                                         return new ShortConstant ((short) v);
1655                                 }
1656                                 if (target_type == TypeManager.ushort_type) {
1657                                         if (!CheckRange (ec, v, target_type, UInt16.MaxValue))
1658                                                 return null;
1659                                         return new UShortConstant ((ushort) v);
1660                                 }
1661                                 if (target_type == TypeManager.int32_type) {
1662                                         if (!CheckRange (ec, v, target_type, Int32.MaxValue))
1663                                                 return null;
1664                                         return new IntConstant ((int) v);
1665                                 }
1666                                 if (target_type == TypeManager.uint32_type) {
1667                                         if (!CheckRange (ec, v, target_type, UInt32.MaxValue))
1668                                                 return null;
1669                                         return new UIntConstant ((uint) v);
1670                                 }
1671                                 if (target_type == TypeManager.int64_type) {
1672                                         if (!CheckRange (ec, v, target_type, (ulong) Int64.MaxValue))
1673                                                 return null;
1674                                         return new LongConstant ((long) v);
1675                                 }
1676                                 if (target_type == TypeManager.float_type)
1677                                         return new FloatConstant ((float) v);
1678                                 if (target_type == TypeManager.double_type)
1679                                         return new DoubleConstant ((double) v);
1680                                 if (target_type == TypeManager.char_type) {
1681                                         if (!CheckRange (ec, v, target_type, Char.MaxValue))
1682                                                 return null;
1683                                         return new CharConstant ((char) v);
1684                                 }
1685                                 if (target_type == TypeManager.decimal_type)
1686                                         return new DecimalConstant ((decimal) v);
1687                         }
1688                         if (real_expr is FloatConstant){
1689                                 float v = ((FloatConstant) real_expr).Value;
1690
1691                                 if (target_type == TypeManager.byte_type)
1692                                         return new ByteConstant ((byte) v);
1693                                 if (target_type == TypeManager.sbyte_type)
1694                                         return new SByteConstant ((sbyte) v);
1695                                 if (target_type == TypeManager.short_type)
1696                                         return new ShortConstant ((short) v);
1697                                 if (target_type == TypeManager.ushort_type)
1698                                         return new UShortConstant ((ushort) v);
1699                                 if (target_type == TypeManager.int32_type)
1700                                         return new IntConstant ((int) v);
1701                                 if (target_type == TypeManager.uint32_type)
1702                                         return new UIntConstant ((uint) v);
1703                                 if (target_type == TypeManager.int64_type)
1704                                         return new LongConstant ((long) v);
1705                                 if (target_type == TypeManager.uint64_type)
1706                                         return new ULongConstant ((ulong) v);
1707                                 if (target_type == TypeManager.double_type)
1708                                         return new DoubleConstant ((double) v);
1709                                 if (target_type == TypeManager.char_type)
1710                                         return new CharConstant ((char) v);
1711                                 if (target_type == TypeManager.decimal_type)
1712                                         return new DecimalConstant ((decimal) v);
1713                         }
1714                         if (real_expr is DoubleConstant){
1715                                 double v = ((DoubleConstant) real_expr).Value;
1716
1717                                 if (target_type == TypeManager.byte_type){
1718                                         return new ByteConstant ((byte) v);
1719                                 } if (target_type == TypeManager.sbyte_type)
1720                                         return new SByteConstant ((sbyte) v);
1721                                 if (target_type == TypeManager.short_type)
1722                                         return new ShortConstant ((short) v);
1723                                 if (target_type == TypeManager.ushort_type)
1724                                         return new UShortConstant ((ushort) v);
1725                                 if (target_type == TypeManager.int32_type)
1726                                         return new IntConstant ((int) v);
1727                                 if (target_type == TypeManager.uint32_type)
1728                                         return new UIntConstant ((uint) v);
1729                                 if (target_type == TypeManager.int64_type)
1730                                         return new LongConstant ((long) v);
1731                                 if (target_type == TypeManager.uint64_type)
1732                                         return new ULongConstant ((ulong) v);
1733                                 if (target_type == TypeManager.float_type)
1734                                         return new FloatConstant ((float) v);
1735                                 if (target_type == TypeManager.char_type)
1736                                         return new CharConstant ((char) v);
1737                                 if (target_type == TypeManager.decimal_type)
1738                                         return new DecimalConstant ((decimal) v);
1739                         }
1740
1741                         if (real_expr is CharConstant){
1742                                 char v = ((CharConstant) real_expr).Value;
1743
1744                                 if (target_type == TypeManager.byte_type) {
1745                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1746                                                 return null;
1747                                         return new ByteConstant ((byte) v);
1748                                 }
1749                                 if (target_type == TypeManager.sbyte_type) {
1750                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1751                                                 return null;
1752                                         return new SByteConstant ((sbyte) v);
1753                                 }
1754                                 if (target_type == TypeManager.short_type) {
1755                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1756                                                 return null;
1757                                         return new ShortConstant ((short) v);
1758                                 }
1759                                 if (target_type == TypeManager.int32_type)
1760                                         return new IntConstant ((int) v);
1761                                 if (target_type == TypeManager.uint32_type)
1762                                         return new UIntConstant ((uint) v);
1763                                 if (target_type == TypeManager.int64_type)
1764                                         return new LongConstant ((long) v);
1765                                 if (target_type == TypeManager.uint64_type)
1766                                         return new ULongConstant ((ulong) v);
1767                                 if (target_type == TypeManager.float_type)
1768                                         return new FloatConstant ((float) v);
1769                                 if (target_type == TypeManager.double_type)
1770                                         return new DoubleConstant ((double) v);
1771                                 if (target_type == TypeManager.char_type) {
1772                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1773                                                 return null;
1774                                         return new CharConstant ((char) v);
1775                                 }
1776                                 if (target_type == TypeManager.decimal_type)
1777                                         return new DecimalConstant ((decimal) v);
1778                         }
1779
1780                         return null;
1781                 }
1782
1783                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1784                 {
1785                         expr = expr.DoResolveLValue (ec, right_side);
1786                         if (expr == null)
1787                                 return null;
1788
1789                         return ResolveRest (ec);
1790                 }
1791
1792                 public override Expression DoResolve (EmitContext ec)
1793                 {
1794                         expr = expr.Resolve (ec);
1795                         if (expr == null)
1796                                 return null;
1797
1798                         return ResolveRest (ec);
1799                 }
1800
1801                 Expression ResolveRest (EmitContext ec)
1802                 {
1803                         TypeExpr target = target_type.ResolveAsTypeTerminal (ec);
1804                         if (target == null)
1805                                 return null;
1806
1807                         type = target.Type;
1808
1809                         CheckObsoleteAttribute (type);
1810
1811                         if (type.IsAbstract && type.IsSealed) {
1812                                 Report.Error (716, loc, "Cannot convert to static type '{0}'", TypeManager.CSharpName (type));
1813                                 return null;
1814                         }
1815
1816                         eclass = ExprClass.Value;
1817
1818                         if (expr is Constant){
1819                                 Expression e = TryReduce (ec, type);
1820
1821                                 if (e != null)
1822                                         return e;
1823                         }
1824
1825                         if (type.IsPointer && !ec.InUnsafe) {
1826                                 UnsafeError (loc);
1827                                 return null;
1828                         }
1829                         expr = Convert.ExplicitConversion (ec, expr, type, loc);
1830                         return expr;
1831                 }
1832
1833                 public override void Emit (EmitContext ec)
1834                 {
1835                         //
1836                         // This one will never happen
1837                         //
1838                         throw new Exception ("Should not happen");
1839                 }
1840         }
1841
1842         /// <summary>
1843         ///   Binary operators
1844         /// </summary>
1845         public class Binary : Expression {
1846                 public enum Operator : byte {
1847                         Multiply, Division, Modulus,
1848                         Addition, Subtraction,
1849                         LeftShift, RightShift,
1850                         LessThan, GreaterThan, LessThanOrEqual, GreaterThanOrEqual,
1851                         Equality, Inequality,
1852                         BitwiseAnd,
1853                         ExclusiveOr,
1854                         BitwiseOr,
1855                         LogicalAnd,
1856                         LogicalOr,
1857                         TOP
1858                 }
1859
1860                 Operator oper;
1861                 Expression left, right;
1862
1863                 // This must be kept in sync with Operator!!!
1864                 public static readonly string [] oper_names;
1865
1866                 static Binary ()
1867                 {
1868                         oper_names = new string [(int) Operator.TOP];
1869
1870                         oper_names [(int) Operator.Multiply] = "op_Multiply";
1871                         oper_names [(int) Operator.Division] = "op_Division";
1872                         oper_names [(int) Operator.Modulus] = "op_Modulus";
1873                         oper_names [(int) Operator.Addition] = "op_Addition";
1874                         oper_names [(int) Operator.Subtraction] = "op_Subtraction";
1875                         oper_names [(int) Operator.LeftShift] = "op_LeftShift";
1876                         oper_names [(int) Operator.RightShift] = "op_RightShift";
1877                         oper_names [(int) Operator.LessThan] = "op_LessThan";
1878                         oper_names [(int) Operator.GreaterThan] = "op_GreaterThan";
1879                         oper_names [(int) Operator.LessThanOrEqual] = "op_LessThanOrEqual";
1880                         oper_names [(int) Operator.GreaterThanOrEqual] = "op_GreaterThanOrEqual";
1881                         oper_names [(int) Operator.Equality] = "op_Equality";
1882                         oper_names [(int) Operator.Inequality] = "op_Inequality";
1883                         oper_names [(int) Operator.BitwiseAnd] = "op_BitwiseAnd";
1884                         oper_names [(int) Operator.BitwiseOr] = "op_BitwiseOr";
1885                         oper_names [(int) Operator.ExclusiveOr] = "op_ExclusiveOr";
1886                         oper_names [(int) Operator.LogicalOr] = "op_LogicalOr";
1887                         oper_names [(int) Operator.LogicalAnd] = "op_LogicalAnd";
1888                 }
1889
1890                 public Binary (Operator oper, Expression left, Expression right, Location loc)
1891                 {
1892                         this.oper = oper;
1893                         this.left = left;
1894                         this.right = right;
1895                         this.loc = loc;
1896                 }
1897
1898                 public Operator Oper {
1899                         get {
1900                                 return oper;
1901                         }
1902                         set {
1903                                 oper = value;
1904                         }
1905                 }
1906
1907                 public Expression Left {
1908                         get {
1909                                 return left;
1910                         }
1911                         set {
1912                                 left = value;
1913                         }
1914                 }
1915
1916                 public Expression Right {
1917                         get {
1918                                 return right;
1919                         }
1920                         set {
1921                                 right = value;
1922                         }
1923                 }
1924
1925
1926                 /// <summary>
1927                 ///   Returns a stringified representation of the Operator
1928                 /// </summary>
1929                 static string OperName (Operator oper)
1930                 {
1931                         switch (oper){
1932                         case Operator.Multiply:
1933                                 return "*";
1934                         case Operator.Division:
1935                                 return "/";
1936                         case Operator.Modulus:
1937                                 return "%";
1938                         case Operator.Addition:
1939                                 return "+";
1940                         case Operator.Subtraction:
1941                                 return "-";
1942                         case Operator.LeftShift:
1943                                 return "<<";
1944                         case Operator.RightShift:
1945                                 return ">>";
1946                         case Operator.LessThan:
1947                                 return "<";
1948                         case Operator.GreaterThan:
1949                                 return ">";
1950                         case Operator.LessThanOrEqual:
1951                                 return "<=";
1952                         case Operator.GreaterThanOrEqual:
1953                                 return ">=";
1954                         case Operator.Equality:
1955                                 return "==";
1956                         case Operator.Inequality:
1957                                 return "!=";
1958                         case Operator.BitwiseAnd:
1959                                 return "&";
1960                         case Operator.BitwiseOr:
1961                                 return "|";
1962                         case Operator.ExclusiveOr:
1963                                 return "^";
1964                         case Operator.LogicalOr:
1965                                 return "||";
1966                         case Operator.LogicalAnd:
1967                                 return "&&";
1968                         }
1969
1970                         return oper.ToString ();
1971                 }
1972
1973                 public override string ToString ()
1974                 {
1975                         return "operator " + OperName (oper) + "(" + left.ToString () + ", " +
1976                                 right.ToString () + ")";
1977                 }
1978
1979                 Expression ForceConversion (EmitContext ec, Expression expr, Type target_type)
1980                 {
1981                         if (expr.Type == target_type)
1982                                 return expr;
1983
1984                         return Convert.ImplicitConversion (ec, expr, target_type, loc);
1985                 }
1986
1987                 public static void Error_OperatorAmbiguous (Location loc, Operator oper, Type l, Type r)
1988                 {
1989                         Report.Error (
1990                                 34, loc, "Operator `" + OperName (oper)
1991                                 + "' is ambiguous on operands of type `"
1992                                 + TypeManager.CSharpName (l) + "' "
1993                                 + "and `" + TypeManager.CSharpName (r)
1994                                 + "'");
1995                 }
1996
1997                 bool IsOfType (EmitContext ec, Type l, Type r, Type t, bool check_user_conversions)
1998                 {
1999                         if ((l == t) || (r == t))
2000                                 return true;
2001
2002                         if (!check_user_conversions)
2003                                 return false;
2004
2005                         if (Convert.ImplicitUserConversionExists (ec, l, t))
2006                                 return true;
2007                         else if (Convert.ImplicitUserConversionExists (ec, r, t))
2008                                 return true;
2009                         else
2010                                 return false;
2011                 }
2012
2013                 //
2014                 // Note that handling the case l == Decimal || r == Decimal
2015                 // is taken care of by the Step 1 Operator Overload resolution.
2016                 //
2017                 // If `check_user_conv' is true, we also check whether a user-defined conversion
2018                 // exists.  Note that we only need to do this if both arguments are of a user-defined
2019                 // type, otherwise ConvertImplict() already finds the user-defined conversion for us,
2020                 // so we don't explicitly check for performance reasons.
2021                 //
2022                 bool DoNumericPromotions (EmitContext ec, Type l, Type r, bool check_user_conv)
2023                 {
2024                         if (IsOfType (ec, l, r, TypeManager.double_type, check_user_conv)){
2025                                 //
2026                                 // If either operand is of type double, the other operand is
2027                                 // conveted to type double.
2028                                 //
2029                                 if (r != TypeManager.double_type)
2030                                         right = Convert.ImplicitConversion (ec, right, TypeManager.double_type, loc);
2031                                 if (l != TypeManager.double_type)
2032                                         left = Convert.ImplicitConversion (ec, left, TypeManager.double_type, loc);
2033
2034                                 type = TypeManager.double_type;
2035                         } else if (IsOfType (ec, l, r, TypeManager.float_type, check_user_conv)){
2036                                 //
2037                                 // if either operand is of type float, the other operand is
2038                                 // converted to type float.
2039                                 //
2040                                 if (r != TypeManager.double_type)
2041                                         right = Convert.ImplicitConversion (ec, right, TypeManager.float_type, loc);
2042                                 if (l != TypeManager.double_type)
2043                                         left = Convert.ImplicitConversion (ec, left, TypeManager.float_type, loc);
2044                                 type = TypeManager.float_type;
2045                         } else if (IsOfType (ec, l, r, TypeManager.uint64_type, check_user_conv)){
2046                                 Expression e;
2047                                 Type other;
2048                                 //
2049                                 // If either operand is of type ulong, the other operand is
2050                                 // converted to type ulong.  or an error ocurrs if the other
2051                                 // operand is of type sbyte, short, int or long
2052                                 //
2053                                 if (l == TypeManager.uint64_type){
2054                                         if (r != TypeManager.uint64_type){
2055                                                 if (right is IntConstant){
2056                                                         IntConstant ic = (IntConstant) right;
2057
2058                                                         e = Convert.TryImplicitIntConversion (l, ic);
2059                                                         if (e != null)
2060                                                                 right = e;
2061                                                 } else if (right is LongConstant){
2062                                                         long ll = ((LongConstant) right).Value;
2063
2064                                                         if (ll >= 0)
2065                                                                 right = new ULongConstant ((ulong) ll);
2066                                                 } else {
2067                                                         e = Convert.ImplicitNumericConversion (ec, right, l, loc);
2068                                                         if (e != null)
2069                                                                 right = e;
2070                                                 }
2071                                         }
2072                                         other = right.Type;
2073                                 } else {
2074                                         if (left is IntConstant){
2075                                                 e = Convert.TryImplicitIntConversion (r, (IntConstant) left);
2076                                                 if (e != null)
2077                                                         left = e;
2078                                         } else if (left is LongConstant){
2079                                                 long ll = ((LongConstant) left).Value;
2080
2081                                                 if (ll > 0)
2082                                                         left = new ULongConstant ((ulong) ll);
2083                                         } else {
2084                                                 e = Convert.ImplicitNumericConversion (ec, left, r, loc);
2085                                                 if (e != null)
2086                                                         left = e;
2087                                         }
2088                                         other = left.Type;
2089                                 }
2090
2091                                 if ((other == TypeManager.sbyte_type) ||
2092                                     (other == TypeManager.short_type) ||
2093                                     (other == TypeManager.int32_type) ||
2094                                     (other == TypeManager.int64_type))
2095                                         Error_OperatorAmbiguous (loc, oper, l, r);
2096                                 else {
2097                                         left = ForceConversion (ec, left, TypeManager.uint64_type);
2098                                         right = ForceConversion (ec, right, TypeManager.uint64_type);
2099                                 }
2100                                 type = TypeManager.uint64_type;
2101                         } else if (IsOfType (ec, l, r, TypeManager.int64_type, check_user_conv)){
2102                                 //
2103                                 // If either operand is of type long, the other operand is converted
2104                                 // to type long.
2105                                 //
2106                                 if (l != TypeManager.int64_type)
2107                                         left = Convert.ImplicitConversion (ec, left, TypeManager.int64_type, loc);
2108                                 if (r != TypeManager.int64_type)
2109                                         right = Convert.ImplicitConversion (ec, right, TypeManager.int64_type, loc);
2110
2111                                 type = TypeManager.int64_type;
2112                         } else if (IsOfType (ec, l, r, TypeManager.uint32_type, check_user_conv)){
2113                                 //
2114                                 // If either operand is of type uint, and the other
2115                                 // operand is of type sbyte, short or int, othe operands are
2116                                 // converted to type long (unless we have an int constant).
2117                                 //
2118                                 Type other = null;
2119
2120                                 if (l == TypeManager.uint32_type){
2121                                         if (right is IntConstant){
2122                                                 IntConstant ic = (IntConstant) right;
2123                                                 int val = ic.Value;
2124
2125                                                 if (val >= 0){
2126                                                         right = new UIntConstant ((uint) val);
2127                                                         type = l;
2128
2129                                                         return true;
2130                                                 }
2131                                         }
2132                                         other = r;
2133                                 } else if (r == TypeManager.uint32_type){
2134                                         if (left is IntConstant){
2135                                                 IntConstant ic = (IntConstant) left;
2136                                                 int val = ic.Value;
2137
2138                                                 if (val >= 0){
2139                                                         left = new UIntConstant ((uint) val);
2140                                                         type = r;
2141                                                         return true;
2142                                                 }
2143                                         }
2144
2145                                         other = l;
2146                                 }
2147
2148                                 if ((other == TypeManager.sbyte_type) ||
2149                                     (other == TypeManager.short_type) ||
2150                                     (other == TypeManager.int32_type)){
2151                                         left = ForceConversion (ec, left, TypeManager.int64_type);
2152                                         right = ForceConversion (ec, right, TypeManager.int64_type);
2153                                         type = TypeManager.int64_type;
2154                                 } else {
2155                                         //
2156                                         // if either operand is of type uint, the other
2157                                         // operand is converd to type uint
2158                                         //
2159                                         left = ForceConversion (ec, left, TypeManager.uint32_type);
2160                                         right = ForceConversion (ec, right, TypeManager.uint32_type);
2161                                         type = TypeManager.uint32_type;
2162                                 }
2163                         } else if (l == TypeManager.decimal_type || r == TypeManager.decimal_type){
2164                                 if (l != TypeManager.decimal_type)
2165                                         left = Convert.ImplicitConversion (ec, left, TypeManager.decimal_type, loc);
2166
2167                                 if (r != TypeManager.decimal_type)
2168                                         right = Convert.ImplicitConversion (ec, right, TypeManager.decimal_type, loc);
2169                                 type = TypeManager.decimal_type;
2170                         } else {
2171                                 left = ForceConversion (ec, left, TypeManager.int32_type);
2172                                 right = ForceConversion (ec, right, TypeManager.int32_type);
2173
2174                                 type = TypeManager.int32_type;
2175                         }
2176
2177                         return (left != null) && (right != null);
2178                 }
2179
2180                 static public void Error_OperatorCannotBeApplied (Location loc, string name, Type l, Type r)
2181                 {
2182                         Report.Error (19, loc,
2183                                "Operator " + name + " cannot be applied to operands of type `" +
2184                                TypeManager.CSharpName (l) + "' and `" +
2185                                TypeManager.CSharpName (r) + "'");
2186                 }
2187
2188                 void Error_OperatorCannotBeApplied ()
2189                 {
2190                         Error_OperatorCannotBeApplied (loc, OperName (oper), left.Type, right.Type);
2191                 }
2192
2193                 static bool is_unsigned (Type t)
2194                 {
2195                         return (t == TypeManager.uint32_type || t == TypeManager.uint64_type ||
2196                                 t == TypeManager.short_type || t == TypeManager.byte_type);
2197                 }
2198
2199                 static bool is_user_defined (Type t)
2200                 {
2201                         if (t.IsSubclassOf (TypeManager.value_type) &&
2202                             (!TypeManager.IsBuiltinType (t) || t == TypeManager.decimal_type))
2203                                 return true;
2204                         else
2205                                 return false;
2206                 }
2207
2208                 Expression Make32or64 (EmitContext ec, Expression e)
2209                 {
2210                         Type t= e.Type;
2211
2212                         if (t == TypeManager.int32_type || t == TypeManager.uint32_type ||
2213                             t == TypeManager.int64_type || t == TypeManager.uint64_type)
2214                                 return e;
2215                         Expression ee = Convert.ImplicitConversion (ec, e, TypeManager.int32_type, loc);
2216                         if (ee != null)
2217                                 return ee;
2218                         ee = Convert.ImplicitConversion (ec, e, TypeManager.uint32_type, loc);
2219                         if (ee != null)
2220                                 return ee;
2221                         ee = Convert.ImplicitConversion (ec, e, TypeManager.int64_type, loc);
2222                         if (ee != null)
2223                                 return ee;
2224                         ee = Convert.ImplicitConversion (ec, e, TypeManager.uint64_type, loc);
2225                         if (ee != null)
2226                                 return ee;
2227                         return null;
2228                 }
2229
2230                 Expression CheckShiftArguments (EmitContext ec)
2231                 {
2232                         Expression e;
2233
2234                         e = ForceConversion (ec, right, TypeManager.int32_type);
2235                         if (e == null){
2236                                 Error_OperatorCannotBeApplied ();
2237                                 return null;
2238                         }
2239                         right = e;
2240
2241                         if (((e = Convert.ImplicitConversion (ec, left, TypeManager.int32_type, loc)) != null) ||
2242                             ((e = Convert.ImplicitConversion (ec, left, TypeManager.uint32_type, loc)) != null) ||
2243                             ((e = Convert.ImplicitConversion (ec, left, TypeManager.int64_type, loc)) != null) ||
2244                             ((e = Convert.ImplicitConversion (ec, left, TypeManager.uint64_type, loc)) != null)){
2245                                 left = e;
2246                                 type = e.Type;
2247
2248                                 if (type == TypeManager.int32_type || type == TypeManager.uint32_type){
2249                                         right = new Binary (Binary.Operator.BitwiseAnd, right, new IntLiteral (31), loc);
2250                                         right = right.DoResolve (ec);
2251                                 } else {
2252                                         right = new Binary (Binary.Operator.BitwiseAnd, right, new IntLiteral (63), loc);
2253                                         right = right.DoResolve (ec);
2254                                 }
2255
2256                                 return this;
2257                         }
2258                         Error_OperatorCannotBeApplied ();
2259                         return null;
2260                 }
2261
2262                 //
2263                 // This is used to check if a test 'x == null' can be optimized to a reference equals,
2264                 // i.e., not invoke op_Equality.
2265                 //
2266                 static bool EqualsNullIsReferenceEquals (Type t)
2267                 {
2268                         return t == TypeManager.object_type || t == TypeManager.string_type ||
2269                                 t == TypeManager.delegate_type || t.IsSubclassOf (TypeManager.delegate_type);
2270                 }
2271
2272                 Expression ResolveOperator (EmitContext ec)
2273                 {
2274                         Type l = left.Type;
2275                         Type r = right.Type;
2276
2277                         if (oper == Operator.Equality || oper == Operator.Inequality){
2278                                 if (l.IsGenericParameter && (right is NullLiteral)) {
2279                                         if (l.BaseType == TypeManager.value_type) {
2280                                                 Error_OperatorCannotBeApplied ();
2281                                                 return null;
2282                                         }
2283
2284                                         left = new BoxedCast (left);
2285                                         Type = TypeManager.bool_type;
2286                                         return this;
2287                                 }
2288
2289                                 if (r.IsGenericParameter && (left is NullLiteral)) {
2290                                         if (r.BaseType == TypeManager.value_type) {
2291                                                 Error_OperatorCannotBeApplied ();
2292                                                 return null;
2293                                         }
2294
2295                                         right = new BoxedCast (right);
2296                                         Type = TypeManager.bool_type;
2297                                         return this;
2298                                 }
2299
2300                                 //
2301                                 // Optimize out call to op_Equality in a few cases.
2302                                 //
2303                                 if ((l == TypeManager.null_type && EqualsNullIsReferenceEquals (r)) ||
2304                                     (r == TypeManager.null_type && EqualsNullIsReferenceEquals (l))) {
2305                                         Type = TypeManager.bool_type;
2306
2307                                         return this;
2308                                 }
2309
2310                                 // IntPtr equality
2311                                 if (l == TypeManager.intptr_type && r == TypeManager.intptr_type) {
2312                                         Type = TypeManager.bool_type;
2313
2314                                         return this;
2315                                 }
2316                         }
2317
2318                         //
2319                         // Do not perform operator overload resolution when both sides are
2320                         // built-in types
2321                         //
2322                         if (!(TypeManager.IsPrimitiveType (l) && TypeManager.IsPrimitiveType (r))){
2323                                 //
2324                                 // Step 1: Perform Operator Overload location
2325                                 //
2326                                 Expression left_expr, right_expr;
2327
2328                                 string op = oper_names [(int) oper];
2329
2330                                 MethodGroupExpr union;
2331                                 left_expr = MemberLookup (ec, l, op, MemberTypes.Method, AllBindingFlags, loc);
2332                                 if (r != l){
2333                                         right_expr = MemberLookup (
2334                                                 ec, r, op, MemberTypes.Method, AllBindingFlags, loc);
2335                                         union = Invocation.MakeUnionSet (left_expr, right_expr, loc);
2336                                 } else
2337                                         union = (MethodGroupExpr) left_expr;
2338
2339                                 if (union != null) {
2340                                         ArrayList args = new ArrayList (2);
2341                                         args.Add (new Argument (left, Argument.AType.Expression));
2342                                         args.Add (new Argument (right, Argument.AType.Expression));
2343
2344                                         MethodBase method = Invocation.OverloadResolve (
2345                                                 ec, union, args, true, Location.Null);
2346
2347                                         if (method != null) {
2348                                                 MethodInfo mi = (MethodInfo) method;
2349
2350                                                 return new BinaryMethod (mi.ReturnType, method, args);
2351                                         }
2352                                 }
2353                         }
2354
2355                         //
2356                         // Step 0: String concatenation (because overloading will get this wrong)
2357                         //
2358                         if (oper == Operator.Addition){
2359                                 //
2360                                 // If any of the arguments is a string, cast to string
2361                                 //
2362
2363                                 // Simple constant folding
2364                                 if (left is StringConstant && right is StringConstant)
2365                                         return new StringConstant (((StringConstant) left).Value + ((StringConstant) right).Value);
2366
2367                                 if (l == TypeManager.string_type || r == TypeManager.string_type) {
2368
2369                                         if (r == TypeManager.void_type || l == TypeManager.void_type) {
2370                                                 Error_OperatorCannotBeApplied ();
2371                                                 return null;
2372                                         }
2373
2374                                         // try to fold it in on the left
2375                                         if (left is StringConcat) {
2376
2377                                                 //
2378                                                 // We have to test here for not-null, since we can be doubly-resolved
2379                                                 // take care of not appending twice
2380                                                 //
2381                                                 if (type == null){
2382                                                         type = TypeManager.string_type;
2383                                                         ((StringConcat) left).Append (ec, right);
2384                                                         return left.Resolve (ec);
2385                                                 } else {
2386                                                         return left;
2387                                                 }
2388                                         }
2389
2390                                         // Otherwise, start a new concat expression
2391                                         return new StringConcat (ec, loc, left, right).Resolve (ec);
2392                                 }
2393
2394                                 //
2395                                 // Transform a + ( - b) into a - b
2396                                 //
2397                                 if (right is Unary){
2398                                         Unary right_unary = (Unary) right;
2399
2400                                         if (right_unary.Oper == Unary.Operator.UnaryNegation){
2401                                                 oper = Operator.Subtraction;
2402                                                 right = right_unary.Expr;
2403                                                 r = right.Type;
2404                                         }
2405                                 }
2406                         }
2407
2408                         if (oper == Operator.Equality || oper == Operator.Inequality){
2409                                 if (l == TypeManager.bool_type || r == TypeManager.bool_type){
2410                                         if (r != TypeManager.bool_type || l != TypeManager.bool_type){
2411                                                 Error_OperatorCannotBeApplied ();
2412                                                 return null;
2413                                         }
2414
2415                                         type = TypeManager.bool_type;
2416                                         return this;
2417                                 }
2418
2419                                 if (l.IsPointer || r.IsPointer) {
2420                                         if (l.IsPointer && r.IsPointer) {
2421                                                 type = TypeManager.bool_type;
2422                                                 return this;
2423                                         }
2424
2425                                         if (l.IsPointer && r == TypeManager.null_type) {
2426                                                 right = new EmptyCast (NullPointer.Null, l);
2427                                                 type = TypeManager.bool_type;
2428                                                 return this;
2429                                         }
2430
2431                                         if (r.IsPointer && l == TypeManager.null_type) {
2432                                                 left = new EmptyCast (NullPointer.Null, r);
2433                                                 type = TypeManager.bool_type;
2434                                                 return this;
2435                                         }
2436                                 }
2437
2438                                 //
2439                                 // operator != (object a, object b)
2440                                 // operator == (object a, object b)
2441                                 //
2442                                 // For this to be used, both arguments have to be reference-types.
2443                                 // Read the rationale on the spec (14.9.6)
2444                                 //
2445                                 // Also, if at compile time we know that the classes do not inherit
2446                                 // one from the other, then we catch the error there.
