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                         return e;
 221                 }
 222
 223                 // <summary>
 224                 //   This routine will attempt to simplify the unary expression when the
 225                 //   argument is a constant.  The result is returned in `result' and the
 226                 //   function returns true or false depending on whether a reduction
 227                 //   was performed or not
 228                 // </summary>
 229                 bool Reduce (EmitContext ec, Constant e, out Expression result)
 230                 {
 231                         Type expr_type = e.Type;
 232
 233                         switch (Oper){
 234                         case Operator.UnaryPlus:
 235                                 result = e;
 236                                 return true;
 237
 238                         case Operator.UnaryNegation:
 239                                 result = TryReduceNegative (e);
 240                                 return true;
 241
 242                         case Operator.LogicalNot:
 243                                 if (expr_type != TypeManager.bool_type) {
 244                                         result = null;
 245                                         Error23 (expr_type);
 246                                         return false;
 247                                 }
 248
 249                                 BoolConstant b = (BoolConstant) e;
 250                                 result = new BoolConstant (!(b.Value));
 251                                 return true;
 252
 253                         case Operator.OnesComplement:
 254                                 if (!((expr_type == TypeManager.int32_type) ||
 255                                       (expr_type == TypeManager.uint32_type) ||
 256                                       (expr_type == TypeManager.int64_type) ||
 257                                       (expr_type == TypeManager.uint64_type) ||
 258                                       (expr_type.IsSubclassOf (TypeManager.enum_type)))){
 259
 260                                         result = null;
 261                                         if (Convert.ImplicitConversionExists (ec, e, TypeManager.int32_type)){
 262                                                 result = new Cast (new TypeExpression (TypeManager.int32_type, loc), e, loc);
 263                                                 result = result.Resolve (ec);
 264                                         } else if (Convert.ImplicitConversionExists (ec, e, TypeManager.uint32_type)){
 265                                                 result = new Cast (new TypeExpression (TypeManager.uint32_type, loc), e, loc);
 266                                                 result = result.Resolve (ec);
 267                                         } else if (Convert.ImplicitConversionExists (ec, e, TypeManager.int64_type)){
 268                                                 result = new Cast (new TypeExpression (TypeManager.int64_type, loc), e, loc);
 269                                                 result = result.Resolve (ec);
 270                                         } else if (Convert.ImplicitConversionExists (ec, e, TypeManager.uint64_type)){
 271                                                 result = new Cast (new TypeExpression (TypeManager.uint64_type, loc), e, loc);
 272                                                 result = result.Resolve (ec);
 273                                         }
 274
 275                                         if (result == null || !(result is Constant)){
 276                                                 result = null;
 277                                                 Error23 (expr_type);
 278                                                 return false;
 279                                         }
 280
 281                                         expr_type = result.Type;
 282                                         e = (Constant) result;
 283                                 }
 284
 285                                 if (e is EnumConstant){
 286                                         EnumConstant enum_constant = (EnumConstant) e;
 287                                         Expression reduced;
 288
 289                                         if (Reduce (ec, enum_constant.Child, out reduced)){
 290                                                 result = new EnumConstant ((Constant) reduced, enum_constant.Type);
 291                                                 return true;
 292                                         } else {
 293                                                 result = null;
 294                                                 return false;
 295                                         }
 296                                 }
 297
 298                                 if (expr_type == TypeManager.int32_type){
 299                                         result = new IntConstant (~ ((IntConstant) e).Value);
 300                                 } else if (expr_type == TypeManager.uint32_type){
 301                                         result = new UIntConstant (~ ((UIntConstant) e).Value);
 302                                 } else if (expr_type == TypeManager.int64_type){
 303                                         result = new LongConstant (~ ((LongConstant) e).Value);
 304                                 } else if (expr_type == TypeManager.uint64_type){
 305                                         result = new ULongConstant (~ ((ULongConstant) e).Value);
 306                                 } else {
 307                                         result = null;
 308                                         Error23 (expr_type);
 309                                         return false;
 310                                 }
 311                                 return true;
 312
 313                         case Operator.AddressOf:
 314                                 result = this;
 315                                 return false;
 316
 317                         case Operator.Indirection:
 318                                 result = this;
 319                                 return false;
 320                         }
 321                         throw new Exception ("Can not constant fold: " + Oper.ToString());
 322                 }
 323
 324                 Expression ResolveOperator (EmitContext ec)
 325                 {
 326                         Type expr_type = Expr.Type;
 327
 328                         //
 329                         // Step 1: Perform Operator Overload location
 330                         //
 331                         Expression mg;
 332                         string op_name;
 333
 334                         op_name = oper_names [(int) Oper];
 335
 336                         mg = MemberLookup (ec, expr_type, op_name, MemberTypes.Method, AllBindingFlags, loc);
 337
 338                         if (mg != null) {
 339                                 Expression e = StaticCallExpr.MakeSimpleCall (
 340                                         ec, (MethodGroupExpr) mg, Expr, loc);
 341
 342                                 if (e == null){
 343                                         Error23 (expr_type);
 344                                         return null;
 345                                 }
 346
 347                                 return e;
 348                         }
 349
 350                         // Only perform numeric promotions on:
 351                         // +, -
 352
 353                         if (expr_type == null)
 354                                 return null;
 355
 356                         //
 357                         // Step 2: Default operations on CLI native types.
 358                         //
 359
 360                         // Attempt to use a constant folding operation.
 361                         if (Expr is Constant){
 362                                 Expression result;
 363
 364                                 if (Reduce (ec, (Constant) Expr, out result))
 365                                         return result;
 366                         }
 367
 368                         switch (Oper){
 369                         case Operator.LogicalNot:
 370                                 if (expr_type != TypeManager.bool_type) {
 371                                         Expr = ResolveBoolean (ec, Expr, loc);
 372                                         if (Expr == null){
 373                                                 Error23 (expr_type);
 374                                                 return null;
 375                                         }
 376                                 }
 377
 378                                 type = TypeManager.bool_type;
 379                                 return this;
 380
 381                         case Operator.OnesComplement:
 382                                 if (!((expr_type == TypeManager.int32_type) ||
 383                                       (expr_type == TypeManager.uint32_type) ||
 384                                       (expr_type == TypeManager.int64_type) ||
 385                                       (expr_type == TypeManager.uint64_type) ||
 386                                       (expr_type.IsSubclassOf (TypeManager.enum_type)))){
 387                                         Expression e;
 388
 389                                         e = Convert.ImplicitConversion (ec, Expr, TypeManager.int32_type, loc);
 390                                         if (e != null){
 391                                                 type = TypeManager.int32_type;
 392                                                 return this;
 393                                         }
 394                                         e = Convert.ImplicitConversion (ec, Expr, TypeManager.uint32_type, loc);
 395                                         if (e != null){
 396                                                 type = TypeManager.uint32_type;
 397                                                 return this;
 398                                         }
 399                                         e = Convert.ImplicitConversion (ec, Expr, TypeManager.int64_type, loc);
 400                                         if (e != null){
 401                                                 type = TypeManager.int64_type;
 402                                                 return this;
 403                                         }
 404                                         e = Convert.ImplicitConversion (ec, Expr, TypeManager.uint64_type, loc);
 405                                         if (e != null){
 406                                                 type = TypeManager.uint64_type;
 407                                                 return this;
 408                                         }
 409                                         Error23 (expr_type);
 410                                         return null;
 411                                 }
 412                                 type = expr_type;
 413                                 return this;
 414
 415                         case Operator.AddressOf:
 416                                 if (Expr.eclass != ExprClass.Variable){
 417                                         Error (211, "Cannot take the address of non-variables");
 418                                         return null;
 419                                 }
 420
 421                                 if (!ec.InUnsafe) {
 422                                         UnsafeError (loc);
 423                                         return null;
 424                                 }
 425
 426                                 if (!TypeManager.VerifyUnManaged (Expr.Type, loc)){
 427                                         return null;
 428                                 }
 429
 430                                 IVariable variable = Expr as IVariable;
 431                                 if (!ec.InFixedInitializer && ((variable == null) || !variable.VerifyFixed (false))) {
 432                                         Error (212, "You can only take the address of an unfixed expression inside " +
 433                                                "of a fixed statement initializer");
 434                                         return null;
 435                                 }
 436
 437                                 if (ec.InFixedInitializer && ((variable != null) && variable.VerifyFixed (false))) {
 438                                         Error (213, "You can not fix an already fixed expression");
 439                                         return null;
 440                                 }
 441
 442                                 // According to the specs, a variable is considered definitely assigned if you take
 443                                 // its address.
 444                                 if ((variable != null) && (variable.VariableInfo != null))
 445                                         variable.VariableInfo.SetAssigned (ec);
 446
 447                                 type = TypeManager.GetPointerType (Expr.Type);
 448                                 return this;
 449
 450                         case Operator.Indirection:
 451                                 if (!ec.InUnsafe){
 452                                         UnsafeError (loc);
 453                                         return null;
 454                                 }
 455
 456                                 if (!expr_type.IsPointer){
 457                                         Error (193, "The * or -> operator can only be applied to pointers");
 458                                         return null;
 459                                 }
 460
 461                                 //
 462                                 // We create an Indirection expression, because
 463                                 // it can implement the IMemoryLocation.
 464                                 //
 465                                 return new Indirection (Expr, loc);
 466
 467                         case Operator.UnaryPlus:
 468                                 //
 469                                 // A plus in front of something is just a no-op, so return the child.
 470                                 //
 471                                 return Expr;
 472
 473                         case Operator.UnaryNegation:
 474                                 //
 475                                 // Deals with -literals
 476                                 // int     operator- (int x)
 477                                 // long    operator- (long x)
 478                                 // float   operator- (float f)
 479                                 // double  operator- (double d)
 480                                 // decimal operator- (decimal d)
 481                                 //
 482                                 Expression expr = null;
 483
 484                                 //
 485                                 // transform - - expr into expr
 486                                 //
 487                                 if (Expr is Unary){
 488                                         Unary unary = (Unary) Expr;
 489
 490                                         if (unary.Oper == Operator.UnaryNegation)
 491                                                 return unary.Expr;
 492                                 }
 493
 494                                 //
 495                                 // perform numeric promotions to int,
 496                                 // long, double.
 497                                 //
 498                                 //
 499                                 // The following is inneficient, because we call
 500                                 // ImplicitConversion too many times.
 501                                 //
 502                                 // It is also not clear if we should convert to Float
 503                                 // or Double initially.
 504                                 //
 505                                 if (expr_type == TypeManager.uint32_type){
 506                                         //
 507                                         // FIXME: handle exception to this rule that
 508                                         // permits the int value -2147483648 (-2^31) to
 509                                         // bt wrote as a decimal interger literal
 510                                         //
 511                                         type = TypeManager.int64_type;
 512                                         Expr = Convert.ImplicitConversion (ec, Expr, type, loc);
 513                                         return this;
 514                                 }
 515
 516                                 if (expr_type == TypeManager.uint64_type){
 517                                         //
 518                                         // FIXME: Handle exception of `long value'
 519                                         // -92233720368547758087 (-2^63) to be wrote as
 520                                         // decimal integer literal.
 521                                         //
 522                                         Error23 (expr_type);
 523                                         return null;
 524                                 }
 525
 526                                 if (expr_type == TypeManager.float_type){
 527                                         type = expr_type;
 528                                         return this;
 529                                 }
 530
 531                                 expr = Convert.ImplicitConversion (ec, Expr, TypeManager.int32_type, loc);
 532                                 if (expr != null){
 533                                         Expr = expr;
 534                                         type = expr.Type;
 535                                         return this;
 536                                 }
 537
 538                                 expr = Convert.ImplicitConversion (ec, Expr, TypeManager.int64_type, loc);
 539                                 if (expr != null){
 540                                         Expr = expr;
 541                                         type = expr.Type;
 542                                         return this;
 543                                 }
 544
 545                                 expr = Convert.ImplicitConversion (ec, Expr, TypeManager.double_type, loc);
 546                                 if (expr != null){
 547                                         Expr = expr;
 548                                         type = expr.Type;
 549                                         return this;
 550                                 }
 551
 552                                 Error23 (expr_type);
 553                                 return null;
 554                         }
 555
 556                         Error (187, "No such operator '" + OperName (Oper) + "' defined for type '" +
 557                                TypeManager.CSharpName (expr_type) + "'");
 558                         return null;
 559                 }
 560
 561                 public override Expression DoResolve (EmitContext ec)
 562                 {
 563                         if (Oper == Operator.AddressOf)
 564                                 Expr = Expr.ResolveLValue (ec, new EmptyExpression ());
 565                         else
 566                                 Expr = Expr.Resolve (ec);
 567
 568                         if (Expr == null)
 569                                 return null;
 570
 571                         eclass = ExprClass.Value;
 572                         return ResolveOperator (ec);
 573                 }
 574
 575                 public override Expression DoResolveLValue (EmitContext ec, Expression right)
 576                 {
 577                         if (Oper == Operator.Indirection)
 578                                 return base.DoResolveLValue (ec, right);
 579
 580                         Error (131, "The left-hand side of an assignment must be a " +
 581                                "variable, property or indexer");
 582                         return null;
 583                 }
 584
 585                 public override void Emit (EmitContext ec)
 586                 {
 587                         ILGenerator ig = ec.ig;
 588
 589                         switch (Oper) {
 590                         case Operator.UnaryPlus:
 591                                 throw new Exception ("This should be caught by Resolve");
 592
 593                         case Operator.UnaryNegation:
 594                                 if (ec.CheckState) {
 595                                         ig.Emit (OpCodes.Ldc_I4_0);
 596                                         if (type == TypeManager.int64_type)
 597                                                 ig.Emit (OpCodes.Conv_U8);
 598                                         Expr.Emit (ec);
 599                                         ig.Emit (OpCodes.Sub_Ovf);
 600                                 } else {
 601                                         Expr.Emit (ec);
 602                                         ig.Emit (OpCodes.Neg);
 603                                 }
 604
 605                                 break;
 606
 607                         case Operator.LogicalNot:
 608                                 Expr.Emit (ec);
 609                                 ig.Emit (OpCodes.Ldc_I4_0);
 610                                 ig.Emit (OpCodes.Ceq);
 611                                 break;
 612
 613                         case Operator.OnesComplement:
 614                                 Expr.Emit (ec);
 615                                 ig.Emit (OpCodes.Not);
 616                                 break;
 617
 618                         case Operator.AddressOf:
 619                                 ((IMemoryLocation)Expr).AddressOf (ec, AddressOp.LoadStore);
 620                                 break;
 621
 622                         default:
 623                                 throw new Exception ("This should not happen: Operator = "
 624                                                      + Oper.ToString ());
 625                         }
 626                 }
 627
 628                 public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
 629                 {
 630                         if (Oper == Operator.LogicalNot)
 631                                 Expr.EmitBranchable (ec, target, !onTrue);
 632                         else
 633                                 base.EmitBranchable (ec, target, onTrue);
 634                 }
 635
 636                 public override string ToString ()
 637                 {
 638                         return "Unary (" + Oper + ", " + Expr + ")";
 639                 }
 640
 641         }
 642
 643         //
 644         // Unary operators are turned into Indirection expressions
 645         // after semantic analysis (this is so we can take the address
 646         // of an indirection).
 647         //
 648         public class Indirection : Expression, IMemoryLocation, IAssignMethod {
 649                 Expression expr;
 650                 LocalTemporary temporary;
 651                 bool prepared;
 652
 653                 public Indirection (Expression expr, Location l)
 654                 {
 655                         this.expr = expr;
 656                         this.type = TypeManager.GetElementType (expr.Type);
 657                         eclass = ExprClass.Variable;
 658                         loc = l;
 659                 }
 660
 661                 void LoadExprValue (EmitContext ec)
 662                 {
 663                 }
 664
 665                 public override void Emit (EmitContext ec)
 666                 {
 667                         if (!prepared)
 668                                 expr.Emit (ec);
 669
 670                         LoadFromPtr (ec.ig, Type);
 671                 }
 672
 673                 public void Emit (EmitContext ec, bool leave_copy)
 674                 {
 675                         Emit (ec);
 676                         if (leave_copy) {
 677                                 ec.ig.Emit (OpCodes.Dup);
 678                                 temporary = new LocalTemporary (ec, expr.Type);
 679                                 temporary.Store (ec);
 680                         }
 681                 }
 682
 683                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 684                 {
 685                         prepared = prepare_for_load;
 686
 687                         expr.Emit (ec);
 688
 689                         if (prepare_for_load)
 690                                 ec.ig.Emit (OpCodes.Dup);
 691
 692                         source.Emit (ec);
 693                         if (leave_copy) {
 694                                 ec.ig.Emit (OpCodes.Dup);
 695                                 temporary = new LocalTemporary (ec, expr.Type);
 696                                 temporary.Store (ec);
 697                         }
 698
 699                         StoreFromPtr (ec.ig, type);
 700
 701                         if (temporary != null)
 702                                 temporary.Emit (ec);
 703                 }
 704
 705                 public void AddressOf (EmitContext ec, AddressOp Mode)
 706                 {
 707                         expr.Emit (ec);
 708                 }
 709
 710                 public override Expression DoResolve (EmitContext ec)
 711                 {
 712                         //
 713                         // Born fully resolved
 714                         //
 715                         return this;
 716                 }
 717
 718                 public override string ToString ()
 719                 {
 720                         return "*(" + expr + ")";
 721                 }
 722         }
 723
 724         /// <summary>
 725         ///   Unary Mutator expressions (pre and post ++ and --)
 726         /// </summary>
 727         ///
 728         /// <remarks>
 729         ///   UnaryMutator implements ++ and -- expressions.   It derives from
 730         ///   ExpressionStatement becuase the pre/post increment/decrement
 731         ///   operators can be used in a statement context.
 732         ///
 733         /// FIXME: Idea, we could split this up in two classes, one simpler
 734         /// for the common case, and one with the extra fields for more complex
 735         /// classes (indexers require temporary access;  overloaded require method)
 736         ///
 737         /// </remarks>
 738         public class UnaryMutator : ExpressionStatement {
 739                 [Flags]
 740                 public enum Mode : byte {
 741                         IsIncrement    = 0,
 742                         IsDecrement    = 1,
 743                         IsPre          = 0,
 744                         IsPost         = 2,
 745
 746                         PreIncrement   = 0,
 747                         PreDecrement   = IsDecrement,
 748                         PostIncrement  = IsPost,
 749                         PostDecrement  = IsPost | IsDecrement
 750                 }
 751
 752                 Mode mode;
 753                 bool is_expr = false;
 754                 bool recurse = false;
 755
 756                 Expression expr;
 757
 758                 //
 759                 // This is expensive for the simplest case.
 760                 //
 761                 StaticCallExpr method;
 762
 763                 public UnaryMutator (Mode m, Expression e, Location l)
 764                 {
 765                         mode = m;
 766                         loc = l;
 767                         expr = e;
 768                 }
 769
 770                 static string OperName (Mode mode)
 771                 {
 772                         return (mode == Mode.PreIncrement || mode == Mode.PostIncrement) ?
 773                                 "++" : "--";
 774                 }
 775
 776                 void Error23 (Type t)
 777                 {
 778                         Error (
 779                                 23, "Operator " + OperName (mode) +
 780                                 " cannot be applied to operand of type `" +
 781                                 TypeManager.CSharpName (t) + "'");
 782                 }
 783
 784                 /// <summary>
 785                 ///   Returns whether an object of type `t' can be incremented
 786                 ///   or decremented with add/sub (ie, basically whether we can
 787                 ///   use pre-post incr-decr operations on it, but it is not a
 788                 ///   System.Decimal, which we require operator overloading to catch)
 789                 /// </summary>
 790                 static bool IsIncrementableNumber (Type t)
 791                 {
 792                         return (t == TypeManager.sbyte_type) ||
 793                                 (t == TypeManager.byte_type) ||
 794                                 (t == TypeManager.short_type) ||
 795                                 (t == TypeManager.ushort_type) ||
 796                                 (t == TypeManager.int32_type) ||
 797                                 (t == TypeManager.uint32_type) ||
 798                                 (t == TypeManager.int64_type) ||
 799                                 (t == TypeManager.uint64_type) ||
 800                                 (t == TypeManager.char_type) ||
 801                                 (t.IsSubclassOf (TypeManager.enum_type)) ||
 802                                 (t == TypeManager.float_type) ||
 803                                 (t == TypeManager.double_type) ||
 804                                 (t.IsPointer && t != TypeManager.void_ptr_type);
 805                 }
 806
 807                 Expression ResolveOperator (EmitContext ec)
 808                 {
 809                         Type expr_type = expr.Type;
 810
 811                         //
 812                         // Step 1: Perform Operator Overload location
 813                         //
 814                         Expression mg;
 815                         string op_name;
 816
 817                         if (mode == Mode.PreIncrement || mode == Mode.PostIncrement)
 818                                 op_name = "op_Increment";
 819                         else
 820                                 op_name = "op_Decrement";
 821
 822                         mg = MemberLookup (ec, expr_type, op_name, MemberTypes.Method, AllBindingFlags, loc);
 823
 824                         if (mg == null && expr_type.BaseType != null)
 825                                 mg = MemberLookup (ec, expr_type.BaseType, op_name,
 826                                                    MemberTypes.Method, AllBindingFlags, loc);
 827
 828                         if (mg != null) {
 829                                 method = StaticCallExpr.MakeSimpleCall (
 830                                         ec, (MethodGroupExpr) mg, expr, loc);
 831
 832                                 type = method.Type;
 833                                 return this;
 834                         }
 835
 836                         //
 837                         // The operand of the prefix/postfix increment decrement operators
 838                         // should be an expression that is classified as a variable,
 839                         // a property access or an indexer access
 840                         //
 841                         type = expr_type;
 842                         if (expr.eclass == ExprClass.Variable){
 843                                 LocalVariableReference var = expr as LocalVariableReference;
 844                                 if ((var != null) && var.IsReadOnly)
 845                                         Error (1604, "cannot assign to `" + var.Name + "' because it is readonly");
 846                                 if (IsIncrementableNumber (expr_type) ||
 847                                     expr_type == TypeManager.decimal_type){
 848                                         return this;
 849                                 }
 850                         } else if (expr.eclass == ExprClass.IndexerAccess){
 851                                 IndexerAccess ia = (IndexerAccess) expr;
 852
 853                                 expr = ia.ResolveLValue (ec, this);
 854                                 if (expr == null)
 855                                         return null;
 856
 857                                 return this;
 858                         } else if (expr.eclass == ExprClass.PropertyAccess){
 859                                 PropertyExpr pe = (PropertyExpr) expr;
 860
 861                                 if (pe.VerifyAssignable ())
 862                                         return this;
 863
 864                                 return null;
 865                         } else {
 866                                 expr.Error_UnexpectedKind ("variable, indexer or property access");
 867                                 return null;
 868                         }
 869
 870                         Error (187, "No such operator '" + OperName (mode) + "' defined for type '" +
 871                                TypeManager.CSharpName (expr_type) + "'");
 872                         return null;
 873                 }
 874
 875                 public override Expression DoResolve (EmitContext ec)
 876                 {
 877                         expr = expr.Resolve (ec);
 878
 879                         if (expr == null)
 880                                 return null;
 881
 882                         eclass = ExprClass.Value;
 883                         return ResolveOperator (ec);
 884                 }
 885
 886                 static int PtrTypeSize (Type t)
 887                 {
 888                         return GetTypeSize (TypeManager.GetElementType (t));
 889                 }
 890
 891                 //
 892                 // Loads the proper "1" into the stack based on the type, then it emits the
 893                 // opcode for the operation requested
 894                 //
 895                 void LoadOneAndEmitOp (EmitContext ec, Type t)
 896                 {
 897                         //
 898                         // Measure if getting the typecode and using that is more/less efficient
 899                         // that comparing types.  t.GetTypeCode() is an internal call.
 900                         //
 901                         ILGenerator ig = ec.ig;
 902
 903                         if (t == TypeManager.uint64_type || t == TypeManager.int64_type)
 904                                 LongConstant.EmitLong (ig, 1);
 905                         else if (t == TypeManager.double_type)
 906                                 ig.Emit (OpCodes.Ldc_R8, 1.0);
 907                         else if (t == TypeManager.float_type)
 908                                 ig.Emit (OpCodes.Ldc_R4, 1.0F);
 909                         else if (t.IsPointer){
 910                                 int n = PtrTypeSize (t);
 911
 912                                 if (n == 0)
 913                                         ig.Emit (OpCodes.Sizeof, t);
 914                                 else
 915                                         IntConstant.EmitInt (ig, n);
 916                         } else
 917                                 ig.Emit (OpCodes.Ldc_I4_1);
 918
 919                         //
 920                         // Now emit the operation
 921                         //
 922                         if (ec.CheckState){
 923                                 if (t == TypeManager.int32_type ||
 924                                     t == TypeManager.int64_type){
 925                                         if ((mode & Mode.IsDecrement) != 0)
 926                                                 ig.Emit (OpCodes.Sub_Ovf);
 927                                         else
 928                                                 ig.Emit (OpCodes.Add_Ovf);
 929                                 } else if (t == TypeManager.uint32_type ||
 930                                            t == TypeManager.uint64_type){
 931                                         if ((mode & Mode.IsDecrement) != 0)
 932                                                 ig.Emit (OpCodes.Sub_Ovf_Un);
 933                                         else
 934                                                 ig.Emit (OpCodes.Add_Ovf_Un);
 935                                 } else {
 936                                         if ((mode & Mode.IsDecrement) != 0)
 937                                                 ig.Emit (OpCodes.Sub_Ovf);
 938                                         else
 939                                                 ig.Emit (OpCodes.Add_Ovf);
 940                                 }
 941                         } else {
 942                                 if ((mode & Mode.IsDecrement) != 0)
 943                                         ig.Emit (OpCodes.Sub);
 944                                 else
 945                                         ig.Emit (OpCodes.Add);
 946                         }
 947
 948                         if (t == TypeManager.sbyte_type){
 949                                 if (ec.CheckState)
 950                                         ig.Emit (OpCodes.Conv_Ovf_I1);
 951                                 else
 952                                         ig.Emit (OpCodes.Conv_I1);
 953                         } else if (t == TypeManager.byte_type){
 954                                 if (ec.CheckState)
 955                                         ig.Emit (OpCodes.Conv_Ovf_U1);
 956                                 else
 957                                         ig.Emit (OpCodes.Conv_U1);
 958                         } else if (t == TypeManager.short_type){
 959                                 if (ec.CheckState)
 960                                         ig.Emit (OpCodes.Conv_Ovf_I2);
 961                                 else
 962                                         ig.Emit (OpCodes.Conv_I2);
 963                         } else if (t == TypeManager.ushort_type || t == TypeManager.char_type){
 964                                 if (ec.CheckState)
 965                                         ig.Emit (OpCodes.Conv_Ovf_U2);
 966                                 else
 967                                         ig.Emit (OpCodes.Conv_U2);
 968                         }
 969
 970                 }
 971
 972                 void EmitCode (EmitContext ec, bool is_expr)
 973                 {
 974                         recurse = true;
 975                         this.is_expr = is_expr;
 976                         ((IAssignMethod) expr).EmitAssign (ec, this, is_expr && (mode == Mode.PreIncrement || mode == Mode.PreDecrement), true);
 977                 }
 978
 979
 980                 public override void Emit (EmitContext ec)
 981                 {
 982                         //
 983                         // We use recurse to allow ourselfs to be the source
 984                         // of an assignment. This little hack prevents us from
 985                         // having to allocate another expression
 986                         //
 987                         if (recurse) {
 988                                 ((IAssignMethod) expr).Emit (ec, is_expr && (mode == Mode.PostIncrement  || mode == Mode.PostDecrement));
 989                                 if (method == null)
 990                                         LoadOneAndEmitOp (ec, expr.Type);
 991                                 else
 992                                         ec.ig.Emit (OpCodes.Call, method.Method);
 993                                 recurse = false;
 994                                 return;
 995                         }
 996
 997                         EmitCode (ec, true);
 998                 }
 999
1000                 public override void EmitStatement (EmitContext ec)
1001                 {
1002                         EmitCode (ec, false);
1003                 }
1004         }
1005
1006         /// <summary>
1007         ///   Base class for the `Is' and `As' classes.
1008         /// </summary>
1009         ///
1010         /// <remarks>
1011         ///   FIXME: Split this in two, and we get to save the `Operator' Oper
1012         ///   size.
1013         /// </remarks>
1014         public abstract class Probe : Expression {
1015                 public readonly Expression ProbeType;
1016                 protected Expression expr;
1017                 protected Type probe_type;
1018
1019                 public Probe (Expression expr, Expression probe_type, Location l)
1020                 {
1021                         ProbeType = probe_type;
1022                         loc = l;
1023                         this.expr = expr;
1024                 }
1025
1026                 public Expression Expr {
1027                         get {
1028                                 return expr;
1029                         }
1030                 }
1031
1032                 public override Expression DoResolve (EmitContext ec)
1033                 {
1034                         probe_type = ec.DeclSpace.ResolveType (ProbeType, false, loc);
1035
1036                         if (probe_type == null)
1037                                 return null;
1038
1039                         CheckObsoleteAttribute (probe_type);
1040
1041                         expr = expr.Resolve (ec);
1042                         if (expr == null)
1043                                 return null;
1044
1045                         if (expr.Type.IsPointer) {
1046                                 Report.Error (244, loc, "\"is\" or \"as\" are not valid on pointer types");
1047                                 return null;
1048                         }
1049                         return this;
1050                 }
1051         }
1052
1053         /// <summary>
1054         ///   Implementation of the `is' operator.
1055         /// </summary>
1056         public class Is : Probe {
1057                 public Is (Expression expr, Expression probe_type, Location l)
1058                         : base (expr, probe_type, l)
1059                 {
1060                 }
1061
1062                 enum Action {
1063                         AlwaysTrue, AlwaysNull, AlwaysFalse, LeaveOnStack, Probe
1064                 }
1065
1066                 Action action;
1067
1068                 public override void Emit (EmitContext ec)
1069                 {
1070                         ILGenerator ig = ec.ig;
1071
1072                         expr.Emit (ec);
1073
1074                         switch (action){
1075                         case Action.AlwaysFalse:
1076                                 ig.Emit (OpCodes.Pop);
1077                                 IntConstant.EmitInt (ig, 0);
1078                                 return;
1079                         case Action.AlwaysTrue:
1080                                 ig.Emit (OpCodes.Pop);
1081                                 IntConstant.EmitInt (ig, 1);
1082                                 return;
1083                         case Action.LeaveOnStack:
1084                                 // the `e != null' rule.
1085                                 ig.Emit (OpCodes.Ldnull);
1086                                 ig.Emit (OpCodes.Ceq);
1087                                 ig.Emit (OpCodes.Ldc_I4_0);
1088                                 ig.Emit (OpCodes.Ceq);
1089                                 return;
1090                         case Action.Probe:
1091                                 ig.Emit (OpCodes.Isinst, probe_type);
1092                                 ig.Emit (OpCodes.Ldnull);
1093                                 ig.Emit (OpCodes.Cgt_Un);
1094                                 return;
1095                         }
1096                         throw new Exception ("never reached");
1097                 }
1098
1099                 public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
1100                 {
1101                         ILGenerator ig = ec.ig;
1102
1103                         switch (action){
1104                         case Action.AlwaysFalse:
1105                                 if (! onTrue)
1106                                         ig.Emit (OpCodes.Br, target);
1107
1108                                 return;
1109                         case Action.AlwaysTrue:
1110                                 if (onTrue)
1111                                         ig.Emit (OpCodes.Br, target);
1112
1113                                 return;
1114                         case Action.LeaveOnStack:
1115                                 // the `e != null' rule.
1116                                 expr.Emit (ec);
1117                                 ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
1118                                 return;
1119                         case Action.Probe:
1120                                 expr.Emit (ec);
1121                                 ig.Emit (OpCodes.Isinst, probe_type);
1122                                 ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
1123                                 return;
1124                         }
1125                         throw new Exception ("never reached");
1126                 }
1127
1128                 public override Expression DoResolve (EmitContext ec)
1129                 {
1130                         Expression e = base.DoResolve (ec);
1131
1132                         if ((e == null) || (expr == null))
1133                                 return null;
1134
1135                         Type etype = expr.Type;
1136                         bool warning_always_matches = false;
1137                         bool warning_never_matches = false;
1138
1139                         type = TypeManager.bool_type;
1140                         eclass = ExprClass.Value;
1141
1142                         //
1143                         // First case, if at compile time, there is an implicit conversion
1144                         // then e != null (objects) or true (value types)
1145                         //
1146                         e = Convert.ImplicitConversionStandard (ec, expr, probe_type, loc);
1147                         if (e != null){
1148                                 expr = e;
1149                                 if (etype.IsValueType)
1150                                         action = Action.AlwaysTrue;
1151                                 else
1152                                         action = Action.LeaveOnStack;
1153
1154                                 warning_always_matches = true;
1155                         } else if (Convert.ExplicitReferenceConversionExists (etype, probe_type)){
1156                                 //
1157                                 // Second case: explicit reference convresion
1158                                 //
1159                                 if (expr is NullLiteral)
1160                                         action = Action.AlwaysFalse;
1161                                 else
1162                                         action = Action.Probe;
1163                         } else {
1164                                 action = Action.AlwaysFalse;
1165                                 warning_never_matches = true;
1166                         }
1167
1168                         if (warning_always_matches)
1169                                 Warning (183, "The given expression is always of the provided ('{0}') type", TypeManager.CSharpName (probe_type));
1170                         else if (warning_never_matches){
1171                                 if (!(probe_type.IsInterface || expr.Type.IsInterface))
1172                                         Warning (184, "The given expression is never of the provided ('{0}') type", TypeManager.CSharpName (probe_type));
1173                         }
1174
1175                         return this;
1176                 }
1177         }
1178
1179         /// <summary>
1180         ///   Implementation of the `as' operator.
1181         /// </summary>
1182         public class As : Probe {
1183                 public As (Expression expr, Expression probe_type, Location l)
1184                         : base (expr, probe_type, l)
1185                 {
1186                 }
1187
1188                 bool do_isinst = false;
1189
1190                 public override void Emit (EmitContext ec)
1191                 {
1192                         ILGenerator ig = ec.ig;
1193
1194                         expr.Emit (ec);
1195
1196                         if (do_isinst)
1197                                 ig.Emit (OpCodes.Isinst, probe_type);
1198                 }
1199
1200                 static void Error_CannotConvertType (Type source, Type target, Location loc)
1201                 {
1202                         Report.Error (
1203                                 39, loc, "as operator can not convert from `" +
1204                                 TypeManager.CSharpName (source) + "' to `" +
1205                                 TypeManager.CSharpName (target) + "'");
1206                 }
1207
1208                 public override Expression DoResolve (EmitContext ec)
1209                 {
1210                         Expression e = base.DoResolve (ec);
1211
1212                         if (e == null)
1213                                 return null;
1214
1215                         type = probe_type;
1216                         eclass = ExprClass.Value;
1217                         Type etype = expr.Type;
1218
1219                         if (TypeManager.IsValueType (probe_type)){
1220                                 Report.Error (77, loc, "The as operator should be used with a reference type only (" +
1221                                               TypeManager.CSharpName (probe_type) + " is a value type)");
1222                                 return null;
1223
1224                         }
1225
1226                         e = Convert.ImplicitConversion (ec, expr, probe_type, loc);
1227                         if (e != null){
1228                                 expr = e;
1229                                 do_isinst = false;
1230                                 return this;
1231                         }
1232
1233                         if (Convert.ExplicitReferenceConversionExists (etype, probe_type)){
1234                                 do_isinst = true;
1235                                 return this;
1236                         }
1237
1238                         Error_CannotConvertType (etype, probe_type, loc);
1239                         return null;
1240                 }
1241         }
1242
1243         /// <summary>
1244         ///   This represents a typecast in the source language.
