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                 void Error_NegativeArrayIndex ()
5975                 {
5976                         Error (284, "Can not create array with a negative size");
5977                 }
5978
5979                 //
5980                 // Converts `source' to an int, uint, long or ulong.
5981                 //
5982                 Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
5983                 {
5984                         Expression target;
5985
5986                         bool old_checked = ec.CheckState;
5987                         ec.CheckState = true;
5988
5989                         target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
5990                         if (target == null){
5991                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
5992                                 if (target == null){
5993                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
5994                                         if (target == null){
5995                                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
5996                                                 if (target == null)
5997                                                         Convert.Error_CannotImplicitConversion (loc, source.Type, TypeManager.int32_type);
5998                                         }
5999                                 }
6000                         }
6001                         ec.CheckState = old_checked;
6002
6003                         //
6004                         // Only positive constants are allowed at compile time
6005                         //
6006                         if (target is Constant){
6007                                 if (target is IntConstant){
6008                                         if (((IntConstant) target).Value < 0){
6009                                                 Error_NegativeArrayIndex ();
6010                                                 return null;
6011                                         }
6012                                 }
6013
6014                                 if (target is LongConstant){
6015                                         if (((LongConstant) target).Value < 0){
6016                                                 Error_NegativeArrayIndex ();
6017                                                 return null;
6018                                         }
6019                                 }
6020
6021                         }
6022
6023                         return target;
6024                 }
6025
6026                 //
6027                 // Creates the type of the array
6028                 //
6029                 bool LookupType (EmitContext ec)
6030                 {
6031                         StringBuilder array_qualifier = new StringBuilder (rank);
6032
6033                         //
6034                         // `In the first form allocates an array instace of the type that results
6035                         // from deleting each of the individual expression from the expression list'
6036                         //
6037                         if (num_arguments > 0) {
6038                                 array_qualifier.Append ("[");
6039                                 for (int i = num_arguments-1; i > 0; i--)
6040                                         array_qualifier.Append (",");
6041                                 array_qualifier.Append ("]");
6042                         }
6043
6044                         //
6045                         // Lookup the type
6046                         //
6047                         Expression array_type_expr;
6048                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
6049                         type = ec.DeclSpace.ResolveType (array_type_expr, false, loc);
6050
6051                         if (type == null)
6052                                 return false;
6053
6054                         if (!type.IsArray) {
6055                                 Error (622, "Can only use array initializer expressions to assign to array types. Try using a new expression instead.");
6056                                 return false;
6057                         }
6058                         underlying_type = TypeManager.GetElementType (type);
6059                         dimensions = type.GetArrayRank ();
6060
6061                         return true;
6062                 }
6063
6064                 public override Expression DoResolve (EmitContext ec)
6065                 {
6066                         int arg_count;
6067
6068                         if (!LookupType (ec))
6069                                 return null;
6070
6071                         //
6072                         // First step is to validate the initializers and fill
6073                         // in any missing bits
6074                         //
6075                         if (!ValidateInitializers (ec, type))
6076                                 return null;
6077
6078                         if (arguments == null)
6079                                 arg_count = 0;
6080                         else {
6081                                 arg_count = arguments.Count;
6082                                 foreach (Argument a in arguments){
6083                                         if (!a.Resolve (ec, loc))
6084                                                 return null;
6085
6086                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
6087                                         if (real_arg == null)
6088                                                 return null;
6089
6090                                         a.Expr = real_arg;
6091                                 }
6092                         }
6093
6094                         array_element_type = TypeManager.GetElementType (type);
6095
6096                         if (array_element_type.IsAbstract && array_element_type.IsSealed) {
6097                                 Report.Error (719, loc, "'{0}': array elements cannot be of static type", TypeManager.CSharpName (array_element_type));
6098                                 return null;
6099                         }
6100
6101                         if (arg_count == 1) {
6102                                 is_one_dimensional = true;
6103                                 eclass = ExprClass.Value;
6104                                 return this;
6105                         }
6106
6107                         is_builtin_type = TypeManager.IsBuiltinType (type);
6108
6109                         if (is_builtin_type) {
6110                                 Expression ml;
6111
6112                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
6113                                                    AllBindingFlags, loc);
6114
6115                                 if (!(ml is MethodGroupExpr)) {
6116                                         ml.Error_UnexpectedKind ("method group");
6117                                         return null;
6118                                 }
6119
6120                                 if (ml == null) {
6121                                         Error (-6, "New invocation: Can not find a constructor for " +
6122                                                       "this argument list");
6123                                         return null;
6124                                 }
6125
6126                                 new_method = Invocation.OverloadResolve (
6127                                         ec, (MethodGroupExpr) ml, arguments, false, loc);
6128
6129                                 if (new_method == null) {
6130                                         Error (-6, "New invocation: Can not find a constructor for " +
6131                                                       "this argument list");
6132                                         return null;
6133                                 }
6134
6135                                 eclass = ExprClass.Value;
6136                                 return this;
6137                         } else {
6138                                 ModuleBuilder mb = CodeGen.Module.Builder;
6139                                 ArrayList args = new ArrayList ();
6140
6141                                 if (arguments != null) {
6142                                         for (int i = 0; i < arg_count; i++)
6143                                                 args.Add (TypeManager.int32_type);
6144                                 }
6145
6146                                 Type [] arg_types = null;
6147
6148                                 if (args.Count > 0)
6149                                         arg_types = new Type [args.Count];
6150
6151                                 args.CopyTo (arg_types, 0);
6152
6153                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
6154                                                             arg_types);
6155
6156                                 if (new_method == null) {
6157                                         Error (-6, "New invocation: Can not find a constructor for " +
6158                                                       "this argument list");
6159                                         return null;
6160                                 }
6161
6162                                 eclass = ExprClass.Value;
6163                                 return this;
6164                         }
6165                 }
6166
6167                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
6168                 {
6169                         int factor;
6170                         byte [] data;
6171                         byte [] element;
6172                         int count = array_data.Count;
6173
6174                         if (underlying_type.IsEnum)
6175                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
6176
6177                         factor = GetTypeSize (underlying_type);
6178                         if (factor == 0)
6179                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
6180
6181                         data = new byte [(count * factor + 4) & ~3];
6182                         int idx = 0;
6183
6184                         for (int i = 0; i < count; ++i) {
6185                                 object v = array_data [i];
6186
6187                                 if (v is EnumConstant)
6188                                         v = ((EnumConstant) v).Child;
6189
6190                                 if (v is Constant && !(v is StringConstant))
6191                                         v = ((Constant) v).GetValue ();
6192                                 else {
6193                                         idx += factor;
6194                                         continue;
6195                                 }
6196
6197                                 if (underlying_type == TypeManager.int64_type){
6198                                         if (!(v is Expression)){
6199                                                 long val = (long) v;
6200
6201                                                 for (int j = 0; j < factor; ++j) {
6202                                                         data [idx + j] = (byte) (val & 0xFF);
6203                                                         val = (val >> 8);
6204                                                 }
6205                                         }
6206                                 } else if (underlying_type == TypeManager.uint64_type){
6207                                         if (!(v is Expression)){
6208                                                 ulong val = (ulong) v;
6209
6210                                                 for (int j = 0; j < factor; ++j) {
6211                                                         data [idx + j] = (byte) (val & 0xFF);
6212                                                         val = (val >> 8);
6213                                                 }
6214                                         }
6215                                 } else if (underlying_type == TypeManager.float_type) {
6216                                         if (!(v is Expression)){
6217                                                 element = BitConverter.GetBytes ((float) v);
6218
6219                                                 for (int j = 0; j < factor; ++j)
6220                                                         data [idx + j] = element [j];
6221                                         }
6222                                 } else if (underlying_type == TypeManager.double_type) {
6223                                         if (!(v is Expression)){
6224                                                 element = BitConverter.GetBytes ((double) v);
6225
6226                                                 for (int j = 0; j < factor; ++j)
6227                                                         data [idx + j] = element [j];
6228                                         }
6229                                 } else if (underlying_type == TypeManager.char_type){
6230                                         if (!(v is Expression)){
6231                                                 int val = (int) ((char) v);
6232
6233                                                 data [idx] = (byte) (val & 0xff);
6234                                                 data [idx+1] = (byte) (val >> 8);
6235                                         }
6236                                 } else if (underlying_type == TypeManager.short_type){
6237                                         if (!(v is Expression)){
6238                                                 int val = (int) ((short) v);
6239
6240                                                 data [idx] = (byte) (val & 0xff);
6241                                                 data [idx+1] = (byte) (val >> 8);
6242                                         }
6243                                 } else if (underlying_type == TypeManager.ushort_type){
6244                                         if (!(v is Expression)){
6245                                                 int val = (int) ((ushort) v);
6246
6247                                                 data [idx] = (byte) (val & 0xff);
6248                                                 data [idx+1] = (byte) (val >> 8);
6249                                         }
6250                                 } else if (underlying_type == TypeManager.int32_type) {
6251                                         if (!(v is Expression)){
6252                                                 int val = (int) v;
6253
6254                                                 data [idx]   = (byte) (val & 0xff);
6255                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6256                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6257                                                 data [idx+3] = (byte) (val >> 24);
6258                                         }
6259                                 } else if (underlying_type == TypeManager.uint32_type) {
6260                                         if (!(v is Expression)){
6261                                                 uint val = (uint) v;
6262
6263                                                 data [idx]   = (byte) (val & 0xff);
6264                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6265                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6266                                                 data [idx+3] = (byte) (val >> 24);
6267                                         }
6268                                 } else if (underlying_type == TypeManager.sbyte_type) {
6269                                         if (!(v is Expression)){
6270                                                 sbyte val = (sbyte) v;
6271                                                 data [idx] = (byte) val;
6272                                         }
6273                                 } else if (underlying_type == TypeManager.byte_type) {
6274                                         if (!(v is Expression)){
6275                                                 byte val = (byte) v;
6276                                                 data [idx] = (byte) val;
6277                                         }
6278                                 } else if (underlying_type == TypeManager.bool_type) {
6279                                         if (!(v is Expression)){
6280                                                 bool val = (bool) v;
6281                                                 data [idx] = (byte) (val ? 1 : 0);
6282                                         }
6283                                 } else if (underlying_type == TypeManager.decimal_type){
6284                                         if (!(v is Expression)){
6285                                                 int [] bits = Decimal.GetBits ((decimal) v);
6286                                                 int p = idx;
6287
6288                                                 // FIXME: For some reason, this doesn't work on the MS runtime.