2447                                 //
2448                                 if (!(l.IsValueType || r.IsValueType)){
2449                                         type = TypeManager.bool_type;
2450
2451                                         if (l == r)
2452                                                 return this;
2453
2454                                         if (l.IsSubclassOf (r) || r.IsSubclassOf (l))
2455                                                 return this;
2456
2457                                         //
2458                                         // Also, a standard conversion must exist from either one
2459                                         //
2460                                         if (!(Convert.ImplicitStandardConversionExists (ec, left, r) ||
2461                                               Convert.ImplicitStandardConversionExists (ec, right, l))){
2462                                                 Error_OperatorCannotBeApplied ();
2463                                                 return null;
2464                                         }
2465                                         //
2466                                         // We are going to have to convert to an object to compare
2467                                         //
2468                                         if (l != TypeManager.object_type)
2469                                                 left = new EmptyCast (left, TypeManager.object_type);
2470                                         if (r != TypeManager.object_type)
2471                                                 right = new EmptyCast (right, TypeManager.object_type);
2472
2473                                         //
2474                                         // FIXME: CSC here catches errors cs254 and cs252
2475                                         //
2476                                         return this;
2477                                 }
2478
2479                                 //
2480                                 // One of them is a valuetype, but the other one is not.
2481                                 //
2482                                 if (!l.IsValueType || !r.IsValueType) {
2483                                         Error_OperatorCannotBeApplied ();
2484                                         return null;
2485                                 }
2486                         }
2487
2488                         // Only perform numeric promotions on:
2489                         // +, -, *, /, %, &, |, ^, ==, !=, <, >, <=, >=
2490                         //
2491                         if (oper == Operator.Addition || oper == Operator.Subtraction) {
2492                                 if (TypeManager.IsDelegateType (l)){
2493                                         if (((right.eclass == ExprClass.MethodGroup) ||
2494                                              (r == TypeManager.anonymous_method_type))){
2495                                                 if ((RootContext.Version != LanguageVersion.ISO_1)){
2496                                                         Expression tmp = Convert.ImplicitConversionRequired (ec, right, l, loc);
2497                                                         if (tmp == null)
2498                                                                 return null;
2499                                                         right = tmp;
2500                                                         r = right.Type;
2501                                                 }
2502                                         }
2503
2504                                         if (TypeManager.IsDelegateType (r)){
2505                                                 MethodInfo method;
2506                                                 ArrayList args = new ArrayList (2);
2507
2508                                                 args = new ArrayList (2);
2509                                                 args.Add (new Argument (left, Argument.AType.Expression));
2510                                                 args.Add (new Argument (right, Argument.AType.Expression));
2511
2512                                                 if (oper == Operator.Addition)
2513                                                         method = TypeManager.delegate_combine_delegate_delegate;
2514                                                 else
2515                                                         method = TypeManager.delegate_remove_delegate_delegate;
2516
2517                                                 if (!TypeManager.IsEqual (l, r)) {
2518                                                         Error_OperatorCannotBeApplied ();
2519                                                         return null;
2520                                                 }
2521
2522                                                 return new BinaryDelegate (l, method, args);
2523                                         }
2524                                 }
2525
2526                                 //
2527                                 // Pointer arithmetic:
2528                                 //
2529                                 // T* operator + (T* x, int y);
2530                                 // T* operator + (T* x, uint y);
2531                                 // T* operator + (T* x, long y);
2532                                 // T* operator + (T* x, ulong y);
2533                                 //
2534                                 // T* operator + (int y,   T* x);
2535                                 // T* operator + (uint y,  T *x);
2536                                 // T* operator + (long y,  T *x);
2537                                 // T* operator + (ulong y, T *x);
2538                                 //
2539                                 // T* operator - (T* x, int y);
2540                                 // T* operator - (T* x, uint y);
2541                                 // T* operator - (T* x, long y);
2542                                 // T* operator - (T* x, ulong y);
2543                                 //
2544                                 // long operator - (T* x, T *y)
2545                                 //
2546                                 if (l.IsPointer){
2547                                         if (r.IsPointer && oper == Operator.Subtraction){
2548                                                 if (r == l)
2549                                                         return new PointerArithmetic (
2550                                                                 false, left, right, TypeManager.int64_type,
2551                                                                 loc).Resolve (ec);
2552                                         } else {
2553                                                 Expression t = Make32or64 (ec, right);
2554                                                 if (t != null)
2555                                                         return new PointerArithmetic (oper == Operator.Addition, left, t, l, loc).Resolve (ec);
2556                                         }
2557                                 } else if (r.IsPointer && oper == Operator.Addition){
2558                                         Expression t = Make32or64 (ec, left);
2559                                         if (t != null)
2560                                                 return new PointerArithmetic (true, right, t, r, loc).Resolve (ec);
2561                                 }
2562                         }
2563
2564                         //
2565                         // Enumeration operators
2566                         //
2567                         bool lie = TypeManager.IsEnumType (l);
2568                         bool rie = TypeManager.IsEnumType (r);
2569                         if (lie || rie){
2570                                 Expression temp;
2571
2572                                 // U operator - (E e, E f)
2573                                 if (lie && rie){
2574                                         if (oper == Operator.Subtraction){
2575                                         if (l == r){
2576                                                 type = TypeManager.EnumToUnderlying (l);
2577                                                 return this;
2578                                         }
2579                                         Error_OperatorCannotBeApplied ();
2580                                         return null;
2581                                 }
2582                                 }
2583
2584                                 //
2585                                 // operator + (E e, U x)
2586                                 // operator - (E e, U x)
2587                                 //
2588                                 if (oper == Operator.Addition || oper == Operator.Subtraction){
2589                                         Type enum_type = lie ? l : r;
2590                                         Type other_type = lie ? r : l;
2591                                         Type underlying_type = TypeManager.EnumToUnderlying (enum_type);
2592
2593                                         if (underlying_type != other_type){
2594                                                 temp = Convert.ImplicitConversion (ec, lie ? right : left, underlying_type, loc);
2595                                                 if (temp != null){
2596                                                         if (lie)
2597                                                                 right = temp;
2598                                                         else
2599                                                                 left = temp;
2600                                                         type = enum_type;
2601                                                         return this;
2602                                                 }
2603
2604                                                 Error_OperatorCannotBeApplied ();
2605                                                 return null;
2606                                         }
2607
2608                                         type = enum_type;
2609                                         return this;
2610                                 }
2611
2612                                 if (!rie){
2613                                         temp = Convert.ImplicitConversion (ec, right, l, loc);
2614                                         if (temp != null)
2615                                                 right = temp;
2616                                         else {
2617                                                 Error_OperatorCannotBeApplied ();
2618                                                 return null;
2619                                         }
2620                                 } if (!lie){
2621                                         temp = Convert.ImplicitConversion (ec, left, r, loc);
2622                                         if (temp != null){
2623                                                 left = temp;
2624                                                 l = r;
2625                                         } else {
2626                                                 Error_OperatorCannotBeApplied ();
2627                                                 return null;
2628                                         }
2629                                 }
2630
2631                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2632                                     oper == Operator.LessThanOrEqual || oper == Operator.LessThan ||
2633                                     oper == Operator.GreaterThanOrEqual || oper == Operator.GreaterThan){
2634                                         if (left.Type != right.Type){
2635                                                 Error_OperatorCannotBeApplied ();
2636                                                 return null;
2637                                         }
2638                                         type = TypeManager.bool_type;
2639                                         return this;
2640                                 }
2641
2642                                 if (oper == Operator.BitwiseAnd ||
2643                                     oper == Operator.BitwiseOr ||
2644                                     oper == Operator.ExclusiveOr){
2645                                         if (left.Type != right.Type){
2646                                                 Error_OperatorCannotBeApplied ();
2647                                                 return null;
2648                                         }
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.LessThan || oper == Operator.LessThanOrEqual ||
2694                                     oper == Operator.GreaterThan || oper == Operator.GreaterThanOrEqual){
2695                                         type = TypeManager.bool_type;
2696                                         return this;
2697                                 }
2698                         }
2699
2700                         //
2701                         // This will leave left or right set to null if there is an error
2702                         //
2703                         bool check_user_conv = is_user_defined (l) && is_user_defined (r);
2704                         DoNumericPromotions (ec, l, r, check_user_conv);
2705                         if (left == null || right == null){
2706                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
2707                                 return null;
2708                         }
2709
2710                         //
2711                         // reload our cached types if required
2712                         //
2713                         l = left.Type;
2714                         r = right.Type;
2715
2716                         if (oper == Operator.BitwiseAnd ||
2717                             oper == Operator.BitwiseOr ||
2718                             oper == Operator.ExclusiveOr){
2719                                 if (l == r){
2720                                         if (((l == TypeManager.int32_type) ||
2721                                              (l == TypeManager.uint32_type) ||
2722                                              (l == TypeManager.short_type) ||
2723                                              (l == TypeManager.ushort_type) ||
2724                                              (l == TypeManager.int64_type) ||
2725                                              (l == TypeManager.uint64_type))){
2726                                                 type = l;
2727                                         } else {
2728                                                 Error_OperatorCannotBeApplied ();
2729                                                 return null;
2730                                         }
2731                                 } else {
2732                                         Error_OperatorCannotBeApplied ();
2733                                         return null;
2734                                 }
2735                         }
2736
2737                         if (oper == Operator.Equality ||
2738                             oper == Operator.Inequality ||
2739                             oper == Operator.LessThanOrEqual ||
2740                             oper == Operator.LessThan ||
2741                             oper == Operator.GreaterThanOrEqual ||
2742                             oper == Operator.GreaterThan){
2743                                 type = TypeManager.bool_type;
2744                         }
2745
2746                         return this;
2747                 }
2748
2749                 public override Expression DoResolve (EmitContext ec)
2750                 {
2751                         if ((oper == Operator.Subtraction) && (left is ParenthesizedExpression)) {
2752                                 left = ((ParenthesizedExpression) left).Expr;
2753                                 left = left.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.Type);
2754                                 if (left == null)
2755                                         return null;
2756
2757                                 if (left.eclass == ExprClass.Type) {
2758                                         Error (75, "Casting a negative value needs to have the value in parentheses.");
2759                                         return null;
2760                                 }
2761                         } else
2762                                 left = left.Resolve (ec);
2763
2764                         if (left == null)
2765                                 return null;
2766
2767                         Constant lc = left as Constant;
2768                         if (lc != null && lc.Type == TypeManager.bool_type &&
2769                                 ((oper == Operator.LogicalAnd && (bool)lc.GetValue () == false) ||
2770                                  (oper == Operator.LogicalOr && (bool)lc.GetValue () == true))) {
2771
2772                                 // TODO: make a sense to resolve unreachable expression as we do for statement
2773                                 Report.Warning (429, 4, loc, "Unreachable expression code detected");
2774                                 return left;
2775                         }
2776
2777                         right = right.Resolve (ec);
2778                         if (right == null)
2779                                 return null;
2780
2781                         eclass = ExprClass.Value;
2782
2783                         Constant rc = right as Constant;
2784
2785                         if (oper == Operator.BitwiseAnd) {
2786                                 if (rc != null && rc.IsZeroInteger) {
2787                                         return lc is EnumConstant ?
2788                                                 new EnumConstant (rc, lc.Type):
2789                                                 rc;
2790                                 }
2791
2792                                 if (lc != null && lc.IsZeroInteger) {
2793                                         return rc is EnumConstant ?
2794                                                 new EnumConstant (lc, rc.Type):
2795                                                 lc;
2796                                 }
2797                         }
2798
2799                         if (rc != null && lc != null){
2800                                 Expression e = ConstantFold.BinaryFold (
2801                                         ec, oper, lc, rc, loc);
2802                                 if (e != null)
2803                                         return e;
2804                         }
2805
2806                         if (TypeManager.IsNullableType (left.Type) || TypeManager.IsNullableType (right.Type))
2807                                 return new Nullable.LiftedBinaryOperator (oper, left, right, loc).Resolve (ec);
2808
2809                         return ResolveOperator (ec);
2810                 }
2811
2812                 /// <remarks>
2813                 ///   EmitBranchable is called from Statement.EmitBoolExpression in the
2814                 ///   context of a conditional bool expression.  This function will return
2815                 ///   false if it is was possible to use EmitBranchable, or true if it was.
2816                 ///
2817                 ///   The expression's code is generated, and we will generate a branch to `target'
2818                 ///   if the resulting expression value is equal to isTrue
2819                 /// </remarks>
2820                 public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
2821                 {
2822                         ILGenerator ig = ec.ig;
2823
2824                         //
2825                         // This is more complicated than it looks, but its just to avoid
2826                         // duplicated tests: basically, we allow ==, !=, >, <, >= and <=
2827                         // but on top of that we want for == and != to use a special path
2828                         // if we are comparing against null
2829                         //
2830                         if ((oper == Operator.Equality || oper == Operator.Inequality) && (left is Constant || right is Constant)) {
2831                                 bool my_on_true = oper == Operator.Inequality ? onTrue : !onTrue;
2832
2833                                 //
2834                                 // put the constant on the rhs, for simplicity
2835                                 //
2836                                 if (left is Constant) {
2837                                         Expression swap = right;
2838                                         right = left;
2839                                         left = swap;
2840                                 }
2841
2842                                 if (((Constant) right).IsZeroInteger) {
2843                                         left.Emit (ec);
2844                                         if (my_on_true)
2845                                                 ig.Emit (OpCodes.Brtrue, target);
2846                                         else
2847                                                 ig.Emit (OpCodes.Brfalse, target);
2848
2849                                         return;
2850                                 } else if (right is BoolConstant){
2851                                         left.Emit (ec);
2852                                         if (my_on_true != ((BoolConstant) right).Value)
2853                                                 ig.Emit (OpCodes.Brtrue, target);
2854                                         else
2855                                                 ig.Emit (OpCodes.Brfalse, target);
2856
2857                                         return;
2858                                 }
2859
2860                         } else if (oper == Operator.LogicalAnd) {
2861
2862                                 if (onTrue) {
2863                                                 Label tests_end = ig.DefineLabel ();
2864
2865                                         left.EmitBranchable (ec, tests_end, false);
2866                                         right.EmitBranchable (ec, target, true);
2867                                                         ig.MarkLabel (tests_end);
2868                                         } else {
2869                                         left.EmitBranchable (ec, target, false);
2870                                         right.EmitBranchable (ec, target, false);
2871                                         }
2872
2873                                 return;
2874
2875                         } else if (oper == Operator.LogicalOr){
2876                                 if (onTrue) {
2877                                         left.EmitBranchable (ec, target, true);
2878                                         right.EmitBranchable (ec, target, true);
2879
2880                                         } else {
2881                                                 Label tests_end = ig.DefineLabel ();
2882                                         left.EmitBranchable (ec, tests_end, true);
2883                                         right.EmitBranchable (ec, target, false);
2884                                         ig.MarkLabel (tests_end);
2885                                 }
2886
2887                                 return;
2888
2889                         } else if (!(oper == Operator.LessThan        || oper == Operator.GreaterThan ||
2890                                      oper == Operator.LessThanOrEqual || oper == Operator.GreaterThanOrEqual ||
2891                                      oper == Operator.Equality        || oper == Operator.Inequality)) {
2892                                 base.EmitBranchable (ec, target, onTrue);
2893                                 return;
2894                                 }
2895
2896                         left.Emit (ec);
2897                         right.Emit (ec);
2898
2899                         Type t = left.Type;
2900                         bool isUnsigned = is_unsigned (t) || t == TypeManager.double_type || t == TypeManager.float_type;
2901
2902                         switch (oper){
2903                         case Operator.Equality:
2904                                 if (onTrue)
2905                                         ig.Emit (OpCodes.Beq, target);
2906                                 else
2907                                         ig.Emit (OpCodes.Bne_Un, target);
2908                                 break;
2909
2910                         case Operator.Inequality:
2911                                 if (onTrue)
2912                                         ig.Emit (OpCodes.Bne_Un, target);
2913                                 else
2914                                         ig.Emit (OpCodes.Beq, target);
2915                                 break;
2916
2917                         case Operator.LessThan:
2918                                 if (onTrue)
2919                                         if (isUnsigned)
2920                                                 ig.Emit (OpCodes.Blt_Un, target);
2921                                         else
2922                                                 ig.Emit (OpCodes.Blt, target);
2923                                 else
2924                                         if (isUnsigned)
2925                                                 ig.Emit (OpCodes.Bge_Un, target);
2926                                         else
2927                                                 ig.Emit (OpCodes.Bge, target);
2928                                 break;
2929
2930                         case Operator.GreaterThan:
2931                                 if (onTrue)
2932                                         if (isUnsigned)
2933                                                 ig.Emit (OpCodes.Bgt_Un, target);
2934                                         else
2935                                                 ig.Emit (OpCodes.Bgt, target);
2936                                 else
2937                                         if (isUnsigned)
2938                                                 ig.Emit (OpCodes.Ble_Un, target);
2939                                         else
2940                                                 ig.Emit (OpCodes.Ble, target);
2941                                 break;
2942
2943                         case Operator.LessThanOrEqual:
2944                                 if (onTrue)
2945                                         if (isUnsigned)
2946                                                 ig.Emit (OpCodes.Ble_Un, target);
2947                                         else
2948                                                 ig.Emit (OpCodes.Ble, target);
2949                                 else
2950                                         if (isUnsigned)
2951                                                 ig.Emit (OpCodes.Bgt_Un, target);
2952                                         else
2953                                                 ig.Emit (OpCodes.Bgt, target);
2954                                 break;
2955
2956
2957                         case Operator.GreaterThanOrEqual:
2958                                 if (onTrue)
2959                                         if (isUnsigned)
2960                                                 ig.Emit (OpCodes.Bge_Un, target);
2961                                         else
2962                                                 ig.Emit (OpCodes.Bge, target);
2963                                 else
2964                                         if (isUnsigned)
2965                                                 ig.Emit (OpCodes.Blt_Un, target);
2966                                         else
2967                                                 ig.Emit (OpCodes.Blt, target);
2968                                 break;
2969                         default:
2970                                 Console.WriteLine (oper);
2971                                 throw new Exception ("what is THAT");
2972                         }
2973                 }
2974
2975                 public override void Emit (EmitContext ec)
2976                 {
2977                         ILGenerator ig = ec.ig;
2978                         Type l = left.Type;
2979                         OpCode opcode;
2980
2981                         //
2982                         // Handle short-circuit operators differently
2983                         // than the rest
2984                         //
2985                         if (oper == Operator.LogicalAnd) {
2986                                 Label load_zero = ig.DefineLabel ();
2987                                 Label end = ig.DefineLabel ();
2988
2989                                 left.EmitBranchable (ec, load_zero, false);
2990                                                 right.Emit (ec);
2991                                                 ig.Emit (OpCodes.Br, end);
2992
2993                                 ig.MarkLabel (load_zero);
2994                                 ig.Emit (OpCodes.Ldc_I4_0);
2995                                 ig.MarkLabel (end);
2996                                 return;
2997                         } else if (oper == Operator.LogicalOr) {
2998                                 Label load_one = ig.DefineLabel ();
2999                                 Label end = ig.DefineLabel ();
3000
3001                                 left.EmitBranchable (ec, load_one, true);
3002                                                 right.Emit (ec);
3003                                                 ig.Emit (OpCodes.Br, end);
3004
3005                                 ig.MarkLabel (load_one);
3006                                 ig.Emit (OpCodes.Ldc_I4_1);
3007                                 ig.MarkLabel (end);
3008                                 return;
3009                         }
3010
3011                         left.Emit (ec);
3012                         right.Emit (ec);
3013
3014                         bool isUnsigned = is_unsigned (left.Type);
3015
3016                         switch (oper){
3017                         case Operator.Multiply:
3018                                 if (ec.CheckState){
3019                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
3020                                                 opcode = OpCodes.Mul_Ovf;
3021                                         else if (isUnsigned)
3022                                                 opcode = OpCodes.Mul_Ovf_Un;
3023                                         else
3024                                                 opcode = OpCodes.Mul;
3025                                 } else
3026                                         opcode = OpCodes.Mul;
3027
3028                                 break;
3029
3030                         case Operator.Division:
3031                                 if (isUnsigned)
3032                                         opcode = OpCodes.Div_Un;
3033                                 else
3034                                         opcode = OpCodes.Div;
3035                                 break;
3036
3037                         case Operator.Modulus:
3038                                 if (isUnsigned)
3039                                         opcode = OpCodes.Rem_Un;
3040                                 else
3041                                         opcode = OpCodes.Rem;
3042                                 break;
3043
3044                         case Operator.Addition:
3045                                 if (ec.CheckState){
3046                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
3047                                                 opcode = OpCodes.Add_Ovf;
3048                                         else if (isUnsigned)
3049                                                 opcode = OpCodes.Add_Ovf_Un;
3050                                         else
3051                                                 opcode = OpCodes.Add;
3052                                 } else
3053                                         opcode = OpCodes.Add;
3054                                 break;
3055
3056                         case Operator.Subtraction:
3057                                 if (ec.CheckState){
3058                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
3059                                                 opcode = OpCodes.Sub_Ovf;
3060                                         else if (isUnsigned)
3061                                                 opcode = OpCodes.Sub_Ovf_Un;
3062                                         else
3063                                                 opcode = OpCodes.Sub;
3064                                 } else
3065                                         opcode = OpCodes.Sub;
3066                                 break;
3067
3068                         case Operator.RightShift:
3069                                 if (isUnsigned)
3070                                         opcode = OpCodes.Shr_Un;
3071                                 else
3072                                         opcode = OpCodes.Shr;
3073                                 break;
3074
3075                         case Operator.LeftShift:
3076                                 opcode = OpCodes.Shl;
3077                                 break;
3078
3079                         case Operator.Equality:
3080                                 opcode = OpCodes.Ceq;
3081                                 break;
3082
3083                         case Operator.Inequality:
3084                                 ig.Emit (OpCodes.Ceq);
3085                                 ig.Emit (OpCodes.Ldc_I4_0);
3086
3087                                 opcode = OpCodes.Ceq;
3088                                 break;
3089
3090                         case Operator.LessThan:
3091                                 if (isUnsigned)
3092                                         opcode = OpCodes.Clt_Un;
3093                                 else
3094                                         opcode = OpCodes.Clt;
3095                                 break;
3096
3097                         case Operator.GreaterThan:
3098                                 if (isUnsigned)
3099                                         opcode = OpCodes.Cgt_Un;
3100                                 else
3101                                         opcode = OpCodes.Cgt;
3102                                 break;
3103
3104                         case Operator.LessThanOrEqual:
3105                                 Type lt = left.Type;
3106
3107                                 if (isUnsigned || (lt == TypeManager.double_type || lt == TypeManager.float_type))
3108                                         ig.Emit (OpCodes.Cgt_Un);
3109                                 else
3110                                         ig.Emit (OpCodes.Cgt);
3111                                 ig.Emit (OpCodes.Ldc_I4_0);
3112
3113                                 opcode = OpCodes.Ceq;
3114                                 break;
3115
3116                         case Operator.GreaterThanOrEqual:
3117                                 Type le = left.Type;
3118
3119                                 if (isUnsigned || (le == TypeManager.double_type || le == TypeManager.float_type))
3120                                         ig.Emit (OpCodes.Clt_Un);
3121                                 else
3122                                         ig.Emit (OpCodes.Clt);
3123
3124                                 ig.Emit (OpCodes.Ldc_I4_0);
3125
3126                                 opcode = OpCodes.Ceq;
3127                                 break;
3128
3129                         case Operator.BitwiseOr:
3130                                 opcode = OpCodes.Or;
3131                                 break;
3132
3133                         case Operator.BitwiseAnd:
3134                                 opcode = OpCodes.And;
3135                                 break;
3136
3137                         case Operator.ExclusiveOr:
3138                                 opcode = OpCodes.Xor;
3139                                 break;
3140
3141                         default:
3142                                 throw new Exception ("This should not happen: Operator = "
3143                                                      + oper.ToString ());
3144                         }
3145
3146                         ig.Emit (opcode);
3147                 }
3148         }
3149
3150         //
3151         // Object created by Binary when the binary operator uses an method instead of being
3152         // a binary operation that maps to a CIL binary operation.
3153         //
3154         public class BinaryMethod : Expression {
3155                 public MethodBase method;
3156                 public ArrayList  Arguments;
3157
3158                 public BinaryMethod (Type t, MethodBase m, ArrayList args)
3159                 {
3160                         method = m;
3161                         Arguments = args;
3162                         type = t;
3163                         eclass = ExprClass.Value;
3164                 }
3165
3166                 public override Expression DoResolve (EmitContext ec)
3167                 {
3168                         return this;
3169                 }
3170
3171                 public override void Emit (EmitContext ec)
3172                 {
3173                         ILGenerator ig = ec.ig;
3174
3175                         if (Arguments != null)
3176                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
3177
3178                         if (method is MethodInfo)
3179                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
3180                         else
3181                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
3182                 }
3183         }
3184
3185         //
3186         // Represents the operation a + b [+ c [+ d [+ ...]]], where a is a string
3187         // b, c, d... may be strings or objects.
3188         //
3189         public class StringConcat : Expression {
3190                 ArrayList operands;
3191                 bool invalid = false;
3192                 bool emit_conv_done = false;
3193                 //
3194                 // Are we also concating objects?
3195                 //
3196                 bool is_strings_only = true;
3197
3198                 public StringConcat (EmitContext ec, Location loc, Expression left, Expression right)
3199                 {
3200                         this.loc = loc;
3201                         type = TypeManager.string_type;
3202                         eclass = ExprClass.Value;
3203
3204                         operands = new ArrayList (2);
3205                         Append (ec, left);
3206                         Append (ec, right);
3207                 }
3208
3209                 public override Expression DoResolve (EmitContext ec)
3210                 {
3211                         if (invalid)
3212                                 return null;
3213
3214                         return this;
3215                 }
3216
3217                 public void Append (EmitContext ec, Expression operand)
3218                 {
3219                         //
3220                         // Constant folding
3221                         //
3222                         if (operand is StringConstant && operands.Count != 0) {
3223                                 StringConstant last_operand = operands [operands.Count - 1] as StringConstant;
3224                                 if (last_operand != null) {
3225                                         operands [operands.Count - 1] = new StringConstant (last_operand.Value + ((StringConstant) operand).Value);
3226                                         return;
3227                                 }
3228                         }
3229
3230                         //
3231                         // Conversion to object
3232                         //
3233                         if (operand.Type != TypeManager.string_type) {
3234                                 Expression no = Convert.ImplicitConversion (ec, operand, TypeManager.object_type, loc);
3235
3236                                 if (no == null) {
3237                                         Binary.Error_OperatorCannotBeApplied (loc, "+", TypeManager.string_type, operand.Type);
3238                                         invalid = true;
3239                                 }
3240                                 operand = no;
3241                         }
3242
3243                         operands.Add (operand);
3244                 }
3245
3246                 public override void Emit (EmitContext ec)
3247                 {
3248                         MethodInfo concat_method = null;
3249
3250                         //
3251                         // Do conversion to arguments; check for strings only
3252                         //
3253
3254                         // This can get called multiple times, so we have to deal with that.
3255                         if (!emit_conv_done) {
3256                                 emit_conv_done = true;
3257                         for (int i = 0; i < operands.Count; i ++) {
3258                                 Expression e = (Expression) operands [i];
3259                                 is_strings_only &= e.Type == TypeManager.string_type;
3260                         }
3261
3262                         for (int i = 0; i < operands.Count; i ++) {
3263                                 Expression e = (Expression) operands [i];
3264
3265                                 if (! is_strings_only && e.Type == TypeManager.string_type) {
3266                                         // need to make sure this is an object, because the EmitParams
3267                                         // method might look at the type of this expression, see it is a
3268                                         // string and emit a string [] when we want an object [];
3269
3270                                                 e = new EmptyCast (e, TypeManager.object_type);
3271                                 }
3272                                 operands [i] = new Argument (e, Argument.AType.Expression);
3273                         }
3274                         }
3275
3276                         //
3277                         // Find the right method
3278                         //
3279                         switch (operands.Count) {
3280                         case 1:
3281                                 //
3282                                 // This should not be possible, because simple constant folding
3283                                 // is taken care of in the Binary code.
3284                                 //
3285                                 throw new Exception ("how did you get here?");
3286
3287                         case 2:
3288                                 concat_method = is_strings_only ?
3289                                         TypeManager.string_concat_string_string :
3290                                         TypeManager.string_concat_object_object ;
3291                                 break;
3292                         case 3:
3293                                 concat_method = is_strings_only ?
3294                                         TypeManager.string_concat_string_string_string :
3295                                         TypeManager.string_concat_object_object_object ;
3296                                 break;
3297                         case 4:
3298                                 //
3299                                 // There is not a 4 param overlaod for object (the one that there is
3300                                 // is actually a varargs methods, and is only in corlib because it was
3301                                 // introduced there before.).
3302                                 //
3303                                 if (!is_strings_only)
3304                                         goto default;
3305
3306                                 concat_method = TypeManager.string_concat_string_string_string_string;
3307                                 break;
3308                         default:
3309                                 concat_method = is_strings_only ?