1245         ///
1246         ///   FIXME: Cast expressions have an unusual set of parsing
1247         ///   rules, we need to figure those out.
1248         /// </summary>
1249         public class Cast : Expression {
1250                 Expression target_type;
1251                 Expression expr;
1252
1253                 public Cast (Expression cast_type, Expression expr, Location loc)
1254                 {
1255                         this.target_type = cast_type;
1256                         this.expr = expr;
1257                         this.loc = loc;
1258                 }
1259
1260                 public Expression TargetType {
1261                         get {
1262                                 return target_type;
1263                         }
1264                 }
1265
1266                 public Expression Expr {
1267                         get {
1268                                 return expr;
1269                         }
1270                         set {
1271                                 expr = value;
1272                         }
1273                 }
1274
1275                 bool CheckRange (EmitContext ec, long value, Type type, long min, long max)
1276                 {
1277                         if (!ec.ConstantCheckState)
1278                                 return true;
1279
1280                         if ((value < min) || (value > max)) {
1281                                 Error (221, "Constant value `" + value + "' cannot be converted " +
1282                                        "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
1283                                        "syntax to override)");
1284                                 return false;
1285                         }
1286
1287                         return true;
1288                 }
1289
1290                 bool CheckRange (EmitContext ec, ulong value, Type type, ulong max)
1291                 {
1292                         if (!ec.ConstantCheckState)
1293                                 return true;
1294
1295                         if (value > max) {
1296                                 Error (221, "Constant value `" + value + "' cannot be converted " +
1297                                        "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
1298                                        "syntax to override)");
1299                                 return false;
1300                         }
1301
1302                         return true;
1303                 }
1304
1305                 bool CheckUnsigned (EmitContext ec, long value, Type type)
1306                 {
1307                         if (!ec.ConstantCheckState)
1308                                 return true;
1309
1310                         if (value < 0) {
1311                                 Error (221, "Constant value `" + value + "' cannot be converted " +
1312                                        "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
1313                                        "syntax to override)");
1314                                 return false;
1315                         }
1316
1317                         return true;
1318                 }
1319
1320                 /// <summary>
1321                 ///   Attempts to do a compile-time folding of a constant cast.
1322                 /// </summary>
1323                 Expression TryReduce (EmitContext ec, Type target_type)
1324                 {
1325                         Expression real_expr = expr;
1326                         if (real_expr is EnumConstant)
1327                                 real_expr = ((EnumConstant) real_expr).Child;
1328
1329                         if (real_expr is ByteConstant){
1330                                 byte v = ((ByteConstant) real_expr).Value;
1331
1332                                 if (target_type == TypeManager.sbyte_type) {
1333                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1334                                                 return null;
1335                                         return new SByteConstant ((sbyte) v);
1336                                 }
1337                                 if (target_type == TypeManager.short_type)
1338                                         return new ShortConstant ((short) v);
1339                                 if (target_type == TypeManager.ushort_type)
1340                                         return new UShortConstant ((ushort) v);
1341                                 if (target_type == TypeManager.int32_type)
1342                                         return new IntConstant ((int) v);
1343                                 if (target_type == TypeManager.uint32_type)
1344                                         return new UIntConstant ((uint) v);
1345                                 if (target_type == TypeManager.int64_type)
1346                                         return new LongConstant ((long) v);
1347                                 if (target_type == TypeManager.uint64_type)
1348                                         return new ULongConstant ((ulong) v);
1349                                 if (target_type == TypeManager.float_type)
1350                                         return new FloatConstant ((float) v);
1351                                 if (target_type == TypeManager.double_type)
1352                                         return new DoubleConstant ((double) v);
1353                                 if (target_type == TypeManager.char_type)
1354                                         return new CharConstant ((char) v);
1355                                 if (target_type == TypeManager.decimal_type)
1356                                         return new DecimalConstant ((decimal) v);
1357                         }
1358                         if (real_expr is SByteConstant){
1359                                 sbyte v = ((SByteConstant) real_expr).Value;
1360
1361                                 if (target_type == TypeManager.byte_type) {
1362                                         if (!CheckUnsigned (ec, v, target_type))
1363                                                 return null;
1364                                         return new ByteConstant ((byte) v);
1365                                 }
1366                                 if (target_type == TypeManager.short_type)
1367                                         return new ShortConstant ((short) v);
1368                                 if (target_type == TypeManager.ushort_type) {
1369                                         if (!CheckUnsigned (ec, v, target_type))
1370                                                 return null;
1371                                         return new UShortConstant ((ushort) v);
1372                                 } if (target_type == TypeManager.int32_type)
1373                                         return new IntConstant ((int) v);
1374                                 if (target_type == TypeManager.uint32_type) {
1375                                         if (!CheckUnsigned (ec, v, target_type))
1376                                                 return null;
1377                                         return new UIntConstant ((uint) v);
1378                                 } if (target_type == TypeManager.int64_type)
1379                                         return new LongConstant ((long) v);
1380                                 if (target_type == TypeManager.uint64_type) {
1381                                         if (!CheckUnsigned (ec, v, target_type))
1382                                                 return null;
1383                                         return new ULongConstant ((ulong) v);
1384                                 }
1385                                 if (target_type == TypeManager.float_type)
1386                                         return new FloatConstant ((float) v);
1387                                 if (target_type == TypeManager.double_type)
1388                                         return new DoubleConstant ((double) v);
1389                                 if (target_type == TypeManager.char_type) {
1390                                         if (!CheckUnsigned (ec, v, target_type))
1391                                                 return null;
1392                                         return new CharConstant ((char) v);
1393                                 }
1394                                 if (target_type == TypeManager.decimal_type)
1395                                         return new DecimalConstant ((decimal) v);
1396                         }
1397                         if (real_expr is ShortConstant){
1398                                 short v = ((ShortConstant) real_expr).Value;
1399
1400                                 if (target_type == TypeManager.byte_type) {
1401                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1402                                                 return null;
1403                                         return new ByteConstant ((byte) v);
1404                                 }
1405                                 if (target_type == TypeManager.sbyte_type) {
1406                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1407                                                 return null;
1408                                         return new SByteConstant ((sbyte) v);
1409                                 }
1410                                 if (target_type == TypeManager.ushort_type) {
1411                                         if (!CheckUnsigned (ec, v, target_type))
1412                                                 return null;
1413                                         return new UShortConstant ((ushort) v);
1414                                 }
1415                                 if (target_type == TypeManager.int32_type)
1416                                         return new IntConstant ((int) v);
1417                                 if (target_type == TypeManager.uint32_type) {
1418                                         if (!CheckUnsigned (ec, v, target_type))
1419                                                 return null;
1420                                         return new UIntConstant ((uint) v);
1421                                 }
1422                                 if (target_type == TypeManager.int64_type)
1423                                         return new LongConstant ((long) v);
1424                                 if (target_type == TypeManager.uint64_type) {
1425                                         if (!CheckUnsigned (ec, v, target_type))
1426                                                 return null;
1427                                         return new ULongConstant ((ulong) v);
1428                                 }
1429                                 if (target_type == TypeManager.float_type)
1430                                         return new FloatConstant ((float) v);
1431                                 if (target_type == TypeManager.double_type)
1432                                         return new DoubleConstant ((double) v);
1433                                 if (target_type == TypeManager.char_type) {
1434                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1435                                                 return null;
1436                                         return new CharConstant ((char) v);
1437                                 }
1438                                 if (target_type == TypeManager.decimal_type)
1439                                         return new DecimalConstant ((decimal) v);
1440                         }
1441                         if (real_expr is UShortConstant){
1442                                 ushort v = ((UShortConstant) real_expr).Value;
1443
1444                                 if (target_type == TypeManager.byte_type) {
1445                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1446                                                 return null;
1447                                         return new ByteConstant ((byte) v);
1448                                 }
1449                                 if (target_type == TypeManager.sbyte_type) {
1450                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1451                                                 return null;
1452                                         return new SByteConstant ((sbyte) v);
1453                                 }
1454                                 if (target_type == TypeManager.short_type) {
1455                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1456                                                 return null;
1457                                         return new ShortConstant ((short) v);
1458                                 }
1459                                 if (target_type == TypeManager.int32_type)
1460                                         return new IntConstant ((int) v);
1461                                 if (target_type == TypeManager.uint32_type)
1462                                         return new UIntConstant ((uint) v);
1463                                 if (target_type == TypeManager.int64_type)
1464                                         return new LongConstant ((long) v);
1465                                 if (target_type == TypeManager.uint64_type)
1466                                         return new ULongConstant ((ulong) v);
1467                                 if (target_type == TypeManager.float_type)
1468                                         return new FloatConstant ((float) v);
1469                                 if (target_type == TypeManager.double_type)
1470                                         return new DoubleConstant ((double) v);
1471                                 if (target_type == TypeManager.char_type) {
1472                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1473                                                 return null;
1474                                         return new CharConstant ((char) v);
1475                                 }
1476                                 if (target_type == TypeManager.decimal_type)
1477                                         return new DecimalConstant ((decimal) v);
1478                         }
1479                         if (real_expr is IntConstant){
1480                                 int v = ((IntConstant) real_expr).Value;
1481
1482                                 if (target_type == TypeManager.byte_type) {
1483                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1484                                                 return null;
1485                                         return new ByteConstant ((byte) v);
1486                                 }
1487                                 if (target_type == TypeManager.sbyte_type) {
1488                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1489                                                 return null;
1490                                         return new SByteConstant ((sbyte) v);
1491                                 }
1492                                 if (target_type == TypeManager.short_type) {
1493                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1494                                                 return null;
1495                                         return new ShortConstant ((short) v);
1496                                 }
1497                                 if (target_type == TypeManager.ushort_type) {
1498                                         if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
1499                                                 return null;
1500                                         return new UShortConstant ((ushort) v);
1501                                 }
1502                                 if (target_type == TypeManager.uint32_type) {
1503                                         if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
1504                                                 return null;
1505                                         return new UIntConstant ((uint) v);
1506                                 }
1507                                 if (target_type == TypeManager.int64_type)
1508                                         return new LongConstant ((long) v);
1509                                 if (target_type == TypeManager.uint64_type) {
1510                                         if (!CheckUnsigned (ec, v, target_type))
1511                                                 return null;
1512                                         return new ULongConstant ((ulong) v);
1513                                 }
1514                                 if (target_type == TypeManager.float_type)
1515                                         return new FloatConstant ((float) v);
1516                                 if (target_type == TypeManager.double_type)
1517                                         return new DoubleConstant ((double) v);
1518                                 if (target_type == TypeManager.char_type) {
1519                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1520                                                 return null;
1521                                         return new CharConstant ((char) v);
1522                                 }
1523                                 if (target_type == TypeManager.decimal_type)
1524                                         return new DecimalConstant ((decimal) v);
1525                         }
1526                         if (real_expr is UIntConstant){
1527                                 uint v = ((UIntConstant) real_expr).Value;
1528
1529                                 if (target_type == TypeManager.byte_type) {
1530                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1531                                                 return null;
1532                                         return new ByteConstant ((byte) v);
1533                                 }
1534                                 if (target_type == TypeManager.sbyte_type) {
1535                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1536                                                 return null;
1537                                         return new SByteConstant ((sbyte) v);
1538                                 }
1539                                 if (target_type == TypeManager.short_type) {
1540                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1541                                                 return null;
1542                                         return new ShortConstant ((short) v);
1543                                 }
1544                                 if (target_type == TypeManager.ushort_type) {
1545                                         if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
1546                                                 return null;
1547                                         return new UShortConstant ((ushort) v);
1548                                 }
1549                                 if (target_type == TypeManager.int32_type) {
1550                                         if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
1551                                                 return null;
1552                                         return new IntConstant ((int) v);
1553                                 }
1554                                 if (target_type == TypeManager.int64_type)
1555                                         return new LongConstant ((long) v);
1556                                 if (target_type == TypeManager.uint64_type)
1557                                         return new ULongConstant ((ulong) v);
1558                                 if (target_type == TypeManager.float_type)
1559                                         return new FloatConstant ((float) v);
1560                                 if (target_type == TypeManager.double_type)
1561                                         return new DoubleConstant ((double) v);
1562                                 if (target_type == TypeManager.char_type) {
1563                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1564                                                 return null;
1565                                         return new CharConstant ((char) v);
1566                                 }
1567                                 if (target_type == TypeManager.decimal_type)
1568                                         return new DecimalConstant ((decimal) v);
1569                         }
1570                         if (real_expr is LongConstant){
1571                                 long v = ((LongConstant) real_expr).Value;
1572
1573                                 if (target_type == TypeManager.byte_type) {
1574                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1575                                                 return null;
1576                                         return new ByteConstant ((byte) v);
1577                                 }
1578                                 if (target_type == TypeManager.sbyte_type) {
1579                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1580                                                 return null;
1581                                         return new SByteConstant ((sbyte) v);
1582                                 }
1583                                 if (target_type == TypeManager.short_type) {
1584                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1585                                                 return null;
1586                                         return new ShortConstant ((short) v);
1587                                 }
1588                                 if (target_type == TypeManager.ushort_type) {
1589                                         if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
1590                                                 return null;
1591                                         return new UShortConstant ((ushort) v);
1592                                 }
1593                                 if (target_type == TypeManager.int32_type) {
1594                                         if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
1595                                                 return null;
1596                                         return new IntConstant ((int) v);
1597                                 }
1598                                 if (target_type == TypeManager.uint32_type) {
1599                                         if (!CheckRange (ec, v, target_type, UInt32.MinValue, UInt32.MaxValue))
1600                                                 return null;
1601                                         return new UIntConstant ((uint) v);
1602                                 }
1603                                 if (target_type == TypeManager.uint64_type) {
1604                                         if (!CheckUnsigned (ec, v, target_type))
1605                                                 return null;
1606                                         return new ULongConstant ((ulong) v);
1607                                 }
1608                                 if (target_type == TypeManager.float_type)
1609                                         return new FloatConstant ((float) v);
1610                                 if (target_type == TypeManager.double_type)
1611                                         return new DoubleConstant ((double) v);
1612                                 if (target_type == TypeManager.char_type) {
1613                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1614                                                 return null;
1615                                         return new CharConstant ((char) v);
1616                                 }
1617                                 if (target_type == TypeManager.decimal_type)
1618                                         return new DecimalConstant ((decimal) v);
1619                         }
1620                         if (real_expr is ULongConstant){
1621                                 ulong v = ((ULongConstant) real_expr).Value;
1622
1623                                 if (target_type == TypeManager.byte_type) {
1624                                         if (!CheckRange (ec, v, target_type, Byte.MaxValue))
1625                                                 return null;
1626                                         return new ByteConstant ((byte) v);
1627                                 }
1628                                 if (target_type == TypeManager.sbyte_type) {
1629                                         if (!CheckRange (ec, v, target_type, (ulong) SByte.MaxValue))
1630                                                 return null;
1631                                         return new SByteConstant ((sbyte) v);
1632                                 }
1633                                 if (target_type == TypeManager.short_type) {
1634                                         if (!CheckRange (ec, v, target_type, (ulong) Int16.MaxValue))
1635                                                 return null;
1636                                         return new ShortConstant ((short) v);
1637                                 }
1638                                 if (target_type == TypeManager.ushort_type) {
1639                                         if (!CheckRange (ec, v, target_type, UInt16.MaxValue))
1640                                                 return null;
1641                                         return new UShortConstant ((ushort) v);
1642                                 }
1643                                 if (target_type == TypeManager.int32_type) {
1644                                         if (!CheckRange (ec, v, target_type, Int32.MaxValue))
1645                                                 return null;
1646                                         return new IntConstant ((int) v);
1647                                 }
1648                                 if (target_type == TypeManager.uint32_type) {
1649                                         if (!CheckRange (ec, v, target_type, UInt32.MaxValue))
1650                                                 return null;
1651                                         return new UIntConstant ((uint) v);
1652                                 }
1653                                 if (target_type == TypeManager.int64_type) {
1654                                         if (!CheckRange (ec, v, target_type, (ulong) Int64.MaxValue))
1655                                                 return null;
1656                                         return new LongConstant ((long) v);
1657                                 }
1658                                 if (target_type == TypeManager.float_type)
1659                                         return new FloatConstant ((float) v);
1660                                 if (target_type == TypeManager.double_type)
1661                                         return new DoubleConstant ((double) v);
1662                                 if (target_type == TypeManager.char_type) {
1663                                         if (!CheckRange (ec, v, target_type, Char.MaxValue))
1664                                                 return null;
1665                                         return new CharConstant ((char) v);
1666                                 }
1667                                 if (target_type == TypeManager.decimal_type)
1668                                         return new DecimalConstant ((decimal) v);
1669                         }
1670                         if (real_expr is FloatConstant){
1671                                 float v = ((FloatConstant) real_expr).Value;
1672
1673                                 if (target_type == TypeManager.byte_type)
1674                                         return new ByteConstant ((byte) v);
1675                                 if (target_type == TypeManager.sbyte_type)
1676                                         return new SByteConstant ((sbyte) v);
1677                                 if (target_type == TypeManager.short_type)
1678                                         return new ShortConstant ((short) v);
1679                                 if (target_type == TypeManager.ushort_type)
1680                                         return new UShortConstant ((ushort) v);
1681                                 if (target_type == TypeManager.int32_type)
1682                                         return new IntConstant ((int) v);
1683                                 if (target_type == TypeManager.uint32_type)
1684                                         return new UIntConstant ((uint) v);
1685                                 if (target_type == TypeManager.int64_type)
1686                                         return new LongConstant ((long) v);
1687                                 if (target_type == TypeManager.uint64_type)
1688                                         return new ULongConstant ((ulong) v);
1689                                 if (target_type == TypeManager.double_type)
1690                                         return new DoubleConstant ((double) v);
1691                                 if (target_type == TypeManager.char_type)
1692                                         return new CharConstant ((char) v);
1693                                 if (target_type == TypeManager.decimal_type)
1694                                         return new DecimalConstant ((decimal) v);
1695                         }
1696                         if (real_expr is DoubleConstant){
1697                                 double v = ((DoubleConstant) real_expr).Value;
1698
1699                                 if (target_type == TypeManager.byte_type){
1700                                         return new ByteConstant ((byte) v);
1701                                 } if (target_type == TypeManager.sbyte_type)
1702                                         return new SByteConstant ((sbyte) v);
1703                                 if (target_type == TypeManager.short_type)
1704                                         return new ShortConstant ((short) v);
1705                                 if (target_type == TypeManager.ushort_type)
1706                                         return new UShortConstant ((ushort) v);
1707                                 if (target_type == TypeManager.int32_type)
1708                                         return new IntConstant ((int) v);
1709                                 if (target_type == TypeManager.uint32_type)
1710                                         return new UIntConstant ((uint) v);
1711                                 if (target_type == TypeManager.int64_type)
1712                                         return new LongConstant ((long) v);
1713                                 if (target_type == TypeManager.uint64_type)
1714                                         return new ULongConstant ((ulong) v);
1715                                 if (target_type == TypeManager.float_type)
1716                                         return new FloatConstant ((float) v);
1717                                 if (target_type == TypeManager.char_type)
1718                                         return new CharConstant ((char) v);
1719                                 if (target_type == TypeManager.decimal_type)
1720                                         return new DecimalConstant ((decimal) v);
1721                         }
1722
1723                         if (real_expr is CharConstant){
1724                                 char v = ((CharConstant) real_expr).Value;
1725
1726                                 if (target_type == TypeManager.byte_type) {
1727                                         if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
1728                                                 return null;
1729                                         return new ByteConstant ((byte) v);
1730                                 }
1731                                 if (target_type == TypeManager.sbyte_type) {
1732                                         if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
1733                                                 return null;
1734                                         return new SByteConstant ((sbyte) v);
1735                                 }
1736                                 if (target_type == TypeManager.short_type) {
1737                                         if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
1738                                                 return null;
1739                                         return new ShortConstant ((short) v);
1740                                 }
1741                                 if (target_type == TypeManager.int32_type)
1742                                         return new IntConstant ((int) v);
1743                                 if (target_type == TypeManager.uint32_type)
1744                                         return new UIntConstant ((uint) v);
1745                                 if (target_type == TypeManager.int64_type)
1746                                         return new LongConstant ((long) v);
1747                                 if (target_type == TypeManager.uint64_type)
1748                                         return new ULongConstant ((ulong) v);
1749                                 if (target_type == TypeManager.float_type)
1750                                         return new FloatConstant ((float) v);
1751                                 if (target_type == TypeManager.double_type)
1752                                         return new DoubleConstant ((double) v);
1753                                 if (target_type == TypeManager.char_type) {
1754                                         if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
1755                                                 return null;
1756                                         return new CharConstant ((char) v);
1757                                 }
1758                                 if (target_type == TypeManager.decimal_type)
1759                                         return new DecimalConstant ((decimal) v);
1760                         }
1761
1762                         return null;
1763                 }
1764
1765                 public override Expression DoResolve (EmitContext ec)
1766                 {
1767                         expr = expr.Resolve (ec);
1768                         if (expr == null)
1769                                 return null;
1770
1771                         type = ec.DeclSpace.ResolveType (target_type, false, Location);
1772
1773                         if (type == null)
1774                                 return null;
1775
1776                         CheckObsoleteAttribute (type);
1777
1778                         if (type.IsAbstract && type.IsSealed) {
1779                                 Report.Error (716, loc, "Cannot convert to static type '{0}'", TypeManager.CSharpName (type));
1780                                 return null;
1781                         }
1782
1783                         eclass = ExprClass.Value;
1784
1785                         if (expr is Constant){
1786                                 Expression e = TryReduce (ec, type);
1787
1788                                 if (e != null)
1789                                         return e;
1790                         }
1791
1792                         if (type.IsPointer && !ec.InUnsafe) {
1793                                 UnsafeError (loc);
1794                                 return null;
1795                         }
1796                         expr = Convert.ExplicitConversion (ec, expr, type, loc);
1797                         return expr;
1798                 }
1799
1800                 public override void Emit (EmitContext ec)
1801                 {
1802                         //
1803                         // This one will never happen
1804                         //
1805                         throw new Exception ("Should not happen");
1806                 }
1807         }
1808
1809         /// <summary>
1810         ///   Binary operators
1811         /// </summary>
1812         public class Binary : Expression {
1813                 public enum Operator : byte {
1814                         Multiply, Division, Modulus,
1815                         Addition, Subtraction,
1816                         LeftShift, RightShift,
1817                         LessThan, GreaterThan, LessThanOrEqual, GreaterThanOrEqual,
1818                         Equality, Inequality,
1819                         BitwiseAnd,
1820                         ExclusiveOr,
1821                         BitwiseOr,
1822                         LogicalAnd,
1823                         LogicalOr,
1824                         TOP
1825                 }
1826
1827                 Operator oper;
1828                 Expression left, right;
1829
1830                 // This must be kept in sync with Operator!!!
1831                 public static readonly string [] oper_names;
1832
1833                 static Binary ()
1834                 {
1835                         oper_names = new string [(int) Operator.TOP];
1836
1837                         oper_names [(int) Operator.Multiply] = "op_Multiply";
1838                         oper_names [(int) Operator.Division] = "op_Division";
1839                         oper_names [(int) Operator.Modulus] = "op_Modulus";
1840                         oper_names [(int) Operator.Addition] = "op_Addition";
1841                         oper_names [(int) Operator.Subtraction] = "op_Subtraction";
1842                         oper_names [(int) Operator.LeftShift] = "op_LeftShift";
1843                         oper_names [(int) Operator.RightShift] = "op_RightShift";
1844                         oper_names [(int) Operator.LessThan] = "op_LessThan";
1845                         oper_names [(int) Operator.GreaterThan] = "op_GreaterThan";
1846                         oper_names [(int) Operator.LessThanOrEqual] = "op_LessThanOrEqual";
1847                         oper_names [(int) Operator.GreaterThanOrEqual] = "op_GreaterThanOrEqual";
1848                         oper_names [(int) Operator.Equality] = "op_Equality";
1849                         oper_names [(int) Operator.Inequality] = "op_Inequality";
1850                         oper_names [(int) Operator.BitwiseAnd] = "op_BitwiseAnd";
1851                         oper_names [(int) Operator.BitwiseOr] = "op_BitwiseOr";
1852                         oper_names [(int) Operator.ExclusiveOr] = "op_ExclusiveOr";
1853                         oper_names [(int) Operator.LogicalOr] = "op_LogicalOr";
1854                         oper_names [(int) Operator.LogicalAnd] = "op_LogicalAnd";
1855                 }
1856
1857                 public Binary (Operator oper, Expression left, Expression right, Location loc)
1858                 {
1859                         this.oper = oper;
1860                         this.left = left;
1861                         this.right = right;
1862                         this.loc = loc;
1863                 }
1864
1865                 public Operator Oper {
1866                         get {
1867                                 return oper;
1868                         }
1869                         set {
1870                                 oper = value;
1871                         }
1872                 }
1873
1874                 public Expression Left {
1875                         get {
1876                                 return left;
1877                         }
1878                         set {
1879                                 left = value;
1880                         }
1881                 }
1882
1883                 public Expression Right {
1884                         get {
1885                                 return right;
1886                         }
1887                         set {
1888                                 right = value;
1889                         }
1890                 }
1891
1892
1893                 /// <summary>
1894                 ///   Returns a stringified representation of the Operator
1895                 /// </summary>
1896                 static string OperName (Operator oper)
1897                 {
1898                         switch (oper){
1899                         case Operator.Multiply:
1900                                 return "*";
1901                         case Operator.Division:
1902                                 return "/";
1903                         case Operator.Modulus:
1904                                 return "%";
1905                         case Operator.Addition:
1906                                 return "+";
1907                         case Operator.Subtraction:
1908                                 return "-";
1909                         case Operator.LeftShift:
1910                                 return "<<";
1911                         case Operator.RightShift:
1912                                 return ">>";
1913                         case Operator.LessThan:
1914                                 return "<";
1915                         case Operator.GreaterThan:
1916                                 return ">";
1917                         case Operator.LessThanOrEqual:
1918                                 return "<=";
1919                         case Operator.GreaterThanOrEqual:
1920                                 return ">=";
1921                         case Operator.Equality:
1922                                 return "==";
1923                         case Operator.Inequality:
1924                                 return "!=";
1925                         case Operator.BitwiseAnd:
1926                                 return "&";
1927                         case Operator.BitwiseOr:
1928                                 return "|";
1929                         case Operator.ExclusiveOr:
1930                                 return "^";
1931                         case Operator.LogicalOr:
1932                                 return "||";
1933                         case Operator.LogicalAnd:
1934                                 return "&&";
1935                         }
1936
1937                         return oper.ToString ();
1938                 }
1939
1940                 public override string ToString ()
1941                 {
1942                         return "operator " + OperName (oper) + "(" + left.ToString () + ", " +
1943                                 right.ToString () + ")";
1944                 }
1945
1946                 Expression ForceConversion (EmitContext ec, Expression expr, Type target_type)
1947                 {
1948                         if (expr.Type == target_type)
1949                                 return expr;
1950
1951                         return Convert.ImplicitConversion (ec, expr, target_type, loc);
1952                 }
1953
1954                 public static void Error_OperatorAmbiguous (Location loc, Operator oper, Type l, Type r)
1955                 {
1956                         Report.Error (
1957                                 34, loc, "Operator `" + OperName (oper)
1958                                 + "' is ambiguous on operands of type `"
1959                                 + TypeManager.CSharpName (l) + "' "
1960                                 + "and `" + TypeManager.CSharpName (r)
1961                                 + "'");
1962                 }
1963
1964                 bool IsOfType (EmitContext ec, Type l, Type r, Type t, bool check_user_conversions)
1965                 {
1966                         if ((l == t) || (r == t))
1967                                 return true;
1968
1969                         if (!check_user_conversions)
1970                                 return false;
1971
1972                         if (Convert.ImplicitUserConversionExists (ec, l, t))
1973                                 return true;
1974                         else if (Convert.ImplicitUserConversionExists (ec, r, t))
1975                                 return true;
1976                         else
1977                                 return false;
1978                 }
1979
1980                 //
1981                 // Note that handling the case l == Decimal || r == Decimal
1982                 // is taken care of by the Step 1 Operator Overload resolution.
1983                 //
1984                 // If `check_user_conv' is true, we also check whether a user-defined conversion
1985                 // exists.  Note that we only need to do this if both arguments are of a user-defined
1986                 // type, otherwise ConvertImplict() already finds the user-defined conversion for us,
1987                 // so we don't explicitly check for performance reasons.
1988                 //
1989                 bool DoNumericPromotions (EmitContext ec, Type l, Type r, bool check_user_conv)
1990                 {
1991                         if (IsOfType (ec, l, r, TypeManager.double_type, check_user_conv)){
1992                                 //
1993                                 // If either operand is of type double, the other operand is
1994                                 // conveted to type double.
1995                                 //
1996                                 if (r != TypeManager.double_type)
1997                                         right = Convert.ImplicitConversion (ec, right, TypeManager.double_type, loc);
1998                                 if (l != TypeManager.double_type)
1999                                         left = Convert.ImplicitConversion (ec, left, TypeManager.double_type, loc);
2000
2001                                 type = TypeManager.double_type;
2002                         } else if (IsOfType (ec, l, r, TypeManager.float_type, check_user_conv)){
2003                                 //
2004                                 // if either operand is of type float, the other operand is
2005                                 // converted to type float.
2006                                 //
2007                                 if (r != TypeManager.double_type)
2008                                         right = Convert.ImplicitConversion (ec, right, TypeManager.float_type, loc);
2009                                 if (l != TypeManager.double_type)
2010                                         left = Convert.ImplicitConversion (ec, left, TypeManager.float_type, loc);
2011                                 type = TypeManager.float_type;
2012                         } else if (IsOfType (ec, l, r, TypeManager.uint64_type, check_user_conv)){
2013                                 Expression e;
2014                                 Type other;
2015                                 //
2016                                 // If either operand is of type ulong, the other operand is
2017                                 // converted to type ulong.  or an error ocurrs if the other
2018                                 // operand is of type sbyte, short, int or long
2019                                 //
2020                                 if (l == TypeManager.uint64_type){
2021                                         if (r != TypeManager.uint64_type){
2022                                                 if (right is IntConstant){
2023                                                         IntConstant ic = (IntConstant) right;
2024
2025                                                         e = Convert.TryImplicitIntConversion (l, ic);
2026                                                         if (e != null)
2027                                                                 right = e;
2028                                                 } else if (right is LongConstant){
2029                                                         long ll = ((LongConstant) right).Value;
2030
2031                                                         if (ll >= 0)
2032                                                                 right = new ULongConstant ((ulong) ll);
2033                                                 } else {
2034                                                         e = Convert.ImplicitNumericConversion (ec, right, l, loc);
2035                                                         if (e != null)
2036                                                                 right = e;
2037                                                 }
2038                                         }
2039                                         other = right.Type;
2040                                 } else {
2041                                         if (left is IntConstant){
2042                                                 e = Convert.TryImplicitIntConversion (r, (IntConstant) left);
2043                                                 if (e != null)
2044                                                         left = e;
2045                                         } else if (left is LongConstant){
2046                                                 long ll = ((LongConstant) left).Value;
2047
2048                                                 if (ll > 0)
2049                                                         left = new ULongConstant ((ulong) ll);
2050                                         } else {
2051                                                 e = Convert.ImplicitNumericConversion (ec, left, r, loc);
2052                                                 if (e != null)
2053                                                         left = e;
2054                                         }
2055                                         other = left.Type;
2056                                 }
2057
2058                                 if ((other == TypeManager.sbyte_type) ||
2059                                     (other == TypeManager.short_type) ||
2060                                     (other == TypeManager.int32_type) ||
2061                                     (other == TypeManager.int64_type))
2062                                         Error_OperatorAmbiguous (loc, oper, l, r);
2063                                 else {
2064                                         left = ForceConversion (ec, left, TypeManager.uint64_type);
2065                                         right = ForceConversion (ec, right, TypeManager.uint64_type);
2066                                 }
2067                                 type = TypeManager.uint64_type;
2068                         } else if (IsOfType (ec, l, r, TypeManager.int64_type, check_user_conv)){
2069                                 //
2070                                 // If either operand is of type long, the other operand is converted
2071                                 // to type long.
2072                                 //
2073                                 if (l != TypeManager.int64_type)
2074                                         left = Convert.ImplicitConversion (ec, left, TypeManager.int64_type, loc);
2075                                 if (r != TypeManager.int64_type)
2076                                         right = Convert.ImplicitConversion (ec, right, TypeManager.int64_type, loc);
2077
2078                                 type = TypeManager.int64_type;
2079                         } else if (IsOfType (ec, l, r, TypeManager.uint32_type, check_user_conv)){
2080                                 //
2081                                 // If either operand is of type uint, and the other
2082                                 // operand is of type sbyte, short or int, othe operands are
2083                                 // converted to type long (unless we have an int constant).
