mcs/mbas/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 Ximian, Inc.
   8 //
   9 //
  10 #define USE_OLD
  11
  12 namespace Mono.MonoBASIC {
  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                 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);
  50
  51                         ec.ig.Emit (OpCodes.Call, mi);
  52                         return;
  53                 }
  54
  55                 static public Expression MakeSimpleCall (EmitContext ec, MethodGroupExpr mg,
  56                                                          Expression e, Location loc)
  57                 {
  58                         ArrayList args;
  59                         MethodBase method;
  60
  61                         args = new ArrayList (1);
  62                         args.Add (new Argument (e, Argument.AType.Expression));
  63                         method = Invocation.OverloadResolve (ec, (MethodGroupExpr) mg, args, loc);
  64
  65                         if (method == null)
  66                                 return null;
  67
  68                         return new StaticCallExpr ((MethodInfo) method, args, loc);
  69                 }
  70
  71                 public override void EmitStatement (EmitContext ec)
  72                 {
  73                         Emit (ec);
  74                         if (TypeManager.TypeToCoreType (type) != TypeManager.void_type)
  75                                 ec.ig.Emit (OpCodes.Pop);
  76                 }
  77         }
  78
  79         /// <summary>
  80         ///   Unary expressions.
  81         /// </summary>
  82         ///
  83         /// <remarks>
  84         ///   Unary implements unary expressions.   It derives from
  85         ///   ExpressionStatement becuase the pre/post increment/decrement
  86         ///   operators can be used in a statement context.
  87         /// </remarks>
  88         public class Unary : Expression {
  89                 public enum Operator : byte {
  90                         UnaryPlus, UnaryNegation, LogicalNot, OnesComplement,
  91                         Indirection, AddressOf,  TOP
  92                 }
  93
  94                 public Operator Oper;
  95                 public Expression Expr;
  96
  97                 public Unary (Operator op, Expression expr, Location loc)
  98                 {
  99                         this.Oper = op;
 100                         this.Expr = expr;
 101                         this.loc = loc;
 102                 }
 103
 104                 /// <summary>
 105                 ///   Returns a stringified representation of the Operator
 106                 /// </summary>
 107                 static public string OperName (Operator oper)
 108                 {
 109                         switch (oper){
 110                         case Operator.UnaryPlus:
 111                                 return "+";
 112                         case Operator.UnaryNegation:
 113                                 return "-";
 114                         case Operator.LogicalNot:
 115                                 return "!";
 116                         case Operator.OnesComplement:
 117                                 return "~";
 118                         case Operator.AddressOf:
 119                                 return "&";
 120                         case Operator.Indirection:
 121                                 return "*";
 122                         }
 123
 124                         return oper.ToString ();
 125                 }
 126
 127                 static string [] oper_names;
 128
 129                 static Unary ()
 130                 {
 131                         oper_names = new string [(int)Operator.TOP];
 132
 133                         oper_names [(int) Operator.UnaryPlus] = "op_UnaryPlus";
 134                         oper_names [(int) Operator.UnaryNegation] = "op_UnaryNegation";
 135                         oper_names [(int) Operator.LogicalNot] = "op_LogicalNot";
 136                         oper_names [(int) Operator.OnesComplement] = "op_OnesComplement";
 137                         oper_names [(int) Operator.Indirection] = "op_Indirection";
 138                         oper_names [(int) Operator.AddressOf] = "op_AddressOf";
 139                 }
 140
 141                 void Error23 (Type t)
 142                 {
 143                         Error (
 144                                 23, "Operator " + OperName (Oper) +
 145                                 " cannot be applied to operand of type '" +
 146                                 TypeManager.MonoBASIC_Name (t) + "'");
 147                 }
 148
 149                 /// <remarks>
 150                 ///   The result has been already resolved:
 151                 ///
 152                 ///   FIXME: a minus constant -128 sbyte cant be turned into a
 153                 ///   constant byte.
 154                 /// </remarks>
 155                 static Expression TryReduceNegative (Constant expr)
 156                 {
 157                         Expression e = null;
 158
 159                         if (expr is IntConstant)
 160                                 e = new IntConstant (-((IntConstant) expr).Value);
 161                         else if (expr is UIntConstant){
 162                                 uint value = ((UIntConstant) expr).Value;
 163
 164                                 if (value < 2147483649)
 165                                         return new IntConstant (-(int)value);
 166                                 else
 167                                         e = new LongConstant (value);
 168                         }
 169                         else if (expr is LongConstant)
 170                                 e = new LongConstant (-((LongConstant) expr).Value);
 171                         else if (expr is ULongConstant){
 172                                 ulong value = ((ULongConstant) expr).Value;
 173
 174                                 if (value < 9223372036854775809)
 175                                         return new LongConstant(-(long)value);
 176                         }
 177                         else if (expr is FloatConstant)
 178                                 e = new FloatConstant (-((FloatConstant) expr).Value);
 179                         else if (expr is DoubleConstant)
 180                                 e = new DoubleConstant (-((DoubleConstant) expr).Value);
 181                         else if (expr is DecimalConstant)
 182                                 e = new DecimalConstant (-((DecimalConstant) expr).Value);
 183                         else if (expr is ShortConstant)
 184                                 e = new IntConstant (-((ShortConstant) expr).Value);
 185                         else if (expr is UShortConstant)
 186                                 e = new IntConstant (-((UShortConstant) expr).Value);
 187                         return e;
 188                 }
 189
 190                 // <summary>
 191                 //   This routine will attempt to simplify the unary expression when the
 192                 //   argument is a constant.  The result is returned in 'result' and the
 193                 //   function returns true or false depending on whether a reduction
 194                 //   was performed or not
 195                 // </summary>
 196                 bool Reduce (EmitContext ec, Constant e, out Expression result)
 197                 {
 198                         Type expr_type = e.Type;
 199
 200                         switch (Oper){
 201                         case Operator.UnaryPlus:
 202                                 result = e;
 203                                 return true;
 204
 205                         case Operator.UnaryNegation:
 206                                 result = TryReduceNegative (e);
 207                                 return true;
 208
 209                         case Operator.LogicalNot:
 210                                 if (expr_type != TypeManager.bool_type) {
 211                                         result = null;
 212                                         Error23 (expr_type);
 213                                         return false;
 214                                 }
 215
 216                                 BoolConstant b = (BoolConstant) e;
 217                                 result = new BoolConstant (!(b.Value));
 218                                 return true;
 219
 220                         case Operator.OnesComplement:
 221                                 if (!((expr_type == TypeManager.int32_type) ||
 222                                       (expr_type == TypeManager.uint32_type) ||
 223                                       (expr_type == TypeManager.int64_type) ||
 224                                       (expr_type == TypeManager.uint64_type) ||
 225                                       (expr_type.IsSubclassOf (TypeManager.enum_type)))){
 226                                         result = null;
 227                                         Error23 (expr_type);
 228                                         return false;
 229                                 }
 230
 231                                 if (e is EnumConstant){
 232                                         EnumConstant enum_constant = (EnumConstant) e;
 233                                         Expression reduced;
 234
 235                                         if (Reduce (ec, enum_constant.Child, out reduced)){
 236                                                 result = new EnumConstant ((Constant) reduced, enum_constant.Type);
 237                                                 return true;
 238                                         } else {
 239                                                 result = null;
 240                                                 return false;
 241                                         }
 242                                 }
 243
 244                                 if (expr_type == TypeManager.int32_type){
 245                                         result = new IntConstant (~ ((IntConstant) e).Value);
 246                                 } else if (expr_type == TypeManager.uint32_type){
 247                                         result = new UIntConstant (~ ((UIntConstant) e).Value);
 248                                 } else if (expr_type == TypeManager.int64_type){
 249                                         result = new LongConstant (~ ((LongConstant) e).Value);
 250                                 } else if (expr_type == TypeManager.uint64_type){
 251                                         result = new ULongConstant (~ ((ULongConstant) e).Value);
 252                                 } else {
 253                                         result = null;
 254                                         Error23 (expr_type);
 255                                         return false;
 256                                 }
 257                                 return true;
 258
 259                         case Operator.AddressOf:
 260                                 result = this;
 261                                 return false;
 262
 263                         case Operator.Indirection:
 264                                 result = this;
 265                                 return false;
 266                         }
 267                         throw new Exception ("Can not constant fold: " + Oper.ToString());
 268                 }
 269
 270                 Expression ResolveOperator (EmitContext ec)
 271                 {
 272                         Type expr_type = Expr.Type;
 273
 274                         //
 275                         // Step 1: Perform Operator Overload location
 276                         //
 277                         Expression mg;
 278                         string op_name;
 279
 280                         op_name = oper_names [(int) Oper];
 281
 282                         mg = MemberLookup (ec, expr_type, op_name, MemberTypes.Method, AllBindingFlags, loc);
 283
 284                         if (mg != null) {
 285                                 Expression e = StaticCallExpr.MakeSimpleCall (
 286                                         ec, (MethodGroupExpr) mg, Expr, loc);
 287
 288                                 if (e == null){
 289                                         Error23 (expr_type);
 290                                         return null;
 291                                 }
 292
 293                                 return e;
 294                         }
 295
 296                         // Only perform numeric promotions on:
 297                         // +, -
 298
 299                         if (expr_type == null)
 300                                 return null;
 301
 302                         //
 303                         // Step 2: Default operations on CLI native types.
 304                         //
 305
 306                         // Attempt to use a constant folding operation.
 307                         if (Expr is Constant){
 308                                 Expression result;
 309
 310                                 if (Reduce (ec, (Constant) Expr, out result))
 311                                         return result;
 312                         }
 313
 314                         switch (Oper){
 315                         case Operator.LogicalNot:
 316                                 if (expr_type != TypeManager.bool_type) {
 317                                         Error23 (Expr.Type);
 318                                         return null;
 319                                 }
 320
 321                                 type = TypeManager.bool_type;
 322                                 return this;
 323
 324                         case Operator.OnesComplement:
 325                                 if (!((expr_type == TypeManager.int32_type) ||
 326                                       (expr_type == TypeManager.uint32_type) ||
 327                                       (expr_type == TypeManager.int64_type) ||
 328                                       (expr_type == TypeManager.uint64_type) ||
 329                                       (expr_type.IsSubclassOf (TypeManager.enum_type)))){
 330                                         Expression e;
 331
 332                                         e = ConvertImplicit (ec, Expr, TypeManager.int32_type, loc);
 333                                         if (e != null){
 334                                                 type = TypeManager.int32_type;
 335                                                 return this;
 336                                         }
 337                                         e = ConvertImplicit (ec, Expr, TypeManager.uint32_type, loc);
 338                                         if (e != null){
 339                                                 type = TypeManager.uint32_type;
 340                                                 return this;
 341                                         }
 342                                         e = ConvertImplicit (ec, Expr, TypeManager.int64_type, loc);
 343                                         if (e != null){
 344                                                 type = TypeManager.int64_type;
 345                                                 return this;
 346                                         }
 347                                         e = ConvertImplicit (ec, Expr, TypeManager.uint64_type, loc);
 348                                         if (e != null){
 349                                                 type = TypeManager.uint64_type;
 350                                                 return this;
 351                                         }
 352                                         Error23 (expr_type);
 353                                         return null;
 354                                 }
 355                                 type = expr_type;
 356                                 return this;
 357
 358                         case Operator.AddressOf:
 359                                 if (Expr.eclass != ExprClass.Variable){
 360                                         Error (211, "Cannot take the address of non-variables");
 361                                         return null;
 362                                 }
 363
 364                                 if (!ec.InUnsafe) {
 365                                         UnsafeError (loc);
 366                                         return null;
 367                                 }
 368
 369                                 if (!TypeManager.VerifyUnManaged (Expr.Type, loc)){
 370                                         return null;
 371                                 }
 372
 373                                 string ptr_type_name = Expr.Type.FullName + "*";
 374                                 type = TypeManager.LookupType (ptr_type_name);
 375
 376                                 return this;
 377
 378                         case Operator.Indirection:
 379                                 if (!ec.InUnsafe){
 380                                         UnsafeError (loc);
 381                                         return null;
 382                                 }
 383
 384                                 if (!expr_type.IsPointer){
 385                                         Error (
 386                                                 193,
 387                                                 "The * or -> operator can only be applied to pointers");
 388                                         return null;
 389                                 }
 390
 391                                 //
 392                                 // We create an Indirection expression, because
 393                                 // it can implement the IMemoryLocation.
 394                                 //
 395                                 return new Indirection (Expr, loc);
 396
 397                         case Operator.UnaryPlus:
 398                                 //
 399                                 // A plus in front of something is just a no-op, so return the child.
 400                                 //
 401                                 return Expr;
 402
 403                         case Operator.UnaryNegation:
 404                                 //
 405                                 // Deals with -literals
 406                                 // int     operator- (int x)
 407                                 // long    operator- (long x)
 408                                 // float   operator- (float f)
 409                                 // double  operator- (double d)
 410                                 // decimal operator- (decimal d)
 411                                 //
 412                                 Expression expr = null;
 413
 414                                 //
 415                                 // transform - - expr into expr
 416                                 //
 417                                 if (Expr is Unary){
 418                                         Unary unary = (Unary) Expr;
 419
 420                                         if (unary.Oper == Operator.UnaryNegation)
 421                                                 return unary.Expr;
 422                                 }
 423
 424                                 //
 425                                 // perform numeric promotions to int,
 426                                 // long, double.
 427                                 //
 428                                 //
 429                                 // The following is inneficient, because we call
 430                                 // ConvertImplicit too many times.
 431                                 //
 432                                 // It is also not clear if we should convert to Float
 433                                 // or Double initially.
 434                                 //
 435                                 if (expr_type == TypeManager.uint32_type){
 436                                         //
 437                                         // FIXME: handle exception to this rule that
 438                                         // permits the int value -2147483648 (-2^31) to
 439                                         // bt wrote as a decimal interger literal
 440                                         //
 441                                         type = TypeManager.int64_type;
 442                                         Expr = ConvertImplicit (ec, Expr, type, loc);
 443                                         return this;
 444                                 }
 445
 446                                 if (expr_type == TypeManager.uint64_type){
 447                                         //
 448                                         // FIXME: Handle exception of 'long value'
 449                                         // -92233720368547758087 (-2^63) to be wrote as
 450                                         // decimal integer literal.
 451                                         //
 452                                         Error23 (expr_type);
 453                                         return null;
 454                                 }
 455
 456                                 if (expr_type == TypeManager.float_type){
 457                                         type = expr_type;
 458                                         return this;
 459                                 }
 460
 461                                 expr = ConvertImplicit (ec, Expr, TypeManager.int32_type, loc);
 462                                 if (expr != null){
 463                                         Expr = expr;
 464                                         type = expr.Type;
 465                                         return this;
 466                                 }
 467
 468                                 expr = ConvertImplicit (ec, Expr, TypeManager.int64_type, loc);
 469                                 if (expr != null){
 470                                         Expr = expr;
 471                                         type = expr.Type;
 472                                         return this;
 473                                 }
 474
 475                                 expr = ConvertImplicit (ec, Expr, TypeManager.double_type, loc);
 476                                 if (expr != null){
 477                                         Expr = expr;
 478                                         type = expr.Type;
 479                                         return this;
 480                                 }
 481
 482                                 Error23 (expr_type);
 483                                 return null;
 484                         }
 485
 486                         Error (187, "No such operator '" + OperName (Oper) + "' defined for type '" +
 487                                TypeManager.MonoBASIC_Name (expr_type) + "'");
 488                         return null;
 489                 }
 490
 491                 public override Expression DoResolve (EmitContext ec)
 492                 {
 493                         if (Oper == Operator.AddressOf)
 494                                 Expr = Expr.ResolveLValue (ec, new EmptyExpression ());
 495                         else
 496                                 Expr = Expr.Resolve (ec);
 497
 498                         if (Expr == null)
 499                                 return null;
 500
 501                         eclass = ExprClass.Value;
 502                         return ResolveOperator (ec);
 503                 }
 504
 505                 public override void Emit (EmitContext ec)
 506                 {
 507                         ILGenerator ig = ec.ig;
 508                         Type expr_type = Expr.Type;
 509
 510                         switch (Oper) {
 511                         case Operator.UnaryPlus:
 512                                 throw new Exception ("This should be caught by Resolve");
 513
 514                         case Operator.UnaryNegation:
 515                                 Expr.Emit (ec);
 516                                 ig.Emit (OpCodes.Neg);
 517                                 break;
 518
 519                         case Operator.LogicalNot:
 520                                 Expr.Emit (ec);
 521                                 ig.Emit (OpCodes.Ldc_I4_0);
 522                                 ig.Emit (OpCodes.Ceq);
 523                                 break;
 524
 525                         case Operator.OnesComplement:
 526                                 Expr.Emit (ec);
 527                                 ig.Emit (OpCodes.Not);
 528                                 break;
 529
 530                         case Operator.AddressOf:
 531                                 ((IMemoryLocation)Expr).AddressOf (ec, AddressOp.LoadStore);
 532                                 break;
 533
 534                         default:
 535                                 throw new Exception ("This should not happen: Operator = "
 536                                                      + Oper.ToString ());
 537                         }
 538                 }
 539
 540                 /// <summary>
 541                 ///   This will emit the child expression for 'ec' avoiding the logical
 542                 ///   not.  The parent will take care of changing brfalse/brtrue
 543                 /// </summary>
 544                 public void EmitLogicalNot (EmitContext ec)
 545                 {
 546                         if (Oper != Operator.LogicalNot)
 547                                 throw new Exception ("EmitLogicalNot can only be called with !expr");
 548
 549                         Expr.Emit (ec);
 550                 }
 551
 552                 public override string ToString ()
 553                 {
 554                         return "Unary (" + Oper + ", " + Expr + ")";
 555                 }
 556
 557         }
 558
 559         //
 560         // Unary operators are turned into Indirection expressions
 561         // after semantic analysis (this is so we can take the address
 562         // of an indirection).
 563         //
 564         public class Indirection : Expression, IMemoryLocation, IAssignMethod {
 565                 Expression expr;
 566                 LocalTemporary temporary;
 567                 bool have_temporary;
 568
 569                 public Indirection (Expression expr, Location l)
 570                 {
 571                         this.expr = expr;
 572                         this.type = TypeManager.TypeToCoreType (expr.Type.GetElementType ());
 573                         eclass = ExprClass.Variable;
 574                         loc = l;
 575                 }
 576
 577                 void LoadExprValue (EmitContext ec)
 578                 {
 579                 }
 580
 581                 public override void Emit (EmitContext ec)
 582                 {
 583                         ILGenerator ig = ec.ig;
 584
 585                         if (temporary != null){
 586                                 if (have_temporary){
 587                                         temporary.Emit (ec);
 588                                         return;
 589                                 }
 590                                 expr.Emit (ec);
 591                                 ec.ig.Emit (OpCodes.Dup);
 592                                 temporary.Store (ec);
 593                                 have_temporary = true;
 594                         } else
 595                                 expr.Emit (ec);
 596
 597                         LoadFromPtr (ig, Type);
 598                 }
 599
 600                 public void EmitAssign (EmitContext ec, Expression source)
 601                 {
 602                         if (temporary != null){
 603                                 if (have_temporary){
 604                                         temporary.Emit (ec);
 605                                         return;
 606                                 }
 607                                 expr.Emit (ec);
 608                                 ec.ig.Emit (OpCodes.Dup);
 609                                 temporary.Store (ec);
 610                                 have_temporary = true;
 611                         } else
 612                                 expr.Emit (ec);
 613
 614                         source.Emit (ec);
 615                         StoreFromPtr (ec.ig, type);
 616                 }
 617
 618                 public void AddressOf (EmitContext ec, AddressOp Mode)
 619                 {
 620                         if (temporary != null){
 621                                 if (have_temporary){
 622                                         temporary.Emit (ec);
 623                                         return;
 624                                 }
 625                                 expr.Emit (ec);
 626                                 ec.ig.Emit (OpCodes.Dup);
 627                                 temporary.Store (ec);
 628                                 have_temporary = true;
 629                         } else
 630                                 expr.Emit (ec);
 631                 }
 632
 633                 public override Expression DoResolve (EmitContext ec)
 634                 {
 635                         //
 636                         // Born fully resolved
 637                         //
 638                         return this;
 639                 }
 640
 641                 public new void CacheTemporaries (EmitContext ec)
 642                 {
 643                         temporary = new LocalTemporary (ec, type);
 644                 }
 645         }
 646
 647         /// <summary>
 648         ///   Unary Mutator expressions (pre and post ++ and --)
 649         /// </summary>
 650         ///
 651         /// <remarks>
 652         ///   UnaryMutator implements ++ and -- expressions.   It derives from
 653         ///   ExpressionStatement becuase the pre/post increment/decrement
 654         ///   operators can be used in a statement context.
 655         ///
 656         /// FIXME: Idea, we could split this up in two classes, one simpler
 657         /// for the common case, and one with the extra fields for more complex
 658         /// classes (indexers require temporary access;  overloaded require method)
 659         ///
 660         /// Maybe we should have classes PreIncrement, PostIncrement, PreDecrement,
 661         /// PostDecrement, that way we could save the 'Mode' byte as well.
 662         /// </remarks>
 663         public class UnaryMutator : ExpressionStatement {
 664                 public enum Mode : byte {
 665                         PreIncrement, PreDecrement, PostIncrement, PostDecrement
 666                 }
 667
 668                 Mode mode;
 669                 Expression expr;
 670                 LocalTemporary temp_storage;
 671
 672                 //
 673                 // This is expensive for the simplest case.
 674                 //
 675                 Expression method;
 676
 677                 public UnaryMutator (Mode m, Expression e, Location l)
 678                 {
 679                         mode = m;
 680                         loc = l;
 681                         expr = e;
 682                 }
 683
 684                 static string OperName (Mode mode)
 685                 {
 686                         return (mode == Mode.PreIncrement || mode == Mode.PostIncrement) ?
 687                                 "++" : "--";
 688                 }
 689
 690                 void Error23 (Type t)
 691                 {
 692                         Error (
 693                                 23, "Operator " + OperName (mode) +
 694                                 " cannot be applied to operand of type '" +
 695                                 TypeManager.MonoBASIC_Name (t) + "'");
 696                 }
 697
 698                 /// <summary>
 699                 ///   Returns whether an object of type 't' can be incremented
 700                 ///   or decremented with add/sub (ie, basically whether we can
 701                 ///   use pre-post incr-decr operations on it, but it is not a
 702                 ///   System.Decimal, which we require operator overloading to catch)
 703                 /// </summary>
 704                 static bool IsIncrementableNumber (Type t)
 705                 {
 706                         return (t == TypeManager.sbyte_type) ||
 707                                 (t == TypeManager.byte_type) ||
 708                                 (t == TypeManager.short_type) ||
 709                                 (t == TypeManager.ushort_type) ||
 710                                 (t == TypeManager.int32_type) ||
 711                                 (t == TypeManager.uint32_type) ||
 712                                 (t == TypeManager.int64_type) ||
 713                                 (t == TypeManager.uint64_type) ||
 714                                 (t == TypeManager.char_type) ||
 715                                 (t.IsSubclassOf (TypeManager.enum_type)) ||
 716                                 (t == TypeManager.float_type) ||
 717                                 (t == TypeManager.double_type) ||
 718                                 (t.IsPointer && t != TypeManager.void_ptr_type);
 719                 }
 720
 721                 Expression ResolveOperator (EmitContext ec)
 722                 {
 723                         Type expr_type = expr.Type;
 724
 725                         //
 726                         // Step 1: Perform Operator Overload location
 727                         //
 728                         Expression mg;
 729                         string op_name;
 730
 731                         if (mode == Mode.PreIncrement || mode == Mode.PostIncrement)
 732                                 op_name = "op_Increment";
 733                         else
 734                                 op_name = "op_Decrement";
 735
 736                         mg = MemberLookup (ec, expr_type, op_name, MemberTypes.Method, AllBindingFlags, loc);
 737
 738                         if (mg == null && expr_type.BaseType != null)
 739                                 mg = MemberLookup (ec, expr_type.BaseType, op_name,
 740                                                    MemberTypes.Method, AllBindingFlags, loc);
 741
 742                         if (mg != null) {
 743                                 method = StaticCallExpr.MakeSimpleCall (
 744                                         ec, (MethodGroupExpr) mg, expr, loc);
 745
 746                                 type = method.Type;
 747                                 return this;
 748                         }
 749
 750                         //
 751                         // The operand of the prefix/postfix increment decrement operators
 752                         // should be an expression that is classified as a variable,
 753                         // a property access or an indexer access
 754                         //
 755                         type = expr_type;
 756                         if (expr.eclass == ExprClass.Variable){
 757                                 if (IsIncrementableNumber (expr_type) ||
 758                                     expr_type == TypeManager.decimal_type){
 759                                         return this;
 760                                 }
 761                         } else if (expr.eclass == ExprClass.IndexerAccess){
 762                                 IndexerAccess ia = (IndexerAccess) expr;
 763
 764                                 temp_storage = new LocalTemporary (ec, expr.Type);
 765
 766                                 expr = ia.ResolveLValue (ec, temp_storage);
 767                                 if (expr == null)
 768                                         return null;
 769
 770                                 return this;
 771                         } else if (expr.eclass == ExprClass.PropertyAccess){
 772                                 PropertyExpr pe = (PropertyExpr) expr;
 773
 774                                 if (pe.VerifyAssignable ())
 775                                         return this;
 776
 777                                 return null;
 778                         } else {
 779                                 expr.Error118 ("variable, indexer or property access");
 780                                 return null;
 781                         }
 782
 783                         Error (187, "No such operator '" + OperName (mode) + "' defined for type '" +
 784                                TypeManager.MonoBASIC_Name (expr_type) + "'");
 785                         return null;
 786                 }
 787
 788                 public override Expression DoResolve (EmitContext ec)
 789                 {
 790                         expr = expr.Resolve (ec);
 791
 792                         if (expr == null)
 793                                 return null;
 794
 795                         eclass = ExprClass.Value;
 796                         return ResolveOperator (ec);
 797                 }
 798
 799                 static int PtrTypeSize (Type t)
 800                 {
 801                         return GetTypeSize (t.GetElementType ());
 802                 }
 803
 804                 //
 805                 // Loads the proper "1" into the stack based on the type
 806                 //
 807                 static void LoadOne (ILGenerator ig, Type t)
 808                 {
 809                         if (t == TypeManager.uint64_type || t == TypeManager.int64_type)
 810                                 ig.Emit (OpCodes.Ldc_I8, 1L);
 811                         else if (t == TypeManager.double_type)
 812                                 ig.Emit (OpCodes.Ldc_R8, 1.0);
 813                         else if (t == TypeManager.float_type)
 814                                 ig.Emit (OpCodes.Ldc_R4, 1.0F);
 815                         else if (t.IsPointer){
 816                                 int n = PtrTypeSize (t);
 817
 818                                 if (n == 0)
 819                                         ig.Emit (OpCodes.Sizeof, t);
 820                                 else
 821                                         IntConstant.EmitInt (ig, n);
 822                         } else
 823                                 ig.Emit (OpCodes.Ldc_I4_1);
 824                 }
 825
 826
 827                 //
 828                 // FIXME: We need some way of avoiding the use of temp_storage
 829                 // for some types of storage (parameters, local variables,
 830                 // static fields) and single-dimension array access.