3310                                         TypeManager.string_concat_string_dot_dot_dot :
3311                                         TypeManager.string_concat_object_dot_dot_dot ;
3312                                 break;
3313                         }
3314
3315                         Invocation.EmitArguments (ec, concat_method, operands, false, null);
3316                         ec.ig.Emit (OpCodes.Call, concat_method);
3317                 }
3318         }
3319
3320         //
3321         // Object created with +/= on delegates
3322         //
3323         public class BinaryDelegate : Expression {
3324                 MethodInfo method;
3325                 ArrayList  args;
3326
3327                 public BinaryDelegate (Type t, MethodInfo mi, ArrayList args)
3328                 {
3329                         method = mi;
3330                         this.args = args;
3331                         type = t;
3332                         eclass = ExprClass.Value;
3333                 }
3334
3335                 public override Expression DoResolve (EmitContext ec)
3336                 {
3337                         return this;
3338                 }
3339
3340                 public override void Emit (EmitContext ec)
3341                 {
3342                         ILGenerator ig = ec.ig;
3343
3344                         Invocation.EmitArguments (ec, method, args, false, null);
3345
3346                         ig.Emit (OpCodes.Call, (MethodInfo) method);
3347                         ig.Emit (OpCodes.Castclass, type);
3348                 }
3349
3350                 public Expression Right {
3351                         get {
3352                                 Argument arg = (Argument) args [1];
3353                                 return arg.Expr;
3354                         }
3355                 }
3356
3357                 public bool IsAddition {
3358                         get {
3359                                 return method == TypeManager.delegate_combine_delegate_delegate;
3360                         }
3361                 }
3362         }
3363
3364         //
3365         // User-defined conditional logical operator
3366         public class ConditionalLogicalOperator : Expression {
3367                 Expression left, right;
3368                 bool is_and;
3369
3370                 public ConditionalLogicalOperator (bool is_and, Expression left, Expression right, Type t, Location loc)
3371                 {
3372                         type = t;
3373                         eclass = ExprClass.Value;
3374                         this.loc = loc;
3375                         this.left = left;
3376                         this.right = right;
3377                         this.is_and = is_and;
3378                 }
3379
3380                 protected void Error19 ()
3381                 {
3382                         Binary.Error_OperatorCannotBeApplied (loc, is_and ? "&&" : "||", type, type);
3383                 }
3384
3385                 protected void Error218 ()
3386                 {
3387                         Error (218, "The type ('" + TypeManager.CSharpName (type) + "') must contain " +
3388                                "declarations of operator true and operator false");
3389                 }
3390
3391                 Expression op_true, op_false, op;
3392                 LocalTemporary left_temp;
3393
3394                 public override Expression DoResolve (EmitContext ec)
3395                 {
3396                         MethodInfo method;
3397                         Expression operator_group;
3398
3399                         operator_group = MethodLookup (ec, type, is_and ? "op_BitwiseAnd" : "op_BitwiseOr", loc);
3400                         if (operator_group == null) {
3401                                 Error19 ();
3402                                 return null;
3403                         }
3404
3405                         left_temp = new LocalTemporary (ec, type);
3406
3407                         ArrayList arguments = new ArrayList ();
3408                         arguments.Add (new Argument (left_temp, Argument.AType.Expression));
3409                         arguments.Add (new Argument (right, Argument.AType.Expression));
3410                         method = Invocation.OverloadResolve (
3411                                 ec, (MethodGroupExpr) operator_group, arguments, false, loc)
3412                                 as MethodInfo;
3413                         if (method == null) {
3414                                 Error19 ();
3415                                 return null;
3416                         }
3417
3418                         if (method.ReturnType != type) {
3419                                 Report.Error (217, loc, "In order to be applicable as a short circuit operator a user-defined logical operator ('{0}') " +
3420                                                 "must have the same return type as the type of its 2 parameters", TypeManager.CSharpSignature (method));
3421                                 return null;
3422                         }
3423
3424                         op = new StaticCallExpr (method, arguments, loc);
3425
3426                         op_true = GetOperatorTrue (ec, left_temp, loc);
3427                         op_false = GetOperatorFalse (ec, left_temp, loc);
3428                         if ((op_true == null) || (op_false == null)) {
3429                                 Error218 ();
3430                                 return null;
3431                         }
3432
3433                         return this;
3434                 }
3435
3436                 public override void Emit (EmitContext ec)
3437                 {
3438                         ILGenerator ig = ec.ig;
3439                         Label false_target = ig.DefineLabel ();
3440                         Label end_target = ig.DefineLabel ();
3441
3442                         left.Emit (ec);
3443                         left_temp.Store (ec);
3444
3445                         (is_and ? op_false : op_true).EmitBranchable (ec, false_target, false);
3446                         left_temp.Emit (ec);
3447                         ig.Emit (OpCodes.Br, end_target);
3448                         ig.MarkLabel (false_target);
3449                         op.Emit (ec);
3450                         ig.MarkLabel (end_target);
3451                 }
3452         }
3453
3454         public class PointerArithmetic : Expression {
3455                 Expression left, right;
3456                 bool is_add;
3457
3458                 //
3459                 // We assume that `l' is always a pointer
3460                 //
3461                 public PointerArithmetic (bool is_addition, Expression l, Expression r, Type t, Location loc)
3462                 {
3463                         type = t;
3464                         this.loc = loc;
3465                         left = l;
3466                         right = r;
3467                         is_add = is_addition;
3468                 }
3469
3470                 public override Expression DoResolve (EmitContext ec)
3471                 {
3472                         eclass = ExprClass.Variable;
3473
3474                         if (left.Type == TypeManager.void_ptr_type) {
3475                                 Error (242, "The operation in question is undefined on void pointers");
3476                                 return null;
3477                         }
3478
3479                         return this;
3480                 }
3481
3482                 public override void Emit (EmitContext ec)
3483                 {
3484                         Type op_type = left.Type;
3485                         ILGenerator ig = ec.ig;
3486
3487                         // It must be either array or fixed buffer
3488                         Type element = TypeManager.HasElementType (op_type) ?
3489                                 element = TypeManager.GetElementType (op_type) :
3490                                 element = AttributeTester.GetFixedBuffer (((FieldExpr)left).FieldInfo).ElementType;
3491
3492                         int size = GetTypeSize (element);
3493                         Type rtype = right.Type;
3494
3495                         if (rtype.IsPointer){
3496                                 //
3497                                 // handle (pointer - pointer)
3498                                 //
3499                                 left.Emit (ec);
3500                                 right.Emit (ec);
3501                                 ig.Emit (OpCodes.Sub);
3502
3503                                 if (size != 1){
3504                                         if (size == 0)
3505                                                 ig.Emit (OpCodes.Sizeof, element);
3506                                         else
3507                                                 IntLiteral.EmitInt (ig, size);
3508                                         ig.Emit (OpCodes.Div);
3509                                 }
3510                                 ig.Emit (OpCodes.Conv_I8);
3511                         } else {
3512                                 //
3513                                 // handle + and - on (pointer op int)
3514                                 //
3515                                 left.Emit (ec);
3516                                 ig.Emit (OpCodes.Conv_I);
3517
3518                                 Constant right_const = right as Constant;
3519                                 if (right_const != null && size != 0) {
3520                                         Expression ex = ConstantFold.BinaryFold (ec, Binary.Operator.Multiply, new IntConstant (size), right_const, loc);
3521                                         if (ex == null)
3522                                                 return;
3523                                         ex.Emit (ec);
3524                                 } else {
3525                                         right.Emit (ec);
3526                                         if (size != 1){
3527                                                 if (size == 0)
3528                                                         ig.Emit (OpCodes.Sizeof, element);
3529                                                 else
3530                                                         IntLiteral.EmitInt (ig, size);
3531                                                 if (rtype == TypeManager.int64_type)
3532                                                         ig.Emit (OpCodes.Conv_I8);
3533                                                 else if (rtype == TypeManager.uint64_type)
3534                                                         ig.Emit (OpCodes.Conv_U8);
3535                                                 ig.Emit (OpCodes.Mul);
3536                                         }
3537                                 }
3538
3539                                 if (rtype == TypeManager.int64_type || rtype == TypeManager.uint64_type)
3540                                         ig.Emit (OpCodes.Conv_I);
3541
3542                                 if (is_add)
3543                                         ig.Emit (OpCodes.Add);
3544                                 else
3545                                         ig.Emit (OpCodes.Sub);
3546                         }
3547                 }
3548         }
3549
3550         /// <summary>
3551         ///   Implements the ternary conditional operator (?:)
3552         /// </summary>
3553         public class Conditional : Expression {
3554                 Expression expr, trueExpr, falseExpr;
3555
3556                 public Conditional (Expression expr, Expression trueExpr, Expression falseExpr, Location l)
3557                 {
3558                         this.expr = expr;
3559                         this.trueExpr = trueExpr;
3560                         this.falseExpr = falseExpr;
3561                         this.loc = l;
3562                 }
3563
3564                 public Expression Expr {
3565                         get {
3566                                 return expr;
3567                         }
3568                 }
3569
3570                 public Expression TrueExpr {
3571                         get {
3572                                 return trueExpr;
3573                         }
3574                 }
3575
3576                 public Expression FalseExpr {
3577                         get {
3578                                 return falseExpr;
3579                         }
3580                 }
3581
3582                 public override Expression DoResolve (EmitContext ec)
3583                 {
3584                         expr = expr.Resolve (ec);
3585
3586                         if (expr == null)
3587                                 return null;
3588
3589                         if (TypeManager.IsNullableType (expr.Type))
3590                                 return new Nullable.LiftedConditional (expr, trueExpr, falseExpr, loc).Resolve (ec);
3591
3592                         if (expr.Type != TypeManager.bool_type){
3593                                 expr = Expression.ResolveBoolean (
3594                                         ec, expr, loc);
3595
3596                                 if (expr == null)
3597                                         return null;
3598                         }
3599
3600                         trueExpr = trueExpr.Resolve (ec);
3601                         falseExpr = falseExpr.Resolve (ec);
3602
3603                         if (trueExpr == null || falseExpr == null)
3604                                 return null;
3605
3606                         eclass = ExprClass.Value;
3607                         if (trueExpr.Type == falseExpr.Type)
3608                                 type = trueExpr.Type;
3609                         else {
3610                                 Expression conv;
3611                                 Type true_type = trueExpr.Type;
3612                                 Type false_type = falseExpr.Type;
3613
3614                                 //
3615                                 // First, if an implicit conversion exists from trueExpr
3616                                 // to falseExpr, then the result type is of type falseExpr.Type
3617                                 //
3618                                 conv = Convert.ImplicitConversion (ec, trueExpr, false_type, loc);
3619                                 if (conv != null){
3620                                         //
3621                                         // Check if both can convert implicitl to each other's type
3622                                         //
3623                                         if (Convert.ImplicitConversion (ec, falseExpr, true_type, loc) != null){
3624                                                 Error (172,
3625                                                        "Can not compute type of conditional expression " +
3626                                                        "as `" + TypeManager.CSharpName (trueExpr.Type) +
3627                                                        "' and `" + TypeManager.CSharpName (falseExpr.Type) +
3628                                                        "' convert implicitly to each other");
3629                                                 return null;
3630                                         }
3631                                         type = false_type;
3632                                         trueExpr = conv;
3633                                 } else if ((conv = Convert.ImplicitConversion(ec, falseExpr, true_type,loc))!= null){
3634                                         type = true_type;
3635                                         falseExpr = conv;
3636                                 } else {
3637                                         Error (173, "The type of the conditional expression can " +
3638                                                "not be computed because there is no implicit conversion" +
3639                                                " from `" + TypeManager.CSharpName (trueExpr.Type) + "'" +
3640                                                " and `" + TypeManager.CSharpName (falseExpr.Type) + "'");
3641                                         return null;
3642                                 }
3643                         }
3644
3645                         // Dead code optimalization
3646                         if (expr is BoolConstant){
3647                                 BoolConstant bc = (BoolConstant) expr;
3648
3649                                 Report.Warning (429, 4, bc.Value ? falseExpr.Location : trueExpr.Location, "Unreachable expression code detected");
3650                                 return bc.Value ? trueExpr : falseExpr;
3651                         }
3652
3653                         return this;
3654                 }
3655
3656                 public override void Emit (EmitContext ec)
3657                 {
3658                         ILGenerator ig = ec.ig;
3659                         Label false_target = ig.DefineLabel ();
3660                         Label end_target = ig.DefineLabel ();
3661
3662                         expr.EmitBranchable (ec, false_target, false);
3663                         trueExpr.Emit (ec);
3664                         ig.Emit (OpCodes.Br, end_target);
3665                         ig.MarkLabel (false_target);
3666                         falseExpr.Emit (ec);
3667                         ig.MarkLabel (end_target);
3668                 }
3669
3670         }
3671
3672         /// <summary>
3673         ///   Local variables
3674         /// </summary>
3675         public class LocalVariableReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
3676                 public readonly string Name;
3677                 public readonly Block Block;
3678                 public LocalInfo local_info;
3679                 bool is_readonly;
3680                 bool prepared;
3681                 LocalTemporary temp;
3682
3683                 public LocalVariableReference (Block block, string name, Location l)
3684                 {
3685                         Block = block;
3686                         Name = name;
3687                         loc = l;
3688                         eclass = ExprClass.Variable;
3689                 }
3690
3691                 //
3692                 // Setting `is_readonly' to false will allow you to create a writable
3693                 // reference to a read-only variable.  This is used by foreach and using.
3694                 //
3695                 public LocalVariableReference (Block block, string name, Location l,
3696                                                LocalInfo local_info, bool is_readonly)
3697                         : this (block, name, l)
3698                 {
3699                         this.local_info = local_info;
3700                         this.is_readonly = is_readonly;
3701                 }
3702
3703                 public VariableInfo VariableInfo {
3704                         get {
3705                                 return local_info.VariableInfo;
3706                         }
3707                 }
3708
3709                 public bool IsReadOnly {
3710                         get {
3711                                 return is_readonly;
3712                         }
3713                 }
3714
3715                 protected Expression DoResolveBase (EmitContext ec, Expression lvalue_right_side)
3716                 {
3717                         if (local_info == null) {
3718                                 local_info = Block.GetLocalInfo (Name);
3719
3720                                 // is out param
3721                                 if (lvalue_right_side == EmptyExpression.Null)
3722                                         local_info.Used = true;
3723
3724                                 is_readonly = local_info.ReadOnly;
3725                         }
3726
3727                         type = local_info.VariableType;
3728
3729                         VariableInfo variable_info = local_info.VariableInfo;
3730                         if (lvalue_right_side != null){
3731                                 if (is_readonly){
3732                                         if (lvalue_right_side is LocalVariableReference || lvalue_right_side == EmptyExpression.Null)
3733                                                 Report.Error (1657, loc, "Cannot pass '{0}' with '{1}' modifier because it is a '{2}'",
3734                                                         Name, lvalue_right_side == EmptyExpression.Null ? "out" : "ref",
3735                                                         local_info.GetReadOnlyContext ());
3736                                         else
3737                                                 Report.Error (1656, loc, "Cannot assign to '{0}' because it is a '{1}'",
3738                                                         Name, local_info.GetReadOnlyContext ());
3739                                         return null;
3740                                 }
3741
3742                                 if (variable_info != null)
3743                                         variable_info.SetAssigned (ec);
3744                         }
3745
3746                         Expression e = Block.GetConstantExpression (Name);
3747                         if (e != null) {
3748                                 local_info.Used = true;
3749                                 eclass = ExprClass.Value;
3750                                 return e.Resolve (ec);
3751                         }
3752
3753                         if ((variable_info != null) && !variable_info.IsAssigned (ec, loc))
3754                                 return null;
3755
3756                         if (lvalue_right_side == null)
3757                                 local_info.Used = true;
3758
3759                         if (ec.CurrentAnonymousMethod != null){
3760                                 //
3761                                 // If we are referencing a variable from the external block
3762                                 // flag it for capturing
3763                                 //
3764                                 if (local_info.Block.Toplevel != ec.CurrentBlock.Toplevel){
3765                                         if (local_info.AddressTaken){
3766                                                 AnonymousMethod.Error_AddressOfCapturedVar (local_info.Name, loc);
3767                                                 return null;
3768                                         }
3769                                         ec.CaptureVariable (local_info);
3770                                 }
3771                         }
3772
3773                         return this;
3774                 }
3775
3776                 public override Expression DoResolve (EmitContext ec)
3777                 {
3778                         return DoResolveBase (ec, null);
3779                 }
3780
3781                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3782                 {
3783                         Expression ret = DoResolveBase (ec, right_side);
3784                         if (ret != null)
3785                                 CheckObsoleteAttribute (ret.Type);
3786
3787                         return ret;
3788                 }
3789
3790                 public bool VerifyFixed (bool is_expression)
3791                 {
3792                         return !is_expression || local_info.IsFixed;
3793                 }
3794
3795                 public override int GetHashCode()
3796                 {
3797                         return Name.GetHashCode ();
3798                 }
3799
3800                 public override bool Equals (object obj)
3801                 {
3802                         LocalVariableReference lvr = obj as LocalVariableReference;
3803                         if (lvr == null)
3804                                 return false;
3805
3806                         return Name == lvr.Name && Block == lvr.Block;
3807                 }
3808
3809                 public override void Emit (EmitContext ec)
3810                 {
3811                         ILGenerator ig = ec.ig;
3812
3813                         if (local_info.FieldBuilder == null){
3814                                 //
3815                                 // A local variable on the local CLR stack
3816                                 //
3817                         ig.Emit (OpCodes.Ldloc, local_info.LocalBuilder);
3818                         } else {
3819                                 //
3820                                 // A local variable captured by anonymous methods.
3821                                 //
3822                                 if (!prepared)
3823                                         ec.EmitCapturedVariableInstance (local_info);
3824
3825                                 ig.Emit (OpCodes.Ldfld, local_info.FieldBuilder);
3826                         }
3827                 }
3828
3829                 public void Emit (EmitContext ec, bool leave_copy)
3830                 {
3831                         Emit (ec);
3832                         if (leave_copy){
3833                                 ec.ig.Emit (OpCodes.Dup);
3834                                 if (local_info.FieldBuilder != null){
3835                                         temp = new LocalTemporary (ec, Type);
3836                                         temp.Store (ec);
3837                                 }
3838                         }
3839                 }
3840
3841                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3842                 {
3843                         ILGenerator ig = ec.ig;
3844                         prepared = prepare_for_load;
3845
3846                         if (local_info.FieldBuilder == null){
3847                                 //
3848                                 // A local variable on the local CLR stack
3849                                 //
3850                                 if (local_info.LocalBuilder == null)
3851                                         throw new Exception ("This should not happen: both Field and Local are null");
3852
3853                                 source.Emit (ec);
3854                                 if (leave_copy)
3855                                         ec.ig.Emit (OpCodes.Dup);
3856                                 ig.Emit (OpCodes.Stloc, local_info.LocalBuilder);
3857                         } else {
3858                                 //
3859                                 // A local variable captured by anonymous methods or itereators.
3860                                 //
3861                                 ec.EmitCapturedVariableInstance (local_info);
3862
3863                                 if (prepare_for_load)
3864                                         ig.Emit (OpCodes.Dup);
3865                                 source.Emit (ec);
3866                                 if (leave_copy){
3867                                         ig.Emit (OpCodes.Dup);
3868                                         temp = new LocalTemporary (ec, Type);
3869                                         temp.Store (ec);
3870                                 }
3871                                 ig.Emit (OpCodes.Stfld, local_info.FieldBuilder);
3872                                 if (temp != null)
3873                                         temp.Emit (ec);
3874                         }
3875                 }
3876
3877                 public void AddressOf (EmitContext ec, AddressOp mode)
3878                 {
3879                         ILGenerator ig = ec.ig;
3880
3881                         if (local_info.FieldBuilder == null){
3882                                 //
3883                                 // A local variable on the local CLR stack
3884                                 //
3885                         ig.Emit (OpCodes.Ldloca, local_info.LocalBuilder);
3886                         } else {
3887                                 //
3888                                 // A local variable captured by anonymous methods or iterators
3889                                 //
3890                                 ec.EmitCapturedVariableInstance (local_info);
3891                                 ig.Emit (OpCodes.Ldflda, local_info.FieldBuilder);
3892                         }
3893                 }
3894
3895                 public override string ToString ()
3896                 {
3897                         return String.Format ("{0} ({1}:{2})", GetType (), Name, loc);
3898                 }
3899         }
3900
3901         /// <summary>
3902         ///   This represents a reference to a parameter in the intermediate
3903         ///   representation.
3904         /// </summary>
3905         public class ParameterReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
3906                 Parameters pars;
3907                 String name;
3908                 int idx;
3909                 Block block;
3910                 VariableInfo vi;
3911                 public Parameter.Modifier mod;
3912                 public bool is_ref, is_out, prepared;
3913
3914                 public bool IsOut {
3915                         get {
3916                                 return is_out;
3917                         }
3918                 }
3919
3920                 public bool IsRef {
3921                         get {
3922                                 return is_ref;
3923                         }
3924                 }
3925
3926                 LocalTemporary temp;
3927
3928                 public ParameterReference (Parameters pars, Block block, int idx, string name, Location loc)
3929                 {
3930                         this.pars = pars;
3931                         this.block = block;
3932                         this.idx  = idx;
3933                         this.name = name;
3934                         this.loc = loc;
3935                         eclass = ExprClass.Variable;
3936                 }
3937
3938                 public VariableInfo VariableInfo {
3939                         get { return vi; }
3940                 }
3941
3942                 public bool VerifyFixed (bool is_expression)
3943                 {
3944                         return !is_expression || TypeManager.IsValueType (type);
3945                 }
3946
3947                 public bool IsAssigned (EmitContext ec, Location loc)
3948                 {
3949                         if (!ec.DoFlowAnalysis || !is_out || ec.CurrentBranching.IsAssigned (vi))
3950                                 return true;
3951
3952                         Report.Error (269, loc,
3953                                       "Use of unassigned out parameter '{0}'", name);
3954                         return false;
3955                 }
3956
3957                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
3958                 {
3959                         if (!ec.DoFlowAnalysis || !is_out || ec.CurrentBranching.IsFieldAssigned (vi, field_name))
3960                                 return true;
3961
3962                         Report.Error (170, loc,
3963                                       "Use of possibly unassigned field `" + field_name + "'");
3964                         return false;
3965                 }
3966
3967                 public void SetAssigned (EmitContext ec)
3968                 {
3969                         if (is_out && ec.DoFlowAnalysis)
3970                                 ec.CurrentBranching.SetAssigned (vi);
3971                 }
3972
3973                 public void SetFieldAssigned (EmitContext ec, string field_name)
3974                 {
3975                         if (is_out && ec.DoFlowAnalysis)
3976                                 ec.CurrentBranching.SetFieldAssigned (vi, field_name);
3977                 }
3978
3979                 protected void DoResolveBase (EmitContext ec)
3980                 {
3981                         type = pars.GetParameterInfo (ec, idx, out mod);
3982                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3983                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3984                         eclass = ExprClass.Variable;
3985
3986                         if (is_out)
3987                                 vi = block.ParameterMap [idx];
3988
3989                         if (ec.CurrentAnonymousMethod != null){
3990                                 if (is_ref){
3991                                         Report.Error (1628, Location,
3992                                                       "Can not reference a ref or out parameter in an anonymous method");
3993                                         return;
3994                                 }
3995
3996                                 //
3997                                 // If we are referencing the parameter from the external block
3998                                 // flag it for capturing
3999                                 //
4000                                 //Console.WriteLine ("Is parameter `{0}' local? {1}", name, block.IsLocalParameter (name));
4001                                 if (!block.Toplevel.IsLocalParameter (name)){
4002                                         ec.CaptureParameter (name, type, idx);
4003                                 }
4004                         }
4005                 }
4006
4007                 public override int GetHashCode()
4008                 {
4009                         return name.GetHashCode ();
4010                 }
4011
4012                 public override bool Equals (object obj)
4013                 {
4014                         ParameterReference pr = obj as ParameterReference;
4015                         if (pr == null)
4016                                 return false;
4017
4018                         return name == pr.name && block == pr.block;
4019                 }
4020
4021                 //
4022                 // Notice that for ref/out parameters, the type exposed is not the
4023                 // same type exposed externally.
4024                 //
4025                 // for "ref int a":
4026                 //   externally we expose "int&"
4027                 //   here we expose       "int".
4028                 //
4029                 // We record this in "is_ref".  This means that the type system can treat
4030                 // the type as it is expected, but when we generate the code, we generate
4031                 // the alternate kind of code.
4032                 //
4033                 public override Expression DoResolve (EmitContext ec)
4034                 {
4035                         DoResolveBase (ec);
4036
4037                         if (is_out && ec.DoFlowAnalysis && !IsAssigned (ec, loc))
4038                                 return null;
4039
4040                         if (ec.RemapToProxy)
4041                                 return ec.RemapParameter (idx);
4042
4043                         return this;
4044                 }
4045
4046                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4047                 {
4048                         DoResolveBase (ec);
4049
4050                         SetAssigned (ec);
4051
4052                         if (ec.RemapToProxy)
4053                                 return ec.RemapParameterLValue (idx, right_side);
4054
4055                         return this;
4056                 }
4057
4058                 static public void EmitLdArg (ILGenerator ig, int x)
4059                 {
4060                         if (x <= 255){
4061                                 switch (x){
4062                                 case 0: ig.Emit (OpCodes.Ldarg_0); break;
4063                                 case 1: ig.Emit (OpCodes.Ldarg_1); break;
4064                                 case 2: ig.Emit (OpCodes.Ldarg_2); break;
4065                                 case 3: ig.Emit (OpCodes.Ldarg_3); break;
4066                                 default: ig.Emit (OpCodes.Ldarg_S, (byte) x); break;
4067                                 }
4068                         } else
4069                                 ig.Emit (OpCodes.Ldarg, x);
4070                 }
4071
4072                 //
4073                 // This method is used by parameters that are references, that are
4074                 // being passed as references:  we only want to pass the pointer (that
4075                 // is already stored in the parameter, not the address of the pointer,
4076                 // and not the value of the variable).
4077                 //
4078                 public void EmitLoad (EmitContext ec)
4079                 {
4080                         ILGenerator ig = ec.ig;
4081                         int arg_idx = idx;
4082
4083                         if (!ec.MethodIsStatic)
4084                                 arg_idx++;
4085
4086
4087                         EmitLdArg (ig, arg_idx);
4088
4089                         //
4090                         // FIXME: Review for anonymous methods
4091                         //
4092                 }
4093
4094                 public override void Emit (EmitContext ec)
4095                 {
4096                         if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
4097                                 ec.EmitParameter (name);
4098                                 return;
4099                         }
4100
4101                         Emit (ec, false);
4102                 }
4103
4104                 public void Emit (EmitContext ec, bool leave_copy)
4105                 {
4106                         ILGenerator ig = ec.ig;
4107                         int arg_idx = idx;
4108
4109                         if (!ec.MethodIsStatic)
4110                                 arg_idx++;
4111
4112                         EmitLdArg (ig, arg_idx);
4113
4114                         if (is_ref) {
4115                                 if (prepared)
4116                                         ec.ig.Emit (OpCodes.Dup);
4117
4118                                 //
4119                                 // If we are a reference, we loaded on the stack a pointer
4120                                 // Now lets load the real value
4121                                 //
4122                                 LoadFromPtr (ig, type);
4123                         }
4124
4125                         if (leave_copy) {
4126                                 ec.ig.Emit (OpCodes.Dup);
4127
4128                                 if (is_ref) {
4129                                         temp = new LocalTemporary (ec, type);
4130                                         temp.Store (ec);
4131                                 }
4132                         }
4133                 }
4134
4135                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4136                 {
4137                         if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
4138                                 ec.EmitAssignParameter (name, source, leave_copy, prepare_for_load);
4139                                 return;
4140                         }
4141
4142                         ILGenerator ig = ec.ig;
4143                         int arg_idx = idx;
4144
4145                         prepared = prepare_for_load;
4146
4147                         if (!ec.MethodIsStatic)
4148                                 arg_idx++;
4149
4150                         if (is_ref && !prepared)
4151                                 EmitLdArg (ig, arg_idx);
4152
4153                         source.Emit (ec);
4154
4155                         if (leave_copy)
4156                                 ec.ig.Emit (OpCodes.Dup);
4157
4158                         if (is_ref) {
4159                                 if (leave_copy) {
4160                                         temp = new LocalTemporary (ec, type);
4161                                         temp.Store (ec);
4162                                 }
4163
4164                                 StoreFromPtr (ig, type);
4165
4166                                 if (temp != null)
4167                                         temp.Emit (ec);
4168                         } else {
4169                                 if (arg_idx <= 255)
4170                                         ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
4171                                 else
4172                                         ig.Emit (OpCodes.Starg, arg_idx);
4173                         }
4174                 }
4175
4176                 public void AddressOf (EmitContext ec, AddressOp mode)
4177                 {
4178                         if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
4179                                 ec.EmitAddressOfParameter (name);
4180                                 return;
4181                         }
4182
4183                         int arg_idx = idx;
4184
4185                         if (!ec.MethodIsStatic)
4186                                 arg_idx++;
4187
4188                         if (is_ref){
4189                                 if (arg_idx <= 255)
4190                                         ec.ig.Emit (OpCodes.Ldarg_S, (byte) arg_idx);
4191                                 else
4192                                         ec.ig.Emit (OpCodes.Ldarg, arg_idx);
4193                         } else {
4194                                 if (arg_idx <= 255)
4195                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
4196                                 else
4197                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
4198                         }
4199                 }
4200
4201         }
4202
4203         /// <summary>
4204         ///   Used for arguments to New(), Invocation()
4205         /// </summary>
4206         public class Argument {
4207                 public enum AType : byte {
4208                         Expression,
4209                         Ref,
4210                         Out,
4211                         ArgList
4212                 };
4213
4214                 public readonly AType ArgType;
4215                 public Expression Expr;
4216
4217                 public Argument (Expression expr, AType type)
4218                 {
4219                         this.Expr = expr;
4220                         this.ArgType = type;
4221                 }
4222
4223                 public Argument (Expression expr)
4224                 {
4225                         this.Expr = expr;
4226                         this.ArgType = AType.Expression;
4227                 }
4228
4229                 public Type Type {
4230                         get {
4231                                 if (ArgType == AType.Ref || ArgType == AType.Out)
4232                                         return TypeManager.GetReferenceType (Expr.Type);
4233                                 else
4234                                         return Expr.Type;
4235                         }
4236                 }
4237
4238                 public Parameter.Modifier Modifier
4239                 {
4240                         get {
4241                                 switch (ArgType) {
4242                                         case AType.Out:
4243                                                 return Parameter.Modifier.OUT | Parameter.Modifier.ISBYREF;
4244
4245                                         case AType.Ref:
4246                                                 return Parameter.Modifier.REF | Parameter.Modifier.ISBYREF;
4247
4248                                         default:
4249                                                 return Parameter.Modifier.NONE;
4250                                 }
4251                         }
4252                 }
4253
4254                 public static string FullDesc (Argument a)
4255                 {
4256                         if (a.ArgType == AType.ArgList)
4257                                 return "__arglist";
4258
4259                         return (a.ArgType == AType.Ref ? "ref " :
4260                                 (a.ArgType == AType.Out ? "out " : "")) +
4261                                 TypeManager.CSharpName (a.Expr.Type);
4262                 }
4263
4264                 public bool ResolveMethodGroup (EmitContext ec, Location loc)
4265                 {
4266                         SimpleName sn = Expr as SimpleName;
4267                         if (sn != null)
4268                                 Expr = sn.GetMethodGroup ();
4269
4270                         // FIXME: csc doesn't report any error if you try to use `ref' or
4271                         //        `out' in a delegate creation expression.
4272                         Expr = Expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
4273                         if (Expr == null)
4274                                 return false;
4275
4276                         return true;
4277                 }
4278
4279                 void Error_LValueRequired (Location loc)
4280                 {
4281                         Report.Error (1510, loc, "An lvalue is required as an argument to out or ref");
4282                 }
4283
4284                 public bool Resolve (EmitContext ec, Location loc)
4285                 {
4286                         bool old_do_flow_analysis = ec.DoFlowAnalysis;
4287                         ec.DoFlowAnalysis = true;
4288
4289                         if (ArgType == AType.Ref) {
4290                                 ec.InRefOutArgumentResolving = true;
4291                                 Expr = Expr.Resolve (ec);
4292                                 ec.InRefOutArgumentResolving = false;
4293                                 if (Expr == null) {
4294                                         ec.DoFlowAnalysis = old_do_flow_analysis;
4295                                         return false;
4296                                 }
4297
4298                                 Expr = Expr.DoResolveLValue (ec, Expr);
4299                                 if (Expr == null)
4300                                         Error_LValueRequired (loc);
4301                         } else if (ArgType == AType.Out) {
4302                                 ec.InRefOutArgumentResolving = true;
4303                                 Expr = Expr.DoResolveLValue (ec, EmptyExpression.Null);
4304                                 ec.InRefOutArgumentResolving = false;
4305
4306                                 if (Expr == null)
4307                                         Error_LValueRequired (loc);
4308                         }
4309                         else
4310                                 Expr = Expr.Resolve (ec);
4311
4312                         ec.DoFlowAnalysis = old_do_flow_analysis;
4313
4314                         if (Expr == null)
4315                                 return false;
4316
4317                         if (ArgType == AType.Expression)
4318                                 return true;
4319                         else {
4320                                 //
4321                                 // Catch errors where fields of a MarshalByRefObject are passed as ref or out
4322                                 // This is only allowed for `this'
4323                                 //
4324                                 FieldExpr fe = Expr as FieldExpr;
4325                                 if (fe != null && !fe.IsStatic){
4326                                         Expression instance = fe.InstanceExpression;
4327
4328                                         if (instance.GetType () != typeof (This)){
4329                                                 if (fe.InstanceExpression.Type.IsSubclassOf (TypeManager.mbr_type)){
4330                                                         Report.SymbolRelatedToPreviousError (fe.InstanceExpression.Type);
4331                                                         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",
4332                                                                 fe.Name);
4333                                                         return false;
4334                                                 }
4335                                         }
4336                                 }
4337                         }
4338
4339                         if (Expr.eclass != ExprClass.Variable){
4340                                 //
4341                                 // We just probe to match the CSC output
4342                                 //
4343                                 if (Expr.eclass == ExprClass.PropertyAccess ||
4344                                     Expr.eclass == ExprClass.IndexerAccess){
4345                                         Report.Error (
4346                                                 206, loc,
4347                                                 "A property or indexer can not be passed as an out or ref " +
4348                                                 "parameter");
4349                                 } else {
4350                                         Error_LValueRequired (loc);
4351                                 }
4352                                 return false;
4353                         }
4354
4355                         return true;
4356                 }
4357
4358                 public void Emit (EmitContext ec)
4359                 {
4360                         //
4361                         // Ref and Out parameters need to have their addresses taken.
