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 sense 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                         // Dead code optimalization
3533                         if (expr is BoolConstant){
3534                                 BoolConstant bc = (BoolConstant) expr;
3535
3536                                 Report.Warning (429, 4, bc.Value ? falseExpr.Location : trueExpr.Location, "Unreachable expression code detected");
3537                                 return bc.Value ? trueExpr : falseExpr;
3538                         }
3539
3540                         return this;
3541                 }
3542
3543                 public override void Emit (EmitContext ec)
3544                 {
3545                         ILGenerator ig = ec.ig;
3546                         Label false_target = ig.DefineLabel ();
3547                         Label end_target = ig.DefineLabel ();
3548
3549                         expr.EmitBranchable (ec, false_target, false);
3550                         trueExpr.Emit (ec);
3551                         ig.Emit (OpCodes.Br, end_target);
3552                         ig.MarkLabel (false_target);
3553                         falseExpr.Emit (ec);
3554                         ig.MarkLabel (end_target);
3555                 }
3556
3557         }
3558
3559         /// <summary>
3560         ///   Local variables
3561         /// </summary>
3562         public class LocalVariableReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
3563                 public readonly string Name;
3564                 public readonly Block Block;
3565                 public LocalInfo local_info;
3566                 bool is_readonly;
3567                 bool prepared;
3568                 LocalTemporary temp;
3569
3570                 public LocalVariableReference (Block block, string name, Location l)
3571                 {
3572                         Block = block;
3573                         Name = name;
3574                         loc = l;
3575                         eclass = ExprClass.Variable;
3576                 }
3577
3578                 //
3579                 // Setting `is_readonly' to false will allow you to create a writable
3580                 // reference to a read-only variable.  This is used by foreach and using.
3581                 //
3582                 public LocalVariableReference (Block block, string name, Location l,
3583                                                LocalInfo local_info, bool is_readonly)
3584                         : this (block, name, l)
3585                 {
3586                         this.local_info = local_info;
3587                         this.is_readonly = is_readonly;
3588                 }
3589
3590                 public VariableInfo VariableInfo {
3591                         get {
3592                                 return local_info.VariableInfo;
3593                         }
3594                 }
3595
3596                 public bool IsReadOnly {
3597                         get {
3598                                 return is_readonly;
3599                         }
3600                 }
3601
3602                 protected Expression DoResolveBase (EmitContext ec, Expression lvalue_right_side)
3603                 {
3604                         if (local_info == null) {
3605                                 local_info = Block.GetLocalInfo (Name);
3606
3607                                 // is out param
3608                                 if (lvalue_right_side == EmptyExpression.Null)
3609                                         local_info.Used = true;
3610
3611                                 is_readonly = local_info.ReadOnly;
3612                         }
3613
3614                         type = local_info.VariableType;
3615
3616                         VariableInfo variable_info = local_info.VariableInfo;
3617                         if (lvalue_right_side != null){
3618                                 if (is_readonly){
3619                                         Error (1604, "cannot assign to `" + Name + "' because it is readonly");
3620                                         return null;
3621                                 }
3622
3623                                 if (variable_info != null)
3624                                         variable_info.SetAssigned (ec);
3625                         }
3626
3627                         Expression e = Block.GetConstantExpression (Name);
3628                         if (e != null) {
3629                                 local_info.Used = true;
3630                                 eclass = ExprClass.Value;
3631                                 return e.Resolve (ec);
3632                         }
3633
3634                         if ((variable_info != null) && !variable_info.IsAssigned (ec, loc))
3635                                 return null;
3636
3637                         if (lvalue_right_side == null)
3638                                 local_info.Used = true;
3639
3640                         if (ec.CurrentAnonymousMethod != null){
3641                                 //
3642                                 // If we are referencing a variable from the external block
3643                                 // flag it for capturing
3644                                 //
3645                                 if (local_info.Block.Toplevel != ec.CurrentBlock.Toplevel){
3646                                         if (local_info.AddressTaken){
3647                                                 AnonymousMethod.Error_AddressOfCapturedVar (local_info.Name, loc);
3648                                                 return null;
3649                                         }
3650                                         ec.CaptureVariable (local_info);
3651                                 }
3652                         }
3653
3654                         return this;
3655                 }
3656
3657                 public override Expression DoResolve (EmitContext ec)
3658                 {
3659                         return DoResolveBase (ec, null);
3660                 }
3661
3662                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3663                 {
3664                         Expression ret = DoResolveBase (ec, right_side);
3665                         if (ret != null)
3666                                 CheckObsoleteAttribute (ret.Type);
3667
3668                         return ret;
3669                 }
3670
3671                 public bool VerifyFixed (bool is_expression)
3672                 {
3673                         return !is_expression || local_info.IsFixed;
3674                 }
3675
3676                 public override void Emit (EmitContext ec)
3677                 {
3678                         ILGenerator ig = ec.ig;
3679
3680                         if (local_info.FieldBuilder == null){
3681                                 //
3682                                 // A local variable on the local CLR stack
3683                                 //
3684                                 ig.Emit (OpCodes.Ldloc, local_info.LocalBuilder);
3685                         } else {
3686                                 //
3687                                 // A local variable captured by anonymous methods.
3688                                 //
3689                                 if (!prepared)
3690                                         ec.EmitCapturedVariableInstance (local_info);
3691
3692                                 ig.Emit (OpCodes.Ldfld, local_info.FieldBuilder);
3693                         }
3694                 }
3695
3696                 public void Emit (EmitContext ec, bool leave_copy)
3697                 {
3698                         Emit (ec);
3699                         if (leave_copy){
3700                                 ec.ig.Emit (OpCodes.Dup);
3701                                 if (local_info.FieldBuilder != null){
3702                                         temp = new LocalTemporary (ec, Type);
3703                                         temp.Store (ec);
3704                                 }
3705                         }
3706                 }
3707
3708                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3709                 {
3710                         ILGenerator ig = ec.ig;
3711                         prepared = prepare_for_load;
3712
3713                         if (local_info.FieldBuilder == null){
3714                                 //
3715                                 // A local variable on the local CLR stack
3716                                 //
3717                                 if (local_info.LocalBuilder == null)
3718                                         throw new Exception ("This should not happen: both Field and Local are null");
3719
3720                                 source.Emit (ec);
3721                                 if (leave_copy)
3722                                         ec.ig.Emit (OpCodes.Dup);
3723                                 ig.Emit (OpCodes.Stloc, local_info.LocalBuilder);
3724                         } else {
3725                                 //
3726                                 // A local variable captured by anonymous methods or itereators.
3727                                 //
3728                                 ec.EmitCapturedVariableInstance (local_info);
3729
3730                                 if (prepare_for_load)
3731                                         ig.Emit (OpCodes.Dup);
3732                                 source.Emit (ec);
3733                                 if (leave_copy){
3734                                         ig.Emit (OpCodes.Dup);
3735                                         temp = new LocalTemporary (ec, Type);
3736                                         temp.Store (ec);
3737                                 }
3738                                 ig.Emit (OpCodes.Stfld, local_info.FieldBuilder);
3739                                 if (temp != null)
3740                                         temp.Emit (ec);
3741                         }
3742                 }
3743
3744                 public void AddressOf (EmitContext ec, AddressOp mode)
3745                 {
3746                         ILGenerator ig = ec.ig;
3747
3748                         if (local_info.FieldBuilder == null){
3749                                 //
3750                                 // A local variable on the local CLR stack
3751                                 //
3752                                 ig.Emit (OpCodes.Ldloca, local_info.LocalBuilder);
3753                         } else {
3754                                 //
3755                                 // A local variable captured by anonymous methods or iterators
3756                                 //
3757                                 ec.EmitCapturedVariableInstance (local_info);
3758                                 ig.Emit (OpCodes.Ldflda, local_info.FieldBuilder);
3759                         }
3760                 }
3761
3762                 public override string ToString ()
3763                 {
3764                         return String.Format ("{0} ({1}:{2})", GetType (), Name, loc);
3765                 }
3766         }
3767
3768         /// <summary>
3769         ///   This represents a reference to a parameter in the intermediate
3770         ///   representation.
3771         /// </summary>
3772         public class ParameterReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
3773                 Parameters pars;
3774                 String name;
3775                 int idx;
3776                 Block block;
3777                 VariableInfo vi;
3778                 public Parameter.Modifier mod;
3779                 public bool is_ref, is_out, prepared;
3780
3781                 public bool IsOut {
3782                         get {
3783                                 return is_out;
3784                         }
3785                 }
3786
3787                 public bool IsRef {
3788                         get {
3789                                 return is_ref;
3790                         }
3791                 }
3792
3793                 LocalTemporary temp;
3794
3795                 public ParameterReference (Parameters pars, Block block, int idx, string name, Location loc)
3796                 {
3797                         this.pars = pars;
3798                         this.block = block;
3799                         this.idx  = idx;
3800                         this.name = name;
3801                         this.loc = loc;
3802                         eclass = ExprClass.Variable;
3803                 }
3804
3805                 public VariableInfo VariableInfo {
3806                         get { return vi; }
3807                 }
3808
3809                 public bool VerifyFixed (bool is_expression)
3810                 {
3811                         return !is_expression || TypeManager.IsValueType (type);
3812                 }
3813
3814                 public bool IsAssigned (EmitContext ec, Location loc)
3815                 {
3816                         if (!ec.DoFlowAnalysis || !is_out || ec.CurrentBranching.IsAssigned (vi))
3817                                 return true;
3818
3819                         Report.Error (165, loc,
3820                                       "Use of unassigned parameter `" + name + "'");
3821                         return false;
3822                 }
3823
3824                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
3825                 {
3826                         if (!ec.DoFlowAnalysis || !is_out || ec.CurrentBranching.IsFieldAssigned (vi, field_name))
3827                                 return true;
3828
3829                         Report.Error (170, loc,
3830                                       "Use of possibly unassigned field `" + field_name + "'");
3831                         return false;
3832                 }
3833
3834                 public void SetAssigned (EmitContext ec)
3835                 {
3836                         if (is_out && ec.DoFlowAnalysis)
3837                                 ec.CurrentBranching.SetAssigned (vi);
3838                 }
3839
3840                 public void SetFieldAssigned (EmitContext ec, string field_name)
3841                 {
3842                         if (is_out && ec.DoFlowAnalysis)
3843                                 ec.CurrentBranching.SetFieldAssigned (vi, field_name);
3844                 }
3845
3846                 protected void DoResolveBase (EmitContext ec)
3847                 {
3848                         type = pars.GetParameterInfo (ec, idx, out mod);
3849                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3850                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3851                         eclass = ExprClass.Variable;
3852
3853                         if (is_out)
3854                                 vi = block.ParameterMap [idx];
3855
3856                         if (ec.CurrentAnonymousMethod != null){
3857                                 if (is_ref){
3858                                         Report.Error (1628, Location,
3859                                                       "Can not reference a ref or out parameter in an anonymous method");
3860                                         return;
3861                                 }
3862
3863                                 //
3864                                 // If we are referencing the parameter from the external block
3865                                 // flag it for capturing
3866                                 //
3867                                 //Console.WriteLine ("Is parameter `{0}' local? {1}", name, block.IsLocalParameter (name));
3868                                 if (!block.IsLocalParameter (name)){
3869                                         ec.CaptureParameter (name, type, idx);
3870                                 }
3871                         }
3872                 }
3873
3874                 //
3875                 // Notice that for ref/out parameters, the type exposed is not the
3876                 // same type exposed externally.
3877                 //
3878                 // for "ref int a":
3879                 //   externally we expose "int&"
3880                 //   here we expose       "int".
3881                 //
3882                 // We record this in "is_ref".  This means that the type system can treat
3883                 // the type as it is expected, but when we generate the code, we generate
3884                 // the alternate kind of code.
3885                 //
3886                 public override Expression DoResolve (EmitContext ec)
3887                 {
3888                         DoResolveBase (ec);
3889
3890                         if (is_out && ec.DoFlowAnalysis && !IsAssigned (ec, loc))
3891                                 return null;
3892
3893                         if (ec.RemapToProxy)
3894                                 return ec.RemapParameter (idx);
3895
3896                         return this;
3897                 }
3898
3899                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3900                 {
3901                         DoResolveBase (ec);
3902
3903                         SetAssigned (ec);
3904
3905                         if (ec.RemapToProxy)
3906                                 return ec.RemapParameterLValue (idx, right_side);
3907
3908                         return this;
3909                 }
3910
3911                 static public void EmitLdArg (ILGenerator ig, int x)
3912                 {
3913                         if (x <= 255){
3914                                 switch (x){
3915                                 case 0: ig.Emit (OpCodes.Ldarg_0); break;
3916                                 case 1: ig.Emit (OpCodes.Ldarg_1); break;
3917                                 case 2: ig.Emit (OpCodes.Ldarg_2); break;
3918                                 case 3: ig.Emit (OpCodes.Ldarg_3); break;
3919                                 default: ig.Emit (OpCodes.Ldarg_S, (byte) x); break;
3920                                 }
3921                         } else
3922                                 ig.Emit (OpCodes.Ldarg, x);
3923                 }
3924
3925                 //
3926                 // This method is used by parameters that are references, that are
3927                 // being passed as references:  we only want to pass the pointer (that
3928                 // is already stored in the parameter, not the address of the pointer,
3929                 // and not the value of the variable).
3930                 //
3931                 public void EmitLoad (EmitContext ec)
3932                 {
3933                         ILGenerator ig = ec.ig;
3934                         int arg_idx = idx;
3935
3936                         if (!ec.IsStatic)
3937                                 arg_idx++;
3938
3939                         EmitLdArg (ig, arg_idx);
3940
3941                         //
3942                         // FIXME: Review for anonymous methods
3943                         //
3944                 }
3945
3946                 public override void Emit (EmitContext ec)
3947                 {
3948                         if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
3949                                 ec.EmitParameter (name);
3950                                 return;
3951                         }
3952
3953                         Emit (ec, false);
3954                 }
3955
3956                 public void Emit (EmitContext ec, bool leave_copy)
3957                 {
3958                         ILGenerator ig = ec.ig;
3959                         int arg_idx = idx;
3960
3961                         if (!ec.IsStatic)
3962                                 arg_idx++;
3963
3964                         EmitLdArg (ig, arg_idx);
3965
3966                         if (is_ref) {
3967                                 if (prepared)
3968                                         ec.ig.Emit (OpCodes.Dup);
3969
3970                                 //
3971                                 // If we are a reference, we loaded on the stack a pointer
3972                                 // Now lets load the real value
3973                                 //
3974                                 LoadFromPtr (ig, type);
3975                         }
3976
3977                         if (leave_copy) {
3978                                 ec.ig.Emit (OpCodes.Dup);
3979
3980                                 if (is_ref) {
3981                                         temp = new LocalTemporary (ec, type);
3982                                         temp.Store (ec);
3983                                 }
3984                         }
3985                 }
3986
3987                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3988                 {
3989                         if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
3990                                 ec.EmitAssignParameter (name, source, leave_copy, prepare_for_load);
3991                                 return;
3992                         }
3993
3994                         ILGenerator ig = ec.ig;
3995                         int arg_idx = idx;
3996
3997                         prepared = prepare_for_load;
3998
3999                         if (!ec.IsStatic)
4000                                 arg_idx++;
4001
4002                         if (is_ref && !prepared)
4003                                 EmitLdArg (ig, arg_idx);
4004
4005                         source.Emit (ec);
4006
4007                         if (leave_copy)
4008                                 ec.ig.Emit (OpCodes.Dup);
4009
4010                         if (is_ref) {
4011                                 if (leave_copy) {
4012                                         temp = new LocalTemporary (ec, type);
4013                                         temp.Store (ec);
4014                                 }
4015
4016                                 StoreFromPtr (ig, type);
4017
4018                                 if (temp != null)
4019                                         temp.Emit (ec);
4020                         } else {
4021                                 if (arg_idx <= 255)
4022                                         ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
4023                                 else
4024                                         ig.Emit (OpCodes.Starg, arg_idx);
4025                         }
4026                 }
4027
4028                 public void AddressOf (EmitContext ec, AddressOp mode)
4029                 {
4030                         if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
4031                                 ec.EmitAddressOfParameter (name);
4032                                 return;
4033                         }
4034
4035                         int arg_idx = idx;
4036
4037                         if (!ec.IsStatic)
4038                                 arg_idx++;
4039
4040                         if (is_ref){
4041                                 if (arg_idx <= 255)
4042                                         ec.ig.Emit (OpCodes.Ldarg_S, (byte) arg_idx);
4043                                 else
4044                                         ec.ig.Emit (OpCodes.Ldarg, arg_idx);
4045                         } else {
4046                                 if (arg_idx <= 255)
4047                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
4048                                 else
4049                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
4050                         }
4051                 }
4052
4053         }
4054
4055         /// <summary>
4056         ///   Used for arguments to New(), Invocation()
4057         /// </summary>
4058         public class Argument {
4059                 public enum AType : byte {
4060                         Expression,
4061                         Ref,
4062                         Out,
4063                         ArgList
4064                 };
4065
4066                 public readonly AType ArgType;
4067                 public Expression Expr;
4068
4069                 public Argument (Expression expr, AType type)
4070                 {
4071                         this.Expr = expr;
4072                         this.ArgType = type;
4073                 }
4074
4075                 public Argument (Expression expr)
4076                 {
4077                         this.Expr = expr;
4078                         this.ArgType = AType.Expression;
4079                 }
4080
4081                 public Type Type {
4082                         get {
4083                                 if (ArgType == AType.Ref || ArgType == AType.Out)
4084                                         return TypeManager.GetReferenceType (Expr.Type);
4085                                 else
4086                                         return Expr.Type;
4087                         }
4088                 }
4089
4090                 public Parameter.Modifier GetParameterModifier ()
4091                 {
4092                         switch (ArgType) {
4093                         case AType.Out:
4094                                 return Parameter.Modifier.OUT | Parameter.Modifier.ISBYREF;
4095
4096                         case AType.Ref:
4097                                 return Parameter.Modifier.REF | Parameter.Modifier.ISBYREF;
4098
4099                         default:
4100                                 return Parameter.Modifier.NONE;
4101                         }
4102                 }
4103
4104                 public static string FullDesc (Argument a)
4105                 {
4106                         if (a.ArgType == AType.ArgList)
4107                                 return "__arglist";
4108
4109                         return (a.ArgType == AType.Ref ? "ref " :
4110                                 (a.ArgType == AType.Out ? "out " : "")) +
4111                                 TypeManager.CSharpName (a.Expr.Type);
4112                 }
4113
4114                 public bool ResolveMethodGroup (EmitContext ec, Location loc)
4115                 {
4116                         // FIXME: csc doesn't report any error if you try to use `ref' or
4117                         //        `out' in a delegate creation expression.
4118                         Expr = Expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
4119                         if (Expr == null)
4120                                 return false;
4121
4122                         return true;
4123                 }
4124
4125                 public bool Resolve (EmitContext ec, Location loc)
4126                 {
4127                         if (ArgType == AType.Ref) {
4128                                 Expr = Expr.Resolve (ec);
4129                                 if (Expr == null)
4130                                         return false;
4131
4132                                 if (!ec.IsConstructor) {
4133                                         FieldExpr fe = Expr as FieldExpr;
4134                                         if (fe != null && fe.FieldInfo.IsInitOnly) {
4135                                                 if (fe.FieldInfo.IsStatic)
4136                                                         Report.Error (199, loc, "A static readonly field cannot be passed ref or out (except in a static constructor)");
4137                                                 else
4138                                                         Report.Error (192, loc, "A readonly field cannot be passed ref or out (except in a constructor)");
4139                                                 return false;
4140                                         }
4141                                 }
4142                                 Expr = Expr.ResolveLValue (ec, Expr);
4143                         } else if (ArgType == AType.Out)
4144                                 Expr = Expr.ResolveLValue (ec, EmptyExpression.Null);
4145                         else
4146                                 Expr = Expr.Resolve (ec);
4147
4148                         if (Expr == null)
4149                                 return false;
4150
4151                         if (ArgType == AType.Expression)
4152                                 return true;
4153                         else {
4154                                 //
4155                                 // Catch errors where fields of a MarshalByRefObject are passed as ref or out
4156                                 // This is only allowed for `this'
4157                                 //
4158                                 FieldExpr fe = Expr as FieldExpr;
4159                                 if (fe != null && !fe.IsStatic){
4160                                         Expression instance = fe.InstanceExpression;
4161
4162                                         if (instance.GetType () != typeof (This)){
4163                                                 if (fe.InstanceExpression.Type.IsSubclassOf (TypeManager.mbr_type)){
4164                                                         Report.SymbolRelatedToPreviousError (fe.InstanceExpression.Type);
4165                                                         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",
4166                                                                 fe.Name);
4167                                                         return false;
4168                                                 }
4169                                         }
4170                                 }
4171                         }
4172
4173                         if (Expr.eclass != ExprClass.Variable){
4174                                 //
4175                                 // We just probe to match the CSC output
4176                                 //
4177                                 if (Expr.eclass == ExprClass.PropertyAccess ||
4178                                     Expr.eclass == ExprClass.IndexerAccess){
4179                                         Report.Error (
4180                                                 206, loc,
4181                                                 "A property or indexer can not be passed as an out or ref " +
4182                                                 "parameter");
4183                                 } else {
4184                                         Report.Error (
4185                                                 1510, loc,
4186                                                 "An lvalue is required as an argument to out or ref");
4187                                 }
4188                                 return false;
4189                         }
4190
4191                         return true;
4192                 }
4193
4194                 public void Emit (EmitContext ec)
4195                 {
4196                         //
4197                         // Ref and Out parameters need to have their addresses taken.