 831                 //
 832                 void EmitCode (EmitContext ec, bool is_expr)
 833                 {
 834                         ILGenerator ig = ec.ig;
 835                         IAssignMethod ia = (IAssignMethod) expr;
 836                         Type expr_type = expr.Type;
 837
 838                         if (temp_storage == null)
 839                                 temp_storage = new LocalTemporary (ec, expr_type);
 840
 841                         ia.CacheTemporaries (ec);
 842                         ig.Emit (OpCodes.Nop);
 843                         switch (mode){
 844                         case Mode.PreIncrement:
 845                         case Mode.PreDecrement:
 846                                 if (method == null){
 847                                         expr.Emit (ec);
 848
 849                                         LoadOne (ig, expr_type);
 850
 851                                         //
 852                                         // Select the opcode based on the check state (then the type)
 853                                         // and the actual operation
 854                                         //
 855                                         if (ec.CheckState){
 856                                                 if (expr_type == TypeManager.int32_type ||
 857                                                     expr_type == TypeManager.int64_type){
 858                                                         if (mode == Mode.PreDecrement)
 859                                                                 ig.Emit (OpCodes.Sub_Ovf);
 860                                                         else
 861                                                                 ig.Emit (OpCodes.Add_Ovf);
 862                                                 } else if (expr_type == TypeManager.uint32_type ||
 863                                                            expr_type == TypeManager.uint64_type){
 864                                                         if (mode == Mode.PreDecrement)
 865                                                                 ig.Emit (OpCodes.Sub_Ovf_Un);
 866                                                         else
 867                                                                 ig.Emit (OpCodes.Add_Ovf_Un);
 868                                                 } else {
 869                                                         if (mode == Mode.PreDecrement)
 870                                                                 ig.Emit (OpCodes.Sub_Ovf);
 871                                                         else
 872                                                                 ig.Emit (OpCodes.Add_Ovf);
 873                                                 }
 874                                         } else {
 875                                                 if (mode == Mode.PreDecrement)
 876                                                         ig.Emit (OpCodes.Sub);
 877                                                 else
 878                                                         ig.Emit (OpCodes.Add);
 879                                         }
 880                                 } else
 881                                         method.Emit (ec);
 882
 883                                 temp_storage.Store (ec);
 884                                 ia.EmitAssign (ec, temp_storage);
 885                                 if (is_expr)
 886                                         temp_storage.Emit (ec);
 887                                 break;
 888
 889                         case Mode.PostIncrement:
 890                         case Mode.PostDecrement:
 891                                 if (is_expr)
 892                                         expr.Emit (ec);
 893
 894                                 if (method == null){
 895                                         if (!is_expr)
 896                                                 expr.Emit (ec);
 897                                         else
 898                                                 ig.Emit (OpCodes.Dup);
 899
 900                                         LoadOne (ig, expr_type);
 901
 902                                         if (ec.CheckState){
 903                                                 if (expr_type == TypeManager.int32_type ||
 904                                                     expr_type == TypeManager.int64_type){
 905                                                         if (mode == Mode.PostDecrement)
 906                                                                 ig.Emit (OpCodes.Sub_Ovf);
 907                                                         else
 908                                                                 ig.Emit (OpCodes.Add_Ovf);
 909                                                 } else if (expr_type == TypeManager.uint32_type ||
 910                                                            expr_type == TypeManager.uint64_type){
 911                                                         if (mode == Mode.PostDecrement)
 912                                                                 ig.Emit (OpCodes.Sub_Ovf_Un);
 913                                                         else
 914                                                                 ig.Emit (OpCodes.Add_Ovf_Un);
 915                                                 } else {
 916                                                         if (mode == Mode.PostDecrement)
 917                                                                 ig.Emit (OpCodes.Sub_Ovf);
 918                                                         else
 919                                                                 ig.Emit (OpCodes.Add_Ovf);
 920                                                 }
 921                                         } else {
 922                                                 if (mode == Mode.PostDecrement)
 923                                                         ig.Emit (OpCodes.Sub);
 924                                                 else
 925                                                         ig.Emit (OpCodes.Add);
 926                                         }
 927                                 } else {
 928                                         method.Emit (ec);
 929                                 }
 930
 931                                 temp_storage.Store (ec);
 932                                 ia.EmitAssign (ec, temp_storage);
 933                                 break;
 934                         }
 935                 }
 936
 937                 public override void Emit (EmitContext ec)
 938                 {
 939                         EmitCode (ec, true);
 940
 941                 }
 942
 943                 public override void EmitStatement (EmitContext ec)
 944                 {
 945                         EmitCode (ec, false);
 946                 }
 947
 948         }
 949
 950         /// <summary>
 951         ///   Base class for the 'Is' and 'As' classes.
 952         /// </summary>
 953         ///
 954         /// <remarks>
 955         ///   FIXME: Split this in two, and we get to save the 'Operator' Oper
 956         ///   size.
 957         /// </remarks>
 958         public abstract class Probe : Expression {
 959                 public readonly Expression ProbeType;
 960                 protected Expression expr;
 961                 protected Type probe_type;
 962
 963                 public Probe (Expression expr, Expression probe_type, Location l)
 964                 {
 965                         ProbeType = probe_type;
 966                         loc = l;
 967                         this.expr = expr;
 968                 }
 969
 970                 public Expression Expr {
 971                         get {
 972                                 return expr;
 973                         }
 974                 }
 975
 976                 public override Expression DoResolve (EmitContext ec)
 977                 {
 978                         probe_type = ec.DeclSpace.ResolveType (ProbeType, false, loc);
 979
 980                         if (probe_type == null)
 981                                 return null;
 982
 983                         expr = expr.Resolve (ec);
 984
 985                         return this;
 986                 }
 987         }
 988
 989         /// <summary>
 990         ///   Implementation of the 'is' operator.
 991         /// </summary>
 992         public class Is : Probe {
 993                 public Is (Expression expr, Expression probe_type, Location l)
 994                         : base (expr, probe_type, l)
 995                 {
 996                 }
 997
 998                 enum Action {
 999                         AlwaysTrue, AlwaysNull, AlwaysFalse, LeaveOnStack, Probe
1000                 }
1001
1002                 Action action;
1003
1004                 public override void Emit (EmitContext ec)
1005                 {
1006                         ILGenerator ig = ec.ig;
1007
1008                         expr.Emit (ec);
1009
1010                         switch (action){
1011                         case Action.AlwaysFalse:
1012                                 ig.Emit (OpCodes.Pop);
1013                                 IntConstant.EmitInt (ig, 0);
1014                                 return;
1015                         case Action.AlwaysTrue:
1016                                 ig.Emit (OpCodes.Pop);
1017                                 ig.Emit (OpCodes.Nop);
1018                                 IntConstant.EmitInt (ig, 1);
1019                                 return;
1020                         case Action.LeaveOnStack:
1021                                 // the 'e != null' rule.
1022                                 return;
1023                         case Action.Probe:
1024                                 ig.Emit (OpCodes.Isinst, probe_type);
1025                                 ig.Emit (OpCodes.Ldnull);
1026                                 ig.Emit (OpCodes.Cgt_Un);
1027                                 return;
1028                         }
1029                         throw new Exception ("never reached");
1030                 }
1031
1032                 public override Expression DoResolve (EmitContext ec)
1033                 {
1034                         Expression e = base.DoResolve (ec);
1035
1036                         if ((e == null) || (expr == null))
1037                                 return null;
1038
1039                         Type etype = expr.Type;
1040                         bool warning_always_matches = false;
1041                         bool warning_never_matches = false;
1042
1043                         type = TypeManager.bool_type;
1044                         eclass = ExprClass.Value;
1045
1046                         //
1047                         // First case, if at compile time, there is an implicit conversion
1048                         // then e != null (objects) or true (value types)
1049                         //
1050                         e = ConvertImplicitStandard (ec, expr, probe_type, loc);
1051                         if (e != null){
1052                                 expr = e;
1053                                 if (etype.IsValueType)
1054                                         action = Action.AlwaysTrue;
1055                                 else
1056                                         action = Action.LeaveOnStack;
1057
1058                                 warning_always_matches = true;
1059                         } else if (ExplicitReferenceConversionExists (etype, probe_type)){
1060                                 //
1061                                 // Second case: explicit reference convresion
1062                                 //
1063                                 if (expr is NullLiteral)
1064                                         action = Action.AlwaysFalse;
1065                                 else
1066                                         action = Action.Probe;
1067                         } else {
1068                                 action = Action.AlwaysFalse;
1069                                 warning_never_matches = true;
1070                         }
1071
1072                         if (RootContext.WarningLevel >= 1){
1073                                 if (warning_always_matches)
1074                                         Warning (
1075                                                 183,
1076                                                 "The expression is always of type '" +
1077                                                 TypeManager.MonoBASIC_Name (probe_type) + "'");
1078                                 else if (warning_never_matches){
1079                                         if (!(probe_type.IsInterface || expr.Type.IsInterface))
1080                                                 Warning (
1081                                                         184,
1082                                                         "The expression is never of type '" +
1083                                                         TypeManager.MonoBASIC_Name (probe_type) + "'");
1084                                 }
1085                         }
1086
1087                         return this;
1088                 }
1089         }
1090
1091         /// <summary>
1092         ///   Implementation of the 'as' operator.
1093         /// </summary>
1094         public class As : Probe {
1095                 public As (Expression expr, Expression probe_type, Location l)
1096                         : base (expr, probe_type, l)
1097                 {
1098                 }
1099
1100                 bool do_isinst = false;
1101
1102                 public override void Emit (EmitContext ec)
1103                 {
1104                         ILGenerator ig = ec.ig;
1105
1106                         expr.Emit (ec);
1107
1108                         if (do_isinst)
1109                                 ig.Emit (OpCodes.Isinst, probe_type);
1110                 }
1111
1112                 static void Error_CannotConvertType (Type source, Type target, Location loc)
1113                 {
1114                         Report.Error (
1115                                 39, loc, "as operator can not convert from '" +
1116                                 TypeManager.MonoBASIC_Name (source) + "' to '" +
1117                                 TypeManager.MonoBASIC_Name (target) + "'");
1118                 }
1119
1120                 public override Expression DoResolve (EmitContext ec)
1121                 {
1122                         Expression e = base.DoResolve (ec);
1123
1124                         if (e == null)
1125                                 return null;
1126
1127                         type = probe_type;
1128                         eclass = ExprClass.Value;
1129                         Type etype = expr.Type;
1130
1131                         if (TypeManager.IsValueType (probe_type)){
1132                                 Report.Error (77, loc, "The as operator should be used with a reference type only (" +
1133                                               TypeManager.MonoBASIC_Name (probe_type) + " is a value type)");
1134                                 return null;
1135
1136                         }
1137
1138                         e = ConvertImplicit (ec, expr, probe_type, loc);
1139                         if (e != null){
1140                                 expr = e;
1141                                 do_isinst = false;
1142                                 return this;
1143                         }
1144
1145                         if (ExplicitReferenceConversionExists (etype, probe_type)){
1146                                 do_isinst = true;
1147                                 return this;
1148                         }
1149
1150                         Error_CannotConvertType (etype, probe_type, loc);
1151                         return null;
1152                 }
1153         }
1154
1155         /// <summary>
1156         ///   This represents a typecast in the source language.
1157         ///
1158         ///   FIXME: Cast expressions have an unusual set of parsing
1159         ///   rules, we need to figure those out.
1160         /// </summary>
1161         public class Cast : Expression {
1162                 Expression target_type;
1163                 Expression expr;
1164
1165                 public Cast (Expression cast_type, Expression expr, Location loc)
1166                 {
1167                         this.target_type = cast_type;
1168                         this.expr = expr;
1169                         this.loc = loc;
1170                 }
1171
1172                 public Expression TargetType {
1173                         get {
1174                                 return target_type;
1175                         }
1176                 }
1177
1178                 public Expression Expr {
1179                         get {
1180                                 return expr;
1181                         }
1182                         set {
1183                                 expr = value;
1184                         }
1185                 }
1186
1187                 /// <summary>
1188                 ///   Attempts to do a compile-time folding of a constant cast.
1189                 /// </summary>
1190                 Expression TryReduce (EmitContext ec, Type target_type)
1191                 {
1192                         if (expr is ByteConstant){
1193                                 byte v = ((ByteConstant) expr).Value;
1194
1195                                 if (target_type == TypeManager.sbyte_type)
1196                                         return new SByteConstant ((sbyte) v);
1197                                 if (target_type == TypeManager.short_type)
1198                                         return new ShortConstant ((short) v);
1199                                 if (target_type == TypeManager.ushort_type)
1200                                         return new UShortConstant ((ushort) v);
1201                                 if (target_type == TypeManager.int32_type)
1202                                         return new IntConstant ((int) v);
1203                                 if (target_type == TypeManager.uint32_type)
1204                                         return new UIntConstant ((uint) v);
1205                                 if (target_type == TypeManager.int64_type)
1206                                         return new LongConstant ((long) v);
1207                                 if (target_type == TypeManager.uint64_type)
1208                                         return new ULongConstant ((ulong) v);
1209                                 if (target_type == TypeManager.float_type)
1210                                         return new FloatConstant ((float) v);
1211                                 if (target_type == TypeManager.double_type)
1212                                         return new DoubleConstant ((double) v);
1213                                 if (target_type == TypeManager.char_type)
1214                                         return new CharConstant ((char) v);
1215                                 if (target_type == TypeManager.decimal_type)
1216                                         return new DecimalConstant ((decimal) v);
1217                         }
1218                         if (expr is SByteConstant){
1219                                 sbyte v = ((SByteConstant) expr).Value;
1220
1221                                 if (target_type == TypeManager.byte_type)
1222                                         return new ByteConstant ((byte) v);
1223                                 if (target_type == TypeManager.short_type)
1224                                         return new ShortConstant ((short) v);
1225                                 if (target_type == TypeManager.ushort_type)
1226                                         return new UShortConstant ((ushort) v);
1227                                 if (target_type == TypeManager.int32_type)
1228                                         return new IntConstant ((int) v);
1229                                 if (target_type == TypeManager.uint32_type)
1230                                         return new UIntConstant ((uint) v);
1231                                 if (target_type == TypeManager.int64_type)
1232                                         return new LongConstant ((long) v);
1233                                 if (target_type == TypeManager.uint64_type)
1234                                         return new ULongConstant ((ulong) v);
1235                                 if (target_type == TypeManager.float_type)
1236                                         return new FloatConstant ((float) v);
1237                                 if (target_type == TypeManager.double_type)
1238                                         return new DoubleConstant ((double) v);
1239                                 if (target_type == TypeManager.char_type)
1240                                         return new CharConstant ((char) v);
1241                                 if (target_type == TypeManager.decimal_type)
1242                                         return new DecimalConstant ((decimal) v);
1243                         }
1244                         if (expr is ShortConstant){
1245                                 short v = ((ShortConstant) expr).Value;
1246
1247                                 if (target_type == TypeManager.byte_type)
1248                                         return new ByteConstant ((byte) v);
1249                                 if (target_type == TypeManager.sbyte_type)
1250                                         return new SByteConstant ((sbyte) v);
1251                                 if (target_type == TypeManager.ushort_type)
1252                                         return new UShortConstant ((ushort) v);
1253                                 if (target_type == TypeManager.int32_type)
1254                                         return new IntConstant ((int) v);
1255                                 if (target_type == TypeManager.uint32_type)
1256                                         return new UIntConstant ((uint) v);
1257                                 if (target_type == TypeManager.int64_type)
1258                                         return new LongConstant ((long) v);
1259                                 if (target_type == TypeManager.uint64_type)
1260                                         return new ULongConstant ((ulong) v);
1261                                 if (target_type == TypeManager.float_type)
1262                                         return new FloatConstant ((float) v);
1263                                 if (target_type == TypeManager.double_type)
1264                                         return new DoubleConstant ((double) v);
1265                                 if (target_type == TypeManager.char_type)
1266                                         return new CharConstant ((char) v);
1267                                 if (target_type == TypeManager.decimal_type)
1268                                         return new DecimalConstant ((decimal) v);
1269                         }
1270                         if (expr is UShortConstant){
1271                                 ushort v = ((UShortConstant) expr).Value;
1272
1273                                 if (target_type == TypeManager.byte_type)
1274                                         return new ByteConstant ((byte) v);
1275                                 if (target_type == TypeManager.sbyte_type)
1276                                         return new SByteConstant ((sbyte) v);
1277                                 if (target_type == TypeManager.short_type)
1278                                         return new ShortConstant ((short) v);
1279                                 if (target_type == TypeManager.int32_type)
1280                                         return new IntConstant ((int) v);
1281                                 if (target_type == TypeManager.uint32_type)
1282                                         return new UIntConstant ((uint) v);
1283                                 if (target_type == TypeManager.int64_type)
1284                                         return new LongConstant ((long) v);
1285                                 if (target_type == TypeManager.uint64_type)
1286                                         return new ULongConstant ((ulong) v);
1287                                 if (target_type == TypeManager.float_type)
1288                                         return new FloatConstant ((float) v);
1289                                 if (target_type == TypeManager.double_type)
1290                                         return new DoubleConstant ((double) v);
1291                                 if (target_type == TypeManager.char_type)
1292                                         return new CharConstant ((char) v);
1293                                 if (target_type == TypeManager.decimal_type)
1294                                         return new DecimalConstant ((decimal) v);
1295                         }
1296                         if (expr is IntConstant){
1297                                 int v = ((IntConstant) expr).Value;
1298
1299                                 if (target_type == TypeManager.byte_type)
1300                                         return new ByteConstant ((byte) v);
1301                                 if (target_type == TypeManager.sbyte_type)
1302                                         return new SByteConstant ((sbyte) v);
1303                                 if (target_type == TypeManager.short_type)
1304                                         return new ShortConstant ((short) v);
1305                                 if (target_type == TypeManager.ushort_type)
1306                                         return new UShortConstant ((ushort) v);
1307                                 if (target_type == TypeManager.uint32_type)
1308                                         return new UIntConstant ((uint) v);
1309                                 if (target_type == TypeManager.int64_type)
1310                                         return new LongConstant ((long) v);
1311                                 if (target_type == TypeManager.uint64_type)
1312                                         return new ULongConstant ((ulong) v);
1313                                 if (target_type == TypeManager.float_type)
1314                                         return new FloatConstant ((float) v);
1315                                 if (target_type == TypeManager.double_type)
1316                                         return new DoubleConstant ((double) v);
1317                                 if (target_type == TypeManager.char_type)
1318                                         return new CharConstant ((char) v);
1319                                 if (target_type == TypeManager.decimal_type)
1320                                         return new DecimalConstant ((decimal) v);
1321                         }
1322                         if (expr is UIntConstant){
1323                                 uint v = ((UIntConstant) expr).Value;
1324
1325                                 if (target_type == TypeManager.byte_type)
1326                                         return new ByteConstant ((byte) v);
1327                                 if (target_type == TypeManager.sbyte_type)
1328                                         return new SByteConstant ((sbyte) v);
1329                                 if (target_type == TypeManager.short_type)
1330                                         return new ShortConstant ((short) v);
1331                                 if (target_type == TypeManager.ushort_type)
1332                                         return new UShortConstant ((ushort) v);
1333                                 if (target_type == TypeManager.int32_type)
1334                                         return new IntConstant ((int) v);
1335                                 if (target_type == TypeManager.int64_type)
1336                                         return new LongConstant ((long) v);
1337                                 if (target_type == TypeManager.uint64_type)
1338                                         return new ULongConstant ((ulong) v);
1339                                 if (target_type == TypeManager.float_type)
1340                                         return new FloatConstant ((float) v);
1341                                 if (target_type == TypeManager.double_type)
1342                                         return new DoubleConstant ((double) v);
1343                                 if (target_type == TypeManager.char_type)
1344                                         return new CharConstant ((char) v);
1345                                 if (target_type == TypeManager.decimal_type)
1346                                         return new DecimalConstant ((decimal) v);
1347                         }
1348                         if (expr is LongConstant){
1349                                 long v = ((LongConstant) expr).Value;
1350
1351                                 if (target_type == TypeManager.byte_type)
1352                                         return new ByteConstant ((byte) v);
1353                                 if (target_type == TypeManager.sbyte_type)
1354                                         return new SByteConstant ((sbyte) v);
1355                                 if (target_type == TypeManager.short_type)
1356                                         return new ShortConstant ((short) v);
1357                                 if (target_type == TypeManager.ushort_type)
1358                                         return new UShortConstant ((ushort) v);
1359                                 if (target_type == TypeManager.int32_type)
1360                                         return new IntConstant ((int) v);
1361                                 if (target_type == TypeManager.uint32_type)
1362                                         return new UIntConstant ((uint) v);
1363                                 if (target_type == TypeManager.uint64_type)
1364                                         return new ULongConstant ((ulong) v);
1365                                 if (target_type == TypeManager.float_type)
1366                                         return new FloatConstant ((float) v);
1367                                 if (target_type == TypeManager.double_type)
1368                                         return new DoubleConstant ((double) v);
1369                                 if (target_type == TypeManager.char_type)
1370                                         return new CharConstant ((char) v);
1371                                 if (target_type == TypeManager.decimal_type)
1372                                         return new DecimalConstant ((decimal) v);
1373                         }
1374                         if (expr is ULongConstant){
1375                                 ulong v = ((ULongConstant) expr).Value;
1376
1377                                 if (target_type == TypeManager.byte_type)
1378                                         return new ByteConstant ((byte) v);
1379                                 if (target_type == TypeManager.sbyte_type)
1380                                         return new SByteConstant ((sbyte) v);
1381                                 if (target_type == TypeManager.short_type)
1382                                         return new ShortConstant ((short) v);
1383                                 if (target_type == TypeManager.ushort_type)
1384                                         return new UShortConstant ((ushort) v);
1385                                 if (target_type == TypeManager.int32_type)
1386                                         return new IntConstant ((int) v);
1387                                 if (target_type == TypeManager.uint32_type)
1388                                         return new UIntConstant ((uint) v);
1389                                 if (target_type == TypeManager.int64_type)
1390                                         return new LongConstant ((long) v);
1391                                 if (target_type == TypeManager.float_type)
1392                                         return new FloatConstant ((float) v);
1393                                 if (target_type == TypeManager.double_type)
1394                                         return new DoubleConstant ((double) v);
1395                                 if (target_type == TypeManager.char_type)
1396                                         return new CharConstant ((char) v);
1397                                 if (target_type == TypeManager.decimal_type)
1398                                         return new DecimalConstant ((decimal) v);
1399                         }
1400                         if (expr is FloatConstant){
1401                                 float v = ((FloatConstant) expr).Value;
1402
1403                                 if (target_type == TypeManager.byte_type)
1404                                         return new ByteConstant ((byte) v);
1405                                 if (target_type == TypeManager.sbyte_type)
1406                                         return new SByteConstant ((sbyte) v);
1407                                 if (target_type == TypeManager.short_type)
1408                                         return new ShortConstant ((short) v);
1409                                 if (target_type == TypeManager.ushort_type)
1410                                         return new UShortConstant ((ushort) v);
1411                                 if (target_type == TypeManager.int32_type)
1412                                         return new IntConstant ((int) v);
1413                                 if (target_type == TypeManager.uint32_type)
1414                                         return new UIntConstant ((uint) v);
1415                                 if (target_type == TypeManager.int64_type)
1416                                         return new LongConstant ((long) v);
1417                                 if (target_type == TypeManager.uint64_type)
1418                                         return new ULongConstant ((ulong) v);
1419                                 if (target_type == TypeManager.double_type)
1420                                         return new DoubleConstant ((double) v);
1421                                 if (target_type == TypeManager.char_type)
1422                                         return new CharConstant ((char) v);
1423                                 if (target_type == TypeManager.decimal_type)
1424                                         return new DecimalConstant ((decimal) v);
1425                         }
1426                         if (expr is DoubleConstant){
1427                                 double v = ((DoubleConstant) expr).Value;
1428
1429                                 if (target_type == TypeManager.byte_type)
1430                                         return new ByteConstant ((byte) v);
1431                                 if (target_type == TypeManager.sbyte_type)
1432                                         return new SByteConstant ((sbyte) v);
1433                                 if (target_type == TypeManager.short_type)
1434                                         return new ShortConstant ((short) v);
1435                                 if (target_type == TypeManager.ushort_type)
1436                                         return new UShortConstant ((ushort) v);
1437                                 if (target_type == TypeManager.int32_type)
1438                                         return new IntConstant ((int) v);
1439                                 if (target_type == TypeManager.uint32_type)
1440                                         return new UIntConstant ((uint) v);
1441                                 if (target_type == TypeManager.int64_type)
1442                                         return new LongConstant ((long) v);
1443                                 if (target_type == TypeManager.uint64_type)
1444                                         return new ULongConstant ((ulong) v);
1445                                 if (target_type == TypeManager.float_type)
1446                                         return new FloatConstant ((float) v);
1447                                 if (target_type == TypeManager.char_type)
1448                                         return new CharConstant ((char) v);
1449                                 if (target_type == TypeManager.decimal_type)
1450                                         return new DecimalConstant ((decimal) v);
1451                         }
1452
1453                         return null;
1454                 }
1455
1456                 public override Expression DoResolve (EmitContext ec)
1457                 {
1458                         expr = expr.Resolve (ec);
1459                         if (expr == null)
1460                                 return null;
1461
1462                         int errors = Report.Errors;
1463
1464                         type = ec.DeclSpace.ResolveType (target_type, false, Location);
1465
1466                         if (type == null)
1467                                 return null;
1468
1469                         eclass = ExprClass.Value;
1470
1471                         if (expr is Constant){
1472                                 Expression e = TryReduce (ec, type);
1473
1474                                 if (e != null)
1475                                         return e;
1476                         }
1477
1478                         expr = ConvertExplicit (ec, expr, type, loc);
1479                         return expr;
1480                 }
1481
1482                 public override void Emit (EmitContext ec)
1483                 {
1484                         //
1485                         // This one will never happen
1486                         //
1487                         throw new Exception ("Should not happen");
1488                 }
1489         }
1490
1491         /// <summary>
1492         ///   Binary operators
1493         /// </summary>
1494         public class Binary : Expression {
1495                 public enum Operator : byte {
1496                         Multiply, Division, Modulus,
1497                         Addition, Subtraction,
1498                         LeftShift, RightShift,
1499                         LessThan, GreaterThan, LessThanOrEqual, GreaterThanOrEqual,
1500                         Equality, Inequality,
1501                         BitwiseAnd,
1502                         ExclusiveOr,
1503                         BitwiseOr,
1504                         LogicalAnd,
1505                         LogicalOr,
1506                         TOP
1507                 }
1508
1509                 Operator oper;
1510                 Expression left, right;
1511
1512                 //
1513                 // After resolution, method might contain the operator overload
1514                 // method.
1515                 //
1516                 protected MethodBase method;
1517                 ArrayList  Arguments;
1518
1519                 bool DelegateOperation;
1520
1521                 // This must be kept in sync with Operator!!!
1522                 static string [] oper_names;
1523
1524                 static Binary ()
1525                 {
1526                         oper_names = new string [(int) Operator.TOP];
1527
1528                         oper_names [(int) Operator.Multiply] = "op_Multiply";
1529                         oper_names [(int) Operator.Division] = "op_Division";
1530                         oper_names [(int) Operator.Modulus] = "op_Modulus";
1531                         oper_names [(int) Operator.Addition] = "op_Addition";
1532                         oper_names [(int) Operator.Subtraction] = "op_Subtraction";
1533                         oper_names [(int) Operator.LeftShift] = "op_LeftShift";
1534                         oper_names [(int) Operator.RightShift] = "op_RightShift";
1535                         oper_names [(int) Operator.LessThan] = "op_LessThan";
1536                         oper_names [(int) Operator.GreaterThan] = "op_GreaterThan";
1537                         oper_names [(int) Operator.LessThanOrEqual] = "op_LessThanOrEqual";
1538                         oper_names [(int) Operator.GreaterThanOrEqual] = "op_GreaterThanOrEqual";
1539                         oper_names [(int) Operator.Equality] = "op_Equality";
1540                         oper_names [(int) Operator.Inequality] = "op_Inequality";
1541                         oper_names [(int) Operator.BitwiseAnd] = "op_BitwiseAnd";
1542                         oper_names [(int) Operator.BitwiseOr] = "op_BitwiseOr";
1543                         oper_names [(int) Operator.ExclusiveOr] = "op_ExclusiveOr";
1544                         oper_names [(int) Operator.LogicalOr] = "op_LogicalOr";
1545                         oper_names [(int) Operator.LogicalAnd] = "op_LogicalAnd";
1546                 }
1547
1548                 public Binary (Operator oper, Expression left, Expression right, Location loc)
1549                 {
1550                         this.oper = oper;
1551                         this.left = left;
1552                         this.right = right;
1553                         this.loc = loc;
1554                 }
1555
1556                 public Operator Oper {
1557                         get {
1558                                 return oper;
1559                         }
1560                         set {
1561                                 oper = value;
1562                         }
1563                 }
1564
1565                 public Expression Left {
1566                         get {
1567                                 return left;
1568                         }
1569                         set {
1570                                 left = value;
1571                         }
1572                 }
1573
1574                 public Expression Right {
1575                         get {
1576                                 return right;
1577                         }
1578                         set {
1579                                 right = value;
1580                         }
1581                 }
1582
1583
1584                 /// <summary>
1585                 ///   Returns a stringified representation of the Operator
1586                 /// </summary>
1587                 static string OperName (Operator oper)
1588                 {
1589                         switch (oper){
1590                         case Operator.Multiply:
1591                                 return "*";
1592                         case Operator.Division:
1593                                 return "/";
1594                         case Operator.Modulus:
1595                                 return "%";
1596                         case Operator.Addition:
1597                                 return "+";
1598                         case Operator.Subtraction:
1599                                 return "-";
1600                         case Operator.LeftShift:
1601                                 return "<<";
1602                         case Operator.RightShift:
1603                                 return ">>";
1604                         case Operator.LessThan:
1605                                 return "<";
1606                         case Operator.GreaterThan:
1607                                 return ">";
1608                         case Operator.LessThanOrEqual:
1609                                 return "<=";
1610                         case Operator.GreaterThanOrEqual:
1611                                 return ">=";
1612                         case Operator.Equality:
1613                                 return "==";
1614                         case Operator.Inequality:
1615                                 return "!=";
1616                         case Operator.BitwiseAnd:
1617                                 return "&";
1618                         case Operator.BitwiseOr:
1619                                 return "|";
1620                         case Operator.ExclusiveOr:
1621                                 return "^";
1622                         case Operator.LogicalOr:
1623                                 return "||";
1624                         case Operator.LogicalAnd:
1625                                 return "&&";
1626                         }
1627
1628                         return oper.ToString ();
1629                 }
1630
1631                 public override string ToString ()
1632                 {
1633                         return "operator " + OperName (oper) + "(" + left.ToString () + ", " +
1634                                 right.ToString () + ")";
1635                 }
1636
1637                 Expression ForceConversion (EmitContext ec, Expression expr, Type target_type)
1638                 {
1639                         if (expr.Type == target_type)
1640                                 return expr;
1641
1642                         return ConvertImplicit (ec, expr, target_type, Location.Null);
1643                 }
1644
1645                 public static void Error_OperatorAmbiguous (Location loc, Operator oper, Type l, Type r)
1646                 {
1647                         Report.Error (
1648                                 34, loc, "Operator '" + OperName (oper)
1649                                 + "' is ambiguous on operands of type '"
1650                                 + TypeManager.MonoBASIC_Name (l) + "' "
1651                                 + "and '" + TypeManager.MonoBASIC_Name (r)
1652                                 + "'");
1653                 }
1654
1655                 //
1656                 // Note that handling the case l == Decimal || r == Decimal
1657                 // is taken care of by the Step 1 Operator Overload resolution.