2084                                 //
2085                                 Type other = null;
2086
2087                                 if (l == TypeManager.uint32_type){
2088                                         if (right is IntConstant){
2089                                                 IntConstant ic = (IntConstant) right;
2090                                                 int val = ic.Value;
2091
2092                                                 if (val >= 0){
2093                                                         right = new UIntConstant ((uint) val);
2094                                                         type = l;
2095
2096                                                         return true;
2097                                                 }
2098                                         }
2099                                         other = r;
2100                                 } else if (r == TypeManager.uint32_type){
2101                                         if (left is IntConstant){
2102                                                 IntConstant ic = (IntConstant) left;
2103                                                 int val = ic.Value;
2104
2105                                                 if (val >= 0){
2106                                                         left = new UIntConstant ((uint) val);
2107                                                         type = r;
2108                                                         return true;
2109                                                 }
2110                                         }
2111
2112                                         other = l;
2113                                 }
2114
2115                                 if ((other == TypeManager.sbyte_type) ||
2116                                     (other == TypeManager.short_type) ||
2117                                     (other == TypeManager.int32_type)){
2118                                         left = ForceConversion (ec, left, TypeManager.int64_type);
2119                                         right = ForceConversion (ec, right, TypeManager.int64_type);
2120                                         type = TypeManager.int64_type;
2121                                 } else {
2122                                         //
2123                                         // if either operand is of type uint, the other
2124                                         // operand is converd to type uint
2125                                         //
2126                                         left = ForceConversion (ec, left, TypeManager.uint32_type);
2127                                         right = ForceConversion (ec, right, TypeManager.uint32_type);
2128                                         type = TypeManager.uint32_type;
2129                                 }
2130                         } else if (l == TypeManager.decimal_type || r == TypeManager.decimal_type){
2131                                 if (l != TypeManager.decimal_type)
2132                                         left = Convert.ImplicitConversion (ec, left, TypeManager.decimal_type, loc);
2133
2134                                 if (r != TypeManager.decimal_type)
2135                                         right = Convert.ImplicitConversion (ec, right, TypeManager.decimal_type, loc);
2136                                 type = TypeManager.decimal_type;
2137                         } else {
2138                                 left = ForceConversion (ec, left, TypeManager.int32_type);
2139                                 right = ForceConversion (ec, right, TypeManager.int32_type);
2140
2141                                 type = TypeManager.int32_type;
2142                         }
2143
2144                         return (left != null) && (right != null);
2145                 }
2146
2147                 static public void Error_OperatorCannotBeApplied (Location loc, string name, Type l, Type r)
2148                 {
2149                         Report.Error (19, loc,
2150                                "Operator " + name + " cannot be applied to operands of type `" +
2151                                TypeManager.CSharpName (l) + "' and `" +
2152                                TypeManager.CSharpName (r) + "'");
2153                 }
2154
2155                 void Error_OperatorCannotBeApplied ()
2156                 {
2157                         Error_OperatorCannotBeApplied (loc, OperName (oper), left.Type, right.Type);
2158                 }
2159
2160                 static bool is_unsigned (Type t)
2161                 {
2162                         return (t == TypeManager.uint32_type || t == TypeManager.uint64_type ||
2163                                 t == TypeManager.short_type || t == TypeManager.byte_type);
2164                 }
2165
2166                 static bool is_user_defined (Type t)
2167                 {
2168                         if (t.IsSubclassOf (TypeManager.value_type) &&
2169                             (!TypeManager.IsBuiltinType (t) || t == TypeManager.decimal_type))
2170                                 return true;
2171                         else
2172                                 return false;
2173                 }
2174
2175                 Expression Make32or64 (EmitContext ec, Expression e)
2176                 {
2177                         Type t= e.Type;
2178
2179                         if (t == TypeManager.int32_type || t == TypeManager.uint32_type ||
2180                             t == TypeManager.int64_type || t == TypeManager.uint64_type)
2181                                 return e;
2182                         Expression ee = Convert.ImplicitConversion (ec, e, TypeManager.int32_type, loc);
2183                         if (ee != null)
2184                                 return ee;
2185                         ee = Convert.ImplicitConversion (ec, e, TypeManager.uint32_type, loc);
2186                         if (ee != null)
2187                                 return ee;
2188                         ee = Convert.ImplicitConversion (ec, e, TypeManager.int64_type, loc);
2189                         if (ee != null)
2190                                 return ee;
2191                         ee = Convert.ImplicitConversion (ec, e, TypeManager.uint64_type, loc);
2192                         if (ee != null)
2193                                 return ee;
2194                         return null;
2195                 }
2196
2197                 Expression CheckShiftArguments (EmitContext ec)
2198                 {
2199                         Expression e;
2200
2201                         e = ForceConversion (ec, right, TypeManager.int32_type);
2202                         if (e == null){
2203                                 Error_OperatorCannotBeApplied ();
2204                                 return null;
2205                         }
2206                         right = e;
2207
2208                         if (((e = Convert.ImplicitConversion (ec, left, TypeManager.int32_type, loc)) != null) ||
2209                             ((e = Convert.ImplicitConversion (ec, left, TypeManager.uint32_type, loc)) != null) ||
2210                             ((e = Convert.ImplicitConversion (ec, left, TypeManager.int64_type, loc)) != null) ||
2211                             ((e = Convert.ImplicitConversion (ec, left, TypeManager.uint64_type, loc)) != null)){
2212                                 left = e;
2213                                 type = e.Type;
2214
2215                                 if (type == TypeManager.int32_type || type == TypeManager.uint32_type){
2216                                         right = new Binary (Binary.Operator.BitwiseAnd, right, new IntLiteral (31), loc);
2217                                         right = right.DoResolve (ec);
2218                                 } else {
2219                                         right = new Binary (Binary.Operator.BitwiseAnd, right, new IntLiteral (63), loc);
2220                                         right = right.DoResolve (ec);
2221                                 }
2222
2223                                 return this;
2224                         }
2225                         Error_OperatorCannotBeApplied ();
2226                         return null;
2227                 }
2228
2229                 Expression ResolveOperator (EmitContext ec)
2230                 {
2231                         Type l = left.Type;
2232                         Type r = right.Type;
2233
2234                         //
2235                         // Special cases: string comapred to null
2236                         //
2237                         if (oper == Operator.Equality || oper == Operator.Inequality){
2238                                 if ((l == TypeManager.string_type && (right is NullLiteral)) ||
2239                                     (r == TypeManager.string_type && (left is NullLiteral))){
2240                                         Type = TypeManager.bool_type;
2241
2242                                         return this;
2243                                 }
2244
2245                                 // IntPtr equality
2246                                 if (l == TypeManager.intptr_type && r == TypeManager.intptr_type) {
2247                                         Type = TypeManager.bool_type;
2248
2249                                         return this;
2250                                 }
2251                         }
2252
2253                         //
2254                         // Do not perform operator overload resolution when both sides are
2255                         // built-in types
2256                         //
2257                         if (!(TypeManager.IsCLRType (l) && TypeManager.IsCLRType (r))){
2258                                 //
2259                                 // Step 1: Perform Operator Overload location
2260                                 //
2261                                 Expression left_expr, right_expr;
2262
2263                                 string op = oper_names [(int) oper];
2264
2265                                 MethodGroupExpr union;
2266                                 left_expr = MemberLookup (ec, l, op, MemberTypes.Method, AllBindingFlags, loc);
2267                                 if (r != l){
2268                                         right_expr = MemberLookup (
2269                                                 ec, r, op, MemberTypes.Method, AllBindingFlags, loc);
2270                                         union = Invocation.MakeUnionSet (left_expr, right_expr, loc);
2271                                 } else
2272                                         union = (MethodGroupExpr) left_expr;
2273
2274                                 if (union != null) {
2275                                         ArrayList args = new ArrayList (2);
2276                                         args.Add (new Argument (left, Argument.AType.Expression));
2277                                         args.Add (new Argument (right, Argument.AType.Expression));
2278
2279                                         MethodBase method = Invocation.OverloadResolve (
2280                                                 ec, union, args, true, Location.Null);
2281
2282                                         if (method != null) {
2283                                                 MethodInfo mi = (MethodInfo) method;
2284
2285                                                 return new BinaryMethod (mi.ReturnType, method, args);
2286                                         }
2287                                 }
2288                         }
2289
2290                         //
2291                         // Step 0: String concatenation (because overloading will get this wrong)
2292                         //
2293                         if (oper == Operator.Addition){
2294                                 //
2295                                 // If any of the arguments is a string, cast to string
2296                                 //
2297
2298                                 // Simple constant folding
2299                                 if (left is StringConstant && right is StringConstant)
2300                                         return new StringConstant (((StringConstant) left).Value + ((StringConstant) right).Value);
2301
2302                                 if (l == TypeManager.string_type || r == TypeManager.string_type) {
2303
2304                                         if (r == TypeManager.void_type || l == TypeManager.void_type) {
2305                                                 Error_OperatorCannotBeApplied ();
2306                                                 return null;
2307                                         }
2308
2309                                         // try to fold it in on the left
2310                                         if (left is StringConcat) {
2311
2312                                                 //
2313                                                 // We have to test here for not-null, since we can be doubly-resolved
2314                                                 // take care of not appending twice
2315                                                 //
2316                                                 if (type == null){
2317                                                         type = TypeManager.string_type;
2318                                                         ((StringConcat) left).Append (ec, right);
2319                                                         return left.Resolve (ec);
2320                                                 } else {
2321                                                         return left;
2322                                                 }
2323                                         }
2324
2325                                         // Otherwise, start a new concat expression
2326                                         return new StringConcat (ec, loc, left, right).Resolve (ec);
2327                                 }
2328
2329                                 //
2330                                 // Transform a + ( - b) into a - b
2331                                 //
2332                                 if (right is Unary){
2333                                         Unary right_unary = (Unary) right;
2334
2335                                         if (right_unary.Oper == Unary.Operator.UnaryNegation){
2336                                                 oper = Operator.Subtraction;
2337                                                 right = right_unary.Expr;
2338                                                 r = right.Type;
2339                                         }
2340                                 }
2341                         }
2342
2343                         if (oper == Operator.Equality || oper == Operator.Inequality){
2344                                 if (l == TypeManager.bool_type || r == TypeManager.bool_type){
2345                                         if (r != TypeManager.bool_type || l != TypeManager.bool_type){
2346                                                 Error_OperatorCannotBeApplied ();
2347                                                 return null;
2348                                         }
2349
2350                                         type = TypeManager.bool_type;
2351                                         return this;
2352                                 }
2353
2354                                 //
2355                                 // operator != (object a, object b)
2356                                 // operator == (object a, object b)
2357                                 //
2358                                 // For this to be used, both arguments have to be reference-types.
2359                                 // Read the rationale on the spec (14.9.6)
2360                                 //
2361                                 // Also, if at compile time we know that the classes do not inherit
2362                                 // one from the other, then we catch the error there.
2363                                 //
2364                                 if (!(l.IsValueType || r.IsValueType)){
2365                                         type = TypeManager.bool_type;
2366
2367                                         if (l == r)
2368                                                 return this;
2369
2370                                         if (l.IsSubclassOf (r) || r.IsSubclassOf (l))
2371                                                 return this;
2372
2373                                         //
2374                                         // Also, a standard conversion must exist from either one
2375                                         //
2376                                         if (!(Convert.ImplicitStandardConversionExists (left, r) ||
2377                                               Convert.ImplicitStandardConversionExists (right, l))){
2378                                                 Error_OperatorCannotBeApplied ();
2379                                                 return null;
2380                                         }
2381                                         //
2382                                         // We are going to have to convert to an object to compare
2383                                         //
2384                                         if (l != TypeManager.object_type)
2385                                                 left = new EmptyCast (left, TypeManager.object_type);
2386                                         if (r != TypeManager.object_type)
2387                                                 right = new EmptyCast (right, TypeManager.object_type);
2388
2389                                         //
2390                                         // FIXME: CSC here catches errors cs254 and cs252
2391                                         //
2392                                         return this;
2393                                 }
2394
2395                                 //
2396                                 // One of them is a valuetype, but the other one is not.
2397                                 //
2398                                 if (!l.IsValueType || !r.IsValueType) {
2399                                         Error_OperatorCannotBeApplied ();
2400                                         return null;
2401                                 }
2402                         }
2403
2404                         // Only perform numeric promotions on:
2405                         // +, -, *, /, %, &, |, ^, ==, !=, <, >, <=, >=
2406                         //
2407                         if (oper == Operator.Addition || oper == Operator.Subtraction) {
2408                                 if (l.IsSubclassOf (TypeManager.delegate_type)){
2409                                         if ((right.eclass == ExprClass.MethodGroup) &&
2410                                             (RootContext.Version != LanguageVersion.ISO_1)){
2411                                                 Expression tmp = Convert.ImplicitConversionRequired (ec, right, l, loc);
2412                                                 if (tmp == null)
2413                                                         return null;
2414                                                 right = tmp;
2415                                                 r = right.Type;
2416                                         }
2417
2418                                         if (r.IsSubclassOf (TypeManager.delegate_type)){
2419                                                 MethodInfo method;
2420                                                 ArrayList args = new ArrayList (2);
2421
2422                                                 args = new ArrayList (2);
2423                                                 args.Add (new Argument (left, Argument.AType.Expression));
2424                                                 args.Add (new Argument (right, Argument.AType.Expression));
2425
2426                                                 if (oper == Operator.Addition)
2427                                                         method = TypeManager.delegate_combine_delegate_delegate;
2428                                                 else
2429                                                         method = TypeManager.delegate_remove_delegate_delegate;
2430
2431                                                 if (l != r) {
2432                                                         Error_OperatorCannotBeApplied ();
2433                                                         return null;
2434                                                 }
2435
2436                                                 return new BinaryDelegate (l, method, args);
2437                                         }
2438                                 }
2439
2440                                 //
2441                                 // Pointer arithmetic:
2442                                 //
2443                                 // T* operator + (T* x, int y);
2444                                 // T* operator + (T* x, uint y);
2445                                 // T* operator + (T* x, long y);
2446                                 // T* operator + (T* x, ulong y);
2447                                 //
2448                                 // T* operator + (int y,   T* x);
2449                                 // T* operator + (uint y,  T *x);
2450                                 // T* operator + (long y,  T *x);
2451                                 // T* operator + (ulong y, T *x);
2452                                 //
2453                                 // T* operator - (T* x, int y);
2454                                 // T* operator - (T* x, uint y);
2455                                 // T* operator - (T* x, long y);
2456                                 // T* operator - (T* x, ulong y);
2457                                 //
2458                                 // long operator - (T* x, T *y)
2459                                 //
2460                                 if (l.IsPointer){
2461                                         if (r.IsPointer && oper == Operator.Subtraction){
2462                                                 if (r == l)
2463                                                         return new PointerArithmetic (
2464                                                                 false, left, right, TypeManager.int64_type,
2465                                                                 loc).Resolve (ec);
2466                                         } else {
2467                                                 Expression t = Make32or64 (ec, right);
2468                                                 if (t != null)
2469                                                         return new PointerArithmetic (oper == Operator.Addition, left, t, l, loc).Resolve (ec);
2470                                         }
2471                                 } else if (r.IsPointer && oper == Operator.Addition){
2472                                         Expression t = Make32or64 (ec, left);
2473                                         if (t != null)
2474                                                 return new PointerArithmetic (true, right, t, r, loc).Resolve (ec);
2475                                 }
2476                         }
2477
2478                         //
2479                         // Enumeration operators
2480                         //
2481                         bool lie = TypeManager.IsEnumType (l);
2482                         bool rie = TypeManager.IsEnumType (r);
2483                         if (lie || rie){
2484                                 Expression temp;
2485
2486                                 // U operator - (E e, E f)
2487                                 if (lie && rie){
2488                                         if (oper == Operator.Subtraction){
2489                                                 if (l == r){
2490                                                         type = TypeManager.EnumToUnderlying (l);
2491                                                         return this;
2492                                                 }
2493                                                 Error_OperatorCannotBeApplied ();
2494                                                 return null;
2495                                         }
2496                                 }
2497
2498                                 //
2499                                 // operator + (E e, U x)
2500                                 // operator - (E e, U x)
2501                                 //
2502                                 if (oper == Operator.Addition || oper == Operator.Subtraction){
2503                                         Type enum_type = lie ? l : r;
2504                                         Type other_type = lie ? r : l;
2505                                         Type underlying_type = TypeManager.EnumToUnderlying (enum_type);
2506
2507                                         if (underlying_type != other_type){
2508                                                 temp = Convert.ImplicitConversion (ec, lie ? right : left, underlying_type, loc);
2509                                                 if (temp != null){
2510                                                         if (lie)
2511                                                                 right = temp;
2512                                                         else
2513                                                                 left = temp;
2514                                                         type = enum_type;
2515                                                         return this;
2516                                                 }
2517
2518                                                 Error_OperatorCannotBeApplied ();
2519                                                 return null;
2520                                         }
2521
2522                                         type = enum_type;
2523                                         return this;
2524                                 }
2525
2526                                 if (!rie){
2527                                         temp = Convert.ImplicitConversion (ec, right, l, loc);
2528                                         if (temp != null)
2529                                                 right = temp;
2530                                         else {
2531                                                 Error_OperatorCannotBeApplied ();
2532                                                 return null;
2533                                         }
2534                                 } if (!lie){
2535                                         temp = Convert.ImplicitConversion (ec, left, r, loc);
2536                                         if (temp != null){
2537                                                 left = temp;
2538                                                 l = r;
2539                                         } else {
2540                                                 Error_OperatorCannotBeApplied ();
2541                                                 return null;
2542                                         }
2543                                 }
2544
2545                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2546                                     oper == Operator.LessThanOrEqual || oper == Operator.LessThan ||
2547                                     oper == Operator.GreaterThanOrEqual || oper == Operator.GreaterThan){
2548                                         if (left.Type != right.Type){
2549                                                 Error_OperatorCannotBeApplied ();
2550                                                 return null;
2551                                         }
2552                                         type = TypeManager.bool_type;
2553                                         return this;
2554                                 }
2555
2556                                 if (oper == Operator.BitwiseAnd ||
2557                                     oper == Operator.BitwiseOr ||
2558                                     oper == Operator.ExclusiveOr){
2559                                         type = l;
2560                                         return this;
2561                                 }
2562                                 Error_OperatorCannotBeApplied ();
2563                                 return null;
2564                         }
2565
2566                         if (oper == Operator.LeftShift || oper == Operator.RightShift)
2567                                 return CheckShiftArguments (ec);
2568
2569                         if (oper == Operator.LogicalOr || oper == Operator.LogicalAnd){
2570                                 if (l == TypeManager.bool_type && r == TypeManager.bool_type) {
2571                                         type = TypeManager.bool_type;
2572                                         return this;
2573                                 }
2574
2575                                 if (l != r) {
2576                                         Error_OperatorCannotBeApplied ();
2577                                         return null;
2578                                 }
2579
2580                                 Expression e = new ConditionalLogicalOperator (
2581                                         oper == Operator.LogicalAnd, left, right, l, loc);
2582                                 return e.Resolve (ec);
2583                         }
2584
2585                         //
2586                         // operator & (bool x, bool y)
2587                         // operator | (bool x, bool y)
2588                         // operator ^ (bool x, bool y)
2589                         //
2590                         if (l == TypeManager.bool_type && r == TypeManager.bool_type){
2591                                 if (oper == Operator.BitwiseAnd ||
2592                                     oper == Operator.BitwiseOr ||
2593                                     oper == Operator.ExclusiveOr){
2594                                         type = l;
2595                                         return this;
2596                                 }
2597                         }
2598
2599                         //
2600                         // Pointer comparison
2601                         //
2602                         if (l.IsPointer && r.IsPointer){
2603                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2604                                     oper == Operator.LessThan || oper == Operator.LessThanOrEqual ||
2605                                     oper == Operator.GreaterThan || oper == Operator.GreaterThanOrEqual){
2606                                         type = TypeManager.bool_type;
2607                                         return this;
2608                                 }
2609                         }
2610
2611                         //
2612                         // This will leave left or right set to null if there is an error
2613                         //
2614                         bool check_user_conv = is_user_defined (l) && is_user_defined (r);
2615                         DoNumericPromotions (ec, l, r, check_user_conv);
2616                         if (left == null || right == null){
2617                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
2618                                 return null;
2619                         }
2620
2621                         //
2622                         // reload our cached types if required
2623                         //
2624                         l = left.Type;
2625                         r = right.Type;
2626
2627                         if (oper == Operator.BitwiseAnd ||
2628                             oper == Operator.BitwiseOr ||
2629                             oper == Operator.ExclusiveOr){
2630                                 if (l == r){
2631                                         if (((l == TypeManager.int32_type) ||
2632                                              (l == TypeManager.uint32_type) ||
2633                                              (l == TypeManager.short_type) ||
2634                                              (l == TypeManager.ushort_type) ||
2635                                              (l == TypeManager.int64_type) ||
2636                                              (l == TypeManager.uint64_type))){
2637                                                 type = l;
2638                                         } else {
2639                                                 Error_OperatorCannotBeApplied ();
2640                                                 return null;
2641                                         }
2642                                 } else {
2643                                         Error_OperatorCannotBeApplied ();
2644                                         return null;
2645                                 }
2646                         }
2647
2648                         if (oper == Operator.Equality ||
2649                             oper == Operator.Inequality ||
2650                             oper == Operator.LessThanOrEqual ||
2651                             oper == Operator.LessThan ||
2652                             oper == Operator.GreaterThanOrEqual ||
2653                             oper == Operator.GreaterThan){
2654                                 type = TypeManager.bool_type;
2655                         }
2656
2657                         return this;
2658                 }
2659
2660                 public override Expression DoResolve (EmitContext ec)
2661                 {
2662                         if ((oper == Operator.Subtraction) && (left is ParenthesizedExpression)) {
2663                                 left = ((ParenthesizedExpression) left).Expr;
2664                                 left = left.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.Type);
2665                                 if (left == null)
2666                                         return null;
2667
2668                                 if (left.eclass == ExprClass.Type) {
2669                                         Error (75, "Casting a negative value needs to have the value in parentheses.");
2670                                         return null;
2671                                 }
2672                         } else
2673                                 left = left.Resolve (ec);
2674                         right = right.Resolve (ec);
2675
2676                         if (left == null || right == null)
2677                                 return null;
2678
2679                         eclass = ExprClass.Value;
2680
2681                         Constant rc = right as Constant;
2682                         Constant lc = left as Constant;
2683
2684                         if (rc != null & lc != null){
2685                                 Expression e = ConstantFold.BinaryFold (
2686                                         ec, oper, lc, rc, loc);
2687                                         if (e != null)
2688                                                 return e;
2689                         }
2690
2691                         return ResolveOperator (ec);
2692                 }
2693
2694                 /// <remarks>
2695                 ///   EmitBranchable is called from Statement.EmitBoolExpression in the
2696                 ///   context of a conditional bool expression.  This function will return
2697                 ///   false if it is was possible to use EmitBranchable, or true if it was.
2698                 ///
2699                 ///   The expression's code is generated, and we will generate a branch to `target'
2700                 ///   if the resulting expression value is equal to isTrue
2701                 /// </remarks>
2702                 public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
2703                 {
2704                         ILGenerator ig = ec.ig;
2705
2706                         //
2707                         // This is more complicated than it looks, but its just to avoid
2708                         // duplicated tests: basically, we allow ==, !=, >, <, >= and <=
2709                         // but on top of that we want for == and != to use a special path
2710                         // if we are comparing against null
2711                         //
2712                         if ((oper == Operator.Equality || oper == Operator.Inequality) && (left is Constant || right is Constant)) {
2713                                 bool my_on_true = oper == Operator.Inequality ? onTrue : !onTrue;
2714
2715                                 //
2716                                 // put the constant on the rhs, for simplicity
2717                                 //
2718                                 if (left is Constant) {
2719                                         Expression swap = right;
2720                                         right = left;
2721                                         left = swap;
2722                                 }
2723
2724                                 if (((Constant) right).IsZeroInteger) {
2725                                         left.Emit (ec);
2726                                         if (my_on_true)
2727                                                 ig.Emit (OpCodes.Brtrue, target);
2728                                         else
2729                                                 ig.Emit (OpCodes.Brfalse, target);
2730
2731                                         return;
2732                                 } else if (right is BoolConstant) {
2733                                         left.Emit (ec);
2734                                         if (my_on_true != ((BoolConstant) right).Value)
2735                                                 ig.Emit (OpCodes.Brtrue, target);
2736                                         else
2737                                                 ig.Emit (OpCodes.Brfalse, target);
2738
2739                                         return;
2740                                 }
2741
2742                         } else if (oper == Operator.LogicalAnd) {
2743
2744                                 if (onTrue) {
2745                                         Label tests_end = ig.DefineLabel ();
2746
2747                                         left.EmitBranchable (ec, tests_end, false);
2748                                         right.EmitBranchable (ec, target, true);
2749                                         ig.MarkLabel (tests_end);
2750                                 } else {
2751                                         left.EmitBranchable (ec, target, false);
2752                                         right.EmitBranchable (ec, target, false);
2753                                 }
2754
2755                                 return;
2756
2757                         } else if (oper == Operator.LogicalOr){
2758                                 if (onTrue) {
2759                                         left.EmitBranchable (ec, target, true);
2760                                         right.EmitBranchable (ec, target, true);
2761
2762                                 } else {
2763                                         Label tests_end = ig.DefineLabel ();
2764                                         left.EmitBranchable (ec, tests_end, true);
2765                                         right.EmitBranchable (ec, target, false);
2766                                         ig.MarkLabel (tests_end);
2767                                 }
2768
2769                                 return;
2770
2771                         } else if (!(oper == Operator.LessThan        || oper == Operator.GreaterThan ||
2772                                      oper == Operator.LessThanOrEqual || oper == Operator.GreaterThanOrEqual ||
2773                                      oper == Operator.Equality        || oper == Operator.Inequality)) {
2774                                 base.EmitBranchable (ec, target, onTrue);
2775                                 return;
2776                         }
2777
2778                         left.Emit (ec);
2779                         right.Emit (ec);
2780
2781                         Type t = left.Type;
2782                         bool isUnsigned = is_unsigned (t) || t == TypeManager.double_type || t == TypeManager.float_type;
2783
2784                         switch (oper){
2785                         case Operator.Equality:
2786                                 if (onTrue)
2787                                         ig.Emit (OpCodes.Beq, target);
2788                                 else
2789                                         ig.Emit (OpCodes.Bne_Un, target);
2790                                 break;
2791
2792                         case Operator.Inequality:
2793                                 if (onTrue)
2794                                         ig.Emit (OpCodes.Bne_Un, target);
2795                                 else
2796                                         ig.Emit (OpCodes.Beq, target);
2797                                 break;
2798
2799                         case Operator.LessThan:
2800                                 if (onTrue)
2801                                         if (isUnsigned)
2802                                                 ig.Emit (OpCodes.Blt_Un, target);
2803                                         else
2804                                                 ig.Emit (OpCodes.Blt, target);
2805                                 else
2806                                         if (isUnsigned)
2807                                                 ig.Emit (OpCodes.Bge_Un, target);
2808                                         else
2809                                                 ig.Emit (OpCodes.Bge, target);
2810                                 break;
2811
2812                         case Operator.GreaterThan:
2813                                 if (onTrue)
2814                                         if (isUnsigned)
2815                                                 ig.Emit (OpCodes.Bgt_Un, target);
2816                                         else
2817                                                 ig.Emit (OpCodes.Bgt, target);
2818                                 else
2819                                         if (isUnsigned)
2820                                                 ig.Emit (OpCodes.Ble_Un, target);
2821                                         else
2822                                                 ig.Emit (OpCodes.Ble, target);
2823                                 break;
2824
2825                         case Operator.LessThanOrEqual:
2826                                 if (onTrue)
2827                                         if (isUnsigned)
2828                                                 ig.Emit (OpCodes.Ble_Un, target);
2829                                         else
2830                                                 ig.Emit (OpCodes.Ble, target);
2831                                 else
2832                                         if (isUnsigned)
2833                                                 ig.Emit (OpCodes.Bgt_Un, target);
2834                                         else
2835                                                 ig.Emit (OpCodes.Bgt, target);
2836                                 break;
2837
2838
2839                         case Operator.GreaterThanOrEqual:
2840                                 if (onTrue)
2841                                         if (isUnsigned)
2842                                                 ig.Emit (OpCodes.Bge_Un, target);
2843                                         else
2844                                                 ig.Emit (OpCodes.Bge, target);
2845                                 else
2846                                         if (isUnsigned)
2847                                                 ig.Emit (OpCodes.Blt_Un, target);
2848                                         else
2849                                                 ig.Emit (OpCodes.Blt, target);
2850                                 break;
2851                         default:
2852                                 Console.WriteLine (oper);
2853                                 throw new Exception ("what is THAT");
2854                         }
2855                 }
2856
2857                 public override void Emit (EmitContext ec)
2858                 {
2859                         ILGenerator ig = ec.ig;
2860                         Type l = left.Type;
2861                         OpCode opcode;
2862
2863                         //
2864                         // Handle short-circuit operators differently
2865                         // than the rest
2866                         //
2867                         if (oper == Operator.LogicalAnd) {
2868                                 Label load_zero = ig.DefineLabel ();
2869                                 Label end = ig.DefineLabel ();
2870
2871                                 left.EmitBranchable (ec, load_zero, false);
2872                                 right.Emit (ec);
2873                                 ig.Emit (OpCodes.Br, end);
2874
2875                                 ig.MarkLabel (load_zero);
2876                                 ig.Emit (OpCodes.Ldc_I4_0);
2877                                 ig.MarkLabel (end);
2878                                 return;
2879                         } else if (oper == Operator.LogicalOr) {
2880                                 Label load_one = ig.DefineLabel ();
2881                                 Label end = ig.DefineLabel ();
2882
2883                                 left.EmitBranchable (ec, load_one, true);
2884                                 right.Emit (ec);
2885                                 ig.Emit (OpCodes.Br, end);
2886
2887                                 ig.MarkLabel (load_one);
2888                                 ig.Emit (OpCodes.Ldc_I4_1);
2889                                 ig.MarkLabel (end);
2890                                 return;
2891                         }
2892
2893                         left.Emit (ec);
2894                         right.Emit (ec);
2895
2896                         bool isUnsigned = is_unsigned (left.Type);
2897
2898                         switch (oper){
2899                         case Operator.Multiply:
2900                                 if (ec.CheckState){
2901                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2902                                                 opcode = OpCodes.Mul_Ovf;
2903                                         else if (isUnsigned)
2904                                                 opcode = OpCodes.Mul_Ovf_Un;
2905                                         else
2906                                                 opcode = OpCodes.Mul;
2907                                 } else
2908                                         opcode = OpCodes.Mul;
2909
2910                                 break;
2911
2912                         case Operator.Division:
2913                                 if (isUnsigned)
2914                                         opcode = OpCodes.Div_Un;
2915                                 else
2916                                         opcode = OpCodes.Div;
2917                                 break;
2918
2919                         case Operator.Modulus:
2920                                 if (isUnsigned)
2921                                         opcode = OpCodes.Rem_Un;
2922                                 else
2923                                         opcode = OpCodes.Rem;
2924                                 break;
2925
2926                         case Operator.Addition:
2927                                 if (ec.CheckState){
2928                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2929                                                 opcode = OpCodes.Add_Ovf;
2930                                         else if (isUnsigned)
2931                                                 opcode = OpCodes.Add_Ovf_Un;
2932                                         else
2933                                                 opcode = OpCodes.Add;
2934                                 } else
2935                                         opcode = OpCodes.Add;
2936                                 break;
2937
2938                         case Operator.Subtraction:
2939                                 if (ec.CheckState){
2940                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2941                                                 opcode = OpCodes.Sub_Ovf;
2942                                         else if (isUnsigned)
2943                                                 opcode = OpCodes.Sub_Ovf_Un;
2944                                         else
2945                                                 opcode = OpCodes.Sub;
2946                                 } else
2947                                         opcode = OpCodes.Sub;
2948                                 break;
2949
2950                         case Operator.RightShift:
2951                                 if (isUnsigned)
2952                                         opcode = OpCodes.Shr_Un;
2953                                 else
2954                                         opcode = OpCodes.Shr;
2955                                 break;
2956
2957                         case Operator.LeftShift:
2958                                 opcode = OpCodes.Shl;
2959                                 break;
2960
2961                         case Operator.Equality:
2962                                 opcode = OpCodes.Ceq;
2963                                 break;
2964
2965                         case Operator.Inequality:
2966                                 ig.Emit (OpCodes.Ceq);
2967                                 ig.Emit (OpCodes.Ldc_I4_0);
2968
2969                                 opcode = OpCodes.Ceq;
2970                                 break;
2971
2972                         case Operator.LessThan:
2973                                 if (isUnsigned)
2974                                         opcode = OpCodes.Clt_Un;
2975                                 else
2976                                         opcode = OpCodes.Clt;
2977                                 break;
2978
2979                         case Operator.GreaterThan:
2980                                 if (isUnsigned)
2981                                         opcode = OpCodes.Cgt_Un;
2982                                 else
2983                                         opcode = OpCodes.Cgt;
2984                                 break;
2985
2986                         case Operator.LessThanOrEqual:
2987                                 Type lt = left.Type;
2988
2989                                 if (isUnsigned || (lt == TypeManager.double_type || lt == TypeManager.float_type))
2990                                         ig.Emit (OpCodes.Cgt_Un);
2991                                 else
2992                                         ig.Emit (OpCodes.Cgt);
2993                                 ig.Emit (OpCodes.Ldc_I4_0);
2994
2995                                 opcode = OpCodes.Ceq;
2996                                 break;
2997
2998                         case Operator.GreaterThanOrEqual:
2999                                 Type le = left.Type;
3000
3001                                 if (isUnsigned || (le == TypeManager.double_type || le == TypeManager.float_type))
3002                                         ig.Emit (OpCodes.Clt_Un);
3003                                 else
3004                                         ig.Emit (OpCodes.Clt);
3005
3006                                 ig.Emit (OpCodes.Ldc_I4_0);
3007
3008                                 opcode = OpCodes.Ceq;
3009                                 break;
3010
3011                         case Operator.BitwiseOr:
3012                                 opcode = OpCodes.Or;
3013                                 break;
3014
3015                         case Operator.BitwiseAnd:
3016                                 opcode = OpCodes.And;
3017                                 break;
3018
3019                         case Operator.ExclusiveOr:
3020                                 opcode = OpCodes.Xor;
3021                                 break;
3022
3023                         default:
3024                                 throw new Exception ("This should not happen: Operator = "
3025                                                      + oper.ToString ());
3026                         }
3027
3028                         ig.Emit (opcode);
3029                 }
3030         }
3031
3032         //
3033         // Object created by Binary when the binary operator uses an method instead of being
3034         // a binary operation that maps to a CIL binary operation.
3035         //
3036         public class BinaryMethod : Expression {
3037                 public MethodBase method;
3038                 public ArrayList  Arguments;
3039
3040                 public BinaryMethod (Type t, MethodBase m, ArrayList args)
3041                 {
3042                         method = m;
3043                         Arguments = args;
3044                         type = t;
3045                         eclass = ExprClass.Value;
3046                 }
3047
3048                 public override Expression DoResolve (EmitContext ec)
3049                 {
3050                         return this;
3051                 }
3052
3053                 public override void Emit (EmitContext ec)
3054                 {
3055                         ILGenerator ig = ec.ig;
3056
3057                         if (Arguments != null)
3058                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
3059
3060                         if (method is MethodInfo)
3061                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
3062                         else
3063                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
3064                 }
3065         }
3066
3067         //
3068         // Represents the operation a + b [+ c [+ d [+ ...]]], where a is a string
3069         // b, c, d... may be strings or objects.
3070         //
3071         public class StringConcat : Expression {
3072                 ArrayList operands;
3073                 bool invalid = false;
3074
3075
3076                 public StringConcat (EmitContext ec, Location loc, Expression left, Expression right)
3077                 {
3078                         this.loc = loc;
3079                         type = TypeManager.string_type;
3080                         eclass = ExprClass.Value;
3081
3082                         operands = new ArrayList (2);
3083                         Append (ec, left);
3084                         Append (ec, right);
3085                 }
3086
3087                 public override Expression DoResolve (EmitContext ec)
3088                 {
3089                         if (invalid)
3090                                 return null;
3091
3092                         return this;
3093                 }
3094
3095                 public void Append (EmitContext ec, Expression operand)
3096                 {
3097                         //
3098                         // Constant folding
3099                         //
3100                         if (operand is StringConstant && operands.Count != 0) {
3101                                 StringConstant last_operand = operands [operands.Count - 1] as StringConstant;
3102                                 if (last_operand != null) {
3103                                         operands [operands.Count - 1] = new StringConstant (last_operand.Value + ((StringConstant) operand).Value);
3104                                         return;
3105                                 }
3106                         }
3107
3108                         //
3109                         // Conversion to object
3110                         //
3111                         if (operand.Type != TypeManager.string_type) {
3112                                 Expression no = Convert.ImplicitConversion (ec, operand, TypeManager.object_type, loc);
3113
3114                                 if (no == null) {
3115                                         Binary.Error_OperatorCannotBeApplied (loc, "+", TypeManager.string_type, operand.Type);
3116                                         invalid = true;
3117                                 }
3118                                 operand = no;
3119                         }
3120
3121                         operands.Add (operand);
3122                 }
3123
3124                 public override void Emit (EmitContext ec)
3125                 {
3126                         MethodInfo concat_method = null;
3127
3128                         //
3129                         // Are we also concating objects?
3130                         //
3131                         bool is_strings_only = true;
3132
3133                         //
3134                         // Do conversion to arguments; check for strings only
3135                         //
3136                         for (int i = 0; i < operands.Count; i ++) {
3137                                 Expression e = (Expression) operands [i];
3138                                 is_strings_only &= e.Type == TypeManager.string_type;
3139                         }
3140
3141                         for (int i = 0; i < operands.Count; i ++) {
3142                                 Expression e = (Expression) operands [i];
3143
3144                                 if (! is_strings_only && e.Type == TypeManager.string_type) {
3145                                         // need to make sure this is an object, because the EmitParams
3146                                         // method might look at the type of this expression, see it is a
3147                                         // string and emit a string [] when we want an object [];
3148
3149                                         e = Convert.ImplicitConversion (ec, e, TypeManager.object_type, loc);
3150                                 }
3151                                 operands [i] = new Argument (e, Argument.AType.Expression);
3152                         }
3153
3154                         //
3155                         // Find the right method
3156                         //
3157                         switch (operands.Count) {
3158                         case 1:
3159                                 //
3160                                 // This should not be possible, because simple constant folding
3161                                 // is taken care of in the Binary code.