6289                                                 int [] nbits = new int [4];
6290                                                 nbits [0] = bits [3];
6291                                                 nbits [1] = bits [2];
6292                                                 nbits [2] = bits [0];
6293                                                 nbits [3] = bits [1];
6294
6295                                                 for (int j = 0; j < 4; j++){
6296                                                         data [p++] = (byte) (nbits [j] & 0xff);
6297                                                         data [p++] = (byte) ((nbits [j] >> 8) & 0xff);
6298                                                         data [p++] = (byte) ((nbits [j] >> 16) & 0xff);
6299                                                         data [p++] = (byte) (nbits [j] >> 24);
6300                                                 }
6301                                         }
6302                                 } else
6303                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
6304
6305                                 idx += factor;
6306                         }
6307
6308                         return data;
6309                 }
6310
6311                 //
6312                 // Emits the initializers for the array
6313                 //
6314                 void EmitStaticInitializers (EmitContext ec)
6315                 {
6316                         //
6317                         // First, the static data
6318                         //
6319                         FieldBuilder fb;
6320                         ILGenerator ig = ec.ig;
6321
6322                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
6323
6324                         fb = RootContext.MakeStaticData (data);
6325
6326                         ig.Emit (OpCodes.Dup);
6327                         ig.Emit (OpCodes.Ldtoken, fb);
6328                         ig.Emit (OpCodes.Call,
6329                                  TypeManager.void_initializearray_array_fieldhandle);
6330                 }
6331
6332                 //
6333                 // Emits pieces of the array that can not be computed at compile
6334                 // time (variables and string locations).
6335                 //
6336                 // This always expect the top value on the stack to be the array
6337                 //
6338                 void EmitDynamicInitializers (EmitContext ec)
6339                 {
6340                         ILGenerator ig = ec.ig;
6341                         int dims = bounds.Count;
6342                         int [] current_pos = new int [dims];
6343                         int top = array_data.Count;
6344
6345                         MethodInfo set = null;
6346
6347                         if (dims != 1){
6348                                 Type [] args;
6349                                 ModuleBuilder mb = null;
6350                                 mb = CodeGen.Module.Builder;
6351                                 args = new Type [dims + 1];
6352
6353                                 int j;
6354                                 for (j = 0; j < dims; j++)
6355                                         args [j] = TypeManager.int32_type;
6356
6357                                 args [j] = array_element_type;
6358
6359                                 set = mb.GetArrayMethod (
6360                                         type, "Set",
6361                                         CallingConventions.HasThis | CallingConventions.Standard,
6362                                         TypeManager.void_type, args);
6363                         }
6364
6365                         for (int i = 0; i < top; i++){
6366
6367                                 Expression e = null;
6368
6369                                 if (array_data [i] is Expression)
6370                                         e = (Expression) array_data [i];
6371
6372                                 if (e != null) {
6373                                         //
6374                                         // Basically we do this for string literals and
6375                                         // other non-literal expressions
6376                                         //
6377                                         if (e is EnumConstant){
6378                                                 e = ((EnumConstant) e).Child;
6379                                         }
6380
6381                                         if (e is StringConstant || e is DecimalConstant || !(e is Constant) ||
6382                                             num_automatic_initializers <= max_automatic_initializers) {
6383                                                 Type etype = e.Type;
6384
6385                                                 ig.Emit (OpCodes.Dup);
6386
6387                                                 for (int idx = 0; idx < dims; idx++)
6388                                                         IntConstant.EmitInt (ig, current_pos [idx]);
6389
6390                                                 //
6391                                                 // If we are dealing with a struct, get the
6392                                                 // address of it, so we can store it.
6393                                                 //
6394                                                 if ((dims == 1) &&
6395                                                     etype.IsSubclassOf (TypeManager.value_type) &&
6396                                                     (!TypeManager.IsBuiltinOrEnum (etype) ||
6397                                                      etype == TypeManager.decimal_type)) {
6398                                                         if (e is New){
6399                                                                 New n = (New) e;
6400
6401                                                                 //
6402                                                                 // Let new know that we are providing
6403                                                                 // the address where to store the results
6404                                                                 //
6405                                                                 n.DisableTemporaryValueType ();
6406                                                         }
6407
6408                                                         ig.Emit (OpCodes.Ldelema, etype);
6409                                                 }
6410
6411                                                 e.Emit (ec);
6412
6413                                                 if (dims == 1) {
6414                                                         bool is_stobj;
6415                                                         OpCode op = ArrayAccess.GetStoreOpcode (etype, out is_stobj);
6416                                                         if (is_stobj)
6417                                                                 ig.Emit (OpCodes.Stobj, etype);
6418                                                         else
6419                                                                 ig.Emit (op);
6420                                                 } else
6421                                                         ig.Emit (OpCodes.Call, set);
6422
6423                                         }
6424                                 }
6425
6426                                 //
6427                                 // Advance counter
6428                                 //
6429                                 for (int j = dims - 1; j >= 0; j--){
6430                                         current_pos [j]++;
6431                                         if (current_pos [j] < (int) bounds [j])
6432                                                 break;
6433                                         current_pos [j] = 0;
6434                                 }
6435                         }
6436                 }
6437
6438                 void EmitArrayArguments (EmitContext ec)
6439                 {
6440                         ILGenerator ig = ec.ig;
6441
6442                         foreach (Argument a in arguments) {
6443                                 Type atype = a.Type;
6444                                 a.Emit (ec);
6445
6446                                 if (atype == TypeManager.uint64_type)
6447                                         ig.Emit (OpCodes.Conv_Ovf_U4);
6448                                 else if (atype == TypeManager.int64_type)
6449                                         ig.Emit (OpCodes.Conv_Ovf_I4);
6450                         }
6451                 }
6452
6453                 public override void Emit (EmitContext ec)
6454                 {
6455                         ILGenerator ig = ec.ig;
6456
6457                         EmitArrayArguments (ec);
6458                         if (is_one_dimensional)
6459                                 ig.Emit (OpCodes.Newarr, array_element_type);
6460                         else {
6461                                 if (is_builtin_type)
6462                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
6463                                 else
6464                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
6465                         }
6466
6467                         if (initializers != null){
6468                                 //
6469                                 // FIXME: Set this variable correctly.
6470                                 //
6471                                 bool dynamic_initializers = true;
6472
6473                                 // This will never be true for array types that cannot be statically
6474                                 // initialized. num_automatic_initializers will always be zero.  See
6475                                 // CheckIndices.
6476                                 if (num_automatic_initializers > max_automatic_initializers)
6477                                         EmitStaticInitializers (ec);
6478
6479                                 if (dynamic_initializers)
6480                                         EmitDynamicInitializers (ec);
6481                         }
6482                 }
6483
6484                 public object EncodeAsAttribute ()
6485                 {
6486                         if (!is_one_dimensional){
6487                                 Report.Error (-211, Location, "attribute can not encode multi-dimensional arrays");
6488                                 return null;
6489                         }
6490
6491                         if (array_data == null){
6492                                 Report.Error (-212, Location, "array should be initialized when passing it to an attribute");
6493                                 return null;
6494                         }
6495
6496                         object [] ret = new object [array_data.Count];
6497                         int i = 0;
6498                         foreach (Expression e in array_data){
6499                                 object v;
6500
6501                                 if (e is NullLiteral)
6502                                         v = null;
6503                                 else {
6504                                         if (!Attribute.GetAttributeArgumentExpression (e, Location, array_element_type, out v))
6505                                                 return null;
6506                                 }
6507                                 ret [i++] = v;
6508                         }
6509                         return ret;
6510                 }
6511         }
6512
6513         /// <summary>
6514         ///   Represents the `this' construct
6515         /// </summary>
6516         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
6517
6518                 Block block;
6519                 VariableInfo variable_info;
6520
6521                 public This (Block block, Location loc)
6522                 {
6523                         this.loc = loc;
6524                         this.block = block;
6525                 }
6526
6527                 public This (Location loc)
6528                 {
6529                         this.loc = loc;
6530                 }
6531
6532                 public VariableInfo VariableInfo {
6533                         get { return variable_info; }
6534                 }
6535
6536                 public bool VerifyFixed (bool is_expression)
6537                 {
6538                         if ((variable_info == null) || (variable_info.LocalInfo == null))
6539                                 return false;
6540                         else
6541                                 return variable_info.LocalInfo.IsFixed;
6542                 }
6543
6544                 public bool ResolveBase (EmitContext ec)
6545                 {
6546                         eclass = ExprClass.Variable;
6547                         type = ec.ContainerType;
6548
6549                         if (ec.IsStatic) {
6550                                 Error (26, "Keyword this not valid in static code");
6551                                 return false;
6552                         }
6553
6554                         if ((block != null) && (block.ThisVariable != null))
6555                                 variable_info = block.ThisVariable.VariableInfo;
6556
6557                         return true;
6558                 }
6559
6560                 public override Expression DoResolve (EmitContext ec)
6561                 {
6562                         if (!ResolveBase (ec))
6563                                 return null;
6564
6565                         if ((variable_info != null) && !variable_info.IsAssigned (ec)) {
6566                                 Error (188, "The this object cannot be used before all " +
6567                                        "of its fields are assigned to");
6568                                 variable_info.SetAssigned (ec);
6569                                 return this;
6570                         }
6571
6572                         if (ec.IsFieldInitializer) {
6573                                 Error (27, "Keyword `this' can't be used outside a constructor, " +
6574                                        "a method or a property.");
6575                                 return null;
6576                         }
6577
6578                         return this;
6579                 }
6580
6581                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
6582                 {
6583                         if (!ResolveBase (ec))
6584                                 return null;
6585
6586                         if (variable_info != null)
6587                                 variable_info.SetAssigned (ec);
6588
6589                         if (ec.TypeContainer is Class){
6590                                 Error (1604, "Cannot assign to `this'");
6591                                 return null;
6592                         }
6593
6594                         return this;
6595                 }
6596
6597                 public void Emit (EmitContext ec, bool leave_copy)
6598                 {
6599                         Emit (ec);
6600                         if (leave_copy)
6601                                 ec.ig.Emit (OpCodes.Dup);
6602                 }
6603
6604                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
6605                 {
6606                         ILGenerator ig = ec.ig;
6607
6608                         if (ec.TypeContainer is Struct){
6609                                 ec.EmitThis ();
6610                                 source.Emit (ec);
6611                                 if (leave_copy)
6612                                         ec.ig.Emit (OpCodes.Dup);
6613                                 ig.Emit (OpCodes.Stobj, type);
6614                         } else {
6615                                 throw new Exception ("how did you get here");
6616                         }
6617                 }
6618
6619                 public override void Emit (EmitContext ec)
6620                 {
6621                         ILGenerator ig = ec.ig;
6622
6623                         ec.EmitThis ();
6624                         if (ec.TypeContainer is Struct)
6625                                 ig.Emit (OpCodes.Ldobj, type);
6626                 }
6627
6628                 public void AddressOf (EmitContext ec, AddressOp mode)
6629                 {
6630                         ec.EmitThis ();
6631
6632                         // FIMXE
6633                         // FIGURE OUT WHY LDARG_S does not work
6634                         //
6635                         // consider: struct X { int val; int P { set { val = value; }}}
6636                         //
6637                         // Yes, this looks very bad. Look at `NOTAS' for
6638                         // an explanation.