1658                 //
1659                 bool DoNumericPromotions (EmitContext ec, Type l, Type r)
1660                 {
1661                         if (l == TypeManager.double_type || r == TypeManager.double_type){
1662                                 //
1663                                 // If either operand is of type double, the other operand is
1664                                 // conveted to type double.
1665                                 //
1666                                 if (r != TypeManager.double_type)
1667                                         right = ConvertImplicit (ec, right, TypeManager.double_type, loc);
1668                                 if (l != TypeManager.double_type)
1669                                         left = ConvertImplicit (ec, left, TypeManager.double_type, loc);
1670
1671                                 type = TypeManager.double_type;
1672                         } else if (l == TypeManager.float_type || r == TypeManager.float_type){
1673                                 //
1674                                 // if either operand is of type float, the other operand is
1675                                 // converted to type float.
1676                                 //
1677                                 if (r != TypeManager.double_type)
1678                                         right = ConvertImplicit (ec, right, TypeManager.float_type, loc);
1679                                 if (l != TypeManager.double_type)
1680                                         left = ConvertImplicit (ec, left, TypeManager.float_type, loc);
1681                                 type = TypeManager.float_type;
1682                         } else if (l == TypeManager.uint64_type || r == TypeManager.uint64_type){
1683                                 Expression e;
1684                                 Type other;
1685                                 //
1686                                 // If either operand is of type ulong, the other operand is
1687                                 // converted to type ulong.  or an error ocurrs if the other
1688                                 // operand is of type sbyte, short, int or long
1689                                 //
1690                                 if (l == TypeManager.uint64_type){
1691                                         if (r != TypeManager.uint64_type){
1692                                                 if (right is IntConstant){
1693                                                         IntConstant ic = (IntConstant) right;
1694
1695                                                         e = TryImplicitIntConversion (l, ic);
1696                                                         if (e != null)
1697                                                                 right = e;
1698                                                 } else if (right is LongConstant){
1699                                                         long ll = ((LongConstant) right).Value;
1700
1701                                                         if (ll > 0)
1702                                                                 right = new ULongConstant ((ulong) ll);
1703                                                 } else {
1704                                                         e = ImplicitNumericConversion (ec, right, l, loc);
1705                                                         if (e != null)
1706                                                                 right = e;
1707                                                 }
1708                                         }
1709                                         other = right.Type;
1710                                 } else {
1711                                         if (left is IntConstant){
1712                                                 e = TryImplicitIntConversion (r, (IntConstant) left);
1713                                                 if (e != null)
1714                                                         left = e;
1715                                         } else if (left is LongConstant){
1716                                                 long ll = ((LongConstant) left).Value;
1717
1718                                                 if (ll > 0)
1719                                                         left = new ULongConstant ((ulong) ll);
1720                                         } else {
1721                                                 e = ImplicitNumericConversion (ec, left, r, loc);
1722                                                 if (e != null)
1723                                                         left = e;
1724                                         }
1725                                         other = left.Type;
1726                                 }
1727
1728                                 if ((other == TypeManager.sbyte_type) ||
1729                                     (other == TypeManager.short_type) ||
1730                                     (other == TypeManager.int32_type) ||
1731                                     (other == TypeManager.int64_type))
1732                                         Error_OperatorAmbiguous (loc, oper, l, r);
1733                                 type = TypeManager.uint64_type;
1734                         } else if (l == TypeManager.int64_type || r == TypeManager.int64_type){
1735                                 //
1736                                 // If either operand is of type long, the other operand is converted
1737                                 // to type long.
1738                                 //
1739                                 if (l != TypeManager.int64_type)
1740                                         left = ConvertImplicit (ec, left, TypeManager.int64_type, loc);
1741                                 if (r != TypeManager.int64_type)
1742                                         right = ConvertImplicit (ec, right, TypeManager.int64_type, loc);
1743
1744                                 type = TypeManager.int64_type;
1745                         } else if (l == TypeManager.uint32_type || r == TypeManager.uint32_type){
1746                                 //
1747                                 // If either operand is of type uint, and the other
1748                                 // operand is of type sbyte, short or int, othe operands are
1749                                 // converted to type long.
1750                                 //
1751                                 Type other = null;
1752
1753                                 if (l == TypeManager.uint32_type){
1754                                         if (right is IntConstant){
1755                                                 IntConstant ic = (IntConstant) right;
1756                                                 int val = ic.Value;
1757
1758                                                 if (val >= 0)
1759                                                         right = new UIntConstant ((uint) val);
1760
1761                                                 type = l;
1762                                                 return true;
1763                                         }
1764                                         other = r;
1765                                 }
1766                                 else if (r == TypeManager.uint32_type){
1767                                         if (left is IntConstant){
1768                                                 IntConstant ic = (IntConstant) left;
1769                                                 int val = ic.Value;
1770
1771                                                 if (val >= 0)
1772                                                         left = new UIntConstant ((uint) val);
1773
1774                                                 type = r;
1775                                                 return true;
1776                                         }
1777
1778                                         other = l;
1779                                 }
1780
1781                                 if ((other == TypeManager.sbyte_type) ||
1782                                     (other == TypeManager.short_type) ||
1783                                     (other == TypeManager.int32_type)){
1784                                         left = ForceConversion (ec, left, TypeManager.int64_type);
1785                                         right = ForceConversion (ec, right, TypeManager.int64_type);
1786                                         type = TypeManager.int64_type;
1787                                 } else {
1788                                         //
1789                                         // if either operand is of type uint, the other
1790                                         // operand is converd to type uint
1791                                         //
1792                                         left = ForceConversion (ec, left, TypeManager.uint32_type);
1793                                         right = ForceConversion (ec, right, TypeManager.uint32_type);
1794                                         type = TypeManager.uint32_type;
1795                                 }
1796                         } else if (l == TypeManager.decimal_type || r == TypeManager.decimal_type){
1797                                 if (l != TypeManager.decimal_type)
1798                                         left = ConvertImplicit (ec, left, TypeManager.decimal_type, loc);
1799
1800                                 if (r != TypeManager.decimal_type)
1801                                         right = ConvertImplicit (ec, right, TypeManager.decimal_type, loc);
1802                                 type = TypeManager.decimal_type;
1803                         } else {
1804                                 left = ForceConversion (ec, left, TypeManager.int32_type);
1805                                 right = ForceConversion (ec, right, TypeManager.int32_type);
1806
1807                                 type = TypeManager.int32_type;
1808                         }
1809
1810                         return (left != null) && (right != null);
1811                 }
1812
1813                 static public void Error_OperatorCannotBeApplied (Location loc, string name, Type l, Type r)
1814                 {
1815                         Report.Error (19, loc,
1816                                "Operator " + name + " cannot be applied to operands of type '" +
1817                                TypeManager.MonoBASIC_Name (l) + "' and '" +
1818                                TypeManager.MonoBASIC_Name (r) + "'");
1819                 }
1820
1821                 void Error_OperatorCannotBeApplied ()
1822                 {
1823                         Error_OperatorCannotBeApplied (loc, OperName (oper), left.Type, right.Type);
1824                 }
1825
1826                 static bool is_32_or_64 (Type t)
1827                 {
1828                         return (t == TypeManager.int32_type || t == TypeManager.uint32_type ||
1829                                 t == TypeManager.int64_type || t == TypeManager.uint64_type);
1830                 }
1831
1832                 static bool is_unsigned (Type t)
1833                 {
1834                         return (t == TypeManager.uint32_type || t == TypeManager.uint64_type ||
1835                                 t == TypeManager.short_type || t == TypeManager.byte_type);
1836                 }
1837
1838                 Expression CheckShiftArguments (EmitContext ec)
1839                 {
1840                         Expression e;
1841                         Type l = left.Type;
1842                         Type r = right.Type;
1843
1844                         e = ForceConversion (ec, right, TypeManager.int32_type);
1845                         if (e == null){
1846                                 Error_OperatorCannotBeApplied ();
1847                                 return null;
1848                         }
1849                         right = e;
1850
1851                         if (((e = ConvertImplicit (ec, left, TypeManager.int32_type, loc)) != null) ||
1852                             ((e = ConvertImplicit (ec, left, TypeManager.uint32_type, loc)) != null) ||
1853                             ((e = ConvertImplicit (ec, left, TypeManager.int64_type, loc)) != null) ||
1854                             ((e = ConvertImplicit (ec, left, TypeManager.uint64_type, loc)) != null)){
1855                                 left = e;
1856                                 type = e.Type;
1857
1858                                 return this;
1859                         }
1860                         Error_OperatorCannotBeApplied ();
1861                         return null;
1862                 }
1863
1864                 Expression ResolveOperator (EmitContext ec)
1865                 {
1866                         Type l = left.Type;
1867                         Type r = right.Type;
1868
1869                         bool overload_failed = false;
1870
1871                         //
1872                         // Step 1: Perform Operator Overload location
1873                         //
1874                         Expression left_expr, right_expr;
1875
1876                         string op = oper_names [(int) oper];
1877
1878                         MethodGroupExpr union;
1879                         left_expr = MemberLookup (ec, l, op, MemberTypes.Method, AllBindingFlags, loc);
1880                         if (r != l){
1881                                 right_expr = MemberLookup (
1882                                         ec, r, op, MemberTypes.Method, AllBindingFlags, loc);
1883                                 union = Invocation.MakeUnionSet (left_expr, right_expr, loc);
1884                         } else
1885                                 union = (MethodGroupExpr) left_expr;
1886
1887                         if (union != null) {
1888                                 Arguments = new ArrayList ();
1889                                 Arguments.Add (new Argument (left, Argument.AType.Expression));
1890                                 Arguments.Add (new Argument (right, Argument.AType.Expression));
1891
1892                                 method = Invocation.OverloadResolve (ec, union, Arguments, Location.Null);
1893                                 if (method != null) {
1894                                         MethodInfo mi = (MethodInfo) method;
1895
1896                                         type = mi.ReturnType;
1897                                         return this;
1898                                 } else {
1899                                         overload_failed = true;
1900                                 }
1901                         }
1902
1903                         //
1904                         // Step 2: Default operations on CLI native types.
1905                         //
1906
1907                         //
1908                         // Step 0: String concatenation (because overloading will get this wrong)
1909                         //
1910                         if (oper == Operator.Addition){
1911                                 //
1912                                 // If any of the arguments is a string, cast to string
1913                                 //
1914
1915                                 if (l == TypeManager.string_type){
1916
1917                                         if (r == TypeManager.void_type) {
1918                                                 Error_OperatorCannotBeApplied ();
1919                                                 return null;
1920                                         }
1921
1922                                         if (r == TypeManager.string_type){
1923                                                 if (left is Constant && right is Constant){
1924                                                         StringConstant ls = (StringConstant) left;
1925                                                         StringConstant rs = (StringConstant) right;
1926
1927                                                         return new StringConstant (
1928                                                                 ls.Value + rs.Value);
1929                                                 }
1930
1931                                                 // string + string
1932                                                 method = TypeManager.string_concat_string_string;
1933                                         } else {
1934                                                 // string + object
1935                                                 method = TypeManager.string_concat_object_object;
1936                                                 right = ConvertImplicit (ec, right,
1937                                                                          TypeManager.object_type, loc);
1938                                                 if (right == null){
1939                                                         Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
1940                                                         return null;
1941                                                 }
1942                                         }
1943                                         type = TypeManager.string_type;
1944
1945                                         Arguments = new ArrayList ();
1946                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
1947                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
1948
1949                                         return this;
1950
1951                                 } else if (r == TypeManager.string_type){
1952                                         // object + string
1953
1954                                         if (l == TypeManager.void_type) {
1955                                                 Error_OperatorCannotBeApplied ();
1956                                                 return null;
1957                                         }
1958
1959                                         method = TypeManager.string_concat_object_object;
1960                                         left = ConvertImplicit (ec, left, TypeManager.object_type, loc);
1961                                         if (left == null){
1962                                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
1963                                                 return null;
1964                                         }
1965                                         Arguments = new ArrayList ();
1966                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
1967                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
1968
1969                                         type = TypeManager.string_type;
1970
1971                                         return this;
1972                                 }
1973
1974                                 //
1975                                 // Transform a + ( - b) into a - b
1976                                 //
1977                                 if (right is Unary){
1978                                         Unary right_unary = (Unary) right;
1979
1980                                         if (right_unary.Oper == Unary.Operator.UnaryNegation){
1981                                                 oper = Operator.Subtraction;
1982                                                 right = right_unary.Expr;
1983                                                 r = right.Type;
1984                                         }
1985                                 }
1986                         }
1987
1988                         if (oper == Operator.Equality || oper == Operator.Inequality){
1989                                 if (l == TypeManager.bool_type || r == TypeManager.bool_type){
1990                                         if (r != TypeManager.bool_type || l != TypeManager.bool_type){
1991                                                 Error_OperatorCannotBeApplied ();
1992                                                 return null;
1993                                         }
1994
1995                                         type = TypeManager.bool_type;
1996                                         return this;
1997                                 }
1998
1999                                 //
2000                                 // operator != (object a, object b)
2001                                 // operator == (object a, object b)
2002                                 //
2003                                 // For this to be used, both arguments have to be reference-types.
2004                                 // Read the rationale on the spec (14.9.6)
2005                                 //
2006                                 // Also, if at compile time we know that the classes do not inherit
2007                                 // one from the other, then we catch the error there.
2008                                 //
2009                                 if (!(l.IsValueType || r.IsValueType)){
2010                                         type = TypeManager.bool_type;
2011
2012                                         if (l == r)
2013                                                 return this;
2014
2015                                         if (l.IsSubclassOf (r) || r.IsSubclassOf (l))
2016                                                 return this;
2017
2018                                         //
2019                                         // Also, a standard conversion must exist from either one
2020                                         //
2021                                         if (!(StandardConversionExists (left, r) ||
2022                                               StandardConversionExists (right, l))){
2023                                                 Error_OperatorCannotBeApplied ();
2024                                                 return null;
2025                                         }
2026                                         //
2027                                         // We are going to have to convert to an object to compare
2028                                         //
2029                                         if (l != TypeManager.object_type)
2030                                                 left = new EmptyCast (left, TypeManager.object_type);
2031                                         if (r != TypeManager.object_type)
2032                                                 right = new EmptyCast (right, TypeManager.object_type);
2033
2034                                         //
2035                                         // FIXME: CSC here catches errors cs254 and cs252
2036                                         //
2037                                         return this;
2038                                 }
2039
2040                                 //
2041                                 // One of them is a valuetype, but the other one is not.
2042                                 //
2043                                 if (!l.IsValueType || !r.IsValueType) {
2044                                         Error_OperatorCannotBeApplied ();
2045                                         return null;
2046                                 }
2047                         }
2048
2049                         // Only perform numeric promotions on:
2050                         // +, -, *, /, %, &, |, ^, ==, !=, <, >, <=, >=
2051                         //
2052                         if (oper == Operator.Addition || oper == Operator.Subtraction) {
2053                                 if (l.IsSubclassOf (TypeManager.delegate_type) &&
2054                                     r.IsSubclassOf (TypeManager.delegate_type)) {
2055
2056                                         Arguments = new ArrayList ();
2057                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
2058                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
2059
2060                                         if (oper == Operator.Addition)
2061                                                 method = TypeManager.delegate_combine_delegate_delegate;
2062                                         else
2063                                                 method = TypeManager.delegate_remove_delegate_delegate;
2064
2065                                         if (l != r) {
2066                                                 Error_OperatorCannotBeApplied ();
2067                                                 return null;
2068                                         }
2069
2070                                         DelegateOperation = true;
2071                                         type = l;
2072                                         return this;
2073                                 }
2074
2075                                 //
2076                                 // Pointer arithmetic:
2077                                 //
2078                                 // T* operator + (T* x, int y);
2079                                 // T* operator + (T* x, uint y);
2080                                 // T* operator + (T* x, long y);
2081                                 // T* operator + (T* x, ulong y);
2082                                 //
2083                                 // T* operator + (int y,   T* x);
2084                                 // T* operator + (uint y,  T *x);
2085                                 // T* operator + (long y,  T *x);
2086                                 // T* operator + (ulong y, T *x);
2087                                 //
2088                                 // T* operator - (T* x, int y);
2089                                 // T* operator - (T* x, uint y);
2090                                 // T* operator - (T* x, long y);
2091                                 // T* operator - (T* x, ulong y);
2092                                 //
2093                                 // long operator - (T* x, T *y)
2094                                 //
2095                                 if (l.IsPointer){
2096                                         if (r.IsPointer && oper == Operator.Subtraction){
2097                                                 if (r == l)
2098                                                         return new PointerArithmetic (
2099                                                                 false, left, right, TypeManager.int64_type,
2100                                                                 loc);
2101                                         } else if (is_32_or_64 (r))
2102                                                 return new PointerArithmetic (
2103                                                         oper == Operator.Addition, left, right, l, loc);
2104                                 } else if (r.IsPointer && is_32_or_64 (l) && oper == Operator.Addition)
2105                                         return new PointerArithmetic (
2106                                                 true, right, left, r, loc);
2107                         }
2108
2109                         //
2110                         // Enumeration operators
2111                         //
2112                         bool lie = TypeManager.IsEnumType (l);
2113                         bool rie = TypeManager.IsEnumType (r);
2114                         if (lie || rie){
2115                                 Expression temp;
2116
2117                                 // U operator - (E e, E f)
2118                                 if (lie && rie && oper == Operator.Subtraction){
2119                                         if (l == r){
2120                                                 type = TypeManager.EnumToUnderlying (l);
2121                                                 return this;
2122                                         }
2123                                         Error_OperatorCannotBeApplied ();
2124                                         return null;
2125                                 }
2126
2127                                 //
2128                                 // operator + (E e, U x)
2129                                 // operator - (E e, U x)
2130                                 //
2131                                 if (oper == Operator.Addition || oper == Operator.Subtraction){
2132                                         Type enum_type = lie ? l : r;
2133                                         Type other_type = lie ? r : l;
2134                                         Type underlying_type = TypeManager.EnumToUnderlying (enum_type);
2135 ;
2136
2137                                         if (underlying_type != other_type){
2138                                                 Error_OperatorCannotBeApplied ();
2139                                                 return null;
2140                                         }
2141
2142                                         type = enum_type;
2143                                         return this;
2144                                 }
2145
2146                                 if (!rie){
2147                                         temp = ConvertImplicit (ec, right, l, loc);
2148                                         if (temp != null)
2149                                                 right = temp;
2150                                         else {
2151                                                 Error_OperatorCannotBeApplied ();
2152                                                 return null;
2153                                         }
2154                                 } if (!lie){
2155                                         temp = ConvertImplicit (ec, left, r, loc);
2156                                         if (temp != null){
2157                                                 left = temp;
2158                                                 l = r;
2159                                         } else {
2160                                                 Error_OperatorCannotBeApplied ();
2161                                                 return null;
2162                                         }
2163                                 }
2164
2165                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2166                                     oper == Operator.LessThanOrEqual || oper == Operator.LessThan ||
2167                                     oper == Operator.GreaterThanOrEqual || oper == Operator.GreaterThan){
2168                                         type = TypeManager.bool_type;
2169                                         return this;
2170                                 }
2171
2172                                 if (oper == Operator.BitwiseAnd ||
2173                                     oper == Operator.BitwiseOr ||
2174                                     oper == Operator.ExclusiveOr){
2175                                         type = l;
2176                                         return this;
2177                                 }
2178                                 Error_OperatorCannotBeApplied ();
2179                                 return null;
2180                         }
2181
2182                         if (oper == Operator.LeftShift || oper == Operator.RightShift)
2183                                 return CheckShiftArguments (ec);
2184
2185                         if (oper == Operator.LogicalOr || oper == Operator.LogicalAnd){
2186                                 if (l != TypeManager.bool_type || r != TypeManager.bool_type){
2187                                         Error_OperatorCannotBeApplied ();
2188                                         return null;
2189                                 }
2190
2191                                 type = TypeManager.bool_type;
2192                                 return this;
2193                         }
2194
2195                         //
2196                         // operator & (bool x, bool y)
2197                         // operator | (bool x, bool y)
2198                         // operator ^ (bool x, bool y)
2199                         //
2200                         if (l == TypeManager.bool_type && r == TypeManager.bool_type){
2201                                 if (oper == Operator.BitwiseAnd ||
2202                                     oper == Operator.BitwiseOr ||
2203                                     oper == Operator.ExclusiveOr){
2204                                         type = l;
2205                                         return this;
2206                                 }
2207                         }
2208
2209                         //
2210                         // Pointer comparison
2211                         //
2212                         if (l.IsPointer && r.IsPointer){
2213                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2214                                     oper == Operator.LessThan || oper == Operator.LessThanOrEqual ||
2215                                     oper == Operator.GreaterThan || oper == Operator.GreaterThanOrEqual){
2216                                         type = TypeManager.bool_type;
2217                                         return this;
2218                                 }
2219                         }
2220
2221                         //
2222                         // We are dealing with numbers
2223                         //
2224                         if (overload_failed){
2225                                 Error_OperatorCannotBeApplied ();
2226                                 return null;
2227                         }
2228
2229                         //
2230                         // This will leave left or right set to null if there is an error
2231                         //
2232                         DoNumericPromotions (ec, l, r);
2233                         if (left == null || right == null){
2234                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
2235                                 return null;
2236                         }
2237
2238                         //
2239                         // reload our cached types if required
2240                         //
2241                         l = left.Type;
2242                         r = right.Type;
2243
2244                         if (oper == Operator.BitwiseAnd ||
2245                             oper == Operator.BitwiseOr ||
2246                             oper == Operator.ExclusiveOr){
2247                                 if (l == r){
2248                                         if (!((l == TypeManager.int32_type) ||
2249                                               (l == TypeManager.uint32_type) ||
2250                                               (l == TypeManager.int64_type) ||
2251                                               (l == TypeManager.uint64_type)))
2252                                                 type = l;
2253                                 } else {
2254                                         Error_OperatorCannotBeApplied ();
2255                                         return null;
2256                                 }
2257                         }
2258
2259                         if (oper == Operator.Equality ||
2260                             oper == Operator.Inequality ||
2261                             oper == Operator.LessThanOrEqual ||
2262                             oper == Operator.LessThan ||
2263                             oper == Operator.GreaterThanOrEqual ||
2264                             oper == Operator.GreaterThan){
2265                                 type = TypeManager.bool_type;
2266                         }
2267
2268                         return this;
2269                 }
2270
2271                 public override Expression DoResolve (EmitContext ec)
2272                 {
2273                         left = left.Resolve (ec);
2274                         right = right.Resolve (ec);
2275
2276                         if (left == null || right == null)
2277                                 return null;
2278
2279                         if (left.Type == null)
2280                                 throw new Exception (
2281                                         "Resolve returned non null, but did not set the type! (" +
2282                                         left + ") at Line: " + loc.Row);
2283                         if (right.Type == null)
2284                                 throw new Exception (
2285                                         "Resolve returned non null, but did not set the type! (" +
2286                                         right + ") at Line: "+ loc.Row);
2287
2288                         eclass = ExprClass.Value;
2289
2290                         if (left is Constant && right is Constant){
2291                                 Expression e = ConstantFold.BinaryFold (
2292                                         ec, oper, (Constant) left, (Constant) right, loc);
2293                                 if (e != null)
2294                                         return e;
2295                         }
2296
2297                         return ResolveOperator (ec);
2298                 }
2299
2300                 /// <remarks>
2301                 ///   EmitBranchable is called from Statement.EmitBoolExpression in the
2302                 ///   context of a conditional bool expression.  This function will return
2303                 ///   false if it is was possible to use EmitBranchable, or true if it was.