4198                         //
4199                         // ParameterReferences might already be references, so we want
4200                         // to pass just the value
4201                         //
4202                         if (ArgType == AType.Ref || ArgType == AType.Out){
4203                                 AddressOp mode = AddressOp.Store;
4204
4205                                 if (ArgType == AType.Ref)
4206                                         mode |= AddressOp.Load;
4207
4208                                 if (Expr is ParameterReference){
4209                                         ParameterReference pr = (ParameterReference) Expr;
4210
4211                                         if (pr.IsRef)
4212                                                 pr.EmitLoad (ec);
4213                                         else {
4214
4215                                                 pr.AddressOf (ec, mode);
4216                                         }
4217                                 } else {
4218                                         ((IMemoryLocation)Expr).AddressOf (ec, mode);
4219                                 }
4220                         } else
4221                                 Expr.Emit (ec);
4222                 }
4223         }
4224
4225         /// <summary>
4226         ///   Invocation of methods or delegates.
4227         /// </summary>
4228         public class Invocation : ExpressionStatement {
4229                 public readonly ArrayList Arguments;
4230
4231                 Expression expr;
4232                 MethodBase method = null;
4233
4234                 static Hashtable method_parameter_cache;
4235
4236                 static Invocation ()
4237                 {
4238                         method_parameter_cache = new PtrHashtable ();
4239                 }
4240
4241                 //
4242                 // arguments is an ArrayList, but we do not want to typecast,
4243                 // as it might be null.
4244                 //
4245                 // FIXME: only allow expr to be a method invocation or a
4246                 // delegate invocation (7.5.5)
4247                 //
4248                 public Invocation (Expression expr, ArrayList arguments, Location l)
4249                 {
4250                         this.expr = expr;
4251                         Arguments = arguments;
4252                         loc = l;
4253                 }
4254
4255                 public Expression Expr {
4256                         get {
4257                                 return expr;
4258                         }
4259                 }
4260
4261                 /// <summary>
4262                 ///   Returns the Parameters (a ParameterData interface) for the
4263                 ///   Method `mb'
4264                 /// </summary>
4265                 public static ParameterData GetParameterData (MethodBase mb)
4266                 {
4267                         object pd = method_parameter_cache [mb];
4268                         object ip;
4269
4270                         if (pd != null)
4271                                 return (ParameterData) pd;
4272
4273
4274                         ip = TypeManager.LookupParametersByBuilder (mb);
4275                         if (ip != null){
4276                                 method_parameter_cache [mb] = ip;
4277
4278                                 return (ParameterData) ip;
4279                         } else {
4280                                 ReflectionParameters rp = new ReflectionParameters (mb);
4281                                 method_parameter_cache [mb] = rp;
4282
4283                                 return (ParameterData) rp;
4284                         }
4285                 }
4286
4287                 /// <summary>
4288                 ///   Determines "better conversion" as specified in 7.4.2.3
4289                 ///
4290                 ///    Returns : p    if a->p is better,
4291                 ///              q    if a->q is better,
4292                 ///              null if neither is better
4293                 /// </summary>
4294                 static Type BetterConversion (EmitContext ec, Argument a, Type p, Type q, Location loc)
4295                 {
4296                         Type argument_type = a.Type;
4297                         Expression argument_expr = a.Expr;
4298
4299                         if (argument_type == null)
4300                                 throw new Exception ("Expression of type " + a.Expr +
4301                                                      " does not resolve its type");
4302
4303                         if (p == null || q == null)
4304                                 throw new InternalErrorException ("BetterConversion Got a null conversion");
4305
4306                         if (p == q)
4307                                 return null;
4308
4309                         if (argument_expr is NullLiteral) {
4310                                 //
4311                                 // If the argument is null and one of the types to compare is 'object' and
4312                                 // the other is a reference type, we prefer the other.
4313                                 //
4314                                 // This follows from the usual rules:
4315                                 //   * There is an implicit conversion from 'null' to type 'object'
4316                                 //   * There is an implicit conversion from 'null' to any reference type
4317                                 //   * There is an implicit conversion from any reference type to type 'object'
4318                                 //   * There is no implicit conversion from type 'object' to other reference types
4319                                 //  => Conversion of 'null' to a reference type is better than conversion to 'object'
4320                                 //
4321                                 //  FIXME: This probably isn't necessary, since the type of a NullLiteral is the
4322                                 //         null type. I think it used to be 'object' and thus needed a special
4323                                 //         case to avoid the immediately following two checks.
4324                                 //
4325                                 if (!p.IsValueType && q == TypeManager.object_type)
4326                                         return p;
4327                                 if (!q.IsValueType && p == TypeManager.object_type)
4328                                         return q;
4329                         }
4330
4331                         if (argument_type == p)
4332                                 return p;
4333
4334                         if (argument_type == q)
4335                                 return q;
4336
4337                         Expression p_tmp = new EmptyExpression (p);
4338                         Expression q_tmp = new EmptyExpression (q);
4339
4340                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
4341                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
4342
4343                         if (p_to_q && !q_to_p)
4344                                 return p;
4345
4346                         if (q_to_p && !p_to_q)
4347                                 return q;
4348
4349                         if (p == TypeManager.sbyte_type)
4350                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
4351                                     q == TypeManager.uint32_type || q == TypeManager.uint64_type)
4352                                         return p;
4353                         if (q == TypeManager.sbyte_type)
4354                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
4355                                     p == TypeManager.uint32_type || p == TypeManager.uint64_type)
4356                                         return q;
4357
4358                         if (p == TypeManager.short_type)
4359                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
4360                                     q == TypeManager.uint64_type)
4361                                         return p;
4362                         if (q == TypeManager.short_type)
4363                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
4364                                     p == TypeManager.uint64_type)
4365                                         return q;
4366
4367                         if (p == TypeManager.int32_type)
4368                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
4369                                         return p;
4370                         if (q == TypeManager.int32_type)
4371                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
4372                                         return q;
4373
4374                         if (p == TypeManager.int64_type)
4375                                 if (q == TypeManager.uint64_type)
4376                                         return p;
4377                         if (q == TypeManager.int64_type)
4378                                 if (p == TypeManager.uint64_type)
4379                                         return q;
4380
4381                         return null;
4382                 }
4383
4384                 /// <summary>
4385                 ///   Determines "Better function" between candidate
4386                 ///   and the current best match
4387                 /// </summary>
4388                 /// <remarks>
4389                 ///    Returns an integer indicating :
4390                 ///     false if candidate ain't better
4391                 ///     true if candidate is better than the current best match
4392                 /// </remarks>
4393                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
4394                                             MethodBase candidate, bool candidate_params,
4395                                             MethodBase best, bool best_params, Location loc)
4396                 {
4397                         ParameterData candidate_pd = GetParameterData (candidate);
4398                         ParameterData best_pd = GetParameterData (best);
4399
4400                         int cand_count = candidate_pd.Count;
4401
4402                         //
4403                         // If there is no best method, than this one
4404                         // is better, however, if we already found a
4405                         // best method, we cant tell. This happens
4406                         // if we have:
4407                         //
4408                         //      interface IFoo {
4409                         //              void DoIt ();
4410                         //      }
4411                         //
4412                         //      interface IBar {
4413                         //              void DoIt ();
4414                         //      }
4415                         //
4416                         //      interface IFooBar : IFoo, IBar {}
4417                         //
4418                         // We cant tell if IFoo.DoIt is better than IBar.DoIt
4419                         //
4420                         // However, we have to consider that
4421                         // Trim (); is better than Trim (params char[] chars);
4422                         //
4423                         if (cand_count == 0 && argument_count == 0)
4424                                 return !candidate_params && best_params;
4425
4426                         if ((candidate_pd.ParameterModifier (cand_count - 1) != Parameter.Modifier.PARAMS) &&
4427                             (candidate_pd.ParameterModifier (cand_count - 1) != Parameter.Modifier.ARGLIST))
4428                                 if (cand_count != argument_count)
4429                                         return false;
4430
4431                         bool better_at_least_one = false;
4432                         for (int j = 0; j < argument_count; ++j) {
4433                                 Argument a = (Argument) args [j];
4434
4435                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (j));
4436                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (j));
4437
4438                                 if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
4439                                         if (candidate_params)
4440                                                 ct = TypeManager.GetElementType (ct);
4441
4442                                 if (best_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
4443                                         if (best_params)
4444                                                 bt = TypeManager.GetElementType (bt);
4445
4446                                 Type better = BetterConversion (ec, a, ct, bt, loc);
4447
4448                                 // for each argument, the conversion to 'ct' should be no worse than
4449                                 // the conversion to 'bt'.
4450                                 if (better == bt)
4451                                         return false;
4452
4453                                 // for at least one argument, the conversion to 'ct' should be better than
4454                                 // the conversion to 'bt'.
4455                                 if (better == ct)
4456                                         better_at_least_one = true;
4457                         }
4458
4459                         //
4460                         // If a method (in the normal form) with the
4461                         // same signature as the expanded form of the
4462                         // current best params method already exists,
4463                         // the expanded form is not applicable so we
4464                         // force it to select the candidate
4465                         //
4466                         if (!candidate_params && best_params && cand_count == argument_count)
4467                                 return true;
4468
4469                         return better_at_least_one;
4470                 }
4471
4472                 public static string FullMethodDesc (MethodBase mb)
4473                 {
4474                         string ret_type = "";
4475
4476                         if (mb == null)
4477                                 return "";
4478
4479                         if (mb is MethodInfo)
4480                                 ret_type = TypeManager.CSharpName (((MethodInfo) mb).ReturnType);
4481
4482                         StringBuilder sb = new StringBuilder (ret_type);
4483                         sb.Append (" ");
4484                         sb.Append (mb.ReflectedType.ToString ());
4485                         sb.Append (".");
4486                         sb.Append (mb.Name);
4487
4488                         ParameterData pd = GetParameterData (mb);
4489
4490                         int count = pd.Count;
4491                         sb.Append (" (");
4492
4493                         for (int i = count; i > 0; ) {
4494                                 i--;
4495
4496                                 sb.Append (pd.ParameterDesc (count - i - 1));
4497                                 if (i != 0)
4498                                         sb.Append (", ");
4499                         }
4500
4501                         sb.Append (")");
4502                         return sb.ToString ();
4503                 }
4504
4505                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
4506                 {
4507                         MemberInfo [] miset;
4508                         MethodGroupExpr union;
4509
4510                         if (mg1 == null) {
4511                                 if (mg2 == null)
4512                                         return null;
4513                                 return (MethodGroupExpr) mg2;
4514                         } else {
4515                                 if (mg2 == null)
4516                                         return (MethodGroupExpr) mg1;
4517                         }
4518
4519                         MethodGroupExpr left_set = null, right_set = null;
4520                         int length1 = 0, length2 = 0;
4521
4522                         left_set = (MethodGroupExpr) mg1;
4523                         length1 = left_set.Methods.Length;
4524
4525                         right_set = (MethodGroupExpr) mg2;
4526                         length2 = right_set.Methods.Length;
4527
4528                         ArrayList common = new ArrayList ();
4529
4530                         foreach (MethodBase r in right_set.Methods){
4531                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
4532                                         common.Add (r);
4533                         }
4534
4535                         miset = new MemberInfo [length1 + length2 - common.Count];
4536                         left_set.Methods.CopyTo (miset, 0);
4537
4538                         int k = length1;
4539
4540                         foreach (MethodBase r in right_set.Methods) {
4541                                 if (!common.Contains (r))
4542                                         miset [k++] = r;
4543                         }
4544
4545                         union = new MethodGroupExpr (miset, loc);
4546
4547                         return union;
4548                 }
4549
4550                 static bool IsParamsMethodApplicable (EmitContext ec, MethodGroupExpr me,
4551                                                       ArrayList arguments, int arg_count,
4552                                                       ref MethodBase candidate)
4553                 {
4554                         return IsParamsMethodApplicable (
4555                                 ec, me, arguments, arg_count, false, ref candidate) ||
4556                                 IsParamsMethodApplicable (
4557                                         ec, me, arguments, arg_count, true, ref candidate);
4558
4559
4560                 }
4561
4562                 static bool IsParamsMethodApplicable (EmitContext ec, MethodGroupExpr me,
4563                                                       ArrayList arguments, int arg_count,
4564                                                       bool do_varargs, ref MethodBase candidate)
4565                 {
4566                         return IsParamsMethodApplicable (
4567                                 ec, arguments, arg_count, candidate, do_varargs);
4568                 }
4569
4570                 /// <summary>
4571                 ///   Determines if the candidate method, if a params method, is applicable
4572                 ///   in its expanded form to the given set of arguments
4573                 /// </summary>
4574                 static bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments,
4575                                                       int arg_count, MethodBase candidate,
4576                                                       bool do_varargs)
4577                 {
4578                         ParameterData pd = GetParameterData (candidate);
4579
4580                         int pd_count = pd.Count;
4581                         if (pd_count == 0)
4582                                 return false;
4583
4584                         int count = pd_count - 1;
4585                         if (do_varargs) {
4586                                 if (pd.ParameterModifier (count) != Parameter.Modifier.ARGLIST)
4587                                         return false;
4588                                 if (pd_count != arg_count)
4589                                         return false;
4590                         } else {
4591                                 if (pd.ParameterModifier (count) != Parameter.Modifier.PARAMS)
4592                                         return false;
4593                         }
4594
4595                         if (count > arg_count)
4596                                 return false;
4597
4598                         if (pd_count == 1 && arg_count == 0)
4599                                 return true;
4600
4601                         //
4602                         // If we have come this far, the case which
4603                         // remains is when the number of parameters is
4604                         // less than or equal to the argument count.
4605                         //
4606                         for (int i = 0; i < count; ++i) {
4607
4608                                 Argument a = (Argument) arguments [i];
4609
4610                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
4611                                         (unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF)));
4612                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
4613                                         (unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF)));
4614
4615                                 if (a_mod == p_mod) {
4616
4617                                         if (a_mod == Parameter.Modifier.NONE)
4618                                                 if (!Convert.ImplicitConversionExists (ec,
4619                                                                                        a.Expr,
4620                                                                                        pd.ParameterType (i)))
4621                                                         return false;
4622
4623                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
4624                                                 Type pt = pd.ParameterType (i);
4625
4626                                                 if (!pt.IsByRef)
4627                                                         pt = TypeManager.GetReferenceType (pt);
4628
4629                                                 if (pt != a.Type)
4630                                                         return false;
4631                                         }
4632                                 } else
4633                                         return false;
4634
4635                         }
4636
4637                         if (do_varargs) {
4638                                 Argument a = (Argument) arguments [count];
4639                                 if (!(a.Expr is Arglist))
4640                                         return false;
4641
4642                                 return true;
4643                         }
4644
4645                         Type element_type = TypeManager.GetElementType (pd.ParameterType (pd_count - 1));
4646
4647                         for (int i = pd_count - 1; i < arg_count; i++) {
4648                                 Argument a = (Argument) arguments [i];
4649
4650                                 if (!Convert.ImplicitConversionExists (ec, a.Expr, element_type))
4651                                         return false;
4652                         }
4653
4654                         return true;
4655                 }
4656
4657                 static bool IsApplicable (EmitContext ec, MethodGroupExpr me,
4658                                           ArrayList arguments, int arg_count,
4659                                           ref MethodBase candidate)
4660                 {
4661                         return IsApplicable (ec, arguments, arg_count, candidate);
4662                 }
4663
4664                 /// <summary>
4665                 ///   Determines if the candidate method is applicable (section 14.4.2.1)
4666                 ///   to the given set of arguments
4667                 /// </summary>
4668                 static bool IsApplicable (EmitContext ec, ArrayList arguments, int arg_count,
4669                                           MethodBase candidate)
4670                 {
4671                         ParameterData pd = GetParameterData (candidate);
4672
4673                         if (arg_count != pd.Count)
4674                                 return false;
4675
4676                         for (int i = arg_count; i > 0; ) {
4677                                 i--;
4678
4679                                 Argument a = (Argument) arguments [i];
4680
4681                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
4682                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
4683                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
4684                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
4685
4686
4687                                 if (a_mod == p_mod ||
4688                                     (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
4689                                         if (a_mod == Parameter.Modifier.NONE) {
4690                                                 if (!Convert.ImplicitConversionExists (ec,
4691                                                                                        a.Expr,
4692                                                                                        pd.ParameterType (i)))
4693                                                         return false;
4694                                         }
4695
4696                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
4697                                                 Type pt = pd.ParameterType (i);
4698
4699                                                 if (!pt.IsByRef)
4700                                                         pt = TypeManager.GetReferenceType (pt);
4701
4702                                                 if (pt != a.Type)
4703                                                         return false;
4704                                         }
4705                                 } else
4706                                         return false;
4707                         }
4708
4709                         return true;
4710                 }
4711
4712                 static private bool IsAncestralType (Type first_type, Type second_type)
4713                 {
4714                         return first_type != second_type &&
4715                                 (second_type.IsSubclassOf (first_type) ||
4716                                  TypeManager.ImplementsInterface (second_type, first_type));
4717                 }
4718
4719                 /// <summary>
4720                 ///   Find the Applicable Function Members (7.4.2.1)
4721                 ///
4722                 ///   me: Method Group expression with the members to select.
4723                 ///       it might contain constructors or methods (or anything
4724                 ///       that maps to a method).
4725                 ///
4726                 ///   Arguments: ArrayList containing resolved Argument objects.
4727                 ///
4728                 ///   loc: The location if we want an error to be reported, or a Null
4729                 ///        location for "probing" purposes.
4730                 ///
4731                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4732                 ///            that is the best match of me on Arguments.
4733                 ///
4734                 /// </summary>
4735                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
4736                                                           ArrayList Arguments, bool may_fail,
4737                                                           Location loc)
4738                 {
4739                         MethodBase method = null;
4740                         bool method_params = false;
4741                         Type applicable_type = null;
4742                         int arg_count = 0;
4743                         ArrayList candidates = new ArrayList ();
4744
4745                         //
4746                         // Used to keep a map between the candidate
4747                         // and whether it is being considered in its
4748                         // normal or expanded form
4749                         //
4750                         // false is normal form, true is expanded form
4751                         //
4752                         Hashtable candidate_to_form = null;
4753
4754                         if (Arguments != null)
4755                                 arg_count = Arguments.Count;
4756
4757                         if ((me.Name == "Invoke") &&
4758                             TypeManager.IsDelegateType (me.DeclaringType)) {
4759                                 Error_InvokeOnDelegate (loc);
4760                                 return null;
4761                         }
4762
4763                         MethodBase[] methods = me.Methods;
4764
4765                         //
4766                         // First we construct the set of applicable methods
4767                         //
4768                         bool is_sorted = true;
4769                         for (int i = 0; i < methods.Length; i++){
4770                                 Type decl_type = methods [i].DeclaringType;
4771
4772                                 //
4773                                 // If we have already found an applicable method
4774                                 // we eliminate all base types (Section 14.5.5.1)
4775                                 //
4776                                 if ((applicable_type != null) &&
4777                                     IsAncestralType (decl_type, applicable_type))
4778                                         continue;
4779
4780                                 //
4781                                 // Check if candidate is applicable (section 14.4.2.1)
4782                                 //   Is candidate applicable in normal form?
4783                                 //
4784                                 bool is_applicable = IsApplicable (
4785                                         ec, me, Arguments, arg_count, ref methods [i]);
4786
4787                                 if (!is_applicable &&
4788                                     (IsParamsMethodApplicable (
4789                                             ec, me, Arguments, arg_count, ref methods [i]))) {
4790                                         MethodBase candidate = methods [i];
4791                                         if (candidate_to_form == null)
4792                                                 candidate_to_form = new PtrHashtable ();
4793                                         candidate_to_form [candidate] = candidate;
4794                                         // Candidate is applicable in expanded form
4795                                         is_applicable = true;
4796                                 }
4797
4798                                 if (!is_applicable)
4799                                         continue;
4800
4801                                 candidates.Add (methods [i]);
4802
4803                                 if (applicable_type == null)
4804                                         applicable_type = decl_type;
4805                                 else if (applicable_type != decl_type) {
4806                                         is_sorted = false;
4807                                         if (IsAncestralType (applicable_type, decl_type))
4808                                                 applicable_type = decl_type;
4809                                 }
4810                         }
4811
4812                         int candidate_top = candidates.Count;
4813
4814                         if (candidate_top == 0) {
4815                                 //
4816                                 // Okay so we have failed to find anything so we
4817                                 // return by providing info about the closest match
4818                                 //
4819                                 for (int i = 0; i < methods.Length; ++i) {
4820                                         MethodBase c = (MethodBase) methods [i];
4821                                         ParameterData pd = GetParameterData (c);
4822
4823                                         if (pd.Count != arg_count)
4824                                                 continue;
4825
4826                                         VerifyArgumentsCompat (ec, Arguments, arg_count,
4827                                                                c, false, null, may_fail, loc);
4828                                         break;
4829                                 }
4830
4831                                 if (!may_fail) {
4832                                         string report_name = me.Name;
4833                                         if (report_name == ".ctor")
4834                                                 report_name = me.DeclaringType.ToString ();
4835
4836                                         Error_WrongNumArguments (
4837                                                 loc, report_name, arg_count);
4838                                         return null;
4839                                 }
4840
4841                                 return null;
4842                         }
4843
4844                         if (!is_sorted) {
4845                                 //
4846                                 // At this point, applicable_type is _one_ of the most derived types
4847                                 // in the set of types containing the methods in this MethodGroup.
4848                                 // Filter the candidates so that they only contain methods from the
4849                                 // most derived types.
4850                                 //
4851
4852                                 int finalized = 0; // Number of finalized candidates
4853
4854                                 do {
4855                                         // Invariant: applicable_type is a most derived type
4856
4857                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4858                                         // eliminating all it's base types.  At the same time, we'll also move
4859                                         // every unrelated type to the end of the array, and pick the next
4860                                         // 'applicable_type'.