6639                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
6640                 }
6641         }
6642
6643         /// <summary>
6644         ///   Represents the `__arglist' construct
6645         /// </summary>
6646         public class ArglistAccess : Expression
6647         {
6648                 public ArglistAccess (Location loc)
6649                 {
6650                         this.loc = loc;
6651                 }
6652
6653                 public bool ResolveBase (EmitContext ec)
6654                 {
6655                         eclass = ExprClass.Variable;
6656                         type = TypeManager.runtime_argument_handle_type;
6657                         return true;
6658                 }
6659
6660                 public override Expression DoResolve (EmitContext ec)
6661                 {
6662                         if (!ResolveBase (ec))
6663                                 return null;
6664
6665                         if (ec.IsFieldInitializer || !ec.CurrentBlock.HasVarargs) {
6666                                 Error (190, "The __arglist construct is valid only within " +
6667                                        "a variable argument method.");
6668                                 return null;
6669                         }
6670
6671                         return this;
6672                 }
6673
6674                 public override void Emit (EmitContext ec)
6675                 {
6676                         ec.ig.Emit (OpCodes.Arglist);
6677                 }
6678         }
6679
6680         /// <summary>
6681         ///   Represents the `__arglist (....)' construct
6682         /// </summary>
6683         public class Arglist : Expression
6684         {
6685                 public readonly Argument[] Arguments;
6686
6687                 public Arglist (Argument[] args, Location l)
6688                 {
6689                         Arguments = args;
6690                         loc = l;
6691                 }
6692
6693                 public Type[] ArgumentTypes {
6694                         get {
6695                                 Type[] retval = new Type [Arguments.Length];
6696                                 for (int i = 0; i < Arguments.Length; i++)
6697                                         retval [i] = Arguments [i].Type;
6698                                 return retval;
6699                         }
6700                 }
6701
6702                 public override Expression DoResolve (EmitContext ec)
6703                 {
6704                         eclass = ExprClass.Variable;
6705                         type = TypeManager.runtime_argument_handle_type;
6706
6707                         foreach (Argument arg in Arguments) {
6708                                 if (!arg.Resolve (ec, loc))
6709                                         return null;
6710                         }
6711
6712                         return this;
6713                 }
6714
6715                 public override void Emit (EmitContext ec)
6716                 {
6717                         foreach (Argument arg in Arguments)
6718                                 arg.Emit (ec);
6719                 }
6720         }
6721
6722         //
6723         // This produces the value that renders an instance, used by the iterators code
6724         //
6725         public class ProxyInstance : Expression, IMemoryLocation  {
6726                 public override Expression DoResolve (EmitContext ec)
6727                 {
6728                         eclass = ExprClass.Variable;
6729                         type = ec.ContainerType;
6730                         return this;
6731                 }
6732
6733                 public override void Emit (EmitContext ec)
6734                 {
6735                         ec.ig.Emit (OpCodes.Ldarg_0);
6736
6737                 }
6738
6739                 public void AddressOf (EmitContext ec, AddressOp mode)
6740                 {
6741                         ec.ig.Emit (OpCodes.Ldarg_0);
6742                 }
6743         }
6744
6745         /// <summary>
6746         ///   Implements the typeof operator
6747         /// </summary>
6748         public class TypeOf : Expression {
6749                 public readonly Expression QueriedType;
6750                 protected Type typearg;
6751
6752                 public TypeOf (Expression queried_type, Location l)
6753                 {
6754                         QueriedType = queried_type;
6755                         loc = l;
6756                 }
6757
6758                 public override Expression DoResolve (EmitContext ec)
6759                 {
6760                         typearg = ec.DeclSpace.ResolveType (QueriedType, false, loc);
6761
6762                         if (typearg == null)
6763                                 return null;
6764
6765                         if (typearg == TypeManager.void_type) {
6766                                 Error (673, "System.Void cannot be used from C# - " +
6767                                        "use typeof (void) to get the void type object");
6768                                 return null;
6769                         }
6770
6771                         if (typearg.IsPointer && !ec.InUnsafe){
6772                                 UnsafeError (loc);
6773                                 return null;
6774                         }
6775                         CheckObsoleteAttribute (typearg);
6776
6777                         type = TypeManager.type_type;
6778                         eclass = ExprClass.Type;
6779                         return this;
6780                 }
6781
6782                 public override void Emit (EmitContext ec)
6783                 {
6784                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
6785                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
6786                 }
6787
6788                 public Type TypeArg {
6789                         get { return typearg; }
6790                 }
6791         }
6792
6793         /// <summary>
6794         ///   Implements the `typeof (void)' operator
6795         /// </summary>
6796         public class TypeOfVoid : TypeOf {
6797                 public TypeOfVoid (Location l) : base (null, l)
6798                 {
6799                         loc = l;
6800                 }
6801
6802                 public override Expression DoResolve (EmitContext ec)
6803                 {
6804                         type = TypeManager.type_type;
6805                         typearg = TypeManager.void_type;
6806                         eclass = ExprClass.Type;
6807                         return this;
6808                 }
6809         }
6810
6811         /// <summary>
6812         ///   Implements the sizeof expression
6813         /// </summary>
6814         public class SizeOf : Expression {
6815                 public readonly Expression QueriedType;
6816                 Type type_queried;
6817
6818                 public SizeOf (Expression queried_type, Location l)
6819                 {
6820                         this.QueriedType = queried_type;
6821                         loc = l;
6822                 }
6823
6824                 public override Expression DoResolve (EmitContext ec)
6825                 {
6826                         if (!ec.InUnsafe) {
6827                                 Report.Error (
6828                                         233, loc, "Sizeof may only be used in an unsafe context " +
6829                                         "(consider using System.Runtime.InteropServices.Marshal.Sizeof");
6830                                 return null;
6831                         }
6832
6833                         type_queried = ec.DeclSpace.ResolveType (QueriedType, false, loc);
6834                         if (type_queried == null)
6835                                 return null;
6836
6837                         CheckObsoleteAttribute (type_queried);
6838
6839                         if (!TypeManager.IsUnmanagedType (type_queried)){
6840                                 Report.Error (208, loc, "Cannot take the size of an unmanaged type (" + TypeManager.CSharpName (type_queried) + ")");
6841                                 return null;
6842                         }
6843
6844                         type = TypeManager.int32_type;
6845                         eclass = ExprClass.Value;
6846                         return this;
6847                 }
6848
6849                 public override void Emit (EmitContext ec)
6850                 {
6851                         int size = GetTypeSize (type_queried);
6852
6853                         if (size == 0)
6854                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
6855                         else
6856                                 IntConstant.EmitInt (ec.ig, size);
6857                 }
6858         }
6859
6860         /// <summary>
6861         ///   Implements the member access expression
6862         /// </summary>
6863         public class MemberAccess : Expression {
6864                 public readonly string Identifier;
6865                 Expression expr;
6866
6867                 public MemberAccess (Expression expr, string id, Location l)
6868                 {
6869                         this.expr = expr;
6870                         Identifier = id;
6871                         loc = l;
6872                 }
6873
6874                 public Expression Expr {
6875                         get {
6876                                 return expr;
6877                         }
6878                 }
6879
6880                 public static void error176 (Location loc, string name)
6881                 {
6882                         Report.Error (176, loc, "Static member `" +
6883                                       name + "' cannot be accessed " +
6884                                       "with an instance reference, qualify with a " +
6885                                       "type name instead");
6886                 }
6887
6888                 public static bool IdenticalNameAndTypeName (EmitContext ec, Expression left_original, Expression left, Location loc)
6889                 {
6890                         SimpleName sn = left_original as SimpleName;
6891                         if (sn == null || left == null || left.Type.Name != sn.Name)
6892                                 return false;
6893
6894                         return RootContext.LookupType (ec.DeclSpace, sn.Name, true, loc) != null;
6895                 }
6896
6897                 public static Expression ResolveMemberAccess (EmitContext ec, Expression member_lookup,
6898                                                               Expression left, Location loc,
6899                                                               Expression left_original)
6900                 {
6901                         bool left_is_type, left_is_explicit;
6902
6903                         // If `left' is null, then we're called from SimpleNameResolve and this is
6904                         // a member in the currently defining class.
6905                         if (left == null) {
6906                                 left_is_type = ec.IsStatic || ec.IsFieldInitializer;
6907                                 left_is_explicit = false;
6908
6909                                 // Implicitly default to `this' unless we're static.