2304                 ///
2305                 ///   The expression's code is generated, and we will generate a branch to 'target'
2306                 ///   if the resulting expression value is equal to isTrue
2307                 /// </remarks>
2308                 public bool EmitBranchable (EmitContext ec, Label target, bool onTrue)
2309                 {
2310                         if (method != null)
2311                                 return false;
2312
2313                         ILGenerator ig = ec.ig;
2314
2315                         //
2316                         // This is more complicated than it looks, but its just to avoid
2317                         // duplicated tests: basically, we allow ==, !=, >, <, >= and <=
2318                         // but on top of that we want for == and != to use a special path
2319                         // if we are comparing against null
2320                         //
2321                         if (oper == Operator.Equality || oper == Operator.Inequality){
2322                                 bool my_on_true = oper == Operator.Inequality ? onTrue : !onTrue;
2323
2324                                 if (left is NullLiteral){
2325                                         right.Emit (ec);
2326                                         if (my_on_true)
2327                                                 ig.Emit (OpCodes.Brtrue, target);
2328                                         else
2329                                                 ig.Emit (OpCodes.Brfalse, target);
2330                                         return true;
2331                                 } else if (right is NullLiteral){
2332                                         left.Emit (ec);
2333                                         if (my_on_true)
2334                                                 ig.Emit (OpCodes.Brtrue, target);
2335                                         else
2336                                                 ig.Emit (OpCodes.Brfalse, target);
2337                                         return true;
2338                                 }
2339                         } else if (!(oper == Operator.LessThan ||
2340                                       oper == Operator.GreaterThan ||
2341                                       oper == Operator.LessThanOrEqual ||
2342                                       oper == Operator.GreaterThanOrEqual))
2343                                 return false;
2344
2345
2346
2347                         left.Emit (ec);
2348                         right.Emit (ec);
2349
2350                         bool isUnsigned = is_unsigned (left.Type);
2351
2352                         switch (oper){
2353                         case Operator.Equality:
2354                                 if (onTrue)
2355                                         ig.Emit (OpCodes.Beq, target);
2356                                 else
2357                                         ig.Emit (OpCodes.Bne_Un, target);
2358                                 break;
2359
2360                         case Operator.Inequality:
2361                                 if (onTrue)
2362                                         ig.Emit (OpCodes.Bne_Un, target);
2363                                 else
2364                                         ig.Emit (OpCodes.Beq, target);
2365                                 break;
2366
2367                         case Operator.LessThan:
2368                                 if (onTrue)
2369                                         if (isUnsigned)
2370                                                 ig.Emit (OpCodes.Blt_Un, target);
2371                                         else
2372                                                 ig.Emit (OpCodes.Blt, target);
2373                                 else
2374                                         if (isUnsigned)
2375                                                 ig.Emit (OpCodes.Bge_Un, target);
2376                                         else
2377                                                 ig.Emit (OpCodes.Bge, target);
2378                                 break;
2379
2380                         case Operator.GreaterThan:
2381                                 if (onTrue)
2382                                         if (isUnsigned)
2383                                                 ig.Emit (OpCodes.Bgt_Un, target);
2384                                         else
2385                                                 ig.Emit (OpCodes.Bgt, target);
2386                                 else
2387                                         if (isUnsigned)
2388                                                 ig.Emit (OpCodes.Ble_Un, target);
2389                                         else
2390                                                 ig.Emit (OpCodes.Ble, target);
2391                                 break;
2392
2393                         case Operator.LessThanOrEqual:
2394                                 if (onTrue)
2395                                         if (isUnsigned)
2396                                                 ig.Emit (OpCodes.Ble_Un, target);
2397                                         else
2398                                                 ig.Emit (OpCodes.Ble, target);
2399                                 else
2400                                         if (isUnsigned)
2401                                                 ig.Emit (OpCodes.Bgt_Un, target);
2402                                         else
2403                                                 ig.Emit (OpCodes.Bgt, target);
2404                                 break;
2405
2406
2407                         case Operator.GreaterThanOrEqual:
2408                                 if (onTrue)
2409                                         if (isUnsigned)
2410                                                 ig.Emit (OpCodes.Bge_Un, target);
2411                                         else
2412                                                 ig.Emit (OpCodes.Bge, target);
2413                                 else
2414                                         if (isUnsigned)
2415                                                 ig.Emit (OpCodes.Blt_Un, target);
2416                                         else
2417                                                 ig.Emit (OpCodes.Blt, target);
2418                                 break;
2419
2420                         default:
2421                                 return false;
2422                         }
2423
2424                         return true;
2425                 }
2426
2427                 public override void Emit (EmitContext ec)
2428                 {
2429                         ILGenerator ig = ec.ig;
2430                         Type l = left.Type;
2431                         Type r = right.Type;
2432                         OpCode opcode;
2433
2434                         if (method != null) {
2435
2436                                 // Note that operators are static anyway
2437
2438                                 if (Arguments != null)
2439                                         Invocation.EmitArguments (ec, method, Arguments);
2440
2441                                 if (method is MethodInfo)
2442                                         ig.Emit (OpCodes.Call, (MethodInfo) method);
2443                                 else
2444                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
2445
2446                                 if (DelegateOperation)
2447                                         ig.Emit (OpCodes.Castclass, type);
2448
2449                                 return;
2450                         }
2451
2452                         //
2453                         // Handle short-circuit operators differently
2454                         // than the rest
2455                         //
2456                         if (oper == Operator.LogicalAnd){
2457                                 Label load_zero = ig.DefineLabel ();
2458                                 Label end = ig.DefineLabel ();
2459
2460                                 left.Emit (ec);
2461                                 ig.Emit (OpCodes.Brfalse, load_zero);
2462                                 right.Emit (ec);
2463                                 ig.Emit (OpCodes.Br, end);
2464                                 ig.MarkLabel (load_zero);
2465                                 ig.Emit (OpCodes.Ldc_I4_0);
2466                                 ig.MarkLabel (end);
2467                                 return;
2468                         } else if (oper == Operator.LogicalOr){
2469                                 Label load_one = ig.DefineLabel ();
2470                                 Label end = ig.DefineLabel ();
2471
2472                                 left.Emit (ec);
2473                                 ig.Emit (OpCodes.Brtrue, load_one);
2474                                 right.Emit (ec);
2475                                 ig.Emit (OpCodes.Br, end);
2476                                 ig.MarkLabel (load_one);
2477                                 ig.Emit (OpCodes.Ldc_I4_1);
2478                                 ig.MarkLabel (end);
2479                                 return;
2480                         }
2481
2482                         left.Emit (ec);
2483                         right.Emit (ec);
2484
2485                         switch (oper){
2486                         case Operator.Multiply:
2487                                 if (ec.CheckState){
2488                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2489                                                 opcode = OpCodes.Mul_Ovf;
2490                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2491                                                 opcode = OpCodes.Mul_Ovf_Un;
2492                                         else
2493                                                 opcode = OpCodes.Mul;
2494                                 } else
2495                                         opcode = OpCodes.Mul;
2496
2497                                 break;
2498
2499                         case Operator.Division:
2500                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2501                                         opcode = OpCodes.Div_Un;
2502                                 else
2503                                         opcode = OpCodes.Div;
2504                                 break;
2505
2506                         case Operator.Modulus:
2507                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2508                                         opcode = OpCodes.Rem_Un;
2509                                 else
2510                                         opcode = OpCodes.Rem;
2511                                 break;
2512
2513                         case Operator.Addition:
2514                                 if (ec.CheckState){
2515                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2516                                                 opcode = OpCodes.Add_Ovf;
2517                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2518                                                 opcode = OpCodes.Add_Ovf_Un;
2519                                         else
2520                                                 opcode = OpCodes.Add;
2521                                 } else
2522                                         opcode = OpCodes.Add;
2523                                 break;
2524
2525                         case Operator.Subtraction:
2526                                 if (ec.CheckState){
2527                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2528                                                 opcode = OpCodes.Sub_Ovf;
2529                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2530                                                 opcode = OpCodes.Sub_Ovf_Un;
2531                                         else
2532                                                 opcode = OpCodes.Sub;
2533                                 } else
2534                                         opcode = OpCodes.Sub;
2535                                 break;
2536
2537                         case Operator.RightShift:
2538                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2539                                         opcode = OpCodes.Shr_Un;
2540                                 else
2541                                         opcode = OpCodes.Shr;
2542                                 break;
2543
2544                         case Operator.LeftShift:
2545                                 opcode = OpCodes.Shl;
2546                                 break;
2547
2548                         case Operator.Equality:
2549                                 opcode = OpCodes.Ceq;
2550                                 break;
2551
2552                         case Operator.Inequality:
2553                                 ec.ig.Emit (OpCodes.Ceq);
2554                                 ec.ig.Emit (OpCodes.Ldc_I4_0);
2555
2556                                 opcode = OpCodes.Ceq;
2557                                 break;
2558
2559                         case Operator.LessThan:
2560                                 opcode = OpCodes.Clt;
2561                                 break;
2562
2563                         case Operator.GreaterThan:
2564                                 opcode = OpCodes.Cgt;
2565                                 break;
2566
2567                         case Operator.LessThanOrEqual:
2568                                 ec.ig.Emit (OpCodes.Cgt);
2569                                 ec.ig.Emit (OpCodes.Ldc_I4_0);
2570
2571                                 opcode = OpCodes.Ceq;
2572                                 break;
2573
2574                         case Operator.GreaterThanOrEqual:
2575                                 ec.ig.Emit (OpCodes.Clt);
2576                                 ec.ig.Emit (OpCodes.Ldc_I4_1);
2577
2578                                 opcode = OpCodes.Sub;
2579                                 break;
2580
2581                         case Operator.BitwiseOr:
2582                                 opcode = OpCodes.Or;
2583                                 break;
2584
2585                         case Operator.BitwiseAnd:
2586                                 opcode = OpCodes.And;
2587                                 break;
2588
2589                         case Operator.ExclusiveOr:
2590                                 opcode = OpCodes.Xor;
2591                                 break;
2592
2593                         default:
2594                                 throw new Exception ("This should not happen: Operator = "
2595                                                      + oper.ToString ());
2596                         }
2597
2598                         ig.Emit (opcode);
2599                 }
2600
2601                 public bool IsBuiltinOperator {
2602                         get {
2603                                 return method == null;
2604                         }
2605                 }
2606         }
2607
2608         public class PointerArithmetic : Expression {
2609                 Expression left, right;
2610                 bool is_add;
2611
2612                 //
2613                 // We assume that 'l' is always a pointer
2614                 //
2615                 public PointerArithmetic (bool is_addition, Expression l, Expression r, Type t,
2616                                           Location loc)
2617                 {
2618                         type = t;
2619                         eclass = ExprClass.Variable;
2620                         this.loc = loc;
2621                         left = l;
2622                         right = r;
2623                         is_add = is_addition;
2624                 }
2625
2626                 public override Expression DoResolve (EmitContext ec)
2627                 {
2628                         //
2629                         // We are born fully resolved
2630                         //
2631                         return this;
2632                 }
2633
2634                 public override void Emit (EmitContext ec)
2635                 {
2636                         Type op_type = left.Type;
2637                         ILGenerator ig = ec.ig;
2638                         int size = GetTypeSize (op_type.GetElementType ());
2639
2640                         if (right.Type.IsPointer){
2641                                 //
2642                                 // handle (pointer - pointer)
2643                                 //
2644                                 left.Emit (ec);
2645                                 right.Emit (ec);
2646                                 ig.Emit (OpCodes.Sub);
2647
2648                                 if (size != 1){
2649                                         if (size == 0)
2650                                                 ig.Emit (OpCodes.Sizeof, op_type);
2651                                         else
2652                                                 IntLiteral.EmitInt (ig, size);
2653                                         ig.Emit (OpCodes.Div);
2654                                 }
2655                                 ig.Emit (OpCodes.Conv_I8);
2656                         } else {
2657                                 //
2658                                 // handle + and - on (pointer op int)
2659                                 //
2660                                 left.Emit (ec);
2661                                 ig.Emit (OpCodes.Conv_I);
2662                                 right.Emit (ec);
2663                                 if (size != 1){
2664                                         if (size == 0)
2665                                                 ig.Emit (OpCodes.Sizeof, op_type);
2666                                         else
2667                                                 IntLiteral.EmitInt (ig, size);
2668                                         ig.Emit (OpCodes.Mul);
2669                                 }
2670                                 if (is_add)
2671                                         ig.Emit (OpCodes.Add);
2672                                 else
2673                                         ig.Emit (OpCodes.Sub);
2674                         }
2675                 }
2676         }
2677
2678         /// <summary>
2679         ///   Implements the ternary conditional operator (?:)
2680         /// </summary>
2681         public class Conditional : Expression {
2682                 Expression expr, trueExpr, falseExpr;
2683
2684                 public Conditional (Expression expr, Expression trueExpr, Expression falseExpr, Location l)
2685                 {
2686                         this.expr = expr;
2687                         this.trueExpr = trueExpr;
2688                         this.falseExpr = falseExpr;
2689                         this.loc = l;
2690                 }
2691
2692                 public Expression Expr {
2693                         get {
2694                                 return expr;
2695                         }
2696                 }
2697
2698                 public Expression TrueExpr {
2699                         get {
2700                                 return trueExpr;
2701                         }
2702                 }
2703
2704                 public Expression FalseExpr {
2705                         get {
2706                                 return falseExpr;
2707                         }
2708                 }
2709
2710                 public override Expression DoResolve (EmitContext ec)
2711                 {
2712                         expr = expr.Resolve (ec);
2713
2714                         if (expr == null)
2715                                 return null;
2716
2717                         if (expr.Type != TypeManager.bool_type)
2718                                 expr = Expression.ConvertImplicitRequired (
2719                                         ec, expr, TypeManager.bool_type, loc);
2720
2721                         trueExpr = trueExpr.Resolve (ec);
2722                         falseExpr = falseExpr.Resolve (ec);
2723
2724                         if (trueExpr == null || falseExpr == null)
2725                                 return null;
2726
2727                         eclass = ExprClass.Value;
2728                         if (trueExpr.Type == falseExpr.Type)
2729                                 type = trueExpr.Type;
2730                         else {
2731                                 Expression conv;
2732                                 Type true_type = trueExpr.Type;
2733                                 Type false_type = falseExpr.Type;
2734
2735                                 if (trueExpr is NullLiteral){
2736                                         type = false_type;
2737                                         return this;
2738                                 } else if (falseExpr is NullLiteral){
2739                                         type = true_type;
2740                                         return this;
2741                                 }
2742
2743                                 //
2744                                 // First, if an implicit conversion exists from trueExpr
2745                                 // to falseExpr, then the result type is of type falseExpr.Type
2746                                 //
2747                                 conv = ConvertImplicit (ec, trueExpr, false_type, loc);
2748                                 if (conv != null){
2749                                         //
2750                                         // Check if both can convert implicitl to each other's type
2751                                         //
2752                                         if (ConvertImplicit (ec, falseExpr, true_type, loc) != null){
2753                                                 Error (172,
2754                                                        "Can not compute type of conditional expression " +
2755                                                        "as '" + TypeManager.MonoBASIC_Name (trueExpr.Type) +
2756                                                        "' and '" + TypeManager.MonoBASIC_Name (falseExpr.Type) +
2757                                                        "' convert implicitly to each other");
2758                                                 return null;
2759                                         }
2760                                         type = false_type;
2761                                         trueExpr = conv;
2762                                 } else if ((conv = ConvertImplicit(ec, falseExpr, true_type,loc))!= null){
2763                                         type = true_type;
2764                                         falseExpr = conv;
2765                                 } else {
2766                                         Error (173, "The type of the conditional expression can " +
2767                                                "not be computed because there is no implicit conversion" +
2768                                                " from '" + TypeManager.MonoBASIC_Name (trueExpr.Type) + "'" +
2769                                                " and '" + TypeManager.MonoBASIC_Name (falseExpr.Type) + "'");
2770                                         return null;
2771                                 }
2772                         }
2773
2774                         if (expr is BoolConstant){
2775                                 BoolConstant bc = (BoolConstant) expr;
2776
2777                                 if (bc.Value)
2778                                         return trueExpr;
2779                                 else
2780                                         return falseExpr;
2781                         }
2782
2783                         return this;
2784                 }
2785
2786                 public override void Emit (EmitContext ec)
2787                 {
2788                         ILGenerator ig = ec.ig;
2789                         Label false_target = ig.DefineLabel ();
2790                         Label end_target = ig.DefineLabel ();
2791
2792                         Statement.EmitBoolExpression (ec, expr, false_target, false);
2793                         trueExpr.Emit (ec);
2794                         ig.Emit (OpCodes.Br, end_target);
2795                         ig.MarkLabel (false_target);
2796                         falseExpr.Emit (ec);
2797                         ig.MarkLabel (end_target);
2798                 }
2799
2800         }
2801
2802         /// <summary>
2803         ///   Local variables
2804         /// </summary>
2805         public class LocalVariableReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
2806                 public readonly string Name;
2807                 public readonly Block Block;
2808                 VariableInfo variable_info;
2809                 bool is_readonly;
2810
2811                 public LocalVariableReference (Block block, string name, Location l)
2812                 {
2813                         Block = block;
2814                         Name = name;
2815                         loc = l;
2816                         eclass = ExprClass.Variable;
2817                 }
2818
2819                 // Setting 'is_readonly' to false will allow you to create a writable
2820                 // reference to a read-only variable.  This is used by foreach and using.
2821                 public LocalVariableReference (Block block, string name, Location l,
2822                                                VariableInfo variable_info, bool is_readonly)
2823                         : this (block, name, l)
2824                 {
2825                         this.variable_info = variable_info;
2826                         this.is_readonly = is_readonly;
2827                 }
2828
2829                 public VariableInfo VariableInfo {
2830                         get {
2831                                 if (variable_info == null) {
2832                                         variable_info = Block.GetVariableInfo (Name);
2833                                         is_readonly = variable_info.ReadOnly;
2834                                 }
2835                                 return variable_info;
2836                         }
2837                 }
2838
2839                 public bool IsAssigned (EmitContext ec, Location loc)
2840                 {
2841                         return VariableInfo.IsAssigned (ec, loc);
2842                 }
2843
2844                 public bool IsFieldAssigned (EmitContext ec, string name, Location loc)
2845                 {
2846                         return VariableInfo.IsFieldAssigned (ec, name, loc);
2847                 }
2848
2849                 public void SetAssigned (EmitContext ec)
2850                 {
2851                         VariableInfo.SetAssigned (ec);
2852                 }
2853
2854                 public void SetFieldAssigned (EmitContext ec, string name)
2855                 {
2856                         VariableInfo.SetFieldAssigned (ec, name);
2857                 }
2858
2859                 public bool IsReadOnly {
2860                         get {
2861                                 if (variable_info == null) {
2862                                         variable_info = Block.GetVariableInfo (Name);
2863                                         is_readonly = variable_info.ReadOnly;
2864                                 }
2865                                 return is_readonly;
2866                         }
2867                 }
2868
2869                 public override Expression DoResolve (EmitContext ec)
2870                 {
2871                         VariableInfo vi = VariableInfo;
2872
2873                         if (Block.IsConstant (Name)) {
2874                                 Expression e = Block.GetConstantExpression (Name);
2875
2876                                 vi.Used = true;
2877                                 return e;
2878                         }
2879
2880                         if (ec.DoFlowAnalysis && !IsAssigned (ec, loc))
2881                                 return null;
2882
2883                         type = vi.VariableType;
2884                         return this;
2885                 }
2886
2887                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
2888                 {
2889                         VariableInfo vi = VariableInfo;
2890
2891                         if (ec.DoFlowAnalysis)
2892                                 ec.SetVariableAssigned (vi);
2893
2894                         Expression e = DoResolve (ec);
2895
2896                         if (e == null)
2897                                 return null;
2898
2899                         if (is_readonly){
2900                                 Error (1604, "cannot assign to '" + Name + "' because it is readonly");
2901                                 return null;
2902                         }
2903
2904                         return this;
2905                 }
2906
2907                 public override void Emit (EmitContext ec)
2908                 {
2909                         VariableInfo vi = VariableInfo;
2910                         ILGenerator ig = ec.ig;
2911
2912                         ig.Emit (OpCodes.Ldloc, vi.LocalBuilder);
2913                         vi.Used = true;
2914                 }
2915
2916                 public void EmitAssign (EmitContext ec, Expression source)
2917                 {
2918                         ILGenerator ig = ec.ig;
2919                         VariableInfo vi = VariableInfo;
2920
2921                         vi.Assigned = true;
2922
2923                         source.Emit (ec);
2924
2925                         ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
2926                 }
2927
2928                 public void AddressOf (EmitContext ec, AddressOp mode)
2929                 {
2930                         VariableInfo vi = VariableInfo;
2931
2932                         ec.ig.Emit (OpCodes.Ldloca, vi.LocalBuilder);
2933                 }
2934         }
2935
2936         /// <summary>
2937         ///   This represents a reference to a parameter in the intermediate
2938         ///   representation.
2939         /// </summary>
2940         public class ParameterReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
2941                 Parameters pars;
2942                 String name;
2943                 int idx;
2944                 public Parameter.Modifier mod;
2945                 public bool is_ref, is_out;
2946
2947                 public ParameterReference (Parameters pars, int idx, string name, Location loc)
2948                 {
2949                         this.pars = pars;
2950                         this.idx  = idx;
2951                         this.name = name;
2952                         this.loc = loc;
2953                         eclass = ExprClass.Variable;
2954                 }
2955
2956                 public bool IsAssigned (EmitContext ec, Location loc)
2957                 {
2958                         if (!is_out || !ec.DoFlowAnalysis)
2959                                 return true;
2960
2961                         if (!ec.CurrentBranching.IsParameterAssigned (idx)) {
2962                                 Report.Error (165, loc,
2963                                               "Use of unassigned local variable '" + name + "'");
2964                                 return false;
2965                         }
2966
2967                         return true;
2968                 }
2969
2970                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
2971                 {
2972                         if (!is_out || !ec.DoFlowAnalysis)
2973                                 return true;
2974
2975                         if (ec.CurrentBranching.IsParameterAssigned (idx))
2976                                 return true;
2977
2978                         if (!ec.CurrentBranching.IsParameterAssigned (idx, field_name)) {
2979                                 Report.Error (170, loc,
2980                                               "Use of possibly unassigned field '" + field_name + "'");
2981                                 return false;
2982                         }
2983
2984                         return true;
2985                 }
2986
2987                 public void SetAssigned (EmitContext ec)
2988                 {
2989                         if (is_out && ec.DoFlowAnalysis)
2990                                 ec.CurrentBranching.SetParameterAssigned (idx);
2991                 }
2992
2993                 public void SetFieldAssigned (EmitContext ec, string field_name)
2994                 {
2995                         if (is_out && ec.DoFlowAnalysis)
2996                                 ec.CurrentBranching.SetParameterAssigned (idx, field_name);
2997                 }
2998
2999                 //
3000                 // Notice that for ref/out parameters, the type exposed is not the
3001                 // same type exposed externally.
3002                 //
3003                 // for "ref int a":
3004                 //   externally we expose "int&"
3005                 //   here we expose       "int".
3006                 //
3007                 // We record this in "is_ref".  This means that the type system can treat
3008                 // the type as it is expected, but when we generate the code, we generate
3009                 // the alternate kind of code.
3010                 //
3011                 public override Expression DoResolve (EmitContext ec)
3012                 {
3013                         type = pars.GetParameterInfo (ec.DeclSpace, idx, out mod);
3014                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3015                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3016                         eclass = ExprClass.Variable;
3017
3018                         if (is_out && ec.DoFlowAnalysis && !IsAssigned (ec, loc))
3019                                 return null;
3020
3021                         return this;
3022                 }
3023
3024                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3025                 {
3026                         type = pars.GetParameterInfo (ec.DeclSpace, idx, out mod);
3027                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3028                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3029                         eclass = ExprClass.Variable;
3030
3031                         if (is_out && ec.DoFlowAnalysis)
3032                                 ec.SetParameterAssigned (idx);
3033
3034                         return this;
3035                 }
3036
3037                 static void EmitLdArg (ILGenerator ig, int x)
3038                 {
3039                         if (x <= 255){
3040                                 switch (x){
3041                                 case 0: ig.Emit (OpCodes.Ldarg_0); break;
3042                                 case 1: ig.Emit (OpCodes.Ldarg_1); break;
3043                                 case 2: ig.Emit (OpCodes.Ldarg_2); break;
3044                                 case 3: ig.Emit (OpCodes.Ldarg_3); break;
3045                                 default: ig.Emit (OpCodes.Ldarg_S, (byte) x); break;
3046                                 }
3047                         } else
3048                                 ig.Emit (OpCodes.Ldarg, x);
3049                 }
3050
3051                 //
3052                 // This method is used by parameters that are references, that are
3053                 // being passed as references:  we only want to pass the pointer (that
3054                 // is already stored in the parameter, not the address of the pointer,
3055                 // and not the value of the variable).
3056                 //
3057                 public void EmitLoad (EmitContext ec)
3058                 {
3059                         ILGenerator ig = ec.ig;
3060                         int arg_idx = idx;
3061
3062                         if (!ec.IsStatic)
3063                                 arg_idx++;
3064
3065                         EmitLdArg (ig, arg_idx);
3066                 }
3067
3068                 public override void Emit (EmitContext ec)
3069                 {
3070                         ILGenerator ig = ec.ig;
3071                         int arg_idx = idx;
3072
3073                         if (!ec.IsStatic)
3074                                 arg_idx++;
3075
3076                         EmitLdArg (ig, arg_idx);
3077
3078                         if (!is_ref)
3079                                 return;
3080
3081                         //
3082                         // If we are a reference, we loaded on the stack a pointer
3083                         // Now lets load the real value
3084                         //
3085                         LoadFromPtr (ig, type);
3086                 }
3087
3088                 public void EmitAssign (EmitContext ec, Expression source)
3089                 {
3090                         ILGenerator ig = ec.ig;
3091                         int arg_idx = idx;
3092
3093                         if (!ec.IsStatic)
3094                                 arg_idx++;
3095
3096                         if (is_ref)
3097                                 EmitLdArg (ig, arg_idx);
3098
3099                         source.Emit (ec);
3100
3101                         if (is_ref)
3102                                 StoreFromPtr (ig, type);
3103                         else {
3104                                 if (arg_idx <= 255)
3105                                         ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
3106                                 else
3107                                         ig.Emit (OpCodes.Starg, arg_idx);
3108                         }
3109                 }
3110
3111                 public void AddressOf (EmitContext ec, AddressOp mode)
3112                 {
3113                         int arg_idx = idx;
3114
3115                         if (!ec.IsStatic)
3116                                 arg_idx++;
3117
3118                         if (is_ref){
3119                                 if (arg_idx <= 255)
3120                                         ec.ig.Emit (OpCodes.Ldarg_S, (byte) arg_idx);
3121                                 else
3122                                         ec.ig.Emit (OpCodes.Ldarg, arg_idx);
3123                         } else {
3124                                 if (arg_idx <= 255)
3125                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
3126                                 else
3127                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
3128                         }
3129                 }
3130         }
3131
3132
3133         /// <summary>
3134         ///   Invocation of methods or delegates.
3135         /// </summary>
3136         public class Invocation : ExpressionStatement {
3137                 public ArrayList Arguments;
3138
3139                 public Expression expr;
3140                 MethodBase method = null;
3141                 bool is_base;
3142                 bool is_left_hand; // Needed for late bound calls
3143                 static Hashtable method_parameter_cache;
3144                 static MemberFilter CompareName;
3145
3146                 static Invocation ()
3147                 {
3148                         method_parameter_cache = new PtrHashtable ();
3149                 }
3150
3151                 //
3152                 // arguments is an ArrayList, but we do not want to typecast,
3153                 // as it might be null.
3154                 //
3155                 // FIXME: only allow expr to be a method invocation or a
3156                 // delegate invocation (7.5.5)
3157                 //
3158                 public Invocation (Expression expr, ArrayList arguments, Location l)
3159                 {
3160                         this.expr = expr;
3161                         Arguments = arguments;
3162                         loc = l;
3163                         CompareName = new MemberFilter (compare_name_filter);
3164                 }
3165
3166                 public Expression Expr {
3167                         get {
3168                                 return expr;
3169                         }
3170                 }
3171
3172                 /// <summary>
3173                 ///   Returns the Parameters (a ParameterData interface) for the
3174                 ///   Method 'mb'
3175                 /// </summary>
3176                 public static ParameterData GetParameterData (MethodBase mb)
3177                 {
3178                         object pd = method_parameter_cache [mb];
3179                         object ip;
3180
3181                         if (pd != null)
3182                                 return (ParameterData) pd;
3183
3184
3185                         ip = TypeManager.LookupParametersByBuilder (mb);
3186                         if (ip != null){
3187                                 method_parameter_cache [mb] = ip;
3188
3189                                 return (ParameterData) ip;
3190                         } else {
3191                                 ParameterInfo [] pi = mb.GetParameters ();
3192                                 ReflectionParameters rp = new ReflectionParameters (pi);
3193                                 method_parameter_cache [mb] = rp;
3194
3195                                 return (ParameterData) rp;
3196                         }
3197                 }
3198
3199                 /// <summary>
3200                 ///  Determines "better conversion" as specified in 7.4.2.3
3201                 ///  Returns : 1 if a->p is better
3202                 ///            0 if a->q or neither is better
3203                 /// </summary>
3204                 static int BetterConversion (EmitContext ec, Argument a, Type p, Type q, Location loc)
3205                 {
3206                         Type argument_type = a.Type;
3207                         Expression argument_expr = a.Expr;
3208
3209                         if (argument_type == null)
3210                                 throw new Exception ("Expression of type " + a.Expr + " does not resolve its type");
3211
3212                         //
3213                         // This is a special case since csc behaves this way. I can't find
3214                         // it anywhere in the spec but oh well ...
3215                         //
3216                         if (argument_expr is NullLiteral && p == TypeManager.string_type && q == TypeManager.object_type)
3217                                 return 1;
3218                         else if (argument_expr is NullLiteral && p == TypeManager.object_type && q == TypeManager.string_type)
3219                                 return 0;
3220
3221                         if (p == q)
3222                                 return 0;
3223
3224                         if (argument_type == p)
3225                                 return 1;
3226
3227                         if (argument_type == q)
3228                                 return 0;
3229
3230                         //
3231                         // Now probe whether an implicit constant expression conversion
3232                         // can be used.
3233                         //
3234                         // An implicit constant expression conversion permits the following
3235                         // conversions:
3236                         //
3237                         //    * A constant-expression of type 'int' can be converted to type
3238                         //      sbyte, byute, short, ushort, uint, ulong provided the value of
3239                         //      of the expression is withing the range of the destination type.
3240                         //
3241                         //    * A constant-expression of type long can be converted to type
3242                         //      ulong, provided the value of the constant expression is not negative
3243                         //
3244                         // FIXME: Note that this assumes that constant folding has
3245                         // taken place.  We dont do constant folding yet.
3246                         //
3247
3248                         if (argument_expr is IntConstant){
3249                                 IntConstant ei = (IntConstant) argument_expr;
3250                                 int value = ei.Value;
3251
3252                                 if (p == TypeManager.sbyte_type){
3253                                         if (value >= SByte.MinValue && value <= SByte.MaxValue)
3254                                                 return 1;
3255                                 } else if (p == TypeManager.byte_type){
3256                                         if (Byte.MinValue >= 0 && value <= Byte.MaxValue)
3257                                                 return 1;
3258                                 } else if (p == TypeManager.short_type){
3259                                         if (value >= Int16.MinValue && value <= Int16.MaxValue)
3260                                                 return 1;
3261                                 } else if (p == TypeManager.ushort_type){
3262                                         if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
3263                                                 return 1;
3264                                 } else if (p == TypeManager.uint32_type){
3265                                         //
3266                                         // we can optimize this case: a positive int32
3267                                         // always fits on a uint32
3268                                         //
3269                                         if (value >= 0)
3270                                                 return 1;
3271                                 } else if (p == TypeManager.uint64_type){
3272                                         //
3273                                         // we can optimize this case: a positive int32
3274                                         // always fits on a uint64
3275                                         //
3276                                         if (value >= 0)
3277                                                 return 1;
3278                                 }
3279                         } else if (argument_type == TypeManager.int64_type && argument_expr is LongConstant){
3280                                 LongConstant lc = (LongConstant) argument_expr;
3281
3282                                 if (p == TypeManager.uint64_type){
3283                                         if (lc.Value > 0)
3284                                                 return 1;
3285                                 }
3286                         }
3287
3288                         if (q == null) {
3289                                 Expression tmp = ConvertImplicit (ec, argument_expr, p, loc);
3290
3291                                 if (tmp != null)
3292                                         return 1;
3293                                 else
3294                                         return 0;
3295                         }
3296
3297                         Expression p_tmp = new EmptyExpression (p);
3298                         Expression q_tmp = new EmptyExpression (q);
3299
3300                         if (StandardConversionExists (p_tmp, q) == true &&
3301                             StandardConversionExists (q_tmp, p) == false)
3302                                 return 1;
3303
3304                         if (p == TypeManager.sbyte_type)
3305                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3306                                     q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3307                                         return 1;
3308
3309                         if (p == TypeManager.short_type)
3310                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3311                                     q == TypeManager.uint64_type)
3312                                         return 1;
3313
3314                         if (p == TypeManager.int32_type)
3315                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3316                                         return 1;
3317
3318                         if (p == TypeManager.int64_type)
3319                                 if (q == TypeManager.uint64_type)
3320                                         return 1;
3321
3322                         return 0;
3323                 }
3324
3325                 /// <summary>
3326                 ///  Determines "Better function"
3327                 /// </summary>
3328                 /// <remarks>
3329                 ///    and returns an integer indicating :
3330                 ///    0 if candidate ain't better
3331                 ///    1 if candidate is better than the current best match
3332                 /// </remarks>
3333                 static int BetterFunction (EmitContext ec, ArrayList args,
3334                                            MethodBase candidate, MethodBase best,
3335                                            bool expanded_form, Location loc)
3336                 {
3337                         ParameterData candidate_pd = GetParameterData (candidate);
3338                         ParameterData best_pd;
3339                         int argument_count;
3340
3341                         if (args == null)
3342                                 argument_count = 0;
3343                         else
3344                                 argument_count = args.Count;
3345
3346                         int cand_count = candidate_pd.Count;
3347
3348                         if (cand_count == 0 && argument_count == 0)
3349                                 return 1;
3350
3351                         if (candidate_pd.ParameterModifier (cand_count - 1) != Parameter.Modifier.PARAMS)
3352                                 if (cand_count != argument_count)
3353                                         return 0;
3354
3355                         if (best == null) {
3356                                 int x = 0;
3357
3358                                 if (argument_count == 0 && cand_count == 1 &&
3359                                     candidate_pd.ParameterModifier (cand_count - 1) == Parameter.Modifier.PARAMS)
3360                                         return 1;
3361
3362                                 for (int j = argument_count; j > 0;) {
3363                                         j--;
3364
3365                                         Argument a = (Argument) args [j];
3366                                         Type t = candidate_pd.ParameterType (j);
3367
3368                                         if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3369                                                 if (expanded_form)
3370                                                         t = t.GetElementType ();
3371
3372                                         x = BetterConversion (ec, a, t, null, loc);
3373
3374                                         if (x <= 0)
3375                                                 break;
3376                                 }
3377
3378                                 if (x > 0)
3379                                         return 1;
3380                                 else
3381                                         return 0;
3382                         }
3383
3384                         best_pd = GetParameterData (best);
3385
3386                         int rating1 = 0, rating2 = 0;
3387
3388                         for (int j = 0; j < argument_count; ++j) {
3389                                 int x, y;
3390
3391                                 Argument a = (Argument) args [j];
3392
3393                                 Type ct = candidate_pd.ParameterType (j);
3394                                 Type bt = best_pd.ParameterType (j);
3395
3396                                 if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3397                                         if (expanded_form)
3398                                                 ct = ct.GetElementType ();
3399
3400                                 if (best_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3401                                         if (expanded_form)
3402                                                 bt = bt.GetElementType ();
3403
3404                                 x = BetterConversion (ec, a, ct, bt, loc);
3405                                 y = BetterConversion (ec, a, bt, ct, loc);
3406
3407                                 if (x < y)
3408                                         return 0;
3409
3410                                 rating1 += x;
3411                                 rating2 += y;
3412                         }
3413
3414                         if (rating1 > rating2)
3415                                 return 1;
3416                         else
3417                                 return 0;
3418                 }
3419
3420                 public static string FullMethodDesc (MethodBase mb)
3421                 {
3422                         string ret_type = "";
3423
3424                         if (mb is MethodInfo)
3425                                 ret_type = TypeManager.MonoBASIC_Name (((MethodInfo) mb).ReturnType) + " ";
3426
3427                         StringBuilder sb = new StringBuilder (ret_type + mb.Name);
3428                         ParameterData pd = GetParameterData (mb);
3429
3430                         int count = pd.Count;
3431                         sb.Append (" (");
3432
3433                         for (int i = count; i > 0; ) {
3434                                 i--;
3435
3436                                 sb.Append (pd.ParameterDesc (count - i - 1));
3437                                 if (i != 0)
3438                                         sb.Append (", ");
3439                         }
3440
3441                         sb.Append (")");
3442                         return sb.ToString ();
3443                 }
3444
3445                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3446                 {
3447                         MemberInfo [] miset;
3448                         MethodGroupExpr union;
3449
3450                         if (mg1 == null){
3451                                 if (mg2 == null)
3452                                         return null;
3453                                 return (MethodGroupExpr) mg2;
3454                         } else {
3455                                 if (mg2 == null)
3456                                         return (MethodGroupExpr) mg1;
3457                         }
3458
3459                         MethodGroupExpr left_set = null, right_set = null;
3460                         int length1 = 0, length2 = 0;
3461
3462                         left_set = (MethodGroupExpr) mg1;
3463                         length1 = left_set.Methods.Length;
3464
3465                         right_set = (MethodGroupExpr) mg2;
3466                         length2 = right_set.Methods.Length;
3467
3468                         ArrayList common = new ArrayList ();
3469
3470                         foreach (MethodBase l in left_set.Methods){
3471                                 foreach (MethodBase r in right_set.Methods){
3472                                         if (l != r)
3473                                                 continue;
3474                                         common.Add (r);
3475                                         break;
3476                                 }
3477                         }
3478
3479                         miset = new MemberInfo [length1 + length2 - common.Count];
3480                         left_set.Methods.CopyTo (miset, 0);
3481
3482                         int k = length1;
3483
3484                         foreach (MemberInfo mi in right_set.Methods){
3485                                 if (!common.Contains (mi))
3486                                         miset [k++] = mi;
3487                         }
3488
3489                         union = new MethodGroupExpr (miset, loc);
3490
3491                         return union;
3492                 }
3493
3494                 /// <summary>
3495                 ///  Determines is the candidate method, if a params method, is applicable
3496                 ///  in its expanded form to the given set of arguments
3497                 /// </summary>
3498                 static bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments, MethodBase candidate)
3499                 {
3500                         int arg_count;
3501
3502                         if (arguments == null)
3503                                 arg_count = 0;
3504                         else
3505                                 arg_count = arguments.Count;
3506
3507                         ParameterData pd = GetParameterData (candidate);
3508
3509                         int pd_count = pd.Count;
3510
3511                         if (pd_count == 0)
3512                                 return false;
3513
3514                         if (pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS)
3515                                 return false;
3516
3517                         if (pd_count - 1 > arg_count)
3518                                 return false;
3519
3520                         if (pd_count == 1 && arg_count == 0)
3521                                 return true;
3522
3523                         //
3524                         // If we have come this far, the case which remains is when the number of parameters
3525                         // is less than or equal to the argument count.