3162                                 //
3163                                 throw new Exception ("how did you get here?");
3164
3165                         case 2:
3166                                 concat_method = is_strings_only ?
3167                                         TypeManager.string_concat_string_string :
3168                                         TypeManager.string_concat_object_object ;
3169                                 break;
3170                         case 3:
3171                                 concat_method = is_strings_only ?
3172                                         TypeManager.string_concat_string_string_string :
3173                                         TypeManager.string_concat_object_object_object ;
3174                                 break;
3175                         case 4:
3176                                 //
3177                                 // There is not a 4 param overlaod for object (the one that there is
3178                                 // is actually a varargs methods, and is only in corlib because it was
3179                                 // introduced there before.).
3180                                 //
3181                                 if (!is_strings_only)
3182                                         goto default;
3183
3184                                 concat_method = TypeManager.string_concat_string_string_string_string;
3185                                 break;
3186                         default:
3187                                 concat_method = is_strings_only ?
3188                                         TypeManager.string_concat_string_dot_dot_dot :
3189                                         TypeManager.string_concat_object_dot_dot_dot ;
3190                                 break;
3191                         }
3192
3193                         Invocation.EmitArguments (ec, concat_method, operands, false, null);
3194                         ec.ig.Emit (OpCodes.Call, concat_method);
3195                 }
3196         }
3197
3198         //
3199         // Object created with +/= on delegates
3200         //
3201         public class BinaryDelegate : Expression {
3202                 MethodInfo method;
3203                 ArrayList  args;
3204
3205                 public BinaryDelegate (Type t, MethodInfo mi, ArrayList args)
3206                 {
3207                         method = mi;
3208                         this.args = args;
3209                         type = t;
3210                         eclass = ExprClass.Value;
3211                 }
3212
3213                 public override Expression DoResolve (EmitContext ec)
3214                 {
3215                         return this;
3216                 }
3217
3218                 public override void Emit (EmitContext ec)
3219                 {
3220                         ILGenerator ig = ec.ig;
3221
3222                         Invocation.EmitArguments (ec, method, args, false, null);
3223
3224                         ig.Emit (OpCodes.Call, (MethodInfo) method);
3225                         ig.Emit (OpCodes.Castclass, type);
3226                 }
3227
3228                 public Expression Right {
3229                         get {
3230                                 Argument arg = (Argument) args [1];
3231                                 return arg.Expr;
3232                         }
3233                 }
3234
3235                 public bool IsAddition {
3236                         get {
3237                                 return method == TypeManager.delegate_combine_delegate_delegate;
3238                         }
3239                 }
3240         }
3241
3242         //
3243         // User-defined conditional logical operator
3244         public class ConditionalLogicalOperator : Expression {
3245                 Expression left, right;
3246                 bool is_and;
3247
3248                 public ConditionalLogicalOperator (bool is_and, Expression left, Expression right, Type t, Location loc)
3249                 {
3250                         type = t;
3251                         eclass = ExprClass.Value;
3252                         this.loc = loc;
3253                         this.left = left;
3254                         this.right = right;
3255                         this.is_and = is_and;
3256                 }
3257
3258                 protected void Error19 ()
3259                 {
3260                         Binary.Error_OperatorCannotBeApplied (loc, is_and ? "&&" : "||", type, type);
3261                 }
3262
3263                 protected void Error218 ()
3264                 {
3265                         Error (218, "The type ('" + TypeManager.CSharpName (type) + "') must contain " +
3266                                "declarations of operator true and operator false");
3267                 }
3268
3269                 Expression op_true, op_false, op;
3270                 LocalTemporary left_temp;
3271
3272                 public override Expression DoResolve (EmitContext ec)
3273                 {
3274                         MethodInfo method;
3275                         Expression operator_group;
3276
3277                         operator_group = MethodLookup (ec, type, is_and ? "op_BitwiseAnd" : "op_BitwiseOr", loc);
3278                         if (operator_group == null) {
3279                                 Error19 ();
3280                                 return null;
3281                         }
3282
3283                         left_temp = new LocalTemporary (ec, type);
3284
3285                         ArrayList arguments = new ArrayList ();
3286                         arguments.Add (new Argument (left_temp, Argument.AType.Expression));
3287                         arguments.Add (new Argument (right, Argument.AType.Expression));
3288                         method = Invocation.OverloadResolve (
3289                                 ec, (MethodGroupExpr) operator_group, arguments, false, loc)
3290                                 as MethodInfo;
3291                         if ((method == null) || (method.ReturnType != type)) {
3292                                 Error19 ();
3293                                 return null;
3294                         }
3295
3296                         op = new StaticCallExpr (method, arguments, loc);
3297
3298                         op_true = GetOperatorTrue (ec, left_temp, loc);
3299                         op_false = GetOperatorFalse (ec, left_temp, loc);
3300                         if ((op_true == null) || (op_false == null)) {
3301                                 Error218 ();
3302                                 return null;
3303                         }
3304
3305                         return this;
3306                 }
3307
3308                 public override void Emit (EmitContext ec)
3309                 {
3310                         ILGenerator ig = ec.ig;
3311                         Label false_target = ig.DefineLabel ();
3312                         Label end_target = ig.DefineLabel ();
3313
3314                         ig.Emit (OpCodes.Nop);
3315
3316                         left.Emit (ec);
3317                         left_temp.Store (ec);
3318
3319                         (is_and ? op_false : op_true).EmitBranchable (ec, false_target, false);
3320                         left_temp.Emit (ec);
3321                         ig.Emit (OpCodes.Br, end_target);
3322                         ig.MarkLabel (false_target);
3323                         op.Emit (ec);
3324                         ig.MarkLabel (end_target);
3325
3326                         ig.Emit (OpCodes.Nop);
3327                 }
3328         }
3329
3330         public class PointerArithmetic : Expression {
3331                 Expression left, right;
3332                 bool is_add;
3333
3334                 //
3335                 // We assume that `l' is always a pointer
3336                 //
3337                 public PointerArithmetic (bool is_addition, Expression l, Expression r, Type t, Location loc)
3338                 {
3339                         type = t;
3340                         this.loc = loc;
3341                         left = l;
3342                         right = r;
3343                         is_add = is_addition;
3344                 }
3345
3346                 public override Expression DoResolve (EmitContext ec)
3347                 {
3348                         eclass = ExprClass.Variable;
3349
3350                         if (left.Type == TypeManager.void_ptr_type) {
3351                                 Error (242, "The operation in question is undefined on void pointers");
3352                                 return null;
3353                         }
3354
3355                         return this;
3356                 }
3357
3358                 public override void Emit (EmitContext ec)
3359                 {
3360                         Type op_type = left.Type;
3361                         ILGenerator ig = ec.ig;
3362                         Type element = TypeManager.GetElementType (op_type);
3363                         int size = GetTypeSize (element);
3364                         Type rtype = right.Type;
3365
3366                         if (rtype.IsPointer){
3367                                 //
3368                                 // handle (pointer - pointer)
3369                                 //
3370                                 left.Emit (ec);
3371                                 right.Emit (ec);
3372                                 ig.Emit (OpCodes.Sub);
3373
3374                                 if (size != 1){
3375                                         if (size == 0)
3376                                                 ig.Emit (OpCodes.Sizeof, element);
3377                                         else
3378                                                 IntLiteral.EmitInt (ig, size);
3379                                         ig.Emit (OpCodes.Div);
3380                                 }
3381                                 ig.Emit (OpCodes.Conv_I8);
3382                         } else {
3383                                 //
3384                                 // handle + and - on (pointer op int)
3385                                 //
3386                                 left.Emit (ec);
3387                                 ig.Emit (OpCodes.Conv_I);
3388                                 right.Emit (ec);
3389                                 if (size != 1){
3390                                         if (size == 0)
3391                                                 ig.Emit (OpCodes.Sizeof, element);
3392                                         else
3393                                                 IntLiteral.EmitInt (ig, size);
3394                                         if (rtype == TypeManager.int64_type)
3395                                                 ig.Emit (OpCodes.Conv_I8);
3396                                         else if (rtype == TypeManager.uint64_type)
3397                                                 ig.Emit (OpCodes.Conv_U8);
3398                                         ig.Emit (OpCodes.Mul);
3399                                 }
3400
3401                                 if (rtype == TypeManager.int64_type || rtype == TypeManager.uint64_type)
3402                                         ig.Emit (OpCodes.Conv_I);
3403
3404                                 if (is_add)
3405                                         ig.Emit (OpCodes.Add);
3406                                 else
3407                                         ig.Emit (OpCodes.Sub);
3408                         }
3409                 }
3410         }
3411
3412         /// <summary>
3413         ///   Implements the ternary conditional operator (?:)
3414         /// </summary>
3415         public class Conditional : Expression {
3416                 Expression expr, trueExpr, falseExpr;
3417
3418                 public Conditional (Expression expr, Expression trueExpr, Expression falseExpr, Location l)
3419                 {
3420                         this.expr = expr;
3421                         this.trueExpr = trueExpr;
3422                         this.falseExpr = falseExpr;
3423                         this.loc = l;
3424                 }
3425
3426                 public Expression Expr {
3427                         get {
3428                                 return expr;
3429                         }
3430                 }
3431
3432                 public Expression TrueExpr {
3433                         get {
3434                                 return trueExpr;
3435                         }
3436                 }
3437
3438                 public Expression FalseExpr {
3439                         get {
3440                                 return falseExpr;
3441                         }
3442                 }
3443
3444                 public override Expression DoResolve (EmitContext ec)
3445                 {
3446                         expr = expr.Resolve (ec);
3447
3448                         if (expr == null)
3449                                 return null;
3450
3451                         if (expr.Type != TypeManager.bool_type){
3452                                 expr = Expression.ResolveBoolean (
3453                                         ec, expr, loc);
3454
3455                                 if (expr == null)
3456                                         return null;
3457                         }
3458
3459                         trueExpr = trueExpr.Resolve (ec);
3460                         falseExpr = falseExpr.Resolve (ec);
3461
3462                         if (trueExpr == null || falseExpr == null)
3463                                 return null;
3464
3465                         eclass = ExprClass.Value;
3466                         if (trueExpr.Type == falseExpr.Type)
3467                                 type = trueExpr.Type;
3468                         else {
3469                                 Expression conv;
3470                                 Type true_type = trueExpr.Type;
3471                                 Type false_type = falseExpr.Type;
3472
3473                                 //
3474                                 // First, if an implicit conversion exists from trueExpr
3475                                 // to falseExpr, then the result type is of type falseExpr.Type
3476                                 //
3477                                 conv = Convert.ImplicitConversion (ec, trueExpr, false_type, loc);
3478                                 if (conv != null){
3479                                         //
3480                                         // Check if both can convert implicitl to each other's type
3481                                         //
3482                                         if (Convert.ImplicitConversion (ec, falseExpr, true_type, loc) != null){
3483                                                 Error (172,
3484                                                        "Can not compute type of conditional expression " +
3485                                                        "as `" + TypeManager.CSharpName (trueExpr.Type) +
3486                                                        "' and `" + TypeManager.CSharpName (falseExpr.Type) +
3487                                                        "' convert implicitly to each other");
3488                                                 return null;
3489                                         }
3490                                         type = false_type;
3491                                         trueExpr = conv;
3492                                 } else if ((conv = Convert.ImplicitConversion(ec, falseExpr, true_type,loc))!= null){
3493                                         type = true_type;
3494                                         falseExpr = conv;
3495                                 } else {
3496                                         Error (173, "The type of the conditional expression can " +
3497                                                "not be computed because there is no implicit conversion" +
3498                                                " from `" + TypeManager.CSharpName (trueExpr.Type) + "'" +
3499                                                " and `" + TypeManager.CSharpName (falseExpr.Type) + "'");
3500                                         return null;
3501                                 }
3502                         }
3503
3504                         if (expr is BoolConstant){
3505                                 BoolConstant bc = (BoolConstant) expr;
3506
3507                                 if (bc.Value)
3508                                         return trueExpr;
3509                                 else
3510                                         return falseExpr;
3511                         }
3512
3513                         return this;
3514                 }
3515
3516                 public override void Emit (EmitContext ec)
3517                 {
3518                         ILGenerator ig = ec.ig;
3519                         Label false_target = ig.DefineLabel ();
3520                         Label end_target = ig.DefineLabel ();
3521
3522                         expr.EmitBranchable (ec, false_target, false);
3523                         trueExpr.Emit (ec);
3524                         ig.Emit (OpCodes.Br, end_target);
3525                         ig.MarkLabel (false_target);
3526                         falseExpr.Emit (ec);
3527                         ig.MarkLabel (end_target);
3528                 }
3529
3530         }
3531
3532         /// <summary>
3533         ///   Local variables
3534         /// </summary>
3535         public class LocalVariableReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
3536                 public readonly string Name;
3537                 public readonly Block Block;
3538                 LocalInfo local_info;
3539                 bool is_readonly;
3540
3541                 public LocalVariableReference (Block block, string name, Location l)
3542                 {
3543                         Block = block;
3544                         Name = name;
3545                         loc = l;
3546                         eclass = ExprClass.Variable;
3547                 }
3548
3549                 // Setting `is_readonly' to false will allow you to create a writable
3550                 // reference to a read-only variable.  This is used by foreach and using.
3551                 public LocalVariableReference (Block block, string name, Location l,
3552                                                LocalInfo local_info, bool is_readonly)
3553                         : this (block, name, l)
3554                 {
3555                         this.local_info = local_info;
3556                         this.is_readonly = is_readonly;
3557                 }
3558
3559                 public VariableInfo VariableInfo {
3560                         get { return local_info.VariableInfo; }
3561                 }
3562
3563                 public bool IsReadOnly {
3564                         get {
3565                                 return is_readonly;
3566                         }
3567                 }
3568
3569                 protected void DoResolveBase (EmitContext ec)
3570                 {
3571                         if (local_info == null) {
3572                                 local_info = Block.GetLocalInfo (Name);
3573                                 is_readonly = local_info.ReadOnly;
3574                         }
3575
3576                         type = local_info.VariableType;
3577 #if false
3578                         if (ec.InAnonymousMethod)
3579                                 Block.LiftVariable (local_info);
3580 #endif
3581                 }
3582
3583                 protected Expression DoResolve (EmitContext ec, bool is_lvalue)
3584                 {
3585                         Expression e = Block.GetConstantExpression (Name);
3586                         if (e != null) {
3587                                 local_info.Used = true;
3588                                 eclass = ExprClass.Value;
3589                                 return e.Resolve (ec);
3590                         }
3591
3592                         VariableInfo variable_info = local_info.VariableInfo;
3593                         if ((variable_info != null) && !variable_info.IsAssigned (ec, loc))
3594                                 return null;
3595
3596                         if (!is_lvalue)
3597                                 local_info.Used = true;
3598
3599                         if (local_info.LocalBuilder == null)
3600                                 return ec.RemapLocal (local_info);
3601
3602                         return this;
3603                 }
3604
3605                 public override Expression DoResolve (EmitContext ec)
3606                 {
3607                         DoResolveBase (ec);
3608
3609                         return DoResolve (ec, false);
3610                 }
3611
3612                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3613                 {
3614                         DoResolveBase (ec);
3615
3616                         VariableInfo variable_info = local_info.VariableInfo;
3617                         if (variable_info != null)
3618                                 variable_info.SetAssigned (ec);
3619
3620                         Expression e = DoResolve (ec, true);
3621
3622                         if (e == null)
3623                                 return null;
3624
3625                         if (is_readonly){
3626                                 Error (1604, "cannot assign to `" + Name + "' because it is readonly");
3627                                 return null;
3628                         }
3629
3630                         CheckObsoleteAttribute (e.Type);
3631
3632                         if (local_info.LocalBuilder == null)
3633                                 return ec.RemapLocalLValue (local_info, right_side);
3634
3635                         return this;
3636                 }
3637
3638                 public bool VerifyFixed (bool is_expression)
3639                 {
3640                         return !is_expression || local_info.IsFixed;
3641                 }
3642
3643                 public override void Emit (EmitContext ec)
3644                 {
3645                         ILGenerator ig = ec.ig;
3646
3647                         ig.Emit (OpCodes.Ldloc, local_info.LocalBuilder);
3648                 }
3649
3650                 public void Emit (EmitContext ec, bool leave_copy)
3651                 {
3652                         Emit (ec);
3653                         if (leave_copy)
3654                                 ec.ig.Emit (OpCodes.Dup);
3655                 }
3656
3657                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3658                 {
3659                         source.Emit (ec);
3660                         if (leave_copy)
3661                                 ec.ig.Emit (OpCodes.Dup);
3662                         ec.ig.Emit (OpCodes.Stloc, local_info.LocalBuilder);
3663                 }
3664
3665                 public void AddressOf (EmitContext ec, AddressOp mode)
3666                 {
3667                         ILGenerator ig = ec.ig;
3668
3669                         ig.Emit (OpCodes.Ldloca, local_info.LocalBuilder);
3670                 }
3671
3672                 public override string ToString ()
3673                 {
3674                         return String.Format ("{0} ({1}:{2})", GetType (), Name, loc);
3675                 }
3676         }
3677
3678         /// <summary>
3679         ///   This represents a reference to a parameter in the intermediate
3680         ///   representation.
3681         /// </summary>
3682         public class ParameterReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
3683                 Parameters pars;
3684                 String name;
3685                 int idx;
3686                 Block block;
3687                 VariableInfo vi;
3688                 public Parameter.Modifier mod;
3689                 public bool is_ref, is_out, prepared;
3690                 LocalTemporary temp;
3691
3692                 public ParameterReference (Parameters pars, Block block, int idx, string name, Location loc)
3693                 {
3694                         this.pars = pars;
3695                         this.block = block;
3696                         this.idx  = idx;
3697                         this.name = name;
3698                         this.loc = loc;
3699                         eclass = ExprClass.Variable;
3700                 }
3701
3702                 public VariableInfo VariableInfo {
3703                         get { return vi; }
3704                 }
3705
3706                 public bool VerifyFixed (bool is_expression)
3707                 {
3708                         return !is_expression || TypeManager.IsValueType (type);
3709                 }
3710
3711                 public bool IsAssigned (EmitContext ec, Location loc)
3712                 {
3713                         if (!ec.DoFlowAnalysis || !is_out ||
3714                             ec.CurrentBranching.IsAssigned (vi))
3715                                 return true;
3716
3717                         Report.Error (165, loc,
3718                                       "Use of unassigned parameter `" + name + "'");
3719                         return false;
3720                 }
3721
3722                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
3723                 {
3724                         if (!ec.DoFlowAnalysis || !is_out ||
3725                             ec.CurrentBranching.IsFieldAssigned (vi, field_name))
3726                                 return true;
3727
3728                         Report.Error (170, loc,
3729                                       "Use of possibly unassigned field `" + field_name + "'");
3730                         return false;
3731                 }
3732
3733                 public void SetAssigned (EmitContext ec)
3734                 {
3735                         if (is_out && ec.DoFlowAnalysis)
3736                                 ec.CurrentBranching.SetAssigned (vi);
3737                 }
3738
3739                 public void SetFieldAssigned (EmitContext ec, string field_name)
3740                 {
3741                         if (is_out && ec.DoFlowAnalysis)
3742                                 ec.CurrentBranching.SetFieldAssigned (vi, field_name);
3743                 }
3744
3745                 protected void DoResolveBase (EmitContext ec)
3746                 {
3747                         type = pars.GetParameterInfo (ec.DeclSpace, idx, out mod);
3748                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3749                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3750                         eclass = ExprClass.Variable;
3751
3752                         if (is_out)
3753                                 vi = block.ParameterMap [idx];
3754                 }
3755
3756                 //
3757                 // Notice that for ref/out parameters, the type exposed is not the
3758                 // same type exposed externally.
3759                 //
3760                 // for "ref int a":
3761                 //   externally we expose "int&"
3762                 //   here we expose       "int".
3763                 //
3764                 // We record this in "is_ref".  This means that the type system can treat
3765                 // the type as it is expected, but when we generate the code, we generate
3766                 // the alternate kind of code.
3767                 //
3768                 public override Expression DoResolve (EmitContext ec)
3769                 {
3770                         DoResolveBase (ec);
3771
3772                         if (is_out && ec.DoFlowAnalysis && !IsAssigned (ec, loc))
3773                                 return null;
3774
3775                         if (ec.RemapToProxy)
3776                                 return ec.RemapParameter (idx);
3777
3778                         return this;
3779                 }
3780
3781                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3782                 {
3783                         DoResolveBase (ec);
3784
3785                         SetAssigned (ec);
3786
3787                         if (ec.RemapToProxy)
3788                                 return ec.RemapParameterLValue (idx, right_side);
3789
3790                         return this;
3791                 }
3792
3793                 static public void EmitLdArg (ILGenerator ig, int x)
3794                 {
3795                         if (x <= 255){
3796                                 switch (x){
3797                                 case 0: ig.Emit (OpCodes.Ldarg_0); break;
3798                                 case 1: ig.Emit (OpCodes.Ldarg_1); break;
3799                                 case 2: ig.Emit (OpCodes.Ldarg_2); break;
3800                                 case 3: ig.Emit (OpCodes.Ldarg_3); break;
3801                                 default: ig.Emit (OpCodes.Ldarg_S, (byte) x); break;
3802                                 }
3803                         } else
3804                                 ig.Emit (OpCodes.Ldarg, x);
3805                 }
3806
3807                 //
3808                 // This method is used by parameters that are references, that are
3809                 // being passed as references:  we only want to pass the pointer (that
3810                 // is already stored in the parameter, not the address of the pointer,
3811                 // and not the value of the variable).
3812                 //
3813                 public void EmitLoad (EmitContext ec)
3814                 {
3815                         ILGenerator ig = ec.ig;
3816                         int arg_idx = idx;
3817
3818                         if (!ec.IsStatic)
3819                                 arg_idx++;
3820
3821                         EmitLdArg (ig, arg_idx);
3822                 }
3823
3824                 public override void Emit (EmitContext ec)
3825                 {
3826                         Emit (ec, false);
3827                 }
3828
3829                 public void Emit (EmitContext ec, bool leave_copy)
3830                 {
3831                         ILGenerator ig = ec.ig;
3832
3833                         int arg_idx = idx;
3834
3835                         if (!ec.IsStatic)
3836                                 arg_idx++;
3837
3838                         EmitLdArg (ig, arg_idx);
3839
3840                         if (is_ref) {
3841                                 if (prepared)
3842                                         ec.ig.Emit (OpCodes.Dup);
3843
3844                                 //
3845                                 // If we are a reference, we loaded on the stack a pointer
3846                                 // Now lets load the real value
3847                                 //
3848                                 LoadFromPtr (ig, type);
3849                         }
3850
3851                         if (leave_copy) {
3852                                 ec.ig.Emit (OpCodes.Dup);
3853
3854                                 if (is_ref) {
3855                                         temp = new LocalTemporary (ec, type);
3856                                         temp.Store (ec);
3857                                 }
3858                         }
3859                 }
3860
3861                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3862                 {
3863                         ILGenerator ig = ec.ig;
3864                         int arg_idx = idx;
3865
3866                         prepared = prepare_for_load;
3867
3868                         if (!ec.IsStatic)
3869                                 arg_idx++;
3870
3871                         if (is_ref && !prepared)
3872                                 EmitLdArg (ig, arg_idx);
3873
3874                         source.Emit (ec);
3875
3876                         if (leave_copy)
3877                                 ec.ig.Emit (OpCodes.Dup);
3878
3879                         if (is_ref) {
3880                                 if (leave_copy) {
3881                                         temp = new LocalTemporary (ec, type);
3882                                         temp.Store (ec);
3883                                 }
3884
3885                                 StoreFromPtr (ig, type);
3886
3887                                 if (temp != null)
3888                                         temp.Emit (ec);
3889                         } else {
3890                                 if (arg_idx <= 255)
3891                                         ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
3892                                 else
3893                                         ig.Emit (OpCodes.Starg, arg_idx);
3894                         }
3895                 }
3896
3897                 public void AddressOf (EmitContext ec, AddressOp mode)
3898                 {
3899                         int arg_idx = idx;
3900
3901                         if (!ec.IsStatic)
3902                                 arg_idx++;
3903
3904                         if (is_ref){
3905                                 if (arg_idx <= 255)
3906                                         ec.ig.Emit (OpCodes.Ldarg_S, (byte) arg_idx);
3907                                 else
3908                                         ec.ig.Emit (OpCodes.Ldarg, arg_idx);
3909                         } else {
3910                                 if (arg_idx <= 255)
3911                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
3912                                 else
3913                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
3914                         }
3915                 }
3916
3917         }
3918
3919         /// <summary>
3920         ///   Used for arguments to New(), Invocation()
3921         /// </summary>
3922         public class Argument {
3923                 public enum AType : byte {
3924                         Expression,
3925                         Ref,
3926                         Out,
3927                         ArgList
3928                 };
3929
3930                 public readonly AType ArgType;
3931                 public Expression Expr;
3932
3933                 public Argument (Expression expr, AType type)
3934                 {
3935                         this.Expr = expr;
3936                         this.ArgType = type;
3937                 }
3938
3939                 public Argument (Expression expr)
3940                 {
3941                         this.Expr = expr;
3942                         this.ArgType = AType.Expression;
3943                 }
3944
3945                 public Type Type {
3946                         get {
3947                                 if (ArgType == AType.Ref || ArgType == AType.Out)
3948                                         return TypeManager.GetReferenceType (Expr.Type);
3949                                 else
3950                                         return Expr.Type;
3951                         }
3952                 }
3953
3954                 public Parameter.Modifier GetParameterModifier ()
3955                 {
3956                         switch (ArgType) {
3957                         case AType.Out:
3958                                 return Parameter.Modifier.OUT | Parameter.Modifier.ISBYREF;
3959
3960                         case AType.Ref:
3961                                 return Parameter.Modifier.REF | Parameter.Modifier.ISBYREF;
3962
3963                         default:
3964                                 return Parameter.Modifier.NONE;
3965                         }
3966                 }
3967
3968                 public static string FullDesc (Argument a)
3969                 {
3970                         if (a.ArgType == AType.ArgList)
3971                                 return "__arglist";
3972
3973                         return (a.ArgType == AType.Ref ? "ref " :
3974                                 (a.ArgType == AType.Out ? "out " : "")) +
3975                                 TypeManager.CSharpName (a.Expr.Type);
3976                 }
3977
3978                 public bool ResolveMethodGroup (EmitContext ec, Location loc)
3979                 {
3980                         // FIXME: csc doesn't report any error if you try to use `ref' or
3981                         //        `out' in a delegate creation expression.
3982                         Expr = Expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
3983                         if (Expr == null)
3984                                 return false;
3985
3986                         return true;
3987                 }
3988
3989                 public bool Resolve (EmitContext ec, Location loc)
3990                 {
3991                         if (ArgType == AType.Ref) {
3992                                 Expr = Expr.Resolve (ec);
3993                                 if (Expr == null)
3994                                         return false;
3995
3996                                 if (!ec.IsConstructor) {
3997                                         FieldExpr fe = Expr as FieldExpr;
3998                                         if (fe != null && fe.FieldInfo.IsInitOnly) {
3999                                                 if (fe.FieldInfo.IsStatic)
4000                                                         Report.Error (199, loc, "A static readonly field cannot be passed ref or out (except in a static constructor)");
4001                                                 else
4002                                                         Report.Error (192, loc, "A readonly field cannot be passed ref or out (except in a constructor)");
4003                                                 return false;
4004                                         }
4005                                 }
4006                                 Expr = Expr.ResolveLValue (ec, Expr);
4007                         } else if (ArgType == AType.Out)
4008                                 Expr = Expr.ResolveLValue (ec, new EmptyExpression ());
4009                         else
4010                                 Expr = Expr.Resolve (ec);
4011
4012                         if (Expr == null)
4013                                 return false;
4014
4015                         if (ArgType == AType.Expression)
4016                                 return true;
4017                         else {
4018                                 //
4019                                 // Catch errors where fields of a MarshalByRefObject are passed as ref or out
4020                                 // This is only allowed for `this'
4021                                 //
4022                                 FieldExpr fe = Expr as FieldExpr;
4023                                 if (fe != null && !fe.IsStatic){
4024                                         Expression instance = fe.InstanceExpression;
4025
4026                                         if (instance.GetType () != typeof (This)){
4027                                                 if (fe.InstanceExpression.Type.IsSubclassOf (TypeManager.mbr_type)){
4028                                                         Report.Error (197, loc,
4029                                                                       "Can not pass a type that derives from MarshalByRefObject with out or ref");
4030                                                         return false;
4031                                                 }
4032                                         }
4033                                 }
4034                         }
4035
4036                         if (Expr.eclass != ExprClass.Variable){
4037                                 //
4038                                 // We just probe to match the CSC output
4039                                 //
4040                                 if (Expr.eclass == ExprClass.PropertyAccess ||
4041                                     Expr.eclass == ExprClass.IndexerAccess){
4042                                         Report.Error (
4043                                                 206, loc,
4044                                                 "A property or indexer can not be passed as an out or ref " +
4045                                                 "parameter");
4046                                 } else {
4047                                         Report.Error (
4048                                                 1510, loc,
4049                                                 "An lvalue is required as an argument to out or ref");
4050                                 }
4051                                 return false;
4052                         }
4053
4054                         return true;
4055                 }
4056
4057                 public void Emit (EmitContext ec)
4058                 {
4059                         //
4060                         // Ref and Out parameters need to have their addresses taken.
4061                         //
4062                         // ParameterReferences might already be references, so we want
4063                         // to pass just the value
4064                         //
4065                         if (ArgType == AType.Ref || ArgType == AType.Out){
4066                                 AddressOp mode = AddressOp.Store;
4067
4068                                 if (ArgType == AType.Ref)
4069                                         mode |= AddressOp.Load;
4070
4071                                 if (Expr is ParameterReference){
4072                                         ParameterReference pr = (ParameterReference) Expr;
4073
4074                                         if (pr.is_ref)
4075                                                 pr.EmitLoad (ec);
4076                                         else {
4077
4078                                                 pr.AddressOf (ec, mode);
4079                                         }
4080                                 } else {
4081                                         ((IMemoryLocation)Expr).AddressOf (ec, mode);
4082                                 }
4083                         } else
4084                                 Expr.Emit (ec);
4085                 }
4086         }
4087
4088         /// <summary>
4089         ///   Invocation of methods or delegates.
4090         /// </summary>
4091         public class Invocation : ExpressionStatement {
4092                 public readonly ArrayList Arguments;
4093
4094                 Expression expr;
4095                 MethodBase method = null;
4096                 bool is_base;
4097
4098                 static Hashtable method_parameter_cache;
4099
4100                 static Invocation ()
4101                 {
4102                         method_parameter_cache = new PtrHashtable ();
4103                 }
4104
4105                 //
4106                 // arguments is an ArrayList, but we do not want to typecast,
4107                 // as it might be null.
4108                 //
4109                 // FIXME: only allow expr to be a method invocation or a
4110                 // delegate invocation (7.5.5)
4111                 //
4112                 public Invocation (Expression expr, ArrayList arguments, Location l)
4113                 {
4114                         this.expr = expr;
4115                         Arguments = arguments;
4116                         loc = l;
4117                 }
4118
4119                 public Expression Expr {
4120                         get {
4121                                 return expr;
4122                         }
4123                 }
4124
4125                 /// <summary>
4126                 ///   Returns the Parameters (a ParameterData interface) for the
4127                 ///   Method `mb'
4128                 /// </summary>
4129                 public static ParameterData GetParameterData (MethodBase mb)
4130                 {
4131                         object pd = method_parameter_cache [mb];
4132                         object ip;
4133
4134                         if (pd != null)
4135                                 return (ParameterData) pd;
4136
4137
4138                         ip = TypeManager.LookupParametersByBuilder (mb);
4139                         if (ip != null){
4140                                 method_parameter_cache [mb] = ip;
4141
4142                                 return (ParameterData) ip;
4143                         } else {
4144                                 ReflectionParameters rp = new ReflectionParameters (mb);
4145                                 method_parameter_cache [mb] = rp;
4146
4147                                 return (ParameterData) rp;
4148                         }
4149                 }
4150
4151                 /// <summary>
4152                 ///   Determines "better conversion" as specified in 7.4.2.3
4153                 ///
4154                 ///    Returns : 1 if a->p is better
4155                 ///              0 if a->q or neither is better
4156                 /// </summary>
4157                 static int BetterConversion (EmitContext ec, Argument a, Type p, Type q, Location loc)
4158                 {
4159                         Type argument_type = a.Type;
4160                         Expression argument_expr = a.Expr;
4161
4162                         if (argument_type == null)
4163                                 throw new Exception ("Expression of type " + a.Expr +
4164                                                      " does not resolve its type");
4165
4166                         if (p == null || q == null)
4167                                 throw new InternalErrorException ("BetterConversion Got a null conversion");
4168
4169                         //
4170                         // This is a special case since csc behaves this way.
4171                         //
4172                         if (argument_expr is NullLiteral &&
4173                             p == TypeManager.string_type &&
4174                             q == TypeManager.object_type)
4175                                 return 1;
4176                         else if (argument_expr is NullLiteral &&
4177                                  p == TypeManager.object_type &&
4178                                  q == TypeManager.string_type)
4179                                 return 0;
4180
4181                         //
4182                         // csc behaves this way so we emulate it. Basically, if the argument
4183                         // is null and one of the types to compare is 'object' and the other
4184                         // is a reference type, we prefer the other.