4861
4862                                         Type next_applicable_type = null;
4863                                         int j = finalized; // where to put the next finalized candidate
4864                                         int k = finalized; // where to put the next undiscarded candidate
4865                                         for (int i = finalized; i < candidate_top; ++i) {
4866                                                 Type decl_type = ((MethodBase) candidates[i]).DeclaringType;
4867
4868                                                 if (decl_type == applicable_type) {
4869                                                         candidates[k++] = candidates[j];
4870                                                         candidates[j++] = candidates[i];
4871                                                         continue;
4872                                                 }
4873
4874                                                 if (IsAncestralType (decl_type, applicable_type))
4875                                                         continue;
4876
4877                                                 if (next_applicable_type != null &&
4878                                                     IsAncestralType (decl_type, next_applicable_type))
4879                                                         continue;
4880
4881                                                 candidates[k++] = candidates[i];
4882
4883                                                 if (next_applicable_type == null ||
4884                                                     IsAncestralType (next_applicable_type, decl_type))
4885                                                         next_applicable_type = decl_type;
4886                                         }
4887
4888                                         applicable_type = next_applicable_type;
4889                                         finalized = j;
4890                                         candidate_top = k;
4891                                 } while (applicable_type != null);
4892                         }
4893
4894                         //
4895                         // Now we actually find the best method
4896                         //
4897
4898                         method = (MethodBase) candidates[0];
4899                         method_params = candidate_to_form != null && candidate_to_form.Contains (method);
4900                         for (int ix = 1; ix < candidate_top; ix++){
4901                                 MethodBase candidate = (MethodBase) candidates [ix];
4902                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4903
4904                                 if (BetterFunction (ec, Arguments, arg_count,
4905                                                     candidate, cand_params,
4906                                                     method, method_params, loc)) {
4907                                         method = candidate;
4908                                         method_params = cand_params;
4909                                 }
4910                         }
4911
4912                         //
4913                         // Now check that there are no ambiguities i.e the selected method
4914                         // should be better than all the others
4915                         //
4916                         bool ambiguous = false;
4917                         for (int ix = 0; ix < candidate_top; ix++){
4918                                 MethodBase candidate = (MethodBase) candidates [ix];
4919
4920                                 if (candidate == method)
4921                                         continue;
4922
4923                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4924                                 if (!BetterFunction (ec, Arguments, arg_count,
4925                                                      method, method_params,
4926                                                      candidate, cand_params,
4927                                                      loc)) {
4928                                         Report.SymbolRelatedToPreviousError (candidate);
4929                                         ambiguous = true;
4930                                 }
4931                         }
4932
4933                         if (ambiguous) {
4934                                 Report.SymbolRelatedToPreviousError (method);
4935                                 Report.Error (121, loc, "Ambiguous call when selecting function due to implicit casts");
4936                                 return null;
4937                         }
4938
4939
4940                         //
4941                         // And now check if the arguments are all
4942                         // compatible, perform conversions if
4943                         // necessary etc. and return if everything is
4944                         // all right
4945                         //
4946                         if (!VerifyArgumentsCompat (ec, Arguments, arg_count, method,
4947                                                     method_params, null, may_fail, loc))
4948                                 return null;
4949
4950                         return method;
4951                 }
4952
4953                 static void Error_WrongNumArguments (Location loc, String name, int arg_count)
4954                 {
4955                         Report.Error (1501, loc,
4956                                       "No overload for method `" + name + "' takes `" +
4957                                       arg_count + "' arguments");
4958                 }
4959
4960                 static void Error_InvokeOnDelegate (Location loc)
4961                 {
4962                         Report.Error (1533, loc,
4963                                       "Invoke cannot be called directly on a delegate");
4964                 }
4965
4966                 static void Error_InvalidArguments (Location loc, int idx, MethodBase method,
4967                                                     Type delegate_type, string arg_sig, string par_desc)
4968                 {
4969                         if (delegate_type == null)
4970                                 Report.Error (1502, loc,
4971                                               "The best overloaded match for method '" +
4972                                               FullMethodDesc (method) +
4973                                               "' has some invalid arguments");
4974                         else
4975                                 Report.Error (1594, loc,
4976                                               "Delegate '" + delegate_type.ToString () +
4977                                               "' has some invalid arguments.");
4978                         Report.Error (1503, loc,
4979                                       String.Format ("Argument {0}: Cannot convert from '{1}' to '{2}'",
4980                                                      idx, arg_sig, par_desc));
4981                 }
4982
4983                 public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
4984                                                           int arg_count, MethodBase method,
4985                                                           bool chose_params_expanded,
4986                                                           Type delegate_type, bool may_fail,
4987                                                           Location loc)
4988                 {
4989                         ParameterData pd = GetParameterData (method);
4990                         int pd_count = pd.Count;
4991
4992                         for (int j = 0; j < arg_count; j++) {
4993                                 Argument a = (Argument) Arguments [j];
4994                                 Expression a_expr = a.Expr;
4995                                 Type parameter_type = pd.ParameterType (j);
4996                                 Parameter.Modifier pm = pd.ParameterModifier (j);
4997
4998                                 if (pm == Parameter.Modifier.PARAMS){
4999                                         if ((pm & ~Parameter.Modifier.PARAMS) != a.GetParameterModifier ()) {
5000                                                 if (!may_fail)
5001                                                         Error_InvalidArguments (
5002                                                                 loc, j, method, delegate_type,
5003                                                                 Argument.FullDesc (a), pd.ParameterDesc (j));
5004                                                 return false;
5005                                         }
5006
5007                                         if (chose_params_expanded)
5008                                                 parameter_type = TypeManager.GetElementType (parameter_type);
5009                                 } else if (pm == Parameter.Modifier.ARGLIST){
5010                                         continue;
5011                                 } else {
5012                                         //
5013                                         // Check modifiers
5014                                         //
5015                                         if (pd.ParameterModifier (j) != a.GetParameterModifier ()){
5016                                                 if (!may_fail)
5017                                                         Error_InvalidArguments (
5018                                                                 loc, j, method, delegate_type,
5019                                                                 Argument.FullDesc (a), pd.ParameterDesc (j));
5020                                                 return false;
5021                                         }
5022                                 }
5023
5024                                 //
5025                                 // Check Type
5026                                 //
5027                                 if (!a.Type.Equals (parameter_type)){
5028                                         Expression conv;
5029
5030                                         conv = Convert.ImplicitConversion (ec, a_expr, parameter_type, loc);
5031
5032                                         if (conv == null) {
5033                                                 if (!may_fail)
5034                                                         Error_InvalidArguments (
5035                                                                 loc, j, method, delegate_type,
5036                                                                 Argument.FullDesc (a), pd.ParameterDesc (j));
5037                                                 return false;
5038                                         }
5039
5040                                         //
5041                                         // Update the argument with the implicit conversion
5042                                         //
5043                                         if (a_expr != conv)
5044                                                 a.Expr = conv;
5045                                 }
5046
5047                                 if (parameter_type.IsPointer){
5048                                         if (!ec.InUnsafe){
5049                                                 UnsafeError (loc);
5050                                                 return false;
5051                                         }
5052                                 }
5053
5054                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
5055                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
5056                                 Parameter.Modifier p_mod = pd.ParameterModifier (j) &
5057                                         unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
5058
5059                                 if (a_mod != p_mod &&
5060                                     pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
5061                                         if (!may_fail) {
5062                                                 Report.Error (1502, loc,
5063                                                        "The best overloaded match for method '" + FullMethodDesc (method)+
5064                                                        "' has some invalid arguments");
5065                                                 Report.Error (1503, loc,
5066                                                        "Argument " + (j+1) +
5067                                                        ": Cannot convert from '" + Argument.FullDesc (a)
5068                                                        + "' to '" + pd.ParameterDesc (j) + "'");
5069                                         }
5070
5071                                         return false;
5072                                 }
5073                         }
5074
5075                         return true;
5076                 }
5077
5078                 public override Expression DoResolve (EmitContext ec)
5079                 {
5080                         //
5081                         // First, resolve the expression that is used to
5082                         // trigger the invocation
5083                         //
5084                         expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
5085                         if (expr == null)
5086                                 return null;
5087
5088                         if (!(expr is MethodGroupExpr)) {
5089                                 Type expr_type = expr.Type;
5090
5091                                 if (expr_type != null){
5092                                         bool IsDelegate = TypeManager.IsDelegateType (expr_type);
5093                                         if (IsDelegate)
5094                                                 return (new DelegateInvocation (
5095                                                         this.expr, Arguments, loc)).Resolve (ec);
5096                                 }
5097                         }
5098
5099                         if (!(expr is MethodGroupExpr)){
5100                                 expr.Error_UnexpectedKind (ResolveFlags.MethodGroup, loc);
5101                                 return null;
5102                         }
5103
5104                         //
5105                         // Next, evaluate all the expressions in the argument list
5106                         //
5107                         if (Arguments != null){
5108                                 foreach (Argument a in Arguments){
5109                                         if (!a.Resolve (ec, loc))
5110                                                 return null;
5111                                 }
5112                         }
5113
5114                         MethodGroupExpr mg = (MethodGroupExpr) expr;
5115                         method = OverloadResolve (ec, mg, Arguments, false, loc);
5116
5117                         if (method == null)
5118                                 return null;
5119
5120                         MethodInfo mi = method as MethodInfo;
5121                         if (mi != null) {
5122                                 type = TypeManager.TypeToCoreType (mi.ReturnType);
5123                                 if (!mi.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null)) {
5124                                         SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
5125                                         return null;
5126                                 }
5127
5128                                 Expression iexpr = mg.InstanceExpression;
5129                                 if (mi.IsStatic && (iexpr != null) && !(iexpr is This)) {
5130                                         if (mg.IdenticalTypeName)
5131                                                 mg.InstanceExpression = null;
5132                                         else {
5133                                                 MemberAccess.error176 (loc, mi.Name);
5134                                                 return null;
5135                                         }
5136                                 }
5137                         }
5138
5139                         if (type.IsPointer){
5140                                 if (!ec.InUnsafe){
5141                                         UnsafeError (loc);
5142                                         return null;
5143                                 }
5144                         }
5145
5146                         //
5147                         // Only base will allow this invocation to happen.
5148                         //
5149                         if (mg.IsBase && method.IsAbstract){
5150                                 Report.Error (205, loc, "Cannot call an abstract base member: " +
5151                                               FullMethodDesc (method));
5152                                 return null;
5153                         }
5154
5155                         if (method.Name == "Finalize" && Arguments == null) {
5156                                 if (mg.IsBase)
5157                                         Report.Error (250, loc, "Do not directly call your base class Finalize method. It is called automatically from your destructor");
5158                                 else
5159                                         Report.Error (245, loc, "Destructors and object.Finalize cannot be called directly. Consider calling IDisposable.Dispose if available");
5160                                 return null;
5161                         }
5162
5163                         if ((method.Attributes & MethodAttributes.SpecialName) != 0) {
5164                                 if (TypeManager.LookupDeclSpace (method.DeclaringType) != null || TypeManager.IsSpecialMethod (method)) {
5165                                         Report.Error (571, loc, TypeManager.CSharpSignature (method) + ": can not call operator or accessor");
5166                                         return null;
5167                                 }
5168                         }
5169
5170                         if (mg.InstanceExpression != null)
5171                                 mg.InstanceExpression.CheckMarshallByRefAccess (ec.ContainerType);
5172
5173                         eclass = ExprClass.Value;
5174                         return this;
5175                 }
5176
5177                 // <summary>
5178                 //   Emits the list of arguments as an array
5179                 // </summary>
5180                 static void EmitParams (EmitContext ec, int idx, ArrayList arguments)
5181                 {
5182                         ILGenerator ig = ec.ig;
5183                         int count = arguments.Count - idx;
5184                         Argument a = (Argument) arguments [idx];
5185                         Type t = a.Expr.Type;
5186
5187                         IntConstant.EmitInt (ig, count);
5188                         ig.Emit (OpCodes.Newarr, TypeManager.TypeToCoreType (t));
5189
5190                         int top = arguments.Count;
5191                         for (int j = idx; j < top; j++){
5192                                 a = (Argument) arguments [j];
5193
5194                                 ig.Emit (OpCodes.Dup);
5195                                 IntConstant.EmitInt (ig, j - idx);
5196
5197                                 bool is_stobj;
5198                                 OpCode op = ArrayAccess.GetStoreOpcode (t, out is_stobj);
5199                                 if (is_stobj)
5200                                         ig.Emit (OpCodes.Ldelema, t);
5201
5202                                 a.Emit (ec);
5203
5204                                 if (is_stobj)
5205                                         ig.Emit (OpCodes.Stobj, t);
5206                                 else
5207                                         ig.Emit (op);
5208                         }
5209                 }
5210
5211                 /// <summary>
5212                 ///   Emits a list of resolved Arguments that are in the arguments
5213                 ///   ArrayList.
5214                 ///
5215                 ///   The MethodBase argument might be null if the
5216                 ///   emission of the arguments is known not to contain
5217                 ///   a `params' field (for example in constructors or other routines
5218                 ///   that keep their arguments in this structure)
5219                 ///
5220                 ///   if `dup_args' is true, a copy of the arguments will be left
5221                 ///   on the stack. If `dup_args' is true, you can specify `this_arg'
5222                 ///   which will be duplicated before any other args. Only EmitCall
5223                 ///   should be using this interface.
5224                 /// </summary>
5225                 public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments, bool dup_args, LocalTemporary this_arg)
5226                 {
5227                         ParameterData pd;
5228                         if (mb != null)
5229                                 pd = GetParameterData (mb);
5230                         else
5231                                 pd = null;
5232
5233                         LocalTemporary [] temps = null;
5234
5235                         if (dup_args)
5236                                 temps = new LocalTemporary [arguments.Count];
5237
5238                         //
5239                         // If we are calling a params method with no arguments, special case it
5240                         //
5241                         if (arguments == null){
5242                                 if (pd != null && pd.Count > 0 &&
5243                                     pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
5244                                         ILGenerator ig = ec.ig;
5245
5246                                         IntConstant.EmitInt (ig, 0);
5247                                         ig.Emit (OpCodes.Newarr, TypeManager.GetElementType (pd.ParameterType (0)));
5248                                 }
5249
5250                                 return;
5251                         }
5252
5253                         int top = arguments.Count;
5254
5255                         for (int i = 0; i < top; i++){
5256                                 Argument a = (Argument) arguments [i];
5257
5258                                 if (pd != null){
5259                                         if (pd.ParameterModifier (i) == Parameter.Modifier.PARAMS){
5260                                                 //
5261                                                 // Special case if we are passing the same data as the
5262                                                 // params argument, do not put it in an array.
5263                                                 //
5264                                                 if (pd.ParameterType (i) == a.Type)
5265                                                         a.Emit (ec);
5266                                                 else
5267                                                         EmitParams (ec, i, arguments);
5268                                                 return;
5269                                         }
5270                                 }
5271
5272                                 a.Emit (ec);
5273                                 if (dup_args) {
5274                                         ec.ig.Emit (OpCodes.Dup);
5275                                         (temps [i] = new LocalTemporary (ec, a.Type)).Store (ec);
5276                                 }
5277                         }
5278
5279                         if (dup_args) {
5280                                 if (this_arg != null)
5281                                         this_arg.Emit (ec);
5282
5283                                 for (int i = 0; i < top; i ++)
5284                                         temps [i].Emit (ec);
5285                         }
5286
5287                         if (pd != null && pd.Count > top &&
5288                             pd.ParameterModifier (top) == Parameter.Modifier.PARAMS){
5289                                 ILGenerator ig = ec.ig;
5290
5291                                 IntConstant.EmitInt (ig, 0);
5292                                 ig.Emit (OpCodes.Newarr, TypeManager.GetElementType (pd.ParameterType (top)));
5293                         }
5294                 }
5295
5296                 static Type[] GetVarargsTypes (EmitContext ec, MethodBase mb,
5297                                                ArrayList arguments)
5298                 {
5299                         ParameterData pd = GetParameterData (mb);
5300
5301                         if (arguments == null)
5302                                 return new Type [0];
5303
5304                         Argument a = (Argument) arguments [pd.Count - 1];
5305                         Arglist list = (Arglist) a.Expr;
5306
5307                         return list.ArgumentTypes;
5308                 }
5309
5310                 /// <summary>
5311                 /// This checks the ConditionalAttribute on the method
5312                 /// </summary>
5313                 static bool IsMethodExcluded (MethodBase method, EmitContext ec)
5314                 {
5315                         if (method.IsConstructor)
5316                                 return false;
5317
5318                         IMethodData md = TypeManager.GetMethod (method);
5319                         if (md != null)
5320                                 return md.IsExcluded (ec);
5321
5322                         // For some methods (generated by delegate class) GetMethod returns null
5323                         // because they are not included in builder_to_method table
5324                         if (method.DeclaringType is TypeBuilder)
5325                                 return false;
5326
5327                         return AttributeTester.IsConditionalMethodExcluded (method);
5328                 }
5329
5330                 /// <remarks>
5331                 ///   is_base tells whether we want to force the use of the `call'
5332                 ///   opcode instead of using callvirt.  Call is required to call
5333                 ///   a specific method, while callvirt will always use the most
5334                 ///   recent method in the vtable.
5335                 ///
5336                 ///   is_static tells whether this is an invocation on a static method
5337                 ///
5338                 ///   instance_expr is an expression that represents the instance
5339                 ///   it must be non-null if is_static is false.
5340                 ///
5341                 ///   method is the method to invoke.
5342                 ///
5343                 ///   Arguments is the list of arguments to pass to the method or constructor.
5344                 /// </remarks>
5345                 public static void EmitCall (EmitContext ec, bool is_base,
5346                                              bool is_static, Expression instance_expr,
5347                                              MethodBase method, ArrayList Arguments, Location loc)
5348                 {
5349                         EmitCall (ec, is_base, is_static, instance_expr, method, Arguments, loc, false, false);
5350                 }
5351
5352                 // `dup_args' leaves an extra copy of the arguments on the stack
5353                 // `omit_args' does not leave any arguments at all.
5354                 // So, basically, you could make one call with `dup_args' set to true,
5355                 // and then another with `omit_args' set to true, and the two calls
5356                 // would have the same set of arguments. However, each argument would
5357                 // only have been evaluated once.
5358                 public static void EmitCall (EmitContext ec, bool is_base,
5359                                              bool is_static, Expression instance_expr,
5360                                              MethodBase method, ArrayList Arguments, Location loc,
5361                                              bool dup_args, bool omit_args)
5362                 {
5363                         ILGenerator ig = ec.ig;
5364                         bool struct_call = false;
5365                         bool this_call = false;
5366                         LocalTemporary this_arg = null;
5367
5368                         Type decl_type = method.DeclaringType;
5369
5370                         if (!RootContext.StdLib) {
5371                                 // Replace any calls to the system's System.Array type with calls to
5372                                 // the newly created one.
5373                                 if (method == TypeManager.system_int_array_get_length)
5374                                         method = TypeManager.int_array_get_length;
5375                                 else if (method == TypeManager.system_int_array_get_rank)
5376                                         method = TypeManager.int_array_get_rank;
5377                                 else if (method == TypeManager.system_object_array_clone)
5378                                         method = TypeManager.object_array_clone;
5379                                 else if (method == TypeManager.system_int_array_get_length_int)
5380                                         method = TypeManager.int_array_get_length_int;
5381                                 else if (method == TypeManager.system_int_array_get_lower_bound_int)
5382                                         method = TypeManager.int_array_get_lower_bound_int;
5383                                 else if (method == TypeManager.system_int_array_get_upper_bound_int)
5384                                         method = TypeManager.int_array_get_upper_bound_int;
5385                                 else if (method == TypeManager.system_void_array_copyto_array_int)
5386                                         method = TypeManager.void_array_copyto_array_int;
5387                         }
5388
5389                         if (ec.TestObsoleteMethodUsage) {
5390                                 //
5391                                 // This checks ObsoleteAttribute on the method and on the declaring type
5392                                 //
5393                                 ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (method);
5394                                 if (oa != null)
5395                                         AttributeTester.Report_ObsoleteMessage (oa, TypeManager.CSharpSignature (method), loc);
5396
5397
5398                                 oa = AttributeTester.GetObsoleteAttribute (method.DeclaringType);
5399                                 if (oa != null) {
5400                                         AttributeTester.Report_ObsoleteMessage (oa, method.DeclaringType.FullName, loc);
5401                                 }
5402                         }
5403
5404                         if (IsMethodExcluded (method, ec))
5405                 return;
5406
5407                         if (!is_static){
5408                                 this_call = instance_expr == null;
5409                                 if (decl_type.IsValueType || (!this_call && instance_expr.Type.IsValueType))
5410                                         struct_call = true;
5411
5412                                 //
5413                                 // If this is ourselves, push "this"
5414                                 //
5415                                 if (!omit_args) {
5416                                 Type t = null;
5417                                 if (this_call) {
5418                                         ig.Emit (OpCodes.Ldarg_0);
5419                                         t = decl_type;
5420                                 } else {
5421                                         //
5422                                         // Push the instance expression
5423                                         //
5424                                         if (instance_expr.Type.IsValueType) {
5425                                                 //
5426                                                 // Special case: calls to a function declared in a
5427                                                 // reference-type with a value-type argument need
5428                                                 // to have their value boxed.
5429                                                 if (decl_type.IsValueType) {
5430                                                         //
5431                                                         // If the expression implements IMemoryLocation, then
5432                                                         // we can optimize and use AddressOf on the
5433                                                         // return.
5434                                                         //
5435                                                         // If not we have to use some temporary storage for
5436                                                         // it.