3526                         //
3527                         for (int i = 0; i < pd_count - 1; ++i) {
3528
3529                                 Argument a = (Argument) arguments [i];
3530
3531                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3532                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3533                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3534                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3535
3536                                 if (a_mod == p_mod) {
3537
3538                                         if (a_mod == Parameter.Modifier.NONE)
3539                                                 if (!ImplicitConversionExists (ec, a.Expr, pd.ParameterType (i)))
3540                                                         return false;
3541
3542                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3543                                                 Type pt = pd.ParameterType (i);
3544
3545                                                 if (!pt.IsByRef)
3546                                                         pt = TypeManager.LookupType (pt.FullName + "&");
3547
3548                                                 if (pt != a.Type)
3549                                                         return false;
3550                                         }
3551                                 } else
3552                                         return false;
3553
3554                         }
3555
3556                         Type element_type = pd.ParameterType (pd_count - 1).GetElementType ();
3557
3558                         for (int i = pd_count - 1; i < arg_count; i++) {
3559                                 Argument a = (Argument) arguments [i];
3560
3561                                 if (!StandardConversionExists (a.Expr, element_type))
3562                                         return false;
3563                         }
3564
3565                         return true;
3566                 }
3567
3568                 static bool CheckParameterAgainstArgument (EmitContext ec, ParameterData pd, int i, Argument a, Type ptype)
3569                 {
3570                         Parameter.Modifier a_mod = a.GetParameterModifier () &
3571                                 ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3572                         Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3573                                 ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3574
3575                         if (a_mod == p_mod || (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
3576                                 if (a_mod == Parameter.Modifier.NONE)
3577                                         if (! (ImplicitConversionExists (ec, a.Expr, ptype) || RuntimeConversionExists (ec, a.Expr, ptype)) )
3578                                                 return false;
3579
3580                                 if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3581                                         Type pt = pd.ParameterType (i);
3582
3583                                         if (!pt.IsByRef)
3584                                                 pt = TypeManager.LookupType (pt.FullName + "&");
3585
3586                                         if (pt != a.Type)
3587                                                 return false;
3588                                 }
3589                         } else
3590                                 return false;
3591                         return true;
3592                 }
3593
3594                 /// <summary>
3595                 ///  Determines if the candidate method is applicable (section 14.4.2.1)
3596                 ///  to the given set of arguments
3597                 /// </summary>
3598                 static bool IsApplicable (EmitContext ec, ref ArrayList arguments, MethodBase candidate)
3599                 {
3600                         int arg_count, ps_count, po_count;
3601                         Type param_type;
3602
3603                         if (arguments == null)
3604                                 arg_count = 0;
3605                         else
3606                                 arg_count = arguments.Count;
3607
3608                         ParameterData pd = GetParameterData (candidate);
3609                         Parameters ps = GetFullParameters (candidate);
3610
3611                         if (ps == null) {
3612                                 ps_count = 0;
3613                                 po_count = 0;
3614                         }
3615                         else
3616                         {
3617                                 ps_count = ps.CountStandardParams();
3618                                 po_count = ps.CountOptionalParams();
3619                         }
3620                         int pd_count = pd.Count;
3621
3622                         // Validate argument count
3623                         if (po_count == 0) {
3624                                 if (arg_count != pd.Count)
3625                                         return false;
3626                         }
3627                         else
3628                         {
3629                                 if ((arg_count < ps_count) || (arg_count > pd_count))
3630                                         return false;
3631                         }
3632
3633                         if (arg_count > 0) {
3634                                 for (int i = arg_count; i > 0 ; ) {
3635                                         i--;
3636
3637                                         Argument a = (Argument) arguments [i];
3638                                         if (a.ArgType == Argument.AType.NoArg)
3639                                         {
3640                                                 Parameter p = (Parameter) ps.FixedParameters[i];
3641                                                 a = new Argument (p.ParameterInitializer, Argument.AType.Expression);
3642                                                 param_type = p.ParameterInitializer.Type;
3643                                         }
3644                                         else
3645                                         {
3646                                                 param_type = pd.ParameterType (i);
3647                                                 if (ps != null) {
3648                                                         Parameter p = (Parameter) ps.FixedParameters[i];
3649
3650                                                         if ((p.ModFlags & Parameter.Modifier.REF) != 0)
3651                                                         {
3652                                                                 a = new Argument (a.Expr, Argument.AType.Ref);
3653                                                                 if (!a.Resolve(ec,Location.Null))
3654                                                                         return false;
3655                                                         }
3656                                                 }
3657                                         }
3658
3659                                         if (!CheckParameterAgainstArgument (ec, pd, i, a, param_type))
3660                                                 return (false);
3661                                 }
3662                         }
3663                         else
3664                         {
3665                                 // If we have no arguments AND the first parameter is optional
3666                                 // we must check for a candidate (the loop above wouldn't)
3667                                 if (po_count > 0) {
3668                                         ArrayList arglist = new ArrayList();
3669
3670                                         // Since we got so far, there's no need to check if
3671                                         // arguments are optional; we simply retrieve
3672                                         // parameter default values and build a brand-new
3673                                         // argument list.
3674
3675                                         for (int i = 0; i < ps.FixedParameters.Length; i++) {
3676                                                 Parameter p = ps.FixedParameters[i];
3677                                                 Argument a = new Argument (p.ParameterInitializer, Argument.AType.Expression);
3678                                                 a.Resolve(ec, Location.Null);
3679                                                 arglist.Add (a);
3680                                         }
3681                                         arguments = arglist;
3682                                         return true;
3683                                 }
3684                         }
3685                         // We've found a candidate, so we exchange the dummy NoArg arguments
3686                         // with new arguments containing the default value for that parameter
3687                         ArrayList newarglist = new ArrayList();
3688                         for (int i = 0; i < arg_count; i++) {
3689                                 Argument a = (Argument) arguments [i];
3690                                 Parameter p = null;
3691
3692                                 if (ps != null)
3693                                         p = (Parameter) ps.FixedParameters[i];
3694
3695                                 if (a.ArgType == Argument.AType.NoArg){
3696                                         a = new Argument (p.ParameterInitializer, Argument.AType.Expression);
3697                                         a.Resolve(ec, Location.Null);
3698                                 }
3699
3700                                 if ((p != null) && ((p.ModFlags & Parameter.Modifier.REF) != 0))
3701                                 {
3702                                         a.ArgType = Argument.AType.Ref;
3703                                         a.Resolve(ec, Location.Null);
3704                                 }
3705                                 newarglist.Add(a);
3706                                 int n = pd_count - arg_count;
3707                                 if (n > 0)
3708                                 {
3709                                         for (int x = 0; x < n; x++)
3710                                         {
3711                                                 Parameter op = (Parameter) ps.FixedParameters[x + arg_count];
3712                                                 Argument b = new Argument (op.ParameterInitializer, Argument.AType.Expression);
3713                                                 b.Resolve(ec, Location.Null);
3714                                                 newarglist.Add (b);
3715                                         }
3716                                 }
3717                         }
3718                         arguments = newarglist;
3719                         return true;
3720                 }
3721
3722                 static bool compare_name_filter (MemberInfo m, object filterCriteria)
3723                 {
3724                         return (m.Name == ((string) filterCriteria));
3725                 }
3726
3727                 static Parameters GetFullParameters (MethodBase mb)
3728                 {
3729                         TypeContainer tc = TypeManager.LookupTypeContainer (mb.DeclaringType);
3730                         InternalParameters ip = TypeManager.LookupParametersByBuilder(mb);
3731
3732                         return (ip != null) ? ip.Parameters : null;
3733                 }
3734
3735                 // We need an overload for OverloadResolve because Invocation.DoResolve
3736                 // must pass Arguments by reference, since a later call to IsApplicable
3737                 // can change the argument list if optional parameters are defined
3738                 // in the method declaration
3739                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
3740                                                           ArrayList Arguments, Location loc)
3741                 {
3742                         ArrayList a = Arguments;
3743                         return OverloadResolve (ec, me, ref a, loc);
3744                 }
3745
3746                 /// <summary>
3747                 ///   Find the Applicable Function Members (7.4.2.1)
3748                 ///
3749                 ///   me: Method Group expression with the members to select.
3750                 ///       it might contain constructors or methods (or anything
3751                 ///       that maps to a method).
3752                 ///
3753                 ///   Arguments: ArrayList containing resolved Argument objects.
3754                 ///
3755                 ///   loc: The location if we want an error to be reported, or a Null
3756                 ///        location for "probing" purposes.
3757                 ///
3758                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3759                 ///            that is the best match of me on Arguments.
3760                 ///
3761                 /// </summary>
3762                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
3763                                                           ref ArrayList Arguments, Location loc)
3764                 {
3765                         ArrayList afm = new ArrayList ();
3766                         MethodBase method = null;
3767                         Type current_type = null;
3768                         int argument_count;
3769                         ArrayList candidates = new ArrayList ();
3770
3771                         foreach (MethodBase candidate in me.Methods){
3772                                 int x;
3773
3774                                 // If we're going one level higher in the class hierarchy, abort if
3775                                 // we already found an applicable method.
3776                                 if (candidate.DeclaringType != current_type) {
3777                                         current_type = candidate.DeclaringType;
3778                                         if (method != null)
3779                                                 break;
3780                                 }
3781
3782                                 // Check if candidate is applicable (section 14.4.2.1)
3783                                 if (!IsApplicable (ec, ref Arguments, candidate))
3784                                         continue;
3785
3786                                 candidates.Add (candidate);
3787                                 x = BetterFunction (ec, Arguments, candidate, method, false, loc);
3788
3789                                 if (x == 0)
3790                                         continue;
3791
3792                                 method = candidate;
3793                         }
3794
3795                         if (Arguments == null)
3796                                 argument_count = 0;
3797                         else
3798                                 argument_count = Arguments.Count;
3799
3800
3801                         //
3802                         // Now we see if we can find params functions, applicable in their expanded form
3803                         // since if they were applicable in their normal form, they would have been selected
3804                         // above anyways
3805                         //
3806                         bool chose_params_expanded = false;
3807
3808                         if (method == null) {
3809                                 candidates = new ArrayList ();
3810                                 foreach (MethodBase candidate in me.Methods){
3811                                         if (!IsParamsMethodApplicable (ec, Arguments, candidate))
3812                                                 continue;
3813
3814                                         candidates.Add (candidate);
3815
3816                                         int x = BetterFunction (ec, Arguments, candidate, method, true, loc);
3817                                         if (x == 0)
3818                                                 continue;
3819
3820                                         method = candidate;
3821                                         chose_params_expanded = true;
3822                                 }
3823                         }
3824
3825                         if (method == null) {
3826                                 //
3827                                 // Okay so we have failed to find anything so we
3828                                 // return by providing info about the closest match
3829                                 //
3830                                 for (int i = 0; i < me.Methods.Length; ++i) {
3831
3832                                         MethodBase c = (MethodBase) me.Methods [i];
3833                                         ParameterData pd = GetParameterData (c);
3834
3835                                         if (pd.Count != argument_count)
3836                                                 continue;
3837
3838                                         VerifyArgumentsCompat (ec, Arguments, argument_count, c, false,
3839                                                                null, loc);
3840                                 }
3841
3842                                 return null;
3843                         }
3844
3845                         //
3846                         // Now check that there are no ambiguities i.e the selected method
3847                         // should be better than all the others
3848                         //
3849
3850                         foreach (MethodBase candidate in candidates){
3851                                 if (candidate == method)
3852                                         continue;
3853
3854                                 //
3855                                 // If a normal method is applicable in the sense that it has the same
3856                                 // number of arguments, then the expanded params method is never applicable
3857                                 // so we debar the params method.
3858                                 //
3859                                 if (IsParamsMethodApplicable (ec, Arguments, candidate) &&
3860                                     IsApplicable (ec, ref Arguments, method))
3861                                         continue;
3862
3863                                 int x = BetterFunction (ec, Arguments, method, candidate,
3864                                                         chose_params_expanded, loc);
3865
3866                                 if (x != 1) {
3867                                         Report.Error (
3868                                                 121, loc,
3869                                                 "Ambiguous call when selecting function due to implicit casts");
3870                                         return null;
3871                                 }
3872                         }
3873
3874                         //
3875                         // And now check if the arguments are all compatible, perform conversions
3876                         // if necessary etc. and return if everything is all right
3877                         //
3878                         if (VerifyArgumentsCompat (ec, Arguments, argument_count, method,
3879                                                    chose_params_expanded, null, loc))
3880                                 return method;
3881                         else
3882                                 return null;
3883                 }
3884
3885                 public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
3886                         int argument_count,
3887                         MethodBase method,
3888                         bool chose_params_expanded,
3889                         Type delegate_type,
3890                         Location loc)
3891                 {
3892                         return (VerifyArgumentsCompat (ec, Arguments, argument_count,
3893                                 method, chose_params_expanded, delegate_type, loc, null));
3894                 }
3895
3896                 public static bool VerifyArgumentsCompat (EmitContext ec,
3897                                                           ArrayList Arguments,
3898                                                           int argument_count,
3899                                                           MethodBase method,
3900                                                           bool chose_params_expanded,
3901                                                           Type delegate_type,
3902                                                           Location loc,
3903                                                           string InvokingProperty)
3904                 {
3905                         ParameterData pd = GetParameterData (method);
3906                         int pd_count = pd.Count;
3907
3908                         for (int j = 0; j < argument_count; j++) {
3909                                 Argument a = (Argument) Arguments [j];
3910                                 Expression a_expr = a.Expr;
3911                                 Type parameter_type = pd.ParameterType(j);
3912
3913                                 if (parameter_type == null)
3914                                 {
3915                                         Error_WrongNumArguments(loc, (InvokingProperty == null)?((delegate_type == null)?FullMethodDesc (method):delegate_type.ToString ()):InvokingProperty, argument_count);
3916                                         return false;
3917                                 }
3918                                 if (pd.ParameterModifier (j) == Parameter.Modifier.PARAMS &&
3919                                 chose_params_expanded)
3920                                         parameter_type = TypeManager.TypeToCoreType (parameter_type.GetElementType ());
3921
3922                                 if (a.Type != parameter_type){
3923                                         Expression conv;
3924
3925                                         conv = ConvertImplicit (ec, a_expr, parameter_type, loc);
3926
3927                                         if (conv == null) {
3928                                                 if (!Location.IsNull (loc)) {
3929                                                         if (delegate_type == null)
3930                                                                 if (InvokingProperty == null)
3931                                                                         Report.Error (1502, loc,
3932                                                                                 "The best overloaded match for method '" +
3933                                                                                 FullMethodDesc (method) +
3934                                                                                 "' has some invalid arguments");
3935                                                                 else
3936                                                                         Report.Error (1502, loc,
3937                                                                                 "Property '" +
3938                                                                                 InvokingProperty +
3939                                                                                 "' has some invalid arguments");
3940                                                         else
3941                                                                 Report.Error (1594, loc,
3942                                                                               "Delegate '" + delegate_type.ToString () +
3943                                                                               "' has some invalid arguments.");
3944                                                         Report.Error (1503, loc,
3945                                                          "Argument " + (j+1) +
3946                                                          ": Cannot convert from '" + Argument.FullDesc (a)
3947                                                          + "' to '" + pd.ParameterDesc (j) + "'");
3948                                                 }
3949
3950                                                 return false;
3951                                         }
3952
3953                                         //
3954                                         // Update the argument with the implicit conversion
3955                                         //
3956                                         if (a_expr != conv)
3957                                                 a.Expr = conv;
3958                                 }
3959
3960                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3961                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3962                                 Parameter.Modifier p_mod = pd.ParameterModifier (j) &
3963                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3964
3965
3966                                 if (a_mod != p_mod &&
3967                                     pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
3968                                         if (!Location.IsNull (loc)) {
3969                                                 Report.Error (1502, loc,
3970                                                        "The best overloaded match for method '" + FullMethodDesc (method)+
3971                                                        "' has some invalid arguments");
3972                                                 Report.Error (1503, loc,
3973                                                        "Argument " + (j+1) +
3974                                                        ": Cannot convert from '" + Argument.FullDesc (a)
3975                                                        + "' to '" + pd.ParameterDesc (j) + "'");
3976                                         }
3977
3978                                         return false;
3979                                 }
3980                         }
3981
3982                         return true;
3983                 }
3984
3985                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
3986                 {
3987                         this.is_left_hand = true;
3988                         return DoResolve (ec);
3989                 }
3990
3991                 public override Expression DoResolve (EmitContext ec)
3992                 {
3993                         //
3994                         // First, resolve the expression that is used to
3995                         // trigger the invocation
3996                         //
3997                         Expression expr_to_return = null;
3998
3999                         if (expr is BaseAccess)
4000                                 is_base = true;
4001
4002                         if ((ec.ReturnType != null) && (expr.ToString() == ec.BlockName)) {
4003                                 ec.InvokingOwnOverload = true;
4004                                 expr = expr.Resolve (ec, ResolveFlags.MethodGroup);
4005                                 ec.InvokingOwnOverload = false;
4006                         }
4007                         else
4008                         {
4009                                 ec.InvokingOwnOverload = false;
4010                                 expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
4011                         }
4012                         if (expr == null)
4013                                 return null;
4014
4015                         if (expr is Invocation) {
4016                                 // FIXME Calls which return an Array are not resolved (here or in the grammar)
4017                                 expr = expr.Resolve(ec);
4018                         }
4019
4020                         if (!(expr is MethodGroupExpr))
4021                         {
4022                                 Type expr_type = expr.Type;
4023
4024                                 if (expr_type != null)
4025                                 {
4026                                         bool IsDelegate = TypeManager.IsDelegateType (expr_type);
4027                                         if (IsDelegate)
4028                                                 return (new DelegateInvocation (
4029                                                         this.expr, Arguments, loc)).Resolve (ec);
4030                                 }
4031                         }
4032
4033                         //
4034                         // Next, evaluate all the expressions in the argument list
4035                         //
4036                         if (Arguments != null)
4037                         {
4038                                 foreach (Argument a in Arguments)
4039                                 {
4040                                         if ((a.ArgType == Argument.AType.NoArg) && (!(expr is MethodGroupExpr)))
4041                                                 Report.Error (999, "This item cannot have empty arguments");
4042
4043                                         if (!a.Resolve (ec, loc))
4044                                                 return null;
4045                                 }
4046                         }
4047
4048                         if (expr is MethodGroupExpr)
4049                         {
4050                                 MethodGroupExpr mg = (MethodGroupExpr) expr;
4051                                 method = OverloadResolve (ec, mg, ref Arguments, loc);
4052
4053                                 if (method == null)
4054                                 {
4055                                         Error (-6,
4056                                                 "Could not find any applicable function for this argument list");
4057                                         return null;
4058                                 }
4059
4060                                 if ((method as MethodInfo) != null)
4061                                 {
4062                                         MethodInfo mi = method as MethodInfo;
4063                                         type = TypeManager.TypeToCoreType (mi.ReturnType);
4064                                         if (!mi.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null))
4065                                                 SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
4066                                 }
4067
4068                                 if ((method as ConstructorInfo) != null)
4069                                 {
4070                                         ConstructorInfo ci = method as ConstructorInfo;
4071                                         type = TypeManager.void_type;
4072                                         if (!ci.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null))
4073                                                 SimpleName.Error_ObjectRefRequired (ec, loc, ci.Name);
4074                                 }
4075
4076                                 if (type.IsPointer)
4077                                 {
4078                                         if (!ec.InUnsafe)
4079                                         {
4080                                                 UnsafeError (loc);
4081                                                 return null;
4082                                         }
4083                                 }
4084                                 eclass = ExprClass.Value;
4085                                 expr_to_return = this;
4086                         }
4087
4088                         if (expr is PropertyExpr)
4089                         {
4090                                 PropertyExpr pe = ((PropertyExpr) expr);
4091                                 pe.PropertyArgs = (ArrayList) Arguments.Clone();
4092                                 Arguments.Clear();
4093                                 Arguments = new ArrayList();
4094                                 MethodBase mi = pe.PropertyInfo.GetGetMethod(true);
4095
4096                                 if(VerifyArgumentsCompat (ec, pe.PropertyArgs,
4097                                         pe.PropertyArgs.Count, mi, false, null, loc, pe.Name))
4098                                 {
4099
4100                                         expr_to_return = pe.DoResolve (ec);
4101                                         expr_to_return.eclass = ExprClass.PropertyAccess;
4102                                 }
4103                                 else
4104                                 {
4105                                         throw new Exception("Error resolving Property Access expression\n" + pe.ToString());
4106                                 }
4107                         }
4108
4109                         if (expr is FieldExpr || expr is LocalVariableReference || expr is ParameterReference) {
4110                                 if (expr.Type.IsArray) {
4111                                         // If we are here, expr must be an ArrayAccess
4112                                         ArrayList idxs = new ArrayList();
4113                                         foreach (Argument a in Arguments)
4114                                         {
4115                                                 idxs.Add (a.Expr);
4116                                         }
4117                                         ElementAccess ea = new ElementAccess (expr, idxs, expr.Location);
4118                                         ArrayAccess aa = new ArrayAccess (ea, expr.Location);
4119                                         expr_to_return = aa.DoResolve(ec);
4120                                         expr_to_return.eclass = ExprClass.Variable;
4121                                 }
4122                                 else
4123                                 {
4124                                         // We can't resolve now, but we
4125                                         // have to try to access the array with a call
4126                                         // to LateIndexGet/Set in the runtime
4127                                         Expression lig_call_expr;
4128
4129                                         if (!is_left_hand)
4130                                                 lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexGet", Location.Null);
4131                                         else
4132                                                 lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexSet", Location.Null);
4133                                         Expression obj_type = Mono.MonoBASIC.Parser.DecomposeQI("System.Object", Location.Null);
4134                                         ArrayList adims = new ArrayList();
4135
4136                                         ArrayList ainit = new ArrayList();
4137                                         foreach (Argument a in Arguments)
4138                                                 ainit.Add ((Expression) a.Expr);
4139
4140                                         adims.Add ((Expression) new IntLiteral (Arguments.Count));
4141
4142                                         Expression oace = new ArrayCreation (obj_type, adims, "", ainit, Location.Null);
4143
4144                                         ArrayList args = new ArrayList();
4145                                         args.Add (new Argument(expr, Argument.AType.Expression));
4146                                         args.Add (new Argument(oace, Argument.AType.Expression));
4147                                         args.Add (new Argument(NullLiteral.Null, Argument.AType.Expression));
4148
4149                                         Expression lig_call = new Invocation (lig_call_expr, args, Location.Null);
4150                                         expr_to_return = lig_call.Resolve(ec);
4151                                         expr_to_return.eclass = ExprClass.Variable;
4152                                 }
4153                         }
4154
4155                         return expr_to_return;
4156                 }
4157
4158         static void Error_WrongNumArguments (Location loc, String name, int arg_count)
4159         {
4160             Report.Error (1501, loc, "No overload for method `" + name + "' takes `" +
4161                                       arg_count + "' arguments");
4162         }
4163
4164                 // <summary>
4165                 //   Emits the list of arguments as an array
4166                 // </summary>
4167                 static void EmitParams (EmitContext ec, int idx, ArrayList arguments)
4168                 {
4169                         ILGenerator ig = ec.ig;
4170                         int count = arguments.Count - idx;
4171                         Argument a = (Argument) arguments [idx];
4172                         Type t = a.Expr.Type;
4173                         string array_type = t.FullName + "[]";
4174                         LocalBuilder array;
4175
4176                         array = ig.DeclareLocal (TypeManager.LookupType (array_type));
4177                         IntConstant.EmitInt (ig, count);
4178                         ig.Emit (OpCodes.Newarr, TypeManager.TypeToCoreType (t));
4179                         ig.Emit (OpCodes.Stloc, array);
4180
4181                         int top = arguments.Count;
4182                         for (int j = idx; j < top; j++){
4183                                 a = (Argument) arguments [j];
4184
4185                                 ig.Emit (OpCodes.Ldloc, array);
4186                                 IntConstant.EmitInt (ig, j - idx);
4187                                 a.Emit (ec);
4188
4189                                 ArrayAccess.EmitStoreOpcode (ig, t);
4190                         }
4191                         ig.Emit (OpCodes.Ldloc, array);
4192                 }
4193
4194                 /// <summary>
4195                 ///   Emits a list of resolved Arguments that are in the arguments
4196                 ///   ArrayList.
4197                 ///
4198                 ///   The MethodBase argument might be null if the
4199                 ///   emission of the arguments is known not to contain
4200                 ///   a 'params' field (for example in constructors or other routines
4201                 ///   that keep their arguments in this structure)
4202                 /// </summary>
4203                 public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments)
4204                 {
4205                         ParameterData pd;
4206                         if (mb != null)
4207                                 pd = GetParameterData (mb);
4208                         else
4209                                 pd = null;
4210
4211                         //
4212                         // If we are calling a params method with no arguments, special case it
4213                         //
4214                         if (arguments == null){
4215                                 if (pd != null && pd.Count > 0 &&
4216                                     pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
4217                                         ILGenerator ig = ec.ig;
4218
4219                                         IntConstant.EmitInt (ig, 0);
4220                                         ig.Emit (OpCodes.Newarr, pd.ParameterType (0).GetElementType ());
4221                                 }
4222                                 return;
4223                         }
4224
4225                         int top = arguments.Count;
4226
4227                         for (int i = 0; i < top; i++){
4228                                 Argument a = (Argument) arguments [i];
4229
4230                                 if (pd != null){
4231                                         if (pd.ParameterModifier (i) == Parameter.Modifier.PARAMS){
4232                                                 //
4233                                                 // Special case if we are passing the same data as the
4234                                                 // params argument, do not put it in an array.