4185                         //
4186                         // I can't find this anywhere in the spec but we can interpret this
4187                         // to mean that null can be of any type you wish in such a context
4188                         //
4189                         if (argument_expr is NullLiteral &&
4190                             !p.IsValueType &&
4191                             q == TypeManager.object_type)
4192                                 return 1;
4193                         else if (argument_expr is NullLiteral &&
4194                                  !q.IsValueType &&
4195                                  p == TypeManager.object_type)
4196                                 return 0;
4197
4198
4199                         if (p == q)
4200                                 return 0;
4201
4202                         if (argument_type == p)
4203                                 return 1;
4204
4205                         if (argument_type == q)
4206                                 return 0;
4207
4208                         Expression p_tmp = new EmptyExpression (p);
4209                         Expression q_tmp = new EmptyExpression (q);
4210
4211                         if (Convert.ImplicitConversionExists (ec, p_tmp, q) == true &&
4212                             Convert.ImplicitConversionExists (ec, q_tmp, p) == false)
4213                                 return 1;
4214
4215                         if (p == TypeManager.sbyte_type)
4216                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
4217                                     q == TypeManager.uint32_type || q == TypeManager.uint64_type)
4218                                         return 1;
4219
4220                         if (p == TypeManager.short_type)
4221                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
4222                                     q == TypeManager.uint64_type)
4223                                         return 1;
4224
4225                         if (p == TypeManager.int32_type)
4226                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
4227                                         return 1;
4228
4229                         if (p == TypeManager.int64_type)
4230                                 if (q == TypeManager.uint64_type)
4231                                         return 1;
4232
4233                         return 0;
4234                 }
4235
4236                 /// <summary>
4237                 ///   Determines "Better function" between candidate
4238                 ///   and the current best match
4239                 /// </summary>
4240                 /// <remarks>
4241                 ///    Returns an integer indicating :
4242                 ///     0 if candidate ain't better
4243                 ///     1 if candidate is better than the current best match
4244                 /// </remarks>
4245                 static int BetterFunction (EmitContext ec, ArrayList args, int argument_count,
4246                                            MethodBase candidate, bool candidate_params,
4247                                            MethodBase best, bool best_params, Location loc)
4248                 {
4249                         ParameterData candidate_pd = GetParameterData (candidate);
4250                         ParameterData best_pd = GetParameterData (best);
4251
4252                         int cand_count = candidate_pd.Count;
4253
4254                         //
4255                         // If there is no best method, than this one
4256                         // is better, however, if we already found a
4257                         // best method, we cant tell. This happens
4258                         // if we have:
4259                         //
4260                         //      interface IFoo {
4261                         //              void DoIt ();
4262                         //      }
4263                         //
4264                         //      interface IBar {
4265                         //              void DoIt ();
4266                         //      }
4267                         //
4268                         //      interface IFooBar : IFoo, IBar {}
4269                         //
4270                         // We cant tell if IFoo.DoIt is better than IBar.DoIt
4271                         //
4272                         // However, we have to consider that
4273                         // Trim (); is better than Trim (params char[] chars);
4274                         //
4275                         if (cand_count == 0 && argument_count == 0)
4276                                 return best_params ? 1 : 0;
4277
4278                         if ((candidate_pd.ParameterModifier (cand_count - 1) != Parameter.Modifier.PARAMS) &&
4279                             (candidate_pd.ParameterModifier (cand_count - 1) != Parameter.Modifier.ARGLIST))
4280                                 if (cand_count != argument_count)
4281                                         return 0;
4282
4283
4284                         int rating1 = 0, rating2 = 0;
4285
4286                         for (int j = 0; j < argument_count; ++j) {
4287                                 int x, y;
4288
4289                                 Argument a = (Argument) args [j];
4290
4291                                 Type ct = candidate_pd.ParameterType (j);
4292                                 Type bt = best_pd.ParameterType (j);
4293
4294                                 if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
4295                                         if (candidate_params)
4296                                                 ct = TypeManager.GetElementType (ct);
4297
4298                                 if (best_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
4299                                         if (best_params)
4300                                                 bt = TypeManager.GetElementType (bt);
4301
4302                                 x = BetterConversion (ec, a, ct, bt, loc);
4303                                 y = BetterConversion (ec, a, bt, ct, loc);
4304
4305                                 if (x < y)
4306                                         return 0;
4307
4308                                 rating1 += x;
4309                                 rating2 += y;
4310                         }
4311
4312                         //
4313                         // If a method (in the normal form) with the
4314                         // same signature as the expanded form of the
4315                         // current best params method already exists,
4316                         // the expanded form is not applicable so we
4317                         // force it to select the candidate
4318                         //
4319                         if (!candidate_params && best_params && cand_count == argument_count)
4320                                 return 1;
4321
4322                         if (rating1 > rating2)
4323                                 return 1;
4324                         else
4325                                 return 0;
4326                 }
4327
4328                 public static string FullMethodDesc (MethodBase mb)
4329                 {
4330                         string ret_type = "";
4331
4332                         if (mb == null)
4333                                 return "";
4334
4335                         if (mb is MethodInfo)
4336                                 ret_type = TypeManager.CSharpName (((MethodInfo) mb).ReturnType);
4337
4338                         StringBuilder sb = new StringBuilder (ret_type);
4339                         sb.Append (" ");
4340                         sb.Append (mb.ReflectedType.ToString ());
4341                         sb.Append (".");
4342                         sb.Append (mb.Name);
4343
4344                         ParameterData pd = GetParameterData (mb);
4345
4346                         int count = pd.Count;
4347                         sb.Append (" (");
4348
4349                         for (int i = count; i > 0; ) {
4350                                 i--;
4351
4352                                 sb.Append (pd.ParameterDesc (count - i - 1));
4353                                 if (i != 0)
4354                                         sb.Append (", ");
4355                         }
4356
4357                         sb.Append (")");
4358                         return sb.ToString ();
4359                 }
4360
4361                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
4362                 {
4363                         MemberInfo [] miset;
4364                         MethodGroupExpr union;
4365
4366                         if (mg1 == null) {
4367                                 if (mg2 == null)
4368                                         return null;
4369                                 return (MethodGroupExpr) mg2;
4370                         } else {
4371                                 if (mg2 == null)
4372                                         return (MethodGroupExpr) mg1;
4373                         }
4374
4375                         MethodGroupExpr left_set = null, right_set = null;
4376                         int length1 = 0, length2 = 0;
4377
4378                         left_set = (MethodGroupExpr) mg1;
4379                         length1 = left_set.Methods.Length;
4380
4381                         right_set = (MethodGroupExpr) mg2;
4382                         length2 = right_set.Methods.Length;
4383
4384                         ArrayList common = new ArrayList ();
4385
4386                         foreach (MethodBase r in right_set.Methods){
4387                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
4388                                         common.Add (r);
4389                         }
4390
4391                         miset = new MemberInfo [length1 + length2 - common.Count];
4392                         left_set.Methods.CopyTo (miset, 0);
4393
4394                         int k = length1;
4395
4396                         foreach (MethodBase r in right_set.Methods) {
4397                                 if (!common.Contains (r))
4398                                         miset [k++] = r;
4399                         }
4400
4401                         union = new MethodGroupExpr (miset, loc);
4402
4403                         return union;
4404                 }
4405
4406                 static bool IsParamsMethodApplicable (EmitContext ec, MethodGroupExpr me,
4407                                                       ArrayList arguments, int arg_count,
4408                                                       ref MethodBase candidate)
4409                 {
4410                         return IsParamsMethodApplicable (
4411                                 ec, me, arguments, arg_count, false, ref candidate) ||
4412                                 IsParamsMethodApplicable (
4413                                         ec, me, arguments, arg_count, true, ref candidate);
4414
4415
4416                 }
4417
4418                 static bool IsParamsMethodApplicable (EmitContext ec, MethodGroupExpr me,
4419                                                       ArrayList arguments, int arg_count,
4420                                                       bool do_varargs, ref MethodBase candidate)
4421                 {
4422                         return IsParamsMethodApplicable (
4423                                 ec, arguments, arg_count, candidate, do_varargs);
4424                 }
4425
4426                 /// <summary>
4427                 ///   Determines if the candidate method, if a params method, is applicable
4428                 ///   in its expanded form to the given set of arguments
4429                 /// </summary>
4430                 static bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments,
4431                                                       int arg_count, MethodBase candidate,
4432                                                       bool do_varargs)
4433                 {
4434                         ParameterData pd = GetParameterData (candidate);
4435
4436                         int pd_count = pd.Count;
4437                         if (pd_count == 0)
4438                                 return false;
4439
4440                         int count = pd_count - 1;
4441                         if (do_varargs) {
4442                                 if (pd.ParameterModifier (count) != Parameter.Modifier.ARGLIST)
4443                                         return false;
4444                                 if (pd_count != arg_count)
4445                                         return false;
4446                         } else {
4447                                 if (pd.ParameterModifier (count) != Parameter.Modifier.PARAMS)
4448                                         return false;
4449                         }
4450
4451                         if (count > arg_count)
4452                                 return false;
4453
4454                         if (pd_count == 1 && arg_count == 0)
4455                                 return true;
4456
4457                         //
4458                         // If we have come this far, the case which
4459                         // remains is when the number of parameters is
4460                         // less than or equal to the argument count.
4461                         //
4462                         for (int i = 0; i < count; ++i) {
4463
4464                                 Argument a = (Argument) arguments [i];
4465
4466                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
4467                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
4468                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
4469                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
4470
4471                                 if (a_mod == p_mod) {
4472
4473                                         if (a_mod == Parameter.Modifier.NONE)
4474                                                 if (!Convert.ImplicitConversionExists (ec,
4475                                                                                        a.Expr,
4476                                                                                        pd.ParameterType (i)))
4477                                                         return false;
4478
4479                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
4480                                                 Type pt = pd.ParameterType (i);
4481
4482                                                 if (!pt.IsByRef)
4483                                                         pt = TypeManager.GetReferenceType (pt);
4484
4485                                                 if (pt != a.Type)
4486                                                         return false;
4487                                         }
4488                                 } else
4489                                         return false;
4490
4491                         }
4492
4493                         if (do_varargs) {
4494                                 Argument a = (Argument) arguments [count];
4495                                 if (!(a.Expr is Arglist))
4496                                         return false;
4497
4498                                 return true;
4499                         }
4500
4501                         Type element_type = TypeManager.GetElementType (pd.ParameterType (pd_count - 1));
4502
4503                         for (int i = pd_count - 1; i < arg_count; i++) {
4504                                 Argument a = (Argument) arguments [i];
4505
4506                                 if (!Convert.ImplicitConversionExists (ec, a.Expr, element_type))
4507                                         return false;
4508                         }
4509
4510                         return true;
4511                 }
4512
4513                 static bool IsApplicable (EmitContext ec, MethodGroupExpr me,
4514                                           ArrayList arguments, int arg_count,
4515                                           ref MethodBase candidate)
4516                 {
4517                         return IsApplicable (ec, arguments, arg_count, candidate);
4518                 }
4519
4520                 /// <summary>
4521                 ///   Determines if the candidate method is applicable (section 14.4.2.1)
4522                 ///   to the given set of arguments
4523                 /// </summary>
4524                 static bool IsApplicable (EmitContext ec, ArrayList arguments, int arg_count,
4525                                           MethodBase candidate)
4526                 {
4527                         ParameterData pd = GetParameterData (candidate);
4528
4529                         if (arg_count != pd.Count)
4530                                 return false;
4531
4532                         for (int i = arg_count; i > 0; ) {
4533                                 i--;
4534
4535                                 Argument a = (Argument) arguments [i];
4536
4537                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
4538                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
4539                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
4540                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
4541
4542
4543                                 if (a_mod == p_mod ||
4544                                     (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
4545                                         if (a_mod == Parameter.Modifier.NONE) {
4546                                                 if (!Convert.ImplicitConversionExists (ec,
4547                                                                                        a.Expr,
4548                                                                                        pd.ParameterType (i)))
4549                                                         return false;
4550                                         }
4551
4552                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
4553                                                 Type pt = pd.ParameterType (i);
4554
4555                                                 if (!pt.IsByRef)
4556                                                         pt = TypeManager.GetReferenceType (pt);
4557
4558                                                 if (pt != a.Type)
4559                                                         return false;
4560                                         }
4561                                 } else
4562                                         return false;
4563                         }
4564
4565                         return true;
4566                 }
4567
4568                 static private bool IsAncestralType (Type first_type, Type second_type)
4569                 {
4570                         return first_type != second_type &&
4571                                 (second_type.IsSubclassOf (first_type) ||
4572                                  TypeManager.ImplementsInterface (second_type, first_type));
4573                 }
4574
4575                 /// <summary>
4576                 ///   Find the Applicable Function Members (7.4.2.1)
4577                 ///
4578                 ///   me: Method Group expression with the members to select.
4579                 ///       it might contain constructors or methods (or anything
4580                 ///       that maps to a method).
4581                 ///
4582                 ///   Arguments: ArrayList containing resolved Argument objects.
4583                 ///
4584                 ///   loc: The location if we want an error to be reported, or a Null
4585                 ///        location for "probing" purposes.
4586                 ///
4587                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4588                 ///            that is the best match of me on Arguments.
4589                 ///
4590                 /// </summary>
4591                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
4592                                                           ArrayList Arguments, bool may_fail,
4593                                                           Location loc)
4594                 {
4595                         MethodBase method = null;
4596                         bool method_params = false;
4597                         Type applicable_type = null;
4598                         int arg_count = 0;
4599                         ArrayList candidates = new ArrayList ();
4600
4601                         //
4602                         // Used to keep a map between the candidate
4603                         // and whether it is being considered in its
4604                         // normal or expanded form
4605                         //
4606                         // false is normal form, true is expanded form
4607                         //
4608                         Hashtable candidate_to_form = null;
4609
4610                         if (Arguments != null)
4611                                 arg_count = Arguments.Count;
4612
4613                         if ((me.Name == "Invoke") &&
4614                             TypeManager.IsDelegateType (me.DeclaringType)) {
4615                                 Error_InvokeOnDelegate (loc);
4616                                 return null;
4617                         }
4618
4619                         MethodBase[] methods = me.Methods;
4620
4621                         //
4622                         // First we construct the set of applicable methods
4623                         //
4624                         bool is_sorted = true;
4625                         for (int i = 0; i < methods.Length; i++){
4626                                 Type decl_type = methods [i].DeclaringType;
4627
4628                                 //
4629                                 // If we have already found an applicable method
4630                                 // we eliminate all base types (Section 14.5.5.1)
4631                                 //
4632                                 if ((applicable_type != null) &&
4633                                     IsAncestralType (decl_type, applicable_type))
4634                                         continue;
4635
4636                                 //
4637                                 // Check if candidate is applicable (section 14.4.2.1)
4638                                 //   Is candidate applicable in normal form?
4639                                 //
4640                                 bool is_applicable = IsApplicable (
4641                                         ec, me, Arguments, arg_count, ref methods [i]);
4642
4643                                 if (!is_applicable &&
4644                                     (IsParamsMethodApplicable (
4645                                             ec, me, Arguments, arg_count, ref methods [i]))) {
4646                                         MethodBase candidate = methods [i];
4647                                         if (candidate_to_form == null)
4648                                                 candidate_to_form = new PtrHashtable ();
4649                                         candidate_to_form [candidate] = candidate;
4650                                         // Candidate is applicable in expanded form
4651                                         is_applicable = true;
4652                                 }
4653
4654                                 if (!is_applicable)
4655                                         continue;
4656
4657                                 candidates.Add (methods [i]);
4658
4659                                 if (applicable_type == null)
4660                                         applicable_type = decl_type;
4661                                 else if (applicable_type != decl_type) {
4662                                         is_sorted = false;
4663                                         if (IsAncestralType (applicable_type, decl_type))
4664                                                 applicable_type = decl_type;
4665                                 }
4666                         }
4667
4668                         int candidate_top = candidates.Count;
4669
4670                         if (candidate_top == 0) {
4671                                 //
4672                                 // Okay so we have failed to find anything so we
4673                                 // return by providing info about the closest match
4674                                 //
4675                                 for (int i = 0; i < methods.Length; ++i) {
4676                                         MethodBase c = (MethodBase) methods [i];
4677                                         ParameterData pd = GetParameterData (c);
4678
4679                                         if (pd.Count != arg_count)
4680                                                 continue;
4681
4682                                         VerifyArgumentsCompat (ec, Arguments, arg_count,
4683                                                                c, false, null, may_fail, loc);
4684                                         break;
4685                                 }
4686
4687                                 if (!may_fail) {
4688                                         string report_name = me.Name;
4689                                         if (report_name == ".ctor")
4690                                                 report_name = me.DeclaringType.ToString ();
4691
4692                                         Error_WrongNumArguments (
4693                                                 loc, report_name, arg_count);
4694                                         return null;
4695                                 }
4696
4697                                 return null;
4698                         }
4699
4700                         if (!is_sorted) {
4701                                 //
4702                                 // At this point, applicable_type is _one_ of the most derived types
4703                                 // in the set of types containing the methods in this MethodGroup.
4704                                 // Filter the candidates so that they only contain methods from the
4705                                 // most derived types.
4706                                 //
4707
4708                                 int finalized = 0; // Number of finalized candidates
4709
4710                                 do {
4711                                         // Invariant: applicable_type is a most derived type
4712
4713                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4714                                         // eliminating all it's base types.  At the same time, we'll also move
4715                                         // every unrelated type to the end of the array, and pick the next
4716                                         // 'applicable_type'.
4717
4718                                         Type next_applicable_type = null;
4719                                         int j = finalized; // where to put the next finalized candidate
4720                                         int k = finalized; // where to put the next undiscarded candidate
4721                                         for (int i = finalized; i < candidate_top; ++i) {
4722                                                 Type decl_type = ((MethodBase) candidates[i]).DeclaringType;
4723
4724                                                 if (decl_type == applicable_type) {
4725                                                         candidates[k++] = candidates[j];
4726                                                         candidates[j++] = candidates[i];
4727                                                         continue;
4728                                                 }
4729
4730                                                 if (IsAncestralType (decl_type, applicable_type))
4731                                                         continue;
4732
4733                                                 if (next_applicable_type != null &&
4734                                                     IsAncestralType (decl_type, next_applicable_type))
4735                                                         continue;
4736
4737                                                 candidates[k++] = candidates[i];
4738
4739                                                 if (next_applicable_type == null ||
4740                                                     IsAncestralType (next_applicable_type, decl_type))
4741                                                         next_applicable_type = decl_type;
4742                                         }
4743
4744                                         applicable_type = next_applicable_type;
4745                                         finalized = j;
4746                                         candidate_top = k;
4747                                 } while (applicable_type != null);
4748                         }
4749
4750                         //
4751                         // Now we actually find the best method
4752                         //
4753
4754                         method = (MethodBase) candidates[0];
4755                         method_params = candidate_to_form != null && candidate_to_form.Contains (method);
4756                         for (int ix = 1; ix < candidate_top; ix++){
4757                                 MethodBase candidate = (MethodBase) candidates [ix];
4758                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4759
4760                                 if (BetterFunction (ec, Arguments, arg_count,
4761                                                     candidate, cand_params,
4762                                                     method, method_params, loc) != 0) {
4763                                         method = candidate;
4764                                         method_params = cand_params;
4765                                 }
4766                         }
4767
4768                         //
4769                         // Now check that there are no ambiguities i.e the selected method
4770                         // should be better than all the others
4771                         //
4772                         bool ambiguous = false;
4773                         for (int ix = 0; ix < candidate_top; ix++){
4774                                 MethodBase candidate = (MethodBase) candidates [ix];
4775
4776                                 if (candidate == method)
4777                                         continue;
4778
4779                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4780                                 if (BetterFunction (ec, Arguments, arg_count,
4781                                                     method, method_params,
4782                                                     candidate, cand_params,
4783                                                     loc) != 1) {
4784                                         Report.SymbolRelatedToPreviousError (candidate);
4785                                         ambiguous = true;
4786                                 }
4787                         }
4788
4789                         if (ambiguous) {
4790                                 Report.SymbolRelatedToPreviousError (method);
4791                                 Report.Error (121, loc, "Ambiguous call when selecting function due to implicit casts");
4792                                 return null;
4793                         }
4794
4795
4796                         //
4797                         // And now check if the arguments are all
4798                         // compatible, perform conversions if
4799                         // necessary etc. and return if everything is
4800                         // all right
4801                         //
4802                         if (!VerifyArgumentsCompat (ec, Arguments, arg_count, method,
4803                                                     method_params, null, may_fail, loc))
4804                                 return null;
4805
4806                         return method;
4807                 }
4808
4809                 static void Error_WrongNumArguments (Location loc, String name, int arg_count)
4810                 {
4811                         Report.Error (1501, loc,
4812                                       "No overload for method `" + name + "' takes `" +
4813                                       arg_count + "' arguments");
4814                 }
4815
4816                 static void Error_InvokeOnDelegate (Location loc)
4817                 {
4818                         Report.Error (1533, loc,
4819                                       "Invoke cannot be called directly on a delegate");
4820                 }
4821
4822                 static void Error_InvalidArguments (Location loc, int idx, MethodBase method,
4823                                                     Type delegate_type, string arg_sig, string par_desc)
4824                 {
4825                         if (delegate_type == null)
4826                                 Report.Error (1502, loc,
4827                                               "The best overloaded match for method '" +
4828                                               FullMethodDesc (method) +
4829                                               "' has some invalid arguments");
4830                         else
4831                                 Report.Error (1594, loc,
4832                                               "Delegate '" + delegate_type.ToString () +
4833                                               "' has some invalid arguments.");
4834                         Report.Error (1503, loc,
4835                                       String.Format ("Argument {0}: Cannot convert from '{1}' to '{2}'",
4836                                                      idx, arg_sig, par_desc));
4837                 }
4838
4839                 public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
4840                                                           int arg_count, MethodBase method,
4841                                                           bool chose_params_expanded,
4842                                                           Type delegate_type, bool may_fail,
4843                                                           Location loc)
4844                 {
4845                         ParameterData pd = GetParameterData (method);
4846                         int pd_count = pd.Count;
4847
4848                         for (int j = 0; j < arg_count; j++) {
4849                                 Argument a = (Argument) Arguments [j];
4850                                 Expression a_expr = a.Expr;
4851                                 Type parameter_type = pd.ParameterType (j);
4852                                 Parameter.Modifier pm = pd.ParameterModifier (j);
4853
4854                                 if (pm == Parameter.Modifier.PARAMS){
4855                                         if ((pm & ~Parameter.Modifier.PARAMS) != a.GetParameterModifier ()) {
4856                                                 if (!may_fail)
4857                                                         Error_InvalidArguments (
4858                                                                 loc, j, method, delegate_type,
4859                                                                 Argument.FullDesc (a), pd.ParameterDesc (j));
4860                                                 return false;
4861                                         }
4862
4863                                         if (chose_params_expanded)
4864                                                 parameter_type = TypeManager.GetElementType (parameter_type);
4865                                 } else if (pm == Parameter.Modifier.ARGLIST){
4866                                         continue;
4867                                 } else {
4868                                         //
4869                                         // Check modifiers
4870                                         //
4871                                         if (pd.ParameterModifier (j) != a.GetParameterModifier ()){
4872                                                 if (!may_fail)
4873                                                         Error_InvalidArguments (
4874                                                                 loc, j, method, delegate_type,
4875                                                                 Argument.FullDesc (a), pd.ParameterDesc (j));
4876                                                 return false;
4877                                         }
4878                                 }
4879
4880                                 //
4881                                 // Check Type
4882                                 //
4883                                 if (!a.Type.Equals (parameter_type)){
4884                                         Expression conv;
4885
4886                                         conv = Convert.ImplicitConversion (ec, a_expr, parameter_type, loc);
4887
4888                                         if (conv == null) {
4889                                                 if (!may_fail)
4890                                                         Error_InvalidArguments (
4891                                                                 loc, j, method, delegate_type,
4892                                                                 Argument.FullDesc (a), pd.ParameterDesc (j));
4893                                                 return false;
4894                                         }
4895
4896                                         //
4897                                         // Update the argument with the implicit conversion
4898                                         //
4899                                         if (a_expr != conv)
4900                                                 a.Expr = conv;
4901                                 }
4902
4903                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
4904                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
4905                                 Parameter.Modifier p_mod = pd.ParameterModifier (j) &
4906                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
4907
4908                                 if (a_mod != p_mod &&
4909                                     pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
4910                                         if (!may_fail) {
4911                                                 Report.Error (1502, loc,
4912                                                        "The best overloaded match for method '" + FullMethodDesc (method)+
4913                                                        "' has some invalid arguments");
4914                                                 Report.Error (1503, loc,
4915                                                        "Argument " + (j+1) +
4916                                                        ": Cannot convert from '" + Argument.FullDesc (a)
4917                                                        + "' to '" + pd.ParameterDesc (j) + "'");
4918                                         }
4919
4920                                         return false;
4921                                 }
4922                         }
4923
4924                         return true;
4925                 }
4926
4927                 public override Expression DoResolve (EmitContext ec)
4928                 {
4929                         //
4930                         // First, resolve the expression that is used to
4931                         // trigger the invocation
4932                         //
4933                         if (expr is BaseAccess)
4934                                 is_base = true;
4935
4936                         expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
4937                         if (expr == null)
4938                                 return null;
4939
4940                         if (!(expr is MethodGroupExpr)) {
4941                                 Type expr_type = expr.Type;
4942
4943                                 if (expr_type != null){
4944                                         bool IsDelegate = TypeManager.IsDelegateType (expr_type);
4945                                         if (IsDelegate)
4946                                                 return (new DelegateInvocation (
4947                                                         this.expr, Arguments, loc)).Resolve (ec);
4948                                 }
4949                         }
4950
4951                         if (!(expr is MethodGroupExpr)){
4952                                 expr.Error_UnexpectedKind (ResolveFlags.MethodGroup);
4953                                 return null;
4954                         }
4955
4956                         //
4957                         // Next, evaluate all the expressions in the argument list
4958                         //
4959                         if (Arguments != null){
4960                                 foreach (Argument a in Arguments){
4961                                         if (!a.Resolve (ec, loc))
4962                                                 return null;
4963                                 }
4964                         }
4965
4966                         MethodGroupExpr mg = (MethodGroupExpr) expr;
4967                         method = OverloadResolve (ec, mg, Arguments, false, loc);
4968
4969                         if (method == null)
4970                                 return null;
4971
4972                         MethodInfo mi = method as MethodInfo;
4973                         if (mi != null) {
4974                                 type = TypeManager.TypeToCoreType (mi.ReturnType);
4975                                 if (!mi.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null)) {
4976                                         SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
4977                                         return null;
4978                                 }
4979
4980                                 Expression iexpr = mg.InstanceExpression;
4981                                 if (mi.IsStatic && (iexpr != null) && !(iexpr is This)) {
4982                                         if (mg.IdenticalTypeName)
4983                                                 mg.InstanceExpression = null;
4984                                         else {
4985                                                 MemberAccess.error176 (loc, mi.Name);
4986                                                 return null;
4987                                         }
4988                                 }
4989                         }
4990
4991                         if (type.IsPointer){
4992                                 if (!ec.InUnsafe){
4993                                         UnsafeError (loc);
4994                                         return null;
4995                                 }
4996                         }
4997
4998                         //
4999                         // Only base will allow this invocation to happen.
5000                         //
5001                         if (is_base && method.IsAbstract){
5002                                 Report.Error (205, loc, "Cannot call an abstract base member: " +
5003                                               FullMethodDesc (method));
5004                                 return null;
5005                         }
5006
5007                         if ((method.Attributes & MethodAttributes.SpecialName) != 0){
5008                                 if (TypeManager.IsSpecialMethod (method))
5009                                         Report.Error (571, loc, method.Name + ": can not call operator or accessor");
5010                         }
5011
5012                         eclass = ExprClass.Value;
5013                         return this;
5014                 }
5015
5016                 // <summary>
5017                 //   Emits the list of arguments as an array
5018                 // </summary>
5019                 static void EmitParams (EmitContext ec, int idx, ArrayList arguments)
5020                 {
5021                         ILGenerator ig = ec.ig;
5022                         int count = arguments.Count - idx;
5023                         Argument a = (Argument) arguments [idx];
5024                         Type t = a.Expr.Type;
5025
5026                         IntConstant.EmitInt (ig, count);
5027                         ig.Emit (OpCodes.Newarr, TypeManager.TypeToCoreType (t));
5028
5029                         int top = arguments.Count;
5030                         for (int j = idx; j < top; j++){
5031                                 a = (Argument) arguments [j];
5032
5033                                 ig.Emit (OpCodes.Dup);
5034                                 IntConstant.EmitInt (ig, j - idx);
5035
5036                                 bool is_stobj;
5037                                 OpCode op = ArrayAccess.GetStoreOpcode (t, out is_stobj);
5038                                 if (is_stobj)
5039                                         ig.Emit (OpCodes.Ldelema, t);
5040
5041                                 a.Emit (ec);
5042
5043                                 if (is_stobj)
5044                                         ig.Emit (OpCodes.Stobj, t);
5045                                 else
5046                                         ig.Emit (op);
5047                         }
5048                 }
5049
5050                 /// <summary>
5051                 ///   Emits a list of resolved Arguments that are in the arguments
5052                 ///   ArrayList.
5053                 ///
5054                 ///   The MethodBase argument might be null if the
5055                 ///   emission of the arguments is known not to contain
5056                 ///   a `params' field (for example in constructors or other routines
5057                 ///   that keep their arguments in this structure)
5058                 ///
5059                 ///   if `dup_args' is true, a copy of the arguments will be left
5060                 ///   on the stack. If `dup_args' is true, you can specify `this_arg'
5061                 ///   which will be duplicated before any other args. Only EmitCall
5062                 ///   should be using this interface.
5063                 /// </summary>
5064                 public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments, bool dup_args, LocalTemporary this_arg)
5065                 {
5066                         ParameterData pd;
5067                         if (mb != null)
5068                                 pd = GetParameterData (mb);
5069                         else
5070                                 pd = null;
5071
5072                         LocalTemporary [] temps = null;
5073
5074                         if (dup_args)
5075                                 temps = new LocalTemporary [arguments.Count];
5076
5077                         //
5078                         // If we are calling a params method with no arguments, special case it
5079                         //
5080                         if (arguments == null){
5081                                 if (pd != null && pd.Count > 0 &&
5082                                     pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
5083                                         ILGenerator ig = ec.ig;
5084
5085                                         IntConstant.EmitInt (ig, 0);
5086                                         ig.Emit (OpCodes.Newarr, TypeManager.GetElementType (pd.ParameterType (0)));
5087                                 }
5088
5089                                 return;
5090                         }
5091
5092                         int top = arguments.Count;
5093
5094                         for (int i = 0; i < top; i++){
5095                                 Argument a = (Argument) arguments [i];
5096
5097                                 if (pd != null){
5098                                         if (pd.ParameterModifier (i) == Parameter.Modifier.PARAMS){
5099                                                 //
5100                                                 // Special case if we are passing the same data as the
5101                                                 // params argument, do not put it in an array.
5102                                                 //
5103                                                 if (pd.ParameterType (i) == a.Type)
5104                                                         a.Emit (ec);
5105                                                 else
5106                                                         EmitParams (ec, i, arguments);
5107                                                 return;
5108                                         }
5109                                 }
5110
5111                                 a.Emit (ec);
5112                                 if (dup_args) {
5113                                         ec.ig.Emit (OpCodes.Dup);
5114                                         (temps [i] = new LocalTemporary (ec, a.Type)).Store (ec);
5115                                 }
5116                         }
5117
5118                         if (dup_args) {
5119                                 if (this_arg != null)
5120                                         this_arg.Emit (ec);
5121
5122                                 for (int i = 0; i < top; i ++)
5123                                         temps [i].Emit (ec);
5124                         }
5125
5126                         if (pd != null && pd.Count > top &&
5127                             pd.ParameterModifier (top) == Parameter.Modifier.PARAMS){
5128                                 ILGenerator ig = ec.ig;
5129
5130                                 IntConstant.EmitInt (ig, 0);
5131                                 ig.Emit (OpCodes.Newarr, TypeManager.GetElementType (pd.ParameterType (top)));
5132                         }
5133                 }
5134
5135                 static Type[] GetVarargsTypes (EmitContext ec, MethodBase mb,
5136                                                ArrayList arguments)
5137                 {
5138                         ParameterData pd = GetParameterData (mb);
5139
5140                         if (arguments == null)
5141                                 return new Type [0];
5142
5143                         Argument a = (Argument) arguments [pd.Count - 1];
5144                         Arglist list = (Arglist) a.Expr;
5145
5146                         return list.ArgumentTypes;
5147                 }
5148
5149                 /// <summary>
5150                 /// This checks the ConditionalAttribute on the method
5151                 /// </summary>
5152                 static bool IsMethodExcluded (MethodBase method, EmitContext ec)
5153                 {
5154                         if (method.IsConstructor)
5155                                 return false;
5156
5157                         IMethodData md = TypeManager.GetMethod (method);
5158                         if (md != null)
5159                                 return md.IsExcluded (ec);
5160
5161                         // For some methods (generated by delegate class) GetMethod returns null
5162                         // because they are not included in builder_to_method table
5163                         if (method.DeclaringType is TypeBuilder)
5164                                 return false;
5165
5166                         return AttributeTester.IsConditionalMethodExcluded (method);
5167                 }
5168
5169                 /// <remarks>
5170                 ///   is_base tells whether we want to force the use of the `call'
5171                 ///   opcode instead of using callvirt.  Call is required to call
5172                 ///   a specific method, while callvirt will always use the most
5173                 ///   recent method in the vtable.
5174                 ///
5175                 ///   is_static tells whether this is an invocation on a static method
5176                 ///
5177                 ///   instance_expr is an expression that represents the instance
5178                 ///   it must be non-null if is_static is false.
5179                 ///
5180                 ///   method is the method to invoke.
5181                 ///
5182                 ///   Arguments is the list of arguments to pass to the method or constructor.
5183                 /// </remarks>
5184                 public static void EmitCall (EmitContext ec, bool is_base,
5185                                              bool is_static, Expression instance_expr,
5186                                              MethodBase method, ArrayList Arguments, Location loc)
5187                 {
5188                         EmitCall (ec, is_base, is_static, instance_expr, method, Arguments, loc, false, false);
5189                 }
5190
5191                 // `dup_args' leaves an extra copy of the arguments on the stack
5192                 // `omit_args' does not leave any arguments at all.
5193                 // So, basically, you could make one call with `dup_args' set to true,
5194                 // and then another with `omit_args' set to true, and the two calls
5195                 // would have the same set of arguments. However, each argument would
5196                 // only have been evaluated once.
5197                 public static void EmitCall (EmitContext ec, bool is_base,
5198                                              bool is_static, Expression instance_expr,
5199                                              MethodBase method, ArrayList Arguments, Location loc,
5200                                              bool dup_args, bool omit_args)
5201                 {
5202                         ILGenerator ig = ec.ig;
5203                         bool struct_call = false;
5204                         bool this_call = false;
5205                         LocalTemporary this_arg = null;
5206
5207                         Type decl_type = method.DeclaringType;
5208
5209                         if (!RootContext.StdLib) {
5210                                 // Replace any calls to the system's System.Array type with calls to
5211                                 // the newly created one.
5212                                 if (method == TypeManager.system_int_array_get_length)
5213                                         method = TypeManager.int_array_get_length;
5214                                 else if (method == TypeManager.system_int_array_get_rank)
5215                                         method = TypeManager.int_array_get_rank;
5216                                 else if (method == TypeManager.system_object_array_clone)
5217                                         method = TypeManager.object_array_clone;
5218                                 else if (method == TypeManager.system_int_array_get_length_int)
5219                                         method = TypeManager.int_array_get_length_int;
5220                                 else if (method == TypeManager.system_int_array_get_lower_bound_int)
5221                                         method = TypeManager.int_array_get_lower_bound_int;
5222                                 else if (method == TypeManager.system_int_array_get_upper_bound_int)
5223                                         method = TypeManager.int_array_get_upper_bound_int;
5224                                 else if (method == TypeManager.system_void_array_copyto_array_int)
5225                                         method = TypeManager.void_array_copyto_array_int;
5226                         }
5227
5228                         //
5229                         // This checks ObsoleteAttribute on the method and on the declaring type
5230                         //
5231                         ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (method);
5232                         if (oa != null)
5233                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.CSharpSignature (method), loc);
5234
5235
5236                         oa = AttributeTester.GetObsoleteAttribute (method.DeclaringType);
5237                         if (oa != null) {
5238                                 AttributeTester.Report_ObsoleteMessage (oa, method.DeclaringType.FullName, loc);
5239                         }
5240
5241                         if (IsMethodExcluded (method, ec))
5242                 return;
5243
5244                         if (!is_static){
5245                                 this_call = instance_expr == null;
5246                                 if (decl_type.IsValueType || (!this_call && instance_expr.Type.IsValueType))
5247                                         struct_call = true;
5248
5249                                 //
5250                                 // If this is ourselves, push "this"
5251                                 //
5252                                 if (!omit_args) {
5253                                 Type t = null;
5254                                 if (this_call) {
5255                                         ig.Emit (OpCodes.Ldarg_0);
5256                                         t = decl_type;
5257                                 } else {
5258                                         //
5259                                         // Push the instance expression
5260                                         //
5261                                         if (instance_expr.Type.IsValueType) {
5262                                                 //
5263                                                 // Special case: calls to a function declared in a
5264                                                 // reference-type with a value-type argument need
5265                                                 // to have their value boxed.