4362                         //
4363                         // ParameterReferences might already be references, so we want
4364                         // to pass just the value
4365                         //
4366                         if (ArgType == AType.Ref || ArgType == AType.Out){
4367                                 AddressOp mode = AddressOp.Store;
4368
4369                                 if (ArgType == AType.Ref)
4370                                         mode |= AddressOp.Load;
4371
4372                                 if (Expr is ParameterReference){
4373                                         ParameterReference pr = (ParameterReference) Expr;
4374
4375                                         if (pr.IsRef)
4376                                                 pr.EmitLoad (ec);
4377                                         else {
4378
4379                                                 pr.AddressOf (ec, mode);
4380                                         }
4381                                 } else {
4382                                         if (Expr is IMemoryLocation)
4383                                                ((IMemoryLocation) Expr).AddressOf (ec, mode);
4384                                         else {
4385                                                 Report.Error (
4386                                                         1510, Expr.Location,
4387                                                         "An lvalue is required as an argument to out or ref");
4388                                                 return;
4389                                         }
4390                                 }
4391                         } else
4392                                 Expr.Emit (ec);
4393                 }
4394         }
4395
4396         /// <summary>
4397         ///   Invocation of methods or delegates.
4398         /// </summary>
4399         public class Invocation : ExpressionStatement {
4400                 public readonly ArrayList Arguments;
4401
4402                 Expression expr;
4403                 MethodBase method = null;
4404
4405                 //
4406                 // arguments is an ArrayList, but we do not want to typecast,
4407                 // as it might be null.
4408                 //
4409                 // FIXME: only allow expr to be a method invocation or a
4410                 // delegate invocation (7.5.5)
4411                 //
4412                 public Invocation (Expression expr, ArrayList arguments, Location l)
4413                 {
4414                         this.expr = expr;
4415                         Arguments = arguments;
4416                         loc = l;
4417                 }
4418
4419                 public Expression Expr {
4420                         get {
4421                                 return expr;
4422                         }
4423                 }
4424
4425                 /// <summary>
4426                 ///   Determines "better conversion" as specified in 7.4.2.3
4427                 ///
4428                 ///    Returns : p    if a->p is better,
4429                 ///              q    if a->q is better,
4430                 ///              null if neither is better
4431                 /// </summary>
4432                 static Type BetterConversion (EmitContext ec, Argument a, Type p, Type q, Location loc)
4433                 {
4434                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
4435                         Expression argument_expr = a.Expr;
4436
4437                         // p = TypeManager.TypeToCoreType (p);
4438                         // q = TypeManager.TypeToCoreType (q);
4439
4440                         if (argument_type == null)
4441                                 throw new Exception ("Expression of type " + a.Expr +
4442                                                      " does not resolve its type");
4443
4444                         if (p == null || q == null)
4445                                 throw new InternalErrorException ("BetterConversion Got a null conversion");
4446
4447                         if (p == q)
4448                                 return null;
4449
4450                         if (argument_expr is NullLiteral) {
4451                         //
4452                                 // If the argument is null and one of the types to compare is 'object' and
4453                                 // the other is a reference type, we prefer the other.
4454                         //
4455                                 // This follows from the usual rules:
4456                                 //   * There is an implicit conversion from 'null' to type 'object'
4457                                 //   * There is an implicit conversion from 'null' to any reference type
4458                                 //   * There is an implicit conversion from any reference type to type 'object'
4459                                 //   * There is no implicit conversion from type 'object' to other reference types
4460                                 //  => Conversion of 'null' to a reference type is better than conversion to 'object'
4461                                 //
4462                                 //  FIXME: This probably isn't necessary, since the type of a NullLiteral is the
4463                                 //         null type. I think it used to be 'object' and thus needed a special
4464                                 //         case to avoid the immediately following two checks.
4465                                 //
4466                                 if (!p.IsValueType && q == TypeManager.object_type)
4467                                         return p;
4468                                 if (!q.IsValueType && p == TypeManager.object_type)
4469                                         return q;
4470                         }
4471
4472                         if (argument_type == p)
4473                                 return p;
4474
4475                         if (argument_type == q)
4476                                 return q;
4477
4478                         Expression p_tmp = new EmptyExpression (p);
4479                         Expression q_tmp = new EmptyExpression (q);
4480
4481                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
4482                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
4483
4484                         if (p_to_q && !q_to_p)
4485                                 return p;
4486
4487                         if (q_to_p && !p_to_q)
4488                                 return q;
4489
4490                         if (p == TypeManager.sbyte_type)
4491                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
4492                                     q == TypeManager.uint32_type || q == TypeManager.uint64_type)
4493                                         return p;
4494                         if (q == TypeManager.sbyte_type)
4495                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
4496                                     p == TypeManager.uint32_type || p == TypeManager.uint64_type)
4497                                         return q;
4498
4499                         if (p == TypeManager.short_type)
4500                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
4501                                     q == TypeManager.uint64_type)
4502                                         return p;
4503
4504                         if (q == TypeManager.short_type)
4505                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
4506                                     p == TypeManager.uint64_type)
4507                                         return q;
4508
4509                         if (p == TypeManager.int32_type)
4510                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
4511                                         return p;
4512
4513                         if (q == TypeManager.int32_type)
4514                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
4515                                         return q;
4516
4517                         if (p == TypeManager.int64_type)
4518                                 if (q == TypeManager.uint64_type)
4519                                         return p;
4520                         if (q == TypeManager.int64_type)
4521                                 if (p == TypeManager.uint64_type)
4522                                         return q;
4523
4524                         return null;
4525                 }
4526
4527                 /// <summary>
4528                 ///   Determines "Better function" between candidate
4529                 ///   and the current best match
4530                 /// </summary>
4531                 /// <remarks>
4532                 ///    Returns a boolean indicating :
4533                 ///     false if candidate ain't better
4534                 ///     true  if candidate is better than the current best match
4535                 /// </remarks>
4536                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
4537                                            MethodBase candidate, bool candidate_params,
4538                                            MethodBase best, bool best_params, Location loc)
4539                 {
4540                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
4541                         ParameterData best_pd = TypeManager.GetParameterData (best);
4542
4543                         bool better_at_least_one = false;
4544                         bool same = true;
4545                         for (int j = 0; j < argument_count; ++j) {
4546                                 Argument a = (Argument) args [j];
4547
4548                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (j));
4549                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (j));
4550
4551                                 if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
4552                                         if (candidate_params)
4553                                                 ct = TypeManager.GetElementType (ct);
4554
4555                                 if (best_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
4556                                         if (best_params)
4557                                                 bt = TypeManager.GetElementType (bt);
4558
4559                                 if (ct.Equals (bt))
4560                                         continue;
4561
4562                                 same = false;
4563                                 Type better = BetterConversion (ec, a, ct, bt, loc);
4564                                 // for each argument, the conversion to 'ct' should be no worse than
4565                                 // the conversion to 'bt'.
4566                                 if (better == bt)
4567                                         return false;
4568
4569                                 // for at least one argument, the conversion to 'ct' should be better than
4570                                 // the conversion to 'bt'.
4571                                 if (better == ct)
4572                                         better_at_least_one = true;
4573                         }
4574
4575                         if (better_at_least_one)
4576                                 return true;
4577
4578                         if (!same)
4579                                 return false;
4580
4581                         //
4582                         // If two methods have equal parameter types, but
4583                         // only one of them is generic, the non-generic one wins.
4584                         //
4585                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
4586                                 return true;
4587                         else if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
4588                                 return false;
4589
4590                         //
4591                         // Note that this is not just an optimization.  This handles the case
4592                         // This handles the case
4593                         //
4594                         //   Add (float f1, float f2, float f3);
4595                         //   Add (params decimal [] foo);
4596                         //
4597                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
4598                         // first candidate would've chosen as better.
4599                         //
4600                         //
4601                         // This handles the following cases:
4602                         //
4603                         //   Trim () is better than Trim (params char[] chars)
4604                         //   Concat (string s1, string s2, string s3) is better than
4605                         //     Concat (string s1, params string [] srest)
4606                         //
4607                         return !candidate_params && best_params;
4608                 }
4609
4610                 static bool IsOverride (MethodBase cand_method, MethodBase base_method)
4611                 {
4612                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
4613                                 return false;
4614
4615                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
4616                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
4617
4618                         if (cand_pd.Count != base_pd.Count)
4619                                 return false;
4620
4621                         for (int j = 0; j < cand_pd.Count; ++j) {
4622                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
4623                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
4624                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
4625                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
4626
4627                                 if (cm != bm || ct != bt)
4628                                         return false;
4629                         }
4630
4631                         return true;
4632                 }
4633
4634                 public static string FullMethodDesc (MethodBase mb)
4635                 {
4636                         string ret_type = "";
4637
4638                         if (mb == null)
4639                                 return "";
4640
4641                         if (mb is MethodInfo)
4642                                 ret_type = TypeManager.CSharpName (((MethodInfo) mb).ReturnType);
4643
4644                         StringBuilder sb = new StringBuilder (ret_type);
4645                         sb.Append (" ");
4646                         sb.Append (mb.ReflectedType.ToString ());
4647                         sb.Append (".");
4648                         sb.Append (mb.Name);
4649
4650                         ParameterData pd = TypeManager.GetParameterData (mb);
4651
4652                         int count = pd.Count;
4653                         sb.Append (" (");
4654
4655                         for (int i = count; i > 0; ) {
4656                                 i--;
4657
4658                                 sb.Append (pd.ParameterDesc (count - i - 1));
4659                                 if (i != 0)
4660                                         sb.Append (", ");
4661                         }
4662
4663                         sb.Append (")");
4664                         return sb.ToString ();
4665                 }
4666
4667                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
4668                 {
4669                         MemberInfo [] miset;
4670                         MethodGroupExpr union;
4671
4672                         if (mg1 == null) {
4673                                 if (mg2 == null)
4674                                         return null;
4675                                 return (MethodGroupExpr) mg2;
4676                         } else {
4677                                 if (mg2 == null)
4678                                         return (MethodGroupExpr) mg1;
4679                         }
4680
4681                         MethodGroupExpr left_set = null, right_set = null;
4682                         int length1 = 0, length2 = 0;
4683
4684                         left_set = (MethodGroupExpr) mg1;
4685                         length1 = left_set.Methods.Length;
4686
4687                         right_set = (MethodGroupExpr) mg2;
4688                         length2 = right_set.Methods.Length;
4689
4690                         ArrayList common = new ArrayList ();
4691
4692                         foreach (MethodBase r in right_set.Methods){
4693                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
4694                                         common.Add (r);
4695                         }
4696
4697                         miset = new MemberInfo [length1 + length2 - common.Count];
4698                         left_set.Methods.CopyTo (miset, 0);
4699
4700                         int k = length1;
4701
4702                         foreach (MethodBase r in right_set.Methods) {
4703                                 if (!common.Contains (r))
4704                                         miset [k++] = r;
4705                         }
4706
4707                         union = new MethodGroupExpr (miset, loc);
4708
4709                         return union;
4710                 }
4711
4712                 public static bool IsParamsMethodApplicable (EmitContext ec, MethodGroupExpr me,
4713                                                              ArrayList arguments, int arg_count,
4714                                                              ref MethodBase candidate)
4715                 {
4716                         return IsParamsMethodApplicable (
4717                                 ec, me, arguments, arg_count, false, ref candidate) ||
4718                                 IsParamsMethodApplicable (
4719                                         ec, me, arguments, arg_count, true, ref candidate);
4720
4721
4722                 }
4723
4724                 static bool IsParamsMethodApplicable (EmitContext ec, MethodGroupExpr me,
4725                                                       ArrayList arguments, int arg_count,
4726                                                       bool do_varargs, ref MethodBase candidate)
4727                 {
4728                         if (!me.HasTypeArguments &&
4729                             !TypeManager.InferParamsTypeArguments (ec, arguments, ref candidate))
4730                                 return false;
4731
4732                         return IsParamsMethodApplicable (
4733                                 ec, arguments, arg_count, candidate, do_varargs);
4734                 }
4735
4736                 /// <summary>
4737                 ///   Determines if the candidate method, if a params method, is applicable
4738                 ///   in its expanded form to the given set of arguments
4739                 /// </summary>
4740                 static bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments,
4741                                                       int arg_count, MethodBase candidate,
4742                                                       bool do_varargs)
4743                 {
4744                         ParameterData pd = TypeManager.GetParameterData (candidate);
4745
4746                         int pd_count = pd.Count;
4747
4748                         if (pd_count == 0)
4749                                 return false;
4750
4751                         int count = pd_count - 1;
4752                         if (do_varargs) {
4753                                 if (pd.ParameterModifier (count) != Parameter.Modifier.ARGLIST)
4754                                         return false;
4755                                 if (pd_count != arg_count)
4756                                         return false;
4757                         } else {
4758                                 if (pd.ParameterModifier (count) != Parameter.Modifier.PARAMS)
4759                                 return false;
4760                         }
4761
4762                         if (count > arg_count)
4763                                 return false;
4764
4765                         if (pd_count == 1 && arg_count == 0)
4766                                 return true;
4767
4768                         //
4769                         // If we have come this far, the case which
4770                         // remains is when the number of parameters is
4771                         // less than or equal to the argument count.
4772                         //
4773                         for (int i = 0; i < count; ++i) {
4774
4775                                 Argument a = (Argument) arguments [i];
4776
4777                                 Parameter.Modifier a_mod = a.Modifier &
4778                                         (unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF)));
4779                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
4780                                         (unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF)));
4781
4782                                 if (a_mod == p_mod) {
4783
4784                                         if (a_mod == Parameter.Modifier.NONE)
4785                                                 if (!Convert.ImplicitConversionExists (ec,
4786                                                                                        a.Expr,
4787                                                                                        pd.ParameterType (i)))
4788                                                         return false;
4789
4790                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
4791                                                 Type pt = pd.ParameterType (i);
4792
4793                                                 if (!pt.IsByRef)
4794                                                         pt = TypeManager.GetReferenceType (pt);
4795
4796                                                 if (pt != a.Type)
4797                                                         return false;
4798                                         }
4799                                 } else
4800                                         return false;
4801
4802                         }
4803
4804                         if (do_varargs) {
4805                                 Argument a = (Argument) arguments [count];
4806                                 if (!(a.Expr is Arglist))
4807                                         return false;
4808
4809                                 return true;
4810                         }
4811
4812                         Type element_type = TypeManager.GetElementType (pd.ParameterType (pd_count - 1));
4813
4814                         for (int i = pd_count - 1; i < arg_count; i++) {
4815                                 Argument a = (Argument) arguments [i];
4816
4817                                 if (!Convert.ImplicitConversionExists (ec, a.Expr, element_type))
4818                                         return false;
4819                         }
4820
4821                         return true;
4822                 }
4823
4824                 public static bool IsApplicable (EmitContext ec, MethodGroupExpr me,
4825                                                  ArrayList arguments, int arg_count,
4826                                                  ref MethodBase candidate)
4827                 {
4828                         if (!me.HasTypeArguments &&
4829                             !TypeManager.InferTypeArguments (ec, arguments, ref candidate))
4830                                 return false;
4831
4832                         return IsApplicable (ec, arguments, arg_count, candidate);
4833                 }
4834
4835                 /// <summary>
4836                 ///   Determines if the candidate method is applicable (section 14.4.2.1)
4837                 ///   to the given set of arguments
4838                 /// </summary>
4839                 static bool IsApplicable (EmitContext ec, ArrayList arguments, int arg_count,
4840                                           MethodBase candidate)
4841                 {
4842                         ParameterData pd = TypeManager.GetParameterData (candidate);
4843
4844                         if (arg_count != pd.Count)
4845                                 return false;
4846
4847                         for (int i = arg_count; i > 0; ) {
4848                                 i--;
4849
4850                                 Argument a = (Argument) arguments [i];
4851
4852                                 Parameter.Modifier a_mod = a.Modifier &
4853                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
4854                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
4855                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
4856
4857
4858                                 if (a_mod == p_mod ||
4859                                     (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
4860                                         if (a_mod == Parameter.Modifier.NONE) {
4861                                                 if (!Convert.ImplicitConversionExists (ec,
4862                                                                                        a.Expr,
4863                                                                                        pd.ParameterType (i)))
4864                                                         return false;
4865                                         }
4866
4867                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
4868                                                 Type pt = pd.ParameterType (i);
4869
4870                                                 if (!pt.IsByRef)
4871                                                         pt = TypeManager.GetReferenceType (pt);
4872
4873                                                 if (pt != a.Type)
4874                                                         return false;
4875                                         }
4876                                 } else
4877                                         return false;
4878                         }
4879
4880                         return true;
4881                 }
4882
4883                 static private bool IsAncestralType (Type first_type, Type second_type)
4884                 {
4885                         return first_type != second_type &&
4886                                 (second_type.IsSubclassOf (first_type) ||
4887                                  TypeManager.ImplementsInterface (second_type, first_type));
4888                 }
4889
4890                 /// <summary>
4891                 ///   Find the Applicable Function Members (7.4.2.1)
4892                 ///
4893                 ///   me: Method Group expression with the members to select.
4894                 ///       it might contain constructors or methods (or anything
4895                 ///       that maps to a method).
4896                 ///
4897                 ///   Arguments: ArrayList containing resolved Argument objects.
4898                 ///
4899                 ///   loc: The location if we want an error to be reported, or a Null
4900                 ///        location for "probing" purposes.
4901                 ///
4902                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4903                 ///            that is the best match of me on Arguments.
4904                 ///
4905                 /// </summary>
4906                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
4907                                                           ArrayList Arguments, bool may_fail,
4908                                                           Location loc)
4909                 {
4910                         MethodBase method = null;
4911                         bool method_params = false;
4912                         Type applicable_type = null;
4913                         int arg_count = 0;
4914                         ArrayList candidates = new ArrayList (2);
4915                         ArrayList candidate_overrides = null;
4916
4917                         //
4918                         // Used to keep a map between the candidate
4919                         // and whether it is being considered in its
4920                         // normal or expanded form
4921                         //
4922                         // false is normal form, true is expanded form
4923                         //
4924                         Hashtable candidate_to_form = null;
4925
4926                         if (Arguments != null)
4927                                 arg_count = Arguments.Count;
4928
4929                         if ((me.Name == "Invoke") &&
4930                             TypeManager.IsDelegateType (me.DeclaringType)) {
4931                                 Error_InvokeOnDelegate (loc);
4932                                 return null;
4933                         }
4934
4935                         MethodBase[] methods = me.Methods;
4936
4937                         //
4938                         // First we construct the set of applicable methods
4939                         //
4940                         bool is_sorted = true;
4941                         for (int i = 0; i < methods.Length; i++){
4942                                 Type decl_type = methods [i].DeclaringType;
4943
4944                                 //
4945                                 // If we have already found an applicable method
4946                                 // we eliminate all base types (Section 14.5.5.1)
4947                                 //
4948                                 if ((applicable_type != null) &&
4949                                     IsAncestralType (decl_type, applicable_type))
4950                                         continue;
4951
4952                                 //
4953                                 // Methods marked 'override' don't take part in 'applicable_type'
4954                                 // computation, nor in the actual overload resolution.
4955                                 // However, they still need to be emitted instead of a base virtual method.
4956                                 // We avoid doing the 'applicable' test here, since it'll anyway be applied
4957                                 // to the base virtual function, and IsOverride is much faster than IsApplicable.
4958                                 //
4959                                 if (!me.IsBase && TypeManager.IsOverride (methods [i])) {
4960                                         if (candidate_overrides == null)
4961                                                 candidate_overrides = new ArrayList ();
4962                                         candidate_overrides.Add (methods [i]);
4963                                         continue;
4964                                 }
4965
4966                                 //
4967                                 // Check if candidate is applicable (section 14.4.2.1)
4968                                 //   Is candidate applicable in normal form?
4969                                 //
4970                                 bool is_applicable = IsApplicable (
4971                                         ec, me, Arguments, arg_count, ref methods [i]);
4972
4973                                 if (!is_applicable &&
4974                                     (IsParamsMethodApplicable (
4975                                             ec, me, Arguments, arg_count, ref methods [i]))) {
4976                                         MethodBase candidate = methods [i];
4977                                         if (candidate_to_form == null)
4978                                                 candidate_to_form = new PtrHashtable ();
4979                                         candidate_to_form [candidate] = candidate;
4980                                         // Candidate is applicable in expanded form
4981                                         is_applicable = true;
4982                                 }
4983
4984                                 if (!is_applicable)
4985                                         continue;
4986
4987                                 candidates.Add (methods [i]);
4988
4989                                 if (applicable_type == null)
4990                                         applicable_type = decl_type;
4991                                 else if (applicable_type != decl_type) {
4992                                         is_sorted = false;
4993                                         if (IsAncestralType (applicable_type, decl_type))
4994                                                 applicable_type = decl_type;
4995                                 }
4996                         }
4997
4998                         int candidate_top = candidates.Count;
4999
5000                         if (applicable_type == null) {
5001                                 //
5002                                 // Okay so we have failed to find anything so we
5003                                 // return by providing info about the closest match
5004                                 //
5005                                 for (int i = 0; i < methods.Length; ++i) {
5006                                         MethodBase c = (MethodBase) methods [i];
5007                                         ParameterData pd = TypeManager.GetParameterData (c);
5008
5009                                         if (pd.Count != arg_count)
5010                                                 continue;
5011
5012                                         if (!TypeManager.InferTypeArguments (ec, Arguments, ref c))
5013                                                 continue;
5014
5015                                         VerifyArgumentsCompat (ec, Arguments, arg_count,
5016                                                                c, false, null, may_fail, loc);
5017                                         break;
5018                                 }
5019
5020                                 if (!may_fail) {
5021                                         string report_name = me.Name;
5022                                         if (report_name == ".ctor")
5023                                                 report_name = me.DeclaringType.ToString ();
5024
5025                                         for (int i = 0; i < methods.Length; ++i) {
5026                                                 MethodBase c = methods [i];
5027                                                 ParameterData pd = TypeManager.GetParameterData (c);
5028
5029                                                 if (pd.Count != arg_count)
5030                                                         continue;
5031
5032                                                 if (TypeManager.InferTypeArguments (ec, Arguments, ref c))
5033                                                         continue;
5034
5035                                                 Report.Error (
5036                                                         411, loc, "The type arguments for " +
5037                                                         "method `{0}' cannot be infered from " +
5038                                                         "the usage. Try specifying the type " +
5039                                                         "arguments explicitly.", report_name);
5040                                                 return null;
5041                                         }
5042
5043                                         Error_WrongNumArguments (
5044                                                 loc, report_name, arg_count);
5045                                         return null;
5046                                 }
5047
5048                                 return null;
5049                         }
5050
5051                         if (!is_sorted) {
5052                                 //
5053                                 // At this point, applicable_type is _one_ of the most derived types
5054                                 // in the set of types containing the methods in this MethodGroup.
5055                                 // Filter the candidates so that they only contain methods from the
5056                                 // most derived types.
5057                                 //
5058
5059                                 int finalized = 0; // Number of finalized candidates
5060
5061                                 do {
5062                                         // Invariant: applicable_type is a most derived type
5063
5064                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
5065                                         // eliminating all it's base types.  At the same time, we'll also move
5066                                         // every unrelated type to the end of the array, and pick the next
5067                                         // 'applicable_type'.
5068
5069                                         Type next_applicable_type = null;
5070                                         int j = finalized; // where to put the next finalized candidate
5071                                         int k = finalized; // where to put the next undiscarded candidate
5072                                         for (int i = finalized; i < candidate_top; ++i) {
5073                                                 MethodBase candidate = (MethodBase) candidates [i];
5074                                                 Type decl_type = candidate.DeclaringType;
5075
5076                                                 if (decl_type == applicable_type) {
5077                                                         candidates [k++] = candidates [j];
5078                                                         candidates [j++] = candidates [i];
5079                                                         continue;
5080                                                 }
5081
5082                                                 if (IsAncestralType (decl_type, applicable_type))
5083                                                         continue;
5084
5085                                                 if (next_applicable_type != null &&
5086                                                     IsAncestralType (decl_type, next_applicable_type))
5087                                                         continue;
5088
5089                                                 candidates [k++] = candidates [i];
5090
5091                                                 if (next_applicable_type == null ||
5092                                                     IsAncestralType (next_applicable_type, decl_type))
5093                                                         next_applicable_type = decl_type;
5094                                         }
5095
5096                                         applicable_type = next_applicable_type;
5097                                         finalized = j;
5098                                         candidate_top = k;
5099                                 } while (applicable_type != null);
5100                         }
5101
5102                         //
5103                         // Now we actually find the best method
5104                         //
5105
5106                         method = (MethodBase) candidates [0];
5107                         method_params = candidate_to_form != null && candidate_to_form.Contains (method);
5108                         for (int ix = 1; ix < candidate_top; ix++){
5109                                 MethodBase candidate = (MethodBase) candidates [ix];
5110
5111                                 if (candidate == method)
5112                                         continue;
5113
5114                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
5115
5116                                 if (BetterFunction (ec, Arguments, arg_count,
5117                                                     candidate, cand_params,
5118                                                     method, method_params, loc)) {
5119                                         method = candidate;
5120                                         method_params = cand_params;
5121                                 }
5122                         }
5123
5124                         //
5125                         // Now check that there are no ambiguities i.e the selected method
5126                         // should be better than all the others
5127                         //
5128                         bool ambiguous = false;
5129                         for (int ix = 0; ix < candidate_top; ix++){
5130                                 MethodBase candidate = (MethodBase) candidates [ix];
5131
5132                                 if (candidate == method)
5133                                         continue;
5134
5135                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
5136                                 if (!BetterFunction (ec, Arguments, arg_count,
5137                                                     method, method_params,
5138                                                     candidate, cand_params,
5139                                                      loc)) {
5140                                         Report.SymbolRelatedToPreviousError (candidate);
5141                                         ambiguous = true;
5142                                 }
5143                         }
5144
5145                         if (ambiguous) {
5146                                 Report.SymbolRelatedToPreviousError (method);
5147                                 Report.Error (121, loc, "Ambiguous call when selecting function due to implicit casts");
5148                                 return null;
5149                         }
5150
5151                         //
5152                         // If the method is a virtual function, pick an override closer to the LHS type.