6910                                 if (!ec.IsStatic && !ec.IsFieldInitializer && !ec.InEnumContext)
6911                                         left = ec.GetThis (loc);
6912                         } else {
6913                                 left_is_type = left is TypeExpr;
6914                                 left_is_explicit = true;
6915                         }
6916
6917                         if (member_lookup is FieldExpr){
6918                                 FieldExpr fe = (FieldExpr) member_lookup;
6919                                 FieldInfo fi = fe.FieldInfo;
6920                                 Type decl_type = fi.DeclaringType;
6921
6922                                 if (fi is FieldBuilder) {
6923                                         Const c = TypeManager.LookupConstant ((FieldBuilder) fi);
6924
6925                                         if (c != null) {
6926                                                 object o;
6927                                                 if (!c.LookupConstantValue (out o))
6928                                                         return null;
6929
6930                                                 object real_value = ((Constant) c.Expr).GetValue ();
6931
6932                                                 return Constantify (real_value, fi.FieldType);
6933                                         }
6934                                 }
6935
6936                                 if (fi.IsLiteral) {
6937                                         Type t = fi.FieldType;
6938
6939                                         object o;
6940
6941                                         if (fi is FieldBuilder)
6942                                                 o = TypeManager.GetValue ((FieldBuilder) fi);
6943                                         else
6944                                                 o = fi.GetValue (fi);
6945
6946                                         if (decl_type.IsSubclassOf (TypeManager.enum_type)) {
6947                                                 if (left_is_explicit && !left_is_type &&
6948                                                     !IdenticalNameAndTypeName (ec, left_original, member_lookup, loc)) {
6949                                                         error176 (loc, fe.FieldInfo.Name);
6950                                                         return null;
6951                                                 }
6952
6953                                                 Expression enum_member = MemberLookup (
6954                                                         ec, decl_type, "value__", MemberTypes.Field,
6955                                                         AllBindingFlags, loc);
6956
6957                                                 Enum en = TypeManager.LookupEnum (decl_type);
6958
6959                                                 Constant c;
6960                                                 if (en != null)
6961                                                         c = Constantify (o, en.UnderlyingType);
6962                                                 else
6963                                                         c = Constantify (o, enum_member.Type);
6964
6965                                                 return new EnumConstant (c, decl_type);
6966                                         }
6967
6968                                         Expression exp = Constantify (o, t);
6969
6970                                         if (left_is_explicit && !left_is_type) {
6971                                                 error176 (loc, fe.FieldInfo.Name);
6972                                                 return null;
6973                                         }
6974
6975                                         return exp;
6976                                 }
6977
6978                                 if (fi.FieldType.IsPointer && !ec.InUnsafe){
6979                                         UnsafeError (loc);
6980                                         return null;
6981                                 }
6982                         }
6983
6984                         if (member_lookup is EventExpr) {
6985                                 EventExpr ee = (EventExpr) member_lookup;
6986
6987                                 //
6988                                 // If the event is local to this class, we transform ourselves into
6989                                 // a FieldExpr
6990                                 //
6991
6992                                 if (ee.EventInfo.DeclaringType == ec.ContainerType ||
6993                                     TypeManager.IsNestedChildOf(ec.ContainerType, ee.EventInfo.DeclaringType)) {
6994                                         MemberInfo mi = GetFieldFromEvent (ee);
6995
6996                                         if (mi == null) {
6997                                                 //
6998                                                 // If this happens, then we have an event with its own
6999                                                 // accessors and private field etc so there's no need
7000                                                 // to transform ourselves.
7001                                                 //
7002                                                 ee.InstanceExpression = left;
7003                                                 return ee;
7004                                         }
7005
7006                                         Expression ml = ExprClassFromMemberInfo (ec, mi, loc);
7007
7008                                         if (ml == null) {
7009                                                 Report.Error (-200, loc, "Internal error!!");
7010                                                 return null;
7011                                         }
7012
7013                                         if (!left_is_explicit)
7014                                                 left = null;
7015
7016                                         ee.InstanceExpression = left;
7017
7018                                         return ResolveMemberAccess (ec, ml, left, loc, left_original);
7019                                 }
7020                         }
7021
7022                         if (member_lookup is IMemberExpr) {
7023                                 IMemberExpr me = (IMemberExpr) member_lookup;
7024                                 MethodGroupExpr mg = me as MethodGroupExpr;
7025
7026                                 if (left_is_type){
7027                                         if ((mg != null) && left_is_explicit && left.Type.IsInterface)
7028                                                 mg.IsExplicitImpl = left_is_explicit;
7029
7030                                         if (!me.IsStatic){
7031                                                 if ((ec.IsFieldInitializer || ec.IsStatic) &&
7032                                                     IdenticalNameAndTypeName (ec, left_original, member_lookup, loc))
7033                                                         return member_lookup;
7034
7035                                                 SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
7036                                                 return null;
7037                                         }
7038
7039                                 } else {
7040                                         if (!me.IsInstance) {
7041                                                 if (IdenticalNameAndTypeName (ec, left_original, left, loc))
7042                                                         return member_lookup;
7043
7044                                                 if (left_is_explicit) {
7045                                                         error176 (loc, me.Name);
7046                                                         return null;
7047                                                 }
7048                                         }
7049
7050                                         //
7051                                         // Since we can not check for instance objects in SimpleName,
7052                                         // becaue of the rule that allows types and variables to share
7053                                         // the name (as long as they can be de-ambiguated later, see
7054                                         // IdenticalNameAndTypeName), we have to check whether left
7055                                         // is an instance variable in a static context
7056                                         //
7057                                         // However, if the left-hand value is explicitly given, then
7058                                         // it is already our instance expression, so we aren't in
7059                                         // static context.
7060                                         //
7061
7062                                         if (ec.IsStatic && !left_is_explicit && left is IMemberExpr){
7063                                                 IMemberExpr mexp = (IMemberExpr) left;
7064
7065                                                 if (!mexp.IsStatic){
7066                                                         SimpleName.Error_ObjectRefRequired (ec, loc, mexp.Name);
7067                                                         return null;
7068                                                 }
7069                                         }
7070
7071                                         if ((mg != null) && IdenticalNameAndTypeName (ec, left_original, left, loc))
7072                                                 mg.IdenticalTypeName = true;
7073
7074                                         me.InstanceExpression = left;
7075                                 }
7076
7077                                 return member_lookup;
7078                         }
7079
7080                         Console.WriteLine ("Left is: " + left);
7081                         Report.Error (-100, loc, "Support for [" + member_lookup + "] is not present yet");
7082                         Environment.Exit (1);
7083                         return null;
7084                 }
7085
7086                 public Expression DoResolve (EmitContext ec, Expression right_side, ResolveFlags flags)
7087                 {
7088                         if (type != null)
7089                                 throw new Exception ();
7090
7091                         //
7092                         // Resolve the expression with flow analysis turned off, we'll do the definite
7093                         // assignment checks later.  This is because we don't know yet what the expression
7094                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
7095                         // definite assignment check on the actual field and not on the whole struct.
7096                         //
7097
7098                         Expression original = expr;
7099                         expr = expr.Resolve (ec, flags | ResolveFlags.Intermediate | ResolveFlags.DisableFlowAnalysis);
7100                         if (expr == null)
7101                                 return null;
7102
7103                         if (expr is SimpleName){
7104                                 SimpleName child_expr = (SimpleName) expr;
7105
7106                                 Expression new_expr = new SimpleName (child_expr.Name, Identifier, loc);
7107
7108                                 return new_expr.Resolve (ec, flags);
7109                         }
7110
7111                         //
7112                         // TODO: I mailed Ravi about this, and apparently we can get rid
7113                         // of this and put it in the right place.
7114                         //
7115                         // Handle enums here when they are in transit.
7116                         // Note that we cannot afford to hit MemberLookup in this case because
7117                         // it will fail to find any members at all
7118                         //
7119
7120                         Type expr_type = expr.Type;
7121                         if (expr is TypeExpr){
7122                                 if (!ec.DeclSpace.CheckAccessLevel (expr_type)){
7123                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", expr_type);
7124                                         return null;
7125                                 }
7126
7127                                 if (expr_type == TypeManager.enum_type || expr_type.IsSubclassOf (TypeManager.enum_type)){
7128                                         Enum en = TypeManager.LookupEnum (expr_type);
7129
7130                                         if (en != null) {
7131                                                 object value = en.LookupEnumValue (ec, Identifier, loc);
7132
7133                                                 if (value != null){
7134                                                         MemberCore mc = en.GetDefinition (Identifier);
7135                                                         ObsoleteAttribute oa = mc.GetObsoleteAttribute (en);
7136                                                         if (oa != null) {
7137                                                                 AttributeTester.Report_ObsoleteMessage (oa, mc.GetSignatureForError (), Location);
7138                                                         }
7139                                                         oa = en.GetObsoleteAttribute (en);
7140                                                         if (oa != null) {
7141                                                                 AttributeTester.Report_ObsoleteMessage (oa, en.GetSignatureForError (), Location);
7142                                                         }
7143
7144                                                         Constant c = Constantify (value, en.UnderlyingType);
7145                                                         return new EnumConstant (c, expr_type);
7146                                                 }
7147                                         } else {
7148                                                 CheckObsoleteAttribute (expr_type);
7149
7150                                                 FieldInfo fi = expr_type.GetField (Identifier);
7151                                                 if (fi != null) {
7152                                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (fi);
7153                                                         if (oa != null)
7154                                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (fi), Location);
7155                                                 }
7156                                         }
7157                                 }
7158                         }
7159
7160                         if (expr_type.IsPointer){
7161                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7162                                        TypeManager.CSharpName (expr_type) + ")");
7163                                 return null;
7164                         }
7165
7166                         Expression member_lookup;
7167                         member_lookup = MemberLookupFinal (ec, expr_type, expr_type, Identifier, loc);
7168                         if (member_lookup == null)
7169                                 return null;
7170
7171                         if (member_lookup is TypeExpr) {
7172                                 if (!(expr is TypeExpr) && !(expr is SimpleName)) {
7173                                         Error (572, "Can't reference type `" + Identifier + "' through an expression; try `" +
7174                                                member_lookup.Type + "' instead");
7175                                         return null;
7176                                 }
7177
7178                                 return member_lookup;
7179                         }
7180
7181                         member_lookup = ResolveMemberAccess (ec, member_lookup, expr, loc, original);
7182                         if (member_lookup == null)
7183                                 return null;
7184
7185                         // The following DoResolve/DoResolveLValue will do the definite assignment
7186                         // check.