5266                                                 if (decl_type.IsValueType) {
5267                                                         //
5268                                                         // If the expression implements IMemoryLocation, then
5269                                                         // we can optimize and use AddressOf on the
5270                                                         // return.
5271                                                         //
5272                                                         // If not we have to use some temporary storage for
5273                                                         // it.
5274                                                         if (instance_expr is IMemoryLocation) {
5275                                                                 ((IMemoryLocation)instance_expr).
5276                                                                         AddressOf (ec, AddressOp.LoadStore);
5277                                                         } else {
5278                                                                 LocalTemporary temp = new LocalTemporary (ec, instance_expr.Type);
5279                                                                 instance_expr.Emit (ec);
5280                                                                 temp.Store (ec);
5281                                                                 temp.AddressOf (ec, AddressOp.Load);
5282                                                         }
5283
5284                                                         // avoid the overhead of doing this all the time.
5285                                                         if (dup_args)
5286                                                                 t = TypeManager.GetReferenceType (instance_expr.Type);
5287                                                 } else {
5288                                                         instance_expr.Emit (ec);
5289                                                         ig.Emit (OpCodes.Box, instance_expr.Type);
5290                                                         t = TypeManager.object_type;
5291                                                 }
5292                                         } else {
5293                                                 instance_expr.Emit (ec);
5294                                                 t = instance_expr.Type;
5295                                         }
5296                                 }
5297
5298                                 if (dup_args) {
5299                                         this_arg = new LocalTemporary (ec, t);
5300                                         ig.Emit (OpCodes.Dup);
5301                                         this_arg.Store (ec);
5302                                 }
5303                                 }
5304                         }
5305
5306                         if (!omit_args)
5307                                 EmitArguments (ec, method, Arguments, dup_args, this_arg);
5308
5309                         OpCode call_op;
5310                         if (is_static || struct_call || is_base || (this_call && !method.IsVirtual))
5311                                 call_op = OpCodes.Call;
5312                         else
5313                                 call_op = OpCodes.Callvirt;
5314
5315                         if ((method.CallingConvention & CallingConventions.VarArgs) != 0) {
5316                                 Type[] varargs_types = GetVarargsTypes (ec, method, Arguments);
5317                                 ig.EmitCall (call_op, (MethodInfo) method, varargs_types);
5318                                 return;
5319                         }
5320
5321                         //
5322                         // If you have:
5323                         // this.DoFoo ();
5324                         // and DoFoo is not virtual, you can omit the callvirt,
5325                         // because you don't need the null checking behavior.
5326                         //
5327                         if (method is MethodInfo)
5328                                 ig.Emit (call_op, (MethodInfo) method);
5329                         else
5330                                 ig.Emit (call_op, (ConstructorInfo) method);
5331                 }
5332
5333                 public override void Emit (EmitContext ec)
5334                 {
5335                         MethodGroupExpr mg = (MethodGroupExpr) this.expr;
5336
5337                         EmitCall (ec, is_base, method.IsStatic, mg.InstanceExpression, method, Arguments, loc);
5338                 }
5339
5340                 public override void EmitStatement (EmitContext ec)
5341                 {
5342                         Emit (ec);
5343
5344                         //
5345                         // Pop the return value if there is one
5346                         //
5347                         if (method is MethodInfo){
5348                                 Type ret = ((MethodInfo)method).ReturnType;
5349                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
5350                                         ec.ig.Emit (OpCodes.Pop);
5351                         }
5352                 }
5353         }
5354
5355         public class InvocationOrCast : ExpressionStatement
5356         {
5357                 Expression expr;
5358                 Expression argument;
5359
5360                 public InvocationOrCast (Expression expr, Expression argument, Location loc)
5361                 {
5362                         this.expr = expr;
5363                         this.argument = argument;
5364                         this.loc = loc;
5365                 }
5366
5367                 public override Expression DoResolve (EmitContext ec)
5368                 {
5369                         //
5370                         // First try to resolve it as a cast.
5371                         //
5372                         type = ec.DeclSpace.ResolveType (expr, true, loc);
5373                         if (type != null) {
5374                                 Cast cast = new Cast (new TypeExpression (type, loc), argument, loc);
5375                                 return cast.Resolve (ec);
5376                         }
5377
5378                         //
5379                         // This can either be a type or a delegate invocation.
5380                         // Let's just resolve it and see what we'll get.
5381                         //
5382                         expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
5383                         if (expr == null)
5384                                 return null;
5385
5386                         //
5387                         // Ok, so it's a Cast.
5388                         //
5389                         if (expr.eclass == ExprClass.Type) {
5390                                 Cast cast = new Cast (new TypeExpression (expr.Type, loc), argument, loc);
5391                                 return cast.Resolve (ec);
5392                         }
5393
5394                         //
5395                         // It's a delegate invocation.
5396                         //
5397                         if (!TypeManager.IsDelegateType (expr.Type)) {
5398                                 Error (149, "Method name expected");
5399                                 return null;
5400                         }
5401
5402                         ArrayList args = new ArrayList ();
5403                         args.Add (new Argument (argument, Argument.AType.Expression));
5404                         DelegateInvocation invocation = new DelegateInvocation (expr, args, loc);
5405                         return invocation.Resolve (ec);
5406                 }
5407
5408                 void error201 ()
5409                 {
5410                         Error (201, "Only assignment, call, increment, decrement and new object " +
5411                                "expressions can be used as a statement");
5412                 }
5413
5414                 public override ExpressionStatement ResolveStatement (EmitContext ec)
5415                 {
5416                         //
5417                         // First try to resolve it as a cast.
5418                         //
5419                         type = ec.DeclSpace.ResolveType (expr, true, loc);
5420                         if (type != null) {
5421                                 error201 ();
5422                                 return null;
5423                         }
5424
5425                         //
5426                         // This can either be a type or a delegate invocation.
5427                         // Let's just resolve it and see what we'll get.
5428                         //
5429                         expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
5430                         if ((expr == null) || (expr.eclass == ExprClass.Type)) {
5431                                 error201 ();
5432                                 return null;
5433                         }
5434
5435                         //
5436                         // It's a delegate invocation.
5437                         //
5438                         if (!TypeManager.IsDelegateType (expr.Type)) {
5439                                 Error (149, "Method name expected");
5440                                 return null;
5441                         }
5442
5443                         ArrayList args = new ArrayList ();
5444                         args.Add (new Argument (argument, Argument.AType.Expression));
5445                         DelegateInvocation invocation = new DelegateInvocation (expr, args, loc);
5446                         return invocation.ResolveStatement (ec);
5447                 }
5448
5449                 public override void Emit (EmitContext ec)
5450                 {
5451                         throw new Exception ("Cannot happen");
5452                 }
5453
5454                 public override void EmitStatement (EmitContext ec)
5455                 {
5456                         throw new Exception ("Cannot happen");
5457                 }
5458         }
5459
5460         //
5461         // This class is used to "disable" the code generation for the
5462         // temporary variable when initializing value types.
5463         //
5464         class EmptyAddressOf : EmptyExpression, IMemoryLocation {
5465                 public void AddressOf (EmitContext ec, AddressOp Mode)
5466                 {
5467                         // nothing
5468                 }
5469         }
5470
5471         /// <summary>
5472         ///    Implements the new expression
5473         /// </summary>
5474         public class New : ExpressionStatement, IMemoryLocation {
5475                 public readonly ArrayList Arguments;
5476
5477                 //
5478                 // During bootstrap, it contains the RequestedType,
5479                 // but if `type' is not null, it *might* contain a NewDelegate
5480                 // (because of field multi-initialization)
5481                 //
5482                 public Expression RequestedType;
5483
5484                 MethodBase method = null;
5485
5486                 //
5487                 // If set, the new expression is for a value_target, and
5488                 // we will not leave anything on the stack.
5489                 //
5490                 Expression value_target;
5491                 bool value_target_set = false;
5492
5493                 public New (Expression requested_type, ArrayList arguments, Location l)
5494                 {
5495                         RequestedType = requested_type;
5496                         Arguments = arguments;
5497                         loc = l;
5498                 }
5499
5500                 public bool SetValueTypeVariable (Expression value)
5501                 {
5502                         value_target = value;
5503                         value_target_set = true;
5504                         if (!(value_target is IMemoryLocation)){
5505                                 Error_UnexpectedKind ("variable");
5506                                 return false;
5507                         }
5508                         return true;
5509                 }
5510
5511                 //
5512                 // This function is used to disable the following code sequence for
5513                 // value type initialization:
5514                 //
5515                 // AddressOf (temporary)
5516                 // Construct/Init
5517                 // LoadTemporary
5518                 //
5519                 // Instead the provide will have provided us with the address on the
5520                 // stack to store the results.
5521                 //
5522                 static Expression MyEmptyExpression;
5523
5524                 public void DisableTemporaryValueType ()
5525                 {
5526                         if (MyEmptyExpression == null)
5527                                 MyEmptyExpression = new EmptyAddressOf ();
5528
5529                         //
5530                         // To enable this, look into:
5531                         // test-34 and test-89 and self bootstrapping.
5532                         //
5533                         // For instance, we can avoid a copy by using `newobj'
5534                         // instead of Call + Push-temp on value types.
5535 //                      value_target = MyEmptyExpression;
5536                 }
5537
5538                 public override Expression DoResolve (EmitContext ec)
5539                 {
5540                         //
5541                         // The New DoResolve might be called twice when initializing field
5542                         // expressions (see EmitFieldInitializers, the call to
5543                         // GetInitializerExpression will perform a resolve on the expression,
5544                         // and later the assign will trigger another resolution
5545                         //
5546                         // This leads to bugs (#37014)
5547                         //
5548                         if (type != null){
5549                                 if (RequestedType is NewDelegate)
5550                                         return RequestedType;
5551                                 return this;
5552                         }
5553
5554                         type = ec.DeclSpace.ResolveType (RequestedType, false, loc);
5555
5556                         if (type == null)
5557                                 return null;
5558
5559                         CheckObsoleteAttribute (type);
5560
5561                         bool IsDelegate = TypeManager.IsDelegateType (type);
5562
5563                         if (IsDelegate){
5564                                 RequestedType = (new NewDelegate (type, Arguments, loc)).Resolve (ec);
5565                                 if (RequestedType != null)
5566                                         if (!(RequestedType is NewDelegate))
5567                                                 throw new Exception ("NewDelegate.Resolve returned a non NewDelegate: " + RequestedType.GetType ());
5568                                 return RequestedType;
5569                         }
5570
5571                         if (type.IsAbstract && type.IsSealed) {
5572                                 Report.Error (712, loc, "Cannot create an instance of the static class '{0}'", TypeManager.CSharpName (type));
5573                                 return null;
5574                         }
5575
5576                         if (type.IsInterface || type.IsAbstract){
5577                                 Error (144, "It is not possible to create instances of interfaces or abstract classes");
5578                                 return null;
5579                         }
5580
5581                         bool is_struct = type.IsValueType;
5582                         eclass = ExprClass.Value;
5583
5584                         //
5585                         // SRE returns a match for .ctor () on structs (the object constructor),
5586                         // so we have to manually ignore it.
5587                         //
5588                         if (is_struct && Arguments == null)
5589                                 return this;
5590
5591                         Expression ml;
5592                         // For member-lookup, treat 'new Foo (bar)' as call to 'foo.ctor (bar)', where 'foo' is of type 'Foo'.
5593                         ml = MemberLookupFinal (ec, type, type, ".ctor",
5594                                                 MemberTypes.Constructor,
5595                                                 AllBindingFlags | BindingFlags.DeclaredOnly, loc);
5596
5597                         if (ml == null)
5598                                 return null;
5599
5600                         if (! (ml is MethodGroupExpr)){
5601                                 if (!is_struct){
5602                                         ml.Error_UnexpectedKind ("method group");
5603                                         return null;
5604                                 }
5605                         }
5606
5607                         if (ml != null) {
5608                                 if (Arguments != null){
5609                                         foreach (Argument a in Arguments){
5610                                                 if (!a.Resolve (ec, loc))
5611                                                         return null;
5612                                         }
5613                                 }
5614
5615                                 method = Invocation.OverloadResolve (
5616                                         ec, (MethodGroupExpr) ml, Arguments, false, loc);
5617
5618                         }
5619
5620                         if (method == null) {
5621                                 if (!is_struct || Arguments.Count > 0) {
5622                                         Error (1501, String.Format (
5623                                             "New invocation: Can not find a constructor in `{0}' for this argument list",
5624                                             TypeManager.CSharpName (type)));
5625                                         return null;
5626                                 }
5627                         }
5628
5629                         return this;
5630                 }
5631
5632                 //
5633                 // This DoEmit can be invoked in two contexts:
5634                 //    * As a mechanism that will leave a value on the stack (new object)
5635                 //    * As one that wont (init struct)
5636                 //
5637                 // You can control whether a value is required on the stack by passing
5638                 // need_value_on_stack.  The code *might* leave a value on the stack
5639                 // so it must be popped manually
5640                 //
5641                 // If we are dealing with a ValueType, we have a few
5642                 // situations to deal with:
5643                 //
5644                 //    * The target is a ValueType, and we have been provided
5645                 //      the instance (this is easy, we are being assigned).
5646                 //
5647                 //    * The target of New is being passed as an argument,
5648                 //      to a boxing operation or a function that takes a
5649                 //      ValueType.
5650                 //
5651                 //      In this case, we need to create a temporary variable
5652                 //      that is the argument of New.
5653                 //
5654                 // Returns whether a value is left on the stack
5655                 //
5656                 bool DoEmit (EmitContext ec, bool need_value_on_stack)
5657                 {
5658                         bool is_value_type = type.IsValueType;
5659                         ILGenerator ig = ec.ig;
5660
5661                         if (is_value_type){
5662                                 IMemoryLocation ml;
5663
5664                                 // Allow DoEmit() to be called multiple times.
5665                                 // We need to create a new LocalTemporary each time since
5666                                 // you can't share LocalBuilders among ILGeneators.
5667                                 if (!value_target_set)
5668                                         value_target = new LocalTemporary (ec, type);
5669
5670                                 ml = (IMemoryLocation) value_target;
5671                                 ml.AddressOf (ec, AddressOp.Store);
5672                         }
5673
5674                         if (method != null)
5675                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
5676
5677                         if (is_value_type){
5678                                 if (method == null)
5679                                         ig.Emit (OpCodes.Initobj, type);
5680                                 else
5681                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
5682                                 if (need_value_on_stack){
5683                                         value_target.Emit (ec);
5684                                         return true;
5685                                 }
5686                                 return false;
5687                         } else {
5688                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) method);
5689                                 return true;
5690                         }
5691                 }
5692
5693                 public override void Emit (EmitContext ec)
5694                 {
5695                         DoEmit (ec, true);
5696                 }
5697
5698                 public override void EmitStatement (EmitContext ec)
5699                 {
5700                         if (DoEmit (ec, false))
5701                                 ec.ig.Emit (OpCodes.Pop);
5702                 }
5703
5704                 public void AddressOf (EmitContext ec, AddressOp Mode)
5705                 {
5706                         if (!type.IsValueType){
5707                                 //
5708                                 // We throw an exception.  So far, I believe we only need to support
5709                                 // value types:
5710                                 // foreach (int j in new StructType ())
5711                                 // see bug 42390
5712                                 //
5713                                 throw new Exception ("AddressOf should not be used for classes");
5714                         }
5715
5716                         if (!value_target_set)
5717                                 value_target = new LocalTemporary (ec, type);
5718
5719                         IMemoryLocation ml = (IMemoryLocation) value_target;
5720                         ml.AddressOf (ec, AddressOp.Store);
5721                         if (method != null)
5722                                 Invocation.EmitArguments (ec, method, Arguments, false, null);
5723
5724                         if (method == null)
5725                                 ec.ig.Emit (OpCodes.Initobj, type);
5726                         else
5727                                 ec.ig.Emit (OpCodes.Call, (ConstructorInfo) method);
5728
5729                         ((IMemoryLocation) value_target).AddressOf (ec, Mode);
5730                 }
5731         }
5732
5733         /// <summary>
5734         ///   14.5.10.2: Represents an array creation expression.
5735         /// </summary>
5736         ///
5737         /// <remarks>
5738         ///   There are two possible scenarios here: one is an array creation
5739         ///   expression that specifies the dimensions and optionally the
5740         ///   initialization data and the other which does not need dimensions
5741         ///   specified but where initialization data is mandatory.
5742         /// </remarks>
5743         public class ArrayCreation : Expression {
5744                 Expression requested_base_type;
5745                 ArrayList initializers;
5746
5747                 //
5748                 // The list of Argument types.
5749                 // This is used to construct the `newarray' or constructor signature
5750                 //
5751                 ArrayList arguments;
5752
5753                 //
5754                 // Method used to create the array object.
5755                 //
5756                 MethodBase new_method = null;
5757
5758                 Type array_element_type;
5759                 Type underlying_type;
5760                 bool is_one_dimensional = false;
5761                 bool is_builtin_type = false;
5762                 bool expect_initializers = false;
5763                 int num_arguments = 0;
5764                 int dimensions = 0;
5765                 string rank;
5766
5767                 ArrayList array_data;
5768
5769                 Hashtable bounds;
5770
5771                 //
5772                 // The number of array initializers that we can handle
5773                 // via the InitializeArray method - through EmitStaticInitializers
5774                 //
5775                 int num_automatic_initializers;
5776
5777                 const int max_automatic_initializers = 6;
5778
5779                 public ArrayCreation (Expression requested_base_type, ArrayList exprs, string rank, ArrayList initializers, Location l)
5780                 {
5781                         this.requested_base_type = requested_base_type;
5782                         this.initializers = initializers;
5783                         this.rank = rank;
5784                         loc = l;
5785
5786                         arguments = new ArrayList ();
5787
5788                         foreach (Expression e in exprs) {
5789                                 arguments.Add (new Argument (e, Argument.AType.Expression));
5790                                 num_arguments++;
5791                         }
5792                 }
5793
5794                 public ArrayCreation (Expression requested_base_type, string rank, ArrayList initializers, Location l)
5795                 {
5796                         this.requested_base_type = requested_base_type;
5797                         this.initializers = initializers;
5798                         this.rank = rank;
5799                         loc = l;
5800
5801                         //this.rank = rank.Substring (0, rank.LastIndexOf ('['));
5802                         //
5803                         //string tmp = rank.Substring (rank.LastIndexOf ('['));
5804                         //
5805                         //dimensions = tmp.Length - 1;
5806                         expect_initializers = true;
5807                 }
5808
5809                 public Expression FormArrayType (Expression base_type, int idx_count, string rank)
5810                 {
5811                         StringBuilder sb = new StringBuilder (rank);
5812
5813                         sb.Append ("[");
5814                         for (int i = 1; i < idx_count; i++)
5815                                 sb.Append (",");
5816
5817                         sb.Append ("]");
5818
5819                         return new ComposedCast (base_type, sb.ToString (), loc);
5820                 }
5821
5822                 void Error_IncorrectArrayInitializer ()
5823                 {
5824                         Error (178, "Incorrectly structured array initializer");
5825                 }
5826
5827                 public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
5828                 {
5829                         if (specified_dims) {
5830                                 Argument a = (Argument) arguments [idx];
5831
5832                                 if (!a.Resolve (ec, loc))
5833                                         return false;
5834
5835                                 if (!(a.Expr is Constant)) {
5836                                         Error (150, "A constant value is expected");
5837                                         return false;
5838                                 }
5839
5840                                 int value = (int) ((Constant) a.Expr).GetValue ();
5841
5842                                 if (value != probe.Count) {
5843                                         Error_IncorrectArrayInitializer ();
5844                                         return false;
5845                                 }
5846
5847                                 bounds [idx] = value;
5848                         }
5849
5850                         int child_bounds = -1;
5851                         foreach (object o in probe) {
5852                                 if (o is ArrayList) {
5853                                         int current_bounds = ((ArrayList) o).Count;
5854
5855                                         if (child_bounds == -1)
5856                                                 child_bounds = current_bounds;
5857
5858                                         else if (child_bounds != current_bounds){
5859                                                 Error_IncorrectArrayInitializer ();
5860                                                 return false;
5861                                         }
5862                                         if (specified_dims && (idx + 1 >= arguments.Count)){
5863                                                 Error (623, "Array initializers can only be used in a variable or field initializer, try using the new expression");
5864                                                 return false;
5865                                         }
5866
5867                                         bool ret = CheckIndices (ec, (ArrayList) o, idx + 1, specified_dims);
5868                                         if (!ret)
5869                                                 return false;
5870                                 } else {
5871                                         if (child_bounds != -1){
5872                                                 Error_IncorrectArrayInitializer ();
5873                                                 return false;
5874                                         }
5875
5876                                         Expression tmp = (Expression) o;
5877                                         tmp = tmp.Resolve (ec);
5878                                         if (tmp == null)
5879                                                 return false;
5880
5881                                         // Console.WriteLine ("I got: " + tmp);
5882                                         // Handle initialization from vars, fields etc.
5883
5884                                         Expression conv = Convert.ImplicitConversionRequired (
5885                                                 ec, tmp, underlying_type, loc);
5886
5887                                         if (conv == null)
5888                                                 return false;
5889
5890                                         if (conv is StringConstant || conv is DecimalConstant || conv is NullCast) {
5891                                                 // These are subclasses of Constant that can appear as elements of an
5892                                                 // array that cannot be statically initialized (with num_automatic_initializers
5893                                                 // > max_automatic_initializers), so num_automatic_initializers should be left as zero.
5894                                                 array_data.Add (conv);
5895                                         } else if (conv is Constant) {
5896                                                 // These are the types of Constant that can appear in arrays that can be
5897                                                 // statically allocated.
5898                                                 array_data.Add (conv);
5899                                                 num_automatic_initializers++;
5900                                         } else
5901                                                 array_data.Add (conv);
5902                                 }
5903                         }
5904
5905                         return true;
5906                 }
5907
5908                 public void UpdateIndices (EmitContext ec)
5909                 {
5910                         int i = 0;
5911                         for (ArrayList probe = initializers; probe != null;) {
5912                                 if (probe.Count > 0 && probe [0] is ArrayList) {
5913                                         Expression e = new IntConstant (probe.Count);
5914                                         arguments.Add (new Argument (e, Argument.AType.Expression));
5915
5916                                         bounds [i++] =  probe.Count;
5917
5918                                         probe = (ArrayList) probe [0];
5919
5920                                 } else {
5921                                         Expression e = new IntConstant (probe.Count);
5922                                         arguments.Add (new Argument (e, Argument.AType.Expression));
5923
5924                                         bounds [i++] = probe.Count;
5925                                         probe = null;
5926                                 }
5927                         }
5928
5929                 }
5930
5931                 public bool ValidateInitializers (EmitContext ec, Type array_type)
5932                 {
5933                         if (initializers == null) {
5934                                 if (expect_initializers)
5935                                         return false;
5936                                 else
5937                                         return true;
5938                         }
5939
5940                         if (underlying_type == null)
5941                                 return false;
5942
5943                         //
5944                         // We use this to store all the date values in the order in which we
5945                         // will need to store them in the byte blob later
5946                         //
5947                         array_data = new ArrayList ();
5948                         bounds = new Hashtable ();
5949
5950                         bool ret;
5951
5952                         if (arguments != null) {
5953                                 ret = CheckIndices (ec, initializers, 0, true);
5954                                 return ret;
5955                         } else {
5956                                 arguments = new ArrayList ();
5957
5958                                 ret = CheckIndices (ec, initializers, 0, false);
5959
5960                                 if (!ret)
5961                                         return false;
5962
5963                                 UpdateIndices (ec);
5964
5965                                 if (arguments.Count != dimensions) {
5966                                         Error_IncorrectArrayInitializer ();
5967                                         return false;
5968                                 }
5969
5970                                 return ret;
5971                         }
5972                 }
5973
5974                 //
5975                 // Converts `source' to an int, uint, long or ulong.
5976                 //
5977                 Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
5978                 {
5979                         Expression target;
5980
5981                         bool old_checked = ec.CheckState;
5982                         ec.CheckState = true;
5983
5984                         target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
5985                         if (target == null){
5986                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
5987                                 if (target == null){
5988                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
5989                                         if (target == null){
5990                                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
5991                                                 if (target == null)
5992                                                         Convert.Error_CannotImplicitConversion (loc, source.Type, TypeManager.int32_type);
5993                                         }
5994                                 }
5995                         }
5996                         ec.CheckState = old_checked;
5997
5998                         //
5999                         // Only positive constants are allowed at compile time
6000                         //
6001                         if (target is Constant){
6002                                 if (target is IntConstant){
6003                                         if (((IntConstant) target).Value < 0){
6004                                                 Expression.Error_NegativeArrayIndex (loc);
6005                                                 return null;
6006                                         }
6007                                 }
6008
6009                                 if (target is LongConstant){
6010                                         if (((LongConstant) target).Value < 0){
6011                                                 Expression.Error_NegativeArrayIndex (loc);
6012                                                 return null;
6013                                         }
6014                                 }
6015
6016                         }
6017
6018                         return target;
6019                 }
6020
6021                 //
6022                 // Creates the type of the array
6023                 //
6024                 bool LookupType (EmitContext ec)
6025                 {
6026                         StringBuilder array_qualifier = new StringBuilder (rank);
6027
6028                         //
6029                         // `In the first form allocates an array instace of the type that results
6030                         // from deleting each of the individual expression from the expression list'
6031                         //
6032                         if (num_arguments > 0) {
6033                                 array_qualifier.Append ("[");
6034                                 for (int i = num_arguments-1; i > 0; i--)
6035                                         array_qualifier.Append (",");
6036                                 array_qualifier.Append ("]");
6037                         }
6038
6039                         //
6040                         // Lookup the type
6041                         //
6042                         Expression array_type_expr;
6043                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
6044                         type = ec.DeclSpace.ResolveType (array_type_expr, false, loc);
6045
6046                         if (type == null)
6047                                 return false;
6048
6049                         if (!type.IsArray) {
6050                                 Error (622, "Can only use array initializer expressions to assign to array types. Try using a new expression instead.");
6051                                 return false;
6052                         }
6053                         underlying_type = TypeManager.GetElementType (type);
6054                         dimensions = type.GetArrayRank ();
6055
6056                         return true;
6057                 }
6058
6059                 public override Expression DoResolve (EmitContext ec)
6060                 {
6061                         int arg_count;
6062
6063                         if (!LookupType (ec))
6064                                 return null;
6065
6066                         //
6067                         // First step is to validate the initializers and fill
6068                         // in any missing bits
6069                         //
6070                         if (!ValidateInitializers (ec, type))
6071                                 return null;
6072
6073                         if (arguments == null)
6074                                 arg_count = 0;
6075                         else {
6076                                 arg_count = arguments.Count;
6077                                 foreach (Argument a in arguments){
6078                                         if (!a.Resolve (ec, loc))
6079                                                 return null;
6080
6081                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
6082                                         if (real_arg == null)
6083                                                 return null;
6084
6085                                         a.Expr = real_arg;
6086                                 }
6087                         }
6088
6089                         array_element_type = TypeManager.GetElementType (type);
6090
6091                         if (array_element_type.IsAbstract && array_element_type.IsSealed) {
6092                                 Report.Error (719, loc, "'{0}': array elements cannot be of static type", TypeManager.CSharpName (array_element_type));
6093                                 return null;
6094                         }
6095
6096                         if (arg_count == 1) {
6097                                 is_one_dimensional = true;
6098                                 eclass = ExprClass.Value;
6099                                 return this;
6100                         }
6101
6102                         is_builtin_type = TypeManager.IsBuiltinType (type);
6103
6104                         if (is_builtin_type) {
6105                                 Expression ml;
6106
6107                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
6108                                                    AllBindingFlags, loc);
6109
6110                                 if (!(ml is MethodGroupExpr)) {
6111                                         ml.Error_UnexpectedKind ("method group");
6112                                         return null;
6113                                 }
6114
6115                                 if (ml == null) {
6116                                         Error (-6, "New invocation: Can not find a constructor for " +
6117                                                       "this argument list");
6118                                         return null;
6119                                 }
6120
6121                                 new_method = Invocation.OverloadResolve (
6122                                         ec, (MethodGroupExpr) ml, arguments, false, loc);
6123
6124                                 if (new_method == null) {
6125                                         Error (-6, "New invocation: Can not find a constructor for " +
6126                                                       "this argument list");
6127                                         return null;
6128                                 }
6129
6130                                 eclass = ExprClass.Value;
6131                                 return this;
6132                         } else {
6133                                 ModuleBuilder mb = CodeGen.Module.Builder;
6134                                 ArrayList args = new ArrayList ();
6135
6136                                 if (arguments != null) {
6137                                         for (int i = 0; i < arg_count; i++)
6138                                                 args.Add (TypeManager.int32_type);
6139                                 }
6140
6141                                 Type [] arg_types = null;
6142
6143                                 if (args.Count > 0)
6144                                         arg_types = new Type [args.Count];
6145
6146                                 args.CopyTo (arg_types, 0);
6147
6148                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
6149                                                             arg_types);
6150
6151                                 if (new_method == null) {
6152                                         Error (-6, "New invocation: Can not find a constructor for " +
6153                                                       "this argument list");
6154                                         return null;
6155                                 }
6156
6157                                 eclass = ExprClass.Value;
6158                                 return this;
6159                         }
6160                 }
6161
6162                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
6163                 {
6164                         int factor;
6165                         byte [] data;
6166                         byte [] element;
6167                         int count = array_data.Count;
6168
6169                         if (underlying_type.IsEnum)
6170                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
6171
6172                         factor = GetTypeSize (underlying_type);
6173                         if (factor == 0)
6174                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
6175
6176                         data = new byte [(count * factor + 4) & ~3];
6177                         int idx = 0;
6178
6179                         for (int i = 0; i < count; ++i) {
6180                                 object v = array_data [i];
6181
6182                                 if (v is EnumConstant)
6183                                         v = ((EnumConstant) v).Child;
6184
6185                                 if (v is Constant && !(v is StringConstant))
6186                                         v = ((Constant) v).GetValue ();
6187                                 else {
6188                                         idx += factor;
6189                                         continue;
6190                                 }
6191
6192                                 if (underlying_type == TypeManager.int64_type){
6193                                         if (!(v is Expression)){
6194                                                 long val = (long) v;
6195
6196                                                 for (int j = 0; j < factor; ++j) {
6197                                                         data [idx + j] = (byte) (val & 0xFF);
6198                                                         val = (val >> 8);
6199                                                 }
6200                                         }
6201                                 } else if (underlying_type == TypeManager.uint64_type){
6202                                         if (!(v is Expression)){
6203                                                 ulong val = (ulong) v;
6204
6205                                                 for (int j = 0; j < factor; ++j) {
6206                                                         data [idx + j] = (byte) (val & 0xFF);
6207                                                         val = (val >> 8);
6208                                                 }
6209                                         }
6210                                 } else if (underlying_type == TypeManager.float_type) {
6211                                         if (!(v is Expression)){
6212                                                 element = BitConverter.GetBytes ((float) v);
6213
6214                                                 for (int j = 0; j < factor; ++j)
6215                                                         data [idx + j] = element [j];
6216                                         }
6217                                 } else if (underlying_type == TypeManager.double_type) {
6218                                         if (!(v is Expression)){
6219                                                 element = BitConverter.GetBytes ((double) v);
6220
6221                                                 for (int j = 0; j < factor; ++j)
6222                                                         data [idx + j] = element [j];
6223                                         }
6224                                 } else if (underlying_type == TypeManager.char_type){
6225                                         if (!(v is Expression)){
6226                                                 int val = (int) ((char) v);
6227
6228                                                 data [idx] = (byte) (val & 0xff);
6229                                                 data [idx+1] = (byte) (val >> 8);
6230                                         }
6231                                 } else if (underlying_type == TypeManager.short_type){
6232                                         if (!(v is Expression)){
6233                                                 int val = (int) ((short) v);
6234
6235                                                 data [idx] = (byte) (val & 0xff);
6236                                                 data [idx+1] = (byte) (val >> 8);
6237                                         }
6238                                 } else if (underlying_type == TypeManager.ushort_type){
6239                                         if (!(v is Expression)){
6240                                                 int val = (int) ((ushort) v);
6241
6242                                                 data [idx] = (byte) (val & 0xff);
6243                                                 data [idx+1] = (byte) (val >> 8);
6244                                         }
6245                                 } else if (underlying_type == TypeManager.int32_type) {
6246                                         if (!(v is Expression)){
6247                                                 int val = (int) v;
6248
6249                                                 data [idx]   = (byte) (val & 0xff);
6250                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6251                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6252                                                 data [idx+3] = (byte) (val >> 24);
6253                                         }
6254                                 } else if (underlying_type == TypeManager.uint32_type) {
6255                                         if (!(v is Expression)){
6256                                                 uint val = (uint) v;
6257
6258                                                 data [idx]   = (byte) (val & 0xff);
6259                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6260                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6261                                                 data [idx+3] = (byte) (val >> 24);
6262                                         }
6263                                 } else if (underlying_type == TypeManager.sbyte_type) {
6264                                         if (!(v is Expression)){
6265                                                 sbyte val = (sbyte) v;
6266                                                 data [idx] = (byte) val;
6267                                         }
6268                                 } else if (underlying_type == TypeManager.byte_type) {
6269                                         if (!(v is Expression)){
6270                                                 byte val = (byte) v;
6271                                                 data [idx] = (byte) val;
6272                                         }
6273                                 } else if (underlying_type == TypeManager.bool_type) {
6274                                         if (!(v is Expression)){
6275                                                 bool val = (bool) v;
6276                                                 data [idx] = (byte) (val ? 1 : 0);
6277                                         }
6278                                 } else if (underlying_type == TypeManager.decimal_type){
6279                                         if (!(v is Expression)){
6280                                                 int [] bits = Decimal.GetBits ((decimal) v);
6281                                                 int p = idx;
6282
6283                                                 // FIXME: For some reason, this doesn't work on the MS runtime.
6284                                                 int [] nbits = new int [4];
6285                                                 nbits [0] = bits [3];
6286                                                 nbits [1] = bits [2];
6287                                                 nbits [2] = bits [0];
6288                                                 nbits [3] = bits [1];
6289
6290                                                 for (int j = 0; j < 4; j++){
6291                                                         data [p++] = (byte) (nbits [j] & 0xff);
6292                                                         data [p++] = (byte) ((nbits [j] >> 8) & 0xff);
6293                                                         data [p++] = (byte) ((nbits [j] >> 16) & 0xff);
6294                                                         data [p++] = (byte) (nbits [j] >> 24);
6295                                                 }
6296                                         }
6297                                 } else
6298                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
6299
6300                                 idx += factor;
6301                         }
6302
6303                         return data;
6304                 }
6305
6306                 //
6307                 // Emits the initializers for the array
6308                 //
6309                 void EmitStaticInitializers (EmitContext ec)
6310                 {
6311                         //
6312                         // First, the static data
6313                         //
6314                         FieldBuilder fb;
6315                         ILGenerator ig = ec.ig;
6316
6317                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
6318
6319                         fb = RootContext.MakeStaticData (data);
6320
6321                         ig.Emit (OpCodes.Dup);
6322                         ig.Emit (OpCodes.Ldtoken, fb);
6323                         ig.Emit (OpCodes.Call,
6324                                  TypeManager.void_initializearray_array_fieldhandle);
6325                 }
6326
6327                 //
6328                 // Emits pieces of the array that can not be computed at compile
6329                 // time (variables and string locations).