4235                                                 //
4236                                                 if (pd.ParameterType (i) == a.Type)
4237                                                         a.Emit (ec);
4238                                                 else
4239                                                         EmitParams (ec, i, arguments);
4240                                                 return;
4241                                         }
4242                                 }
4243
4244                                 a.Emit (ec);
4245                         }
4246
4247                         if (pd != null && pd.Count > top &&
4248                             pd.ParameterModifier (top) == Parameter.Modifier.PARAMS){
4249                                 ILGenerator ig = ec.ig;
4250
4251                                 IntConstant.EmitInt (ig, 0);
4252                                 ig.Emit (OpCodes.Newarr, pd.ParameterType (top).GetElementType ());
4253                         }
4254                 }
4255
4256                 /// <remarks>
4257                 ///   is_base tells whether we want to force the use of the 'call'
4258                 ///   opcode instead of using callvirt.  Call is required to call
4259                 ///   a specific method, while callvirt will always use the most
4260                 ///   recent method in the vtable.
4261                 ///
4262                 ///   is_static tells whether this is an invocation on a static method
4263                 ///
4264                 ///   instance_expr is an expression that represents the instance
4265                 ///   it must be non-null if is_static is false.
4266                 ///
4267                 ///   method is the method to invoke.
4268                 ///
4269                 ///   Arguments is the list of arguments to pass to the method or constructor.
4270                 /// </remarks>
4271                 public static void EmitCall (EmitContext ec, bool is_base,
4272                                              bool is_static, Expression instance_expr,
4273                                              MethodBase method, ArrayList Arguments, Location loc)
4274                 {
4275                         EmitCall (ec, is_base, is_static, instance_expr, method, Arguments, null, loc);
4276                 }
4277
4278                 public static void EmitCall (EmitContext ec, bool is_base,
4279                         bool is_static, Expression instance_expr,
4280                         MethodBase method, ArrayList Arguments, ArrayList prop_args, Location loc)
4281                 {
4282                         ILGenerator ig = ec.ig;
4283                         bool struct_call = false;
4284
4285                         Type decl_type = method.DeclaringType;
4286
4287                         if (!RootContext.StdLib)
4288                         {
4289                                 // Replace any calls to the system's System.Array type with calls to
4290                                 // the newly created one.
4291                                 if (method == TypeManager.system_int_array_get_length)
4292                                         method = TypeManager.int_array_get_length;
4293                                 else if (method == TypeManager.system_int_array_get_rank)
4294                                         method = TypeManager.int_array_get_rank;
4295                                 else if (method == TypeManager.system_object_array_clone)
4296                                         method = TypeManager.object_array_clone;
4297                                 else if (method == TypeManager.system_int_array_get_length_int)
4298                                         method = TypeManager.int_array_get_length_int;
4299                                 else if (method == TypeManager.system_int_array_get_lower_bound_int)
4300                                         method = TypeManager.int_array_get_lower_bound_int;
4301                                 else if (method == TypeManager.system_int_array_get_upper_bound_int)
4302                                         method = TypeManager.int_array_get_upper_bound_int;
4303                                 else if (method == TypeManager.system_void_array_copyto_array_int)
4304                                         method = TypeManager.void_array_copyto_array_int;
4305                         }
4306
4307                         //
4308                         // This checks the 'ConditionalAttribute' on the method, and the
4309                         // ObsoleteAttribute
4310                         //
4311                         TypeManager.MethodFlags flags = TypeManager.GetMethodFlags (method, loc);
4312                         if ((flags & TypeManager.MethodFlags.IsObsoleteError) != 0)
4313                                 return;
4314                         if ((flags & TypeManager.MethodFlags.ShouldIgnore) != 0)
4315                                 return;
4316
4317                         if (!is_static)
4318                         {
4319                                 if (decl_type.IsValueType)
4320                                         struct_call = true;
4321                                 //
4322                                 // If this is ourselves, push "this"
4323                                 //
4324                                 if (instance_expr == null)
4325                                 {
4326                                         ig.Emit (OpCodes.Ldarg_0);
4327                                 }
4328                                 else
4329                                 {
4330                                         //
4331                                         // Push the instance expression
4332                                         //
4333                                         if (instance_expr.Type.IsValueType)
4334                                         {
4335                                                 //
4336                                                 // Special case: calls to a function declared in a
4337                                                 // reference-type with a value-type argument need
4338                                                 // to have their value boxed.
4339
4340                                                 struct_call = true;
4341                                                 if (decl_type.IsValueType)
4342                                                 {
4343                                                         //
4344                                                         // If the expression implements IMemoryLocation, then
4345                                                         // we can optimize and use AddressOf on the
4346                                                         // return.
4347                                                         //
4348                                                         // If not we have to use some temporary storage for
4349                                                         // it.
4350                                                         if (instance_expr is IMemoryLocation)
4351                                                         {
4352                                                                 ((IMemoryLocation)instance_expr).
4353                                                                         AddressOf (ec, AddressOp.LoadStore);
4354                                                         }
4355                                                         else
4356                                                         {
4357                                                                 Type t = instance_expr.Type;
4358
4359                                                                 instance_expr.Emit (ec);
4360                                                                 LocalBuilder temp = ig.DeclareLocal (t);
4361                                                                 ig.Emit (OpCodes.Stloc, temp);
4362                                                                 ig.Emit (OpCodes.Ldloca, temp);
4363                                                         }
4364                                                 }
4365                                                 else
4366                                                 {
4367                                                         instance_expr.Emit (ec);
4368                                                         ig.Emit (OpCodes.Box, instance_expr.Type);
4369                                                 }
4370                                         }
4371                                         else
4372                                                 instance_expr.Emit (ec);
4373                                 }
4374                         }
4375
4376                         if (prop_args != null && prop_args.Count > 0)
4377                         {
4378                                 if (Arguments == null)
4379                                         Arguments = new ArrayList();
4380
4381                                 for (int i = prop_args.Count-1; i >=0 ; i--)
4382                                 {
4383                                         Arguments.Insert (0,prop_args[i]);
4384                                 }
4385
4386                         }
4387
4388                         EmitArguments (ec, method, Arguments);
4389
4390                         if (is_static || struct_call || is_base)
4391                         {
4392                                 if (method is MethodInfo)
4393                                 {
4394                                         ig.Emit (OpCodes.Call, (MethodInfo) method);
4395                                 }
4396                                 else
4397                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4398                         }
4399                         else
4400                         {
4401                                 if (method is MethodInfo)
4402                                         ig.Emit (OpCodes.Callvirt, (MethodInfo) method);
4403                                 else
4404                                         ig.Emit (OpCodes.Callvirt, (ConstructorInfo) method);
4405                         }
4406                 }
4407
4408                 static void EmitPropertyArgs (EmitContext ec, ArrayList prop_args)
4409                 {
4410                         int top = prop_args.Count;
4411
4412                         for (int i = 0; i < top; i++)
4413                         {
4414                                 Argument a = (Argument) prop_args [i];
4415                                 a.Emit (ec);
4416                         }
4417                 }
4418
4419                 public override void Emit (EmitContext ec)
4420                 {
4421                         MethodGroupExpr mg = (MethodGroupExpr) this.expr;
4422
4423                         EmitCall (
4424                                 ec, is_base, method.IsStatic, mg.InstanceExpression, method, Arguments, loc);
4425                 }
4426
4427                 public override void EmitStatement (EmitContext ec)
4428                 {
4429                         Emit (ec);
4430
4431                         //
4432                         // Pop the return value if there is one
4433                         //
4434                         if (method is MethodInfo){
4435                                 Type ret = ((MethodInfo)method).ReturnType;
4436                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
4437                                         ec.ig.Emit (OpCodes.Pop);
4438                         }
4439                 }
4440         }
4441
4442         //
4443         // This class is used to "disable" the code generation for the
4444         // temporary variable when initializing value types.
4445         //
4446         class EmptyAddressOf : EmptyExpression, IMemoryLocation {
4447                 public void AddressOf (EmitContext ec, AddressOp Mode)
4448                 {
4449                         // nothing
4450                 }
4451         }
4452
4453         /// <summary>
4454         ///    Implements the new expression
4455         /// </summary>
4456         public class New : ExpressionStatement {
4457                 public readonly ArrayList Arguments;
4458                 public readonly Expression RequestedType;
4459
4460                 MethodBase method = null;
4461
4462                 //
4463                 // If set, the new expression is for a value_target, and
4464                 // we will not leave anything on the stack.
4465                 //
4466                 Expression value_target;
4467                 bool value_target_set = false;
4468
4469                 public New (Expression requested_type, ArrayList arguments, Location l)
4470                 {
4471                         RequestedType = requested_type;
4472                         Arguments = arguments;
4473                         loc = l;
4474                 }
4475
4476                 public Expression ValueTypeVariable {
4477                         get {
4478                                 return value_target;
4479                         }
4480
4481                         set {
4482                                 value_target = value;
4483                                 value_target_set = true;
4484                         }
4485                 }
4486
4487                 //
4488                 // This function is used to disable the following code sequence for
4489                 // value type initialization:
4490                 //
4491                 // AddressOf (temporary)
4492                 // Construct/Init
4493                 // LoadTemporary
4494                 //
4495                 // Instead the provide will have provided us with the address on the
4496                 // stack to store the results.
4497                 //
4498                 static Expression MyEmptyExpression;
4499
4500                 public void DisableTemporaryValueType ()
4501                 {
4502                         if (MyEmptyExpression == null)
4503                                 MyEmptyExpression = new EmptyAddressOf ();
4504
4505                         //
4506                         // To enable this, look into:
4507                         // test-34 and test-89 and self bootstrapping.
4508                         //
4509                         // For instance, we can avoid a copy by using 'newobj'
4510                         // instead of Call + Push-temp on value types.
4511 //                      value_target = MyEmptyExpression;
4512                 }
4513
4514                 public override Expression DoResolve (EmitContext ec)
4515                 {
4516                         type = ec.DeclSpace.ResolveType (RequestedType, false, loc);
4517
4518                         if (type == null)
4519                                 return null;
4520
4521                         bool IsDelegate = TypeManager.IsDelegateType (type);
4522
4523                         if (IsDelegate)
4524                                 return (new NewDelegate (type, Arguments, loc)).Resolve (ec);
4525
4526                         if (type.IsInterface || type.IsAbstract){
4527                                 Error (
4528                                         144, "It is not possible to create instances of interfaces " +
4529                                         "or abstract classes");
4530                                 return null;
4531                         }
4532
4533                         bool is_struct = false;
4534                         is_struct = type.IsValueType;
4535                         eclass = ExprClass.Value;
4536
4537                         //
4538                         // SRE returns a match for .ctor () on structs (the object constructor),
4539                         // so we have to manually ignore it.
4540                         //
4541                         if (is_struct && Arguments == null)
4542                                 return this;
4543
4544                         Expression ml;
4545                         ml = MemberLookupFinal (ec, type, ".ctor",
4546                                                 MemberTypes.Constructor,
4547                                                 AllBindingFlags | BindingFlags.Public, loc);
4548
4549                         if (ml == null)
4550                                 return null;
4551
4552                         if (! (ml is MethodGroupExpr)){
4553                                 if (!is_struct){
4554                                         ml.Error118 ("method group");
4555                                         return null;
4556                                 }
4557                         }
4558
4559                         if (ml != null) {
4560                                 if (Arguments != null){
4561                                         foreach (Argument a in Arguments){
4562                                                 if (!a.Resolve (ec, loc))
4563                                                         return null;
4564                                         }
4565                                 }
4566
4567                                 method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml,
4568                                                                      Arguments, loc);
4569
4570                         }
4571
4572                         if (method == null) {
4573                                 if (!is_struct || Arguments.Count > 0) {
4574                                         Error (1501,
4575                                                "New invocation: Can not find a constructor for " +
4576                                                "this argument list");
4577                                         return null;
4578                                 }
4579                         }
4580                         return this;
4581                 }
4582
4583                 //
4584                 // This DoEmit can be invoked in two contexts:
4585                 //    * As a mechanism that will leave a value on the stack (new object)
4586                 //    * As one that wont (init struct)
4587                 //
4588                 // You can control whether a value is required on the stack by passing
4589                 // need_value_on_stack.  The code *might* leave a value on the stack
4590                 // so it must be popped manually
4591                 //
4592                 // If we are dealing with a ValueType, we have a few
4593                 // situations to deal with:
4594                 //
4595                 //    * The target is a ValueType, and we have been provided
4596                 //      the instance (this is easy, we are being assigned).
4597                 //
4598                 //    * The target of New is being passed as an argument,
4599                 //      to a boxing operation or a function that takes a
4600                 //      ValueType.
4601                 //
4602                 //      In this case, we need to create a temporary variable
4603                 //      that is the argument of New.
4604                 //
4605                 // Returns whether a value is left on the stack
4606                 //
4607                 bool DoEmit (EmitContext ec, bool need_value_on_stack)
4608                 {
4609                         bool is_value_type = type.IsValueType;
4610                         ILGenerator ig = ec.ig;
4611
4612                         if (is_value_type){
4613                                 IMemoryLocation ml;
4614
4615                                 // Allow DoEmit() to be called multiple times.
4616                                 // We need to create a new LocalTemporary each time since
4617                                 // you can't share LocalBuilders among ILGeneators.
4618                                 if (!value_target_set)
4619                                         value_target = new LocalTemporary (ec, type);
4620
4621                                 ml = (IMemoryLocation) value_target;
4622                                 ml.AddressOf (ec, AddressOp.Store);
4623                         }
4624
4625                         if (method != null)
4626                                 Invocation.EmitArguments (ec, method, Arguments);
4627
4628                         if (is_value_type){
4629                                 if (method == null)
4630                                         ig.Emit (OpCodes.Initobj, type);
4631                                 else
4632                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4633                                 if (need_value_on_stack){
4634                                         value_target.Emit (ec);
4635                                         return true;
4636                                 }
4637                                 return false;
4638                         } else {
4639                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) method);
4640                                 return true;
4641                         }
4642                 }
4643
4644                 public override void Emit (EmitContext ec)
4645                 {
4646                         DoEmit (ec, true);
4647                 }
4648
4649                 public override void EmitStatement (EmitContext ec)
4650                 {
4651                         if (DoEmit (ec, false))
4652                                 ec.ig.Emit (OpCodes.Pop);
4653                 }
4654         }
4655
4656         /// <summary>
4657         ///   14.5.10.2: Represents an array creation expression.
4658         /// </summary>
4659         ///
4660         /// <remarks>
4661         ///   There are two possible scenarios here: one is an array creation
4662         ///   expression that specifies the dimensions and optionally the
4663         ///   initialization data and the other which does not need dimensions
4664         ///   specified but where initialization data is mandatory.
4665         /// </remarks>
4666         public class ArrayCreation : ExpressionStatement {
4667                 Expression requested_base_type;
4668                 ArrayList initializers;
4669
4670                 //
4671                 // The list of Argument types.
4672                 // This is used to construct the 'newarray' or constructor signature
4673                 //
4674                 ArrayList arguments;
4675
4676                 //
4677                 // Method used to create the array object.
4678                 //
4679                 MethodBase new_method = null;
4680
4681                 Type array_element_type;
4682                 Type underlying_type;
4683                 bool is_one_dimensional = false;
4684                 bool is_builtin_type = false;
4685                 bool expect_initializers = false;
4686                 int num_arguments = 0;
4687                 int dimensions = 0;
4688                 string rank;
4689
4690                 ArrayList array_data;
4691
4692                 Hashtable bounds;
4693
4694                 //
4695                 // The number of array initializers that we can handle
4696                 // via the InitializeArray method - through EmitStaticInitializers
4697                 //
4698                 int num_automatic_initializers;
4699
4700                 public ArrayCreation (Expression requested_base_type, ArrayList exprs, string rank, ArrayList initializers, Location l)
4701                 {
4702                         this.requested_base_type = requested_base_type;
4703                         this.initializers = initializers;
4704                         this.rank = rank;
4705                         loc = l;
4706
4707                         arguments = new ArrayList ();
4708
4709                         foreach (Expression e in exprs) {
4710                                 arguments.Add (new Argument (e, Argument.AType.Expression));
4711                                 num_arguments++;
4712                         }
4713                 }
4714
4715                 public ArrayCreation (Expression requested_base_type, string rank, ArrayList initializers, Location l)
4716                 {
4717                         this.requested_base_type = requested_base_type;
4718                         this.initializers = initializers;
4719                         this.rank = rank;
4720                         loc = l;
4721
4722                         //this.rank = rank.Substring (0, rank.LastIndexOf ("["));
4723                         //
4724                         //string tmp = rank.Substring (rank.LastIndexOf ("["));
4725                         //
4726                         //dimensions = tmp.Length - 1;
4727                         expect_initializers = true;
4728                 }
4729
4730                 public Expression FormArrayType (Expression base_type, int idx_count, string rank)
4731                 {
4732                         StringBuilder sb = new StringBuilder (rank);
4733
4734                         sb.Append ("[");
4735                         for (int i = 1; i < idx_count; i++)
4736                                 sb.Append (",");
4737
4738                         sb.Append ("]");
4739
4740                         return new ComposedCast (base_type, sb.ToString (), loc);
4741                 }
4742
4743                 void Error_IncorrectArrayInitializer ()
4744                 {
4745                         Error (178, "Incorrectly structured array initializer");
4746                 }
4747
4748                 public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
4749                 {
4750                         if (specified_dims) {
4751                                 Argument a = (Argument) arguments [idx];
4752
4753                                 if (!a.Resolve (ec, loc))
4754                                         return false;
4755
4756                                 if (!(a.Expr is Constant)) {
4757                                         Error (150, "A constant value is expected");
4758                                         return false;
4759                                 }
4760
4761                                 int value = (int) ((Constant) a.Expr).GetValue ();
4762
4763                                 if (value != probe.Count) {
4764                                         Error_IncorrectArrayInitializer ();
4765                                         return false;
4766                                 }
4767
4768                                 bounds [idx] = value;
4769                         }
4770
4771                         int child_bounds = -1;
4772                         foreach (object o in probe) {
4773                                 if (o is ArrayList) {
4774                                         int current_bounds = ((ArrayList) o).Count;
4775
4776                                         if (child_bounds == -1)
4777                                                 child_bounds = current_bounds;
4778
4779                                         else if (child_bounds != current_bounds){
4780                                                 Error_IncorrectArrayInitializer ();
4781                                                 return false;
4782                                         }
4783                                         bool ret = CheckIndices (ec, (ArrayList) o, idx + 1, specified_dims);
4784                                         if (!ret)
4785                                                 return false;
4786                                 } else {
4787                                         if (child_bounds != -1){
4788                                                 Error_IncorrectArrayInitializer ();
4789                                                 return false;
4790                                         }
4791
4792                                         Expression tmp = (Expression) o;
4793                                         tmp = tmp.Resolve (ec);
4794                                         if (tmp == null)
4795                                                 continue;
4796
4797                                         // Console.WriteLine ("I got: " + tmp);
4798                                         // Handle initialization from vars, fields etc.
4799
4800                                         Expression conv = ConvertImplicitRequired (
4801                                                 ec, tmp, underlying_type, loc);
4802
4803                                         if (conv == null)
4804                                                 return false;
4805
4806                                         if (conv is StringConstant)
4807                                                 array_data.Add (conv);
4808                                         else if (conv is Constant) {
4809                                                 array_data.Add (conv);
4810                                                 num_automatic_initializers++;
4811                                         } else
4812                                                 array_data.Add (conv);
4813                                 }
4814                         }
4815
4816                         return true;
4817                 }
4818
4819                 public void UpdateIndices (EmitContext ec)
4820                 {
4821                         int i = 0;
4822                         for (ArrayList probe = initializers; probe != null;) {
4823                                 if (probe.Count > 0 && probe [0] is ArrayList) {
4824                                         Expression e = new IntConstant (probe.Count);
4825                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4826
4827                                         bounds [i++] =  probe.Count;
4828
4829                                         probe = (ArrayList) probe [0];
4830
4831                                 } else {
4832                                         Expression e = new IntConstant (probe.Count);
4833                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4834
4835                                         bounds [i++] = probe.Count;
4836                                         probe = null;
4837                                 }
4838                         }
4839
4840                 }
4841
4842                 public bool ValidateInitializers (EmitContext ec, Type array_type)
4843                 {
4844                         if (initializers == null) {
4845                                 if (expect_initializers)
4846                                         return false;
4847                                 else
4848                                         return true;
4849                         }
4850
4851                         if (underlying_type == null)
4852                                 return false;
4853
4854                         //
4855                         // We use this to store all the date values in the order in which we
4856                         // will need to store them in the byte blob later
4857                         //
4858                         array_data = new ArrayList ();
4859                         bounds = new Hashtable ();
4860
4861                         bool ret;
4862
4863                         if (arguments != null) {
4864                                 ret = CheckIndices (ec, initializers, 0, true);
4865                                 return ret;
4866                         } else {
4867                                 arguments = new ArrayList ();
4868
4869                                 ret = CheckIndices (ec, initializers, 0, false);
4870
4871                                 if (!ret)
4872                                         return false;
4873
4874                                 UpdateIndices (ec);
4875
4876                                 if (arguments.Count != dimensions) {
4877                                         Error_IncorrectArrayInitializer ();
4878                                         return false;
4879                                 }
4880
4881                                 return ret;
4882                         }
4883                 }
4884
4885                 void Error_NegativeArrayIndex ()
4886                 {
4887                         Error (284, "Can not create array with a negative size");
4888                 }
4889
4890                 //
4891                 // Converts 'source' to an int, uint, long or ulong.
4892                 //
4893                 Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
4894                 {
4895                         Expression target;
4896
4897                         bool old_checked = ec.CheckState;
4898                         ec.CheckState = true;
4899
4900                         target = ConvertImplicit (ec, source, TypeManager.int32_type, loc);
4901                         if (target == null){
4902                                 target = ConvertImplicit (ec, source, TypeManager.uint32_type, loc);
4903                                 if (target == null){
4904                                         target = ConvertImplicit (ec, source, TypeManager.int64_type, loc);
4905                                         if (target == null){
4906                                                 target = ConvertImplicit (ec, source, TypeManager.uint64_type, loc);
4907                                                 if (target == null)
4908                                                         Expression.Error_CannotConvertImplicit (loc, source.Type, TypeManager.int32_type);
4909                                         }
4910                                 }
4911                         }
4912                         ec.CheckState = old_checked;
4913
4914                         //
4915                         // Only positive constants are allowed at compile time
4916                         //
4917                         if (target is Constant){
4918                                 if (target is IntConstant){
4919                                         if (((IntConstant) target).Value < 0){
4920                                                 Error_NegativeArrayIndex ();
4921                                                 return null;
4922                                         }
4923                                 }
4924
4925                                 if (target is LongConstant){
4926                                         if (((LongConstant) target).Value < 0){
4927                                                 Error_NegativeArrayIndex ();
4928                                                 return null;
4929                                         }
4930                                 }
4931
4932                         }
4933
4934                         return target;
4935                 }
4936
4937                 //
4938                 // Creates the type of the array
4939                 //
4940                 bool LookupType (EmitContext ec)
4941                 {
4942                         StringBuilder array_qualifier = new StringBuilder (rank);
4943
4944                         //
4945                         // 'In the first form allocates an array instace of the type that results
4946                         // from deleting each of the individual expression from the expression list'
4947                         //
4948                         if (num_arguments > 0) {
4949                                 array_qualifier.Append ("[");
4950                                 for (int i = num_arguments-1; i > 0; i--)
4951                                         array_qualifier.Append (",");
4952                                 array_qualifier.Append ("]");
4953                         }
4954
4955                         //
4956                         // Lookup the type
4957                         //
4958                         Expression array_type_expr;
4959                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
4960                         string sss = array_qualifier.ToString ();
4961                         type = ec.DeclSpace.ResolveType (array_type_expr, false, loc);
4962
4963                         if (type == null)
4964                                 return false;
4965
4966                         underlying_type = type;
4967                         if (underlying_type.IsArray)
4968                                 underlying_type = TypeManager.TypeToCoreType (underlying_type.GetElementType ());
4969                         dimensions = type.GetArrayRank ();
4970
4971                         return true;
4972                 }
4973
4974                 public override Expression DoResolve (EmitContext ec)
4975                 {
4976                         int arg_count;
4977
4978                         if (!LookupType (ec))
4979                                 return null;
4980
4981                         //
4982                         // First step is to validate the initializers and fill
4983                         // in any missing bits
4984                         //
4985                         if (!ValidateInitializers (ec, type))
4986                                 return null;
4987
4988                         if (arguments == null)
4989                                 arg_count = 0;
4990                         else {
4991                                 arg_count = arguments.Count;
4992                                 foreach (Argument a in arguments){
4993                                         if (!a.Resolve (ec, loc))
4994                                                 return null;
4995
4996                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
4997                                         if (real_arg == null)
4998                                                 return null;
4999
5000                                         a.Expr = real_arg;
5001                                 }
5002                         }
5003
5004                         array_element_type = TypeManager.TypeToCoreType (type.GetElementType ());
5005
5006                         if (arg_count == 1) {
5007                                 is_one_dimensional = true;
5008                                 eclass = ExprClass.Value;
5009                                 return this;
5010                         }
5011
5012                         is_builtin_type = TypeManager.IsBuiltinType (type);
5013
5014                         if (is_builtin_type) {
5015                                 Expression ml;
5016
5017                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
5018                                                    AllBindingFlags, loc);
5019
5020                                 if (!(ml is MethodGroupExpr)) {
5021                                         ml.Error118 ("method group");
5022                                         return null;
5023                                 }
5024
5025                                 if (ml == null) {
5026                                         Error (-6, "New invocation: Can not find a constructor for " +
5027                                                       "this argument list");
5028                                         return null;
5029                                 }
5030
5031                                 new_method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml, arguments, loc);
5032
5033                                 if (new_method == null) {
5034                                         Error (-6, "New invocation: Can not find a constructor for " +
5035                                                       "this argument list");
5036                                         return null;
5037                                 }
5038
5039                                 eclass = ExprClass.Value;
5040                                 return this;
5041                         } else {
5042                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
5043                                 ArrayList args = new ArrayList ();
5044
5045                                 if (arguments != null) {
5046                                         for (int i = 0; i < arg_count; i++)
5047                                                 args.Add (TypeManager.int32_type);
5048                                 }
5049
5050                                 Type [] arg_types = null;
5051
5052                                 if (args.Count > 0)
5053                                         arg_types = new Type [args.Count];
5054
5055                                 args.CopyTo (arg_types, 0);
5056
5057                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
5058                                                             arg_types);
5059
5060                                 if (new_method == null) {
5061                                         Error (-6, "New invocation: Can not find a constructor for " +
5062                                                       "this argument list");
5063                                         return null;
5064                                 }
5065
5066                                 eclass = ExprClass.Value;
5067                                 return this;
5068                         }
5069                 }
5070
5071                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
5072                 {
5073                         int factor;
5074                         byte [] data;
5075                         byte [] element;
5076                         int count = array_data.Count;
5077
5078                         if (underlying_type.IsEnum)
5079                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
5080
5081                         factor = GetTypeSize (underlying_type);
5082                         if (factor == 0)
5083                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
5084
5085                         data = new byte [(count * factor + 4) & ~3];
5086                         int idx = 0;
5087
5088                         for (int i = 0; i < count; ++i) {
5089                                 object v = array_data [i];
5090
5091                                 if (v is EnumConstant)
5092                                         v = ((EnumConstant) v).Child;
5093
5094                                 if (v is Constant && !(v is StringConstant))
5095                                         v = ((Constant) v).GetValue ();
5096                                 else {
5097                                         idx += factor;
5098                                         continue;
5099                                 }
5100
5101                                 if (underlying_type == TypeManager.int64_type){
5102                                         if (!(v is Expression)){
5103                                                 long val = (long) v;
5104
5105                                                 for (int j = 0; j < factor; ++j) {
5106                                                         data [idx + j] = (byte) (val & 0xFF);
5107                                                         val = (val >> 8);
5108                                                 }
5109                                         }
5110                                 } else if (underlying_type == TypeManager.uint64_type){
5111                                         if (!(v is Expression)){
5112                                                 ulong val = (ulong) v;
5113
5114                                                 for (int j = 0; j < factor; ++j) {
5115                                                         data [idx + j] = (byte) (val & 0xFF);
5116                                                         val = (val >> 8);
5117                                                 }
5118                                         }
5119                                 } else if (underlying_type == TypeManager.float_type) {
5120                                         if (!(v is Expression)){
5121                                                 element = BitConverter.GetBytes ((float) v);
5122
5123                                                 for (int j = 0; j < factor; ++j)
5124                                                         data [idx + j] = element [j];
5125                                         }
5126                                 } else if (underlying_type == TypeManager.double_type) {
5127                                         if (!(v is Expression)){
5128                                                 element = BitConverter.GetBytes ((double) v);
5129
5130                                                 for (int j = 0; j < factor; ++j)
5131                                                         data [idx + j] = element [j];
5132                                         }
5133                                 } else if (underlying_type == TypeManager.char_type){
5134                                         if (!(v is Expression)){
5135                                                 int val = (int) ((char) v);
5136
5137                                                 data [idx] = (byte) (val & 0xff);
5138                                                 data [idx+1] = (byte) (val >> 8);
5139                                         }
5140                                 } else if (underlying_type == TypeManager.short_type){
5141                                         if (!(v is Expression)){
5142                                                 int val = (int) ((short) v);
5143
5144                                                 data [idx] = (byte) (val & 0xff);
5145                                                 data [idx+1] = (byte) (val >> 8);
5146                                         }
5147                                 } else if (underlying_type == TypeManager.ushort_type){
5148                                         if (!(v is Expression)){
5149                                                 int val = (int) ((ushort) v);
5150
5151                                                 data [idx] = (byte) (val & 0xff);
5152                                                 data [idx+1] = (byte) (val >> 8);
5153                                         }
5154                                 } else if (underlying_type == TypeManager.int32_type) {
5155                                         if (!(v is Expression)){
5156                                                 int val = (int) v;
5157
5158                                                 data [idx]   = (byte) (val & 0xff);
5159                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
5160                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
5161                                                 data [idx+3] = (byte) (val >> 24);
5162                                         }
5163                                 } else if (underlying_type == TypeManager.uint32_type) {
5164                                         if (!(v is Expression)){
5165                                                 uint val = (uint) v;
5166
5167                                                 data [idx]   = (byte) (val & 0xff);
5168                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
5169                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
5170                                                 data [idx+3] = (byte) (val >> 24);
5171                                         }
5172                                 } else if (underlying_type == TypeManager.sbyte_type) {
5173                                         if (!(v is Expression)){
5174                                                 sbyte val = (sbyte) v;
5175                                                 data [idx] = (byte) val;
5176                                         }
5177                                 } else if (underlying_type == TypeManager.byte_type) {
5178                                         if (!(v is Expression)){
5179                                                 byte val = (byte) v;
5180                                                 data [idx] = (byte) val;
5181                                         }
5182                                 } else if (underlying_type == TypeManager.bool_type) {
5183                                         if (!(v is Expression)){
5184                                                 bool val = (bool) v;
5185                                                 data [idx] = (byte) (val ? 1 : 0);
5186                                         }
5187                                 } else if (underlying_type == TypeManager.decimal_type){
5188                                         if (!(v is Expression)){
5189                                                 int [] bits = Decimal.GetBits ((decimal) v);
5190                                                 int p = idx;
5191
5192                                                 for (int j = 0; j < 4; j++){
5193                                                         data [p++] = (byte) (bits [j] & 0xff);
5194                                                         data [p++] = (byte) ((bits [j] >> 8) & 0xff);
5195                                                         data [p++] = (byte) ((bits [j] >> 16) & 0xff);
5196                                                         data [p++] = (byte) (bits [j] >> 24);
5197                                                 }
5198                                         }
5199                                 } else
5200                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
5201
5202                                 idx += factor;
5203                         }
5204
5205                         return data;
5206                 }
5207
5208                 //
5209                 // Emits the initializers for the array
5210                 //
5211                 void EmitStaticInitializers (EmitContext ec, bool is_expression)
5212                 {
5213                         //
5214                         // First, the static data
5215                         //
5216                         FieldBuilder fb;
5217                         ILGenerator ig = ec.ig;
5218
5219                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
5220
5221                         fb = RootContext.MakeStaticData (data);
5222
5223                         if (is_expression)
5224                                 ig.Emit (OpCodes.Dup);
5225                         ig.Emit (OpCodes.Ldtoken, fb);
5226                         ig.Emit (OpCodes.Call,
5227                                  TypeManager.void_initializearray_array_fieldhandle);
5228                 }
5229
5230                 //
5231                 // Emits pieces of the array that can not be computed at compile
5232                 // time (variables and string locations).