7187
7188                         if (right_side != null)
7189                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
7190                         else
7191                                 member_lookup = member_lookup.DoResolve (ec);
7192
7193                         return member_lookup;
7194                 }
7195
7196                 public override Expression DoResolve (EmitContext ec)
7197                 {
7198                         return DoResolve (ec, null, ResolveFlags.VariableOrValue |
7199                                           ResolveFlags.SimpleName | ResolveFlags.Type);
7200                 }
7201
7202                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7203                 {
7204                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue |
7205                                           ResolveFlags.SimpleName | ResolveFlags.Type);
7206                 }
7207
7208                 public override Expression ResolveAsTypeStep (EmitContext ec)
7209                 {
7210                         string fname = null;
7211                         MemberAccess full_expr = this;
7212                         while (full_expr != null) {
7213                                 if (fname != null)
7214                                         fname = String.Concat (full_expr.Identifier, ".", fname);
7215                                 else
7216                                         fname = full_expr.Identifier;
7217
7218                                 if (full_expr.Expr is SimpleName) {
7219                                         string full_name = String.Concat (((SimpleName) full_expr.Expr).Name, ".", fname);
7220                                         Type fully_qualified = ec.DeclSpace.FindType (loc, full_name);
7221                                         if (fully_qualified != null)
7222                                                 return new TypeExpression (fully_qualified, loc);
7223                                 }
7224
7225                                 full_expr = full_expr.Expr as MemberAccess;
7226                         }
7227
7228                         Expression new_expr = expr.ResolveAsTypeStep (ec);
7229
7230                         if (new_expr == null)
7231                                 return null;
7232
7233                         if (new_expr is SimpleName){
7234                                 SimpleName child_expr = (SimpleName) new_expr;
7235
7236                                 new_expr = new SimpleName (child_expr.Name, Identifier, loc);
7237
7238                                 return new_expr.ResolveAsTypeStep (ec);
7239                         }
7240
7241                         Type expr_type = new_expr.Type;
7242
7243                         if (expr_type.IsPointer){
7244                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
7245                                        TypeManager.CSharpName (expr_type) + ")");
7246                                 return null;
7247                         }
7248
7249                         Expression member_lookup;
7250                         member_lookup = MemberLookupFinal (ec, expr_type, expr_type, Identifier, loc);
7251                         if (member_lookup == null)
7252                                 return null;
7253
7254                         if (member_lookup is TypeExpr){
7255                                 member_lookup.Resolve (ec, ResolveFlags.Type);
7256                                 return member_lookup;
7257                         }
7258
7259                         return null;
7260                 }
7261
7262                 public override void Emit (EmitContext ec)
7263                 {
7264                         throw new Exception ("Should not happen");
7265                 }
7266
7267                 public override string ToString ()
7268                 {
7269                         return expr + "." + Identifier;
7270                 }
7271         }
7272
7273         /// <summary>
7274         ///   Implements checked expressions
7275         /// </summary>
7276         public class CheckedExpr : Expression {
7277
7278                 public Expression Expr;
7279
7280                 public CheckedExpr (Expression e, Location l)
7281                 {
7282                         Expr = e;
7283                         loc = l;
7284                 }
7285
7286                 public override Expression DoResolve (EmitContext ec)
7287                 {
7288                         bool last_check = ec.CheckState;
7289                         bool last_const_check = ec.ConstantCheckState;
7290
7291                         ec.CheckState = true;
7292                         ec.ConstantCheckState = true;
7293                         Expr = Expr.Resolve (ec);
7294                         ec.CheckState = last_check;
7295                         ec.ConstantCheckState = last_const_check;
7296
7297                         if (Expr == null)
7298                                 return null;
7299
7300                         if (Expr is Constant)
7301                                 return Expr;
7302
7303                         eclass = Expr.eclass;
7304                         type = Expr.Type;
7305                         return this;
7306                 }
7307
7308                 public override void Emit (EmitContext ec)
7309                 {
7310                         bool last_check = ec.CheckState;
7311                         bool last_const_check = ec.ConstantCheckState;
7312
7313                         ec.CheckState = true;
7314                         ec.ConstantCheckState = true;
7315                         Expr.Emit (ec);
7316                         ec.CheckState = last_check;
7317                         ec.ConstantCheckState = last_const_check;
7318                 }
7319
7320         }
7321
7322         /// <summary>
7323         ///   Implements the unchecked expression
7324         /// </summary>
7325         public class UnCheckedExpr : Expression {
7326
7327                 public Expression Expr;
7328
7329                 public UnCheckedExpr (Expression e, Location l)
7330                 {
7331                         Expr = e;
7332                         loc = l;
7333                 }
7334
7335                 public override Expression DoResolve (EmitContext ec)
7336                 {
7337                         bool last_check = ec.CheckState;
7338                         bool last_const_check = ec.ConstantCheckState;
7339
7340                         ec.CheckState = false;
7341                         ec.ConstantCheckState = false;
7342                         Expr = Expr.Resolve (ec);
7343                         ec.CheckState = last_check;
7344                         ec.ConstantCheckState = last_const_check;
7345
7346                         if (Expr == null)
7347                                 return null;
7348
7349                         if (Expr is Constant)
7350                                 return Expr;
7351
7352                         eclass = Expr.eclass;
7353                         type = Expr.Type;
7354                         return this;
7355                 }
7356
7357                 public override void Emit (EmitContext ec)
7358                 {
7359                         bool last_check = ec.CheckState;
7360                         bool last_const_check = ec.ConstantCheckState;
7361
7362                         ec.CheckState = false;
7363                         ec.ConstantCheckState = false;
7364                         Expr.Emit (ec);
7365                         ec.CheckState = last_check;
7366                         ec.ConstantCheckState = last_const_check;
7367                 }
7368
7369         }
7370
7371         /// <summary>
7372         ///   An Element Access expression.
7373         ///
7374         ///   During semantic analysis these are transformed into
7375         ///   IndexerAccess, ArrayAccess or a PointerArithmetic.
7376         /// </summary>
7377         public class ElementAccess : Expression {
7378                 public ArrayList  Arguments;
7379                 public Expression Expr;
7380
7381                 public ElementAccess (Expression e, ArrayList e_list, Location l)
7382                 {
7383                         Expr = e;
7384
7385                         loc  = l;
7386
7387                         if (e_list == null)
7388                                 return;
7389
7390                         Arguments = new ArrayList ();
7391                         foreach (Expression tmp in e_list)
7392                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
7393
7394                 }
7395
7396                 bool CommonResolve (EmitContext ec)
7397                 {
7398                         Expr = Expr.Resolve (ec);
7399
7400                         if (Expr == null)
7401                                 return false;
7402
7403                         if (Arguments == null)
7404                                 return false;
7405
7406                         foreach (Argument a in Arguments){
7407                                 if (!a.Resolve (ec, loc))
7408                                         return false;
7409                         }
7410
7411                         return true;
7412                 }
7413
7414                 Expression MakePointerAccess (EmitContext ec)
7415                 {
7416                         Type t = Expr.Type;
7417
7418                         if (t == TypeManager.void_ptr_type){
7419                                 Error (242, "The array index operation is not valid for void pointers");
7420                                 return null;
7421                         }
7422                         if (Arguments.Count != 1){
7423                                 Error (196, "A pointer must be indexed by a single value");
7424                                 return null;
7425                         }
7426                         Expression p;
7427
7428                         p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr, t, loc).Resolve (ec);
7429                         if (p == null)
7430                                 return null;
7431                         return new Indirection (p, loc).Resolve (ec);
7432                 }
7433
7434                 public override Expression DoResolve (EmitContext ec)
7435                 {
7436                         if (!CommonResolve (ec))
7437                                 return null;
7438
7439                         //
7440                         // We perform some simple tests, and then to "split" the emit and store
7441                         // code we create an instance of a different class, and return that.
7442                         //
7443                         // I am experimenting with this pattern.
7444                         //
7445                         Type t = Expr.Type;
7446
7447                         if (t == TypeManager.array_type){
7448                                 Report.Error (21, loc, "Cannot use indexer on System.Array");
7449                                 return null;
7450                         }
7451
7452                         if (t.IsArray)
7453                                 return (new ArrayAccess (this, loc)).Resolve (ec);
7454                         else if (t.IsPointer)
7455                                 return MakePointerAccess (ec);
7456                         else
7457                                 return (new IndexerAccess (this, loc)).Resolve (ec);
7458                 }
7459
7460                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
7461                 {
7462                         if (!CommonResolve (ec))
7463                                 return null;
7464
7465                         Type t = Expr.Type;
7466                         if (t.IsArray)
7467                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
7468                         else if (t.IsPointer)
7469                                 return MakePointerAccess (ec);
7470                         else
7471                                 return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
7472                 }
7473
7474                 public override void Emit (EmitContext ec)
7475                 {
7476                         throw new Exception ("Should never be reached");
7477                 }
7478         }
7479
7480         /// <summary>
7481         ///   Implements array access
7482         /// </summary>
7483         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
7484                 //
7485                 // Points to our "data" repository
7486                 //
7487                 ElementAccess ea;
7488
7489                 LocalTemporary temp;
7490                 bool prepared;
7491
7492                 public ArrayAccess (ElementAccess ea_data, Location l)
7493                 {
7494                         ea = ea_data;
7495                         eclass = ExprClass.Variable;
7496                         loc = l;
7497                 }
7498
7499                 public override Expression DoResolve (EmitContext ec)
7500                 {
7501 #if false
7502                         ExprClass eclass = ea.Expr.eclass;
7503
7504                         // As long as the type is valid
7505                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
7506                               eclass == ExprClass.Value)) {
7507                                 ea.Expr.Error_UnexpectedKind ("variable or value");
7508                                 return null;
7509                         }
7510 #endif
7511
7512                         Type t = ea.Expr.Type;
7513                         if (t.GetArrayRank () != ea.Arguments.Count){
7514                                 ea.Error (22,
7515                                           "Incorrect number of indexes for array " +
7516                                           " expected: " + t.GetArrayRank () + " got: " +
7517                                           ea.Arguments.Count);
7518                                 return null;
7519                         }
7520
7521                         type = TypeManager.GetElementType (t);
7522                         if (type.IsPointer && !ec.InUnsafe){
7523                                 UnsafeError (ea.Location);
7524                                 return null;
7525                         }
7526
7527                         foreach (Argument a in ea.Arguments){
7528                                 Type argtype = a.Type;
7529
7530                                 if (argtype == TypeManager.int32_type ||
7531                                     argtype == TypeManager.uint32_type ||
7532                                     argtype == TypeManager.int64_type ||
7533                                     argtype == TypeManager.uint64_type)
7534                                         continue;
7535
7536                                 //
7537                                 // Mhm.  This is strage, because the Argument.Type is not the same as
7538                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
7539                                 //
7540                                 // Wonder if I will run into trouble for this.
7541                                 //
7542                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
7543                                 if (a.Expr == null)
7544                                         return null;
7545                         }
7546
7547                         eclass = ExprClass.Variable;
7548
7549                         return this;
7550                 }
7551
7552                 /// <summary>
7553                 ///    Emits the right opcode to load an object of Type `t'
7554                 ///    from an array of T
7555                 /// </summary>
7556                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
7557                 {
7558                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
7559                                 ig.Emit (OpCodes.Ldelem_U1);
7560                         else if (type == TypeManager.sbyte_type)
7561                                 ig.Emit (OpCodes.Ldelem_I1);
7562                         else if (type == TypeManager.short_type)
7563                                 ig.Emit (OpCodes.Ldelem_I2);
7564                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
7565                                 ig.Emit (OpCodes.Ldelem_U2);
7566                         else if (type == TypeManager.int32_type)
7567                                 ig.Emit (OpCodes.Ldelem_I4);
7568                         else if (type == TypeManager.uint32_type)
7569                                 ig.Emit (OpCodes.Ldelem_U4);
7570                         else if (type == TypeManager.uint64_type)
7571                                 ig.Emit (OpCodes.Ldelem_I8);
7572                         else if (type == TypeManager.int64_type)
7573                                 ig.Emit (OpCodes.Ldelem_I8);
7574                         else if (type == TypeManager.float_type)
7575                                 ig.Emit (OpCodes.Ldelem_R4);
7576                         else if (type == TypeManager.double_type)
7577                                 ig.Emit (OpCodes.Ldelem_R8);
7578                         else if (type == TypeManager.intptr_type)
7579                                 ig.Emit (OpCodes.Ldelem_I);
7580                         else if (TypeManager.IsEnumType (type)){
7581                                 EmitLoadOpcode (ig, TypeManager.EnumToUnderlying (type));
7582                         } else if (type.IsValueType){
7583                                 ig.Emit (OpCodes.Ldelema, type);
7584                                 ig.Emit (OpCodes.Ldobj, type);
7585                         } else
7586                                 ig.Emit (OpCodes.Ldelem_Ref);
7587                 }
7588
7589                 /// <summary>
7590                 ///    Returns the right opcode to store an object of Type `t'
7591                 ///    from an array of T.