6330                 //
6331                 // This always expect the top value on the stack to be the array
6332                 //
6333                 void EmitDynamicInitializers (EmitContext ec)
6334                 {
6335                         ILGenerator ig = ec.ig;
6336                         int dims = bounds.Count;
6337                         int [] current_pos = new int [dims];
6338                         int top = array_data.Count;
6339
6340                         MethodInfo set = null;
6341
6342                         if (dims != 1){
6343                                 Type [] args;
6344                                 ModuleBuilder mb = null;
6345                                 mb = CodeGen.Module.Builder;
6346                                 args = new Type [dims + 1];
6347
6348                                 int j;
6349                                 for (j = 0; j < dims; j++)
6350                                         args [j] = TypeManager.int32_type;
6351
6352                                 args [j] = array_element_type;
6353
6354                                 set = mb.GetArrayMethod (
6355                                         type, "Set",
6356                                         CallingConventions.HasThis | CallingConventions.Standard,
6357                                         TypeManager.void_type, args);
6358                         }
6359
6360                         for (int i = 0; i < top; i++){
6361
6362                                 Expression e = null;
6363
6364                                 if (array_data [i] is Expression)
6365                                         e = (Expression) array_data [i];
6366
6367                                 if (e != null) {
6368                                         //
6369                                         // Basically we do this for string literals and
6370                                         // other non-literal expressions
6371                                         //
6372                                         if (e is EnumConstant){
6373                                                 e = ((EnumConstant) e).Child;
6374                                         }
6375
6376                                         if (e is StringConstant || e is DecimalConstant || !(e is Constant) ||
6377                                             num_automatic_initializers <= max_automatic_initializers) {
6378                                                 Type etype = e.Type;
6379
6380                                                 ig.Emit (OpCodes.Dup);
6381
6382                                                 for (int idx = 0; idx < dims; idx++)
6383                                                         IntConstant.EmitInt (ig, current_pos [idx]);
6384
6385                                                 //
6386                                                 // If we are dealing with a struct, get the
6387                                                 // address of it, so we can store it.
6388                                                 //
6389                                                 if ((dims == 1) &&
6390                                                     etype.IsSubclassOf (TypeManager.value_type) &&
6391                                                     (!TypeManager.IsBuiltinOrEnum (etype) ||
6392                                                      etype == TypeManager.decimal_type)) {
6393                                                         if (e is New){
6394                                                                 New n = (New) e;
6395
6396                                                                 //
6397                                                                 // Let new know that we are providing
6398                                                                 // the address where to store the results
6399                                                                 //
6400                                                                 n.DisableTemporaryValueType ();
6401                                                         }
6402
6403                                                         ig.Emit (OpCodes.Ldelema, etype);
6404                                                 }
6405
6406                                                 e.Emit (ec);
6407
6408                                                 if (dims == 1) {
6409                                                         bool is_stobj;
6410                                                         OpCode op = ArrayAccess.GetStoreOpcode (etype, out is_stobj);
6411                                                         if (is_stobj)
6412                                                                 ig.Emit (OpCodes.Stobj, etype);
6413                                                         else
6414                                                                 ig.Emit (op);
6415                                                 } else
6416                                                         ig.Emit (OpCodes.Call, set);
6417
6418                                         }
6419                                 }
6420
6421                                 //
6422                                 // Advance counter
6423                                 //
6424                                 for (int j = dims - 1; j >= 0; j--){
6425                                         current_pos [j]++;
6426                                         if (current_pos [j] < (int) bounds [j])
6427                                                 break;
6428                                         current_pos [j] = 0;
6429                                 }
6430                         }
6431                 }
6432
6433                 void EmitArrayArguments (EmitContext ec)
6434                 {
6435                         ILGenerator ig = ec.ig;
6436
6437                         foreach (Argument a in arguments) {
6438                                 Type atype = a.Type;
6439                                 a.Emit (ec);
6440
6441                                 if (atype == TypeManager.uint64_type)
6442                                         ig.Emit (OpCodes.Conv_Ovf_U4);
6443                                 else if (atype == TypeManager.int64_type)
6444                                         ig.Emit (OpCodes.Conv_Ovf_I4);
6445                         }
6446                 }
6447
6448                 public override void Emit (EmitContext ec)
6449                 {
6450                         ILGenerator ig = ec.ig;
6451
6452                         EmitArrayArguments (ec);
6453                         if (is_one_dimensional)
6454                                 ig.Emit (OpCodes.Newarr, array_element_type);
6455                         else {
6456                                 if (is_builtin_type)
6457                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
6458                                 else
6459                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
6460                         }
6461
6462                         if (initializers != null){
6463                                 //
6464                                 // FIXME: Set this variable correctly.
6465                                 //
6466                                 bool dynamic_initializers = true;
6467
6468                                 // This will never be true for array types that cannot be statically
6469                                 // initialized. num_automatic_initializers will always be zero.  See
6470                                 // CheckIndices.
6471                                 if (num_automatic_initializers > max_automatic_initializers)
6472                                         EmitStaticInitializers (ec);
6473
6474                                 if (dynamic_initializers)
6475                                         EmitDynamicInitializers (ec);
6476                         }
6477                 }
6478
6479                 public object EncodeAsAttribute ()
6480                 {
6481                         if (!is_one_dimensional){
6482                                 Report.Error (-211, Location, "attribute can not encode multi-dimensional arrays");
6483                                 return null;
6484                         }
6485
6486                         if (array_data == null){
6487                                 Report.Error (-212, Location, "array should be initialized when passing it to an attribute");
6488                                 return null;
6489                         }
6490
6491                         object [] ret = new object [array_data.Count];
6492                         int i = 0;
6493                         foreach (Expression e in array_data){
6494                                 object v;
6495
6496                                 if (e is NullLiteral)
6497                                         v = null;
6498                                 else {
6499                                         if (!Attribute.GetAttributeArgumentExpression (e, Location, array_element_type, out v))
6500                                                 return null;
6501                                 }
6502                                 ret [i++] = v;
6503                         }
6504                         return ret;
6505                 }
6506         }
6507
6508         /// <summary>
6509         ///   Represents the `this' construct
6510         /// </summary>
6511         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
6512
6513                 Block block;
6514                 VariableInfo variable_info;
6515
6516                 public This (Block block, Location loc)
6517                 {
6518                         this.loc = loc;
6519                         this.block = block;
6520                 }
6521
6522                 public This (Location loc)
6523                 {
6524                         this.loc = loc;
6525                 }
6526
6527                 public VariableInfo VariableInfo {
6528                         get { return variable_info; }
6529                 }
6530
6531                 public bool VerifyFixed (bool is_expression)
6532                 {
6533                         if ((variable_info == null) || (variable_info.LocalInfo == null))
6534                                 return false;
6535                         else
6536                                 return variable_info.LocalInfo.IsFixed;
6537                 }
6538
6539                 public bool ResolveBase (EmitContext ec)
6540                 {
6541                         eclass = ExprClass.Variable;
6542                         type = ec.ContainerType;
6543
6544                         if (ec.IsStatic) {
6545                                 Error (26, "Keyword this not valid in static code");
6546                                 return false;
6547                         }
6548
6549                         if ((block != null) && (block.ThisVariable != null))
6550                                 variable_info = block.ThisVariable.VariableInfo;
6551
6552                         return true;
6553                 }
6554
6555                 public override Expression DoResolve (EmitContext ec)
6556                 {
6557                         if (!ResolveBase (ec))
6558                                 return null;
6559
6560                         if ((variable_info != null) && !variable_info.IsAssigned (ec)) {
6561                                 Error (188, "The this object cannot be used before all " +
6562                                        "of its fields are assigned to");
6563                                 variable_info.SetAssigned (ec);
6564                                 return this;
6565                         }
6566
6567                         if (ec.IsFieldInitializer) {
6568                                 Error (27, "Keyword `this' can't be used outside a constructor, " +
6569                                        "a method or a property.");
6570                                 return null;
6571                         }
6572
6573                         return this;
6574                 }
6575
6576                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
6577                 {
6578                         if (!ResolveBase (ec))
6579                                 return null;
6580
6581                         if (variable_info != null)
6582                                 variable_info.SetAssigned (ec);
6583
6584                         if (ec.TypeContainer is Class){
6585                                 Error (1604, "Cannot assign to `this'");
6586                                 return null;
6587                         }
6588
6589                         return this;
6590                 }
6591
6592                 public void Emit (EmitContext ec, bool leave_copy)
6593                 {
6594                         Emit (ec);
6595                         if (leave_copy)
6596                                 ec.ig.Emit (OpCodes.Dup);
6597                 }
6598
6599                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
6600                 {
6601                         ILGenerator ig = ec.ig;
6602
6603                         if (ec.TypeContainer is Struct){
6604                                 ec.EmitThis ();
6605                                 source.Emit (ec);
6606                                 if (leave_copy)
6607                                         ec.ig.Emit (OpCodes.Dup);
6608                                 ig.Emit (OpCodes.Stobj, type);
6609                         } else {
6610                                 throw new Exception ("how did you get here");
6611                         }
6612                 }
6613
6614                 public override void Emit (EmitContext ec)
6615                 {
6616                         ILGenerator ig = ec.ig;
6617
6618                         ec.EmitThis ();
6619                         if (ec.TypeContainer is Struct)
6620                                 ig.Emit (OpCodes.Ldobj, type);
6621                 }
6622
6623                 public void AddressOf (EmitContext ec, AddressOp mode)
6624                 {
6625                         ec.EmitThis ();
6626
6627                         // FIMXE
6628                         // FIGURE OUT WHY LDARG_S does not work
6629                         //
6630                         // consider: struct X { int val; int P { set { val = value; }}}
6631                         //
6632                         // Yes, this looks very bad. Look at `NOTAS' for
6633                         // an explanation.
6634                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
6635                 }
6636         }
6637
6638         /// <summary>
6639         ///   Represents the `__arglist' construct
6640         /// </summary>
6641         public class ArglistAccess : Expression
6642         {
6643                 public ArglistAccess (Location loc)
6644                 {
6645                         this.loc = loc;
6646                 }
6647
6648                 public bool ResolveBase (EmitContext ec)
6649                 {
6650                         eclass = ExprClass.Variable;
6651                         type = TypeManager.runtime_argument_handle_type;
6652                         return true;
6653                 }
6654
6655                 public override Expression DoResolve (EmitContext ec)
6656                 {
6657                         if (!ResolveBase (ec))
6658                                 return null;
6659
6660                         if (ec.IsFieldInitializer || !ec.CurrentBlock.HasVarargs) {
6661                                 Error (190, "The __arglist construct is valid only within " +
6662                                        "a variable argument method.");
6663                                 return null;
6664                         }
6665
6666                         return this;
6667                 }
6668
6669                 public override void Emit (EmitContext ec)
6670                 {
6671                         ec.ig.Emit (OpCodes.Arglist);
6672                 }
6673         }
6674
6675         /// <summary>
6676         ///   Represents the `__arglist (....)' construct
6677         /// </summary>
6678         public class Arglist : Expression
6679         {
6680                 public readonly Argument[] Arguments;
6681
6682                 public Arglist (Argument[] args, Location l)
6683                 {
6684                         Arguments = args;
6685                         loc = l;
6686                 }
6687
6688                 public Type[] ArgumentTypes {
6689                         get {
6690                                 Type[] retval = new Type [Arguments.Length];
6691                                 for (int i = 0; i < Arguments.Length; i++)
6692                                         retval [i] = Arguments [i].Type;
6693                                 return retval;
6694                         }
6695                 }
6696
6697                 public override Expression DoResolve (EmitContext ec)
6698                 {
6699                         eclass = ExprClass.Variable;
6700                         type = TypeManager.runtime_argument_handle_type;
6701
6702                         foreach (Argument arg in Arguments) {
6703                                 if (!arg.Resolve (ec, loc))
6704                                         return null;
6705                         }
6706
6707                         return this;
6708                 }
6709
6710                 public override void Emit (EmitContext ec)
6711                 {
6712                         foreach (Argument arg in Arguments)
6713                                 arg.Emit (ec);
6714                 }
6715         }
6716
6717         //
6718         // This produces the value that renders an instance, used by the iterators code
6719         //
6720         public class ProxyInstance : Expression, IMemoryLocation  {
6721                 public override Expression DoResolve (EmitContext ec)
6722                 {
6723                         eclass = ExprClass.Variable;
6724                         type = ec.ContainerType;
6725                         return this;
6726                 }
6727
6728                 public override void Emit (EmitContext ec)
6729                 {
6730                         ec.ig.Emit (OpCodes.Ldarg_0);
6731
6732                 }
6733
6734                 public void AddressOf (EmitContext ec, AddressOp mode)
6735                 {
6736                         ec.ig.Emit (OpCodes.Ldarg_0);
6737                 }
6738         }
6739
6740         /// <summary>
6741         ///   Implements the typeof operator
6742         /// </summary>
6743         public class TypeOf : Expression {
6744                 public readonly Expression QueriedType;
6745                 protected Type typearg;
6746
6747                 public TypeOf (Expression queried_type, Location l)
6748                 {
6749                         QueriedType = queried_type;
6750                         loc = l;
6751                 }
6752
6753                 public override Expression DoResolve (EmitContext ec)
6754                 {
6755                         typearg = ec.DeclSpace.ResolveType (QueriedType, false, loc);
6756
6757                         if (typearg == null)
6758                                 return null;
6759
6760                         if (typearg == TypeManager.void_type) {
6761                                 Error (673, "System.Void cannot be used from C# - " +
6762                                        "use typeof (void) to get the void type object");
6763                                 return null;
6764                         }
6765
6766                         if (typearg.IsPointer && !ec.InUnsafe){
6767                                 UnsafeError (loc);
6768                                 return null;
6769                         }
6770                         CheckObsoleteAttribute (typearg);
6771
6772                         type = TypeManager.type_type;
6773                         eclass = ExprClass.Type;
6774                         return this;
6775                 }
6776
6777                 public override void Emit (EmitContext ec)
6778                 {
6779                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
6780                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
6781                 }
6782
6783                 public Type TypeArg {
6784                         get { return typearg; }
6785                 }
6786         }
6787
6788         /// <summary>
6789         ///   Implements the `typeof (void)' operator
6790         /// </summary>
6791         public class TypeOfVoid : TypeOf {
6792                 public TypeOfVoid (Location l) : base (null, l)
6793                 {
6794                         loc = l;
6795                 }
6796
6797                 public override Expression DoResolve (EmitContext ec)
6798                 {
6799                         type = TypeManager.type_type;
6800                         typearg = TypeManager.void_type;
6801                         eclass = ExprClass.Type;
6802                         return this;
6803                 }
6804         }
6805
6806         /// <summary>
6807         ///   Implements the sizeof expression
6808         /// </summary>
6809         public class SizeOf : Expression {
6810                 public readonly Expression QueriedType;
6811                 Type type_queried;
6812
6813                 public SizeOf (Expression queried_type, Location l)
6814                 {
6815                         this.QueriedType = queried_type;
6816                         loc = l;
6817                 }
6818
6819                 public override Expression DoResolve (EmitContext ec)
6820                 {
6821                         if (!ec.InUnsafe) {
6822                                 Report.Error (
6823                                         233, loc, "Sizeof may only be used in an unsafe context " +
6824                                         "(consider using System.Runtime.InteropServices.Marshal.Sizeof");
6825                                 return null;
6826                         }
6827
6828                         type_queried = ec.DeclSpace.ResolveType (QueriedType, false, loc);
6829                         if (type_queried == null)
6830                                 return null;
6831
6832                         CheckObsoleteAttribute (type_queried);
6833
6834                         if (!TypeManager.IsUnmanagedType (type_queried)){
6835                                 Report.Error (208, loc, "Cannot take the size of an unmanaged type (" + TypeManager.CSharpName (type_queried) + ")");
6836                                 return null;
6837                         }
6838
6839                         type = TypeManager.int32_type;
6840                         eclass = ExprClass.Value;
6841                         return this;
6842                 }
6843
6844                 public override void Emit (EmitContext ec)
6845                 {
6846                         int size = GetTypeSize (type_queried);
6847
6848                         if (size == 0)
6849                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
6850                         else
6851                                 IntConstant.EmitInt (ec.ig, size);
6852                 }
6853         }
6854
6855         /// <summary>
6856         ///   Implements the member access expression
6857         /// </summary>
6858         public class MemberAccess : Expression {
6859                 public readonly string Identifier;
6860                 Expression expr;
6861
6862                 public MemberAccess (Expression expr, string id, Location l)
6863                 {
6864                         this.expr = expr;
6865                         Identifier = id;
6866                         loc = l;
6867                 }
6868
6869                 public Expression Expr {
6870                         get {
6871                                 return expr;
6872                         }
6873                 }
6874
6875                 public static void error176 (Location loc, string name)
6876                 {
6877                         Report.Error (176, loc, "Static member `" +
6878                                       name + "' cannot be accessed " +
6879                                       "with an instance reference, qualify with a " +
6880                                       "type name instead");
6881                 }
6882
6883                 public static bool IdenticalNameAndTypeName (EmitContext ec, Expression left_original, Expression left, Location loc)
6884                 {
6885                         SimpleName sn = left_original as SimpleName;
6886                         if (sn == null || left == null || left.Type.Name != sn.Name)
6887                                 return false;
6888
6889                         return RootContext.LookupType (ec.DeclSpace, sn.Name, true, loc) != null;
6890                 }
6891
6892                 public static Expression ResolveMemberAccess (EmitContext ec, Expression member_lookup,
6893                                                               Expression left, Location loc,
6894                                                               Expression left_original)
6895                 {
6896                         bool left_is_type, left_is_explicit;
6897
6898                         // If `left' is null, then we're called from SimpleNameResolve and this is
6899                         // a member in the currently defining class.
6900                         if (left == null) {
6901                                 left_is_type = ec.IsStatic || ec.IsFieldInitializer;
6902                                 left_is_explicit = false;
6903
6904                                 // Implicitly default to `this' unless we're static.
6905                                 if (!ec.IsStatic && !ec.IsFieldInitializer && !ec.InEnumContext)
6906                                         left = ec.GetThis (loc);
6907                         } else {
6908                                 left_is_type = left is TypeExpr;
6909                                 left_is_explicit = true;
6910                         }
6911
6912                         if (member_lookup is FieldExpr){
6913                                 FieldExpr fe = (FieldExpr) member_lookup;
6914                                 FieldInfo fi = fe.FieldInfo;
6915                                 Type decl_type = fi.DeclaringType;
6916
6917                                 if (fi is FieldBuilder) {
6918                                         Const c = TypeManager.LookupConstant ((FieldBuilder) fi);
6919
6920                                         if (c != null) {
6921                                                 object o;
6922                                                 if (!c.LookupConstantValue (out o))
6923                                                         return null;
6924
6925                                                 object real_value = ((Constant) c.Expr).GetValue ();
6926
6927                                                 return Constantify (real_value, fi.FieldType);
6928                                         }
6929                                 }
6930
6931                                 if (fi.IsLiteral) {
6932                                         Type t = fi.FieldType;
6933
6934                                         object o;
6935
6936                                         if (fi is FieldBuilder)
6937                                                 o = TypeManager.GetValue ((FieldBuilder) fi);
6938                                         else
6939                                                 o = fi.GetValue (fi);
6940
6941                                         if (decl_type.IsSubclassOf (TypeManager.enum_type)) {
6942                                                 if (left_is_explicit && !left_is_type &&
6943                                                     !IdenticalNameAndTypeName (ec, left_original, member_lookup, loc)) {
6944                                                         error176 (loc, fe.FieldInfo.Name);
6945                                                         return null;
6946                                                 }
6947
6948                                                 Expression enum_member = MemberLookup (
6949                                                         ec, decl_type, "value__", MemberTypes.Field,
6950                                                         AllBindingFlags, loc);
6951
6952                                                 Enum en = TypeManager.LookupEnum (decl_type);
6953
6954                                                 Constant c;
6955                                                 if (en != null)
6956                                                         c = Constantify (o, en.UnderlyingType);
6957                                                 else
6958                                                         c = Constantify (o, enum_member.Type);
6959
6960                                                 return new EnumConstant (c, decl_type);
6961                                         }
6962
6963                                         Expression exp = Constantify (o, t);
6964
6965                                         if (left_is_explicit && !left_is_type) {
6966                                                 error176 (loc, fe.FieldInfo.Name);
6967                                                 return null;
6968                                         }
6969
6970                                         return exp;
6971                                 }
6972
6973                                 if (fi.FieldType.IsPointer && !ec.InUnsafe){
6974                                         UnsafeError (loc);
6975                                         return null;
6976                                 }
6977                         }
6978
6979                         if (member_lookup is EventExpr) {
6980                                 EventExpr ee = (EventExpr) member_lookup;
6981
6982                                 //
6983                                 // If the event is local to this class, we transform ourselves into
6984                                 // a FieldExpr
6985                                 //
6986
6987                                 if (ee.EventInfo.DeclaringType == ec.ContainerType ||
6988                                     TypeManager.IsNestedChildOf(ec.ContainerType, ee.EventInfo.DeclaringType)) {
6989                                         MemberInfo mi = GetFieldFromEvent (ee);
6990
6991                                         if (mi == null) {
6992                                                 //
6993                                                 // If this happens, then we have an event with its own
6994                                                 // accessors and private field etc so there's no need
6995                                                 // to transform ourselves.
6996                                                 //
6997                                                 ee.InstanceExpression = left;
6998                                                 return ee;
6999                                         }
7000
7001                                         Expression ml = ExprClassFromMemberInfo (ec, mi, loc);
7002
7003                                         if (ml == null) {
7004                                                 Report.Error (-200, loc, "Internal error!!");
7005                                                 return null;
7006                                         }
7007
7008                                         if (!left_is_explicit)
7009                                                 left = null;
7010
7011                                         ee.InstanceExpression = left;
7012
7013                                         return ResolveMemberAccess (ec, ml, left, loc, left_original);
7014                                 }
7015                         }
7016
7017                         if (member_lookup is IMemberExpr) {
7018                                 IMemberExpr me = (IMemberExpr) member_lookup;
7019                                 MethodGroupExpr mg = me as MethodGroupExpr;
7020
7021                                 if (left_is_type){
7022                                         if ((mg != null) && left_is_explicit && left.Type.IsInterface)
7023                                                 mg.IsExplicitImpl = left_is_explicit;
7024
7025                                         if (!me.IsStatic){
7026                                                 if ((ec.IsFieldInitializer || ec.IsStatic) &&
7027                                                     IdenticalNameAndTypeName (ec, left_original, member_lookup, loc))
7028                                                         return member_lookup;
7029
7030                                                 SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
7031                                                 return null;
7032                                         }
7033
7034                                 } else {
7035                                         if (!me.IsInstance) {
7036                                                 if (IdenticalNameAndTypeName (ec, left_original, left, loc))
7037                                                         return member_lookup;
7038
7039                                                 if (left_is_explicit) {
7040                                                         error176 (loc, me.Name);
7041                                                         return null;
7042                                                 }
7043                                         }
7044
7045                                         //
7046                                         // Since we can not check for instance objects in SimpleName,
7047                                         // becaue of the rule that allows types and variables to share
7048                                         // the name (as long as they can be de-ambiguated later, see
7049                                         // IdenticalNameAndTypeName), we have to check whether left
7050                                         // is an instance variable in a static context
7051                                         //
7052                                         // However, if the left-hand value is explicitly given, then
7053                                         // it is already our instance expression, so we aren't in
7054                                         // static context.
7055                                         //
7056
7057                                         if (ec.IsStatic && !left_is_explicit && left is IMemberExpr){
7058                                                 IMemberExpr mexp = (IMemberExpr) left;
7059
7060                                                 if (!mexp.IsStatic){
7061                                                         SimpleName.Error_ObjectRefRequired (ec, loc, mexp.Name);
7062                                                         return null;
7063                                                 }
7064                                         }
7065
7066                                         if ((mg != null) && IdenticalNameAndTypeName (ec, left_original, left, loc))
7067                                                 mg.IdenticalTypeName = true;
7068
7069                                         me.InstanceExpression = left;
7070                                 }
7071
7072                                 return member_lookup;
7073                         }
7074
7075                         Console.WriteLine ("Left is: " + left);
7076                         Report.Error (-100, loc, "Support for [" + member_lookup + "] is not present yet");
7077                         Environment.Exit (1);
7078                         return null;
7079                 }
7080
7081                 public Expression DoResolve (EmitContext ec, Expression right_side, ResolveFlags flags)
7082                 {
7083                         if (type != null)
7084                                 throw new Exception ();
7085
7086                         //
7087                         // Resolve the expression with flow analysis turned off, we'll do the definite
7088                         // assignment checks later.  This is because we don't know yet what the expression
7089                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
7090                         // definite assignment check on the actual field and not on the whole struct.
7091                         //
7092
7093                         Expression original = expr;
7094                         expr = expr.Resolve (ec, flags | ResolveFlags.Intermediate | ResolveFlags.DisableFlowAnalysis);
7095                         if (expr == null)
7096                                 return null;
7097
7098                         if (expr is SimpleName){
7099                                 SimpleName child_expr = (SimpleName) expr;
7100
7101                                 Expression new_expr = new SimpleName (child_expr.Name, Identifier, loc);
7102
7103                                 return new_expr.Resolve (ec, flags);
7104                         }
7105
7106                         //
7107                         // TODO: I mailed Ravi about this, and apparently we can get rid
7108                         // of this and put it in the right place.
7109                         //
7110                         // Handle enums here when they are in transit.
7111                         // Note that we cannot afford to hit MemberLookup in this case because
7112                         // it will fail to find any members at all
7113                         //
7114
7115                         Type expr_type = expr.Type;
7116                         if (expr is TypeExpr){
7117                                 if (!ec.DeclSpace.CheckAccessLevel (expr_type)){
7118                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", expr_type);
7119                                         return null;
7120                                 }
7121
7122                                 if (expr_type == TypeManager.enum_type || expr_type.IsSubclassOf (TypeManager.enum_type)){
7123                                         Enum en = TypeManager.LookupEnum (expr_type);
7124
7125                                         if (en != null) {
7126                                                 object value = en.LookupEnumValue (ec, Identifier, loc);
7127
7128                                                 if (value != null){
7129                                                         MemberCore mc = en.GetDefinition (Identifier);
7130                                                         ObsoleteAttribute oa = mc.GetObsoleteAttribute (en);
7131                                                         if (oa != null) {
7132                                                                 AttributeTester.Report_ObsoleteMessage (oa, mc.GetSignatureForError (), Location);
7133                                                         }
7134                                                         oa = en.GetObsoleteAttribute (en);
7135                                                         if (oa != null) {
7136                                                                 AttributeTester.Report_ObsoleteMessage (oa, en.GetSignatureForError (), Location);
7137                                                         }
7138
7139                                                         Constant c = Constantify (value, en.UnderlyingType);
7140                                                         return new EnumConstant (c, expr_type);
7141                                                 }
7142                                         } else {
7143                                                 CheckObsoleteAttribute (expr_type);
7144
7145                                                 FieldInfo fi = expr_type.GetField (Identifier);
7146                                                 if (fi != null) {
7147                                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (fi);
7148                                                         if (oa != null)
7149                                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (fi), Location);
7150                                                 }
7151                                         }
7152                                 }
7153                         }
7154
7155                         if (expr_type.IsPointer){
7156                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7157                                        TypeManager.CSharpName (expr_type) + ")");
7158                                 return null;
7159                         }
7160
7161                         Expression member_lookup;
7162                         member_lookup = MemberLookupFinal (ec, expr_type, expr_type, Identifier, loc);
7163                         if (member_lookup == null)
7164                                 return null;
7165
7166                         if (member_lookup is TypeExpr) {
7167                                 if (!(expr is TypeExpr) && !(expr is SimpleName)) {
7168                                         Error (572, "Can't reference type `" + Identifier + "' through an expression; try `" +
7169                                                member_lookup.Type + "' instead");
7170                                         return null;
7171                                 }
7172
7173                                 return member_lookup;
7174                         }
7175
7176                         member_lookup = ResolveMemberAccess (ec, member_lookup, expr, loc, original);
7177                         if (member_lookup == null)
7178                                 return null;
7179
7180                         // The following DoResolve/DoResolveLValue will do the definite assignment
7181                         // check.
7182
7183                         if (right_side != null)
7184                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
7185                         else
7186                                 member_lookup = member_lookup.DoResolve (ec);
7187
7188                         return member_lookup;
7189                 }
7190
7191                 public override Expression DoResolve (EmitContext ec)
7192                 {
7193                         return DoResolve (ec, null, ResolveFlags.VariableOrValue |
7194                                           ResolveFlags.SimpleName | ResolveFlags.Type);
7195                 }
7196
7197                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7198                 {
7199                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue |
7200                                           ResolveFlags.SimpleName | ResolveFlags.Type);
7201                 }
7202
7203                 public override Expression ResolveAsTypeStep (EmitContext ec)
7204                 {
7205                         string fname = null;
7206                         MemberAccess full_expr = this;
7207                         while (full_expr != null) {
7208                                 if (fname != null)
7209                                         fname = String.Concat (full_expr.Identifier, ".", fname);
7210                                 else
7211                                         fname = full_expr.Identifier;
7212
7213                                 if (full_expr.Expr is SimpleName) {
7214                                         string full_name = String.Concat (((SimpleName) full_expr.Expr).Name, ".", fname);
7215                                         Type fully_qualified = ec.DeclSpace.FindType (loc, full_name);
7216                                         if (fully_qualified != null)
7217                                                 return new TypeExpression (fully_qualified, loc);
7218                                 }
7219
7220                                 full_expr = full_expr.Expr as MemberAccess;
7221                         }
7222
7223                         Expression new_expr = expr.ResolveAsTypeStep (ec);
7224
7225                         if (new_expr == null)
7226                                 return null;
7227
7228                         if (new_expr is SimpleName){
7229                                 SimpleName child_expr = (SimpleName) new_expr;
7230
7231                                 new_expr = new SimpleName (child_expr.Name, Identifier, loc);
7232
7233                                 return new_expr.ResolveAsTypeStep (ec);
7234                         }
7235
7236                         Type expr_type = new_expr.Type;
7237
7238                         if (expr_type.IsPointer){
7239                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7240                                        TypeManager.CSharpName (expr_type) + ")");
7241                                 return null;
7242                         }
7243
7244                         Expression member_lookup;
7245                         member_lookup = MemberLookupFinal (ec, expr_type, expr_type, Identifier, loc);
7246                         if (member_lookup == null)
7247                                 return null;
7248
7249                         if (member_lookup is TypeExpr){
7250                                 member_lookup.Resolve (ec, ResolveFlags.Type);
7251                                 return member_lookup;
7252                         }
7253
7254                         return null;
7255                 }
7256
7257                 public override void Emit (EmitContext ec)
7258                 {
7259                         throw new Exception ("Should not happen");
7260                 }
7261
7262                 public override string ToString ()
7263                 {
7264                         return expr + "." + Identifier;
7265                 }
7266         }
7267
7268         /// <summary>
7269         ///   Implements checked expressions
7270         /// </summary>
7271         public class CheckedExpr : Expression {
7272
7273                 public Expression Expr;
7274
7275                 public CheckedExpr (Expression e, Location l)
7276                 {
7277                         Expr = e;
7278                         loc = l;
7279                 }
7280
7281                 public override Expression DoResolve (EmitContext ec)
7282                 {
7283                         bool last_check = ec.CheckState;
7284                         bool last_const_check = ec.ConstantCheckState;
7285
7286                         ec.CheckState = true;
7287                         ec.ConstantCheckState = true;
7288                         Expr = Expr.Resolve (ec);
7289                         ec.CheckState = last_check;
7290                         ec.ConstantCheckState = last_const_check;
7291
7292                         if (Expr == null)
7293                                 return null;
7294
7295                         if (Expr is Constant)
7296                                 return Expr;
7297
7298                         eclass = Expr.eclass;
7299                         type = Expr.Type;
7300                         return this;
7301                 }
7302
7303                 public override void Emit (EmitContext ec)
7304                 {
7305                         bool last_check = ec.CheckState;
7306                         bool last_const_check = ec.ConstantCheckState;
7307
7308                         ec.CheckState = true;
7309                         ec.ConstantCheckState = true;
7310                         Expr.Emit (ec);
7311                         ec.CheckState = last_check;
7312                         ec.ConstantCheckState = last_const_check;
7313                 }
7314
7315         }
7316
7317         /// <summary>
7318         ///   Implements the unchecked expression
7319         /// </summary>
7320         public class UnCheckedExpr : Expression {
7321
7322                 public Expression Expr;
7323
7324                 public UnCheckedExpr (Expression e, Location l)
7325                 {
7326                         Expr = e;
7327                         loc = l;
7328                 }
7329
7330                 public override Expression DoResolve (EmitContext ec)
7331                 {
7332                         bool last_check = ec.CheckState;
7333                         bool last_const_check = ec.ConstantCheckState;
7334
7335                         ec.CheckState = false;
7336                         ec.ConstantCheckState = false;
7337                         Expr = Expr.Resolve (ec);
7338                         ec.CheckState = last_check;
7339                         ec.ConstantCheckState = last_const_check;
7340
7341                         if (Expr == null)
7342                                 return null;
7343
7344                         if (Expr is Constant)
7345                                 return Expr;
7346
7347                         eclass = Expr.eclass;
7348                         type = Expr.Type;
7349                         return this;
7350                 }
7351
7352                 public override void Emit (EmitContext ec)
7353                 {
7354                         bool last_check = ec.CheckState;
7355                         bool last_const_check = ec.ConstantCheckState;
7356
7357                         ec.CheckState = false;
7358                         ec.ConstantCheckState = false;
7359                         Expr.Emit (ec);
7360                         ec.CheckState = last_check;
7361                         ec.ConstantCheckState = last_const_check;
7362                 }
7363
7364         }
7365
7366         /// <summary>
7367         ///   An Element Access expression.
7368         ///
7369         ///   During semantic analysis these are transformed into
7370         ///   IndexerAccess, ArrayAccess or a PointerArithmetic.
7371         /// </summary>
7372         public class ElementAccess : Expression {
7373                 public ArrayList  Arguments;
7374                 public Expression Expr;
7375
7376                 public ElementAccess (Expression e, ArrayList e_list, Location l)
7377                 {
7378                         Expr = e;
7379
7380                         loc  = l;
7381
7382                         if (e_list == null)
7383                                 return;
7384
7385                         Arguments = new ArrayList ();
7386                         foreach (Expression tmp in e_list)
7387                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
7388
7389                 }
7390
7391                 bool CommonResolve (EmitContext ec)
7392                 {
7393                         Expr = Expr.Resolve (ec);
7394
7395                         if (Expr == null)
7396                                 return false;
7397
7398                         if (Arguments == null)
7399                                 return false;
7400
7401                         foreach (Argument a in Arguments){
7402                                 if (!a.Resolve (ec, loc))
7403                                         return false;
7404                         }
7405
7406                         return true;
7407                 }
7408
7409                 Expression MakePointerAccess (EmitContext ec)
7410                 {
7411                         Type t = Expr.Type;
7412
7413                         if (t == TypeManager.void_ptr_type){
7414                                 Error (242, "The array index operation is not valid for void pointers");
7415                                 return null;
7416                         }
7417                         if (Arguments.Count != 1){
7418                                 Error (196, "A pointer must be indexed by a single value");
7419                                 return null;
7420                         }
7421                         Expression p;
7422
7423                         p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr, t, loc).Resolve (ec);
7424                         if (p == null)
7425                                 return null;
7426                         return new Indirection (p, loc).Resolve (ec);
7427                 }
7428
7429                 public override Expression DoResolve (EmitContext ec)
7430                 {
7431                         if (!CommonResolve (ec))
7432                                 return null;
7433
7434                         //
7435                         // We perform some simple tests, and then to "split" the emit and store
7436                         // code we create an instance of a different class, and return that.