5153                         //
5154                         if (!me.IsBase && method.IsVirtual) {
5155                                 if (TypeManager.IsOverride (method))
5156                                         throw new InternalErrorException (
5157                                                 "Should not happen.  An 'override' method took part in overload resolution: " + method);
5158
5159                                 if (candidate_overrides != null)
5160                                         foreach (MethodBase candidate in candidate_overrides) {
5161                                                 if (IsOverride (candidate, method))
5162                                                         method = candidate;
5163                                         }
5164                         }
5165
5166                         //
5167                         // And now check if the arguments are all
5168                         // compatible, perform conversions if
5169                         // necessary etc. and return if everything is
5170                         // all right
5171                         //
5172                         if (!VerifyArgumentsCompat (ec, Arguments, arg_count, method,
5173                                                     method_params, null, may_fail, loc))
5174                                 return null;
5175
5176                         if (method != null) {
5177                                 IMethodData data = TypeManager.GetMethod (method);
5178                                 if (data != null)
5179                                         data.SetMemberIsUsed ();
5180                         }
5181                         return method;
5182                 }
5183
5184                 static void Error_WrongNumArguments (Location loc, String name, int arg_count)
5185                 {
5186                         if (name == "Finalize" && arg_count == 0) {
5187                                 Report.Error (245, loc, "Destructors and object.Finalize cannot be called directly. Consider calling IDisposable.Dispose if available");
5188                         }
5189                         else {
5190                                 Report.Error (1501, loc,
5191                                         "No overload for method `" + name + "' takes `" +
5192                                         arg_count + "' arguments");
5193                         }
5194                 }
5195
5196                 static void Error_InvokeOnDelegate (Location loc)
5197                 {
5198                         Report.Error (1533, loc,
5199                                       "Invoke cannot be called directly on a delegate");
5200                 }
5201
5202                 static void Error_InvalidArguments (Location loc, int idx, MethodBase method,
5203                                                     Type delegate_type, Argument a, ParameterData expected_par)
5204                 {
5205                         if (delegate_type == null)
5206                                 Report.Error (1502, loc, "The best overloaded match for method '{0}' has some invalid arguments",
5207                                               TypeManager.CSharpSignature (method));
5208                         else
5209                                 Report.Error (1594, loc,
5210                                               "Delegate '" + delegate_type.ToString () +
5211                                               "' has some invalid arguments.");
5212
5213                         string par_desc = expected_par.ParameterDesc (idx);
5214
5215                         if (a.Modifier != expected_par.ParameterModifier (idx)) {
5216                                 if ((expected_par.ParameterModifier (idx) & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) == 0)
5217                                         Report.Error (1615, loc, "Argument '{0}' should not be passed with the '{1}' keyword",
5218                                                 idx + 1, Parameter.GetModifierSignature (a.Modifier));
5219                                 else
5220                                         Report.Error (1620, loc, "Argument '{0}' must be passed with the '{1}' keyword",
5221                                                 idx + 1, Parameter.GetModifierSignature (expected_par.ParameterModifier (idx)));
5222                                 return;
5223                         }
5224
5225                         Report.Error (1503, loc,
5226                                       String.Format ("Argument {0}: Cannot convert from '{1}' to '{2}'",
5227                                                      idx + 1, Argument.FullDesc (a), par_desc));
5228                 }
5229
5230                 public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
5231                                                           int arg_count, MethodBase method,
5232                                                           bool chose_params_expanded,
5233                                                           Type delegate_type, bool may_fail,
5234                                                           Location loc)
5235                 {
5236                         ParameterData pd = TypeManager.GetParameterData (method);
5237                         int pd_count = pd.Count;
5238
5239                         for (int j = 0; j < arg_count; j++) {
5240                                 Argument a = (Argument) Arguments [j];
5241                                 Expression a_expr = a.Expr;
5242                                 Type parameter_type = pd.ParameterType (j);
5243                                 Parameter.Modifier pm = pd.ParameterModifier (j);
5244
5245                                 if (pm == Parameter.Modifier.PARAMS){
5246                                         if ((pm & ~Parameter.Modifier.PARAMS) != a.Modifier) {
5247                                                 if (!may_fail)
5248                                                         Error_InvalidArguments (
5249                                                                 loc, j, method, delegate_type,
5250                                                                 a, pd);
5251                                                 return false;
5252                                         }
5253
5254                                         if (chose_params_expanded)
5255                                                 parameter_type = TypeManager.GetElementType (parameter_type);
5256                                 } else if (pm == Parameter.Modifier.ARGLIST){
5257                                         continue;
5258                                 } else {
5259                                         //
5260                                         // Check modifiers
5261                                         //
5262                                         if (pd.ParameterModifier (j) != a.Modifier){
5263                                                 if (!may_fail)
5264                                                         Error_InvalidArguments (
5265                                                                 loc, j, method, delegate_type,
5266                                                                 a, pd);
5267                                                 return false;
5268                                         }
5269                                 }
5270
5271                                 //
5272                                 // Check Type
5273                                 //
5274                                 if (!TypeManager.IsEqual (a.Type, parameter_type)){
5275                                         Expression conv;
5276
5277                                         conv = Convert.ImplicitConversion (ec, a_expr, parameter_type, loc);
5278
5279                                         if (conv == null) {
5280                                                 if (!may_fail)
5281                                                         Error_InvalidArguments (loc, j, method, delegate_type, a, pd);
5282                                                 return false;
5283                                         }
5284
5285                                         //
5286                                         // Update the argument with the implicit conversion
5287                                         //
5288                                         if (a_expr != conv)
5289                                                 a.Expr = conv;
5290                                 }
5291
5292                                 if (parameter_type.IsPointer){
5293                                         if (!ec.InUnsafe){
5294                                                 UnsafeError (loc);
5295                                                 return false;
5296                                         }
5297                                 }
5298
5299                                 Parameter.Modifier a_mod = a.Modifier &
5300                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
5301                                 Parameter.Modifier p_mod = pd.ParameterModifier (j) &
5302                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
5303
5304                                 if (a_mod != p_mod &&
5305                                     pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
5306                                         if (!may_fail) {
5307                                                 Report.Error (1502, loc,
5308                                                        "The best overloaded match for method '" + FullMethodDesc (method)+
5309                                                        "' has some invalid arguments");
5310                                                 Report.Error (1503, loc,
5311                                                        "Argument " + (j+1) +
5312                                                        ": Cannot convert from '" + Argument.FullDesc (a)
5313                                                        + "' to '" + pd.ParameterDesc (j) + "'");
5314                                         }
5315
5316                                         return false;
5317                                 }
5318                         }
5319
5320                         return true;
5321                 }
5322
5323                 public override Expression DoResolve (EmitContext ec)
5324                 {
5325                         //
5326                         // First, resolve the expression that is used to
5327                         // trigger the invocation
5328                         //
5329                         SimpleName sn = expr as SimpleName;
5330                         if (sn != null)
5331                                 expr = sn.GetMethodGroup ();
5332
5333                         expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
5334                         if (expr == null)
5335                                 return null;
5336
5337                         if (!(expr is MethodGroupExpr)) {
5338                                 Type expr_type = expr.Type;
5339
5340                                 if (expr_type != null){
5341                                         bool IsDelegate = TypeManager.IsDelegateType (expr_type);
5342                                         if (IsDelegate)
5343                                                 return (new DelegateInvocation (
5344                                                         this.expr, Arguments, loc)).Resolve (ec);
5345                                 }
5346                         }
5347
5348                         if (!(expr is MethodGroupExpr)){
5349                                 expr.Error_UnexpectedKind (ResolveFlags.MethodGroup, loc);
5350                                 return null;
5351                         }
5352
5353                         //
5354                         // Next, evaluate all the expressions in the argument list
5355                         //
5356                         if (Arguments != null){
5357                                 foreach (Argument a in Arguments){
5358                                         if (!a.Resolve (ec, loc))
5359                                                 return null;
5360                                 }
5361                         }
5362
5363                         MethodGroupExpr mg = (MethodGroupExpr) expr;
5364                         method = OverloadResolve (ec, mg, Arguments, false, loc);
5365
5366                         if (method == null)
5367                                 return null;
5368
5369                         MethodInfo mi = method as MethodInfo;
5370                         if (mi != null) {
5371                                 type = TypeManager.TypeToCoreType (mi.ReturnType);
5372                                 Expression iexpr = mg.InstanceExpression;
5373                                 if (mi.IsStatic) {
5374                                         if (iexpr == null ||
5375                                             iexpr is This || iexpr is EmptyExpression ||
5376                                             mg.IdenticalTypeName) {
5377                                                 mg.InstanceExpression = null;
5378                                         } else {
5379                                                 MemberExpr.error176 (loc, mi.Name);
5380                                                 return null;
5381                                         }
5382                                 } else {
5383                                         if (iexpr == null || iexpr is EmptyExpression) {
5384                                                 SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
5385                                                 return null;
5386                                         }
5387                                 }
5388                         }
5389
5390                         if (type.IsPointer){
5391                                 if (!ec.InUnsafe){
5392                                         UnsafeError (loc);
5393                                         return null;
5394                                 }
5395                         }
5396
5397                         //
5398                         // Only base will allow this invocation to happen.
5399                         //
5400                         if (mg.IsBase && method.IsAbstract){
5401                                 Report.Error (205, loc, "Cannot call an abstract base member: " +
5402                                               FullMethodDesc (method));
5403                                 return null;
5404                         }
5405
5406                         if (method.Name == "Finalize" && Arguments == null) {
5407                                 Report.Error (250, loc, "Do not directly call your base class Finalize method. It is called automatically from your destructor");
5408                                 return null;
5409                         }
5410
5411                         if ((method.Attributes & MethodAttributes.SpecialName) != 0){
5412                                 if (TypeManager.LookupDeclSpace (method.DeclaringType) != null || TypeManager.IsSpecialMethod (method)) {
5413                                         Report.Error (571, loc, TypeManager.CSharpSignature (method) + ": can not call operator or accessor");
5414                                         return null;
5415                                 }
5416                         }
5417
5418                         if (mg.InstanceExpression != null)
5419                                 mg.InstanceExpression.CheckMarshallByRefAccess (ec.ContainerType);
5420
5421                         eclass = ExprClass.Value;
5422                         return this;
5423                 }
5424
5425                 // <summary>
5426                 //   Emits the list of arguments as an array
5427                 // </summary>
5428                 static void EmitParams (EmitContext ec, int idx, ArrayList arguments)
5429                 {
5430                         ILGenerator ig = ec.ig;
5431                         int count = arguments.Count - idx;
5432                         Argument a = (Argument) arguments [idx];
5433                         Type t = a.Expr.Type;
5434
5435                         IntConstant.EmitInt (ig, count);
5436                         ig.Emit (OpCodes.Newarr, TypeManager.TypeToCoreType (t));
5437
5438                         int top = arguments.Count;
5439                         for (int j = idx; j < top; j++){
5440                                 a = (Argument) arguments [j];
5441
5442                                 ig.Emit (OpCodes.Dup);
5443                                 IntConstant.EmitInt (ig, j - idx);
5444
5445                                 bool is_stobj, has_type_arg;
5446                                 OpCode op = ArrayAccess.GetStoreOpcode (t, out is_stobj, out has_type_arg);
5447                                 if (is_stobj)
5448                                         ig.Emit (OpCodes.Ldelema, t);
5449
5450                                 a.Emit (ec);
5451
5452                                 if (has_type_arg)
5453                                         ig.Emit (op, t);
5454                                 else
5455                                         ig.Emit (op);
5456                         }
5457                 }
5458
5459                 /// <summary>
5460                 ///   Emits a list of resolved Arguments that are in the arguments
5461                 ///   ArrayList.
5462                 ///
5463                 ///   The MethodBase argument might be null if the
5464                 ///   emission of the arguments is known not to contain
5465                 ///   a `params' field (for example in constructors or other routines
5466                 ///   that keep their arguments in this structure)
5467                 ///
5468                 ///   if `dup_args' is true, a copy of the arguments will be left
5469                 ///   on the stack. If `dup_args' is true, you can specify `this_arg'
5470                 ///   which will be duplicated before any other args. Only EmitCall
5471                 ///   should be using this interface.
5472                 /// </summary>
5473                 public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments, bool dup_args, LocalTemporary this_arg)
5474                 {
5475                         ParameterData pd;
5476                         if (mb != null)
5477                                 pd = TypeManager.GetParameterData (mb);
5478                         else
5479                                 pd = null;
5480
5481                         LocalTemporary [] temps = null;
5482
5483                         if (dup_args)
5484                                 temps = new LocalTemporary [arguments.Count];
5485
5486                         //
5487                         // If we are calling a params method with no arguments, special case it
5488                         //
5489                         if (arguments == null){
5490                                 if (pd != null && pd.Count > 0 &&
5491                                     pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
5492                                         ILGenerator ig = ec.ig;
5493
5494                                         IntConstant.EmitInt (ig, 0);
5495                                         ig.Emit (OpCodes.Newarr, TypeManager.GetElementType (pd.ParameterType (0)));
5496                                 }
5497
5498                                 return;
5499                         }
5500
5501                         int top = arguments.Count;
5502
5503                         for (int i = 0; i < top; i++){
5504                                 Argument a = (Argument) arguments [i];
5505
5506                                 if (pd != null){
5507                                         if (pd.ParameterModifier (i) == Parameter.Modifier.PARAMS){
5508                                                 //
5509                                                 // Special case if we are passing the same data as the
5510                                                 // params argument, do not put it in an array.
5511                                                 //
5512                                                 if (pd.ParameterType (i) == a.Type)
5513                                                         a.Emit (ec);
5514                                                 else
5515                                                         EmitParams (ec, i, arguments);
5516                                                 return;
5517                                         }
5518                                 }
5519
5520                                 a.Emit (ec);
5521                                 if (dup_args) {
5522                                         ec.ig.Emit (OpCodes.Dup);
5523                                         (temps [i] = new LocalTemporary (ec, a.Type)).Store (ec);
5524                                 }
5525                         }
5526
5527                         if (dup_args) {
5528                                 if (this_arg != null)
5529                                         this_arg.Emit (ec);
5530
5531                                 for (int i = 0; i < top; i ++)
5532                                         temps [i].Emit (ec);
5533                         }
5534
5535                         if (pd != null && pd.Count > top &&
5536                             pd.ParameterModifier (top) == Parameter.Modifier.PARAMS){
5537                                 ILGenerator ig = ec.ig;
5538
5539                                 IntConstant.EmitInt (ig, 0);
5540                                 ig.Emit (OpCodes.Newarr, TypeManager.GetElementType (pd.ParameterType (top)));
5541                         }
5542                 }
5543
5544                 static Type[] GetVarargsTypes (EmitContext ec, MethodBase mb,
5545                                                ArrayList arguments)
5546                 {
5547                         ParameterData pd = TypeManager.GetParameterData (mb);
5548
5549                         if (arguments == null)
5550                                 return new Type [0];
5551
5552                         Argument a = (Argument) arguments [pd.Count - 1];
5553                         Arglist list = (Arglist) a.Expr;
5554
5555                         return list.ArgumentTypes;
5556                 }
5557
5558                 /// <summary>
5559                 /// This checks the ConditionalAttribute on the method
5560                 /// </summary>
5561                 static bool IsMethodExcluded (MethodBase method, EmitContext ec)
5562                 {
5563                         if (method.IsConstructor)
5564                                 return false;
5565
5566                         IMethodData md = TypeManager.GetMethod (method);
5567                         if (md != null)
5568                                 return md.IsExcluded (ec);
5569
5570                         // For some methods (generated by delegate class) GetMethod returns null
5571                         // because they are not included in builder_to_method table
5572                         if (method.DeclaringType is TypeBuilder)
5573                                 return false;
5574
5575                         return AttributeTester.IsConditionalMethodExcluded (method);
5576                 }
5577
5578                 /// <remarks>
5579                 ///   is_base tells whether we want to force the use of the `call'
5580                 ///   opcode instead of using callvirt.  Call is required to call
5581                 ///   a specific method, while callvirt will always use the most
5582                 ///   recent method in the vtable.
5583                 ///
5584                 ///   is_static tells whether this is an invocation on a static method
5585                 ///
5586                 ///   instance_expr is an expression that represents the instance
5587                 ///   it must be non-null if is_static is false.
5588                 ///
5589                 ///   method is the method to invoke.
5590                 ///
5591                 ///   Arguments is the list of arguments to pass to the method or constructor.
5592                 /// </remarks>
5593                 public static void EmitCall (EmitContext ec, bool is_base,
5594                                              bool is_static, Expression instance_expr,
5595                                              MethodBase method, ArrayList Arguments, Location loc)
5596                 {
5597                         EmitCall (ec, is_base, is_static, instance_expr, method, Arguments, loc, false, false);
5598                 }
5599
5600                 // `dup_args' leaves an extra copy of the arguments on the stack
5601                 // `omit_args' does not leave any arguments at all.
5602                 // So, basically, you could make one call with `dup_args' set to true,
5603                 // and then another with `omit_args' set to true, and the two calls
5604                 // would have the same set of arguments. However, each argument would
5605                 // only have been evaluated once.
5606                 public static void EmitCall (EmitContext ec, bool is_base,
5607                                              bool is_static, Expression instance_expr,
5608                                              MethodBase method, ArrayList Arguments, Location loc,
5609                                              bool dup_args, bool omit_args)
5610                 {
5611                         ILGenerator ig = ec.ig;
5612                         bool struct_call = false;
5613                         bool this_call = false;
5614                         LocalTemporary this_arg = null;
5615
5616                         Type decl_type = method.DeclaringType;
5617
5618                         if (!RootContext.StdLib) {
5619                                 // Replace any calls to the system's System.Array type with calls to
5620                                 // the newly created one.
5621                                 if (method == TypeManager.system_int_array_get_length)
5622                                         method = TypeManager.int_array_get_length;
5623                                 else if (method == TypeManager.system_int_array_get_rank)
5624                                         method = TypeManager.int_array_get_rank;
5625                                 else if (method == TypeManager.system_object_array_clone)
5626                                         method = TypeManager.object_array_clone;
5627                                 else if (method == TypeManager.system_int_array_get_length_int)
5628                                         method = TypeManager.int_array_get_length_int;
5629                                 else if (method == TypeManager.system_int_array_get_lower_bound_int)
5630                                         method = TypeManager.int_array_get_lower_bound_int;
5631                                 else if (method == TypeManager.system_int_array_get_upper_bound_int)
5632                                         method = TypeManager.int_array_get_upper_bound_int;
5633                                 else if (method == TypeManager.system_void_array_copyto_array_int)
5634                                         method = TypeManager.void_array_copyto_array_int;
5635                         }
5636
5637                         if (ec.TestObsoleteMethodUsage) {
5638                                 //
5639                                 // This checks ObsoleteAttribute on the method and on the declaring type
5640                                 //
5641                                 ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (method);
5642                                 if (oa != null)
5643                                         AttributeTester.Report_ObsoleteMessage (oa, TypeManager.CSharpSignature (method), loc);
5644
5645                                 oa = AttributeTester.GetObsoleteAttribute (method.DeclaringType);
5646                                 if (oa != null) {
5647                                         AttributeTester.Report_ObsoleteMessage (oa, method.DeclaringType.FullName, loc);
5648                                 }
5649                         }
5650
5651                         if (IsMethodExcluded (method, ec))
5652                                 return;
5653
5654                         if (!is_static){
5655                                 this_call = instance_expr == null;
5656                                 if (decl_type.IsValueType || (!this_call && instance_expr.Type.IsValueType))
5657                                         struct_call = true;
5658
5659                                 //
5660                                 // If this is ourselves, push "this"
5661                                 //
5662                                 if (!omit_args) {
5663                                         Type t = null;
5664                                         if (this_call) {
5665                                                 ig.Emit (OpCodes.Ldarg_0);
5666                                                 t = decl_type;
5667                                         } else {
5668                                                 Type iexpr_type = instance_expr.Type;
5669
5670                                                 //
5671                                                 // Push the instance expression
5672                                                 //
5673                                                 if (TypeManager.IsValueType (iexpr_type)) {
5674                                                         //
5675                                                         // Special case: calls to a function declared in a
5676                                                         // reference-type with a value-type argument need
5677                                                         // to have their value boxed.
5678                                                         if (decl_type.IsValueType ||
5679                                                             iexpr_type.IsGenericParameter) {
5680                                                                 //
5681                                                                 // If the expression implements IMemoryLocation, then
5682                                                                 // we can optimize and use AddressOf on the
5683                                                                 // return.
5684                                                                 //
5685                                                                 // If not we have to use some temporary storage for
5686                                                                 // it.
5687                                                                 if (instance_expr is IMemoryLocation) {
5688                                                                         ((IMemoryLocation)instance_expr).
5689                                                                                 AddressOf (ec, AddressOp.LoadStore);
5690                                                                 } else {
5691                                                                         LocalTemporary temp = new LocalTemporary (ec, iexpr_type);
5692                                                                         instance_expr.Emit (ec);
5693                                                                         temp.Store (ec);
5694                                                                         temp.AddressOf (ec, AddressOp.Load);
5695                                                                 }
5696
5697                                                                 // avoid the overhead of doing this all the time.
5698                                                                 if (dup_args)
5699                                                                         t = TypeManager.GetReferenceType (iexpr_type);
5700                                                         } else {
5701                                                                 instance_expr.Emit (ec);
5702                                                                 ig.Emit (OpCodes.Box, instance_expr.Type);
5703                                                                 t = TypeManager.object_type;
5704                                                         }
5705                                                 } else {
5706                                                         instance_expr.Emit (ec);
5707                                                         t = instance_expr.Type;
5708                                                 }
5709                                         }
5710
5711                                         if (dup_args) {
5712                                                 this_arg = new LocalTemporary (ec, t);
5713                                                 ig.Emit (OpCodes.Dup);
5714                                                 this_arg.Store (ec);
5715                                         }
5716                                 }
5717                         }
5718
5719                         if (!omit_args)
5720                                 EmitArguments (ec, method, Arguments, dup_args, this_arg);
5721
5722                         if ((instance_expr != null) && (instance_expr.Type.IsGenericParameter))
5723                                 ig.Emit (OpCodes.Constrained, instance_expr.Type);
5724
5725                         OpCode call_op;
5726                         if (is_static || struct_call || is_base || (this_call && !method.IsVirtual))
5727                                 call_op = OpCodes.Call;
5728                         else
5729                                 call_op = OpCodes.Callvirt;
5730
5731                         if ((method.CallingConvention & CallingConventions.VarArgs) != 0) {
5732                                 Type[] varargs_types = GetVarargsTypes (ec, method, Arguments);
5733                                 ig.EmitCall (call_op, (MethodInfo) method, varargs_types);
5734                                 return;
5735                         }
5736
5737                         //
5738                         // If you have:
5739                         // this.DoFoo ();
5740                         // and DoFoo is not virtual, you can omit the callvirt,
5741                         // because you don't need the null checking behavior.
5742                         //
5743                         if (method is MethodInfo)
5744                                 ig.Emit (call_op, (MethodInfo) method);
5745                         else
5746                                 ig.Emit (call_op, (ConstructorInfo) method);
5747                 }
5748
5749                 public override void Emit (EmitContext ec)
5750                 {
5751                         MethodGroupExpr mg = (MethodGroupExpr) this.expr;
5752
5753                         EmitCall (ec, mg.IsBase, method.IsStatic, mg.InstanceExpression, method, Arguments, loc);
5754                 }
5755
5756                 public override void EmitStatement (EmitContext ec)
5757                 {
5758                         Emit (ec);
5759
5760                         //
5761                         // Pop the return value if there is one
5762                         //
5763                         if (method is MethodInfo){
5764                                 Type ret = ((MethodInfo)method).ReturnType;
5765                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
5766                                         ec.ig.Emit (OpCodes.Pop);
5767                         }
5768                 }
5769         }
5770
5771         public class InvocationOrCast : ExpressionStatement
5772         {
5773                 Expression expr;
5774                 Expression argument;
5775
5776                 public InvocationOrCast (Expression expr, Expression argument, Location loc)
5777                 {
5778                         this.expr = expr;
5779                         this.argument = argument;
5780                         this.loc = loc;
5781                 }
5782
5783                 public override Expression DoResolve (EmitContext ec)
5784                 {
5785                         //
5786                         // First try to resolve it as a cast.
5787                         //
5788                         TypeExpr te = expr.ResolveAsTypeStep (ec) as TypeExpr;
5789                         if ((te != null) && (te.eclass == ExprClass.Type)) {
5790                                 Cast cast = new Cast (te, argument, loc);
5791                                 return cast.Resolve (ec);
5792                         }
5793
5794                         //
5795                         // This can either be a type or a delegate invocation.
5796                         // Let's just resolve it and see what we'll get.
5797                         //
5798                         expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
5799                         if (expr == null)
5800                                 return null;
5801
5802                         //
5803                         // Ok, so it's a Cast.
5804                         //
5805                         if (expr.eclass == ExprClass.Type) {
5806                                 Cast cast = new Cast (new TypeExpression (expr.Type, loc), argument, loc);
5807                                 return cast.Resolve (ec);
5808                         }
5809
5810                         //
5811                         // It's a delegate invocation.
5812                         //
5813                         if (!TypeManager.IsDelegateType (expr.Type)) {
5814                                 Error (149, "Method name expected");
5815                                 return null;
5816                         }
5817
5818                         ArrayList args = new ArrayList ();
5819                         args.Add (new Argument (argument, Argument.AType.Expression));
5820                         DelegateInvocation invocation = new DelegateInvocation (expr, args, loc);
5821                         return invocation.Resolve (ec);
5822                 }
5823
5824                 void error201 ()
5825                 {
5826                         Error (201, "Only assignment, call, increment, decrement and new object " +
5827                                "expressions can be used as a statement");
5828                 }
5829
5830                 public override ExpressionStatement ResolveStatement (EmitContext ec)
5831                 {
5832                         //
5833                         // First try to resolve it as a cast.
5834                         //
5835                         TypeExpr te = expr.ResolveAsTypeStep (ec) as TypeExpr;
5836                         if ((te != null) && (te.eclass == ExprClass.Type)) {
5837                                 error201 ();
5838                                 return null;
5839                         }
5840
5841                         //
5842                         // This can either be a type or a delegate invocation.
5843                         // Let's just resolve it and see what we'll get.
5844                         //
5845                         expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
5846                         if ((expr == null) || (expr.eclass == ExprClass.Type)) {
5847                                 error201 ();
5848                                 return null;
5849                         }
5850
5851                         //
5852                         // It's a delegate invocation.
5853                         //
5854                         if (!TypeManager.IsDelegateType (expr.Type)) {
5855                                 Error (149, "Method name expected");
5856                                 return null;
5857                         }
5858
5859                         ArrayList args = new ArrayList ();
5860                         args.Add (new Argument (argument, Argument.AType.Expression));
5861                         DelegateInvocation invocation = new DelegateInvocation (expr, args, loc);
5862                         return invocation.ResolveStatement (ec);
5863                 }
5864
5865                 public override void Emit (EmitContext ec)
5866                 {
5867                         throw new Exception ("Cannot happen");
5868                 }
5869
5870                 public override void EmitStatement (EmitContext ec)
5871                 {
5872                         throw new Exception ("Cannot happen");
5873                 }
5874         }
5875
5876         //
5877         // This class is used to "disable" the code generation for the
5878         // temporary variable when initializing value types.
5879         //
5880         class EmptyAddressOf : EmptyExpression, IMemoryLocation {
5881                 public void AddressOf (EmitContext ec, AddressOp Mode)
5882                 {
5883                         // nothing
5884                 }
5885         }
5886
5887         /// <summary>
5888         ///    Implements the new expression
5889         /// </summary>
5890         public class New : ExpressionStatement, IMemoryLocation {
5891                 public readonly ArrayList Arguments;
5892
5893                 //
5894                 // During bootstrap, it contains the RequestedType,
5895                 // but if `type' is not null, it *might* contain a NewDelegate
5896                 // (because of field multi-initialization)
5897                 //
5898                 public Expression RequestedType;
5899
5900                 MethodBase method = null;
5901
5902                 //
5903                 // If set, the new expression is for a value_target, and
5904                 // we will not leave anything on the stack.
5905                 //
5906                 Expression value_target;
5907                 bool value_target_set = false;
5908                 bool is_type_parameter = false;
5909
5910                 public New (Expression requested_type, ArrayList arguments, Location l)
5911                 {
5912                         RequestedType = requested_type;
5913                         Arguments = arguments;
5914                         loc = l;
5915                 }
5916
5917                 public bool SetValueTypeVariable (Expression value)
5918                 {
5919                         value_target = value;
5920                         value_target_set = true;
5921                         if (!(value_target is IMemoryLocation)){
5922                                 Error_UnexpectedKind ("variable", loc);
5923                                 return false;
5924                         }
5925                         return true;
5926                 }
5927
5928                 //
5929                 // This function is used to disable the following code sequence for
5930                 // value type initialization:
5931                 //
5932                 // AddressOf (temporary)
5933                 // Construct/Init
5934                 // LoadTemporary
5935                 //
5936                 // Instead the provide will have provided us with the address on the
5937                 // stack to store the results.
5938                 //
5939                 static Expression MyEmptyExpression;
5940
5941                 public void DisableTemporaryValueType ()
5942                 {
5943                         if (MyEmptyExpression == null)
5944                                 MyEmptyExpression = new EmptyAddressOf ();
5945
5946                         //
5947                         // To enable this, look into:
5948                         // test-34 and test-89 and self bootstrapping.
5949                         //
5950                         // For instance, we can avoid a copy by using `newobj'
5951                         // instead of Call + Push-temp on value types.
5952 //                      value_target = MyEmptyExpression;
5953                 }
5954
5955
5956                 /// <summary>
5957                 /// Converts complex core type syntax like 'new int ()' to simple constant
5958                 /// </summary>
5959                 Expression Constantify (Type t)
5960                 {
5961                         if (t == TypeManager.int32_type)
5962                                 return new IntConstant (0);
5963                         if (t == TypeManager.uint32_type)
5964                                 return new UIntConstant (0);
5965                         if (t == TypeManager.int64_type)
5966                                 return new LongConstant (0);
5967                         if (t == TypeManager.uint64_type)
5968                                 return new ULongConstant (0);
5969                         if (t == TypeManager.float_type)
5970                                 return new FloatConstant (0);
5971                         if (t == TypeManager.double_type)
5972                                 return new DoubleConstant (0);
5973                         if (t == TypeManager.short_type)
5974                                 return new ShortConstant (0);
5975                         if (t == TypeManager.ushort_type)
5976                                 return new UShortConstant (0);
5977                         if (t == TypeManager.sbyte_type)
5978                                 return new SByteConstant (0);
5979                         if (t == TypeManager.byte_type)
5980                                 return new ByteConstant (0);
5981                         if (t == TypeManager.char_type)
5982                                 return new CharConstant ('\0');
5983                         if (t == TypeManager.bool_type)
5984                                 return new BoolConstant (false);
5985                         if (t == TypeManager.decimal_type)
5986                                 return new DecimalConstant (0);
5987
5988                         return null;
5989                 }
5990
5991                 public override Expression DoResolve (EmitContext ec)
5992                 {
5993                         //
5994                         // The New DoResolve might be called twice when initializing field
5995                         // expressions (see EmitFieldInitializers, the call to
5996                         // GetInitializerExpression will perform a resolve on the expression,
5997                         // and later the assign will trigger another resolution
5998                         //
5999                         // This leads to bugs (#37014)
6000                         //
6001                         if (type != null){
6002                                 if (RequestedType is NewDelegate)
6003                                         return RequestedType;
6004                                 return this;
6005                         }
6006
6007                         TypeExpr texpr = RequestedType.ResolveAsTypeTerminal (ec);
6008                         if (texpr == null)
6009                                 return null;
6010
6011                         if (Arguments == null) {
6012                                 Expression c = Constantify (type);
6013                                 if (c != null)
6014                                         return c;
6015                         }
6016
6017                         type = texpr.Type;
6018                         if (type == null)
6019                                 return null;
6020
6021                         CheckObsoleteAttribute (type);
6022
6023                         bool IsDelegate = TypeManager.IsDelegateType (type);
6024
6025                         if (IsDelegate){
6026                                 RequestedType = (new NewDelegate (type, Arguments, loc)).Resolve (ec);
6027                                 if (RequestedType != null)
6028                                         if (!(RequestedType is DelegateCreation))
6029                                                 throw new Exception ("NewDelegate.Resolve returned a non NewDelegate: " + RequestedType.GetType ());
6030                                 return RequestedType;
6031                         }
6032
6033                         if (type.IsGenericParameter) {
6034                                 GenericConstraints gc = TypeManager.GetTypeParameterConstraints (type);
6035
6036                                 if ((gc == null) || (!gc.HasConstructorConstraint && !gc.IsValueType)) {
6037                                         Error (304, String.Format (
6038                                                        "Cannot create an instance of the " +
6039                                                        "variable type '{0}' because it " +
6040                                                        "doesn't have the new() constraint",
6041                                                        type));
6042                                         return null;
6043                                 }
6044
6045                                 if ((Arguments != null) && (Arguments.Count != 0)) {
6046                                         Error (417, String.Format (
6047                                                        "`{0}': cannot provide arguments " +
6048                                                        "when creating an instance of a " +
6049                                                        "variable type.", type));
6050                                         return null;
6051                                 }
6052
6053                                 is_type_parameter = true;
6054                                 eclass = ExprClass.Value;
6055                                 return this;
6056                         }
6057
6058                         if (type.IsAbstract && type.IsSealed) {
6059                                 Report.Error (712, loc, "Cannot create an instance of the static class '{0}'", TypeManager.CSharpName (type));
6060                                 return null;
6061                         }
6062
6063                         if (type.IsInterface || type.IsAbstract){
6064                                 Error (144, "It is not possible to create instances of interfaces or abstract classes");
6065                                 return null;
6066                         }
6067
6068                         bool is_struct = type.IsValueType;
6069                         eclass = ExprClass.Value;
6070
6071                         //
6072                         // SRE returns a match for .ctor () on structs (the object constructor),
6073                         // so we have to manually ignore it.
6074                         //
6075                         if (is_struct && Arguments == null)
6076                                 return this;
6077
6078                         Expression ml;
6079                         ml = MemberLookupFinal (ec, type, type, ".ctor",
6080                                                 // For member-lookup, treat 'new Foo (bar)' as call to 'foo.ctor (bar)', where 'foo' is of type 'Foo'.