7592                 /// </summary>
7593                 static public OpCode GetStoreOpcode (Type t, out bool is_stobj)
7594                 {
7595                         //Console.WriteLine (new System.Diagnostics.StackTrace ());
7596                         is_stobj = false;
7597                         t = TypeManager.TypeToCoreType (t);
7598                         if (TypeManager.IsEnumType (t))
7599                                 t = TypeManager.EnumToUnderlying (t);
7600                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
7601                             t == TypeManager.bool_type)
7602                                 return OpCodes.Stelem_I1;
7603                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type ||
7604                                  t == TypeManager.char_type)
7605                                 return OpCodes.Stelem_I2;
7606                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
7607                                 return OpCodes.Stelem_I4;
7608                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
7609                                 return OpCodes.Stelem_I8;
7610                         else if (t == TypeManager.float_type)
7611                                 return OpCodes.Stelem_R4;
7612                         else if (t == TypeManager.double_type)
7613                                 return OpCodes.Stelem_R8;
7614                         else if (t == TypeManager.intptr_type) {
7615                                 is_stobj = true;
7616                                 return OpCodes.Stobj;
7617                         } else if (t.IsValueType) {
7618                                 is_stobj = true;
7619                                 return OpCodes.Stobj;
7620                         } else
7621                                 return OpCodes.Stelem_Ref;
7622                 }
7623
7624                 MethodInfo FetchGetMethod ()
7625                 {
7626                         ModuleBuilder mb = CodeGen.Module.Builder;
7627                         int arg_count = ea.Arguments.Count;
7628                         Type [] args = new Type [arg_count];
7629                         MethodInfo get;
7630
7631                         for (int i = 0; i < arg_count; i++){
7632                                 //args [i++] = a.Type;
7633                                 args [i] = TypeManager.int32_type;
7634                         }
7635
7636                         get = mb.GetArrayMethod (
7637                                 ea.Expr.Type, "Get",
7638                                 CallingConventions.HasThis |
7639                                 CallingConventions.Standard,
7640                                 type, args);
7641                         return get;
7642                 }
7643
7644
7645                 MethodInfo FetchAddressMethod ()
7646                 {
7647                         ModuleBuilder mb = CodeGen.Module.Builder;
7648                         int arg_count = ea.Arguments.Count;
7649                         Type [] args = new Type [arg_count];
7650                         MethodInfo address;
7651                         Type ret_type;
7652
7653                         ret_type = TypeManager.GetReferenceType (type);
7654
7655                         for (int i = 0; i < arg_count; i++){
7656                                 //args [i++] = a.Type;
7657                                 args [i] = TypeManager.int32_type;
7658                         }
7659
7660                         address = mb.GetArrayMethod (
7661                                 ea.Expr.Type, "Address",
7662                                 CallingConventions.HasThis |
7663                                 CallingConventions.Standard,
7664                                 ret_type, args);
7665
7666                         return address;
7667                 }
7668
7669                 //
7670                 // Load the array arguments into the stack.
7671                 //
7672                 // If we have been requested to cache the values (cached_locations array
7673                 // initialized), then load the arguments the first time and store them
7674                 // in locals.  otherwise load from local variables.
7675                 //
7676                 void LoadArrayAndArguments (EmitContext ec)
7677                 {
7678                         ILGenerator ig = ec.ig;
7679
7680                         ea.Expr.Emit (ec);
7681                         foreach (Argument a in ea.Arguments){
7682                                 Type argtype = a.Expr.Type;
7683
7684                                 a.Expr.Emit (ec);
7685
7686                                 if (argtype == TypeManager.int64_type)
7687                                         ig.Emit (OpCodes.Conv_Ovf_I);
7688                                 else if (argtype == TypeManager.uint64_type)
7689                                         ig.Emit (OpCodes.Conv_Ovf_I_Un);
7690                         }
7691                 }
7692
7693                 public void Emit (EmitContext ec, bool leave_copy)
7694                 {
7695                         int rank = ea.Expr.Type.GetArrayRank ();
7696                         ILGenerator ig = ec.ig;
7697
7698                         if (!prepared) {
7699                                 LoadArrayAndArguments (ec);
7700
7701                                 if (rank == 1)
7702                                         EmitLoadOpcode (ig, type);
7703                                 else {
7704                                         MethodInfo method;
7705
7706                                         method = FetchGetMethod ();
7707                                         ig.Emit (OpCodes.Call, method);
7708                                 }
7709                         } else
7710                                 LoadFromPtr (ec.ig, this.type);
7711
7712                         if (leave_copy) {
7713                                 ec.ig.Emit (OpCodes.Dup);
7714                                 temp = new LocalTemporary (ec, this.type);
7715                                 temp.Store (ec);
7716                         }
7717                 }
7718
7719                 public override void Emit (EmitContext ec)
7720                 {
7721                         Emit (ec, false);
7722                 }
7723
7724                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
7725                 {
7726                         int rank = ea.Expr.Type.GetArrayRank ();
7727                         ILGenerator ig = ec.ig;
7728                         Type t = source.Type;
7729                         prepared = prepare_for_load;
7730
7731                         if (prepare_for_load) {
7732                                 AddressOf (ec, AddressOp.LoadStore);
7733                                 ec.ig.Emit (OpCodes.Dup);
7734                                 source.Emit (ec);
7735                                 if (leave_copy) {
7736                                         ec.ig.Emit (OpCodes.Dup);
7737                                         temp = new LocalTemporary (ec, this.type);
7738                                         temp.Store (ec);
7739                                 }
7740                                 StoreFromPtr (ec.ig, t);
7741
7742                                 if (temp != null)
7743                                         temp.Emit (ec);
7744
7745                                 return;
7746                         }
7747
7748                         LoadArrayAndArguments (ec);
7749
7750                         if (rank == 1) {
7751                                 bool is_stobj;
7752                                 OpCode op = GetStoreOpcode (t, out is_stobj);
7753                                 //
7754                                 // The stobj opcode used by value types will need
7755                                 // an address on the stack, not really an array/array
7756                                 // pair
7757                                 //
7758                                 if (is_stobj)
7759                                         ig.Emit (OpCodes.Ldelema, t);
7760
7761                                 source.Emit (ec);
7762                                 if (leave_copy) {
7763                                         ec.ig.Emit (OpCodes.Dup);
7764                                         temp = new LocalTemporary (ec, this.type);
7765                                         temp.Store (ec);
7766                                 }
7767
7768                                 if (is_stobj)
7769                                         ig.Emit (OpCodes.Stobj, t);
7770                                 else
7771                                         ig.Emit (op);
7772                         } else {
7773                                 ModuleBuilder mb = CodeGen.Module.Builder;
7774                                 int arg_count = ea.Arguments.Count;
7775                                 Type [] args = new Type [arg_count + 1];
7776                                 MethodInfo set;
7777
7778                                 source.Emit (ec);
7779                                 if (leave_copy) {
7780                                         ec.ig.Emit (OpCodes.Dup);
7781                                         temp = new LocalTemporary (ec, this.type);
7782                                         temp.Store (ec);
7783                                 }
7784
7785                                 for (int i = 0; i < arg_count; i++){
7786                                         //args [i++] = a.Type;
7787                                         args [i] = TypeManager.int32_type;
7788                                 }
7789
7790                                 args [arg_count] = type;
7791
7792                                 set = mb.GetArrayMethod (
7793                                         ea.Expr.Type, "Set",
7794                                         CallingConventions.HasThis |
7795                                         CallingConventions.Standard,
7796                                         TypeManager.void_type, args);
7797
7798                                 ig.Emit (OpCodes.Call, set);
7799                         }
7800
7801                         if (temp != null)
7802                                 temp.Emit (ec);
7803                 }
7804
7805                 public void AddressOf (EmitContext ec, AddressOp mode)
7806                 {
7807                         int rank = ea.Expr.Type.GetArrayRank ();
7808                         ILGenerator ig = ec.ig;
7809
7810                         LoadArrayAndArguments (ec);
7811
7812                         if (rank == 1){
7813                                 ig.Emit (OpCodes.Ldelema, type);
7814                         } else {
7815                                 MethodInfo address = FetchAddressMethod ();
7816                                 ig.Emit (OpCodes.Call, address);
7817                         }
7818                 }
7819         }
7820
7821
7822         class Indexers {
7823                 public ArrayList Properties;
7824                 static Hashtable map;
7825
7826                 public struct Indexer {
7827                         public readonly Type Type;
7828                         public readonly MethodInfo Getter, Setter;
7829
7830                         public Indexer (Type type, MethodInfo get, MethodInfo set)
7831                         {
7832                                 this.Type = type;
7833                                 this.Getter = get;
7834                                 this.Setter = set;
7835                         }
7836                 }
7837
7838                 static Indexers ()
7839                 {
7840                         map = new Hashtable ();
7841                 }
7842
7843                 Indexers ()
7844                 {
7845                         Properties = new ArrayList ();
7846                 }
7847
7848                 void Append (MemberInfo [] mi)
7849                 {
7850                         foreach (PropertyInfo property in mi){
7851                                 MethodInfo get, set;
7852
7853                                 get = property.GetGetMethod (true);
7854                                 set = property.GetSetMethod (true);
7855                                 Properties.Add (new Indexer (property.PropertyType, get, set));
7856                         }
7857                 }
7858
7859                 static private MemberInfo [] GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
7860                 {
7861                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
7862
7863                         MemberInfo [] mi = TypeManager.MemberLookup (
7864                                 caller_type, caller_type, lookup_type, MemberTypes.Property,
7865                                 BindingFlags.Public | BindingFlags.Instance |
7866                                 BindingFlags.DeclaredOnly, p_name, null);
7867
7868                         if (mi == null || mi.Length == 0)
7869                                 return null;
7870
7871                         return mi;
7872                 }
7873
7874                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
7875                 {
7876                         Indexers ix = (Indexers) map [lookup_type];
7877
7878                         if (ix != null)
7879                                 return ix;
7880
7881                         Type copy = lookup_type;
7882                         while (copy != TypeManager.object_type && copy != null){
7883                                 MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, copy);
7884
7885                                 if (mi != null){
7886                                         if (ix == null)
7887                                                 ix = new Indexers ();
7888
7889                                         ix.Append (mi);
7890                                 }
7891
7892                                 copy = copy.BaseType;
7893                         }
7894
7895                         if (!lookup_type.IsInterface)
7896                                 return ix;
7897
7898                         TypeExpr [] ifaces = TypeManager.GetInterfaces (lookup_type);
7899                         if (ifaces != null) {
7900                                 foreach (TypeExpr iface in ifaces) {
7901                                         Type itype = iface.Type;
7902                                         MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, itype);
7903                                         if (mi != null){
7904                                                 if (ix == null)
7905                                                         ix = new Indexers ();
7906
7907                                                 ix.Append (mi);
7908                                         }
7909                                 }
7910                         }
7911
7912                         return ix;
7913                 }
7914         }
7915
7916         /// <summary>
7917         ///   Expressions that represent an indexer call.