5437                                                         if (instance_expr is IMemoryLocation) {
5438                                                                 ((IMemoryLocation)instance_expr).
5439                                                                         AddressOf (ec, AddressOp.LoadStore);
5440                                                         } else {
5441                                                                 LocalTemporary temp = new LocalTemporary (ec, instance_expr.Type);
5442                                                                 instance_expr.Emit (ec);
5443                                                                 temp.Store (ec);
5444                                                                 temp.AddressOf (ec, AddressOp.Load);
5445                                                         }
5446
5447                                                         // avoid the overhead of doing this all the time.
5448                                                         if (dup_args)
5449                                                                 t = TypeManager.GetReferenceType (instance_expr.Type);
5450                                                 } else {
5451                                                         instance_expr.Emit (ec);
5452                                                         ig.Emit (OpCodes.Box, instance_expr.Type);
5453                                                         t = TypeManager.object_type;
5454                                                 }
5455                                         } else {
5456                                                 instance_expr.Emit (ec);
5457                                                 t = instance_expr.Type;
5458                                         }
5459                                 }
5460
5461                                 if (dup_args) {
5462                                         this_arg = new LocalTemporary (ec, t);
5463                                         ig.Emit (OpCodes.Dup);
5464                                         this_arg.Store (ec);
5465                                 }
5466                                 }
5467                         }
5468
5469                         if (!omit_args)
5470                                 EmitArguments (ec, method, Arguments, dup_args, this_arg);
5471
5472                         OpCode call_op;
5473                         if (is_static || struct_call || is_base || (this_call && !method.IsVirtual))
5474                                 call_op = OpCodes.Call;
5475                         else
5476                                 call_op = OpCodes.Callvirt;
5477
5478                         if ((method.CallingConvention & CallingConventions.VarArgs) != 0) {
5479                                 Type[] varargs_types = GetVarargsTypes (ec, method, Arguments);
5480                                 ig.EmitCall (call_op, (MethodInfo) method, varargs_types);
5481                                 return;
5482                         }
5483
5484                         //
5485                         // If you have:
5486                         // this.DoFoo ();
5487                         // and DoFoo is not virtual, you can omit the callvirt,
5488                         // because you don't need the null checking behavior.
5489                         //
5490                         if (method is MethodInfo)
5491                                 ig.Emit (call_op, (MethodInfo) method);
5492                         else
5493                                 ig.Emit (call_op, (ConstructorInfo) method);
5494                 }
5495
5496                 public override void Emit (EmitContext ec)
5497                 {
5498                         MethodGroupExpr mg = (MethodGroupExpr) this.expr;
5499
5500                         EmitCall (ec, mg.IsBase, method.IsStatic, mg.InstanceExpression, method, Arguments, loc);
5501                 }
5502
5503                 public override void EmitStatement (EmitContext ec)
5504                 {
5505                         Emit (ec);
5506
5507                         //
5508                         // Pop the return value if there is one
5509                         //
5510                         if (method is MethodInfo){
5511                                 Type ret = ((MethodInfo)method).ReturnType;
5512                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
5513                                         ec.ig.Emit (OpCodes.Pop);
5514                         }
5515                 }
5516         }
5517
5518         public class InvocationOrCast : ExpressionStatement
5519         {
5520                 Expression expr;
5521                 Expression argument;
5522
5523                 public InvocationOrCast (Expression expr, Expression argument, Location loc)
5524                 {
5525                         this.expr = expr;
5526                         this.argument = argument;
5527                         this.loc = loc;
5528                 }
5529
5530                 public override Expression DoResolve (EmitContext ec)
5531                 {
5532                         //
5533                         // First try to resolve it as a cast.
5534                         //
5535                         TypeExpr te = expr.ResolveAsTypeTerminal (ec, true);
5536                         if (te != null) {
5537                                 Cast cast = new Cast (te, argument, loc);
5538                                 return cast.Resolve (ec);
5539                         }
5540
5541                         //
5542                         // This can either be a type or a delegate invocation.
5543                         // Let's just resolve it and see what we'll get.
5544                         //
5545                         expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
5546                         if (expr == null)
5547                                 return null;
5548
5549                         //
5550                         // Ok, so it's a Cast.
5551                         //
5552                         if (expr.eclass == ExprClass.Type) {
5553                                 Cast cast = new Cast (new TypeExpression (expr.Type, loc), argument, loc);
5554                                 return cast.Resolve (ec);
5555                         }
5556
5557                         //
5558                         // It's a delegate invocation.
5559                         //
5560                         if (!TypeManager.IsDelegateType (expr.Type)) {
5561                                 Error (149, "Method name expected");
5562                                 return null;
5563                         }
5564
5565                         ArrayList args = new ArrayList ();
5566                         args.Add (new Argument (argument, Argument.AType.Expression));
5567                         DelegateInvocation invocation = new DelegateInvocation (expr, args, loc);
5568                         return invocation.Resolve (ec);
5569                 }
5570
5571                 void error201 ()
5572                 {
5573                         Error (201, "Only assignment, call, increment, decrement and new object " +
5574                                "expressions can be used as a statement");
5575                 }
5576
5577                 public override ExpressionStatement ResolveStatement (EmitContext ec)
5578                 {
5579                         //
5580                         // First try to resolve it as a cast.
5581                         //
5582                         TypeExpr te = expr.ResolveAsTypeTerminal (ec, true);
5583                         if (te != null) {
5584                                 error201 ();
5585                                 return null;
5586                         }
5587
5588                         //
5589                         // This can either be a type or a delegate invocation.
5590                         // Let's just resolve it and see what we'll get.
5591                         //
5592                         expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
5593                         if ((expr == null) || (expr.eclass == ExprClass.Type)) {
5594                                 error201 ();
5595                                 return null;
5596                         }
5597
5598                         //
5599                         // It's a delegate invocation.
5600                         //
5601                         if (!TypeManager.IsDelegateType (expr.Type)) {
5602                                 Error (149, "Method name expected");
5603                                 return null;
5604                         }
5605
5606                         ArrayList args = new ArrayList ();
5607                         args.Add (new Argument (argument, Argument.AType.Expression));
5608                         DelegateInvocation invocation = new DelegateInvocation (expr, args, loc);
5609                         return invocation.ResolveStatement (ec);
5610                 }
5611
5612                 public override void Emit (EmitContext ec)
5613                 {
5614                         throw new Exception ("Cannot happen");
5615                 }
5616
5617                 public override void EmitStatement (EmitContext ec)
5618                 {
5619                         throw new Exception ("Cannot happen");
5620                 }
5621         }
5622
5623         //
5624         // This class is used to "disable" the code generation for the
5625         // temporary variable when initializing value types.
5626         //
5627         class EmptyAddressOf : EmptyExpression, IMemoryLocation {
5628                 public void AddressOf (EmitContext ec, AddressOp Mode)
5629                 {
5630                         // nothing
5631                 }
5632         }
5633
5634         /// <summary>
5635         ///    Implements the new expression
5636         /// </summary>
5637         public class New : ExpressionStatement, IMemoryLocation {
5638                 public readonly ArrayList Arguments;
5639
5640                 //
5641                 // During bootstrap, it contains the RequestedType,
5642                 // but if `type' is not null, it *might* contain a NewDelegate
5643                 // (because of field multi-initialization)
5644                 //
5645                 public Expression RequestedType;
5646
5647                 MethodBase method = null;
5648
5649                 //
5650                 // If set, the new expression is for a value_target, and
5651                 // we will not leave anything on the stack.
5652                 //
5653                 Expression value_target;
5654                 bool value_target_set = false;
5655
5656                 public New (Expression requested_type, ArrayList arguments, Location l)
5657                 {
5658                         RequestedType = requested_type;
5659                         Arguments = arguments;
5660                         loc = l;
5661                 }
5662
5663                 public bool SetValueTypeVariable (Expression value)
5664                 {
5665                         value_target = value;
5666                         value_target_set = true;
5667                         if (!(value_target is IMemoryLocation)){
5668                                 Error_UnexpectedKind ("variable", loc);
5669                                 return false;
5670                         }
5671                         return true;
5672                 }
5673
5674                 //
5675                 // This function is used to disable the following code sequence for
5676                 // value type initialization:
5677                 //
5678                 // AddressOf (temporary)
5679                 // Construct/Init
5680                 // LoadTemporary
5681                 //
5682                 // Instead the provide will have provided us with the address on the
5683                 // stack to store the results.
5684                 //
5685                 static Expression MyEmptyExpression;
5686
5687                 public void DisableTemporaryValueType ()
5688                 {
5689                         if (MyEmptyExpression == null)
5690                                 MyEmptyExpression = new EmptyAddressOf ();
5691
5692                         //
5693                         // To enable this, look into:
5694                         // test-34 and test-89 and self bootstrapping.
5695                         //
5696                         // For instance, we can avoid a copy by using `newobj'
5697                         // instead of Call + Push-temp on value types.
5698 //                      value_target = MyEmptyExpression;
5699                 }
5700
5701                 public override Expression DoResolve (EmitContext ec)
5702                 {
5703                         //
5704                         // The New DoResolve might be called twice when initializing field
5705                         // expressions (see EmitFieldInitializers, the call to
5706                         // GetInitializerExpression will perform a resolve on the expression,
5707                         // and later the assign will trigger another resolution
5708                         //
5709                         // This leads to bugs (#37014)
5710                         //
5711                         if (type != null){
5712                                 if (RequestedType is NewDelegate)
5713                                         return RequestedType;
5714                                 return this;
5715                         }
5716
5717                         TypeExpr texpr = RequestedType.ResolveAsTypeTerminal (ec, false);
5718                         if (texpr == null)
5719                                 return null;
5720
5721                         type = texpr.ResolveType (ec);
5722
5723                         CheckObsoleteAttribute (type);
5724
5725                         bool IsDelegate = TypeManager.IsDelegateType (type);
5726
5727                         if (IsDelegate){
5728                                 RequestedType = (new NewDelegate (type, Arguments, loc)).Resolve (ec);
5729                                 if (RequestedType != null)
5730                                         if (!(RequestedType is DelegateCreation))
5731                                                 throw new Exception ("NewDelegate.Resolve returned a non NewDelegate: " + RequestedType.GetType ());
5732                                 return RequestedType;
5733                         }
5734
5735                         if (type.IsAbstract && type.IsSealed) {
5736                                 Report.Error (712, loc, "Cannot create an instance of the static class '{0}'", TypeManager.CSharpName (type));
5737                                 return null;
5738                         }
5739
5740                         if (type.IsInterface || type.IsAbstract){
5741                                 Error (144, "It is not possible to create instances of interfaces or abstract classes");
5742                                 return null;
5743                         }
5744
5745                         bool is_struct = type.IsValueType;
5746                         eclass = ExprClass.Value;
5747
5748                         //
5749                         // SRE returns a match for .ctor () on structs (the object constructor),
5750                         // so we have to manually ignore it.
5751                         //
5752                         if (is_struct && Arguments == null)
5753                                 return this;
5754
5755                         Expression ml;
5756                         // For member-lookup, treat 'new Foo (bar)' as call to 'foo.ctor (bar)', where 'foo' is of type 'Foo'.
5757                         ml = MemberLookupFinal (ec, type, type, ".ctor",
5758                                                 MemberTypes.Constructor,
5759                                                 AllBindingFlags | BindingFlags.DeclaredOnly, loc);
5760
5761                         if (ml == null)
5762                                 return null;
5763
5764                         if (! (ml is MethodGroupExpr)){
5765                                 if (!is_struct){
5766                                         ml.Error_UnexpectedKind ("method group", loc);
5767                                         return null;
5768                                 }
5769                         }
5770
5771                         if (ml != null) {
5772                                 if (Arguments != null){
5773                                         foreach (Argument a in Arguments){
5774                                                 if (!a.Resolve (ec, loc))
5775                                                         return null;
5776                                         }
5777                                 }
5778
5779                                 method = Invocation.OverloadResolve (
5780                                         ec, (MethodGroupExpr) ml, Arguments, false, loc);
5781
5782                         }
5783
5784                         if (method == null) {
5785                                 if (!is_struct || Arguments.Count > 0) {
5786                                         Error (1501, String.Format (
5787                                             "New invocation: Can not find a constructor in `{0}' for this argument list",
5788                                             TypeManager.CSharpName (type)));
5789                                         return null;
5790                                 }
5791                         }
5792
5793                         return this;
5794                 }
5795
5796                 //
5797                 // This DoEmit can be invoked in two contexts:
5798                 //    * As a mechanism that will leave a value on the stack (new object)
5799                 //    * As one that wont (init struct)
5800                 //
5801                 // You can control whether a value is required on the stack by passing
5802                 // need_value_on_stack.  The code *might* leave a value on the stack
5803                 // so it must be popped manually
5804                 //
5805                 // If we are dealing with a ValueType, we have a few
5806                 // situations to deal with:
5807                 //
5808                 //    * The target is a ValueType, and we have been provided
5809                 //      the instance (this is easy, we are being assigned).
5810                 //
5811                 //    * The target of New is being passed as an argument,
5812                 //      to a boxing operation or a function that takes a
5813                 //      ValueType.
5814                 //
5815                 //      In this case, we need to create a temporary variable
5816                 //      that is the argument of New.
5817                 //
5818                 // Returns whether a value is left on the stack
5819                 //
5820                 bool DoEmit (EmitContext ec, bool need_value_on_stack)
5821                 {
5822                         bool is_value_type = type.IsValueType;
5823                         ILGenerator ig = ec.ig;
5824
5825                         if (is_value_type){
5826                                 IMemoryLocation ml;
5827
5828                                 // Allow DoEmit() to be called multiple times.
5829                                 // We need to create a new LocalTemporary each time since
5830                                 // you can't share LocalBuilders among ILGeneators.
5831                                 if (!value_target_set)
5832                                         value_target = new LocalTemporary (ec, type);
5833
5834                                 ml = (IMemoryLocation) value_target;
5835                                 ml.AddressOf (ec, AddressOp.Store);
5836                         }
5837
5838                         if (method != null)
5839                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
5840
5841                         if (is_value_type){
5842                                 if (method == null)
5843                                         ig.Emit (OpCodes.Initobj, type);
5844                                 else
5845                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
5846                                 if (need_value_on_stack){
5847                                         value_target.Emit (ec);
5848                                         return true;
5849                                 }
5850                                 return false;
5851                         } else {
5852                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) method);
5853                                 return true;
5854                         }
5855                 }
5856
5857                 public override void Emit (EmitContext ec)
5858                 {
5859                         DoEmit (ec, true);
5860                 }
5861
5862                 public override void EmitStatement (EmitContext ec)
5863                 {
5864                         if (DoEmit (ec, false))
5865                                 ec.ig.Emit (OpCodes.Pop);
5866                 }
5867
5868                 public void AddressOf (EmitContext ec, AddressOp Mode)
5869                 {
5870                         if (!type.IsValueType){
5871                                 //
5872                                 // We throw an exception.  So far, I believe we only need to support
5873                                 // value types:
5874                                 // foreach (int j in new StructType ())
5875                                 // see bug 42390
5876                                 //
5877                                 throw new Exception ("AddressOf should not be used for classes");
5878                         }
5879
5880                         if (!value_target_set)
5881                                 value_target = new LocalTemporary (ec, type);
5882
5883                         IMemoryLocation ml = (IMemoryLocation) value_target;
5884                         ml.AddressOf (ec, AddressOp.Store);
5885                         if (method != null)
5886                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
5887
5888                         if (method == null)
5889                                 ec.ig.Emit (OpCodes.Initobj, type);
5890                         else
5891                                 ec.ig.Emit (OpCodes.Call, (ConstructorInfo) method);
5892
5893                         ((IMemoryLocation) value_target).AddressOf (ec, Mode);
5894                 }
5895         }
5896
5897         /// <summary>
5898         ///   14.5.10.2: Represents an array creation expression.
5899         /// </summary>
5900         ///
5901         /// <remarks>
5902         ///   There are two possible scenarios here: one is an array creation
5903         ///   expression that specifies the dimensions and optionally the
5904         ///   initialization data and the other which does not need dimensions
5905         ///   specified but where initialization data is mandatory.
5906         /// </remarks>
5907         public class ArrayCreation : Expression {
5908                 Expression requested_base_type;
5909                 ArrayList initializers;
5910
5911                 //
5912                 // The list of Argument types.
5913                 // This is used to construct the `newarray' or constructor signature
5914                 //
5915                 ArrayList arguments;
5916
5917                 //
5918                 // Method used to create the array object.
5919                 //
5920                 MethodBase new_method = null;
5921
5922                 Type array_element_type;
5923                 Type underlying_type;
5924                 bool is_one_dimensional = false;
5925                 bool is_builtin_type = false;
5926                 bool expect_initializers = false;
5927                 int num_arguments = 0;
5928                 int dimensions = 0;
5929                 string rank;
5930
5931                 ArrayList array_data;
5932
5933                 Hashtable bounds;
5934
5935                 //
5936                 // The number of array initializers that we can handle
5937                 // via the InitializeArray method - through EmitStaticInitializers
5938                 //
5939                 int num_automatic_initializers;
5940
5941                 const int max_automatic_initializers = 6;
5942
5943                 public ArrayCreation (Expression requested_base_type, ArrayList exprs, string rank, ArrayList initializers, Location l)
5944                 {
5945                         this.requested_base_type = requested_base_type;
5946                         this.initializers = initializers;
5947                         this.rank = rank;
5948                         loc = l;
5949
5950                         arguments = new ArrayList ();
5951
5952                         foreach (Expression e in exprs) {
5953                                 arguments.Add (new Argument (e, Argument.AType.Expression));
5954                                 num_arguments++;
5955                         }
5956                 }
5957
5958                 public ArrayCreation (Expression requested_base_type, string rank, ArrayList initializers, Location l)
5959                 {
5960                         this.requested_base_type = requested_base_type;
5961                         this.initializers = initializers;
5962                         this.rank = rank;
5963                         loc = l;
5964
5965                         //this.rank = rank.Substring (0, rank.LastIndexOf ('['));
5966                         //
5967                         //string tmp = rank.Substring (rank.LastIndexOf ('['));
5968                         //
5969                         //dimensions = tmp.Length - 1;
5970                         expect_initializers = true;
5971                 }
5972
5973                 public Expression FormArrayType (Expression base_type, int idx_count, string rank)
5974                 {
5975                         StringBuilder sb = new StringBuilder (rank);
5976
5977                         sb.Append ("[");
5978                         for (int i = 1; i < idx_count; i++)
5979                                 sb.Append (",");
5980
5981                         sb.Append ("]");
5982
5983                         return new ComposedCast (base_type, sb.ToString (), loc);
5984                 }
5985
5986                 void Error_IncorrectArrayInitializer ()
5987                 {
5988                         Error (178, "Incorrectly structured array initializer");
5989                 }
5990
5991                 public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
5992                 {
5993                         if (specified_dims) {
5994                                 Argument a = (Argument) arguments [idx];
5995
5996                                 if (!a.Resolve (ec, loc))
5997                                         return false;
5998
5999                                 if (!(a.Expr is Constant)) {
6000                                         Error (150, "A constant value is expected");
6001                                         return false;
6002                                 }
6003
6004                                 int value = (int) ((Constant) a.Expr).GetValue ();
6005
6006                                 if (value != probe.Count) {
6007                                         Error_IncorrectArrayInitializer ();
6008                                         return false;
6009                                 }
6010
6011                                 bounds [idx] = value;
6012                         }
6013
6014                         int child_bounds = -1;
6015                         foreach (object o in probe) {
6016                                 if (o is ArrayList) {
6017                                         int current_bounds = ((ArrayList) o).Count;
6018
6019                                         if (child_bounds == -1)
6020                                                 child_bounds = current_bounds;
6021
6022                                         else if (child_bounds != current_bounds){
6023                                                 Error_IncorrectArrayInitializer ();
6024                                                 return false;
6025                                         }
6026                                         if (specified_dims && (idx + 1 >= arguments.Count)){
6027                                                 Error (623, "Array initializers can only be used in a variable or field initializer, try using the new expression");
6028                                                 return false;
6029                                         }
6030
6031                                         bool ret = CheckIndices (ec, (ArrayList) o, idx + 1, specified_dims);
6032                                         if (!ret)
6033                                                 return false;
6034                                 } else {
6035                                         if (child_bounds != -1){
6036                                                 Error_IncorrectArrayInitializer ();
6037                                                 return false;
6038                                         }
6039
6040                                         Expression tmp = (Expression) o;
6041                                         tmp = tmp.Resolve (ec);
6042                                         if (tmp == null)
6043                                                 return false;
6044
6045                                         // Console.WriteLine ("I got: " + tmp);
6046                                         // Handle initialization from vars, fields etc.
6047
6048                                         Expression conv = Convert.ImplicitConversionRequired (
6049                                                 ec, tmp, underlying_type, loc);
6050
6051                                         if (conv == null)
6052                                                 return false;
6053
6054                                         if (conv is StringConstant || conv is DecimalConstant || conv is NullCast) {
6055                                                 // These are subclasses of Constant that can appear as elements of an
6056                                                 // array that cannot be statically initialized (with num_automatic_initializers
6057                                                 // > max_automatic_initializers), so num_automatic_initializers should be left as zero.
6058                                                 array_data.Add (conv);
6059                                         } else if (conv is Constant) {
6060                                                 // These are the types of Constant that can appear in arrays that can be
6061                                                 // statically allocated.