5233                 //
5234                 // This always expect the top value on the stack to be the array
5235                 //
5236                 void EmitDynamicInitializers (EmitContext ec, bool is_expression)
5237                 {
5238                         ILGenerator ig = ec.ig;
5239                         int dims = bounds.Count;
5240                         int [] current_pos = new int [dims];
5241                         int top = array_data.Count;
5242                         LocalBuilder temp = ig.DeclareLocal (type);
5243
5244                         ig.Emit (OpCodes.Stloc, temp);
5245
5246                         MethodInfo set = null;
5247
5248                         if (dims != 1){
5249                                 Type [] args;
5250                                 ModuleBuilder mb = null;
5251                                 mb = CodeGen.ModuleBuilder;
5252                                 args = new Type [dims + 1];
5253
5254                                 int j;
5255                                 for (j = 0; j < dims; j++)
5256                                         args [j] = TypeManager.int32_type;
5257
5258                                 args [j] = array_element_type;
5259
5260                                 set = mb.GetArrayMethod (
5261                                         type, "Set",
5262                                         CallingConventions.HasThis | CallingConventions.Standard,
5263                                         TypeManager.void_type, args);
5264                         }
5265
5266                         for (int i = 0; i < top; i++){
5267
5268                                 Expression e = null;
5269
5270                                 if (array_data [i] is Expression)
5271                                         e = (Expression) array_data [i];
5272
5273                                 if (e != null) {
5274                                         //
5275                                         // Basically we do this for string literals and
5276                                         // other non-literal expressions
5277                                         //
5278                                         if (e is StringConstant || !(e is Constant) ||
5279                                             num_automatic_initializers <= 2) {
5280                                                 Type etype = e.Type;
5281
5282                                                 ig.Emit (OpCodes.Ldloc, temp);
5283
5284                                                 for (int idx = 0; idx < dims; idx++)
5285                                                         IntConstant.EmitInt (ig, current_pos [idx]);
5286
5287                                                 //
5288                                                 // If we are dealing with a struct, get the
5289                                                 // address of it, so we can store it.
5290                                                 //
5291                                                 if ((dims == 1) &&
5292                                                     etype.IsSubclassOf (TypeManager.value_type) &&
5293                                                     (!TypeManager.IsBuiltinType (etype) ||
5294                                                      etype == TypeManager.decimal_type)) {
5295                                                         if (e is New){
5296                                                                 New n = (New) e;
5297
5298                                                                 //
5299                                                                 // Let new know that we are providing
5300                                                                 // the address where to store the results
5301                                                                 //
5302                                                                 n.DisableTemporaryValueType ();
5303                                                         }
5304
5305                                                         ig.Emit (OpCodes.Ldelema, etype);
5306                                                 }
5307
5308                                                 e.Emit (ec);
5309
5310                                                 if (dims == 1)
5311                                                         ArrayAccess.EmitStoreOpcode (ig, array_element_type);
5312                                                 else
5313                                                         ig.Emit (OpCodes.Call, set);
5314                                         }
5315                                 }
5316
5317                                 //
5318                                 // Advance counter
5319                                 //
5320                                 for (int j = dims - 1; j >= 0; j--){
5321                                         current_pos [j]++;
5322                                         if (current_pos [j] < (int) bounds [j])
5323                                                 break;
5324                                         current_pos [j] = 0;
5325                                 }
5326                         }
5327
5328                         if (is_expression)
5329                                 ig.Emit (OpCodes.Ldloc, temp);
5330                 }
5331
5332                 void EmitArrayArguments (EmitContext ec)
5333                 {
5334                         ILGenerator ig = ec.ig;
5335
5336                         foreach (Argument a in arguments) {
5337                                 Type atype = a.Type;
5338                                 a.Emit (ec);
5339
5340                                 if (atype == TypeManager.uint64_type)
5341                                         ig.Emit (OpCodes.Conv_Ovf_U4);
5342                                 else if (atype == TypeManager.int64_type)
5343                                         ig.Emit (OpCodes.Conv_Ovf_I4);
5344                         }
5345                 }
5346
5347                 void DoEmit (EmitContext ec, bool is_statement)
5348                 {
5349                         ILGenerator ig = ec.ig;
5350
5351                         EmitArrayArguments (ec);
5352                         if (is_one_dimensional)
5353                                 ig.Emit (OpCodes.Newarr, array_element_type);
5354                         else {
5355                                 if (is_builtin_type)
5356                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
5357                                 else
5358                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
5359                         }
5360
5361                         if (initializers != null){
5362                                 //
5363                                 // FIXME: Set this variable correctly.
5364                                 //
5365                                 bool dynamic_initializers = true;
5366
5367                                 if (underlying_type != TypeManager.string_type &&
5368                                     underlying_type != TypeManager.object_type) {
5369                                         if (num_automatic_initializers > 2)
5370                                                 EmitStaticInitializers (ec, dynamic_initializers || !is_statement);
5371                                 }
5372
5373                                 if (dynamic_initializers)
5374                                         EmitDynamicInitializers (ec, !is_statement);
5375                         }
5376                 }
5377
5378                 public override void Emit (EmitContext ec)
5379                 {
5380                         DoEmit (ec, false);
5381                 }
5382
5383                 public override void EmitStatement (EmitContext ec)
5384                 {
5385                         DoEmit (ec, true);
5386                 }
5387
5388         }
5389
5390         /// <summary>
5391         ///   Represents the 'this' construct
5392         /// </summary>
5393         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
5394
5395                 Block block;
5396                 VariableInfo vi;
5397
5398                 public This (Block block, Location loc)
5399                 {
5400                         this.loc = loc;
5401                         this.block = block;
5402                 }
5403
5404                 public This (Location loc)
5405                 {
5406                         this.loc = loc;
5407                 }
5408
5409                 public bool IsAssigned (EmitContext ec, Location loc)
5410                 {
5411                         if (vi == null)
5412                                 return true;
5413
5414                         return vi.IsAssigned (ec, loc);
5415                 }
5416
5417                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
5418                 {
5419                         if (vi == null)
5420                                 return true;
5421
5422                         return vi.IsFieldAssigned (ec, field_name, loc);
5423                 }
5424
5425                 public void SetAssigned (EmitContext ec)
5426                 {
5427                         if (vi != null)
5428                                 vi.SetAssigned (ec);
5429                 }
5430
5431                 public void SetFieldAssigned (EmitContext ec, string field_name)
5432                 {
5433                         if (vi != null)
5434                                 vi.SetFieldAssigned (ec, field_name);
5435                 }
5436
5437                 public override Expression DoResolve (EmitContext ec)
5438                 {
5439                         eclass = ExprClass.Variable;
5440                         type = ec.ContainerType;
5441
5442                         if (ec.IsStatic){
5443                                 Error (26, "Keyword this not valid in static code");
5444                                 return null;
5445                         }
5446
5447                         if (block != null)
5448                                 vi = block.ThisVariable;
5449
5450                         return this;
5451                 }
5452
5453                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5454                 {
5455                         DoResolve (ec);
5456
5457                         VariableInfo vi = ec.CurrentBlock.ThisVariable;
5458                         if (vi != null)
5459                                 vi.SetAssigned (ec);
5460
5461                         if (ec.TypeContainer is Class){
5462                                 Error (1604, "Cannot assign to 'this'");
5463                                 return null;
5464                         }
5465
5466                         return this;
5467                 }
5468
5469                 public override void Emit (EmitContext ec)
5470                 {
5471                         ILGenerator ig = ec.ig;
5472
5473                         ig.Emit (OpCodes.Ldarg_0);
5474                         if (ec.TypeContainer is Struct)
5475                                 ig.Emit (OpCodes.Ldobj, type);
5476                 }
5477
5478                 public void EmitAssign (EmitContext ec, Expression source)
5479                 {
5480                         ILGenerator ig = ec.ig;
5481
5482                         if (ec.TypeContainer is Struct){
5483                                 ig.Emit (OpCodes.Ldarg_0);
5484                                 source.Emit (ec);
5485                                 ig.Emit (OpCodes.Stobj, type);
5486                         } else {
5487                                 source.Emit (ec);
5488                                 ig.Emit (OpCodes.Starg, 0);
5489                         }
5490                 }
5491
5492                 public void AddressOf (EmitContext ec, AddressOp mode)
5493                 {
5494                         ec.ig.Emit (OpCodes.Ldarg_0);
5495
5496                         // FIMXE
5497                         // FIGURE OUT WHY LDARG_S does not work
5498                         //
5499                         // consider: struct X { int val; int P { set { val = value; }}}
5500                         //
5501                         // Yes, this looks very bad. Look at 'NOTAS' for
5502                         // an explanation.
5503                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
5504                 }
5505         }
5506
5507         /// <summary>
5508         ///   Implements the typeof operator
5509         /// </summary>
5510         public class TypeOf : Expression {
5511                 public readonly Expression QueriedType;
5512                 Type typearg;
5513
5514                 public TypeOf (Expression queried_type, Location l)
5515                 {
5516                         QueriedType = queried_type;
5517                         loc = l;
5518                 }
5519
5520                 public override Expression DoResolve (EmitContext ec)
5521                 {
5522                         typearg = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5523
5524                         if (typearg == null)
5525                                 return null;
5526
5527                         type = TypeManager.type_type;
5528                         eclass = ExprClass.Type;
5529                         return this;
5530                 }
5531
5532                 public override void Emit (EmitContext ec)
5533                 {
5534                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
5535                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
5536                 }
5537
5538                 public Type TypeArg {
5539                         get { return typearg; }
5540                 }
5541         }
5542
5543         /// <summary>
5544         ///   Implements the sizeof expression
5545         /// </summary>
5546         public class SizeOf : Expression {
5547                 public readonly Expression QueriedType;
5548                 Type type_queried;
5549
5550                 public SizeOf (Expression queried_type, Location l)
5551                 {
5552                         this.QueriedType = queried_type;
5553                         loc = l;
5554                 }
5555
5556                 public override Expression DoResolve (EmitContext ec)
5557                 {
5558                         if (!ec.InUnsafe) {
5559                                 Error (233, "Sizeof may only be used in an unsafe context " +
5560                                        "(consider using System.Runtime.InteropServices.Marshal.Sizeof");
5561                                 return null;
5562                         }
5563
5564                         type_queried = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5565                         if (type_queried == null)
5566                                 return null;
5567
5568                         if (!TypeManager.IsUnmanagedType (type_queried)){
5569                                 Report.Error (208, "Cannot take the size of an unmanaged type (" + TypeManager.MonoBASIC_Name (type_queried) + ")");
5570                                 return null;
5571                         }
5572
5573                         type = TypeManager.int32_type;
5574                         eclass = ExprClass.Value;
5575                         return this;
5576                 }
5577
5578                 public override void Emit (EmitContext ec)
5579                 {
5580                         int size = GetTypeSize (type_queried);
5581
5582                         if (size == 0)
5583                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
5584                         else
5585                                 IntConstant.EmitInt (ec.ig, size);
5586                 }
5587         }
5588
5589         /// <summary>
5590         ///   Implements the member access expression
5591         /// </summary>
5592         public class MemberAccess : Expression, ITypeExpression {
5593                 public readonly string Identifier;
5594                 Expression expr;
5595                 Expression member_lookup;
5596
5597                 public MemberAccess (Expression expr, string id, Location l)
5598                 {
5599                         this.expr = expr;
5600                         Identifier = id;
5601                         loc = l;
5602                 }
5603
5604                 public Expression Expr {
5605                         get {
5606                                 return expr;
5607                         }
5608                 }
5609
5610                 static void error176 (Location loc, string name)
5611                 {
5612                         Report.Error (176, loc, "Static member '" +
5613                                       name + "' cannot be accessed " +
5614                                       "with an instance reference, qualify with a " +
5615                                       "type name instead");
5616                 }
5617
5618                 static bool IdenticalNameAndTypeName (EmitContext ec, Expression left_original, Location loc)
5619                 {
5620                         if (left_original == null)
5621                                 return false;
5622
5623                         if (!(left_original is SimpleName))
5624                                 return false;
5625
5626                         SimpleName sn = (SimpleName) left_original;
5627
5628                         Type t = RootContext.LookupType (ec.DeclSpace, sn.Name, true, loc);
5629                         if (t != null)
5630                                 return true;
5631
5632                         return false;
5633                 }
5634
5635                 public static Expression ResolveMemberAccess (EmitContext ec, Expression member_lookup,
5636                                                               Expression left, Location loc,
5637                                                               Expression left_original)
5638                 {
5639                         bool left_is_type, left_is_explicit;
5640
5641                         // If 'left' is null, then we're called from SimpleNameResolve and this is
5642                         // a member in the currently defining class.
5643                         if (left == null) {
5644                                 left_is_type = ec.IsStatic || ec.IsFieldInitializer;
5645                                 left_is_explicit = false;
5646
5647                                 // Implicitly default to 'this' unless we're static.
5648                                 if (!ec.IsStatic && !ec.IsFieldInitializer && !ec.InEnumContext)
5649                                         left = ec.This;
5650                         } else {
5651                                 left_is_type = left is TypeExpr;
5652                                 left_is_explicit = true;
5653                         }
5654
5655                         if (member_lookup is FieldExpr){
5656                                 FieldExpr fe = (FieldExpr) member_lookup;
5657                                 FieldInfo fi = fe.FieldInfo;
5658                                 Type decl_type = fi.DeclaringType;
5659
5660                                 if (fi is FieldBuilder) {
5661                                         Const c = TypeManager.LookupConstant ((FieldBuilder) fi);
5662
5663                                         if (c != null) {
5664                                                 object o = c.LookupConstantValue (ec);
5665                                                 object real_value = ((Constant) c.Expr).GetValue ();
5666
5667                                                 return Constantify (real_value, fi.FieldType);
5668                                         }
5669                                 }
5670
5671                                 if (fi.IsLiteral) {
5672                                         Type t = fi.FieldType;
5673
5674                                         object o;
5675
5676                                         if (fi is FieldBuilder)
5677                                                 o = TypeManager.GetValue ((FieldBuilder) fi);
5678                                         else
5679                                                 o = fi.GetValue (fi);
5680
5681                                         if (decl_type.IsSubclassOf (TypeManager.enum_type)) {
5682                                                 if (left_is_explicit && !left_is_type &&
5683                                                     !IdenticalNameAndTypeName (ec, left_original, loc)) {
5684                                                         error176 (loc, fe.FieldInfo.Name);
5685                                                         return null;
5686                                                 }
5687
5688                                                 Expression enum_member = MemberLookup (
5689                                                         ec, decl_type, "value__", MemberTypes.Field,
5690                                                         AllBindingFlags, loc);
5691
5692                                                 Enum en = TypeManager.LookupEnum (decl_type);
5693
5694                                                 Constant c;
5695                                                 if (en != null)
5696                                                         c = Constantify (o, en.UnderlyingType);
5697                                                 else
5698                                                         c = Constantify (o, enum_member.Type);
5699
5700                                                 return new EnumConstant (c, decl_type);
5701                                         }
5702
5703                                         Expression exp = Constantify (o, t);
5704
5705                                         if (left_is_explicit && !left_is_type) {
5706                                                 error176 (loc, fe.FieldInfo.Name);
5707                                                 return null;
5708                                         }
5709
5710                                         return exp;
5711                                 }
5712
5713                                 if (fi.FieldType.IsPointer && !ec.InUnsafe){
5714                                         UnsafeError (loc);
5715                                         return null;
5716                                 }
5717                         }
5718
5719                         if (member_lookup is EventExpr) {
5720
5721                                 EventExpr ee = (EventExpr) member_lookup;
5722
5723                                 //
5724                                 // If the event is local to this class, we transform ourselves into
5725                                 // a FieldExpr
5726                                 //
5727
5728                                 if (ee.EventInfo.DeclaringType == ec.ContainerType) {
5729                                         MemberInfo mi = GetFieldFromEvent (ee);
5730
5731                                         if (mi == null) {
5732                                                 //
5733                                                 // If this happens, then we have an event with its own
5734                                                 // accessors and private field etc so there's no need
5735                                                 // to transform ourselves : we should instead flag an error
5736                                                 //
5737                                                 Assign.error70 (ee.EventInfo, loc);
5738                                                 return null;
5739                                         }
5740
5741                                         Expression ml = ExprClassFromMemberInfo (ec, mi, loc);
5742
5743                                         if (ml == null) {
5744                                                 Report.Error (-200, loc, "Internal error!!");
5745                                                 return null;
5746                                         }
5747
5748                                         return ResolveMemberAccess (ec, ml, left, loc, left_original);
5749                                 }
5750                         }
5751
5752                         if (member_lookup is IMemberExpr) {
5753                                 IMemberExpr me = (IMemberExpr) member_lookup;
5754
5755                                 if (left_is_type){
5756                                         MethodGroupExpr mg = me as MethodGroupExpr;
5757                                         if ((mg != null) && left_is_explicit && left.Type.IsInterface)
5758                                                 mg.IsExplicitImpl = left_is_explicit;
5759
5760                                         if (!me.IsStatic){
5761                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5762                                                         return member_lookup;
5763
5764                                                 SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
5765                                                 return null;
5766                                         }
5767
5768                                 } else {
5769                                         if (!me.IsInstance){
5770                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5771                                                         return member_lookup;
5772
5773                                                 if (left_is_explicit) {
5774                                                         error176 (loc, me.Name);
5775                                                         return null;
5776                                                 }
5777                                         }
5778
5779                                         //
5780                                         // Since we can not check for instance objects in SimpleName,
5781                                         // becaue of the rule that allows types and variables to share
5782                                         // the name (as long as they can be de-ambiguated later, see
5783                                         // IdenticalNameAndTypeName), we have to check whether left
5784                                         // is an instance variable in a static context
5785                                         //
5786                                         // However, if the left-hand value is explicitly given, then
5787                                         // it is already our instance expression, so we aren't in
5788                                         // static context.
5789                                         //
5790
5791                                         if (ec.IsStatic && !left_is_explicit && left is IMemberExpr){
5792                                                 IMemberExpr mexp = (IMemberExpr) left;
5793
5794                                                 if (!mexp.IsStatic){
5795                                                         SimpleName.Error_ObjectRefRequired (ec, loc, mexp.Name);
5796                                                         return null;
5797                                                 }
5798                                         }
5799
5800                                         me.InstanceExpression = left;
5801                                 }
5802
5803                                 return member_lookup;
5804                         }
5805
5806                         if (member_lookup is TypeExpr){
5807                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5808                                 return member_lookup;
5809                         }
5810
5811                         Console.WriteLine ("Left is: " + left);
5812                         Report.Error (-100, loc, "Support for [" + member_lookup + "] is not present yet");
5813                         Environment.Exit (0);
5814                         return null;
5815                 }
5816
5817                 public Expression DoResolve (EmitContext ec, Expression right_side, ResolveFlags flags)
5818                 {
5819                         if (type != null)
5820                                 throw new Exception ();
5821                         //
5822                         // Resolve the expression with flow analysis turned off, we'll do the definite
5823                         // assignment checks later.  This is because we don't know yet what the expression
5824                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
5825                         // definite assignment check on the actual field and not on the whole struct.
5826                         //
5827
5828                         Expression original = expr;
5829                         expr = expr.Resolve (ec, flags | ResolveFlags.DisableFlowAnalysis);
5830
5831                         if (expr == null)
5832                                 return null;
5833
5834                         if (expr is SimpleName){
5835                                 SimpleName child_expr = (SimpleName) expr;
5836
5837                                 Expression new_expr = new SimpleName (child_expr.Name + "." + Identifier, loc);
5838
5839                                 return new_expr.Resolve (ec, flags);
5840                         }
5841
5842                         //
5843                         // TODO: I mailed Ravi about this, and apparently we can get rid
5844                         // of this and put it in the right place.
5845                         //
5846                         // Handle enums here when they are in transit.
5847                         // Note that we cannot afford to hit MemberLookup in this case because
5848                         // it will fail to find any members at all
5849                         //
5850
5851                         int errors = Report.Errors;
5852
5853                         Type expr_type = expr.Type;
5854                         if ((expr is TypeExpr) && (expr_type.IsSubclassOf (TypeManager.enum_type))){
5855
5856                                 Enum en = TypeManager.LookupEnum (expr_type);
5857
5858                                 if (en != null) {
5859                                         object value = en.LookupEnumValue (ec, Identifier, loc);
5860
5861                                         if (value != null){
5862                                                 Constant c = Constantify (value, en.UnderlyingType);
5863                                                 return new EnumConstant (c, expr_type);
5864                                         }
5865                                 }
5866                         }
5867
5868                         if (expr_type.IsPointer){
5869                                 Error (23, "The '.' operator can not be applied to pointer operands (" +
5870                                        TypeManager.MonoBASIC_Name (expr_type) + ")");
5871                                 return null;
5872                         }
5873
5874                         member_lookup = MemberLookup (ec, expr_type, Identifier, loc);
5875
5876                         if (member_lookup == null)
5877                         {
5878                                 // Error has already been reported.
5879                                 if (errors < Report.Errors)
5880                                         return null;
5881
5882                                 //
5883                                 // Try looking the member up from the same type, if we find
5884                                 // it, we know that the error was due to limited visibility
5885                                 //
5886                                 object lookup = TypeManager.MemberLookup (
5887                                         expr_type, expr_type, AllMemberTypes, AllBindingFlags |
5888                                         BindingFlags.NonPublic, Identifier);
5889
5890                                 if (lookup == null)
5891                                         Error (117, "'" + expr_type + "' does not contain a definition for '" + Identifier + "'");
5892                                 else
5893                                 {
5894                                         if ((expr_type != ec.ContainerType) &&
5895                                                  ec.ContainerType.IsSubclassOf (expr_type))
5896                                         {
5897
5898                                                 // Although a derived class can access protected members of
5899                                                 // its base class it cannot do so through an instance of the
5900                                                 // base class (CS1540).  If the expr_type is a parent of the
5901                                                 // ec.ContainerType and the lookup succeeds with the latter one,
5902                                                 // then we are in this situation.
5903
5904                                                 lookup = TypeManager.MemberLookup(
5905                                                                         ec.ContainerType, ec.ContainerType, AllMemberTypes,
5906                                                                         AllBindingFlags, Identifier);
5907
5908                                                 if (lookup != null)
5909                                                         Error (1540, "Cannot access protected member '" +
5910                                                        expr_type + "." + Identifier + "' " +
5911                                                        "via a qualifier of type '" + TypeManager.MonoBASIC_Name (expr_type) + "'; the " +
5912                                                        "qualifier must be of type '" + TypeManager.MonoBASIC_Name (ec.ContainerType) + "' " +
5913                                                        "(or derived from it)");
5914                                                 else
5915                                                         Error (122, "'" + expr_type + "." + Identifier + "' " +
5916                                                        "is inaccessible because of its protection level");
5917                                         } else
5918                                                 Error (122, "'" + expr_type + "." + Identifier + "' " +
5919                                                "is inaccessible because of its protection level");
5920                                 }
5921                                 return null;
5922                         }
5923
5924                         if (member_lookup is TypeExpr){
5925                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5926                                 return member_lookup;
5927                         } else if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
5928                                 return null;
5929
5930                         member_lookup = ResolveMemberAccess (ec, member_lookup, expr, loc, original);
5931                         if (member_lookup == null)
5932                                 return null;
5933
5934                         // The following DoResolve/DoResolveLValue will do the definite assignment
5935                         // check.
5936
5937                         if (right_side != null)
5938                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
5939                         else
5940                                 member_lookup = member_lookup.DoResolve (ec);
5941
5942                         return member_lookup;
5943                 }
5944
5945                 public override Expression DoResolve (EmitContext ec)
5946                 {
5947                         return DoResolve (ec, null, ResolveFlags.VariableOrValue |
5948                                           ResolveFlags.SimpleName | ResolveFlags.Type);
5949                 }
5950
5951                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5952                 {
5953                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue |
5954                                           ResolveFlags.SimpleName | ResolveFlags.Type);
5955                 }
5956
5957                 public Expression DoResolveType (EmitContext ec)
5958                 {
5959                         return DoResolve (ec, null, ResolveFlags.Type);
5960                 }
5961
5962                 public override void Emit (EmitContext ec)
5963                 {
5964                         throw new Exception ("Should not happen");
5965                 }
5966
5967                 public override string ToString ()
5968                 {
5969                         return expr + "." + Identifier;
5970                 }
5971         }
5972
5973
5974
5975         /// <summary>
5976         ///   Implements checked expressions
5977         /// </summary>
5978         public class CheckedExpr : Expression {
5979
5980                 public Expression Expr;
5981
5982                 public CheckedExpr (Expression e, Location l)
5983                 {
5984                         Expr = e;
5985                         loc = l;
5986                 }
5987
5988                 public override Expression DoResolve (EmitContext ec)
5989                 {
5990                         bool last_const_check = ec.ConstantCheckState;
5991
5992                         ec.ConstantCheckState = true;
5993                         Expr = Expr.Resolve (ec);
5994                         ec.ConstantCheckState = last_const_check;
5995
5996                         if (Expr == null)
5997                                 return null;
5998
5999                         if (Expr is Constant)
6000                                 return Expr;
6001
6002                         eclass = Expr.eclass;
6003                         type = Expr.Type;
6004                         return this;
6005                 }
6006
6007                 public override void Emit (EmitContext ec)
6008                 {
6009                         bool last_check = ec.CheckState;
6010                         bool last_const_check = ec.ConstantCheckState;
6011
6012                         ec.CheckState = true;
6013                         ec.ConstantCheckState = true;
6014                         Expr.Emit (ec);
6015                         ec.CheckState = last_check;
6016                         ec.ConstantCheckState = last_const_check;
6017                 }
6018
6019         }
6020
6021         /// <summary>
6022         ///   Implements the unchecked expression
6023         /// </summary>
6024         public class UnCheckedExpr : Expression {
6025
6026                 public Expression Expr;
6027
6028                 public UnCheckedExpr (Expression e, Location l)
6029                 {
6030                         Expr = e;
6031                         loc = l;
6032                 }
6033
6034                 public override Expression DoResolve (EmitContext ec)
6035                 {
6036                         bool last_const_check = ec.ConstantCheckState;
6037
6038                         ec.ConstantCheckState = false;
6039                         Expr = Expr.Resolve (ec);
6040                         ec.ConstantCheckState = last_const_check;
6041
6042                         if (Expr == null)
6043                                 return null;
6044
6045                         if (Expr is Constant)
6046                                 return Expr;
6047
6048                         eclass = Expr.eclass;
6049                         type = Expr.Type;
6050                         return this;
6051                 }
6052
6053                 public override void Emit (EmitContext ec)
6054                 {
6055                         bool last_check = ec.CheckState;
6056                         bool last_const_check = ec.ConstantCheckState;
6057
6058                         ec.CheckState = false;
6059                         ec.ConstantCheckState = false;
6060                         Expr.Emit (ec);
6061                         ec.CheckState = last_check;
6062                         ec.ConstantCheckState = last_const_check;
6063                 }
6064
6065         }
6066
6067         /// <summary>
6068         ///   An Element Access expression.