7437                         //
7438                         // I am experimenting with this pattern.
7439                         //
7440                         Type t = Expr.Type;
7441
7442                         if (t == TypeManager.array_type){
7443                                 Report.Error (21, loc, "Cannot use indexer on System.Array");
7444                                 return null;
7445                         }
7446
7447                         if (t.IsArray)
7448                                 return (new ArrayAccess (this, loc)).Resolve (ec);
7449                         else if (t.IsPointer)
7450                                 return MakePointerAccess (ec);
7451                         else
7452                                 return (new IndexerAccess (this, loc)).Resolve (ec);
7453                 }
7454
7455                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7456                 {
7457                         if (!CommonResolve (ec))
7458                                 return null;
7459
7460                         Type t = Expr.Type;
7461                         if (t.IsArray)
7462                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
7463                         else if (t.IsPointer)
7464                                 return MakePointerAccess (ec);
7465                         else
7466                                 return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
7467                 }
7468
7469                 public override void Emit (EmitContext ec)
7470                 {
7471                         throw new Exception ("Should never be reached");
7472                 }
7473         }
7474
7475         /// <summary>
7476         ///   Implements array access
7477         /// </summary>
7478         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
7479                 //
7480                 // Points to our "data" repository
7481                 //
7482                 ElementAccess ea;
7483
7484                 LocalTemporary temp;
7485                 bool prepared;
7486
7487                 public ArrayAccess (ElementAccess ea_data, Location l)
7488                 {
7489                         ea = ea_data;
7490                         eclass = ExprClass.Variable;
7491                         loc = l;
7492                 }
7493
7494                 public override Expression DoResolve (EmitContext ec)
7495                 {
7496 #if false
7497                         ExprClass eclass = ea.Expr.eclass;
7498
7499                         // As long as the type is valid
7500                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
7501                               eclass == ExprClass.Value)) {
7502                                 ea.Expr.Error_UnexpectedKind ("variable or value");
7503                                 return null;
7504                         }
7505 #endif
7506
7507                         Type t = ea.Expr.Type;
7508                         if (t.GetArrayRank () != ea.Arguments.Count){
7509                                 ea.Error (22,
7510                                           "Incorrect number of indexes for array " +
7511                                           " expected: " + t.GetArrayRank () + " got: " +
7512                                           ea.Arguments.Count);
7513                                 return null;
7514                         }
7515
7516                         type = TypeManager.GetElementType (t);
7517                         if (type.IsPointer && !ec.InUnsafe){
7518                                 UnsafeError (ea.Location);
7519                                 return null;
7520                         }
7521
7522                         foreach (Argument a in ea.Arguments){
7523                                 Type argtype = a.Type;
7524
7525                                 if (argtype == TypeManager.int32_type ||
7526                                     argtype == TypeManager.uint32_type ||
7527                                     argtype == TypeManager.int64_type ||
7528                                     argtype == TypeManager.uint64_type)
7529                                         continue;
7530
7531                                 //
7532                                 // Mhm.  This is strage, because the Argument.Type is not the same as
7533                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
7534                                 //
7535                                 // Wonder if I will run into trouble for this.
7536                                 //
7537                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
7538                                 if (a.Expr == null)
7539                                         return null;
7540                         }
7541
7542                         eclass = ExprClass.Variable;
7543
7544                         return this;
7545                 }
7546
7547                 /// <summary>
7548                 ///    Emits the right opcode to load an object of Type `t'
7549                 ///    from an array of T
7550                 /// </summary>
7551                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
7552                 {
7553                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
7554                                 ig.Emit (OpCodes.Ldelem_U1);
7555                         else if (type == TypeManager.sbyte_type)
7556                                 ig.Emit (OpCodes.Ldelem_I1);
7557                         else if (type == TypeManager.short_type)
7558                                 ig.Emit (OpCodes.Ldelem_I2);
7559                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
7560                                 ig.Emit (OpCodes.Ldelem_U2);
7561                         else if (type == TypeManager.int32_type)
7562                                 ig.Emit (OpCodes.Ldelem_I4);
7563                         else if (type == TypeManager.uint32_type)
7564                                 ig.Emit (OpCodes.Ldelem_U4);
7565                         else if (type == TypeManager.uint64_type)
7566                                 ig.Emit (OpCodes.Ldelem_I8);
7567                         else if (type == TypeManager.int64_type)
7568                                 ig.Emit (OpCodes.Ldelem_I8);
7569                         else if (type == TypeManager.float_type)
7570                                 ig.Emit (OpCodes.Ldelem_R4);
7571                         else if (type == TypeManager.double_type)
7572                                 ig.Emit (OpCodes.Ldelem_R8);
7573                         else if (type == TypeManager.intptr_type)
7574                                 ig.Emit (OpCodes.Ldelem_I);
7575                         else if (TypeManager.IsEnumType (type)){
7576                                 EmitLoadOpcode (ig, TypeManager.EnumToUnderlying (type));
7577                         } else if (type.IsValueType){
7578                                 ig.Emit (OpCodes.Ldelema, type);
7579                                 ig.Emit (OpCodes.Ldobj, type);
7580                         } else
7581                                 ig.Emit (OpCodes.Ldelem_Ref);
7582                 }
7583
7584                 /// <summary>
7585                 ///    Returns the right opcode to store an object of Type `t'
7586                 ///    from an array of T.
7587                 /// </summary>
7588                 static public OpCode GetStoreOpcode (Type t, out bool is_stobj)
7589                 {
7590                         //Console.WriteLine (new System.Diagnostics.StackTrace ());
7591                         is_stobj = false;
7592                         t = TypeManager.TypeToCoreType (t);
7593                         if (TypeManager.IsEnumType (t))
7594                                 t = TypeManager.EnumToUnderlying (t);
7595                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
7596                             t == TypeManager.bool_type)
7597                                 return OpCodes.Stelem_I1;
7598                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type ||
7599                                  t == TypeManager.char_type)
7600                                 return OpCodes.Stelem_I2;
7601                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
7602                                 return OpCodes.Stelem_I4;
7603                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
7604                                 return OpCodes.Stelem_I8;
7605                         else if (t == TypeManager.float_type)
7606                                 return OpCodes.Stelem_R4;
7607                         else if (t == TypeManager.double_type)
7608                                 return OpCodes.Stelem_R8;
7609                         else if (t == TypeManager.intptr_type) {
7610                                 is_stobj = true;
7611                                 return OpCodes.Stobj;
7612                         } else if (t.IsValueType) {
7613                                 is_stobj = true;
7614                                 return OpCodes.Stobj;
7615                         } else
7616                                 return OpCodes.Stelem_Ref;
7617                 }
7618
7619                 MethodInfo FetchGetMethod ()
7620                 {
7621                         ModuleBuilder mb = CodeGen.Module.Builder;
7622                         int arg_count = ea.Arguments.Count;
7623                         Type [] args = new Type [arg_count];
7624                         MethodInfo get;
7625
7626                         for (int i = 0; i < arg_count; i++){
7627                                 //args [i++] = a.Type;
7628                                 args [i] = TypeManager.int32_type;
7629                         }
7630
7631                         get = mb.GetArrayMethod (
7632                                 ea.Expr.Type, "Get",
7633                                 CallingConventions.HasThis |
7634                                 CallingConventions.Standard,
7635                                 type, args);
7636                         return get;
7637                 }
7638
7639
7640                 MethodInfo FetchAddressMethod ()
7641                 {
7642                         ModuleBuilder mb = CodeGen.Module.Builder;
7643                         int arg_count = ea.Arguments.Count;
7644                         Type [] args = new Type [arg_count];
7645                         MethodInfo address;
7646                         Type ret_type;
7647
7648                         ret_type = TypeManager.GetReferenceType (type);
7649
7650                         for (int i = 0; i < arg_count; i++){
7651                                 //args [i++] = a.Type;
7652                                 args [i] = TypeManager.int32_type;
7653                         }
7654
7655                         address = mb.GetArrayMethod (
7656                                 ea.Expr.Type, "Address",
7657                                 CallingConventions.HasThis |
7658                                 CallingConventions.Standard,
7659                                 ret_type, args);
7660
7661                         return address;
7662                 }
7663
7664                 //
7665                 // Load the array arguments into the stack.
7666                 //
7667                 // If we have been requested to cache the values (cached_locations array
7668                 // initialized), then load the arguments the first time and store them
7669                 // in locals.  otherwise load from local variables.
7670                 //
7671                 void LoadArrayAndArguments (EmitContext ec)
7672                 {
7673                         ILGenerator ig = ec.ig;
7674
7675                         ea.Expr.Emit (ec);
7676                         foreach (Argument a in ea.Arguments){
7677                                 Type argtype = a.Expr.Type;
7678
7679                                 a.Expr.Emit (ec);
7680
7681                                 if (argtype == TypeManager.int64_type)
7682                                         ig.Emit (OpCodes.Conv_Ovf_I);
7683                                 else if (argtype == TypeManager.uint64_type)
7684                                         ig.Emit (OpCodes.Conv_Ovf_I_Un);
7685                         }
7686                 }
7687
7688                 public void Emit (EmitContext ec, bool leave_copy)
7689                 {
7690                         int rank = ea.Expr.Type.GetArrayRank ();
7691                         ILGenerator ig = ec.ig;
7692
7693                         if (!prepared) {
7694                                 LoadArrayAndArguments (ec);
7695
7696                                 if (rank == 1)
7697                                         EmitLoadOpcode (ig, type);
7698                                 else {
7699                                         MethodInfo method;
7700
7701                                         method = FetchGetMethod ();
7702                                         ig.Emit (OpCodes.Call, method);
7703                                 }
7704                         } else
7705                                 LoadFromPtr (ec.ig, this.type);
7706
7707                         if (leave_copy) {
7708                                 ec.ig.Emit (OpCodes.Dup);
7709                                 temp = new LocalTemporary (ec, this.type);
7710                                 temp.Store (ec);
7711                         }
7712                 }
7713
7714                 public override void Emit (EmitContext ec)
7715                 {
7716                         Emit (ec, false);
7717                 }
7718
7719                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
7720                 {
7721                         int rank = ea.Expr.Type.GetArrayRank ();
7722                         ILGenerator ig = ec.ig;
7723                         Type t = source.Type;
7724                         prepared = prepare_for_load;
7725
7726                         if (prepare_for_load) {
7727                                 AddressOf (ec, AddressOp.LoadStore);
7728                                 ec.ig.Emit (OpCodes.Dup);
7729                                 source.Emit (ec);
7730                                 if (leave_copy) {
7731                                         ec.ig.Emit (OpCodes.Dup);
7732                                         temp = new LocalTemporary (ec, this.type);
7733                                         temp.Store (ec);
7734                                 }
7735                                 StoreFromPtr (ec.ig, t);
7736
7737                                 if (temp != null)
7738                                         temp.Emit (ec);
7739
7740                                 return;
7741                         }
7742
7743                         LoadArrayAndArguments (ec);
7744
7745                         if (rank == 1) {
7746                                 bool is_stobj;
7747                                 OpCode op = GetStoreOpcode (t, out is_stobj);
7748                                 //
7749                                 // The stobj opcode used by value types will need
7750                                 // an address on the stack, not really an array/array
7751                                 // pair
7752                                 //
7753                                 if (is_stobj)
7754                                         ig.Emit (OpCodes.Ldelema, t);
7755
7756                                 source.Emit (ec);
7757                                 if (leave_copy) {
7758                                         ec.ig.Emit (OpCodes.Dup);
7759                                         temp = new LocalTemporary (ec, this.type);
7760                                         temp.Store (ec);
7761                                 }
7762
7763                                 if (is_stobj)
7764                                         ig.Emit (OpCodes.Stobj, t);
7765                                 else
7766                                         ig.Emit (op);
7767                         } else {
7768                                 ModuleBuilder mb = CodeGen.Module.Builder;
7769                                 int arg_count = ea.Arguments.Count;
7770                                 Type [] args = new Type [arg_count + 1];
7771                                 MethodInfo set;
7772
7773                                 source.Emit (ec);
7774                                 if (leave_copy) {
7775                                         ec.ig.Emit (OpCodes.Dup);
7776                                         temp = new LocalTemporary (ec, this.type);
7777                                         temp.Store (ec);
7778                                 }
7779
7780                                 for (int i = 0; i < arg_count; i++){
7781                                         //args [i++] = a.Type;
7782                                         args [i] = TypeManager.int32_type;
7783                                 }
7784
7785                                 args [arg_count] = type;
7786
7787                                 set = mb.GetArrayMethod (
7788                                         ea.Expr.Type, "Set",
7789                                         CallingConventions.HasThis |
7790                                         CallingConventions.Standard,
7791                                         TypeManager.void_type, args);
7792
7793                                 ig.Emit (OpCodes.Call, set);
7794                         }
7795
7796                         if (temp != null)
7797                                 temp.Emit (ec);
7798                 }
7799
7800                 public void AddressOf (EmitContext ec, AddressOp mode)
7801                 {
7802                         int rank = ea.Expr.Type.GetArrayRank ();
7803                         ILGenerator ig = ec.ig;
7804
7805                         LoadArrayAndArguments (ec);
7806
7807                         if (rank == 1){
7808                                 ig.Emit (OpCodes.Ldelema, type);
7809                         } else {
7810                                 MethodInfo address = FetchAddressMethod ();
7811                                 ig.Emit (OpCodes.Call, address);
7812                         }
7813                 }
7814         }
7815
7816
7817         class Indexers {
7818                 public ArrayList Properties;
7819                 static Hashtable map;
7820
7821                 public struct Indexer {
7822                         public readonly Type Type;
7823                         public readonly MethodInfo Getter, Setter;
7824
7825                         public Indexer (Type type, MethodInfo get, MethodInfo set)
7826                         {
7827                                 this.Type = type;
7828                                 this.Getter = get;
7829                                 this.Setter = set;
7830                         }
7831                 }
7832
7833                 static Indexers ()
7834                 {
7835                         map = new Hashtable ();
7836                 }
7837
7838                 Indexers ()
7839                 {
7840                         Properties = new ArrayList ();
7841                 }
7842
7843                 void Append (MemberInfo [] mi)
7844                 {
7845                         foreach (PropertyInfo property in mi){
7846                                 MethodInfo get, set;
7847
7848                                 get = property.GetGetMethod (true);
7849                                 set = property.GetSetMethod (true);
7850                                 Properties.Add (new Indexer (property.PropertyType, get, set));
7851                         }
7852                 }
7853
7854                 static private MemberInfo [] GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
7855                 {
7856                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
7857
7858                         MemberInfo [] mi = TypeManager.MemberLookup (
7859                                 caller_type, caller_type, lookup_type, MemberTypes.Property,
7860                                 BindingFlags.Public | BindingFlags.Instance |
7861                                 BindingFlags.DeclaredOnly, p_name, null);
7862
7863                         if (mi == null || mi.Length == 0)
7864                                 return null;
7865
7866                         return mi;
7867                 }
7868
7869                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
7870                 {
7871                         Indexers ix = (Indexers) map [lookup_type];
7872
7873                         if (ix != null)
7874                                 return ix;
7875
7876                         Type copy = lookup_type;
7877                         while (copy != TypeManager.object_type && copy != null){
7878                                 MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, copy);
7879
7880                                 if (mi != null){
7881                                         if (ix == null)
7882                                                 ix = new Indexers ();
7883
7884                                         ix.Append (mi);
7885                                 }
7886
7887                                 copy = copy.BaseType;
7888                         }
7889
7890                         if (!lookup_type.IsInterface)
7891                                 return ix;
7892
7893                         TypeExpr [] ifaces = TypeManager.GetInterfaces (lookup_type);
7894                         if (ifaces != null) {
7895                                 foreach (TypeExpr iface in ifaces) {
7896                                         Type itype = iface.Type;
7897                                         MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, itype);
7898                                         if (mi != null){
7899                                                 if (ix == null)
7900                                                         ix = new Indexers ();
7901
7902                                                 ix.Append (mi);
7903                                         }
7904                                 }
7905                         }
7906
7907                         return ix;
7908                 }
7909         }
7910
7911         /// <summary>
7912         ///   Expressions that represent an indexer call.
7913         /// </summary>
7914         public class IndexerAccess : Expression, IAssignMethod {
7915                 //
7916                 // Points to our "data" repository
7917                 //
7918                 MethodInfo get, set;
7919                 ArrayList set_arguments;
7920                 bool is_base_indexer;
7921
7922                 protected Type indexer_type;
7923                 protected Type current_type;
7924                 protected Expression instance_expr;
7925                 protected ArrayList arguments;
7926
7927                 public IndexerAccess (ElementAccess ea, Location loc)
7928                         : this (ea.Expr, false, loc)
7929                 {
7930                         this.arguments = ea.Arguments;
7931                 }
7932
7933                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
7934                                          Location loc)
7935                 {
7936                         this.instance_expr = instance_expr;
7937                         this.is_base_indexer = is_base_indexer;
7938                         this.eclass = ExprClass.Value;
7939                         this.loc = loc;
7940                 }
7941
7942                 protected virtual bool CommonResolve (EmitContext ec)
7943                 {
7944                         indexer_type = instance_expr.Type;
7945                         current_type = ec.ContainerType;
7946
7947                         return true;
7948                 }
7949
7950                 public override Expression DoResolve (EmitContext ec)
7951                 {
7952                         ArrayList AllGetters = new ArrayList();
7953                         if (!CommonResolve (ec))
7954                                 return null;
7955
7956                         //
7957                         // Step 1: Query for all `Item' *properties*.  Notice
7958                         // that the actual methods are pointed from here.
7959                         //
7960                         // This is a group of properties, piles of them.
7961
7962                         bool found_any = false, found_any_getters = false;
7963                         Type lookup_type = indexer_type;
7964
7965                         Indexers ilist;
7966                         ilist = Indexers.GetIndexersForType (current_type, lookup_type, loc);
7967                         if (ilist != null) {
7968                                 found_any = true;
7969                                 if (ilist.Properties != null) {
7970                                         foreach (Indexers.Indexer ix in ilist.Properties) {
7971                                                 if (ix.Getter != null)
7972                                                         AllGetters.Add(ix.Getter);
7973                                         }
7974                                 }
7975                         }
7976
7977                         if (AllGetters.Count > 0) {
7978                                 found_any_getters = true;
7979                                 get = (MethodInfo) Invocation.OverloadResolve (
7980                                         ec, new MethodGroupExpr (AllGetters, loc),
7981                                         arguments, false, loc);
7982                         }
7983
7984                         if (!found_any) {
7985                                 Report.Error (21, loc,
7986                                               "Type `" + TypeManager.CSharpName (indexer_type) +
7987                                               "' does not have any indexers defined");
7988                                 return null;
7989                         }
7990
7991                         if (!found_any_getters) {
7992                                 Error (154, "indexer can not be used in this context, because " +
7993                                        "it lacks a `get' accessor");
7994                                 return null;
7995                         }
7996
7997                         if (get == null) {
7998                                 Error (1501, "No Overload for method `this' takes `" +
7999                                        arguments.Count + "' arguments");
8000                                 return null;
8001                         }
8002
8003                         //
8004                         // Only base will allow this invocation to happen.
8005                         //
8006                         if (get.IsAbstract && this is BaseIndexerAccess){
8007                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (get));
8008                                 return null;
8009                         }
8010
8011                         type = get.ReturnType;
8012                         if (type.IsPointer && !ec.InUnsafe){
8013                                 UnsafeError (loc);
8014                                 return null;
8015                         }
8016
8017                         eclass = ExprClass.IndexerAccess;
8018                         return this;
8019                 }
8020
8021                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8022                 {
8023                         ArrayList AllSetters = new ArrayList();
8024                         if (!CommonResolve (ec))
8025                                 return null;
8026
8027                         bool found_any = false, found_any_setters = false;
8028
8029                         Indexers ilist = Indexers.GetIndexersForType (current_type, indexer_type, loc);
8030                         if (ilist != null) {
8031                                 found_any = true;
8032                                 if (ilist.Properties != null) {
8033                                         foreach (Indexers.Indexer ix in ilist.Properties) {
8034                                                 if (ix.Setter != null)
8035                                                         AllSetters.Add(ix.Setter);
8036                                         }
8037                                 }
8038                         }
8039                         if (AllSetters.Count > 0) {
8040                                 found_any_setters = true;
8041                                 set_arguments = (ArrayList) arguments.Clone ();
8042                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
8043                                 set = (MethodInfo) Invocation.OverloadResolve (
8044                                         ec, new MethodGroupExpr (AllSetters, loc),
8045                                         set_arguments, false, loc);
8046                         }
8047
8048                         if (!found_any) {
8049                                 Report.Error (21, loc,
8050                                               "Type `" + TypeManager.CSharpName (indexer_type) +
8051                                               "' does not have any indexers defined");
8052                                 return null;
8053                         }
8054
8055                         if (!found_any_setters) {
8056                                 Error (154, "indexer can not be used in this context, because " +
8057                                        "it lacks a `set' accessor");
8058                                 return null;
8059                         }
8060
8061                         if (set == null) {
8062                                 Error (1501, "No Overload for method `this' takes `" +
8063                                        arguments.Count + "' arguments");
8064                                 return null;
8065                         }
8066
8067                         //
8068                         // Only base will allow this invocation to happen.
8069                         //
8070                         if (set.IsAbstract && this is BaseIndexerAccess){
8071                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (set));
8072                                 return null;
8073                         }
8074
8075                         //
8076                         // Now look for the actual match in the list of indexers to set our "return" type
8077                         //
8078                         type = TypeManager.void_type;   // default value
8079                         foreach (Indexers.Indexer ix in ilist.Properties){
8080                                 if (ix.Setter == set){
8081                                         type = ix.Type;
8082                                         break;
8083                                 }
8084                         }
8085
8086                         eclass = ExprClass.IndexerAccess;
8087                         return this;
8088                 }
8089
8090                 bool prepared = false;
8091                 LocalTemporary temp;
8092
8093                 public void Emit (EmitContext ec, bool leave_copy)
8094                 {
8095                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, get, arguments, loc, prepared, false);
8096                         if (leave_copy) {
8097                                 ec.ig.Emit (OpCodes.Dup);
8098                                 temp = new LocalTemporary (ec, Type);
8099                                 temp.Store (ec);
8100                         }
8101                 }
8102
8103                 //
8104                 // source is ignored, because we already have a copy of it from the
8105                 // LValue resolution and we have already constructed a pre-cached
8106                 // version of the arguments (ea.set_arguments);
8107                 //
8108                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8109                 {
8110                         prepared = prepare_for_load;
8111                         Argument a = (Argument) set_arguments [set_arguments.Count - 1];
8112
8113                         if (prepared) {
8114                                 source.Emit (ec);
8115                                 if (leave_copy) {
8116                                         ec.ig.Emit (OpCodes.Dup);
8117                                         temp = new LocalTemporary (ec, Type);
8118                                         temp.Store (ec);
8119                                 }
8120                         } else if (leave_copy) {
8121                                 temp = new LocalTemporary (ec, Type);
8122                                 source.Emit (ec);
8123                                 temp.Store (ec);
8124                                 a.Expr = temp;
8125                         }
8126
8127                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, set, set_arguments, loc, false, prepared);
8128
8129                         if (temp != null)
8130                                 temp.Emit (ec);
8131                 }
8132
8133
8134                 public override void Emit (EmitContext ec)
8135                 {
8136                         Emit (ec, false);
8137                 }
8138         }
8139
8140         /// <summary>
8141         ///   The base operator for method names
8142         /// </summary>
8143         public class BaseAccess : Expression {
8144                 string member;
8145
8146                 public BaseAccess (string member, Location l)
8147                 {
8148                         this.member = member;
8149                         loc = l;
8150                 }
8151
8152                 public override Expression DoResolve (EmitContext ec)
8153                 {
8154                         Expression c = CommonResolve (ec);
8155
8156                         if (c == null)
8157                                 return null;
8158
8159                         //
8160                         // MethodGroups use this opportunity to flag an error on lacking ()
8161                         //
8162                         if (!(c is MethodGroupExpr))
8163                                 return c.Resolve (ec);
8164                         return c;
8165                 }
8166
8167                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8168                 {
8169                         Expression c = CommonResolve (ec);
8170
8171                         if (c == null)
8172                                 return null;
8173
8174                         //
8175                         // MethodGroups use this opportunity to flag an error on lacking ()
8176                         //
8177                         if (! (c is MethodGroupExpr))
8178                                 return c.DoResolveLValue (ec, right_side);
8179
8180                         return c;
8181                 }
8182
8183                 Expression CommonResolve (EmitContext ec)
8184                 {
8185                         Expression member_lookup;
8186                         Type current_type = ec.ContainerType;
8187                         Type base_type = current_type.BaseType;
8188                         Expression e;
8189
8190                         if (ec.IsStatic){
8191                                 Error (1511, "Keyword base is not allowed in static method");
8192                                 return null;
8193                         }
8194
8195                         if (ec.IsFieldInitializer){
8196                                 Error (1512, "Keyword base is not available in the current context");
8197                                 return null;
8198                         }
8199
8200                         member_lookup = MemberLookup (ec, ec.ContainerType, null, base_type, member,
8201                                                       AllMemberTypes, AllBindingFlags, loc);
8202                         if (member_lookup == null) {
8203                                 MemberLookupFailed (ec, base_type, base_type, member, null, loc);
8204                                 return null;
8205                         }
8206
8207                         Expression left;
8208
8209                         if (ec.IsStatic)
8210                                 left = new TypeExpression (base_type, loc);
8211                         else
8212                                 left = ec.GetThis (loc);
8213
8214                         e = MemberAccess.ResolveMemberAccess (ec, member_lookup, left, loc, null);
8215
8216                         if (e is PropertyExpr){
8217                                 PropertyExpr pe = (PropertyExpr) e;
8218
8219                                 pe.IsBase = true;
8220                         }
8221
8222                         if (e is MethodGroupExpr)
8223                                 ((MethodGroupExpr) e).IsBase = true;
8224
8225                         return e;
8226                 }
8227
8228                 public override void Emit (EmitContext ec)
8229                 {
8230                         throw new Exception ("Should never be called");
8231                 }
8232         }
8233
8234         /// <summary>
8235         ///   The base indexer operator
8236         /// </summary>
8237         public class BaseIndexerAccess : IndexerAccess {
8238                 public BaseIndexerAccess (ArrayList args, Location loc)
8239                         : base (null, true, loc)
8240                 {
8241                         arguments = new ArrayList ();
8242                         foreach (Expression tmp in args)
8243                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
8244                 }
8245
8246                 protected override bool CommonResolve (EmitContext ec)
8247                 {
8248                         instance_expr = ec.GetThis (loc);
8249
8250                         current_type = ec.ContainerType.BaseType;
8251                         indexer_type = current_type;
8252
8253                         foreach (Argument a in arguments){
8254                                 if (!a.Resolve (ec, loc))
8255                                         return false;
8256                         }
8257
8258                         return true;
8259                 }
8260         }
8261
8262         /// <summary>
8263         ///   This class exists solely to pass the Type around and to be a dummy
8264         ///   that can be passed to the conversion functions (this is used by
8265         ///   foreach implementation to typecast the object return value from
8266         ///   get_Current into the proper type.  All code has been generated and
8267         ///   we only care about the side effect conversions to be performed
8268         ///
8269         ///   This is also now used as a placeholder where a no-action expression
8270         ///   is needed (the `New' class).
8271         /// </summary>
8272         public class EmptyExpression : Expression {
8273                 public EmptyExpression ()
8274                 {
8275                         type = TypeManager.object_type;
8276                         eclass = ExprClass.Value;
8277                         loc = Location.Null;
8278                 }
8279
8280                 public EmptyExpression (Type t)
8281                 {
8282                         type = t;
8283                         eclass = ExprClass.Value;
8284                         loc = Location.Null;
8285                 }
8286
8287                 public override Expression DoResolve (EmitContext ec)
8288                 {
8289                         return this;
8290                 }
8291
8292                 public override void Emit (EmitContext ec)
8293                 {
8294                         // nothing, as we only exist to not do anything.
8295                 }
8296
8297                 //
8298                 // This is just because we might want to reuse this bad boy
8299                 // instead of creating gazillions of EmptyExpressions.
8300                 // (CanImplicitConversion uses it)
8301                 //
8302                 public void SetType (Type t)
8303                 {
8304                         type = t;
8305                 }
8306         }
8307
8308         public class UserCast : Expression {
8309                 MethodBase method;
8310                 Expression source;
8311
8312                 public UserCast (MethodInfo method, Expression source, Location l)
8313                 {
8314                         this.method = method;
8315                         this.source = source;
8316                         type = method.ReturnType;
8317                         eclass = ExprClass.Value;
8318                         loc = l;
8319                 }
8320
8321                 public override Expression DoResolve (EmitContext ec)
8322                 {
8323                         //
8324                         // We are born fully resolved
8325                         //
8326                         return this;
8327                 }
8328
8329                 public override void Emit (EmitContext ec)
8330                 {
8331                         ILGenerator ig = ec.ig;
8332
8333                         source.Emit (ec);
8334
8335                         if (method is MethodInfo)
8336                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
8337                         else
8338                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
8339
8340                 }
8341         }
8342
8343         // <summary>
8344         //   This class is used to "construct" the type during a typecast
8345         //   operation.  Since the Type.GetType class in .NET can parse
8346         //   the type specification, we just use this to construct the type
8347         //   one bit at a time.
8348         // </summary>
8349         public class ComposedCast : TypeExpr {
8350                 Expression left;
8351                 string dim;
8352
8353                 public ComposedCast (Expression left, string dim, Location l)
8354                 {
8355                         this.left = left;
8356                         this.dim = dim;
8357                         loc = l;
8358                 }
8359
8360                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
8361                 {
8362                         Type ltype = ec.DeclSpace.ResolveType (left, false, loc);
8363                         if (ltype == null)
8364                                 return null;
8365
8366                         if ((ltype == TypeManager.void_type) && (dim != "*")) {
8367                                 Report.Error (1547, Location,
8368                                               "Keyword 'void' cannot be used in this context");
8369                                 return null;
8370                         }
8371
8372                         //
8373                         // ltype.Fullname is already fully qualified, so we can skip
8374                         // a lot of probes, and go directly to TypeManager.LookupType
8375                         //
8376                         string cname = ltype.FullName + dim;
8377                         type = TypeManager.LookupTypeDirect (cname);
8378                         if (type == null){
8379                                 //
8380                                 // For arrays of enumerations we are having a problem
8381                                 // with the direct lookup.  Need to investigate.
8382                                 //
8383                                 // For now, fall back to the full lookup in that case.
8384                                 //
8385                                 type = RootContext.LookupType (
8386                                         ec.DeclSpace, cname, false, loc);
8387
8388                                 if (type == null)
8389                                         return null;
8390                         }
8391
8392                         if (!ec.ResolvingTypeTree){
8393                                 //
8394                                 // If the above flag is set, this is being invoked from the ResolveType function.
8395                                 // Upper layers take care of the type validity in this context.
8396                                 //
8397                         if (!ec.InUnsafe && type.IsPointer){
8398                                 UnsafeError (loc);
8399                                 return null;
8400                         }
8401                         }
8402
8403                         eclass = ExprClass.Type;
8404                         return this;
8405                 }
8406
8407                 public override string Name {
8408                         get {
8409                                 return left + dim;
8410                         }
8411                 }
8412         }
8413
8414         //
8415         // This class is used to represent the address of an array, used
8416         // only by the Fixed statement, this is like the C "&a [0]" construct.
8417         //
8418         public class ArrayPtr : Expression {
8419                 Expression array;
8420
8421                 public ArrayPtr (Expression array, Location l)
8422                 {
8423                         Type array_type = TypeManager.GetElementType (array.Type);
8424
8425                         this.array = array;
8426
8427                         type = TypeManager.GetPointerType (array_type);
8428                         eclass = ExprClass.Value;
8429                         loc = l;
8430                 }
8431
8432                 public override void Emit (EmitContext ec)
8433                 {
8434                         ILGenerator ig = ec.ig;
8435
8436                         array.Emit (ec);
8437                         IntLiteral.EmitInt (ig, 0);
8438                         ig.Emit (OpCodes.Ldelema, TypeManager.GetElementType (array.Type));
8439                 }
8440
8441                 public override Expression DoResolve (EmitContext ec)
8442                 {
8443                         //
8444                         // We are born fully resolved
8445                         //
8446                         return this;
8447                 }
8448         }
8449
8450         //
8451         // Used by the fixed statement
8452         //
8453         public class StringPtr : Expression {
8454                 LocalBuilder b;
8455
8456                 public StringPtr (LocalBuilder b, Location l)
8457                 {
8458                         this.b = b;
8459                         eclass = ExprClass.Value;
8460                         type = TypeManager.char_ptr_type;
8461                         loc = l;
8462                 }
8463
8464                 public override Expression DoResolve (EmitContext ec)
8465                 {
8466                         // This should never be invoked, we are born in fully
8467                         // initialized state.
8468
8469                         return this;
8470                 }
8471
8472                 public override void Emit (EmitContext ec)
8473                 {
8474                         ILGenerator ig = ec.ig;
8475
8476                         ig.Emit (OpCodes.Ldloc, b);
8477                         ig.Emit (OpCodes.Conv_I);
8478                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
8479                         ig.Emit (OpCodes.Add);
8480                 }
8481         }
8482
8483         //
8484         // Implements the `stackalloc' keyword
8485         //
8486         public class StackAlloc : Expression {
8487                 Type otype;
8488                 Expression t;
8489                 Expression count;
8490
8491                 public StackAlloc (Expression type, Expression count, Location l)
8492                 {
8493                         t = type;
8494                         this.count = count;
8495                         loc = l;
8496                 }
8497
8498                 public override Expression DoResolve (EmitContext ec)
8499                 {
8500                         count = count.Resolve (ec);
8501                         if (count == null)
8502                                 return null;
8503
8504                         if (count.Type != TypeManager.int32_type){
8505                                 count = Convert.ImplicitConversionRequired (ec, count, TypeManager.int32_type, loc);
8506                                 if (count == null)
8507                                         return null;
8508                         }
8509
8510                         Constant c = count as Constant;
8511                         // TODO: because we don't have property IsNegative
8512                         if (c != null && c.ConvertToUInt () == null) {
8513                                 Report.Error (247, loc, "Cannot use a negative size with stackalloc");
8514                                 return null;
8515                         }
8516
8517                         if (ec.CurrentBranching.InCatch () ||
8518                             ec.CurrentBranching.InFinally (true)) {
8519                                 Error (255,
8520                                        "stackalloc can not be used in a catch or finally block");
8521                                 return null;
8522                         }
8523
8524                         otype = ec.DeclSpace.ResolveType (t, false, loc);
8525
8526                         if (otype == null)
8527                                 return null;
8528
8529                         if (!TypeManager.VerifyUnManaged (otype, loc))
8530                                 return null;
8531
8532                         type = TypeManager.GetPointerType (otype);
8533                         eclass = ExprClass.Value;
8534
8535                         return this;
8536                 }
8537
8538                 public override void Emit (EmitContext ec)
8539                 {
8540                         int size = GetTypeSize (otype);
8541                         ILGenerator ig = ec.ig;
8542
8543                         if (size == 0)
8544                                 ig.Emit (OpCodes.Sizeof, otype);
8545                         else
8546                                 IntConstant.EmitInt (ig, size);
8547                         count.Emit (ec);
8548                         ig.Emit (OpCodes.Mul);
8549                         ig.Emit (OpCodes.Localloc);
8550                 }
8551         }
8552 }