6062                                                 array_data.Add (conv);
6063                                                 num_automatic_initializers++;
6064                                         } else
6065                                                 array_data.Add (conv);
6066                                 }
6067                         }
6068
6069                         return true;
6070                 }
6071
6072                 public void UpdateIndices (EmitContext ec)
6073                 {
6074                         int i = 0;
6075                         for (ArrayList probe = initializers; probe != null;) {
6076                                 if (probe.Count > 0 && probe [0] is ArrayList) {
6077                                         Expression e = new IntConstant (probe.Count);
6078                                         arguments.Add (new Argument (e, Argument.AType.Expression));
6079
6080                                         bounds [i++] =  probe.Count;
6081
6082                                         probe = (ArrayList) probe [0];
6083
6084                                 } else {
6085                                         Expression e = new IntConstant (probe.Count);
6086                                         arguments.Add (new Argument (e, Argument.AType.Expression));
6087
6088                                         bounds [i++] = probe.Count;
6089                                         probe = null;
6090                                 }
6091                         }
6092
6093                 }
6094
6095                 public bool ValidateInitializers (EmitContext ec, Type array_type)
6096                 {
6097                         if (initializers == null) {
6098                                 if (expect_initializers)
6099                                         return false;
6100                                 else
6101                                         return true;
6102                         }
6103
6104                         if (underlying_type == null)
6105                                 return false;
6106
6107                         //
6108                         // We use this to store all the date values in the order in which we
6109                         // will need to store them in the byte blob later
6110                         //
6111                         array_data = new ArrayList ();
6112                         bounds = new Hashtable ();
6113
6114                         bool ret;
6115
6116                         if (arguments != null) {
6117                                 ret = CheckIndices (ec, initializers, 0, true);
6118                                 return ret;
6119                         } else {
6120                                 arguments = new ArrayList ();
6121
6122                                 ret = CheckIndices (ec, initializers, 0, false);
6123
6124                                 if (!ret)
6125                                         return false;
6126
6127                                 UpdateIndices (ec);
6128
6129                                 if (arguments.Count != dimensions) {
6130                                         Error_IncorrectArrayInitializer ();
6131                                         return false;
6132                                 }
6133
6134                                 return ret;
6135                         }
6136                 }
6137
6138                 //
6139                 // Converts `source' to an int, uint, long or ulong.
6140                 //
6141                 Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
6142                 {
6143                         Expression target;
6144
6145                         bool old_checked = ec.CheckState;
6146                         ec.CheckState = true;
6147
6148                         target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
6149                         if (target == null){
6150                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
6151                                 if (target == null){
6152                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
6153                                         if (target == null){
6154                                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
6155                                                 if (target == null)
6156                                                         Convert.Error_CannotImplicitConversion (loc, source.Type, TypeManager.int32_type);
6157                                         }
6158                                 }
6159                         }
6160                         ec.CheckState = old_checked;
6161
6162                         //
6163                         // Only positive constants are allowed at compile time
6164                         //
6165                         if (target is Constant){
6166                                 if (target is IntConstant){
6167                                         if (((IntConstant) target).Value < 0){
6168                                                 Expression.Error_NegativeArrayIndex (loc);
6169                                                 return null;
6170                                         }
6171                                 }
6172
6173                                 if (target is LongConstant){
6174                                         if (((LongConstant) target).Value < 0){
6175                                                 Expression.Error_NegativeArrayIndex (loc);
6176                                                 return null;
6177                                         }
6178                                 }
6179
6180                         }
6181
6182                         return target;
6183                 }
6184
6185                 //
6186                 // Creates the type of the array
6187                 //
6188                 bool LookupType (EmitContext ec)
6189                 {
6190                         StringBuilder array_qualifier = new StringBuilder (rank);
6191
6192                         //
6193                         // `In the first form allocates an array instace of the type that results
6194                         // from deleting each of the individual expression from the expression list'
6195                         //
6196                         if (num_arguments > 0) {
6197                                 array_qualifier.Append ("[");
6198                                 for (int i = num_arguments-1; i > 0; i--)
6199                                         array_qualifier.Append (",");
6200                                 array_qualifier.Append ("]");
6201                         }
6202
6203                         //
6204                         // Lookup the type
6205                         //
6206                         TypeExpr array_type_expr;
6207                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
6208                         array_type_expr = array_type_expr.ResolveAsTypeTerminal (ec, false);
6209                         if (array_type_expr == null)
6210                                 return false;
6211
6212                         type = array_type_expr.ResolveType (ec);
6213
6214                         if (!type.IsArray) {
6215                                 Error (622, "Can only use array initializer expressions to assign to array types. Try using a new expression instead.");
6216                                 return false;
6217                         }
6218                         underlying_type = TypeManager.GetElementType (type);
6219                         dimensions = type.GetArrayRank ();
6220
6221                         return true;
6222                 }
6223
6224                 public override Expression DoResolve (EmitContext ec)
6225                 {
6226                         int arg_count;
6227
6228                         if (!LookupType (ec))
6229                                 return null;
6230
6231                         //
6232                         // First step is to validate the initializers and fill
6233                         // in any missing bits
6234                         //
6235                         if (!ValidateInitializers (ec, type))
6236                                 return null;
6237
6238                         if (arguments == null)
6239                                 arg_count = 0;
6240                         else {
6241                                 arg_count = arguments.Count;
6242                                 foreach (Argument a in arguments){
6243                                         if (!a.Resolve (ec, loc))
6244                                                 return null;
6245
6246                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
6247                                         if (real_arg == null)
6248                                                 return null;
6249
6250                                         a.Expr = real_arg;
6251                                 }
6252                         }
6253
6254                         array_element_type = TypeManager.GetElementType (type);
6255
6256                         if (array_element_type.IsAbstract && array_element_type.IsSealed) {
6257                                 Report.Error (719, loc, "'{0}': array elements cannot be of static type", TypeManager.CSharpName (array_element_type));
6258                                 return null;
6259                         }
6260
6261                         if (arg_count == 1) {
6262                                 is_one_dimensional = true;
6263                                 eclass = ExprClass.Value;
6264                                 return this;
6265                         }
6266
6267                         is_builtin_type = TypeManager.IsBuiltinType (type);
6268
6269                         if (is_builtin_type) {
6270                                 Expression ml;
6271
6272                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
6273                                                    AllBindingFlags, loc);
6274
6275                                 if (!(ml is MethodGroupExpr)) {
6276                                         ml.Error_UnexpectedKind ("method group", loc);
6277                                         return null;
6278                                 }
6279
6280                                 if (ml == null) {
6281                                         Error (-6, "New invocation: Can not find a constructor for " +
6282                                                       "this argument list");
6283                                         return null;
6284                                 }
6285
6286                                 new_method = Invocation.OverloadResolve (
6287                                         ec, (MethodGroupExpr) ml, arguments, false, loc);
6288
6289                                 if (new_method == null) {
6290                                         Error (-6, "New invocation: Can not find a constructor for " +
6291                                                       "this argument list");
6292                                         return null;
6293                                 }
6294
6295                                 eclass = ExprClass.Value;
6296                                 return this;
6297                         } else {
6298                                 ModuleBuilder mb = CodeGen.Module.Builder;
6299                                 ArrayList args = new ArrayList ();
6300
6301                                 if (arguments != null) {
6302                                         for (int i = 0; i < arg_count; i++)
6303                                                 args.Add (TypeManager.int32_type);
6304                                 }
6305
6306                                 Type [] arg_types = null;
6307
6308                                 if (args.Count > 0)
6309                                         arg_types = new Type [args.Count];
6310
6311                                 args.CopyTo (arg_types, 0);
6312
6313                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
6314                                                             arg_types);
6315
6316                                 if (new_method == null) {
6317                                         Error (-6, "New invocation: Can not find a constructor for " +
6318                                                       "this argument list");
6319                                         return null;
6320                                 }
6321
6322                                 eclass = ExprClass.Value;
6323                                 return this;
6324                         }
6325                 }
6326
6327                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
6328                 {
6329                         int factor;
6330                         byte [] data;
6331                         byte [] element;
6332                         int count = array_data.Count;
6333
6334                         if (underlying_type.IsEnum)
6335                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
6336
6337                         factor = GetTypeSize (underlying_type);
6338                         if (factor == 0)
6339                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
6340
6341                         data = new byte [(count * factor + 4) & ~3];
6342                         int idx = 0;
6343
6344                         for (int i = 0; i < count; ++i) {
6345                                 object v = array_data [i];
6346
6347                                 if (v is EnumConstant)
6348                                         v = ((EnumConstant) v).Child;
6349
6350                                 if (v is Constant && !(v is StringConstant))
6351                                         v = ((Constant) v).GetValue ();
6352                                 else {
6353                                         idx += factor;
6354                                         continue;
6355                                 }
6356
6357                                 if (underlying_type == TypeManager.int64_type){
6358                                         if (!(v is Expression)){
6359                                                 long val = (long) v;
6360
6361                                                 for (int j = 0; j < factor; ++j) {
6362                                                         data [idx + j] = (byte) (val & 0xFF);
6363                                                         val = (val >> 8);
6364                                                 }
6365                                         }
6366                                 } else if (underlying_type == TypeManager.uint64_type){
6367                                         if (!(v is Expression)){
6368                                                 ulong val = (ulong) v;
6369
6370                                                 for (int j = 0; j < factor; ++j) {
6371                                                         data [idx + j] = (byte) (val & 0xFF);
6372                                                         val = (val >> 8);
6373                                                 }
6374                                         }
6375                                 } else if (underlying_type == TypeManager.float_type) {
6376                                         if (!(v is Expression)){
6377                                                 element = BitConverter.GetBytes ((float) v);
6378
6379                                                 for (int j = 0; j < factor; ++j)
6380                                                         data [idx + j] = element [j];
6381                                         }
6382                                 } else if (underlying_type == TypeManager.double_type) {
6383                                         if (!(v is Expression)){
6384                                                 element = BitConverter.GetBytes ((double) v);
6385
6386                                                 for (int j = 0; j < factor; ++j)
6387                                                         data [idx + j] = element [j];
6388                                         }
6389                                 } else if (underlying_type == TypeManager.char_type){
6390                                         if (!(v is Expression)){
6391                                                 int val = (int) ((char) v);
6392
6393                                                 data [idx] = (byte) (val & 0xff);
6394                                                 data [idx+1] = (byte) (val >> 8);
6395                                         }
6396                                 } else if (underlying_type == TypeManager.short_type){
6397                                         if (!(v is Expression)){
6398                                                 int val = (int) ((short) v);
6399
6400                                                 data [idx] = (byte) (val & 0xff);
6401                                                 data [idx+1] = (byte) (val >> 8);
6402                                         }
6403                                 } else if (underlying_type == TypeManager.ushort_type){
6404                                         if (!(v is Expression)){
6405                                                 int val = (int) ((ushort) v);
6406
6407                                                 data [idx] = (byte) (val & 0xff);
6408                                                 data [idx+1] = (byte) (val >> 8);
6409                                         }
6410                                 } else if (underlying_type == TypeManager.int32_type) {
6411                                         if (!(v is Expression)){
6412                                                 int val = (int) v;
6413
6414                                                 data [idx]   = (byte) (val & 0xff);
6415                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6416                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6417                                                 data [idx+3] = (byte) (val >> 24);
6418                                         }
6419                                 } else if (underlying_type == TypeManager.uint32_type) {
6420                                         if (!(v is Expression)){
6421                                                 uint val = (uint) v;
6422
6423                                                 data [idx]   = (byte) (val & 0xff);
6424                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6425                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6426                                                 data [idx+3] = (byte) (val >> 24);
6427                                         }
6428                                 } else if (underlying_type == TypeManager.sbyte_type) {
6429                                         if (!(v is Expression)){
6430                                                 sbyte val = (sbyte) v;
6431                                                 data [idx] = (byte) val;
6432                                         }
6433                                 } else if (underlying_type == TypeManager.byte_type) {
6434                                         if (!(v is Expression)){
6435                                                 byte val = (byte) v;
6436                                                 data [idx] = (byte) val;
6437                                         }
6438                                 } else if (underlying_type == TypeManager.bool_type) {
6439                                         if (!(v is Expression)){
6440                                                 bool val = (bool) v;
6441                                                 data [idx] = (byte) (val ? 1 : 0);
6442                                         }
6443                                 } else if (underlying_type == TypeManager.decimal_type){
6444                                         if (!(v is Expression)){
6445                                                 int [] bits = Decimal.GetBits ((decimal) v);
6446                                                 int p = idx;
6447
6448                                                 // FIXME: For some reason, this doesn't work on the MS runtime.
6449                                                 int [] nbits = new int [4];
6450                                                 nbits [0] = bits [3];
6451                                                 nbits [1] = bits [2];
6452                                                 nbits [2] = bits [0];
6453                                                 nbits [3] = bits [1];
6454
6455                                                 for (int j = 0; j < 4; j++){
6456                                                         data [p++] = (byte) (nbits [j] & 0xff);
6457                                                         data [p++] = (byte) ((nbits [j] >> 8) & 0xff);
6458                                                         data [p++] = (byte) ((nbits [j] >> 16) & 0xff);
6459                                                         data [p++] = (byte) (nbits [j] >> 24);
6460                                                 }
6461                                         }
6462                                 } else
6463                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
6464
6465                                 idx += factor;
6466                         }
6467
6468                         return data;
6469                 }
6470
6471                 //
6472                 // Emits the initializers for the array
6473                 //
6474                 void EmitStaticInitializers (EmitContext ec)
6475                 {
6476                         //
6477                         // First, the static data
6478                         //
6479                         FieldBuilder fb;
6480                         ILGenerator ig = ec.ig;
6481
6482                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
6483
6484                         fb = RootContext.MakeStaticData (data);
6485
6486                         ig.Emit (OpCodes.Dup);
6487                         ig.Emit (OpCodes.Ldtoken, fb);
6488                         ig.Emit (OpCodes.Call,
6489                                  TypeManager.void_initializearray_array_fieldhandle);
6490                 }
6491
6492                 //
6493                 // Emits pieces of the array that can not be computed at compile
6494                 // time (variables and string locations).
6495                 //
6496                 // This always expect the top value on the stack to be the array
6497                 //
6498                 void EmitDynamicInitializers (EmitContext ec)
6499                 {
6500                         ILGenerator ig = ec.ig;
6501                         int dims = bounds.Count;
6502                         int [] current_pos = new int [dims];
6503                         int top = array_data.Count;
6504
6505                         MethodInfo set = null;
6506
6507                         if (dims != 1){
6508                                 Type [] args;
6509                                 ModuleBuilder mb = null;
6510                                 mb = CodeGen.Module.Builder;
6511                                 args = new Type [dims + 1];
6512
6513                                 int j;
6514                                 for (j = 0; j < dims; j++)
6515                                         args [j] = TypeManager.int32_type;
6516
6517                                 args [j] = array_element_type;
6518
6519                                 set = mb.GetArrayMethod (
6520                                         type, "Set",
6521                                         CallingConventions.HasThis | CallingConventions.Standard,
6522                                         TypeManager.void_type, args);
6523                         }
6524
6525                         for (int i = 0; i < top; i++){
6526
6527                                 Expression e = null;
6528
6529                                 if (array_data [i] is Expression)
6530                                         e = (Expression) array_data [i];
6531
6532                                 if (e != null) {
6533                                         //
6534                                         // Basically we do this for string literals and
6535                                         // other non-literal expressions
6536                                         //
6537                                         if (e is EnumConstant){
6538                                                 e = ((EnumConstant) e).Child;
6539                                         }
6540
6541                                         if (e is StringConstant || e is DecimalConstant || !(e is Constant) ||
6542                                             num_automatic_initializers <= max_automatic_initializers) {
6543                                                 Type etype = e.Type;
6544
6545                                                 ig.Emit (OpCodes.Dup);
6546
6547                                                 for (int idx = 0; idx < dims; idx++)
6548                                                         IntConstant.EmitInt (ig, current_pos [idx]);
6549
6550                                                 //
6551                                                 // If we are dealing with a struct, get the
6552                                                 // address of it, so we can store it.
6553                                                 //
6554                                                 if ((dims == 1) &&
6555                                                     etype.IsSubclassOf (TypeManager.value_type) &&
6556                                                     (!TypeManager.IsBuiltinOrEnum (etype) ||
6557                                                      etype == TypeManager.decimal_type)) {
6558                                                         if (e is New){
6559                                                                 New n = (New) e;
6560
6561                                                                 //
6562                                                                 // Let new know that we are providing
6563                                                                 // the address where to store the results
6564                                                                 //
6565                                                                 n.DisableTemporaryValueType ();
6566                                                         }
6567
6568                                                         ig.Emit (OpCodes.Ldelema, etype);
6569                                                 }
6570
6571                                                 e.Emit (ec);
6572
6573                                                 if (dims == 1) {
6574                                                         bool is_stobj;
6575                                                         OpCode op = ArrayAccess.GetStoreOpcode (etype, out is_stobj);
6576                                                         if (is_stobj)
6577                                                                 ig.Emit (OpCodes.Stobj, etype);
6578                                                         else
6579                                                                 ig.Emit (op);
6580                                                 } else
6581                                                         ig.Emit (OpCodes.Call, set);
6582
6583                                         }
6584                                 }
6585
6586                                 //
6587                                 // Advance counter
6588                                 //
6589                                 for (int j = dims - 1; j >= 0; j--){
6590                                         current_pos [j]++;
6591                                         if (current_pos [j] < (int) bounds [j])
6592                                                 break;
6593                                         current_pos [j] = 0;
6594                                 }
6595                         }
6596                 }
6597
6598                 void EmitArrayArguments (EmitContext ec)
6599                 {
6600                         ILGenerator ig = ec.ig;
6601
6602                         foreach (Argument a in arguments) {
6603                                 Type atype = a.Type;
6604                                 a.Emit (ec);
6605
6606                                 if (atype == TypeManager.uint64_type)
6607                                         ig.Emit (OpCodes.Conv_Ovf_U4);
6608                                 else if (atype == TypeManager.int64_type)
6609                                         ig.Emit (OpCodes.Conv_Ovf_I4);
6610                         }
6611                 }
6612
6613                 public override void Emit (EmitContext ec)
6614                 {
6615                         ILGenerator ig = ec.ig;
6616
6617                         EmitArrayArguments (ec);
6618                         if (is_one_dimensional)
6619                                 ig.Emit (OpCodes.Newarr, array_element_type);
6620                         else {
6621                                 if (is_builtin_type)
6622                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
6623                                 else
6624                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
6625                         }
6626
6627                         if (initializers != null){
6628                                 //
6629                                 // FIXME: Set this variable correctly.
6630                                 //
6631                                 bool dynamic_initializers = true;
6632
6633                                 // This will never be true for array types that cannot be statically
6634                                 // initialized. num_automatic_initializers will always be zero.  See
6635                                 // CheckIndices.
6636                                 if (num_automatic_initializers > max_automatic_initializers)
6637                                         EmitStaticInitializers (ec);
6638
6639                                 if (dynamic_initializers)
6640                                         EmitDynamicInitializers (ec);
6641                         }
6642                 }
6643
6644                 public object EncodeAsAttribute ()
6645                 {
6646                         if (!is_one_dimensional){
6647                                 Report.Error (-211, Location, "attribute can not encode multi-dimensional arrays");
6648                                 return null;
6649                         }
6650
6651                         if (array_data == null){
6652                                 Report.Error (-212, Location, "array should be initialized when passing it to an attribute");
6653                                 return null;
6654                         }
6655
6656                         object [] ret = new object [array_data.Count];
6657                         int i = 0;
6658                         foreach (Expression e in array_data){
6659                                 object v;
6660
6661                                 if (e is NullLiteral)
6662                                         v = null;
6663                                 else {
6664                                         if (!Attribute.GetAttributeArgumentExpression (e, Location, array_element_type, out v))
6665                                                 return null;
6666                                 }
6667                                 ret [i++] = v;
6668                         }
6669                         return ret;
6670                 }
6671         }
6672
6673         /// <summary>
6674         ///   Represents the `this' construct
6675         /// </summary>
6676         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
6677
6678                 Block block;
6679                 VariableInfo variable_info;
6680
6681                 public This (Block block, Location loc)
6682                 {
6683                         this.loc = loc;
6684                         this.block = block;
6685                 }
6686
6687                 public This (Location loc)
6688                 {
6689                         this.loc = loc;
6690                 }
6691
6692                 public VariableInfo VariableInfo {
6693                         get { return variable_info; }
6694                 }
6695
6696                 public bool VerifyFixed (bool is_expression)
6697                 {
6698                         if ((variable_info == null) || (variable_info.LocalInfo == null))
6699                                 return false;
6700                         else
6701                                 return variable_info.LocalInfo.IsFixed;
6702                 }
6703
6704                 public bool ResolveBase (EmitContext ec)
6705                 {
6706                         eclass = ExprClass.Variable;
6707                         type = ec.ContainerType;
6708
6709                         if (ec.IsStatic) {
6710                                 Error (26, "Keyword this not valid in static code");
6711                                 return false;
6712                         }
6713
6714                         if ((block != null) && (block.ThisVariable != null))
6715                                 variable_info = block.ThisVariable.VariableInfo;
6716
6717                         return true;
6718                 }
6719
6720                 public override Expression DoResolve (EmitContext ec)
6721                 {
6722                         if (!ResolveBase (ec))
6723                                 return null;
6724
6725                         if ((variable_info != null) && !variable_info.IsAssigned (ec)) {
6726                                 Error (188, "The this object cannot be used before all " +
6727                                        "of its fields are assigned to");
6728                                 variable_info.SetAssigned (ec);
6729                                 return this;
6730                         }
6731
6732                         if (ec.IsFieldInitializer) {
6733                                 Error (27, "Keyword `this' can't be used outside a constructor, " +
6734                                        "a method or a property.");
6735                                 return null;
6736                         }
6737
6738                         return this;
6739                 }
6740
6741                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
6742                 {
6743                         if (!ResolveBase (ec))
6744                                 return null;
6745
6746                         if (variable_info != null)
6747                                 variable_info.SetAssigned (ec);
6748
6749                         if (ec.TypeContainer is Class){
6750                                 Error (1604, "Cannot assign to `this'");
6751                                 return null;
6752                         }
6753
6754                         return this;
6755                 }
6756
6757                 public void Emit (EmitContext ec, bool leave_copy)
6758                 {
6759                         Emit (ec);
6760                         if (leave_copy)
6761                                 ec.ig.Emit (OpCodes.Dup);
6762                 }
6763
6764                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
6765                 {
6766                         ILGenerator ig = ec.ig;
6767
6768                         if (ec.TypeContainer is Struct){
6769                                 ec.EmitThis ();
6770                                 source.Emit (ec);
6771                                 if (leave_copy)
6772                                         ec.ig.Emit (OpCodes.Dup);
6773                                 ig.Emit (OpCodes.Stobj, type);
6774                         } else {
6775                                 throw new Exception ("how did you get here");
6776                         }
6777                 }
6778
6779                 public override void Emit (EmitContext ec)
6780                 {
6781                         ILGenerator ig = ec.ig;
6782
6783                         ec.EmitThis ();
6784                         if (ec.TypeContainer is Struct)
6785                                 ig.Emit (OpCodes.Ldobj, type);
6786                 }
6787
6788                 public void AddressOf (EmitContext ec, AddressOp mode)
6789                 {
6790                         ec.EmitThis ();
6791
6792                         // FIMXE
6793                         // FIGURE OUT WHY LDARG_S does not work
6794                         //
6795                         // consider: struct X { int val; int P { set { val = value; }}}
6796                         //
6797                         // Yes, this looks very bad. Look at `NOTAS' for
6798                         // an explanation.