6081                                                 MemberTypes.Constructor,
6082                                                 AllBindingFlags | BindingFlags.DeclaredOnly, loc);
6083
6084                         if (ml == null)
6085                                 return null;
6086
6087                         if (! (ml is MethodGroupExpr)){
6088                                 if (!is_struct){
6089                                         ml.Error_UnexpectedKind ("method group", loc);
6090                                         return null;
6091                                 }
6092                         }
6093
6094                         if (ml != null) {
6095                                 if (Arguments != null){
6096                                         foreach (Argument a in Arguments){
6097                                                 if (!a.Resolve (ec, loc))
6098                                                         return null;
6099                                         }
6100                                 }
6101
6102                                 method = Invocation.OverloadResolve (
6103                                         ec, (MethodGroupExpr) ml, Arguments, true, loc);
6104
6105                         }
6106
6107                         if (method == null) {
6108                                 if (almostMatchedMembers.Count != 0) {
6109                                         MemberLookupFailed (ec, type, type, ".ctor", null, true, loc);
6110                                         return null;
6111                                 }
6112
6113                                 if (!is_struct || Arguments.Count > 0) {
6114                                         Error (1501, String.Format (
6115                                             "New invocation: Can not find a constructor in `{0}' for this argument list",
6116                                             TypeManager.CSharpName (type)));
6117                                         return null;
6118                                 }
6119                         }
6120
6121                         return this;
6122                 }
6123
6124                 bool DoEmitTypeParameter (EmitContext ec)
6125                 {
6126                         ILGenerator ig = ec.ig;
6127
6128                         ig.Emit (OpCodes.Ldtoken, type);
6129                         ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
6130                         ig.Emit (OpCodes.Call, TypeManager.activator_create_instance);
6131                         ig.Emit (OpCodes.Unbox_Any, type);
6132
6133                         return true;
6134                 }
6135
6136                 //
6137                 // This DoEmit can be invoked in two contexts:
6138                 //    * As a mechanism that will leave a value on the stack (new object)
6139                 //    * As one that wont (init struct)
6140                 //
6141                 // You can control whether a value is required on the stack by passing
6142                 // need_value_on_stack.  The code *might* leave a value on the stack
6143                 // so it must be popped manually
6144                 //
6145                 // If we are dealing with a ValueType, we have a few
6146                 // situations to deal with:
6147                 //
6148                 //    * The target is a ValueType, and we have been provided
6149                 //      the instance (this is easy, we are being assigned).
6150                 //
6151                 //    * The target of New is being passed as an argument,
6152                 //      to a boxing operation or a function that takes a
6153                 //      ValueType.
6154                 //
6155                 //      In this case, we need to create a temporary variable
6156                 //      that is the argument of New.
6157                 //
6158                 // Returns whether a value is left on the stack
6159                 //
6160                 bool DoEmit (EmitContext ec, bool need_value_on_stack)
6161                 {
6162                         bool is_value_type = TypeManager.IsValueType (type);
6163                         ILGenerator ig = ec.ig;
6164
6165                         if (is_value_type){
6166                                 IMemoryLocation ml;
6167
6168                                 // Allow DoEmit() to be called multiple times.
6169                                 // We need to create a new LocalTemporary each time since
6170                                 // you can't share LocalBuilders among ILGeneators.
6171                                 if (!value_target_set)
6172                                         value_target = new LocalTemporary (ec, type);
6173
6174                                 ml = (IMemoryLocation) value_target;
6175                                 ml.AddressOf (ec, AddressOp.Store);
6176                         }
6177
6178                         if (method != null)
6179                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
6180
6181                         if (is_value_type){
6182                                 if (method == null)
6183                                         ig.Emit (OpCodes.Initobj, type);
6184                                 else
6185                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
6186                                 if (need_value_on_stack){
6187                                         value_target.Emit (ec);
6188                                         return true;
6189                                 }
6190                                 return false;
6191                         } else {
6192                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) method);
6193                                 return true;
6194                         }
6195                 }
6196
6197                 public override void Emit (EmitContext ec)
6198                 {
6199                         if (is_type_parameter)
6200                                 DoEmitTypeParameter (ec);
6201                         else
6202                                 DoEmit (ec, true);
6203                 }
6204
6205                 public override void EmitStatement (EmitContext ec)
6206                 {
6207                         if (is_type_parameter)
6208                                 throw new InvalidOperationException ();
6209
6210                         if (DoEmit (ec, false))
6211                                 ec.ig.Emit (OpCodes.Pop);
6212                 }
6213
6214                 public void AddressOf (EmitContext ec, AddressOp Mode)
6215                 {
6216                         if (is_type_parameter)
6217                                 throw new InvalidOperationException ();
6218
6219                         if (!type.IsValueType){
6220                                 //
6221                                 // We throw an exception.  So far, I believe we only need to support
6222                                 // value types:
6223                                 // foreach (int j in new StructType ())
6224                                 // see bug 42390
6225                                 //
6226                                 throw new Exception ("AddressOf should not be used for classes");
6227                         }
6228
6229                         if (!value_target_set)
6230                                 value_target = new LocalTemporary (ec, type);
6231
6232                         IMemoryLocation ml = (IMemoryLocation) value_target;
6233                         ml.AddressOf (ec, AddressOp.Store);
6234                         if (method != null)
6235                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
6236
6237                         if (method == null)
6238                                 ec.ig.Emit (OpCodes.Initobj, type);
6239                         else
6240                                 ec.ig.Emit (OpCodes.Call, (ConstructorInfo) method);
6241
6242                         ((IMemoryLocation) value_target).AddressOf (ec, Mode);
6243                 }
6244         }
6245
6246         /// <summary>
6247         ///   14.5.10.2: Represents an array creation expression.
6248         /// </summary>
6249         ///
6250         /// <remarks>
6251         ///   There are two possible scenarios here: one is an array creation
6252         ///   expression that specifies the dimensions and optionally the
6253         ///   initialization data and the other which does not need dimensions
6254         ///   specified but where initialization data is mandatory.
6255         /// </remarks>
6256         public class ArrayCreation : Expression {
6257                 Expression requested_base_type;
6258                 ArrayList initializers;
6259
6260                 //
6261                 // The list of Argument types.
6262                 // This is used to construct the `newarray' or constructor signature
6263                 //
6264                 ArrayList arguments;
6265
6266                 //
6267                 // Method used to create the array object.
6268                 //
6269                 MethodBase new_method = null;
6270
6271                 Type array_element_type;
6272                 Type underlying_type;
6273                 bool is_one_dimensional = false;
6274                 bool is_builtin_type = false;
6275                 bool expect_initializers = false;
6276                 int num_arguments = 0;
6277                 int dimensions = 0;
6278                 string rank;
6279
6280                 ArrayList array_data;
6281
6282                 Hashtable bounds;
6283
6284                 //
6285                 // The number of array initializers that we can handle
6286                 // via the InitializeArray method - through EmitStaticInitializers
6287                 //
6288                 int num_automatic_initializers;
6289
6290                 const int max_automatic_initializers = 6;
6291
6292                 public ArrayCreation (Expression requested_base_type, ArrayList exprs, string rank, ArrayList initializers, Location l)
6293                 {
6294                         this.requested_base_type = requested_base_type;
6295                         this.initializers = initializers;
6296                         this.rank = rank;
6297                         loc = l;
6298
6299                         arguments = new ArrayList ();
6300
6301                         foreach (Expression e in exprs) {
6302                                 arguments.Add (new Argument (e, Argument.AType.Expression));
6303                                 num_arguments++;
6304                         }
6305                 }
6306
6307                 public ArrayCreation (Expression requested_base_type, string rank, ArrayList initializers, Location l)
6308                 {
6309                         this.requested_base_type = requested_base_type;
6310                         this.initializers = initializers;
6311                         this.rank = rank;
6312                         loc = l;
6313
6314                         //this.rank = rank.Substring (0, rank.LastIndexOf ('['));
6315                         //
6316                         //string tmp = rank.Substring (rank.LastIndexOf ('['));
6317                         //
6318                         //dimensions = tmp.Length - 1;
6319                         expect_initializers = true;
6320                 }
6321
6322                 public Expression FormArrayType (Expression base_type, int idx_count, string rank)
6323                 {
6324                         StringBuilder sb = new StringBuilder (rank);
6325
6326                         sb.Append ("[");
6327                         for (int i = 1; i < idx_count; i++)
6328                                 sb.Append (",");
6329
6330                         sb.Append ("]");
6331
6332                         return new ComposedCast (base_type, sb.ToString (), loc);
6333                 }
6334
6335                 void Error_IncorrectArrayInitializer ()
6336                 {
6337                         Error (178, "Incorrectly structured array initializer");
6338                 }
6339
6340                 public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
6341                 {
6342                         if (specified_dims) {
6343                                 Argument a = (Argument) arguments [idx];
6344
6345                                 if (!a.Resolve (ec, loc))
6346                                         return false;
6347
6348                                 if (!(a.Expr is Constant)) {
6349                                         Error (150, "A constant value is expected");
6350                                         return false;
6351                                 }
6352
6353                                 int value = (int) ((Constant) a.Expr).GetValue ();
6354
6355                                 if (value != probe.Count) {
6356                                         Error_IncorrectArrayInitializer ();
6357                                         return false;
6358                                 }
6359
6360                                 bounds [idx] = value;
6361                         }
6362
6363                         int child_bounds = -1;
6364                         for (int i = 0; i < probe.Count; ++i) {
6365                                 object o = probe [i];
6366                                 if (o is ArrayList) {
6367                                         ArrayList sub_probe = o as ArrayList;
6368                                         int current_bounds = sub_probe.Count;
6369
6370                                         if (child_bounds == -1)
6371                                                 child_bounds = current_bounds;
6372
6373                                         else if (child_bounds != current_bounds){
6374                                                 Error_IncorrectArrayInitializer ();
6375                                                 return false;
6376                                         }
6377                                         if (specified_dims && (idx + 1 >= arguments.Count)){
6378                                                 Error (623, "Array initializers can only be used in a variable or field initializer, try using the new expression");
6379                                                 return false;
6380                                         }
6381
6382                                         bool ret = CheckIndices (ec, sub_probe, idx + 1, specified_dims);
6383                                         if (!ret)
6384                                                 return false;
6385                                 } else {
6386                                         if (child_bounds != -1){
6387                                                 Error_IncorrectArrayInitializer ();
6388                                                 return false;
6389                                         }
6390
6391                                         Expression tmp = (Expression) o;
6392                                         tmp = tmp.Resolve (ec);
6393                                         probe [i] = tmp;
6394                                         if (tmp == null)
6395                                                 return false;
6396
6397                                         // Console.WriteLine ("I got: " + tmp);
6398                                         // Handle initialization from vars, fields etc.
6399
6400                                         Expression conv = Convert.ImplicitConversionRequired (
6401                                                 ec, tmp, underlying_type, loc);
6402
6403                                         if (conv == null)
6404                                                 return false;
6405
6406                                         if (conv is StringConstant || conv is DecimalConstant || conv is NullCast) {
6407                                                 // These are subclasses of Constant that can appear as elements of an
6408                                                 // array that cannot be statically initialized (with num_automatic_initializers
6409                                                 // > max_automatic_initializers), so num_automatic_initializers should be left as zero.
6410                                                 array_data.Add (conv);
6411                                         } else if (conv is Constant) {
6412                                                 // These are the types of Constant that can appear in arrays that can be
6413                                                 // statically allocated.
6414                                                 array_data.Add (conv);
6415                                                 num_automatic_initializers++;
6416                                         } else
6417                                                 array_data.Add (conv);
6418                                 }
6419                         }
6420
6421                         return true;
6422                 }
6423
6424                 public void UpdateIndices (EmitContext ec)
6425                 {
6426                         int i = 0;
6427                         for (ArrayList probe = initializers; probe != null;) {
6428                                 if (probe.Count > 0 && probe [0] is ArrayList) {
6429                                         Expression e = new IntConstant (probe.Count);
6430                                         arguments.Add (new Argument (e, Argument.AType.Expression));
6431
6432                                         bounds [i++] =  probe.Count;
6433
6434                                         probe = (ArrayList) probe [0];
6435
6436                                 } else {
6437                                         Expression e = new IntConstant (probe.Count);
6438                                         arguments.Add (new Argument (e, Argument.AType.Expression));
6439
6440                                         bounds [i++] = probe.Count;
6441                                         probe = null;
6442                                 }
6443                         }
6444
6445                 }
6446
6447                 public bool ValidateInitializers (EmitContext ec, Type array_type)
6448                 {
6449                         if (initializers == null) {
6450                                 if (expect_initializers)
6451                                         return false;
6452                                 else
6453                                         return true;
6454                         }
6455
6456                         if (underlying_type == null)
6457                                 return false;
6458
6459                         //
6460                         // We use this to store all the date values in the order in which we
6461                         // will need to store them in the byte blob later
6462                         //
6463                         array_data = new ArrayList ();
6464                         bounds = new Hashtable ();
6465
6466                         bool ret;
6467
6468                         if (arguments != null) {
6469                                 ret = CheckIndices (ec, initializers, 0, true);
6470                                 return ret;
6471                         } else {
6472                                 arguments = new ArrayList ();
6473
6474                                 ret = CheckIndices (ec, initializers, 0, false);
6475
6476                                 if (!ret)
6477                                         return false;
6478
6479                                 UpdateIndices (ec);
6480
6481                                 if (arguments.Count != dimensions) {
6482                                         Error_IncorrectArrayInitializer ();
6483                                         return false;
6484                                 }
6485
6486                                 return ret;
6487                         }
6488                 }
6489
6490                 //
6491                 // Creates the type of the array
6492                 //
6493                 bool LookupType (EmitContext ec)
6494                 {
6495                         StringBuilder array_qualifier = new StringBuilder (rank);
6496
6497                         //
6498                         // `In the first form allocates an array instace of the type that results
6499                         // from deleting each of the individual expression from the expression list'
6500                         //
6501                         if (num_arguments > 0) {
6502                                 array_qualifier.Append ("[");
6503                                 for (int i = num_arguments-1; i > 0; i--)
6504                                         array_qualifier.Append (",");
6505                                 array_qualifier.Append ("]");
6506                         }
6507
6508                         //
6509                         // Lookup the type
6510                         //
6511                         TypeExpr array_type_expr;
6512                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
6513                         array_type_expr = array_type_expr.ResolveAsTypeTerminal (ec);
6514                         if (array_type_expr == null)
6515                                 return false;
6516
6517                         type = array_type_expr.Type;
6518
6519                         if (!type.IsArray) {
6520                                 Error (622, "Can only use array initializer expressions to assign to array types. Try using a new expression instead.");
6521                                 return false;
6522                         }
6523                         underlying_type = TypeManager.GetElementType (type);
6524                         dimensions = type.GetArrayRank ();
6525
6526                         return true;
6527                 }
6528
6529                 public override Expression DoResolve (EmitContext ec)
6530                 {
6531                         int arg_count;
6532
6533                         if (!LookupType (ec))
6534                                 return null;
6535
6536                         //
6537                         // First step is to validate the initializers and fill
6538                         // in any missing bits
6539                         //
6540                         if (!ValidateInitializers (ec, type))
6541                                 return null;
6542
6543                         if (arguments == null)
6544                                 arg_count = 0;
6545                         else {
6546                                 arg_count = arguments.Count;
6547                                 foreach (Argument a in arguments){
6548                                         if (!a.Resolve (ec, loc))
6549                                                 return null;
6550
6551                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
6552                                         if (real_arg == null)
6553                                                 return null;
6554
6555                                         a.Expr = real_arg;
6556                                 }
6557                         }
6558
6559                         array_element_type = TypeManager.GetElementType (type);
6560
6561                         if (array_element_type.IsAbstract && array_element_type.IsSealed) {
6562                                 Report.Error (719, loc, "'{0}': array elements cannot be of static type", TypeManager.CSharpName (array_element_type));
6563                                 return null;
6564                         }
6565
6566                         if (arg_count == 1) {
6567                                 is_one_dimensional = true;
6568                                 eclass = ExprClass.Value;
6569                                 return this;
6570                         }
6571
6572                         is_builtin_type = TypeManager.IsBuiltinType (type);
6573
6574                         if (is_builtin_type) {
6575                                 Expression ml;
6576
6577                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
6578                                                    AllBindingFlags, loc);
6579
6580                                 if (!(ml is MethodGroupExpr)) {
6581                                         ml.Error_UnexpectedKind ("method group", loc);
6582                                         return null;
6583                                 }
6584
6585                                 if (ml == null) {
6586                                         Error (-6, "New invocation: Can not find a constructor for " +
6587                                                       "this argument list");
6588                                         return null;
6589                                 }
6590
6591                                 new_method = Invocation.OverloadResolve (
6592                                         ec, (MethodGroupExpr) ml, arguments, false, loc);
6593
6594                                 if (new_method == null) {
6595                                         Error (-6, "New invocation: Can not find a constructor for " +
6596                                                       "this argument list");
6597                                         return null;
6598                                 }
6599
6600                                 eclass = ExprClass.Value;
6601                                 return this;
6602                         } else {
6603                                 ModuleBuilder mb = CodeGen.Module.Builder;
6604                                 ArrayList args = new ArrayList ();
6605
6606                                 if (arguments != null) {
6607                                         for (int i = 0; i < arg_count; i++)
6608                                                 args.Add (TypeManager.int32_type);
6609                                 }
6610
6611                                 Type [] arg_types = null;
6612
6613                                 if (args.Count > 0)
6614                                         arg_types = new Type [args.Count];
6615
6616                                 args.CopyTo (arg_types, 0);
6617
6618                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
6619                                                             arg_types);
6620
6621                                 if (new_method == null) {
6622                                         Error (-6, "New invocation: Can not find a constructor for " +
6623                                                       "this argument list");
6624                                         return null;
6625                                 }
6626
6627                                 eclass = ExprClass.Value;
6628                                 return this;
6629                         }
6630                 }
6631
6632                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
6633                 {
6634                         int factor;
6635                         byte [] data;
6636                         byte [] element;
6637                         int count = array_data.Count;
6638
6639                         if (underlying_type.IsEnum)
6640                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
6641
6642                         factor = GetTypeSize (underlying_type);
6643                         if (factor == 0)
6644                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
6645
6646                         data = new byte [(count * factor + 4) & ~3];
6647                         int idx = 0;
6648
6649                         for (int i = 0; i < count; ++i) {
6650                                 object v = array_data [i];
6651
6652                                 if (v is EnumConstant)
6653                                         v = ((EnumConstant) v).Child;
6654
6655                                 if (v is Constant && !(v is StringConstant))
6656                                         v = ((Constant) v).GetValue ();
6657                                 else {
6658                                         idx += factor;
6659                                         continue;
6660                                 }
6661
6662                                 if (underlying_type == TypeManager.int64_type){
6663                                         if (!(v is Expression)){
6664                                                 long val = (long) v;
6665
6666                                                 for (int j = 0; j < factor; ++j) {
6667                                                         data [idx + j] = (byte) (val & 0xFF);
6668                                                         val = (val >> 8);
6669                                                 }
6670                                         }
6671                                 } else if (underlying_type == TypeManager.uint64_type){
6672                                         if (!(v is Expression)){
6673                                                 ulong val = (ulong) v;
6674
6675                                                 for (int j = 0; j < factor; ++j) {
6676                                                         data [idx + j] = (byte) (val & 0xFF);
6677                                                         val = (val >> 8);
6678                                                 }
6679                                         }
6680                                 } else if (underlying_type == TypeManager.float_type) {
6681                                         if (!(v is Expression)){
6682                                                 element = BitConverter.GetBytes ((float) v);
6683
6684                                                 for (int j = 0; j < factor; ++j)
6685                                                         data [idx + j] = element [j];
6686                                         }
6687                                 } else if (underlying_type == TypeManager.double_type) {
6688                                         if (!(v is Expression)){
6689                                                 element = BitConverter.GetBytes ((double) v);
6690
6691                                                 for (int j = 0; j < factor; ++j)
6692                                                         data [idx + j] = element [j];
6693                                         }
6694                                 } else if (underlying_type == TypeManager.char_type){
6695                                         if (!(v is Expression)){
6696                                                 int val = (int) ((char) v);
6697
6698                                                 data [idx] = (byte) (val & 0xff);
6699                                                 data [idx+1] = (byte) (val >> 8);
6700                                         }
6701                                 } else if (underlying_type == TypeManager.short_type){
6702                                         if (!(v is Expression)){
6703                                                 int val = (int) ((short) v);
6704
6705                                                 data [idx] = (byte) (val & 0xff);
6706                                                 data [idx+1] = (byte) (val >> 8);
6707                                         }
6708                                 } else if (underlying_type == TypeManager.ushort_type){
6709                                         if (!(v is Expression)){
6710                                                 int val = (int) ((ushort) v);
6711
6712                                                 data [idx] = (byte) (val & 0xff);
6713                                                 data [idx+1] = (byte) (val >> 8);
6714                                         }
6715                                 } else if (underlying_type == TypeManager.int32_type) {
6716                                         if (!(v is Expression)){
6717                                                 int val = (int) v;
6718
6719                                                 data [idx]   = (byte) (val & 0xff);
6720                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6721                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6722                                                 data [idx+3] = (byte) (val >> 24);
6723                                         }
6724                                 } else if (underlying_type == TypeManager.uint32_type) {
6725                                         if (!(v is Expression)){
6726                                                 uint val = (uint) v;
6727
6728                                                 data [idx]   = (byte) (val & 0xff);
6729                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6730                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6731                                                 data [idx+3] = (byte) (val >> 24);
6732                                         }
6733                                 } else if (underlying_type == TypeManager.sbyte_type) {
6734                                         if (!(v is Expression)){
6735                                                 sbyte val = (sbyte) v;
6736                                                 data [idx] = (byte) val;
6737                                         }
6738                                 } else if (underlying_type == TypeManager.byte_type) {
6739                                         if (!(v is Expression)){
6740                                                 byte val = (byte) v;
6741                                                 data [idx] = (byte) val;
6742                                         }
6743                                 } else if (underlying_type == TypeManager.bool_type) {
6744                                         if (!(v is Expression)){
6745                                                 bool val = (bool) v;
6746                                                 data [idx] = (byte) (val ? 1 : 0);
6747                                         }
6748                                 } else if (underlying_type == TypeManager.decimal_type){
6749                                         if (!(v is Expression)){
6750                                                 int [] bits = Decimal.GetBits ((decimal) v);
6751                                                 int p = idx;
6752
6753                                                 // FIXME: For some reason, this doesn't work on the MS runtime.
6754                                                 int [] nbits = new int [4];
6755                                                 nbits [0] = bits [3];
6756                                                 nbits [1] = bits [2];
6757                                                 nbits [2] = bits [0];
6758                                                 nbits [3] = bits [1];
6759
6760                                                 for (int j = 0; j < 4; j++){
6761                                                         data [p++] = (byte) (nbits [j] & 0xff);
6762                                                         data [p++] = (byte) ((nbits [j] >> 8) & 0xff);
6763                                                         data [p++] = (byte) ((nbits [j] >> 16) & 0xff);
6764                                                         data [p++] = (byte) (nbits [j] >> 24);
6765                                                 }
6766                                         }
6767                                 } else
6768                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
6769
6770                                 idx += factor;
6771                         }
6772
6773                         return data;
6774                 }
6775
6776                 //
6777                 // Emits the initializers for the array
6778                 //
6779                 void EmitStaticInitializers (EmitContext ec)
6780                 {
6781                         //
6782                         // First, the static data
6783                         //
6784                         FieldBuilder fb;
6785                         ILGenerator ig = ec.ig;
6786
6787                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
6788
6789                         fb = RootContext.MakeStaticData (data);
6790
6791                         ig.Emit (OpCodes.Dup);
6792                         ig.Emit (OpCodes.Ldtoken, fb);
6793                         ig.Emit (OpCodes.Call,
6794                                  TypeManager.void_initializearray_array_fieldhandle);
6795                 }
6796
6797                 //
6798                 // Emits pieces of the array that can not be computed at compile
6799                 // time (variables and string locations).
6800                 //
6801                 // This always expect the top value on the stack to be the array
6802                 //
6803                 void EmitDynamicInitializers (EmitContext ec)
6804                 {
6805                         ILGenerator ig = ec.ig;
6806                         int dims = bounds.Count;
6807                         int [] current_pos = new int [dims];
6808                         int top = array_data.Count;
6809
6810                         MethodInfo set = null;
6811
6812                         if (dims != 1){
6813                                 Type [] args;
6814                                 ModuleBuilder mb = null;
6815                                 mb = CodeGen.Module.Builder;
6816                                 args = new Type [dims + 1];
6817
6818                                 int j;
6819                                 for (j = 0; j < dims; j++)
6820                                         args [j] = TypeManager.int32_type;
6821
6822                                 args [j] = array_element_type;
6823
6824                                 set = mb.GetArrayMethod (
6825                                         type, "Set",
6826                                         CallingConventions.HasThis | CallingConventions.Standard,
6827                                         TypeManager.void_type, args);
6828                         }
6829
6830                         for (int i = 0; i < top; i++){
6831
6832                                 Expression e = null;
6833
6834                                 if (array_data [i] is Expression)
6835                                         e = (Expression) array_data [i];
6836
6837                                 if (e != null) {
6838                                         //
6839                                         // Basically we do this for string literals and
6840                                         // other non-literal expressions
6841                                         //
6842                                         if (e is EnumConstant){
6843                                                 e = ((EnumConstant) e).Child;
6844                                         }
6845
6846                                         if (e is StringConstant || e is DecimalConstant || !(e is Constant) ||
6847                                             num_automatic_initializers <= max_automatic_initializers) {
6848                                                 Type etype = e.Type;
6849
6850                                                 ig.Emit (OpCodes.Dup);
6851
6852                                                 for (int idx = 0; idx < dims; idx++)
6853                                                         IntConstant.EmitInt (ig, current_pos [idx]);
6854
6855                                                 //
6856                                                 // If we are dealing with a struct, get the
6857                                                 // address of it, so we can store it.
6858                                                 //
6859                                                 if ((dims == 1) && etype.IsValueType &&
6860                                                     (!TypeManager.IsBuiltinOrEnum (etype) ||
6861                                                      etype == TypeManager.decimal_type)) {
6862                                                         if (e is New){
6863                                                                 New n = (New) e;
6864
6865                                                                 //
6866                                                                 // Let new know that we are providing
6867                                                                 // the address where to store the results
6868                                                                 //
6869                                                                 n.DisableTemporaryValueType ();
6870                                                         }
6871
6872                                                         ig.Emit (OpCodes.Ldelema, etype);
6873                                                 }
6874
6875                                                 e.Emit (ec);
6876
6877                                                 if (dims == 1) {
6878                                                         bool is_stobj, has_type_arg;
6879                                                         OpCode op = ArrayAccess.GetStoreOpcode (
6880                                                                 etype, out is_stobj,
6881                                                                 out has_type_arg);
6882                                                         if (is_stobj)
6883                                                                 ig.Emit (OpCodes.Stobj, etype);
6884                                                         else if (has_type_arg)
6885                                                                 ig.Emit (op, etype);
6886                                                         else
6887                                                                 ig.Emit (op);
6888                                                 } else
6889                                                         ig.Emit (OpCodes.Call, set);
6890                                         }
6891                                 }
6892
6893                                 //
6894                                 // Advance counter
6895                                 //
6896                                 for (int j = dims - 1; j >= 0; j--){
6897                                         current_pos [j]++;
6898                                         if (current_pos [j] < (int) bounds [j])
6899                                                 break;
6900                                         current_pos [j] = 0;
6901                                 }
6902                         }
6903                 }
6904
6905                 void EmitArrayArguments (EmitContext ec)
6906                 {
6907                         ILGenerator ig = ec.ig;
6908
6909                         foreach (Argument a in arguments) {
6910                                 Type atype = a.Type;
6911                                 a.Emit (ec);
6912
6913                                 if (atype == TypeManager.uint64_type)
6914                                         ig.Emit (OpCodes.Conv_Ovf_U4);
6915                                 else if (atype == TypeManager.int64_type)
6916                                         ig.Emit (OpCodes.Conv_Ovf_I4);
6917                         }
6918                 }
6919
6920                 public override void Emit (EmitContext ec)
6921                 {
6922                         ILGenerator ig = ec.ig;
6923
6924                         EmitArrayArguments (ec);
6925                         if (is_one_dimensional)
6926                                 ig.Emit (OpCodes.Newarr, array_element_type);
6927                         else {
6928                                 if (is_builtin_type)
6929                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
6930                                 else
6931                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
6932                         }
6933
6934                         if (initializers != null){
6935                                 //
6936                                 // FIXME: Set this variable correctly.
6937                                 //
6938                                 bool dynamic_initializers = true;
6939
6940                                 // This will never be true for array types that cannot be statically
6941                                 // initialized. num_automatic_initializers will always be zero.  See
6942                                 // CheckIndices.
6943                                         if (num_automatic_initializers > max_automatic_initializers)
6944                                                 EmitStaticInitializers (ec);
6945
6946                                 if (dynamic_initializers)
6947                                         EmitDynamicInitializers (ec);
6948                         }
6949                 }
6950
6951                 public object EncodeAsAttribute ()
6952                 {
6953                         if (!is_one_dimensional){
6954                                 Report.Error (-211, Location, "attribute can not encode multi-dimensional arrays");
6955                                 return null;
6956                         }
6957
6958                         if (array_data == null){
6959                                 Report.Error (-212, Location, "array should be initialized when passing it to an attribute");
6960                                 return null;
6961                         }
6962
6963                         object [] ret = new object [array_data.Count];
6964                         int i = 0;
6965                         foreach (Expression e in array_data){
6966                                 object v;
6967
6968                                 if (e is NullLiteral)
6969                                         v = null;
6970                                 else {
6971                                         if (!Attribute.GetAttributeArgumentExpression (e, Location, array_element_type, out v))
6972                                                 return null;
6973                                 }
6974                                 ret [i++] = v;
6975                         }
6976                         return ret;
6977                 }
6978         }
6979
6980         /// <summary>
6981         ///   Represents the `this' construct
6982         /// </summary>
6983         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
6984
6985                 Block block;
6986                 VariableInfo variable_info;
6987
6988                 public This (Block block, Location loc)
6989                 {
6990                         this.loc = loc;
6991                         this.block = block;
6992                 }
6993
6994                 public This (Location loc)
6995                 {
6996                         this.loc = loc;
6997                 }
6998
6999                 public VariableInfo VariableInfo {
7000                         get { return variable_info; }
7001                 }
7002
7003                 public bool VerifyFixed (bool is_expression)
7004                 {
7005                         if ((variable_info == null) || (variable_info.LocalInfo == null))
7006                                 return false;
7007                         else
7008                                 return variable_info.LocalInfo.IsFixed;
7009                 }
7010
7011                 public bool ResolveBase (EmitContext ec)
7012                 {
7013                         eclass = ExprClass.Variable;
7014
7015                         if (ec.TypeContainer.CurrentType != null)
7016                                 type = ec.TypeContainer.CurrentType;
7017                         else
7018                                 type = ec.ContainerType;
7019
7020                         if (ec.IsStatic) {
7021                                 Error (26, "Keyword this not valid in static code");
7022                                 return false;
7023                         }
7024
7025                         if ((block != null) && (block.ThisVariable != null))
7026                                 variable_info = block.ThisVariable.VariableInfo;
7027
7028                         if (ec.CurrentAnonymousMethod != null)
7029                                 ec.CaptureThis ();
7030
7031                         return true;
7032                 }
7033
7034                 public override Expression DoResolve (EmitContext ec)
7035                 {
7036                         if (!ResolveBase (ec))
7037                                 return null;
7038
7039                         if ((variable_info != null) && !variable_info.IsAssigned (ec)) {
7040                                 Error (188, "The this object cannot be used before all " +
7041                                        "of its fields are assigned to");
7042                                 variable_info.SetAssigned (ec);
7043                                 return this;
7044                         }
7045
7046                         if (ec.IsFieldInitializer) {
7047                                 Error (27, "Keyword `this' can't be used outside a constructor, " +
7048                                        "a method or a property.");
7049                                 return null;
7050                         }
7051
7052                         return this;
7053                 }
7054
7055                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
7056                 {
7057                         if (!ResolveBase (ec))
7058                                 return null;
7059
7060                         if (variable_info != null)
7061                                 variable_info.SetAssigned (ec);
7062
7063                         if (ec.TypeContainer is Class){
7064                                 Error (1604, "Cannot assign to 'this' because it is read-only");
7065                                 return null;
7066                         }
7067
7068                         return this;
7069                 }
7070
7071                 public void Emit (EmitContext ec, bool leave_copy)
7072                 {
7073                         Emit (ec);
7074                         if (leave_copy)
7075                                 ec.ig.Emit (OpCodes.Dup);
7076                 }
7077
7078                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
7079                 {
7080                         ILGenerator ig = ec.ig;
7081
7082                         if (ec.TypeContainer is Struct){
7083                                 ec.EmitThis ();
7084                                 source.Emit (ec);
7085                                 if (leave_copy)
7086                                         ec.ig.Emit (OpCodes.Dup);
7087                                 ig.Emit (OpCodes.Stobj, type);
7088                         } else {
7089                                 throw new Exception ("how did you get here");
7090                         }
7091                 }
7092
7093                 public override void Emit (EmitContext ec)
7094                 {
7095                         ILGenerator ig = ec.ig;
7096
7097                         ec.EmitThis ();
7098                         if (ec.TypeContainer is Struct)
7099                                 ig.Emit (OpCodes.Ldobj, type);
7100                 }
7101
7102                 public override int GetHashCode()
7103                 {
7104                         return block.GetHashCode ();
7105                 }
7106
7107                 public override bool Equals (object obj)
7108                 {
7109                         This t = obj as This;
7110                         if (t == null)
7111                                 return false;
7112
7113                         return block == t.block;
7114                 }
7115
7116                 public void AddressOf (EmitContext ec, AddressOp mode)
7117                 {
7118                         ec.EmitThis ();
7119
7120                         // FIMXE
7121                         // FIGURE OUT WHY LDARG_S does not work
7122                         //
7123                         // consider: struct X { int val; int P { set { val = value; }}}
7124                         //
7125                         // Yes, this looks very bad. Look at `NOTAS' for
7126                         // an explanation.
