mcs/mcs/expression.cs

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