6799                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
6800                 }
6801         }
6802
6803         /// <summary>
6804         ///   Represents the `__arglist' construct
6805         /// </summary>
6806         public class ArglistAccess : Expression
6807         {
6808                 public ArglistAccess (Location loc)
6809                 {
6810                         this.loc = loc;
6811                 }
6812
6813                 public bool ResolveBase (EmitContext ec)
6814                 {
6815                         eclass = ExprClass.Variable;
6816                         type = TypeManager.runtime_argument_handle_type;
6817                         return true;
6818                 }
6819
6820                 public override Expression DoResolve (EmitContext ec)
6821                 {
6822                         if (!ResolveBase (ec))
6823                                 return null;
6824
6825                         if (ec.IsFieldInitializer || !ec.CurrentBlock.HasVarargs) {
6826                                 Error (190, "The __arglist construct is valid only within " +
6827                                        "a variable argument method.");
6828                                 return null;
6829                         }
6830
6831                         return this;
6832                 }
6833
6834                 public override void Emit (EmitContext ec)
6835                 {
6836                         ec.ig.Emit (OpCodes.Arglist);
6837                 }
6838         }
6839
6840         /// <summary>
6841         ///   Represents the `__arglist (....)' construct
6842         /// </summary>
6843         public class Arglist : Expression
6844         {
6845                 public readonly Argument[] Arguments;
6846
6847                 public Arglist (Argument[] args, Location l)
6848                 {
6849                         Arguments = args;
6850                         loc = l;
6851                 }
6852
6853                 public Type[] ArgumentTypes {
6854                         get {
6855                                 Type[] retval = new Type [Arguments.Length];
6856                                 for (int i = 0; i < Arguments.Length; i++)
6857                                         retval [i] = Arguments [i].Type;
6858                                 return retval;
6859                         }
6860                 }
6861
6862                 public override Expression DoResolve (EmitContext ec)
6863                 {
6864                         eclass = ExprClass.Variable;
6865                         type = TypeManager.runtime_argument_handle_type;
6866
6867                         foreach (Argument arg in Arguments) {
6868                                 if (!arg.Resolve (ec, loc))
6869                                         return null;
6870                         }
6871
6872                         return this;
6873                 }
6874
6875                 public override void Emit (EmitContext ec)
6876                 {
6877                         foreach (Argument arg in Arguments)
6878                                 arg.Emit (ec);
6879                 }
6880         }
6881
6882         //
6883         // This produces the value that renders an instance, used by the iterators code
6884         //
6885         public class ProxyInstance : Expression, IMemoryLocation  {
6886                 public override Expression DoResolve (EmitContext ec)
6887                 {
6888                         eclass = ExprClass.Variable;
6889                         type = ec.ContainerType;
6890                         return this;
6891                 }
6892
6893                 public override void Emit (EmitContext ec)
6894                 {
6895                         ec.ig.Emit (OpCodes.Ldarg_0);
6896
6897                 }
6898
6899                 public void AddressOf (EmitContext ec, AddressOp mode)
6900                 {
6901                         ec.ig.Emit (OpCodes.Ldarg_0);
6902                 }
6903         }
6904
6905         /// <summary>
6906         ///   Implements the typeof operator
6907         /// </summary>
6908         public class TypeOf : Expression {
6909                 public Expression QueriedType;
6910                 protected Type typearg;
6911
6912                 public TypeOf (Expression queried_type, Location l)
6913                 {
6914                         QueriedType = queried_type;
6915                         loc = l;
6916                 }
6917
6918                 public override Expression DoResolve (EmitContext ec)
6919                 {
6920                         TypeExpr texpr = QueriedType.ResolveAsTypeTerminal (ec, false);
6921                         if (texpr == null)
6922                                 return null;
6923
6924                         typearg = texpr.ResolveType (ec);
6925
6926                         if (typearg == TypeManager.void_type) {
6927                                 Error (673, "System.Void cannot be used from C# - " +
6928                                        "use typeof (void) to get the void type object");
6929                                 return null;
6930                         }
6931
6932                         if (typearg.IsPointer && !ec.InUnsafe){
6933                                 UnsafeError (loc);
6934                                 return null;
6935                         }
6936                         CheckObsoleteAttribute (typearg);
6937
6938                         type = TypeManager.type_type;
6939                         eclass = ExprClass.Type;
6940                         return this;
6941                 }
6942
6943                 public override void Emit (EmitContext ec)
6944                 {
6945                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
6946                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
6947                 }
6948
6949                 public Type TypeArg {
6950                         get { return typearg; }
6951                 }
6952         }
6953
6954         /// <summary>
6955         ///   Implements the `typeof (void)' operator
6956         /// </summary>
6957         public class TypeOfVoid : TypeOf {
6958                 public TypeOfVoid (Location l) : base (null, l)
6959                 {
6960                         loc = l;
6961                 }
6962
6963                 public override Expression DoResolve (EmitContext ec)
6964                 {
6965                         type = TypeManager.type_type;
6966                         typearg = TypeManager.void_type;
6967                         eclass = ExprClass.Type;
6968                         return this;
6969                 }
6970         }
6971
6972         /// <summary>
6973         ///   Implements the sizeof expression
6974         /// </summary>
6975         public class SizeOf : Expression {
6976                 public Expression QueriedType;
6977                 Type type_queried;
6978
6979                 public SizeOf (Expression queried_type, Location l)
6980                 {
6981                         this.QueriedType = queried_type;
6982                         loc = l;
6983                 }
6984
6985                 public override Expression DoResolve (EmitContext ec)
6986                 {
6987                         if (!ec.InUnsafe) {
6988                                 Report.Error (
6989                                         233, loc, "Sizeof may only be used in an unsafe context " +
6990                                         "(consider using System.Runtime.InteropServices.Marshal.SizeOf");
6991                                 return null;
6992                         }
6993
6994                         TypeExpr texpr = QueriedType.ResolveAsTypeTerminal (ec, false);
6995                         if (texpr == null)
6996                                 return null;
6997
6998                         type_queried = texpr.ResolveType (ec);
6999
7000                         CheckObsoleteAttribute (type_queried);
7001
7002                         if (!TypeManager.IsUnmanagedType (type_queried)){
7003                                 Report.Error (208, loc, "Cannot take the size of an unmanaged type (" + TypeManager.CSharpName (type_queried) + ")");
7004                                 return null;
7005                         }
7006
7007                         type = TypeManager.int32_type;
7008                         eclass = ExprClass.Value;
7009                         return this;
7010                 }
7011
7012                 public override void Emit (EmitContext ec)
7013                 {
7014                         int size = GetTypeSize (type_queried);
7015
7016                         if (size == 0)
7017                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
7018                         else
7019                                 IntConstant.EmitInt (ec.ig, size);
7020                 }
7021         }
7022
7023         /// <summary>
7024         ///   Implements the member access expression
7025         /// </summary>
7026         public class MemberAccess : Expression {
7027                 public readonly string Identifier;
7028                 Expression expr;
7029
7030                 public MemberAccess (Expression expr, string id, Location l)
7031                 {
7032                         this.expr = expr;
7033                         Identifier = id;
7034                         loc = l;
7035                 }
7036
7037                 public Expression Expr {
7038                         get {
7039                                 return expr;
7040                         }
7041                 }
7042
7043                 public static void error176 (Location loc, string name)
7044                 {
7045                         Report.Error (176, loc, "Static member `" +
7046                                       name + "' cannot be accessed " +
7047                                       "with an instance reference, qualify with a " +
7048                                       "type name instead");
7049                 }
7050
7051                 public static bool IdenticalNameAndTypeName (EmitContext ec, Expression left_original, Expression left, Location loc)
7052                 {
7053                         SimpleName sn = left_original as SimpleName;
7054                         if (sn == null || left == null || left.Type.Name != sn.Name)
7055                                 return false;
7056
7057                         return RootContext.LookupType (ec.DeclSpace, sn.Name, true, loc) != null;
7058                 }
7059
7060                 // TODO: possible optimalization
7061                 // Cache resolved constant result in FieldBuilder <-> expresion map
7062                 public static Expression ResolveMemberAccess (EmitContext ec, Expression member_lookup,
7063                                                               Expression left, Location loc,
7064                                                               Expression left_original)
7065                 {
7066                         bool left_is_type, left_is_explicit;
7067
7068                         // If `left' is null, then we're called from SimpleNameResolve and this is
7069                         // a member in the currently defining class.
7070                         if (left == null) {
7071                                 left_is_type = ec.IsStatic || ec.IsFieldInitializer;
7072                                 left_is_explicit = false;
7073
7074                                 // Implicitly default to `this' unless we're static.
7075                                 if (!ec.IsStatic && !ec.IsFieldInitializer && !ec.InEnumContext)
7076                                         left = ec.GetThis (loc);
7077                         } else {
7078                                 left_is_type = left is TypeExpr;
7079                                 left_is_explicit = true;
7080                         }
7081
7082                         if (member_lookup is FieldExpr){
7083                                 FieldExpr fe = (FieldExpr) member_lookup;
7084                                 FieldInfo fi = fe.FieldInfo;
7085                                 Type decl_type = fi.DeclaringType;
7086
7087                                 bool is_emitted = fi is FieldBuilder;
7088                                 Type t = fi.FieldType;
7089
7090                                 if (is_emitted) {
7091                                         Const c = TypeManager.LookupConstant ((FieldBuilder) fi);
7092
7093                                         if (c != null) {
7094                                                 object o;
7095                                                 if (!c.LookupConstantValue (out o))
7096                                                         return null;
7097
7098                                                 object real_value = ((Constant) c.Expr).GetValue ();
7099
7100                                                 return Constantify (real_value, t);
7101                                         }
7102                                 }
7103
7104                                 // IsInitOnly is because of MS compatibility, I don't know why but they emit decimal constant as InitOnly
7105                                 if (fi.IsInitOnly && !is_emitted && t == TypeManager.decimal_type) {
7106                                         object[] attrs = fi.GetCustomAttributes (TypeManager.decimal_constant_attribute_type, false);
7107                                         if (attrs.Length == 1)
7108                                                 return new DecimalConstant (((System.Runtime.CompilerServices.DecimalConstantAttribute) attrs [0]).Value);
7109                                 }
7110
7111                                 if (fi.IsLiteral) {
7112                                         object o;
7113
7114                                         if (is_emitted)
7115                                                 o = TypeManager.GetValue ((FieldBuilder) fi);
7116                                         else
7117                                                 o = fi.GetValue (fi);
7118
7119                                         if (decl_type.IsSubclassOf (TypeManager.enum_type)) {
7120                                                 if (left_is_explicit && !left_is_type &&
7121                                                     !IdenticalNameAndTypeName (ec, left_original, member_lookup, loc)) {
7122                                                         error176 (loc, fe.FieldInfo.Name);
7123                                                         return null;
7124                                                 }
7125
7126                                                 Expression enum_member = MemberLookup (
7127                                                         ec, decl_type, "value__", MemberTypes.Field,
7128                                                         AllBindingFlags, loc);
7129
7130                                                 Enum en = TypeManager.LookupEnum (decl_type);
7131
7132                                                 Constant c;
7133                                                 if (en != null)
7134                                                         c = Constantify (o, en.UnderlyingType);
7135                                                 else
7136                                                         c = Constantify (o, enum_member.Type);
7137
7138                                                 return new EnumConstant (c, decl_type);
7139                                         }
7140
7141                                         Expression exp = Constantify (o, t);
7142
7143                                         if (left_is_explicit && !left_is_type) {
7144                                                 error176 (loc, fe.FieldInfo.Name);
7145                                                 return null;
7146                                         }
7147
7148                                         return exp;
7149                                 }
7150
7151                                 if (t.IsPointer && !ec.InUnsafe){
7152                                         UnsafeError (loc);
7153                                         return null;
7154                                 }
7155                         }
7156
7157                         if (member_lookup is EventExpr) {
7158                                 EventExpr ee = (EventExpr) member_lookup;
7159
7160                                 //
7161                                 // If the event is local to this class, we transform ourselves into
7162                                 // a FieldExpr
7163                                 //
7164
7165                                 if (ee.EventInfo.DeclaringType == ec.ContainerType ||
7166                                     TypeManager.IsNestedChildOf(ec.ContainerType, ee.EventInfo.DeclaringType)) {
7167                                         MemberInfo mi = GetFieldFromEvent (ee);
7168
7169                                         if (mi == null) {
7170                                                 //
7171                                                 // If this happens, then we have an event with its own
7172                                                 // accessors and private field etc so there's no need
7173                                                 // to transform ourselves.
7174                                                 //
7175                                                 ee.InstanceExpression = left;
7176                                                 return ee;
7177                                         }
7178
7179                                         Expression ml = ExprClassFromMemberInfo (ec, mi, loc);
7180
7181                                         if (ml == null) {
7182                                                 Report.Error (-200, loc, "Internal error!!");
7183                                                 return null;
7184                                         }
7185
7186                                         if (!left_is_explicit)
7187                                                 left = null;
7188
7189                                         ee.InstanceExpression = left;
7190
7191                                         return ResolveMemberAccess (ec, ml, left, loc, left_original);
7192                                 }
7193                         }
7194
7195                         if (member_lookup is IMemberExpr) {
7196                                 IMemberExpr me = (IMemberExpr) member_lookup;
7197                                 MethodGroupExpr mg = me as MethodGroupExpr;
7198
7199                                 if (left_is_type){
7200                                         if ((mg != null) && left_is_explicit && left.Type.IsInterface)
7201                                                 mg.IsExplicitImpl = left_is_explicit;
7202
7203                                         if (!me.IsStatic){
7204                                                 if ((ec.IsFieldInitializer || ec.IsStatic) &&
7205                                                     IdenticalNameAndTypeName (ec, left_original, member_lookup, loc))
7206                                                         return member_lookup;
7207
7208                                                 SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
7209                                                 return null;
7210                                         }
7211
7212                                 } else {
7213                                         if (!me.IsInstance) {
7214                                                 if (IdenticalNameAndTypeName (ec, left_original, left, loc))
7215                                                         return member_lookup;
7216
7217                                                 if (left_is_explicit) {
7218                                                         error176 (loc, me.Name);
7219                                                         return null;
7220                                                 }
7221                                         }
7222
7223                                         //
7224                                         // Since we can not check for instance objects in SimpleName,
7225                                         // becaue of the rule that allows types and variables to share
7226                                         // the name (as long as they can be de-ambiguated later, see
7227                                         // IdenticalNameAndTypeName), we have to check whether left
7228                                         // is an instance variable in a static context
7229                                         //
7230                                         // However, if the left-hand value is explicitly given, then
7231                                         // it is already our instance expression, so we aren't in
7232                                         // static context.
7233                                         //
7234
7235                                         if (ec.IsStatic && !left_is_explicit && left is IMemberExpr){
7236                                                 IMemberExpr mexp = (IMemberExpr) left;
7237
7238                                                 if (!mexp.IsStatic){
7239                                                         SimpleName.Error_ObjectRefRequired (ec, loc, mexp.Name);
7240                                                         return null;
7241                                                 }
7242                                         }
7243
7244                                         if ((mg != null) && IdenticalNameAndTypeName (ec, left_original, left, loc))
7245                                                 mg.IdenticalTypeName = true;
7246
7247                                         me.InstanceExpression = left;
7248                                 }
7249
7250                                 return member_lookup;
7251                         }
7252
7253                         Console.WriteLine ("Left is: " + left);
7254                         Report.Error (-100, loc, "Support for [" + member_lookup + "] is not present yet");
7255                         Environment.Exit (1);
7256                         return null;
7257                 }
7258
7259                 public Expression DoResolve (EmitContext ec, Expression right_side, ResolveFlags flags)
7260                 {
7261                         if (type != null)
7262                                 throw new Exception ();
7263
7264                         //
7265                         // Resolve the expression with flow analysis turned off, we'll do the definite
7266                         // assignment checks later.  This is because we don't know yet what the expression
7267                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
7268                         // definite assignment check on the actual field and not on the whole struct.
7269                         //
7270
7271                         Expression original = expr;
7272                         expr = expr.Resolve (ec, flags | ResolveFlags.Intermediate | ResolveFlags.DisableFlowAnalysis);
7273                         if (expr == null)
7274                                 return null;
7275
7276                         if (expr is SimpleName){
7277                                 SimpleName child_expr = (SimpleName) expr;
7278
7279                                 Expression new_expr = new SimpleName (child_expr.Name, Identifier, loc);
7280
7281                                 return new_expr.Resolve (ec, flags);
7282                         }
7283
7284                         //
7285                         // TODO: I mailed Ravi about this, and apparently we can get rid
7286                         // of this and put it in the right place.
7287                         //
7288                         // Handle enums here when they are in transit.
7289                         // Note that we cannot afford to hit MemberLookup in this case because
7290                         // it will fail to find any members at all
7291                         //
7292
7293                         Type expr_type = expr.Type;
7294                         if (expr is TypeExpr){
7295                                 if (!ec.DeclSpace.CheckAccessLevel (expr_type)){
7296                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", expr_type);
7297                                         return null;
7298                                 }
7299
7300                                 if (expr_type == TypeManager.enum_type || expr_type.IsSubclassOf (TypeManager.enum_type)){
7301                                         Enum en = TypeManager.LookupEnum (expr_type);
7302
7303                                         if (en != null) {
7304                                                 object value = en.LookupEnumValue (ec, Identifier, loc);
7305
7306                                                 if (value != null){
7307                                                         MemberCore mc = en.GetDefinition (Identifier);
7308                                                         ObsoleteAttribute oa = mc.GetObsoleteAttribute (en);
7309                                                         if (oa != null) {
7310                                                                 AttributeTester.Report_ObsoleteMessage (oa, mc.GetSignatureForError (), Location);
7311                                                         }
7312                                                         oa = en.GetObsoleteAttribute (en);
7313                                                         if (oa != null) {
7314                                                                 AttributeTester.Report_ObsoleteMessage (oa, en.GetSignatureForError (), Location);
7315                                                         }
7316
7317                                                         Constant c = Constantify (value, en.UnderlyingType);
7318                                                         return new EnumConstant (c, expr_type);
7319                                                 }
7320                                         } else {
7321                                                 CheckObsoleteAttribute (expr_type);
7322
7323                                                 FieldInfo fi = expr_type.GetField (Identifier);
7324                                                 if (fi != null) {
7325                                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (fi);
7326                                                         if (oa != null)
7327                                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (fi), Location);
7328                                                 }
7329                                         }
7330                                 }
7331                         }
7332
7333                         if (expr_type.IsPointer){
7334                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7335                                        TypeManager.CSharpName (expr_type) + ")");
7336                                 return null;
7337                         }
7338
7339                         Expression member_lookup;
7340                         member_lookup = MemberLookupFinal (ec, expr_type, expr_type, Identifier, loc);
7341                         if (member_lookup == null)
7342                                 return null;
7343
7344                         if (member_lookup is TypeExpr) {
7345                                 if (!(expr is TypeExpr) && !(expr is SimpleName)) {
7346                                         Error (572, "Can't reference type `" + Identifier + "' through an expression; try `" +
7347                                                member_lookup.Type + "' instead");
7348                                         return null;
7349                                 }
7350
7351                                 return member_lookup;
7352                         }
7353
7354                         member_lookup = ResolveMemberAccess (ec, member_lookup, expr, loc, original);
7355                         if (member_lookup == null)
7356                                 return null;
7357
7358                         // The following DoResolve/DoResolveLValue will do the definite assignment
7359                         // check.