7127                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
7128                 }
7129         }
7130
7131         /// <summary>
7132         ///   Represents the `__arglist' construct
7133         /// </summary>
7134         public class ArglistAccess : Expression
7135         {
7136                 public ArglistAccess (Location loc)
7137                 {
7138                         this.loc = loc;
7139                 }
7140
7141                 public bool ResolveBase (EmitContext ec)
7142                 {
7143                         eclass = ExprClass.Variable;
7144                         type = TypeManager.runtime_argument_handle_type;
7145                         return true;
7146                 }
7147
7148                 public override Expression DoResolve (EmitContext ec)
7149                 {
7150                         if (!ResolveBase (ec))
7151                                 return null;
7152
7153                         if (ec.IsFieldInitializer || !ec.CurrentBlock.HasVarargs) {
7154                                 Error (190, "The __arglist construct is valid only within " +
7155                                        "a variable argument method.");
7156                                 return null;
7157                         }
7158
7159                         return this;
7160                 }
7161
7162                 public override void Emit (EmitContext ec)
7163                 {
7164                         ec.ig.Emit (OpCodes.Arglist);
7165                 }
7166         }
7167
7168         /// <summary>
7169         ///   Represents the `__arglist (....)' construct
7170         /// </summary>
7171         public class Arglist : Expression
7172         {
7173                 public readonly Argument[] Arguments;
7174
7175                 public Arglist (Argument[] args, Location l)
7176                 {
7177                         Arguments = args;
7178                         loc = l;
7179                 }
7180
7181                 public Type[] ArgumentTypes {
7182                         get {
7183                                 Type[] retval = new Type [Arguments.Length];
7184                                 for (int i = 0; i < Arguments.Length; i++)
7185                                         retval [i] = Arguments [i].Type;
7186                                 return retval;
7187                         }
7188                 }
7189
7190                 public override Expression DoResolve (EmitContext ec)
7191                 {
7192                         eclass = ExprClass.Variable;
7193                         type = TypeManager.runtime_argument_handle_type;
7194
7195                         foreach (Argument arg in Arguments) {
7196                                 if (!arg.Resolve (ec, loc))
7197                                         return null;
7198                         }
7199
7200                         return this;
7201                 }
7202
7203                 public override void Emit (EmitContext ec)
7204                 {
7205                         foreach (Argument arg in Arguments)
7206                                 arg.Emit (ec);
7207                 }
7208         }
7209
7210         //
7211         // This produces the value that renders an instance, used by the iterators code
7212         //
7213         public class ProxyInstance : Expression, IMemoryLocation  {
7214                 public override Expression DoResolve (EmitContext ec)
7215                 {
7216                         eclass = ExprClass.Variable;
7217                         type = ec.ContainerType;
7218                         return this;
7219                 }
7220
7221                 public override void Emit (EmitContext ec)
7222                 {
7223                         ec.ig.Emit (OpCodes.Ldarg_0);
7224
7225                 }
7226
7227                 public void AddressOf (EmitContext ec, AddressOp mode)
7228                 {
7229                         ec.ig.Emit (OpCodes.Ldarg_0);
7230                 }
7231         }
7232
7233         /// <summary>
7234         ///   Implements the typeof operator
7235         /// </summary>
7236         public class TypeOf : Expression {
7237                 public Expression QueriedType;
7238                 protected Type typearg;
7239
7240                 public TypeOf (Expression queried_type, Location l)
7241                 {
7242                         QueriedType = queried_type;
7243                         loc = l;
7244                 }
7245
7246                 public override Expression DoResolve (EmitContext ec)
7247                 {
7248                         TypeExpr texpr = QueriedType.ResolveAsTypeTerminal (ec);
7249                         if (texpr == null)
7250                                 return null;
7251
7252                         typearg = texpr.Type;
7253
7254                         if (typearg == TypeManager.void_type) {
7255                                 Error (673, "System.Void cannot be used from C# - " +
7256                                        "use typeof (void) to get the void type object");
7257                                 return null;
7258                         }
7259
7260                         if (typearg.IsPointer && !ec.InUnsafe){
7261                                 UnsafeError (loc);
7262                                 return null;
7263                         }
7264                         CheckObsoleteAttribute (typearg);
7265
7266                         type = TypeManager.type_type;
7267                         eclass = ExprClass.Type;
7268                         return this;
7269                 }
7270
7271                 public override void Emit (EmitContext ec)
7272                 {
7273                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
7274                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
7275                 }
7276
7277                 public Type TypeArg {
7278                         get { return typearg; }
7279                 }
7280         }
7281
7282         /// <summary>
7283         ///   Implements the `typeof (void)' operator
7284         /// </summary>
7285         public class TypeOfVoid : TypeOf {
7286                 public TypeOfVoid (Location l) : base (null, l)
7287                 {
7288                         loc = l;
7289                 }
7290
7291                 public override Expression DoResolve (EmitContext ec)
7292                 {
7293                         type = TypeManager.type_type;
7294                         typearg = TypeManager.void_type;
7295                         eclass = ExprClass.Type;
7296                         return this;
7297                 }
7298         }
7299
7300         /// <summary>
7301         ///   Implements the sizeof expression
7302         /// </summary>
7303         public class SizeOf : Expression {
7304                 public Expression QueriedType;
7305                 Type type_queried;
7306
7307                 public SizeOf (Expression queried_type, Location l)
7308                 {
7309                         this.QueriedType = queried_type;
7310                         loc = l;
7311                 }
7312
7313                 public override Expression DoResolve (EmitContext ec)
7314                 {
7315                         TypeExpr texpr = QueriedType.ResolveAsTypeTerminal (ec);
7316                         if (texpr == null)
7317                                 return null;
7318
7319                         if (texpr is TypeParameterExpr){
7320                                 ((TypeParameterExpr)texpr).Error_CannotUseAsUnmanagedType (loc);
7321                                 return null;
7322                         }
7323
7324                         type_queried = texpr.Type;
7325
7326                         int size_of = GetTypeSize (type_queried);
7327                         if (size_of > 0) {
7328                                 return new IntConstant (size_of);
7329                         }
7330
7331                         if (!ec.InUnsafe) {
7332                                 Report.Error (233, loc, "'{0}' does not have a predefined size, therefore sizeof can only be used in an unsafe context (consider using System.Runtime.InteropServices.Marshal.SizeOf)",
7333                                          TypeManager.CSharpName (type_queried));
7334                                 return null;
7335                         }
7336
7337                         CheckObsoleteAttribute (type_queried);
7338
7339                         if (!TypeManager.IsUnmanagedType (type_queried)){
7340                                 Report.Error (208, loc, "Cannot take the size of an unmanaged type (" + TypeManager.CSharpName (type_queried) + ")");
7341                                 return null;
7342                         }
7343
7344                         type = TypeManager.int32_type;
7345                         eclass = ExprClass.Value;
7346                         return this;
7347                 }
7348
7349                 public override void Emit (EmitContext ec)
7350                 {
7351                         int size = GetTypeSize (type_queried);
7352
7353                         if (size == 0)
7354                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
7355                         else
7356                                 IntConstant.EmitInt (ec.ig, size);
7357                 }
7358         }
7359
7360         /// <summary>
7361         ///   Implements the member access expression
7362         /// </summary>
7363         public class MemberAccess : Expression {
7364                 public string Identifier;
7365                 protected Expression expr;
7366                 protected TypeArguments args;
7367
7368                 public MemberAccess (Expression expr, string id, Location l)
7369                 {
7370                         this.expr = expr;
7371                         Identifier = id;
7372                         loc = l;
7373                 }
7374
7375                 public MemberAccess (Expression expr, string id, TypeArguments args,
7376                                      Location l)
7377                         : this (expr, id, l)
7378                 {
7379                         this.args = args;
7380                 }
7381
7382                 public Expression Expr {
7383                         get {
7384                                 return expr;
7385                         }
7386                 }
7387
7388                 public virtual Expression DoResolve (EmitContext ec, Expression right_side,
7389                                                      ResolveFlags flags)
7390                 {
7391                         if (type != null)
7392                                 throw new Exception ();
7393
7394                         //
7395                         // Resolve the expression with flow analysis turned off, we'll do the definite
7396                         // assignment checks later.  This is because we don't know yet what the expression
7397                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
7398                         // definite assignment check on the actual field and not on the whole struct.
7399                         //
7400
7401                         SimpleName original = expr as SimpleName;
7402                         expr = expr.Resolve (ec, flags | ResolveFlags.Intermediate | ResolveFlags.DisableFlowAnalysis);
7403                         if (expr == null)
7404                                 return null;
7405
7406                         if (expr is Namespace) {
7407                                 Namespace ns = (Namespace) expr;
7408                                 string lookup_id = MemberName.MakeName (Identifier, args);
7409                                 FullNamedExpression retval = ns.Lookup (ec.DeclSpace, lookup_id, loc);
7410                                 if ((retval != null) && (args != null))
7411                                         retval = new ConstructedType (retval, args, loc).ResolveAsTypeStep (ec);
7412                                 if (retval == null)
7413                                         Report.Error (234, loc, "The type or namespace name `{0}' could not be found in namespace `{1}'", Identifier, ns.FullName);
7414                                 return retval;
7415                         }
7416
7417                         //
7418                         // TODO: I mailed Ravi about this, and apparently we can get rid
7419                         // of this and put it in the right place.
7420                         //
7421                         // Handle enums here when they are in transit.
7422                         // Note that we cannot afford to hit MemberLookup in this case because
7423                         // it will fail to find any members at all
7424                         //
7425
7426                         Type expr_type;
7427                         if (expr is TypeExpr){
7428                                 expr_type = expr.Type;
7429
7430                                 if (!ec.DeclSpace.CheckAccessLevel (expr_type)){
7431                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", expr_type);
7432                                         return null;
7433                                 }
7434
7435                                 if (expr_type == TypeManager.enum_type || expr_type.IsSubclassOf (TypeManager.enum_type)){
7436                                         Enum en = TypeManager.LookupEnum (expr_type);
7437
7438                                         if (en != null) {
7439                                                 object value = en.LookupEnumValue (Identifier, loc);
7440
7441                                                 if (value != null){
7442                                                         MemberCore mc = en.GetDefinition (Identifier);
7443                                                         ObsoleteAttribute oa = mc.GetObsoleteAttribute (en);
7444                                                         if (oa != null) {
7445                                                                 AttributeTester.Report_ObsoleteMessage (oa, mc.GetSignatureForError (), Location);
7446                                                         }
7447                                                         oa = en.GetObsoleteAttribute (en);
7448                                                         if (oa != null) {
7449                                                                 AttributeTester.Report_ObsoleteMessage (oa, en.GetSignatureForError (), Location);
7450                                                         }
7451
7452                                                         Constant c = Constantify (value, en.UnderlyingType);
7453                                                         return new EnumConstant (c, expr_type);
7454                                                 }
7455                                         } else {
7456                                                 CheckObsoleteAttribute (expr_type);
7457
7458                                                 FieldInfo fi = expr_type.GetField (Identifier);
7459                                                 if (fi != null) {
7460                                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (fi);
7461                                                         if (oa != null)
7462                                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (fi), Location);
7463                                                 }
7464                                         }
7465                                 }
7466                         } else
7467                                 expr_type = expr.Type;
7468
7469                         if (expr_type.IsPointer){
7470                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7471                                        TypeManager.CSharpName (expr_type) + ")");
7472                                 return null;
7473                         }
7474
7475                         Expression member_lookup;
7476                         member_lookup = MemberLookup (
7477                                 ec, expr_type, expr_type, Identifier, loc);
7478                         if ((member_lookup == null) && (args != null)) {
7479                                 string lookup_id = MemberName.MakeName (Identifier, args);
7480                                 member_lookup = MemberLookup (
7481                                         ec, expr_type, expr_type, lookup_id, loc);
7482                         }
7483                         if (member_lookup == null) {
7484                                 MemberLookupFailed (
7485                                         ec, expr_type, expr_type, Identifier, null, true, loc);
7486                                 return null;
7487                         }
7488
7489                         if (member_lookup is TypeExpr) {
7490                                 if (!(expr is TypeExpr) &&
7491                                     (original == null || !original.IdenticalNameAndTypeName (ec, expr, loc))) {
7492                                         Error (572, "Can't reference type `" + Identifier + "' through an expression; try `" +
7493                                                member_lookup.Type + "' instead");
7494                                         return null;
7495                                 }
7496
7497                                 return member_lookup;
7498                         }
7499
7500                         MemberExpr me = (MemberExpr) member_lookup;
7501                         member_lookup = me.ResolveMemberAccess (ec, expr, loc, original);
7502                         if (member_lookup == null)
7503                                 return null;
7504
7505                         if (args != null) {
7506                                 MethodGroupExpr mg = member_lookup as MethodGroupExpr;
7507                                 if (mg == null)
7508                                         throw new InternalErrorException ();
7509
7510                                 return mg.ResolveGeneric (ec, args);
7511                         }
7512
7513                         // The following DoResolve/DoResolveLValue will do the definite assignment
7514                         // check.
7515
7516                         if (right_side != null)
7517                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
7518                         else
7519                                 member_lookup = member_lookup.DoResolve (ec);
7520
7521                         return member_lookup;
7522                 }
7523
7524                 public override Expression DoResolve (EmitContext ec)
7525                 {
7526                         return DoResolve (ec, null, ResolveFlags.VariableOrValue | ResolveFlags.Type);
7527                 }
7528
7529                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7530                 {
7531                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue | ResolveFlags.Type);
7532                 }
7533
7534                 public override FullNamedExpression ResolveAsTypeStep (EmitContext ec)
7535                 {
7536                         return ResolveNamespaceOrType (ec, false);
7537                 }
7538
7539                 public FullNamedExpression ResolveNamespaceOrType (EmitContext ec, bool silent)
7540                 {
7541                         FullNamedExpression new_expr = expr.ResolveAsTypeStep (ec);
7542
7543                         if (new_expr == null)
7544                                 return null;
7545
7546                         string lookup_id = MemberName.MakeName (Identifier, args);
7547
7548                         if (new_expr is Namespace) {
7549                                 Namespace ns = (Namespace) new_expr;
7550                                 FullNamedExpression retval = ns.Lookup (ec.DeclSpace, lookup_id, loc);
7551                                 if ((retval != null) && (args != null))
7552                                         retval = new ConstructedType (retval, args, loc).ResolveAsTypeStep (ec);
7553                                 if (!silent && retval == null)
7554                                         Report.Error (234, loc, "The type or namespace name `{0}' could not be found in namespace `{1}'", Identifier, ns.FullName);
7555                                 return retval;
7556                         }
7557
7558                         TypeExpr tnew_expr = new_expr.ResolveAsTypeTerminal (ec);
7559                         if (tnew_expr == null)
7560                                 return null;
7561
7562                         Type expr_type = tnew_expr.Type;
7563
7564                         if (expr_type.IsPointer){
7565                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7566                                        TypeManager.CSharpName (expr_type) + ")");
7567                                 return null;
7568                         }
7569
7570                         Expression member_lookup = MemberLookup (ec, expr_type, expr_type, lookup_id, loc);
7571                         if (member_lookup == null) {
7572                                 int errors = Report.Errors;
7573                                 MemberLookupFailed (ec, expr_type, expr_type, lookup_id, null, false, loc);
7574
7575                                 if (!silent && errors == Report.Errors)
7576                                         Report.Error (234, loc, "The type name `{0}' could not be found in type `{1}'",
7577                                                       lookup_id, new_expr.FullName);
7578                                 return null;
7579                         }
7580
7581                         if (!(member_lookup is TypeExpr)) {
7582                                 Report.Error (118, loc, "'{0}.{1}' denotes a '{2}', where a type was expected",
7583                                               new_expr.FullName, lookup_id, member_lookup.ExprClassName ());
7584                                 return null;
7585                         }
7586
7587                         TypeExpr texpr = member_lookup.ResolveAsTypeTerminal (ec);
7588                         if (texpr == null)
7589                                 return null;
7590
7591                         TypeArguments the_args = args;
7592                         if (TypeManager.HasGenericArguments (expr_type)) {
7593                                 Type[] decl_args = TypeManager.GetTypeArguments (expr_type);
7594
7595                                 TypeArguments new_args = new TypeArguments (loc);
7596                                 foreach (Type decl in decl_args)
7597                                         new_args.Add (new TypeExpression (decl, loc));
7598
7599                                 if (args != null)
7600                                         new_args.Add (args);
7601
7602                                 the_args = new_args;
7603                         }
7604
7605                         if (the_args != null) {
7606                                 ConstructedType ctype = new ConstructedType (texpr.Type, the_args, loc);
7607                                 return ctype.ResolveAsTypeStep (ec);
7608                         }
7609
7610                         return texpr;
7611                 }
7612
7613                 public override void Emit (EmitContext ec)
7614                 {
7615                         throw new Exception ("Should not happen");
7616                 }
7617
7618                 public override string ToString ()
7619                 {
7620                         return expr + "." + MemberName.MakeName (Identifier, args);
7621                 }
7622         }
7623
7624         /// <summary>
7625         ///   Implements checked expressions
7626         /// </summary>
7627         public class CheckedExpr : Expression {
7628
7629                 public Expression Expr;
7630
7631                 public CheckedExpr (Expression e, Location l)
7632                 {
7633                         Expr = e;
7634                         loc = l;
7635                 }
7636
7637                 public override Expression DoResolve (EmitContext ec)
7638                 {
7639                         bool last_check = ec.CheckState;
7640                         bool last_const_check = ec.ConstantCheckState;
7641
7642                         ec.CheckState = true;
7643                         ec.ConstantCheckState = true;
7644                         Expr = Expr.Resolve (ec);
7645                         ec.CheckState = last_check;
7646                         ec.ConstantCheckState = last_const_check;
7647
7648                         if (Expr == null)
7649                                 return null;
7650
7651                         if (Expr is Constant)
7652                                 return Expr;
7653
7654                         eclass = Expr.eclass;
7655                         type = Expr.Type;
7656                         return this;
7657                 }
7658
7659                 public override void Emit (EmitContext ec)
7660                 {
7661                         bool last_check = ec.CheckState;
7662                         bool last_const_check = ec.ConstantCheckState;
7663
7664                         ec.CheckState = true;
7665                         ec.ConstantCheckState = true;
7666                         Expr.Emit (ec);
7667                         ec.CheckState = last_check;
7668                         ec.ConstantCheckState = last_const_check;
7669                 }
7670
7671         }
7672
7673         /// <summary>
7674         ///   Implements the unchecked expression
7675         /// </summary>
7676         public class UnCheckedExpr : Expression {
7677
7678                 public Expression Expr;
7679
7680                 public UnCheckedExpr (Expression e, Location l)
7681                 {
7682                         Expr = e;
7683                         loc = l;
7684                 }
7685
7686                 public override Expression DoResolve (EmitContext ec)
7687                 {
7688                         bool last_check = ec.CheckState;
7689                         bool last_const_check = ec.ConstantCheckState;
7690
7691                         ec.CheckState = false;
7692                         ec.ConstantCheckState = false;
7693                         Expr = Expr.Resolve (ec);
7694                         ec.CheckState = last_check;
7695                         ec.ConstantCheckState = last_const_check;
7696
7697                         if (Expr == null)
7698                                 return null;
7699
7700                         if (Expr is Constant)
7701                                 return Expr;
7702
7703                         eclass = Expr.eclass;
7704                         type = Expr.Type;
7705                         return this;
7706                 }
7707
7708                 public override void Emit (EmitContext ec)
7709                 {
7710                         bool last_check = ec.CheckState;
7711                         bool last_const_check = ec.ConstantCheckState;
7712
7713                         ec.CheckState = false;
7714                         ec.ConstantCheckState = false;
7715                         Expr.Emit (ec);
7716                         ec.CheckState = last_check;
7717                         ec.ConstantCheckState = last_const_check;
7718                 }
7719
7720         }
7721
7722         /// <summary>
7723         ///   An Element Access expression.
7724         ///
7725         ///   During semantic analysis these are transformed into
7726         ///   IndexerAccess, ArrayAccess or a PointerArithmetic.
7727         /// </summary>
7728         public class ElementAccess : Expression {
7729                 public ArrayList  Arguments;
7730                 public Expression Expr;
7731
7732                 public ElementAccess (Expression e, ArrayList e_list, Location l)
7733                 {
7734                         Expr = e;
7735
7736                         loc  = l;
7737
7738                         if (e_list == null)
7739                                 return;
7740
7741                         Arguments = new ArrayList ();
7742                         foreach (Expression tmp in e_list)
7743                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
7744
7745                 }
7746
7747                 bool CommonResolve (EmitContext ec)
7748                 {
7749                         Expr = Expr.Resolve (ec);
7750
7751                         if (Expr == null)
7752                                 return false;
7753
7754                         if (Arguments == null)
7755                                 return false;
7756
7757                         foreach (Argument a in Arguments){
7758                                 if (!a.Resolve (ec, loc))
7759                                         return false;
7760                         }
7761
7762                         return true;
7763                 }
7764
7765                 Expression MakePointerAccess (EmitContext ec, Type t)
7766                 {
7767                         if (t == TypeManager.void_ptr_type){
7768                                 Error (242, "The array index operation is not valid for void pointers");
7769                                 return null;
7770                         }
7771                         if (Arguments.Count != 1){
7772                                 Error (196, "A pointer must be indexed by a single value");
7773                                 return null;
7774                         }
7775                         Expression p;
7776
7777                         p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr, t, loc).Resolve (ec);
7778                         if (p == null)
7779                                 return null;
7780                         return new Indirection (p, loc).Resolve (ec);
7781                 }
7782
7783                 public override Expression DoResolve (EmitContext ec)
7784                 {
7785                         if (!CommonResolve (ec))
7786                                 return null;
7787
7788                         //
7789                         // We perform some simple tests, and then to "split" the emit and store
7790                         // code we create an instance of a different class, and return that.
7791                         //
7792                         // I am experimenting with this pattern.
7793                         //
7794                         Type t = Expr.Type;
7795
7796                         if (t == TypeManager.array_type){
7797                                 Report.Error (21, loc, "Cannot use indexer on System.Array");
7798                                 return null;
7799                         }
7800
7801                         if (t.IsArray)
7802                                 return (new ArrayAccess (this, loc)).Resolve (ec);
7803                         if (t.IsPointer)
7804                                 return MakePointerAccess (ec, Expr.Type);
7805
7806                         FieldExpr fe = Expr as FieldExpr;
7807                         if (fe != null) {
7808                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (fe.FieldInfo);
7809                                 if (ff != null) {
7810                                         return MakePointerAccess (ec, ff.ElementType);
7811                                 }
7812                         }
7813                         return (new IndexerAccess (this, loc)).Resolve (ec);
7814                 }
7815
7816                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7817                 {
7818                         if (!CommonResolve (ec))
7819                                 return null;
7820
7821                         Type t = Expr.Type;
7822                         if (t.IsArray)
7823                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
7824
7825                         if (t.IsPointer)
7826                                 return MakePointerAccess (ec, Expr.Type);
7827
7828                         FieldExpr fe = Expr as FieldExpr;
7829                         if (fe != null) {
7830                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (fe.FieldInfo);
7831                                 if (ff != null) {
7832                                         if (!(fe.InstanceExpression is LocalVariableReference) &&
7833                                                 !(fe.InstanceExpression is This)) {
7834                                                 Error (1708, "Fixed buffers can only be accessed through locals or fields");
7835                                                 return null;
7836                                         }
7837 // TODO: not sure whether it is correct
7838 //                                      if (!ec.InFixedInitializer) {
7839 //                                              Error (1666, "You cannot use fixed sized buffers contained in unfixed expressions. Try using the fixed statement");
7840 //                                              return null;
7841 //                                      }
7842                                         return MakePointerAccess (ec, ff.ElementType);
7843                                 }
7844                         }
7845                         return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
7846                 }
7847
7848                 public override void Emit (EmitContext ec)
7849                 {
7850                         throw new Exception ("Should never be reached");
7851                 }
7852         }
7853
7854         /// <summary>
7855         ///   Implements array access
7856         /// </summary>
7857         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
7858                 //
7859                 // Points to our "data" repository
7860                 //
7861                 ElementAccess ea;
7862
7863                 LocalTemporary temp;
7864                 bool prepared;
7865
7866                 public ArrayAccess (ElementAccess ea_data, Location l)
7867                 {
7868                         ea = ea_data;
7869                         eclass = ExprClass.Variable;
7870                         loc = l;
7871                 }
7872
7873                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7874                 {
7875                         return DoResolve (ec);
7876                 }
7877
7878                 public override Expression DoResolve (EmitContext ec)
7879                 {
7880 #if false
7881                         ExprClass eclass = ea.Expr.eclass;
7882
7883                         // As long as the type is valid
7884                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
7885                               eclass == ExprClass.Value)) {
7886                                 ea.Expr.Error_UnexpectedKind ("variable or value");
7887                                 return null;
7888                         }
7889 #endif
7890
7891                         Type t = ea.Expr.Type;
7892                         if (t.GetArrayRank () != ea.Arguments.Count){
7893                                 ea.Error (22,
7894                                           "Incorrect number of indexes for array " +
7895                                           " expected: " + t.GetArrayRank () + " got: " +
7896                                           ea.Arguments.Count);
7897                                 return null;
7898                         }
7899
7900                         type = TypeManager.GetElementType (t);
7901                         if (type.IsPointer && !ec.InUnsafe){
7902                                 UnsafeError (ea.Location);
7903                                 return null;
7904                         }
7905
7906                         foreach (Argument a in ea.Arguments){
7907                                 Type argtype = a.Type;
7908
7909                                 if (argtype == TypeManager.int32_type ||
7910                                     argtype == TypeManager.uint32_type ||
7911                                     argtype == TypeManager.int64_type ||
7912                                     argtype == TypeManager.uint64_type) {
7913                                         Constant c = a.Expr as Constant;
7914                                         if (c != null && c.IsNegative) {
7915                                                 Report.Warning (251, 2, a.Expr.Location, "Indexing an array with a negative index (array indices always start at zero)");
7916                                         }
7917                                         continue;
7918                                 }
7919
7920                                 //
7921                                 // Mhm.  This is strage, because the Argument.Type is not the same as
7922                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
7923                                 //
7924                                 // Wonder if I will run into trouble for this.
7925                                 //
7926                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
7927                                 if (a.Expr == null)
7928                                         return null;
7929                         }
7930
7931                         eclass = ExprClass.Variable;
7932
7933                         return this;
7934                 }
7935
7936                 /// <summary>
7937                 ///    Emits the right opcode to load an object of Type `t'
7938                 ///    from an array of T
7939                 /// </summary>
7940                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
7941                 {
7942                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
7943                                 ig.Emit (OpCodes.Ldelem_U1);
7944                         else if (type == TypeManager.sbyte_type)
7945                                 ig.Emit (OpCodes.Ldelem_I1);
7946                         else if (type == TypeManager.short_type)
7947                                 ig.Emit (OpCodes.Ldelem_I2);
7948                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
7949                                 ig.Emit (OpCodes.Ldelem_U2);
7950                         else if (type == TypeManager.int32_type)
7951                                 ig.Emit (OpCodes.Ldelem_I4);
7952                         else if (type == TypeManager.uint32_type)
7953                                 ig.Emit (OpCodes.Ldelem_U4);
7954                         else if (type == TypeManager.uint64_type)
7955                                 ig.Emit (OpCodes.Ldelem_I8);
7956                         else if (type == TypeManager.int64_type)
7957                                 ig.Emit (OpCodes.Ldelem_I8);
7958                         else if (type == TypeManager.float_type)
7959                                 ig.Emit (OpCodes.Ldelem_R4);
7960                         else if (type == TypeManager.double_type)
7961                                 ig.Emit (OpCodes.Ldelem_R8);
7962                         else if (type == TypeManager.intptr_type)
7963                                 ig.Emit (OpCodes.Ldelem_I);
7964                         else if (TypeManager.IsEnumType (type)){
7965                                 EmitLoadOpcode (ig, TypeManager.EnumToUnderlying (type));
7966                         } else if (type.IsValueType){
7967                                 ig.Emit (OpCodes.Ldelema, type);
7968                                 ig.Emit (OpCodes.Ldobj, type);
7969                         } else if (type.IsGenericParameter)
7970                                 ig.Emit (OpCodes.Ldelem_Any, type);
7971                         else
7972                                 ig.Emit (OpCodes.Ldelem_Ref);
7973                 }
7974
7975                 /// <summary>
7976                 ///    Returns the right opcode to store an object of Type `t'
7977                 ///    from an array of T.