7918         /// </summary>
7919         public class IndexerAccess : Expression, IAssignMethod {
7920                 //
7921                 // Points to our "data" repository
7922                 //
7923                 MethodInfo get, set;
7924                 ArrayList set_arguments;
7925                 bool is_base_indexer;
7926
7927                 protected Type indexer_type;
7928                 protected Type current_type;
7929                 protected Expression instance_expr;
7930                 protected ArrayList arguments;
7931
7932                 public IndexerAccess (ElementAccess ea, Location loc)
7933                         : this (ea.Expr, false, loc)
7934                 {
7935                         this.arguments = ea.Arguments;
7936                 }
7937
7938                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
7939                                          Location loc)
7940                 {
7941                         this.instance_expr = instance_expr;
7942                         this.is_base_indexer = is_base_indexer;
7943                         this.eclass = ExprClass.Value;
7944                         this.loc = loc;
7945                 }
7946
7947                 protected virtual bool CommonResolve (EmitContext ec)
7948                 {
7949                         indexer_type = instance_expr.Type;
7950                         current_type = ec.ContainerType;
7951
7952                         return true;
7953                 }
7954
7955                 public override Expression DoResolve (EmitContext ec)
7956                 {
7957                         ArrayList AllGetters = new ArrayList();
7958                         if (!CommonResolve (ec))
7959                                 return null;
7960
7961                         //
7962                         // Step 1: Query for all `Item' *properties*.  Notice
7963                         // that the actual methods are pointed from here.
7964                         //
7965                         // This is a group of properties, piles of them.
7966
7967                         bool found_any = false, found_any_getters = false;
7968                         Type lookup_type = indexer_type;
7969
7970                         Indexers ilist;
7971                         ilist = Indexers.GetIndexersForType (current_type, lookup_type, loc);
7972                         if (ilist != null) {
7973                                 found_any = true;
7974                                 if (ilist.Properties != null) {
7975                                         foreach (Indexers.Indexer ix in ilist.Properties) {
7976                                                 if (ix.Getter != null)
7977                                                         AllGetters.Add(ix.Getter);
7978                                         }
7979                                 }
7980                         }
7981
7982                         if (AllGetters.Count > 0) {
7983                                 found_any_getters = true;
7984                                 get = (MethodInfo) Invocation.OverloadResolve (
7985                                         ec, new MethodGroupExpr (AllGetters, loc),
7986                                         arguments, false, loc);
7987                         }
7988
7989                         if (!found_any) {
7990                                 Report.Error (21, loc,
7991                                               "Type `" + TypeManager.CSharpName (indexer_type) +
7992                                               "' does not have any indexers defined");
7993                                 return null;
7994                         }
7995
7996                         if (!found_any_getters) {
7997                                 Error (154, "indexer can not be used in this context, because " +
7998                                        "it lacks a `get' accessor");
7999                                 return null;
8000                         }
8001
8002                         if (get == null) {
8003                                 Error (1501, "No Overload for method `this' takes `" +
8004                                        arguments.Count + "' arguments");
8005                                 return null;
8006                         }
8007
8008                         //
8009                         // Only base will allow this invocation to happen.
8010                         //
8011                         if (get.IsAbstract && this is BaseIndexerAccess){
8012                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (get));
8013                                 return null;
8014                         }
8015
8016                         type = get.ReturnType;
8017                         if (type.IsPointer && !ec.InUnsafe){
8018                                 UnsafeError (loc);
8019                                 return null;
8020                         }
8021
8022                         eclass = ExprClass.IndexerAccess;
8023                         return this;
8024                 }
8025
8026                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8027                 {
8028                         ArrayList AllSetters = new ArrayList();
8029                         if (!CommonResolve (ec))
8030                                 return null;
8031
8032                         bool found_any = false, found_any_setters = false;
8033
8034                         Indexers ilist = Indexers.GetIndexersForType (current_type, indexer_type, loc);
8035                         if (ilist != null) {
8036                                 found_any = true;
8037                                 if (ilist.Properties != null) {
8038                                         foreach (Indexers.Indexer ix in ilist.Properties) {
8039                                                 if (ix.Setter != null)
8040                                                         AllSetters.Add(ix.Setter);
8041                                         }
8042                                 }
8043                         }
8044                         if (AllSetters.Count > 0) {
8045                                 found_any_setters = true;
8046                                 set_arguments = (ArrayList) arguments.Clone ();
8047                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
8048                                 set = (MethodInfo) Invocation.OverloadResolve (
8049                                         ec, new MethodGroupExpr (AllSetters, loc),
8050                                         set_arguments, false, loc);
8051                         }
8052
8053                         if (!found_any) {
8054                                 Report.Error (21, loc,
8055                                               "Type `" + TypeManager.CSharpName (indexer_type) +
8056                                               "' does not have any indexers defined");
8057                                 return null;
8058                         }
8059
8060                         if (!found_any_setters) {
8061                                 Error (154, "indexer can not be used in this context, because " +
8062                                        "it lacks a `set' accessor");
8063                                 return null;
8064                         }
8065
8066                         if (set == null) {
8067                                 Error (1501, "No Overload for method `this' takes `" +
8068                                        arguments.Count + "' arguments");
8069                                 return null;
8070                         }
8071
8072                         //
8073                         // Only base will allow this invocation to happen.
8074                         //
8075                         if (set.IsAbstract && this is BaseIndexerAccess){
8076                                 Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (set));
8077                                 return null;
8078                         }
8079
8080                         //
8081                         // Now look for the actual match in the list of indexers to set our "return" type
8082                         //
8083                         type = TypeManager.void_type;   // default value
8084                         foreach (Indexers.Indexer ix in ilist.Properties){
8085                                 if (ix.Setter == set){
8086                                         type = ix.Type;
8087                                         break;
8088                                 }
8089                         }
8090
8091                         eclass = ExprClass.IndexerAccess;
8092                         return this;
8093                 }
8094
8095                 bool prepared = false;
8096                 LocalTemporary temp;
8097
8098                 public void Emit (EmitContext ec, bool leave_copy)
8099                 {
8100                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, get, arguments, loc, prepared, false);
8101                         if (leave_copy) {
8102                                 ec.ig.Emit (OpCodes.Dup);
8103                                 temp = new LocalTemporary (ec, Type);
8104                                 temp.Store (ec);
8105                         }
8106                 }
8107
8108                 //
8109                 // source is ignored, because we already have a copy of it from the
8110                 // LValue resolution and we have already constructed a pre-cached
8111                 // version of the arguments (ea.set_arguments);
8112                 //
8113                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8114                 {
8115                         prepared = prepare_for_load;
8116                         Argument a = (Argument) set_arguments [set_arguments.Count - 1];
8117
8118                         if (prepared) {
8119                                 source.Emit (ec);
8120                                 if (leave_copy) {
8121                                         ec.ig.Emit (OpCodes.Dup);
8122                                         temp = new LocalTemporary (ec, Type);
8123                                         temp.Store (ec);
8124                                 }
8125                         } else if (leave_copy) {
8126                                 temp = new LocalTemporary (ec, Type);
8127                                 source.Emit (ec);
8128                                 temp.Store (ec);
8129                                 a.Expr = temp;
8130                         }
8131
8132                         Invocation.EmitCall (ec, is_base_indexer, false, instance_expr, set, set_arguments, loc, false, prepared);
8133
8134                         if (temp != null)
8135                                 temp.Emit (ec);
8136                 }
8137
8138
8139                 public override void Emit (EmitContext ec)
8140                 {
8141                         Emit (ec, false);
8142                 }
8143         }
8144
8145         /// <summary>
8146         ///   The base operator for method names
8147         /// </summary>
8148         public class BaseAccess : Expression {
8149                 string member;
8150
8151                 public BaseAccess (string member, Location l)
8152                 {
8153                         this.member = member;
8154                         loc = l;
8155                 }
8156
8157                 public override Expression DoResolve (EmitContext ec)
8158                 {
8159                         Expression c = CommonResolve (ec);
8160
8161                         if (c == null)
8162                                 return null;
8163
8164                         //
8165                         // MethodGroups use this opportunity to flag an error on lacking ()
8166                         //
8167                         if (!(c is MethodGroupExpr))
8168                                 return c.Resolve (ec);
8169                         return c;
8170                 }
8171
8172                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
8173                 {
8174                         Expression c = CommonResolve (ec);
8175
8176                         if (c == null)
8177                                 return null;
8178
8179                         //
8180                         // MethodGroups use this opportunity to flag an error on lacking ()
8181                         //
8182                         if (! (c is MethodGroupExpr))
8183                                 return c.DoResolveLValue (ec, right_side);
8184
8185                         return c;
8186                 }
8187
8188                 Expression CommonResolve (EmitContext ec)
8189                 {
8190                         Expression member_lookup;
8191                         Type current_type = ec.ContainerType;
8192                         Type base_type = current_type.BaseType;
8193                         Expression e;
8194
8195                         if (ec.IsStatic){
8196                                 Error (1511, "Keyword base is not allowed in static method");
8197                                 return null;
8198                         }
8199
8200                         if (ec.IsFieldInitializer){
8201                                 Error (1512, "Keyword base is not available in the current context");
8202                                 return null;
8203                         }
8204
8205                         member_lookup = MemberLookup (ec, ec.ContainerType, null, base_type, member,
8206                                                       AllMemberTypes, AllBindingFlags, loc);
8207                         if (member_lookup == null) {
8208                                 MemberLookupFailed (ec, base_type, base_type, member, null, loc);
8209                                 return null;
8210                         }
8211
8212                         Expression left;
8213
8214                         if (ec.IsStatic)
8215                                 left = new TypeExpression (base_type, loc);
8216                         else
8217                                 left = ec.GetThis (loc);
8218
8219                         e = MemberAccess.ResolveMemberAccess (ec, member_lookup, left, loc, null);
8220
8221                         if (e is PropertyExpr){
8222                                 PropertyExpr pe = (PropertyExpr) e;
8223
8224                                 pe.IsBase = true;
8225                         }
8226
8227                         if (e is MethodGroupExpr)
8228                                 ((MethodGroupExpr) e).IsBase = true;
8229
8230                         return e;
8231                 }
8232
8233                 public override void Emit (EmitContext ec)
8234                 {
8235                         throw new Exception ("Should never be called");
8236                 }
8237         }
8238
8239         /// <summary>
8240         ///   The base indexer operator
8241         /// </summary>
8242         public class BaseIndexerAccess : IndexerAccess {
8243                 public BaseIndexerAccess (ArrayList args, Location loc)
8244                         : base (null, true, loc)
8245                 {
8246                         arguments = new ArrayList ();
8247                         foreach (Expression tmp in args)
8248                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
8249                 }
8250
8251                 protected override bool CommonResolve (EmitContext ec)
8252                 {
8253                         instance_expr = ec.GetThis (loc);
8254
8255                         current_type = ec.ContainerType.BaseType;
8256                         indexer_type = current_type;
8257
8258                         foreach (Argument a in arguments){
8259                                 if (!a.Resolve (ec, loc))
8260                                         return false;
8261                         }
8262
8263                         return true;
8264                 }
8265         }
8266
8267         /// <summary>
8268         ///   This class exists solely to pass the Type around and to be a dummy
8269         ///   that can be passed to the conversion functions (this is used by
8270         ///   foreach implementation to typecast the object return value from
8271         ///   get_Current into the proper type.  All code has been generated and
8272         ///   we only care about the side effect conversions to be performed
8273         ///
8274         ///   This is also now used as a placeholder where a no-action expression
8275         ///   is needed (the `New' class).