7360
7361                         if (right_side != null)
7362                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
7363                         else
7364                                 member_lookup = member_lookup.DoResolve (ec);
7365
7366                         return member_lookup;
7367                 }
7368
7369                 public override Expression DoResolve (EmitContext ec)
7370                 {
7371                         return DoResolve (ec, null, ResolveFlags.VariableOrValue |
7372                                           ResolveFlags.SimpleName | ResolveFlags.Type);
7373                 }
7374
7375                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7376                 {
7377                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue |
7378                                           ResolveFlags.SimpleName | ResolveFlags.Type);
7379                 }
7380
7381                 public override Expression ResolveAsTypeStep (EmitContext ec)
7382                 {
7383                         string fname = null;
7384                         MemberAccess full_expr = this;
7385                         while (full_expr != null) {
7386                                 if (fname != null)
7387                                         fname = String.Concat (full_expr.Identifier, ".", fname);
7388                                 else
7389                                         fname = full_expr.Identifier;
7390
7391                                 if (full_expr.Expr is SimpleName) {
7392                                         string full_name = String.Concat (((SimpleName) full_expr.Expr).Name, ".", fname);
7393                                         Type fully_qualified = ec.DeclSpace.FindType (loc, full_name);
7394                                         if (fully_qualified != null)
7395                                                 return new TypeExpression (fully_qualified, loc);
7396                                 }
7397
7398                                 full_expr = full_expr.Expr as MemberAccess;
7399                         }
7400
7401                         Expression new_expr = expr.ResolveAsTypeStep (ec);
7402
7403                         if (new_expr == null)
7404                                 return null;
7405
7406                         if (new_expr is SimpleName){
7407                                 SimpleName child_expr = (SimpleName) new_expr;
7408
7409                                 new_expr = new SimpleName (child_expr.Name, Identifier, loc);
7410
7411                                 return new_expr.ResolveAsTypeStep (ec);
7412                         }
7413
7414                         Type expr_type = new_expr.Type;
7415
7416                         if (expr_type.IsPointer){
7417                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7418                                        TypeManager.CSharpName (expr_type) + ")");
7419                                 return null;
7420                         }
7421
7422                         Expression member_lookup;
7423                         member_lookup = MemberLookupFinal (ec, expr_type, expr_type, Identifier, loc);
7424                         if (member_lookup == null)
7425                                 return null;
7426
7427                         if (member_lookup is TypeExpr){
7428                                 member_lookup.Resolve (ec, ResolveFlags.Type);
7429                                 return member_lookup;
7430                         }
7431
7432                         return null;
7433                 }
7434
7435                 public override void Emit (EmitContext ec)
7436                 {
7437                         throw new Exception ("Should not happen");
7438                 }
7439
7440                 public override string ToString ()
7441                 {
7442                         return expr + "." + Identifier;
7443                 }
7444         }
7445
7446         /// <summary>
7447         ///   Implements checked expressions
7448         /// </summary>
7449         public class CheckedExpr : Expression {
7450
7451                 public Expression Expr;
7452
7453                 public CheckedExpr (Expression e, Location l)
7454                 {
7455                         Expr = e;
7456                         loc = l;
7457                 }
7458
7459                 public override Expression DoResolve (EmitContext ec)
7460                 {
7461                         bool last_check = ec.CheckState;
7462                         bool last_const_check = ec.ConstantCheckState;
7463
7464                         ec.CheckState = true;
7465                         ec.ConstantCheckState = true;
7466                         Expr = Expr.Resolve (ec);
7467                         ec.CheckState = last_check;
7468                         ec.ConstantCheckState = last_const_check;
7469
7470                         if (Expr == null)
7471                                 return null;
7472
7473                         if (Expr is Constant)
7474                                 return Expr;
7475
7476                         eclass = Expr.eclass;
7477                         type = Expr.Type;
7478                         return this;
7479                 }
7480
7481                 public override void Emit (EmitContext ec)
7482                 {
7483                         bool last_check = ec.CheckState;
7484                         bool last_const_check = ec.ConstantCheckState;
7485
7486                         ec.CheckState = true;
7487                         ec.ConstantCheckState = true;
7488                         Expr.Emit (ec);
7489                         ec.CheckState = last_check;
7490                         ec.ConstantCheckState = last_const_check;
7491                 }
7492
7493         }
7494
7495         /// <summary>
7496         ///   Implements the unchecked expression
7497         /// </summary>
7498         public class UnCheckedExpr : Expression {
7499
7500                 public Expression Expr;
7501
7502                 public UnCheckedExpr (Expression e, Location l)
7503                 {
7504                         Expr = e;
7505                         loc = l;
7506                 }
7507
7508                 public override Expression DoResolve (EmitContext ec)
7509                 {
7510                         bool last_check = ec.CheckState;
7511                         bool last_const_check = ec.ConstantCheckState;
7512
7513                         ec.CheckState = false;
7514                         ec.ConstantCheckState = false;
7515                         Expr = Expr.Resolve (ec);
7516                         ec.CheckState = last_check;
7517                         ec.ConstantCheckState = last_const_check;
7518
7519                         if (Expr == null)
7520                                 return null;
7521
7522                         if (Expr is Constant)
7523                                 return Expr;
7524
7525                         eclass = Expr.eclass;
7526                         type = Expr.Type;
7527                         return this;
7528                 }
7529
7530                 public override void Emit (EmitContext ec)
7531                 {
7532                         bool last_check = ec.CheckState;
7533                         bool last_const_check = ec.ConstantCheckState;
7534
7535                         ec.CheckState = false;
7536                         ec.ConstantCheckState = false;
7537                         Expr.Emit (ec);
7538                         ec.CheckState = last_check;
7539                         ec.ConstantCheckState = last_const_check;
7540                 }
7541
7542         }
7543
7544         /// <summary>
7545         ///   An Element Access expression.
7546         ///
7547         ///   During semantic analysis these are transformed into
7548         ///   IndexerAccess, ArrayAccess or a PointerArithmetic.
7549         /// </summary>
7550         public class ElementAccess : Expression {
7551                 public ArrayList  Arguments;
7552                 public Expression Expr;
7553
7554                 public ElementAccess (Expression e, ArrayList e_list, Location l)
7555                 {
7556                         Expr = e;
7557
7558                         loc  = l;
7559
7560                         if (e_list == null)
7561                                 return;
7562
7563                         Arguments = new ArrayList ();
7564                         foreach (Expression tmp in e_list)
7565                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
7566
7567                 }
7568
7569                 bool CommonResolve (EmitContext ec)
7570                 {
7571                         Expr = Expr.Resolve (ec);
7572
7573                         if (Expr == null)
7574                                 return false;
7575
7576                         if (Arguments == null)
7577                                 return false;
7578
7579                         foreach (Argument a in Arguments){
7580                                 if (!a.Resolve (ec, loc))
7581                                         return false;
7582                         }
7583
7584                         return true;
7585                 }
7586
7587                 Expression MakePointerAccess (EmitContext ec)
7588                 {
7589                         Type t = Expr.Type;
7590
7591                         if (t == TypeManager.void_ptr_type){
7592                                 Error (242, "The array index operation is not valid for void pointers");
7593                                 return null;
7594                         }
7595                         if (Arguments.Count != 1){
7596                                 Error (196, "A pointer must be indexed by a single value");
7597                                 return null;
7598                         }
7599                         Expression p;
7600
7601                         p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr, t, loc).Resolve (ec);
7602                         if (p == null)
7603                                 return null;
7604                         return new Indirection (p, loc).Resolve (ec);
7605                 }
7606
7607                 public override Expression DoResolve (EmitContext ec)
7608                 {
7609                         if (!CommonResolve (ec))
7610                                 return null;
7611
7612                         //
7613                         // We perform some simple tests, and then to "split" the emit and store
7614                         // code we create an instance of a different class, and return that.
7615                         //
7616                         // I am experimenting with this pattern.
7617                         //
7618                         Type t = Expr.Type;
7619
7620                         if (t == TypeManager.array_type){
7621                                 Report.Error (21, loc, "Cannot use indexer on System.Array");
7622                                 return null;
7623                         }
7624
7625                         if (t.IsArray)
7626                                 return (new ArrayAccess (this, loc)).Resolve (ec);
7627                         else if (t.IsPointer)
7628                                 return MakePointerAccess (ec);
7629                         else
7630                                 return (new IndexerAccess (this, loc)).Resolve (ec);
7631                 }
7632
7633                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7634                 {
7635                         if (!CommonResolve (ec))
7636                                 return null;
7637
7638                         Type t = Expr.Type;
7639                         if (t.IsArray)
7640                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
7641                         else if (t.IsPointer)
7642                                 return MakePointerAccess (ec);
7643                         else
7644                                 return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
7645                 }
7646
7647                 public override void Emit (EmitContext ec)
7648                 {
7649                         throw new Exception ("Should never be reached");
7650                 }
7651         }
7652
7653         /// <summary>
7654         ///   Implements array access
7655         /// </summary>
7656         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
7657                 //
7658                 // Points to our "data" repository
7659                 //
7660                 ElementAccess ea;
7661
7662                 LocalTemporary temp;
7663                 bool prepared;
7664
7665                 public ArrayAccess (ElementAccess ea_data, Location l)
7666                 {
7667                         ea = ea_data;
7668                         eclass = ExprClass.Variable;
7669                         loc = l;
7670                 }
7671
7672                 public override Expression DoResolve (EmitContext ec)
7673                 {
7674 #if false
7675                         ExprClass eclass = ea.Expr.eclass;
7676
7677                         // As long as the type is valid
7678                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
7679                               eclass == ExprClass.Value)) {
7680                                 ea.Expr.Error_UnexpectedKind ("variable or value");
7681                                 return null;
7682                         }
7683 #endif
7684
7685                         Type t = ea.Expr.Type;
7686                         if (t.GetArrayRank () != ea.Arguments.Count){
7687                                 ea.Error (22,
7688                                           "Incorrect number of indexes for array " +
7689                                           " expected: " + t.GetArrayRank () + " got: " +
7690                                           ea.Arguments.Count);
7691                                 return null;
7692                         }
7693
7694                         type = TypeManager.GetElementType (t);
7695                         if (type.IsPointer && !ec.InUnsafe){
7696                                 UnsafeError (ea.Location);
7697                                 return null;
7698                         }
7699
7700                         foreach (Argument a in ea.Arguments){
7701                                 Type argtype = a.Type;
7702
7703                                 if (argtype == TypeManager.int32_type ||
7704                                     argtype == TypeManager.uint32_type ||
7705                                     argtype == TypeManager.int64_type ||
7706                                     argtype == TypeManager.uint64_type) {
7707                                         Constant c = a.Expr as Constant;
7708                                         if (c != null && c.IsNegative) {
7709                                                 Report.Warning (251, 2, a.Expr.Location, "Indexing an array with a negative index (array indices always start at zero)");
7710                                         }
7711                                         continue;
7712                                 }
7713
7714                                 //
7715                                 // Mhm.  This is strage, because the Argument.Type is not the same as
7716                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
7717                                 //
7718                                 // Wonder if I will run into trouble for this.
7719                                 //
7720                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
7721                                 if (a.Expr == null)
7722                                         return null;
7723                         }
7724
7725                         eclass = ExprClass.Variable;
7726
7727                         return this;
7728                 }
7729
7730                 /// <summary>
7731                 ///    Emits the right opcode to load an object of Type `t'
7732                 ///    from an array of T
7733                 /// </summary>
7734                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
7735                 {
7736                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
7737                                 ig.Emit (OpCodes.Ldelem_U1);
7738                         else if (type == TypeManager.sbyte_type)
7739                                 ig.Emit (OpCodes.Ldelem_I1);
7740                         else if (type == TypeManager.short_type)
7741                                 ig.Emit (OpCodes.Ldelem_I2);
7742                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
7743                                 ig.Emit (OpCodes.Ldelem_U2);
7744                         else if (type == TypeManager.int32_type)
7745                                 ig.Emit (OpCodes.Ldelem_I4);
7746                         else if (type == TypeManager.uint32_type)
7747                                 ig.Emit (OpCodes.Ldelem_U4);
7748                         else if (type == TypeManager.uint64_type)
7749                                 ig.Emit (OpCodes.Ldelem_I8);
7750                         else if (type == TypeManager.int64_type)
7751                                 ig.Emit (OpCodes.Ldelem_I8);
7752                         else if (type == TypeManager.float_type)
7753                                 ig.Emit (OpCodes.Ldelem_R4);
7754                         else if (type == TypeManager.double_type)
7755                                 ig.Emit (OpCodes.Ldelem_R8);
7756                         else if (type == TypeManager.intptr_type)
7757                                 ig.Emit (OpCodes.Ldelem_I);
7758                         else if (TypeManager.IsEnumType (type)){
7759                                 EmitLoadOpcode (ig, TypeManager.EnumToUnderlying (type));
7760                         } else if (type.IsValueType){
7761                                 ig.Emit (OpCodes.Ldelema, type);
7762                                 ig.Emit (OpCodes.Ldobj, type);
7763                         } else
7764                                 ig.Emit (OpCodes.Ldelem_Ref);
7765                 }
7766
7767                 /// <summary>
7768                 ///    Returns the right opcode to store an object of Type `t'
7769                 ///    from an array of T.
7770                 /// </summary>
7771                 static public OpCode GetStoreOpcode (Type t, out bool is_stobj)
7772                 {
7773                         //Console.WriteLine (new System.Diagnostics.StackTrace ());
7774                         is_stobj = false;
7775                         t = TypeManager.TypeToCoreType (t);
7776                         if (TypeManager.IsEnumType (t))
7777                                 t = TypeManager.EnumToUnderlying (t);
7778                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
7779                             t == TypeManager.bool_type)
7780                                 return OpCodes.Stelem_I1;
7781                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type ||
7782                                  t == TypeManager.char_type)
7783                                 return OpCodes.Stelem_I2;
7784                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
7785                                 return OpCodes.Stelem_I4;
7786                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
7787                                 return OpCodes.Stelem_I8;
7788                         else if (t == TypeManager.float_type)
7789                                 return OpCodes.Stelem_R4;
7790                         else if (t == TypeManager.double_type)
7791                                 return OpCodes.Stelem_R8;
7792                         else if (t == TypeManager.intptr_type) {
7793                                 is_stobj = true;
7794                                 return OpCodes.Stobj;
7795                         } else if (t.IsValueType) {
7796                                 is_stobj = true;
7797                                 return OpCodes.Stobj;
7798                         } else
7799                                 return OpCodes.Stelem_Ref;
7800                 }
7801
7802                 MethodInfo FetchGetMethod ()
7803                 {
7804                         ModuleBuilder mb = CodeGen.Module.Builder;
7805                         int arg_count = ea.Arguments.Count;
7806                         Type [] args = new Type [arg_count];
7807                         MethodInfo get;
7808
7809                         for (int i = 0; i < arg_count; i++){
7810                                 //args [i++] = a.Type;
7811                                 args [i] = TypeManager.int32_type;
7812                         }
7813
7814                         get = mb.GetArrayMethod (
7815                                 ea.Expr.Type, "Get",
7816                                 CallingConventions.HasThis |
7817                                 CallingConventions.Standard,
7818                                 type, args);
7819                         return get;
7820                 }
7821
7822
7823                 MethodInfo FetchAddressMethod ()
7824                 {
7825                         ModuleBuilder mb = CodeGen.Module.Builder;
7826                         int arg_count = ea.Arguments.Count;
7827                         Type [] args = new Type [arg_count];
7828                         MethodInfo address;
7829                         Type ret_type;
7830
7831                         ret_type = TypeManager.GetReferenceType (type);
7832
7833                         for (int i = 0; i < arg_count; i++){
7834                                 //args [i++] = a.Type;
7835                                 args [i] = TypeManager.int32_type;
7836                         }
7837
7838                         address = mb.GetArrayMethod (
7839                                 ea.Expr.Type, "Address",
7840                                 CallingConventions.HasThis |
7841                                 CallingConventions.Standard,
7842                                 ret_type, args);
7843
7844                         return address;
7845                 }
7846
7847                 //
7848                 // Load the array arguments into the stack.
7849                 //
7850                 // If we have been requested to cache the values (cached_locations array
7851                 // initialized), then load the arguments the first time and store them
7852                 // in locals.  otherwise load from local variables.
7853                 //
7854                 void LoadArrayAndArguments (EmitContext ec)
7855                 {
7856                         ILGenerator ig = ec.ig;
7857
7858                         ea.Expr.Emit (ec);
7859                         foreach (Argument a in ea.Arguments){
7860                                 Type argtype = a.Expr.Type;
7861
7862                                 a.Expr.Emit (ec);
7863
7864                                 if (argtype == TypeManager.int64_type)
7865                                         ig.Emit (OpCodes.Conv_Ovf_I);
7866                                 else if (argtype == TypeManager.uint64_type)
7867                                         ig.Emit (OpCodes.Conv_Ovf_I_Un);
7868                         }
7869                 }
7870
7871                 public void Emit (EmitContext ec, bool leave_copy)
7872                 {
7873                         int rank = ea.Expr.Type.GetArrayRank ();
7874                         ILGenerator ig = ec.ig;
7875
7876                         if (!prepared) {
7877                                 LoadArrayAndArguments (ec);
7878
7879                                 if (rank == 1)
7880                                         EmitLoadOpcode (ig, type);
7881                                 else {
7882                                         MethodInfo method;
7883
7884                                         method = FetchGetMethod ();
7885                                         ig.Emit (OpCodes.Call, method);
7886                                 }
7887                         } else
7888                                 LoadFromPtr (ec.ig, this.type);
7889
7890                         if (leave_copy) {
7891                                 ec.ig.Emit (OpCodes.Dup);
7892                                 temp = new LocalTemporary (ec, this.type);
7893                                 temp.Store (ec);
7894                         }
7895                 }
7896
7897                 public override void Emit (EmitContext ec)
7898                 {
7899                         Emit (ec, false);
7900                 }
7901
7902                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
7903                 {
7904                         int rank = ea.Expr.Type.GetArrayRank ();
7905                         ILGenerator ig = ec.ig;
7906                         Type t = source.Type;
7907                         prepared = prepare_for_load;
7908
7909                         if (prepare_for_load) {
7910                                 AddressOf (ec, AddressOp.LoadStore);
7911                                 ec.ig.Emit (OpCodes.Dup);
7912                                 source.Emit (ec);
7913                                 if (leave_copy) {
7914                                         ec.ig.Emit (OpCodes.Dup);
7915                                         temp = new LocalTemporary (ec, this.type);
7916                                         temp.Store (ec);
7917                                 }
7918                                 StoreFromPtr (ec.ig, t);
7919
7920                                 if (temp != null)
7921                                         temp.Emit (ec);
7922
7923                                 return;
7924                         }
7925
7926                         LoadArrayAndArguments (ec);
7927
7928                         if (rank == 1) {
7929                                 bool is_stobj;
7930                                 OpCode op = GetStoreOpcode (t, out is_stobj);
7931                                 //
7932                                 // The stobj opcode used by value types will need
7933                                 // an address on the stack, not really an array/array
7934                                 // pair
7935                                 //
7936                                 if (is_stobj)
7937                                         ig.Emit (OpCodes.Ldelema, t);
7938
7939                                 source.Emit (ec);
7940                                 if (leave_copy) {
7941                                         ec.ig.Emit (OpCodes.Dup);
7942                                         temp = new LocalTemporary (ec, this.type);
7943                                         temp.Store (ec);
7944                                 }
7945
7946                                 if (is_stobj)
7947                                         ig.Emit (OpCodes.Stobj, t);
7948                                 else
7949                                         ig.Emit (op);
7950                         } else {
7951                                 ModuleBuilder mb = CodeGen.Module.Builder;
7952                                 int arg_count = ea.Arguments.Count;
7953                                 Type [] args = new Type [arg_count + 1];
7954                                 MethodInfo set;
7955
7956                                 source.Emit (ec);
7957                                 if (leave_copy) {
7958                                         ec.ig.Emit (OpCodes.Dup);
7959                                         temp = new LocalTemporary (ec, this.type);
7960                                         temp.Store (ec);
7961                                 }
7962
7963                                 for (int i = 0; i < arg_count; i++){
7964                                         //args [i++] = a.Type;
7965                                         args [i] = TypeManager.int32_type;
7966                                 }
7967
7968                                 args [arg_count] = type;
7969
7970                                 set = mb.GetArrayMethod (
7971                                         ea.Expr.Type, "Set",
7972                                         CallingConventions.HasThis |
7973                                         CallingConventions.Standard,
7974                                         TypeManager.void_type, args);
7975
7976                                 ig.Emit (OpCodes.Call, set);
7977                         }
7978
7979                         if (temp != null)
7980                                 temp.Emit (ec);
7981                 }
7982
7983                 public void AddressOf (EmitContext ec, AddressOp mode)
7984                 {
7985                         int rank = ea.Expr.Type.GetArrayRank ();
7986                         ILGenerator ig = ec.ig;
7987
7988                         LoadArrayAndArguments (ec);
7989
7990                         if (rank == 1){
7991                                 ig.Emit (OpCodes.Ldelema, type);
7992                         } else {
7993                                 MethodInfo address = FetchAddressMethod ();
7994                                 ig.Emit (OpCodes.Call, address);
7995                         }
7996                 }
7997         }
7998
7999
8000         class Indexers {
8001                 public ArrayList Properties;
8002                 static Hashtable map;
8003
8004                 public struct Indexer {
8005                         public readonly Type Type;
8006                         public readonly MethodInfo Getter, Setter;
8007
8008                         public Indexer (Type type, MethodInfo get, MethodInfo set)
8009                         {
8010                                 this.Type = type;
8011                                 this.Getter = get;
8012                                 this.Setter = set;
8013                         }
8014                 }
8015
8016                 static Indexers ()
8017                 {
8018                         map = new Hashtable ();
8019                 }
8020
8021                 Indexers ()
8022                 {
8023                         Properties = new ArrayList ();
8024                 }
8025
8026                 void Append (MemberInfo [] mi)
8027                 {
8028                         foreach (PropertyInfo property in mi){
8029                                 MethodInfo get, set;
8030
8031                                 get = property.GetGetMethod (true);
8032                                 set = property.GetSetMethod (true);
8033                                 Properties.Add (new Indexer (property.PropertyType, get, set));
8034                         }
8035                 }
8036
8037                 static private MemberInfo [] GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
8038                 {
8039                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
8040
8041                         MemberInfo [] mi = TypeManager.MemberLookup (
8042                                 caller_type, caller_type, lookup_type, MemberTypes.Property,
8043                                 BindingFlags.Public | BindingFlags.Instance |
8044                                 BindingFlags.DeclaredOnly, p_name, null);
8045
8046                         if (mi == null || mi.Length == 0)
8047                                 return null;
8048
8049                         return mi;
8050                 }
8051
8052                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
8053                 {
8054                         Indexers ix = (Indexers) map [lookup_type];
8055
8056                         if (ix != null)
8057                                 return ix;
8058
8059                         Type copy = lookup_type;
8060                         while (copy != TypeManager.object_type && copy != null){
8061                                 MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, copy);
8062
8063                                 if (mi != null){
8064                                         if (ix == null)
8065                                                 ix = new Indexers ();
8066
8067                                         ix.Append (mi);
8068                                 }
8069
8070                                 copy = copy.BaseType;
8071                         }
8072
8073                         if (!lookup_type.IsInterface)
8074                                 return ix;
8075
8076                         Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
8077                         if (ifaces != null) {
8078                                 foreach (Type itype in ifaces) {
8079                                         MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, itype);
8080                                         if (mi != null){
8081                                                 if (ix == null)
8082                                                         ix = new Indexers ();
8083
8084                                                 ix.Append (mi);
8085                                         }
8086                                 }
8087                         }
8088
8089                         return ix;
8090                 }
8091         }
8092
8093         /// <summary>
8094         ///   Expressions that represent an indexer call.