7978                 /// </summary>
7979                 static public OpCode GetStoreOpcode (Type t, out bool is_stobj, out bool has_type_arg)
7980                 {
7981                         //Console.WriteLine (new System.Diagnostics.StackTrace ());
7982                         has_type_arg = false; is_stobj = false;
7983                         t = TypeManager.TypeToCoreType (t);
7984                         if (TypeManager.IsEnumType (t))
7985                                 t = TypeManager.EnumToUnderlying (t);
7986                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
7987                             t == TypeManager.bool_type)
7988                                 return OpCodes.Stelem_I1;
7989                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type ||
7990                                  t == TypeManager.char_type)
7991                                 return OpCodes.Stelem_I2;
7992                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
7993                                 return OpCodes.Stelem_I4;
7994                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
7995                                 return OpCodes.Stelem_I8;
7996                         else if (t == TypeManager.float_type)
7997                                 return OpCodes.Stelem_R4;
7998                         else if (t == TypeManager.double_type)
7999                                 return OpCodes.Stelem_R8;
8000                         else if (t == TypeManager.intptr_type) {
8001                                 has_type_arg = true;
8002                                 is_stobj = true;
8003                                 return OpCodes.Stobj;
8004                         } else if (t.IsValueType) {
8005                                 has_type_arg = true;
8006                                 is_stobj = true;
8007                                 return OpCodes.Stobj;
8008                         } else if (t.IsGenericParameter) {
8009                                 has_type_arg = true;
8010                                 return OpCodes.Stelem_Any;
8011                         } else
8012                                 return OpCodes.Stelem_Ref;
8013                 }
8014
8015                 MethodInfo FetchGetMethod ()
8016                 {
8017                         ModuleBuilder mb = CodeGen.Module.Builder;
8018                         int arg_count = ea.Arguments.Count;
8019                         Type [] args = new Type [arg_count];
8020                         MethodInfo get;
8021
8022                         for (int i = 0; i < arg_count; i++){
8023                                 //args [i++] = a.Type;
8024                                 args [i] = TypeManager.int32_type;
8025                         }
8026
8027                         get = mb.GetArrayMethod (
8028                                 ea.Expr.Type, "Get",
8029                                 CallingConventions.HasThis |
8030                                 CallingConventions.Standard,
8031                                 type, args);
8032                         return get;
8033                 }
8034
8035
8036                 MethodInfo FetchAddressMethod ()
8037                 {
8038                         ModuleBuilder mb = CodeGen.Module.Builder;
8039                         int arg_count = ea.Arguments.Count;
8040                         Type [] args = new Type [arg_count];
8041                         MethodInfo address;
8042                         Type ret_type;
8043
8044                         ret_type = TypeManager.GetReferenceType (type);
8045
8046                         for (int i = 0; i < arg_count; i++){
8047                                 //args [i++] = a.Type;
8048                                 args [i] = TypeManager.int32_type;
8049                         }
8050
8051                         address = mb.GetArrayMethod (
8052                                 ea.Expr.Type, "Address",
8053                                 CallingConventions.HasThis |
8054                                 CallingConventions.Standard,
8055                                 ret_type, args);
8056
8057                         return address;
8058                 }
8059
8060                 //
8061                 // Load the array arguments into the stack.
8062                 //
8063                 // If we have been requested to cache the values (cached_locations array
8064                 // initialized), then load the arguments the first time and store them
8065                 // in locals.  otherwise load from local variables.
8066                 //
8067                 void LoadArrayAndArguments (EmitContext ec)
8068                 {
8069                         ILGenerator ig = ec.ig;
8070
8071                         ea.Expr.Emit (ec);
8072                         foreach (Argument a in ea.Arguments){
8073                                 Type argtype = a.Expr.Type;
8074
8075                                 a.Expr.Emit (ec);
8076
8077                                 if (argtype == TypeManager.int64_type)
8078                                         ig.Emit (OpCodes.Conv_Ovf_I);
8079                                 else if (argtype == TypeManager.uint64_type)
8080                                         ig.Emit (OpCodes.Conv_Ovf_I_Un);
8081                         }
8082                 }
8083
8084                 public void Emit (EmitContext ec, bool leave_copy)
8085                 {
8086                         int rank = ea.Expr.Type.GetArrayRank ();
8087                         ILGenerator ig = ec.ig;
8088
8089                         if (!prepared) {
8090                                 LoadArrayAndArguments (ec);
8091
8092                                 if (rank == 1)
8093                                         EmitLoadOpcode (ig, type);
8094                                 else {
8095                                         MethodInfo method;
8096
8097                                         method = FetchGetMethod ();
8098                                         ig.Emit (OpCodes.Call, method);
8099                                 }
8100                         } else
8101                                 LoadFromPtr (ec.ig, this.type);
8102
8103                         if (leave_copy) {
8104                                 ec.ig.Emit (OpCodes.Dup);
8105                                 temp = new LocalTemporary (ec, this.type);
8106                                 temp.Store (ec);
8107                         }
8108                 }
8109
8110                 public override void Emit (EmitContext ec)
8111                 {
8112                         Emit (ec, false);
8113                 }
8114
8115                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8116                 {
8117                         int rank = ea.Expr.Type.GetArrayRank ();
8118                         ILGenerator ig = ec.ig;
8119                         Type t = source.Type;
8120                         prepared = prepare_for_load;
8121
8122                         if (prepare_for_load) {
8123                                 AddressOf (ec, AddressOp.LoadStore);
8124                                 ec.ig.Emit (OpCodes.Dup);
8125                                 source.Emit (ec);
8126                                 if (leave_copy) {
8127                                         ec.ig.Emit (OpCodes.Dup);
8128                                         temp = new LocalTemporary (ec, this.type);
8129                                         temp.Store (ec);
8130                                 }
8131                                 StoreFromPtr (ec.ig, t);
8132
8133                                 if (temp != null)
8134                                         temp.Emit (ec);
8135
8136                                 return;
8137                         }
8138
8139                         LoadArrayAndArguments (ec);
8140
8141                         if (rank == 1) {
8142                                 bool is_stobj, has_type_arg;
8143                                 OpCode op = GetStoreOpcode (t, out is_stobj, out has_type_arg);
8144
8145                                 //
8146                                 // The stobj opcode used by value types will need
8147                                 // an address on the stack, not really an array/array
8148                                 // pair
8149                                 //
8150                                 if (is_stobj)
8151                                         ig.Emit (OpCodes.Ldelema, t);
8152
8153                                 source.Emit (ec);
8154                                 if (leave_copy) {
8155                                         ec.ig.Emit (OpCodes.Dup);
8156                                         temp = new LocalTemporary (ec, this.type);
8157                                         temp.Store (ec);
8158                                 }
8159
8160                                 if (is_stobj)
8161                                         ig.Emit (OpCodes.Stobj, t);
8162                                 else if (has_type_arg)
8163                                         ig.Emit (op, t);
8164                                 else
8165                                         ig.Emit (op);
8166                         } else {
8167                                 ModuleBuilder mb = CodeGen.Module.Builder;
8168                                 int arg_count = ea.Arguments.Count;
8169                                 Type [] args = new Type [arg_count + 1];
8170                                 MethodInfo set;
8171
8172                                 source.Emit (ec);
8173                                 if (leave_copy) {
8174                                         ec.ig.Emit (OpCodes.Dup);
8175                                         temp = new LocalTemporary (ec, this.type);
8176                                         temp.Store (ec);
8177                                 }
8178
8179                                 for (int i = 0; i < arg_count; i++){
8180                                         //args [i++] = a.Type;
8181                                         args [i] = TypeManager.int32_type;
8182                                 }
8183
8184                                 args [arg_count] = type;
8185
8186                                 set = mb.GetArrayMethod (
8187                                         ea.Expr.Type, "Set",
8188                                         CallingConventions.HasThis |
8189                                         CallingConventions.Standard,
8190                                         TypeManager.void_type, args);
8191
8192                                 ig.Emit (OpCodes.Call, set);
8193                         }
8194
8195                         if (temp != null)
8196                                 temp.Emit (ec);
8197                 }
8198
8199                 public void AddressOf (EmitContext ec, AddressOp mode)
8200                 {
8201                         int rank = ea.Expr.Type.GetArrayRank ();
8202                         ILGenerator ig = ec.ig;
8203
8204                         LoadArrayAndArguments (ec);
8205
8206                         if (rank == 1){
8207                                 ig.Emit (OpCodes.Ldelema, type);
8208                         } else {
8209                                 MethodInfo address = FetchAddressMethod ();
8210                                 ig.Emit (OpCodes.Call, address);
8211                         }
8212                 }
8213
8214                 public void EmitGetLength (EmitContext ec, int dim)
8215                 {
8216                         int rank = ea.Expr.Type.GetArrayRank ();
8217                         ILGenerator ig = ec.ig;
8218
8219                         ea.Expr.Emit (ec);
8220                         if (rank == 1) {
8221                                 ig.Emit (OpCodes.Ldlen);
8222                                 ig.Emit (OpCodes.Conv_I4);
8223                         } else {
8224                                 IntLiteral.EmitInt (ig, dim);
8225                                 ig.Emit (OpCodes.Callvirt, TypeManager.int_getlength_int);
8226                         }
8227                 }
8228         }
8229
8230         class Indexers {
8231                 public ArrayList Properties;
8232                 static Hashtable map;
8233
8234                 public struct Indexer {
8235                         public readonly Type Type;
8236                         public readonly MethodInfo Getter, Setter;
8237
8238                         public Indexer (Type type, MethodInfo get, MethodInfo set)
8239                         {
8240                                 this.Type = type;
8241                                 this.Getter = get;
8242                                 this.Setter = set;
8243                         }
8244                 }
8245
8246                 static Indexers ()
8247                 {
8248                         map = new Hashtable ();
8249                 }
8250
8251                 Indexers ()
8252                 {
8253                         Properties = new ArrayList ();
8254                 }
8255
8256                 void Append (MemberInfo [] mi)
8257                 {
8258                         foreach (PropertyInfo property in mi){
8259                                 MethodInfo get, set;
8260
8261                                 get = property.GetGetMethod (true);
8262                                 set = property.GetSetMethod (true);
8263                                 Properties.Add (new Indexer (property.PropertyType, get, set));
8264                         }
8265                 }
8266
8267                 static private MemberInfo [] GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
8268                 {
8269                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
8270
8271                         MemberInfo [] mi = TypeManager.MemberLookup (
8272                                 caller_type, caller_type, lookup_type, MemberTypes.Property,
8273                                 BindingFlags.Public | BindingFlags.Instance |
8274                                 BindingFlags.DeclaredOnly, p_name, null);
8275
8276                         if (mi == null || mi.Length == 0)
8277                                 return null;
8278
8279                         return mi;
8280                 }
8281
8282                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
8283                 {
8284                         Indexers ix = (Indexers) map [lookup_type];
8285
8286                         if (ix != null)
8287                                 return ix;
8288
8289                         Type copy = lookup_type;
8290                         while (copy != TypeManager.object_type && copy != null){
8291                                 MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, copy);
8292
8293                                 if (mi != null){
8294                                         if (ix == null)
8295                                                 ix = new Indexers ();
8296
8297                                         ix.Append (mi);
8298                                 }
8299
8300                                 copy = copy.BaseType;
8301                         }
8302
8303                         if (!lookup_type.IsInterface)
8304                                 return ix;
8305
8306                         Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
8307                         if (ifaces != null) {
8308                                 foreach (Type itype in ifaces) {
8309                                         MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, itype);
8310                                         if (mi != null){
8311                                                 if (ix == null)
8312                                                         ix = new Indexers ();
8313
8314                                                 ix.Append (mi);
8315                                         }
8316                                 }
8317                         }
8318
8319                         return ix;
8320                 }
8321         }
8322
8323         /// <summary>
8324         ///   Expressions that represent an indexer call.
8325         /// </summary>
8326         public class IndexerAccess : Expression, IAssignMethod {
8327                 //
8328                 // Points to our "data" repository
8329                 //
8330                 MethodInfo get, set;
8331                 ArrayList set_arguments;
8332                 bool is_base_indexer;
8333
8334                 protected Type indexer_type;
8335                 protected Type current_type;
8336                 protected Expression instance_expr;
8337                 protected ArrayList arguments;
8338
8339                 public IndexerAccess (ElementAccess ea, Location loc)
8340                         : this (ea.Expr, false, loc)
8341                 {
8342                         this.arguments = ea.Arguments;
8343                 }
8344
8345                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
8346                                          Location loc)
8347                 {
8348                         this.instance_expr = instance_expr;
8349                         this.is_base_indexer = is_base_indexer;
8350                         this.eclass = ExprClass.Value;
8351                         this.loc = loc;
8352                 }
8353
8354                 protected virtual bool CommonResolve (EmitContext ec)
8355                 {
8356                         indexer_type = instance_expr.Type;
8357                         current_type = ec.ContainerType;
8358
8359                         return true;
8360                 }
8361
8362                 public override Expression DoResolve (EmitContext ec)
8363                 {
8364                         ArrayList AllGetters = new ArrayList();
8365                         if (!CommonResolve (ec))
8366                                 return null;
8367
8368                         //
8369                         // Step 1: Query for all `Item' *properties*.  Notice
8370                         // that the actual methods are pointed from here.
8371                         //
8372                         // This is a group of properties, piles of them.
8373
8374                         bool found_any = false, found_any_getters = false;
8375                         Type lookup_type = indexer_type;
8376
8377                         Indexers ilist;
8378                         ilist = Indexers.GetIndexersForType (current_type, lookup_type, loc);
8379                         if (ilist != null) {
8380                                 found_any = true;
8381                                 if (ilist.Properties != null) {
8382                                         foreach (Indexers.Indexer ix in ilist.Properties) {
8383                                                 if (ix.Getter != null)
8384                                                         AllGetters.Add(ix.Getter);
8385                                         }
8386                                 }
8387                         }
8388
8389                         if (AllGetters.Count > 0) {
8390                                 found_any_getters = true;
8391                                 get = (MethodInfo) Invocation.OverloadResolve (
8392                                         ec, new MethodGroupExpr (AllGetters, loc),
8393                                         arguments, false, loc);
8394                         }
8395
8396                         if (!found_any) {
8397                                 Report.Error (21, loc,
8398                                               "Type `" + TypeManager.CSharpName (indexer_type) +
8399                                               "' does not have any indexers defined");
8400                                 return null;
8401                         }
8402
8403                         if (!found_any_getters) {
8404                                 Error (154, "indexer can not be used in this context, because " +
8405                                        "it lacks a `get' accessor");
8406                                 return null;
8407                         }
8408
8409                         if (get == null) {
8410                                 Error (1501, "No Overload for method `this' takes `" +
8411                                        arguments.Count + "' arguments");
8412                                 return null;
8413                         }
8414
8415                         //
8416                         // Only base will allow this invocation to happen.
8417                         //
8418                         if (get.IsAbstract && this is BaseIndexerAccess){
8419                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (get));
8420                                 return null;
8421                         }
8422
8423                         type = get.ReturnType;
8424                         if (type.IsPointer && !ec.InUnsafe){
8425                                 UnsafeError (loc);
8426                                 return null;
8427                         }
8428
8429                         instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
8430
8431                         eclass = ExprClass.IndexerAccess;
8432                         return this;
8433                 }
8434
8435                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8436                 {
8437                         ArrayList AllSetters = new ArrayList();
8438                         if (!CommonResolve (ec))
8439                                 return null;
8440
8441                         bool found_any = false, found_any_setters = false;
8442
8443                         Indexers ilist = Indexers.GetIndexersForType (current_type, indexer_type, loc);
8444                         if (ilist != null) {
8445                                 found_any = true;
8446                                 if (ilist.Properties != null) {
8447                                         foreach (Indexers.Indexer ix in ilist.Properties) {
8448                                                 if (ix.Setter != null)
8449                                                         AllSetters.Add(ix.Setter);
8450                                         }
8451                                 }
8452                         }
8453                         if (AllSetters.Count > 0) {
8454                                 found_any_setters = true;
8455                                 set_arguments = (ArrayList) arguments.Clone ();
8456                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
8457                                 set = (MethodInfo) Invocation.OverloadResolve (
8458                                         ec, new MethodGroupExpr (AllSetters, loc),
8459                                         set_arguments, false, loc);
8460                         }
8461
8462                         if (!found_any) {
8463                                 Report.Error (21, loc,
8464                                               "Type `" + TypeManager.CSharpName (indexer_type) +
8465                                               "' does not have any indexers defined");
8466                                 return null;
8467                         }
8468
8469                         if (!found_any_setters) {
8470                                 Error (154, "indexer can not be used in this context, because " +
8471                                        "it lacks a `set' accessor");
8472                                 return null;
8473                         }
8474
8475                         if (set == null) {
8476                                 Error (1501, "No Overload for method `this' takes `" +
8477                                        arguments.Count + "' arguments");
8478                                 return null;
8479                         }
8480
8481                         //
8482                         // Only base will allow this invocation to happen.
8483                         //
8484                         if (set.IsAbstract && this is BaseIndexerAccess){
8485                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (set));
8486                                 return null;
8487                         }
8488
8489                         //
8490                         // Now look for the actual match in the list of indexers to set our "return" type
8491                         //
8492                         type = TypeManager.void_type;   // default value
8493                         foreach (Indexers.Indexer ix in ilist.Properties){
8494                                 if (ix.Setter == set){
8495                                         type = ix.Type;
8496                                         break;
8497                                 }
8498                         }
8499
8500                         instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
8501
8502                         eclass = ExprClass.IndexerAccess;
8503                         return this;
8504                 }
8505
8506                 bool prepared = false;
8507                 LocalTemporary temp;
8508
8509                 public void Emit (EmitContext ec, bool leave_copy)
8510                 {
8511                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, get, arguments, loc, prepared, false);
8512                         if (leave_copy) {
8513                                 ec.ig.Emit (OpCodes.Dup);
8514                                 temp = new LocalTemporary (ec, Type);
8515                                 temp.Store (ec);
8516                         }
8517                 }
8518
8519                 //
8520                 // source is ignored, because we already have a copy of it from the
8521                 // LValue resolution and we have already constructed a pre-cached
8522                 // version of the arguments (ea.set_arguments);
8523                 //
8524                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8525                 {
8526                         prepared = prepare_for_load;
8527                         Argument a = (Argument) set_arguments [set_arguments.Count - 1];
8528
8529                         if (prepared) {
8530                                 source.Emit (ec);
8531                                 if (leave_copy) {
8532                                         ec.ig.Emit (OpCodes.Dup);
8533                                         temp = new LocalTemporary (ec, Type);
8534                                         temp.Store (ec);
8535                                 }
8536                         } else if (leave_copy) {
8537                                 temp = new LocalTemporary (ec, Type);
8538                                 source.Emit (ec);
8539                                 temp.Store (ec);
8540                                 a.Expr = temp;
8541                         }
8542
8543                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, set, set_arguments, loc, false, prepared);
8544
8545                         if (temp != null)
8546                                 temp.Emit (ec);
8547                 }
8548
8549
8550                 public override void Emit (EmitContext ec)
8551                 {
8552                         Emit (ec, false);
8553                 }
8554         }
8555
8556         /// <summary>
8557         ///   The base operator for method names
8558         /// </summary>
8559         public class BaseAccess : Expression {
8560                 string member;
8561
8562                 public BaseAccess (string member, Location l)
8563                 {
8564                         this.member = member;
8565                         loc = l;
8566                 }
8567
8568                 public override Expression DoResolve (EmitContext ec)
8569                 {
8570                         Expression c = CommonResolve (ec);
8571
8572                         if (c == null)
8573                                 return null;
8574
8575                         //
8576                         // MethodGroups use this opportunity to flag an error on lacking ()
8577                         //
8578                         if (!(c is MethodGroupExpr))
8579                                 return c.Resolve (ec);
8580                         return c;
8581                 }
8582
8583                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8584                 {
8585                         Expression c = CommonResolve (ec);
8586
8587                         if (c == null)
8588                                 return null;
8589
8590                         //
8591                         // MethodGroups use this opportunity to flag an error on lacking ()
8592                         //
8593                         if (! (c is MethodGroupExpr))
8594                                 return c.DoResolveLValue (ec, right_side);
8595
8596                         return c;
8597                 }
8598
8599                 Expression CommonResolve (EmitContext ec)
8600                 {
8601                         Expression member_lookup;
8602                         Type current_type = ec.ContainerType;
8603                         Type base_type = current_type.BaseType;
8604
8605                         if (ec.IsStatic){
8606                                 Error (1511, "Keyword base is not allowed in static method");
8607                                 return null;
8608                         }
8609
8610                         if (ec.IsFieldInitializer){
8611                                 Error (1512, "Keyword base is not available in the current context");
8612                                 return null;
8613                         }
8614
8615                         member_lookup = MemberLookup (ec, ec.ContainerType, null, base_type,
8616                                                       member, AllMemberTypes, AllBindingFlags,
8617                                                       loc);
8618                         if (member_lookup == null) {
8619                                 MemberLookupFailed (ec, base_type, base_type, member, null, true, loc);
8620                                 return null;
8621                         }
8622
8623                         Expression left;
8624
8625                         if (ec.IsStatic)
8626                                 left = new TypeExpression (base_type, loc);
8627                         else
8628                                 left = ec.GetThis (loc);
8629
8630                         MemberExpr me = (MemberExpr) member_lookup;
8631
8632                         Expression e = me.ResolveMemberAccess (ec, left, loc, null);
8633
8634                         if (e is PropertyExpr) {
8635                                 PropertyExpr pe = (PropertyExpr) e;
8636
8637                                 pe.IsBase = true;
8638                         }
8639
8640                         if (e is MethodGroupExpr)
8641                                 ((MethodGroupExpr) e).IsBase = true;
8642
8643                         return e;
8644                 }
8645
8646                 public override void Emit (EmitContext ec)
8647                 {
8648                         throw new Exception ("Should never be called");
8649                 }
8650         }
8651
8652         /// <summary>
8653         ///   The base indexer operator
8654         /// </summary>
8655         public class BaseIndexerAccess : IndexerAccess {
8656                 public BaseIndexerAccess (ArrayList args, Location loc)
8657                         : base (null, true, loc)
8658                 {
8659                         arguments = new ArrayList ();
8660                         foreach (Expression tmp in args)
8661                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
8662                 }
8663
8664                 protected override bool CommonResolve (EmitContext ec)
8665                 {
8666                         instance_expr = ec.GetThis (loc);
8667
8668                         current_type = ec.ContainerType.BaseType;
8669                         indexer_type = current_type;
8670
8671                         foreach (Argument a in arguments){
8672                                 if (!a.Resolve (ec, loc))
8673                                         return false;
8674                         }
8675
8676                         return true;
8677                 }
8678         }
8679
8680         /// <summary>
8681         ///   This class exists solely to pass the Type around and to be a dummy
8682         ///   that can be passed to the conversion functions (this is used by
8683         ///   foreach implementation to typecast the object return value from
8684         ///   get_Current into the proper type.  All code has been generated and
8685         ///   we only care about the side effect conversions to be performed
8686         ///
8687         ///   This is also now used as a placeholder where a no-action expression
8688         ///   is needed (the `New' class).
8689         /// </summary>
8690         public class EmptyExpression : Expression {
8691                 public static readonly EmptyExpression Null = new EmptyExpression ();
8692
8693                 // TODO: should be protected
8694                 public EmptyExpression ()
8695                 {
8696                         type = TypeManager.object_type;
8697                         eclass = ExprClass.Value;
8698                         loc = Location.Null;
8699                 }
8700
8701                 public EmptyExpression (Type t)
8702                 {
8703                         type = t;
8704                         eclass = ExprClass.Value;
8705                         loc = Location.Null;
8706                 }
8707
8708                 public override Expression DoResolve (EmitContext ec)
8709                 {
8710                         return this;
8711                 }
8712
8713                 public override void Emit (EmitContext ec)
8714                 {
8715                         // nothing, as we only exist to not do anything.
8716                 }
8717
8718                 //
8719                 // This is just because we might want to reuse this bad boy
8720                 // instead of creating gazillions of EmptyExpressions.
8721                 // (CanImplicitConversion uses it)
8722                 //
8723                 public void SetType (Type t)
8724                 {
8725                         type = t;
8726                 }
8727         }
8728
8729         public class UserCast : Expression {
8730                 MethodBase method;
8731                 Expression source;
8732
8733                 public UserCast (MethodInfo method, Expression source, Location l)
8734                 {
8735                         this.method = method;
8736                         this.source = source;
8737                         type = method.ReturnType;
8738                         eclass = ExprClass.Value;
8739                         loc = l;
8740                 }
8741
8742                 public Expression Source {
8743                         get {
8744                                 return source;
8745                         }
8746                 }
8747
8748                 public override Expression DoResolve (EmitContext ec)
8749                 {
8750                         //
8751                         // We are born fully resolved
8752                         //
8753                         return this;
8754                 }
8755
8756                 public override void Emit (EmitContext ec)
8757                 {
8758                         ILGenerator ig = ec.ig;
8759
8760                         source.Emit (ec);
8761
8762                         if (method is MethodInfo)
8763                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
8764                         else
8765                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
8766
8767                 }
8768         }
8769
8770         // <summary>
8771         //   This class is used to "construct" the type during a typecast
8772         //   operation.  Since the Type.GetType class in .NET can parse
8773         //   the type specification, we just use this to construct the type
8774         //   one bit at a time.
8775         // </summary>
8776         public class ComposedCast : TypeExpr {
8777                 Expression left;
8778                 string dim;
8779
8780                 public ComposedCast (Expression left, string dim, Location l)
8781                 {
8782                         this.left = left;
8783                         this.dim = dim;
8784                         loc = l;
8785                 }
8786
8787                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
8788                 {
8789                         TypeExpr lexpr = left.ResolveAsTypeTerminal (ec);
8790                         if (lexpr == null)
8791                                 return null;
8792
8793                         Type ltype = lexpr.Type;
8794
8795                         if ((ltype == TypeManager.void_type) && (dim != "*")) {
8796                                 Report.Error (1547, Location,
8797                                               "Keyword 'void' cannot be used in this context");
8798                                 return null;
8799                         }
8800
8801                         if ((dim.Length > 0) && (dim [0] == '?')) {
8802                                 TypeExpr nullable = new NullableType (left, loc);
8803                                 if (dim.Length > 1)
8804                                         nullable = new ComposedCast (nullable, dim.Substring (1), loc);
8805                                 return nullable.ResolveAsTypeTerminal (ec);
8806                         }
8807
8808                         if (dim == "*" && !TypeManager.IsUnmanagedType (ltype)) {
8809                                 Report.Error (208, loc, "Cannot declare a pointer to a managed type ('{0}')", ltype);
8810                                 return null;
8811                         }
8812
8813                         if (dim != "")
8814                                 type = TypeManager.GetConstructedType (ltype, dim);
8815                         else
8816                                 type = ltype;
8817
8818                         if (type == null) {
8819                                 throw new InternalErrorException ("Couldn't create computed type " + ltype + dim);
8820                         }
8821
8822                         if (!ec.InUnsafe && type.IsPointer){
8823                                 UnsafeError (loc);
8824                                 return null;
8825                         }
8826
8827                         if (type.IsArray && (type.GetElementType () == TypeManager.arg_iterator_type ||
8828                                 type.GetElementType () == TypeManager.typed_reference_type)) {
8829                                 Report.Error (611, loc, "Array elements cannot be of type '{0}'", TypeManager.CSharpName (type.GetElementType ()));
8830                                 return null;
8831                         }
8832
8833                         eclass = ExprClass.Type;
8834                         return this;
8835                 }
8836
8837                 public override string Name {
8838                         get {
8839                                 return left + dim;
8840                         }
8841                 }
8842
8843                 public override string FullName {
8844                         get {
8845                                 return type.FullName;
8846                         }
8847                 }
8848         }
8849
8850         public class FixedBufferPtr: Expression {
8851                 Expression array;
8852
8853                 public FixedBufferPtr (Expression array, Type array_type, Location l)
8854                 {
8855                         this.array = array;
8856                         this.loc = l;
8857
8858                         type = TypeManager.GetPointerType (array_type);
8859                         eclass = ExprClass.Value;
8860                 }
8861
8862                 public override void Emit(EmitContext ec)
8863                 {
8864                         array.Emit (ec);
8865                 }
8866
8867                 public override Expression DoResolve (EmitContext ec)
8868                 {
8869                         //
8870                         // We are born fully resolved
8871                         //
8872                         return this;
8873                 }
8874         }
8875
8876
8877         //
8878         // This class is used to represent the address of an array, used
8879         // only by the Fixed statement, this generates "&a [0]" construct
8880         // for fixed (char *pa = a)
8881         //
8882         public class ArrayPtr : FixedBufferPtr {
8883                 Type array_type;
8884
8885                 public ArrayPtr (Expression array, Type array_type, Location l):
8886                         base (array, array_type, l)
8887                 {
8888                         this.array_type = array_type;
8889                 }
8890
8891                 public override void Emit (EmitContext ec)
8892                 {
8893                         base.Emit (ec);
8894
8895                         ILGenerator ig = ec.ig;
8896                         IntLiteral.EmitInt (ig, 0);
8897                         ig.Emit (OpCodes.Ldelema, array_type);
8898                 }
8899         }
8900
8901         //
8902         // Used by the fixed statement
8903         //
8904         public class StringPtr : Expression {
8905                 LocalBuilder b;
8906
8907                 public StringPtr (LocalBuilder b, Location l)
8908                 {
8909                         this.b = b;
8910                         eclass = ExprClass.Value;
8911                         type = TypeManager.char_ptr_type;
8912                         loc = l;
8913                 }
8914
8915                 public override Expression DoResolve (EmitContext ec)
8916                 {
8917                         // This should never be invoked, we are born in fully
8918                         // initialized state.
8919
8920                         return this;
8921                 }
8922
8923                 public override void Emit (EmitContext ec)
8924                 {
8925                         ILGenerator ig = ec.ig;
8926
8927                         ig.Emit (OpCodes.Ldloc, b);
8928                         ig.Emit (OpCodes.Conv_I);
8929                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
8930                         ig.Emit (OpCodes.Add);
8931                 }
8932         }
8933
8934         //
8935         // Implements the `stackalloc' keyword
8936         //
8937         public class StackAlloc : Expression {
8938                 Type otype;
8939                 Expression t;
8940                 Expression count;
8941
8942                 public StackAlloc (Expression type, Expression count, Location l)
8943                 {
8944                         t = type;
8945                         this.count = count;
8946                         loc = l;
8947                 }
8948
8949                 public override Expression DoResolve (EmitContext ec)
8950                 {
8951                         count = count.Resolve (ec);
8952                         if (count == null)
8953                                 return null;
8954
8955                         if (count.Type != TypeManager.int32_type){
8956                                 count = Convert.ImplicitConversionRequired (ec, count, TypeManager.int32_type, loc);
8957                                 if (count == null)
8958                                         return null;
8959                         }
8960
8961                         Constant c = count as Constant;
8962                         if (c != null && c.IsNegative) {
8963                                 Report.Error (247, loc, "Cannot use a negative size with stackalloc");
8964                                 return null;
8965                         }
8966
8967                         if (ec.InCatch || ec.InFinally) {
8968                                 Error (255,
8969                                               "stackalloc can not be used in a catch or finally block");
8970                                 return null;
8971                         }
8972
8973                         TypeExpr texpr = t.ResolveAsTypeTerminal (ec);
8974                         if (texpr == null)
8975                                 return null;
8976
8977                         otype = texpr.Type;
8978
8979                         if (!TypeManager.VerifyUnManaged (otype, loc))
8980                                 return null;
8981
8982                         type = TypeManager.GetPointerType (otype);
8983                         eclass = ExprClass.Value;
8984
8985                         return this;
8986                 }
8987
8988                 public override void Emit (EmitContext ec)
8989                 {
8990                         int size = GetTypeSize (otype);
8991                         ILGenerator ig = ec.ig;
8992
8993                         if (size == 0)
8994                                 ig.Emit (OpCodes.Sizeof, otype);
8995                         else
8996                                 IntConstant.EmitInt (ig, size);
8997                         count.Emit (ec);
8998                         ig.Emit (OpCodes.Mul);
8999                         ig.Emit (OpCodes.Localloc);
9000                 }
9001         }
9002 }