8276         /// </summary>
8277         public class EmptyExpression : Expression {
8278                 public EmptyExpression ()
8279                 {
8280                         type = TypeManager.object_type;
8281                         eclass = ExprClass.Value;
8282                         loc = Location.Null;
8283                 }
8284
8285                 public EmptyExpression (Type t)
8286                 {
8287                         type = t;
8288                         eclass = ExprClass.Value;
8289                         loc = Location.Null;
8290                 }
8291
8292                 public override Expression DoResolve (EmitContext ec)
8293                 {
8294                         return this;
8295                 }
8296
8297                 public override void Emit (EmitContext ec)
8298                 {
8299                         // nothing, as we only exist to not do anything.
8300                 }
8301
8302                 //
8303                 // This is just because we might want to reuse this bad boy
8304                 // instead of creating gazillions of EmptyExpressions.
8305                 // (CanImplicitConversion uses it)
8306                 //
8307                 public void SetType (Type t)
8308                 {
8309                         type = t;
8310                 }
8311         }
8312
8313         public class UserCast : Expression {
8314                 MethodBase method;
8315                 Expression source;
8316
8317                 public UserCast (MethodInfo method, Expression source, Location l)
8318                 {
8319                         this.method = method;
8320                         this.source = source;
8321                         type = method.ReturnType;
8322                         eclass = ExprClass.Value;
8323                         loc = l;
8324                 }
8325
8326                 public override Expression DoResolve (EmitContext ec)
8327                 {
8328                         //
8329                         // We are born fully resolved
8330                         //
8331                         return this;
8332                 }
8333
8334                 public override void Emit (EmitContext ec)
8335                 {
8336                         ILGenerator ig = ec.ig;
8337
8338                         source.Emit (ec);
8339
8340                         if (method is MethodInfo)
8341                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
8342                         else
8343                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
8344
8345                 }
8346         }
8347
8348         // <summary>
8349         //   This class is used to "construct" the type during a typecast
8350         //   operation.  Since the Type.GetType class in .NET can parse
8351         //   the type specification, we just use this to construct the type
8352         //   one bit at a time.
8353         // </summary>
8354         public class ComposedCast : TypeExpr {
8355                 Expression left;
8356                 string dim;
8357
8358                 public ComposedCast (Expression left, string dim, Location l)
8359                 {
8360                         this.left = left;
8361                         this.dim = dim;
8362                         loc = l;
8363                 }
8364
8365                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
8366                 {
8367                         Type ltype = ec.DeclSpace.ResolveType (left, false, loc);
8368                         if (ltype == null)
8369                                 return null;
8370
8371                         if ((ltype == TypeManager.void_type) && (dim != "*")) {
8372                                 Report.Error (1547, Location,
8373                                               "Keyword 'void' cannot be used in this context");
8374                                 return null;
8375                         }
8376
8377                         //
8378                         // ltype.Fullname is already fully qualified, so we can skip
8379                         // a lot of probes, and go directly to TypeManager.LookupType
8380                         //
8381                         string cname = ltype.FullName + dim;
8382                         type = TypeManager.LookupTypeDirect (cname);
8383                         if (type == null){
8384                                 //
8385                                 // For arrays of enumerations we are having a problem
8386                                 // with the direct lookup.  Need to investigate.
8387                                 //
8388                                 // For now, fall back to the full lookup in that case.
8389                                 //
8390                                 type = RootContext.LookupType (
8391                                         ec.DeclSpace, cname, false, loc);
8392
8393                                 if (type == null)
8394                                         return null;
8395                         }
8396
8397                         if (!ec.ResolvingTypeTree){
8398                                 //
8399                                 // If the above flag is set, this is being invoked from the ResolveType function.
8400                                 // Upper layers take care of the type validity in this context.
8401                                 //
8402                         if (!ec.InUnsafe && type.IsPointer){
8403                                 UnsafeError (loc);
8404                                 return null;
8405                         }
8406                         }
8407
8408                         eclass = ExprClass.Type;
8409                         return this;
8410                 }
8411
8412                 public override string Name {
8413                         get {
8414                                 return left + dim;
8415                         }
8416                 }
8417         }
8418
8419         //
8420         // This class is used to represent the address of an array, used
8421         // only by the Fixed statement, this is like the C "&a [0]" construct.
8422         //
8423         public class ArrayPtr : Expression {
8424                 Expression array;
8425
8426                 public ArrayPtr (Expression array, Location l)
8427                 {
8428                         Type array_type = TypeManager.GetElementType (array.Type);
8429
8430                         this.array = array;
8431
8432                         type = TypeManager.GetPointerType (array_type);
8433                         eclass = ExprClass.Value;
8434                         loc = l;
8435                 }
8436
8437                 public override void Emit (EmitContext ec)
8438                 {
8439                         ILGenerator ig = ec.ig;
8440
8441                         array.Emit (ec);
8442                         IntLiteral.EmitInt (ig, 0);
8443                         ig.Emit (OpCodes.Ldelema, TypeManager.GetElementType (array.Type));
8444                 }
8445
8446                 public override Expression DoResolve (EmitContext ec)
8447                 {
8448                         //
8449                         // We are born fully resolved
8450                         //
8451                         return this;
8452                 }
8453         }
8454
8455         //
8456         // Used by the fixed statement
8457         //
8458         public class StringPtr : Expression {
8459                 LocalBuilder b;
8460
8461                 public StringPtr (LocalBuilder b, Location l)
8462                 {
8463                         this.b = b;
8464                         eclass = ExprClass.Value;
8465                         type = TypeManager.char_ptr_type;
8466                         loc = l;
8467                 }
8468
8469                 public override Expression DoResolve (EmitContext ec)
8470                 {
8471                         // This should never be invoked, we are born in fully
8472                         // initialized state.
8473
8474                         return this;
8475                 }
8476
8477                 public override void Emit (EmitContext ec)
8478                 {
8479                         ILGenerator ig = ec.ig;
8480
8481                         ig.Emit (OpCodes.Ldloc, b);
8482                         ig.Emit (OpCodes.Conv_I);
8483                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
8484                         ig.Emit (OpCodes.Add);
8485                 }
8486         }
8487
8488         //
8489         // Implements the `stackalloc' keyword
8490         //
8491         public class StackAlloc : Expression {
8492                 Type otype;
8493                 Expression t;
8494                 Expression count;
8495
8496                 public StackAlloc (Expression type, Expression count, Location l)
8497                 {
8498                         t = type;
8499                         this.count = count;
8500                         loc = l;
8501                 }
8502
8503                 public override Expression DoResolve (EmitContext ec)
8504                 {
8505                         count = count.Resolve (ec);
8506                         if (count == null)
8507                                 return null;
8508
8509                         if (count.Type != TypeManager.int32_type){
8510                                 count = Convert.ImplicitConversionRequired (ec, count, TypeManager.int32_type, loc);
8511                                 if (count == null)
8512                                         return null;
8513                         }
8514
8515                         Constant c = count as Constant;
8516                         // TODO: because we don't have property IsNegative
8517                         if (c != null && c.ConvertToUInt () == null) {
8518                                 Report.Error (247, loc, "Cannot use a negative size with stackalloc");
8519                                 return null;
8520                         }
8521
8522                         if (ec.CurrentBranching.InCatch () ||
8523                             ec.CurrentBranching.InFinally (true)) {
8524                                 Error (255,
8525                                        "stackalloc can not be used in a catch or finally block");
8526                                 return null;
8527                         }
8528
8529                         otype = ec.DeclSpace.ResolveType (t, false, loc);
8530
8531                         if (otype == null)
8532                                 return null;
8533
8534                         if (!TypeManager.VerifyUnManaged (otype, loc))
8535                                 return null;
8536
8537                         type = TypeManager.GetPointerType (otype);
8538                         eclass = ExprClass.Value;
8539
8540                         return this;
8541                 }
8542
8543                 public override void Emit (EmitContext ec)
8544                 {
8545                         int size = GetTypeSize (otype);
8546                         ILGenerator ig = ec.ig;
8547
8548                         if (size == 0)
8549                                 ig.Emit (OpCodes.Sizeof, otype);
8550                         else
8551                                 IntConstant.EmitInt (ig, size);
8552                         count.Emit (ec);
8553                         ig.Emit (OpCodes.Mul);
8554                         ig.Emit (OpCodes.Localloc);
8555                 }
8556         }
8557 }