8095         /// </summary>
8096         public class IndexerAccess : Expression, IAssignMethod {
8097                 //
8098                 // Points to our "data" repository
8099                 //
8100                 MethodInfo get, set;
8101                 ArrayList set_arguments;
8102                 bool is_base_indexer;
8103
8104                 protected Type indexer_type;
8105                 protected Type current_type;
8106                 protected Expression instance_expr;
8107                 protected ArrayList arguments;
8108
8109                 public IndexerAccess (ElementAccess ea, Location loc)
8110                         : this (ea.Expr, false, loc)
8111                 {
8112                         this.arguments = ea.Arguments;
8113                 }
8114
8115                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
8116                                          Location loc)
8117                 {
8118                         this.instance_expr = instance_expr;
8119                         this.is_base_indexer = is_base_indexer;
8120                         this.eclass = ExprClass.Value;
8121                         this.loc = loc;
8122                 }
8123
8124                 protected virtual bool CommonResolve (EmitContext ec)
8125                 {
8126                         indexer_type = instance_expr.Type;
8127                         current_type = ec.ContainerType;
8128
8129                         return true;
8130                 }
8131
8132                 public override Expression DoResolve (EmitContext ec)
8133                 {
8134                         ArrayList AllGetters = new ArrayList();
8135                         if (!CommonResolve (ec))
8136                                 return null;
8137
8138                         //
8139                         // Step 1: Query for all `Item' *properties*.  Notice
8140                         // that the actual methods are pointed from here.
8141                         //
8142                         // This is a group of properties, piles of them.
8143
8144                         bool found_any = false, found_any_getters = false;
8145                         Type lookup_type = indexer_type;
8146
8147                         Indexers ilist;
8148                         ilist = Indexers.GetIndexersForType (current_type, lookup_type, loc);
8149                         if (ilist != null) {
8150                                 found_any = true;
8151                                 if (ilist.Properties != null) {
8152                                         foreach (Indexers.Indexer ix in ilist.Properties) {
8153                                                 if (ix.Getter != null)
8154                                                         AllGetters.Add(ix.Getter);
8155                                         }
8156                                 }
8157                         }
8158
8159                         if (AllGetters.Count > 0) {
8160                                 found_any_getters = true;
8161                                 get = (MethodInfo) Invocation.OverloadResolve (
8162                                         ec, new MethodGroupExpr (AllGetters, loc),
8163                                         arguments, false, loc);
8164                         }
8165
8166                         if (!found_any) {
8167                                 Report.Error (21, loc,
8168                                               "Type `" + TypeManager.CSharpName (indexer_type) +
8169                                               "' does not have any indexers defined");
8170                                 return null;
8171                         }
8172
8173                         if (!found_any_getters) {
8174                                 Error (154, "indexer can not be used in this context, because " +
8175                                        "it lacks a `get' accessor");
8176                                 return null;
8177                         }
8178
8179                         if (get == null) {
8180                                 Error (1501, "No Overload for method `this' takes `" +
8181                                        arguments.Count + "' arguments");
8182                                 return null;
8183                         }
8184
8185                         //
8186                         // Only base will allow this invocation to happen.
8187                         //
8188                         if (get.IsAbstract && this is BaseIndexerAccess){
8189                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (get));
8190                                 return null;
8191                         }
8192
8193                         type = get.ReturnType;
8194                         if (type.IsPointer && !ec.InUnsafe){
8195                                 UnsafeError (loc);
8196                                 return null;
8197                         }
8198
8199                         instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
8200
8201                         eclass = ExprClass.IndexerAccess;
8202                         return this;
8203                 }
8204
8205                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8206                 {
8207                         ArrayList AllSetters = new ArrayList();
8208                         if (!CommonResolve (ec))
8209                                 return null;
8210
8211                         bool found_any = false, found_any_setters = false;
8212
8213                         Indexers ilist = Indexers.GetIndexersForType (current_type, indexer_type, loc);
8214                         if (ilist != null) {
8215                                 found_any = true;
8216                                 if (ilist.Properties != null) {
8217                                         foreach (Indexers.Indexer ix in ilist.Properties) {
8218                                                 if (ix.Setter != null)
8219                                                         AllSetters.Add(ix.Setter);
8220                                         }
8221                                 }
8222                         }
8223                         if (AllSetters.Count > 0) {
8224                                 found_any_setters = true;
8225                                 set_arguments = (ArrayList) arguments.Clone ();
8226                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
8227                                 set = (MethodInfo) Invocation.OverloadResolve (
8228                                         ec, new MethodGroupExpr (AllSetters, loc),
8229                                         set_arguments, false, loc);
8230                         }
8231
8232                         if (!found_any) {
8233                                 Report.Error (21, loc,
8234                                               "Type `" + TypeManager.CSharpName (indexer_type) +
8235                                               "' does not have any indexers defined");
8236                                 return null;
8237                         }
8238
8239                         if (!found_any_setters) {
8240                                 Error (154, "indexer can not be used in this context, because " +
8241                                        "it lacks a `set' accessor");
8242                                 return null;
8243                         }
8244
8245                         if (set == null) {
8246                                 Error (1501, "No Overload for method `this' takes `" +
8247                                        arguments.Count + "' arguments");
8248                                 return null;
8249                         }
8250
8251                         //
8252                         // Only base will allow this invocation to happen.
8253                         //
8254                         if (set.IsAbstract && this is BaseIndexerAccess){
8255                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (set));
8256                                 return null;
8257                         }
8258
8259                         //
8260                         // Now look for the actual match in the list of indexers to set our "return" type
8261                         //
8262                         type = TypeManager.void_type;   // default value
8263                         foreach (Indexers.Indexer ix in ilist.Properties){
8264                                 if (ix.Setter == set){
8265                                         type = ix.Type;
8266                                         break;
8267                                 }
8268                         }
8269
8270                         instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
8271
8272                         eclass = ExprClass.IndexerAccess;
8273                         return this;
8274                 }
8275
8276                 bool prepared = false;
8277                 LocalTemporary temp;
8278
8279                 public void Emit (EmitContext ec, bool leave_copy)
8280                 {
8281                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, get, arguments, loc, prepared, false);
8282                         if (leave_copy) {
8283                                 ec.ig.Emit (OpCodes.Dup);
8284                                 temp = new LocalTemporary (ec, Type);
8285                                 temp.Store (ec);
8286                         }
8287                 }
8288
8289                 //
8290                 // source is ignored, because we already have a copy of it from the
8291                 // LValue resolution and we have already constructed a pre-cached
8292                 // version of the arguments (ea.set_arguments);
8293                 //
8294                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8295                 {
8296                         prepared = prepare_for_load;
8297                         Argument a = (Argument) set_arguments [set_arguments.Count - 1];
8298
8299                         if (prepared) {
8300                                 source.Emit (ec);
8301                                 if (leave_copy) {
8302                                         ec.ig.Emit (OpCodes.Dup);
8303                                         temp = new LocalTemporary (ec, Type);
8304                                         temp.Store (ec);
8305                                 }
8306                         } else if (leave_copy) {
8307                                 temp = new LocalTemporary (ec, Type);
8308                                 source.Emit (ec);
8309                                 temp.Store (ec);
8310                                 a.Expr = temp;
8311                         }
8312
8313                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, set, set_arguments, loc, false, prepared);
8314
8315                         if (temp != null)
8316                                 temp.Emit (ec);
8317                 }
8318
8319
8320                 public override void Emit (EmitContext ec)
8321                 {
8322                         Emit (ec, false);
8323                 }
8324         }
8325
8326         /// <summary>
8327         ///   The base operator for method names
8328         /// </summary>
8329         public class BaseAccess : Expression {
8330                 string member;
8331
8332                 public BaseAccess (string member, Location l)
8333                 {
8334                         this.member = member;
8335                         loc = l;
8336                 }
8337
8338                 public override Expression DoResolve (EmitContext ec)
8339                 {
8340                         Expression c = CommonResolve (ec);
8341
8342                         if (c == null)
8343                                 return null;
8344
8345                         //
8346                         // MethodGroups use this opportunity to flag an error on lacking ()
8347                         //
8348                         if (!(c is MethodGroupExpr))
8349                                 return c.Resolve (ec);
8350                         return c;
8351                 }
8352
8353                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8354                 {
8355                         Expression c = CommonResolve (ec);
8356
8357                         if (c == null)
8358                                 return null;
8359
8360                         //
8361                         // MethodGroups use this opportunity to flag an error on lacking ()
8362                         //
8363                         if (! (c is MethodGroupExpr))
8364                                 return c.DoResolveLValue (ec, right_side);
8365
8366                         return c;
8367                 }
8368
8369                 Expression CommonResolve (EmitContext ec)
8370                 {
8371                         Expression member_lookup;
8372                         Type current_type = ec.ContainerType;
8373                         Type base_type = current_type.BaseType;
8374                         Expression e;
8375
8376                         if (ec.IsStatic){
8377                                 Error (1511, "Keyword base is not allowed in static method");
8378                                 return null;
8379                         }
8380
8381                         if (ec.IsFieldInitializer){
8382                                 Error (1512, "Keyword base is not available in the current context");
8383                                 return null;
8384                         }
8385
8386                         member_lookup = MemberLookup (ec, ec.ContainerType, null, base_type, member,
8387                                                       AllMemberTypes, AllBindingFlags, loc);
8388                         if (member_lookup == null) {
8389                                 MemberLookupFailed (ec, base_type, base_type, member, null, loc);
8390                                 return null;
8391                         }
8392
8393                         Expression left;
8394
8395                         if (ec.IsStatic)
8396                                 left = new TypeExpression (base_type, loc);
8397                         else
8398                                 left = ec.GetThis (loc);
8399
8400                         e = MemberAccess.ResolveMemberAccess (ec, member_lookup, left, loc, null);
8401
8402                         if (e is PropertyExpr){
8403                                 PropertyExpr pe = (PropertyExpr) e;
8404
8405                                 pe.IsBase = true;
8406                         }
8407
8408                         if (e is MethodGroupExpr)
8409                                 ((MethodGroupExpr) e).IsBase = true;
8410
8411                         return e;
8412                 }
8413
8414                 public override void Emit (EmitContext ec)
8415                 {
8416                         throw new Exception ("Should never be called");
8417                 }
8418         }
8419
8420         /// <summary>
8421         ///   The base indexer operator
8422         /// </summary>
8423         public class BaseIndexerAccess : IndexerAccess {
8424                 public BaseIndexerAccess (ArrayList args, Location loc)
8425                         : base (null, true, loc)
8426                 {
8427                         arguments = new ArrayList ();
8428                         foreach (Expression tmp in args)
8429                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
8430                 }
8431
8432                 protected override bool CommonResolve (EmitContext ec)
8433                 {
8434                         instance_expr = ec.GetThis (loc);
8435
8436                         current_type = ec.ContainerType.BaseType;
8437                         indexer_type = current_type;
8438
8439                         foreach (Argument a in arguments){
8440                                 if (!a.Resolve (ec, loc))
8441                                         return false;
8442                         }
8443
8444                         return true;
8445                 }
8446         }
8447
8448         /// <summary>
8449         ///   This class exists solely to pass the Type around and to be a dummy
8450         ///   that can be passed to the conversion functions (this is used by
8451         ///   foreach implementation to typecast the object return value from
8452         ///   get_Current into the proper type.  All code has been generated and
8453         ///   we only care about the side effect conversions to be performed
8454         ///
8455         ///   This is also now used as a placeholder where a no-action expression
8456         ///   is needed (the `New' class).
8457         /// </summary>
8458         public class EmptyExpression : Expression {
8459                 public static readonly EmptyExpression Null = new EmptyExpression ();
8460
8461                 // TODO: should be protected
8462                 public EmptyExpression ()
8463                 {
8464                         type = TypeManager.object_type;
8465                         eclass = ExprClass.Value;
8466                         loc = Location.Null;
8467                 }
8468
8469                 public EmptyExpression (Type t)
8470                 {
8471                         type = t;
8472                         eclass = ExprClass.Value;
8473                         loc = Location.Null;
8474                 }
8475
8476                 public override Expression DoResolve (EmitContext ec)
8477                 {
8478                         return this;
8479                 }
8480
8481                 public override void Emit (EmitContext ec)
8482                 {
8483                         // nothing, as we only exist to not do anything.
8484                 }
8485
8486                 //
8487                 // This is just because we might want to reuse this bad boy
8488                 // instead of creating gazillions of EmptyExpressions.
8489                 // (CanImplicitConversion uses it)
8490                 //
8491                 public void SetType (Type t)
8492                 {
8493                         type = t;
8494                 }
8495         }
8496
8497         public class UserCast : Expression {
8498                 MethodBase method;
8499                 Expression source;
8500
8501                 public UserCast (MethodInfo method, Expression source, Location l)
8502                 {
8503                         this.method = method;
8504                         this.source = source;
8505                         type = method.ReturnType;
8506                         eclass = ExprClass.Value;
8507                         loc = l;
8508                 }
8509
8510                 public Expression Source {
8511                         get {
8512                                 return source;
8513                         }
8514                 }
8515
8516                 public override Expression DoResolve (EmitContext ec)
8517                 {
8518                         //
8519                         // We are born fully resolved
8520                         //
8521                         return this;
8522                 }
8523
8524                 public override void Emit (EmitContext ec)
8525                 {
8526                         ILGenerator ig = ec.ig;
8527
8528                         source.Emit (ec);
8529
8530                         if (method is MethodInfo)
8531                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
8532                         else
8533                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
8534
8535                 }
8536         }
8537
8538         // <summary>
8539         //   This class is used to "construct" the type during a typecast
8540         //   operation.  Since the Type.GetType class in .NET can parse
8541         //   the type specification, we just use this to construct the type
8542         //   one bit at a time.
8543         // </summary>
8544         public class ComposedCast : TypeExpr {
8545                 Expression left;
8546                 string dim;
8547
8548                 public ComposedCast (Expression left, string dim, Location l)
8549                 {
8550                         this.left = left;
8551                         this.dim = dim;
8552                         loc = l;
8553                 }
8554
8555                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
8556                 {
8557                         TypeExpr lexpr = left.ResolveAsTypeTerminal (ec, false);
8558                         if (lexpr == null)
8559                                 return null;
8560
8561                         Type ltype = lexpr.ResolveType (ec);
8562
8563                         if ((ltype == TypeManager.void_type) && (dim != "*")) {
8564                                 Report.Error (1547, Location,
8565                                               "Keyword 'void' cannot be used in this context");
8566                                 return null;
8567                         }
8568
8569                         //
8570                         // ltype.Fullname is already fully qualified, so we can skip
8571                         // a lot of probes, and go directly to TypeManager.LookupType
8572                         //
8573                         string cname = ltype.FullName + dim;
8574                         type = TypeManager.LookupTypeDirect (cname);
8575                         if (type == null){
8576                                 //
8577                                 // For arrays of enumerations we are having a problem
8578                                 // with the direct lookup.  Need to investigate.
8579                                 //
8580                                 // For now, fall back to the full lookup in that case.
8581                                 //
8582                                 type = RootContext.LookupType (ec.DeclSpace, cname, false, loc);
8583                                 if (type == null)
8584                                         return null;
8585                         }
8586
8587                         if (!ec.InUnsafe && type.IsPointer){
8588                                 UnsafeError (loc);
8589                                 return null;
8590                         }
8591
8592                         if (type.IsArray && (type.GetElementType () == TypeManager.arg_iterator_type ||
8593                                 type.GetElementType () == TypeManager.typed_reference_type)) {
8594                                 Report.Error (611, loc, "Array elements cannot be of type '{0}'", TypeManager.CSharpName (type.GetElementType ()));
8595                                 return null;
8596                         }
8597
8598                         eclass = ExprClass.Type;
8599                         return this;
8600                 }
8601
8602                 public override string Name {
8603                         get {
8604                                 return left + dim;
8605                         }
8606                 }
8607         }
8608
8609         //
8610         // This class is used to represent the address of an array, used
8611         // only by the Fixed statement, this is like the C "&a [0]" construct.
8612         //
8613         public class ArrayPtr : Expression {
8614                 Expression array;
8615
8616                 public ArrayPtr (Expression array, Location l)
8617                 {
8618                         Type array_type = TypeManager.GetElementType (array.Type);
8619
8620                         this.array = array;
8621
8622                         type = TypeManager.GetPointerType (array_type);
8623                         eclass = ExprClass.Value;
8624                         loc = l;
8625                 }
8626
8627                 public override void Emit (EmitContext ec)
8628                 {
8629                         ILGenerator ig = ec.ig;
8630
8631                         array.Emit (ec);
8632                         IntLiteral.EmitInt (ig, 0);
8633                         ig.Emit (OpCodes.Ldelema, TypeManager.GetElementType (array.Type));
8634                 }
8635
8636                 public override Expression DoResolve (EmitContext ec)
8637                 {
8638                         //
8639                         // We are born fully resolved
8640                         //
8641                         return this;
8642                 }
8643         }
8644
8645         //
8646         // Used by the fixed statement
8647         //
8648         public class StringPtr : Expression {
8649                 LocalBuilder b;
8650
8651                 public StringPtr (LocalBuilder b, Location l)
8652                 {
8653                         this.b = b;
8654                         eclass = ExprClass.Value;
8655                         type = TypeManager.char_ptr_type;
8656                         loc = l;
8657                 }
8658
8659                 public override Expression DoResolve (EmitContext ec)
8660                 {
8661                         // This should never be invoked, we are born in fully
8662                         // initialized state.
8663
8664                         return this;
8665                 }
8666
8667                 public override void Emit (EmitContext ec)
8668                 {
8669                         ILGenerator ig = ec.ig;
8670
8671                         ig.Emit (OpCodes.Ldloc, b);
8672                         ig.Emit (OpCodes.Conv_I);
8673                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
8674                         ig.Emit (OpCodes.Add);
8675                 }
8676         }
8677
8678         //
8679         // Implements the `stackalloc' keyword
8680         //
8681         public class StackAlloc : Expression {
8682                 Type otype;
8683                 Expression t;
8684                 Expression count;
8685
8686                 public StackAlloc (Expression type, Expression count, Location l)
8687                 {
8688                         t = type;
8689                         this.count = count;
8690                         loc = l;
8691                 }
8692
8693                 public override Expression DoResolve (EmitContext ec)
8694                 {
8695                         count = count.Resolve (ec);
8696                         if (count == null)
8697                                 return null;
8698
8699                         if (count.Type != TypeManager.int32_type){
8700                                 count = Convert.ImplicitConversionRequired (ec, count, TypeManager.int32_type, loc);
8701                                 if (count == null)
8702                                         return null;
8703                         }
8704
8705                         Constant c = count as Constant;
8706                         if (c != null && c.IsNegative) {
8707                                 Report.Error (247, loc, "Cannot use a negative size with stackalloc");
8708                                 return null;
8709                         }
8710
8711                         if (ec.CurrentBranching.InCatch () ||
8712                             ec.CurrentBranching.InFinally (true)) {
8713                                 Error (255,
8714                                        "stackalloc can not be used in a catch or finally block");
8715                                 return null;
8716                         }
8717
8718                         TypeExpr texpr = t.ResolveAsTypeTerminal (ec, false);
8719                         if (texpr == null)
8720                                 return null;
8721
8722                         otype = texpr.ResolveType (ec);
8723
8724                         if (!TypeManager.VerifyUnManaged (otype, loc))
8725                                 return null;
8726
8727                         type = TypeManager.GetPointerType (otype);
8728                         eclass = ExprClass.Value;
8729
8730                         return this;
8731                 }
8732
8733                 public override void Emit (EmitContext ec)
8734                 {
8735                         int size = GetTypeSize (otype);
8736                         ILGenerator ig = ec.ig;
8737
8738                         if (size == 0)
8739                                 ig.Emit (OpCodes.Sizeof, otype);
8740                         else
8741                                 IntConstant.EmitInt (ig, size);
8742                         count.Emit (ec);
8743                         ig.Emit (OpCodes.Mul);
8744                         ig.Emit (OpCodes.Localloc);
8745                 }
8746         }
8747 }