6069         ///
6070         ///   During semantic analysis these are transformed into
6071         ///   IndexerAccess or ArrayAccess
6072         /// </summary>
6073         public class ElementAccess : Expression {
6074                 public ArrayList  Arguments;
6075                 public Expression Expr;
6076
6077                 public ElementAccess (Expression e, ArrayList e_list, Location l)
6078                 {
6079                         Expr = e;
6080
6081                         loc  = l;
6082
6083                         if (e_list == null)
6084                                 return;
6085
6086                         Arguments = new ArrayList ();
6087                         foreach (Expression tmp in e_list)
6088                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
6089
6090                 }
6091
6092                 bool CommonResolve (EmitContext ec)
6093                 {
6094                         Expr = Expr.Resolve (ec);
6095
6096                         if (Expr == null)
6097                                 return false;
6098
6099                         if (Arguments == null)
6100                                 return false;
6101
6102                         foreach (Argument a in Arguments){
6103                                 if (!a.Resolve (ec, loc))
6104                                         return false;
6105                         }
6106
6107                         return true;
6108                 }
6109
6110                 Expression MakePointerAccess ()
6111                 {
6112                         Type t = Expr.Type;
6113
6114                         if (t == TypeManager.void_ptr_type){
6115                                 Error (
6116                                         242,
6117                                         "The array index operation is not valid for void pointers");
6118                                 return null;
6119                         }
6120                         if (Arguments.Count != 1){
6121                                 Error (
6122                                         196,
6123                                         "A pointer must be indexed by a single value");
6124                                 return null;
6125                         }
6126                         Expression p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr,
6127                                                               t, loc);
6128                         return new Indirection (p, loc);
6129                 }
6130
6131                 public override Expression DoResolve (EmitContext ec)
6132                 {
6133                         if (!CommonResolve (ec))
6134                                 return null;
6135
6136                         //
6137                         // We perform some simple tests, and then to "split" the emit and store
6138                         // code we create an instance of a different class, and return that.
6139                         //
6140                         // I am experimenting with this pattern.
6141                         //
6142                         Type t = Expr.Type;
6143
6144                         if (t.IsArray)
6145                                 return (new ArrayAccess (this, loc)).Resolve (ec);
6146                         else if (t.IsPointer)
6147                                 return MakePointerAccess ();
6148                         else
6149                                 return (new IndexerAccess (this, loc)).Resolve (ec);
6150                 }
6151
6152                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6153                 {
6154                         if (!CommonResolve (ec))
6155                                 return null;
6156
6157                         Type t = Expr.Type;
6158                         if (t.IsArray)
6159                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
6160                         else if (t.IsPointer)
6161                                 return MakePointerAccess ();
6162                         else
6163                                 return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
6164                 }
6165
6166                 public override void Emit (EmitContext ec)
6167                 {
6168                         throw new Exception ("Should never be reached");
6169                 }
6170         }
6171
6172         /// <summary>
6173         ///   Implements array access
6174         /// </summary>
6175         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
6176                 //
6177                 // Points to our "data" repository
6178                 //
6179                 ElementAccess ea;
6180
6181                 LocalTemporary [] cached_locations;
6182
6183                 public ArrayAccess (ElementAccess ea_data, Location l)
6184                 {
6185                         ea = ea_data;
6186                         eclass = ExprClass.Variable;
6187                         loc = l;
6188                 }
6189
6190                 public override Expression DoResolve (EmitContext ec)
6191                 {
6192                         ExprClass eclass = ea.Expr.eclass;
6193
6194 #if false
6195                         // As long as the type is valid
6196                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
6197                               eclass == ExprClass.Value)) {
6198                                 ea.Expr.Error118 ("variable or value");
6199                                 return null;
6200                         }
6201 #endif
6202
6203                         Type t = ea.Expr.Type;
6204 /*
6205                         if (t == typeof (System.Object))
6206                         {
6207                                 // We can't resolve now, but we
6208                                 // have to try to access the array with a call
6209                                 // to LateIndexGet in the runtime
6210
6211                                 Expression lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexGet", Location.Null);
6212                                 Expression obj_type = Mono.MonoBASIC.Parser.DecomposeQI("System.Object", Location.Null);
6213                                 ArrayList adims = new ArrayList();
6214
6215                                 ArrayList ainit = new ArrayList();
6216                                 foreach (Argument a in ea.Arguments)
6217                                         ainit.Add ((Expression) a.Expr);
6218
6219                                 adims.Add ((Expression) new IntLiteral (ea.Arguments.Count));
6220
6221                                 Expression oace = new ArrayCreation (obj_type, adims, "", ainit, Location.Null);
6222
6223                                 ArrayList args = new ArrayList();
6224                                 args.Add (new Argument(ea.Expr, Argument.AType.Expression));
6225                                 args.Add (new Argument(oace, Argument.AType.Expression));
6226                                 args.Add (new Argument(NullLiteral.Null, Argument.AType.Expression));
6227
6228                                 Expression lig_call = new Invocation (lig_call_expr, args, Location.Null);
6229                                 lig_call = lig_call.Resolve(ec);
6230                                 return lig_call;
6231                         }
6232 */
6233                         if (t.GetArrayRank () != ea.Arguments.Count){
6234                                 ea.Error (22,
6235                                           "Incorrect number of indexes for array " +
6236                                           " expected: " + t.GetArrayRank () + " got: " +
6237                                           ea.Arguments.Count);
6238                                 return null;
6239                         }
6240                         type = TypeManager.TypeToCoreType (t.GetElementType ());
6241                         if (type.IsPointer && !ec.InUnsafe){
6242                                 UnsafeError (ea.Location);
6243                                 return null;
6244                         }
6245
6246                         foreach (Argument a in ea.Arguments){
6247                                 Type argtype = a.Type;
6248
6249                                 if (argtype == TypeManager.int32_type ||
6250                                     argtype == TypeManager.uint32_type ||
6251                                     argtype == TypeManager.int64_type ||
6252                                     argtype == TypeManager.uint64_type)
6253                                         continue;
6254
6255                                 //
6256                                 // Mhm.  This is strage, because the Argument.Type is not the same as
6257                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
6258                                 //
6259                                 // Wonder if I will run into trouble for this.
6260                                 //
6261                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
6262                                 if (a.Expr == null)
6263                                         return null;
6264                         }
6265
6266                         eclass = ExprClass.Variable;
6267
6268                         return this;
6269                 }
6270
6271                 /// <summary>
6272                 ///    Emits the right opcode to load an object of Type 't'
6273                 ///    from an array of T
6274                 /// </summary>
6275                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
6276                 {
6277                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
6278                                 ig.Emit (OpCodes.Ldelem_U1);
6279                         else if (type == TypeManager.sbyte_type)
6280                                 ig.Emit (OpCodes.Ldelem_I1);
6281                         else if (type == TypeManager.short_type)
6282                                 ig.Emit (OpCodes.Ldelem_I2);
6283                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
6284                                 ig.Emit (OpCodes.Ldelem_U2);
6285                         else if (type == TypeManager.int32_type)
6286                                 ig.Emit (OpCodes.Ldelem_I4);
6287                         else if (type == TypeManager.uint32_type)
6288                                 ig.Emit (OpCodes.Ldelem_U4);
6289                         else if (type == TypeManager.uint64_type)
6290                                 ig.Emit (OpCodes.Ldelem_I8);
6291                         else if (type == TypeManager.int64_type)
6292                                 ig.Emit (OpCodes.Ldelem_I8);
6293                         else if (type == TypeManager.float_type)
6294                                 ig.Emit (OpCodes.Ldelem_R4);
6295                         else if (type == TypeManager.double_type)
6296                                 ig.Emit (OpCodes.Ldelem_R8);
6297                         else if (type == TypeManager.intptr_type)
6298                                 ig.Emit (OpCodes.Ldelem_I);
6299                         else if (type.IsValueType){
6300                                 ig.Emit (OpCodes.Ldelema, type);
6301                                 ig.Emit (OpCodes.Ldobj, type);
6302                         } else
6303                                 ig.Emit (OpCodes.Ldelem_Ref);
6304                 }
6305
6306                 /// <summary>
6307                 ///    Emits the right opcode to store an object of Type 't'
6308                 ///    from an array of T.
6309                 /// </summary>
6310                 static public void EmitStoreOpcode (ILGenerator ig, Type t)
6311                 {
6312                         t = TypeManager.TypeToCoreType (t);
6313                         if (TypeManager.IsEnumType (t) && t != TypeManager.enum_type)
6314                                 t = TypeManager.EnumToUnderlying (t);
6315                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
6316                             t == TypeManager.bool_type)
6317                                 ig.Emit (OpCodes.Stelem_I1);
6318                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type || t == TypeManager.char_type)
6319                                 ig.Emit (OpCodes.Stelem_I2);
6320                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
6321                                 ig.Emit (OpCodes.Stelem_I4);
6322                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
6323                                 ig.Emit (OpCodes.Stelem_I8);
6324                         else if (t == TypeManager.float_type)
6325                                 ig.Emit (OpCodes.Stelem_R4);
6326                         else if (t == TypeManager.double_type)
6327                                 ig.Emit (OpCodes.Stelem_R8);
6328                         else if (t == TypeManager.intptr_type)
6329                                 ig.Emit (OpCodes.Stelem_I);
6330                         else if (t.IsValueType){
6331                                 ig.Emit (OpCodes.Stobj, t);
6332                         } else
6333                                 ig.Emit (OpCodes.Stelem_Ref);
6334                 }
6335
6336                 MethodInfo FetchGetMethod ()
6337                 {
6338                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6339                         int arg_count = ea.Arguments.Count;
6340                         Type [] args = new Type [arg_count];
6341                         MethodInfo get;
6342
6343                         for (int i = 0; i < arg_count; i++){
6344                                 //args [i++] = a.Type;
6345                                 args [i] = TypeManager.int32_type;
6346                         }
6347
6348                         get = mb.GetArrayMethod (
6349                                 ea.Expr.Type, "Get",
6350                                 CallingConventions.HasThis |
6351                                 CallingConventions.Standard,
6352                                 type, args);
6353                         return get;
6354                 }
6355
6356
6357                 MethodInfo FetchAddressMethod ()
6358                 {
6359                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6360                         int arg_count = ea.Arguments.Count;
6361                         Type [] args = new Type [arg_count];
6362                         MethodInfo address;
6363                         string ptr_type_name;
6364                         Type ret_type;
6365
6366                         ptr_type_name = type.FullName + "&";
6367                         ret_type = Type.GetType (ptr_type_name);
6368
6369                         //
6370                         // It is a type defined by the source code we are compiling
6371                         //
6372                         if (ret_type == null){
6373                                 ret_type = mb.GetType (ptr_type_name);
6374                         }
6375
6376                         for (int i = 0; i < arg_count; i++){
6377                                 //args [i++] = a.Type;
6378                                 args [i] = TypeManager.int32_type;
6379                         }
6380
6381                         address = mb.GetArrayMethod (
6382                                 ea.Expr.Type, "Address",
6383                                 CallingConventions.HasThis |
6384                                 CallingConventions.Standard,
6385                                 ret_type, args);
6386
6387                         return address;
6388                 }
6389
6390                 //
6391                 // Load the array arguments into the stack.
6392                 //
6393                 // If we have been requested to cache the values (cached_locations array
6394                 // initialized), then load the arguments the first time and store them
6395                 // in locals.  otherwise load from local variables.
6396                 //
6397                 void LoadArrayAndArguments (EmitContext ec)
6398                 {
6399                         ILGenerator ig = ec.ig;
6400
6401                         if (cached_locations == null){
6402                                 ea.Expr.Emit (ec);
6403                                 foreach (Argument a in ea.Arguments){
6404                                         Type argtype = a.Expr.Type;
6405
6406                                         a.Expr.Emit (ec);
6407
6408                                         if (argtype == TypeManager.int64_type)
6409                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6410                                         else if (argtype == TypeManager.uint64_type)
6411                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6412                                 }
6413                                 return;
6414                         }
6415
6416                         if (cached_locations [0] == null){
6417                                 cached_locations [0] = new LocalTemporary (ec, ea.Expr.Type);
6418                                 ea.Expr.Emit (ec);
6419                                 ig.Emit (OpCodes.Dup);
6420                                 cached_locations [0].Store (ec);
6421
6422                                 int j = 1;
6423
6424                                 foreach (Argument a in ea.Arguments){
6425                                         Type argtype = a.Expr.Type;
6426
6427                                         cached_locations [j] = new LocalTemporary (ec, TypeManager.intptr_type /* a.Expr.Type */);
6428                                         a.Expr.Emit (ec);
6429                                         if (argtype == TypeManager.int64_type)
6430                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6431                                         else if (argtype == TypeManager.uint64_type)
6432                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6433
6434                                         ig.Emit (OpCodes.Dup);
6435                                         cached_locations [j].Store (ec);
6436                                         j++;
6437                                 }
6438                                 return;
6439                         }
6440
6441                         foreach (LocalTemporary lt in cached_locations)
6442                                 lt.Emit (ec);
6443                 }
6444
6445                 public new void CacheTemporaries (EmitContext ec)
6446                 {
6447                         cached_locations = new LocalTemporary [ea.Arguments.Count + 1];
6448                 }
6449
6450                 public override void Emit (EmitContext ec)
6451                 {
6452                         int rank = ea.Expr.Type.GetArrayRank ();
6453                         ILGenerator ig = ec.ig;
6454
6455                         LoadArrayAndArguments (ec);
6456
6457                         if (rank == 1)
6458                                 EmitLoadOpcode (ig, type);
6459                         else {
6460                                 MethodInfo method;
6461
6462                                 method = FetchGetMethod ();
6463                                 ig.Emit (OpCodes.Call, method);
6464                         }
6465                 }
6466
6467                 public void EmitAssign (EmitContext ec, Expression source)
6468                 {
6469                         int rank = ea.Expr.Type.GetArrayRank ();
6470                         ILGenerator ig = ec.ig;
6471                         Type t = source.Type;
6472
6473                         LoadArrayAndArguments (ec);
6474
6475                         //
6476                         // The stobj opcode used by value types will need
6477                         // an address on the stack, not really an array/array
6478                         // pair
6479                         //
6480                         if (rank == 1){
6481                                 if (t == TypeManager.enum_type || t == TypeManager.decimal_type ||
6482                                     (t.IsSubclassOf (TypeManager.value_type) && !TypeManager.IsEnumType (t) && !TypeManager.IsBuiltinType (t)))
6483                                         ig.Emit (OpCodes.Ldelema, t);
6484                         }
6485
6486                         source.Emit (ec);
6487
6488                         if (rank == 1)
6489                                 EmitStoreOpcode (ig, t);
6490                         else {
6491                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
6492                                 int arg_count = ea.Arguments.Count;
6493                                 Type [] args = new Type [arg_count + 1];
6494                                 MethodInfo set;
6495
6496                                 for (int i = 0; i < arg_count; i++){
6497                                         //args [i++] = a.Type;
6498                                         args [i] = TypeManager.int32_type;
6499                                 }
6500
6501                                 args [arg_count] = type;
6502
6503                                 set = mb.GetArrayMethod (
6504                                         ea.Expr.Type, "Set",
6505                                         CallingConventions.HasThis |
6506                                         CallingConventions.Standard,
6507                                         TypeManager.void_type, args);
6508
6509                                 ig.Emit (OpCodes.Call, set);
6510                         }
6511                 }
6512
6513                 public void AddressOf (EmitContext ec, AddressOp mode)
6514                 {
6515                         int rank = ea.Expr.Type.GetArrayRank ();
6516                         ILGenerator ig = ec.ig;
6517
6518                         LoadArrayAndArguments (ec);
6519
6520                         if (rank == 1){
6521                                 ig.Emit (OpCodes.Ldelema, type);
6522                         } else {
6523                                 MethodInfo address = FetchAddressMethod ();
6524                                 ig.Emit (OpCodes.Call, address);
6525                         }
6526                 }
6527         }
6528
6529
6530         class Indexers {
6531                 public ArrayList getters, setters;
6532                 static Hashtable map;
6533
6534                 static Indexers ()
6535                 {
6536                         map = new Hashtable ();
6537                 }
6538
6539                 Indexers (MemberInfo [] mi)
6540                 {
6541                         foreach (PropertyInfo property in mi){
6542                                 MethodInfo get, set;
6543
6544                                 get = property.GetGetMethod (true);
6545                                 if (get != null){
6546                                         if (getters == null)
6547                                                 getters = new ArrayList ();
6548
6549                                         getters.Add (get);
6550                                 }
6551
6552                                 set = property.GetSetMethod (true);
6553                                 if (set != null){
6554                                         if (setters == null)
6555                                                 setters = new ArrayList ();
6556                                         setters.Add (set);
6557                                 }
6558                         }
6559                 }
6560
6561                 static private Indexers GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
6562                 {
6563                         Indexers ix = (Indexers) map [lookup_type];
6564
6565                         if (ix != null)
6566                                 return ix;
6567
6568                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
6569
6570                         MemberInfo [] mi = TypeManager.MemberLookup (
6571                                 caller_type, lookup_type, MemberTypes.Property,
6572                                 BindingFlags.Public | BindingFlags.Instance, p_name);
6573
6574                         if (mi == null || mi.Length == 0)
6575                                 return null;
6576
6577                         ix = new Indexers (mi);
6578                         map [lookup_type] = ix;
6579
6580                         return ix;
6581                 }
6582
6583                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
6584                 {
6585                         Indexers ix = (Indexers) map [lookup_type];
6586
6587                         if (ix != null)
6588                                 return ix;
6589
6590                         ix = GetIndexersForTypeOrInterface (caller_type, lookup_type);
6591                         if (ix != null)
6592                                 return ix;
6593
6594                         Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
6595                         if (ifaces != null) {
6596                                 foreach (Type itype in ifaces) {
6597                                         ix = GetIndexersForTypeOrInterface (caller_type, itype);
6598                                         if (ix != null)
6599                                                 return ix;
6600                                 }
6601                         }
6602
6603                         Report.Error (21, loc,
6604                                       "Type '" + TypeManager.MonoBASIC_Name (lookup_type) +
6605                                       "' does not have any indexers defined");
6606                         return null;
6607                 }
6608         }
6609
6610         /// <summary>
6611         ///   Expressions that represent an indexer call.
6612         /// </summary>
6613         public class IndexerAccess : Expression, IAssignMethod {
6614                 //
6615                 // Points to our "data" repository
6616                 //
6617                 MethodInfo get, set;
6618                 Indexers ilist;
6619                 ArrayList set_arguments;
6620                 bool is_base_indexer;
6621
6622                 protected Type indexer_type;
6623                 protected Type current_type;
6624                 protected Expression instance_expr;
6625                 protected ArrayList arguments;
6626
6627                 public IndexerAccess (ElementAccess ea, Location loc)
6628                         : this (ea.Expr, false, loc)
6629                 {
6630                         this.arguments = ea.Arguments;
6631                 }
6632
6633                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
6634                                          Location loc)
6635                 {
6636                         this.instance_expr = instance_expr;
6637                         this.is_base_indexer = is_base_indexer;
6638                         this.eclass = ExprClass.Value;
6639                         this.loc = loc;
6640                 }
6641
6642                 protected virtual bool CommonResolve (EmitContext ec)
6643                 {
6644                         indexer_type = instance_expr.Type;
6645                         current_type = ec.ContainerType;
6646
6647                         return true;
6648                 }
6649
6650                 public override Expression DoResolve (EmitContext ec)
6651                 {
6652                         if (!CommonResolve (ec))
6653                                 return null;
6654
6655                         //
6656                         // Step 1: Query for all 'Item' *properties*.  Notice
6657                         // that the actual methods are pointed from here.
6658                         //
6659                         // This is a group of properties, piles of them.
6660
6661                         if (ilist == null)
6662                                 ilist = Indexers.GetIndexersForType (
6663                                         current_type, indexer_type, loc);
6664
6665                         //
6666                         // Step 2: find the proper match
6667                         //
6668                         if (ilist != null && ilist.getters != null && ilist.getters.Count > 0)
6669                                 get = (MethodInfo) Invocation.OverloadResolve (
6670                                         ec, new MethodGroupExpr (ilist.getters, loc), arguments, loc);
6671
6672                         if (get == null){
6673                                 Error (154, "indexer can not be used in this context, because " +
6674                                        "it lacks a 'get' accessor");
6675                                 return null;
6676                         }
6677
6678                         type = get.ReturnType;
6679                         if (type.IsPointer && !ec.InUnsafe){
6680                                 UnsafeError (loc);
6681                                 return null;
6682                         }
6683
6684                         eclass = ExprClass.IndexerAccess;
6685                         return this;
6686                 }
6687
6688                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6689                 {
6690                         if (!CommonResolve (ec))
6691                                 return null;
6692
6693                         Type right_type = right_side.Type;
6694
6695                         if (ilist == null)
6696                                 ilist = Indexers.GetIndexersForType (
6697                                         current_type, indexer_type, loc);
6698
6699                         if (ilist != null && ilist.setters != null && ilist.setters.Count > 0){
6700                                 set_arguments = (ArrayList) arguments.Clone ();
6701                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
6702
6703                                 set = (MethodInfo) Invocation.OverloadResolve (
6704                                         ec, new MethodGroupExpr (ilist.setters, loc), set_arguments, loc);
6705                         }
6706
6707                         if (set == null){
6708                                 Error (200, "indexer X.this [" + TypeManager.MonoBASIC_Name (right_type) +
6709                                        "] lacks a 'set' accessor");
6710                                 return null;
6711                         }
6712
6713                         type = TypeManager.void_type;
6714                         eclass = ExprClass.IndexerAccess;
6715                         return this;
6716                 }
6717
6718                 public override void Emit (EmitContext ec)
6719                 {
6720                         Invocation.EmitCall (ec, false, false, instance_expr, get, arguments, loc);
6721                 }
6722
6723                 //
6724                 // source is ignored, because we already have a copy of it from the
6725                 // LValue resolution and we have already constructed a pre-cached
6726                 // version of the arguments (ea.set_arguments);
6727                 //
6728                 public void EmitAssign (EmitContext ec, Expression source)
6729                 {
6730                         Invocation.EmitCall (ec, false, false, instance_expr, set, set_arguments, loc);
6731                 }
6732         }
6733
6734         /// <summary>
6735         ///   The base operator for method names
6736         /// </summary>
6737         public class BaseAccess : Expression {
6738                 public string member;
6739
6740                 public BaseAccess (string member, Location l)
6741                 {
6742                         this.member = member;
6743                         loc = l;
6744                 }
6745
6746                 public override Expression DoResolve (EmitContext ec)
6747                 {
6748                         Expression member_lookup;
6749                         Type current_type = ec.ContainerType;
6750                         Type base_type = current_type.BaseType;
6751                         Expression e;
6752
6753                         if (ec.IsStatic){
6754                                 Error (1511, "Keyword MyBase is not allowed in static method");
6755                                 return null;
6756                         }
6757
6758                         if (member == "New")
6759                                 member = ".ctor";
6760
6761                         member_lookup = MemberLookup (ec, base_type, base_type, member,
6762                                                       AllMemberTypes, AllBindingFlags, loc);
6763
6764                         if (member_lookup == null) {
6765                                 Error (117,
6766                                               TypeManager.MonoBASIC_Name (base_type) + " does not " +
6767                                               "contain a definition for '" + member + "'");
6768                                 return null;
6769                         }
6770
6771                         Expression left;
6772
6773                         if (ec.IsStatic)
6774                                 left = new TypeExpr (base_type, loc);
6775                         else
6776                                 left = ec.This;
6777
6778                         e = MemberAccess.ResolveMemberAccess (ec, member_lookup, left, loc, null);
6779
6780                         if (e is PropertyExpr){
6781                                 PropertyExpr pe = (PropertyExpr) e;
6782
6783                                 pe.IsBase = true;
6784                         }
6785
6786                         return e;
6787                 }
6788
6789                 public override void Emit (EmitContext ec)
6790                 {
6791                         throw new Exception ("Should never be called");
6792                 }
6793         }
6794
6795         /// <summary>
6796         ///   The base indexer operator
6797         /// </summary>
6798         public class BaseIndexerAccess : IndexerAccess {
6799                 public BaseIndexerAccess (ArrayList args, Location loc)
6800                         : base (null, true, loc)
6801                 {
6802                         arguments = new ArrayList ();
6803                         foreach (Expression tmp in args)
6804                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
6805                 }
6806
6807                 protected override bool CommonResolve (EmitContext ec)
6808                 {
6809                         instance_expr = ec.This;
6810
6811                         current_type = ec.ContainerType.BaseType;
6812                         indexer_type = current_type;
6813
6814                         foreach (Argument a in arguments){
6815                                 if (!a.Resolve (ec, loc))
6816                                         return false;
6817                         }
6818
6819                         return true;
6820                 }
6821         }
6822
6823         /// <summary>
6824         ///   This class exists solely to pass the Type around and to be a dummy
6825         ///   that can be passed to the conversion functions (this is used by
6826         ///   foreach implementation to typecast the object return value from
6827         ///   get_Current into the proper type.  All code has been generated and
6828         ///   we only care about the side effect conversions to be performed
6829         ///
6830         ///   This is also now used as a placeholder where a no-action expression
6831         ///   is needed (the 'New' class).
6832         /// </summary>
6833         public class EmptyExpression : Expression {
6834                 public EmptyExpression ()
6835                 {
6836                         type = TypeManager.object_type;
6837                         eclass = ExprClass.Value;
6838                         loc = Location.Null;
6839                 }
6840
6841                 public EmptyExpression (Type t)
6842                 {
6843                         type = t;
6844                         eclass = ExprClass.Value;
6845                         loc = Location.Null;
6846                 }
6847
6848                 public override Expression DoResolve (EmitContext ec)
6849                 {
6850                         return this;
6851                 }
6852
6853                 public override void Emit (EmitContext ec)
6854                 {
6855                         // nothing, as we only exist to not do anything.
6856                 }
6857
6858                 //
6859                 // This is just because we might want to reuse this bad boy
6860                 // instead of creating gazillions of EmptyExpressions.
6861                 // (CanConvertImplicit uses it)
6862                 //
6863                 public void SetType (Type t)
6864                 {
6865                         type = t;
6866                 }
6867         }
6868
6869         public class UserCast : Expression {
6870                 MethodBase method;
6871                 Expression source;
6872
6873                 public UserCast (MethodInfo method, Expression source, Location l)
6874                 {
6875                         this.method = method;
6876                         this.source = source;
6877                         type = method.ReturnType;
6878                         eclass = ExprClass.Value;
6879                         loc = l;
6880                 }
6881
6882                 public override Expression DoResolve (EmitContext ec)
6883                 {
6884                         //
6885                         // We are born fully resolved
6886                         //
6887                         return this;
6888                 }
6889
6890                 public override void Emit (EmitContext ec)
6891                 {
6892                         ILGenerator ig = ec.ig;
6893
6894                         source.Emit (ec);
6895
6896                         if (method is MethodInfo)
6897                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
6898                         else
6899                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
6900
6901                 }
6902         }
6903
6904         // <summary>
6905         //   This class is used to "construct" the type during a typecast
6906         //   operation.  Since the Type.GetType class in .NET can parse
6907         //   the type specification, we just use this to construct the type
6908         //   one bit at a time.
6909         // </summary>
6910         public class ComposedCast : Expression, ITypeExpression {
6911                 Expression left;
6912                 string dim;
6913
6914                 public ComposedCast (Expression left, string dim, Location l)
6915                 {
6916                         this.left = left;
6917                         this.dim = dim;
6918                         loc = l;
6919                 }
6920
6921                 public Expression DoResolveType (EmitContext ec)
6922                 {
6923                         Type ltype = ec.DeclSpace.ResolveType (left, false, loc);
6924                         if (ltype == null)
6925                                 return null;
6926
6927                         //
6928                         // ltype.Fullname is already fully qualified, so we can skip
6929                         // a lot of probes, and go directly to TypeManager.LookupType
6930                         //
6931                         string cname = ltype.FullName + dim;
6932                         type = TypeManager.LookupTypeDirect (cname);
6933                         if (type == null){
6934                                 //
6935                                 // For arrays of enumerations we are having a problem
6936                                 // with the direct lookup.  Need to investigate.
6937                                 //
6938                                 // For now, fall back to the full lookup in that case.
6939                                 //
6940                                 type = RootContext.LookupType (
6941                                         ec.DeclSpace, cname, false, loc);
6942
6943                                 if (type == null)
6944                                         return null;
6945                         }
6946
6947                         if (!ec.ResolvingTypeTree){
6948                                 //
6949                                 // If the above flag is set, this is being invoked from the ResolveType function.
6950                                 // Upper layers take care of the type validity in this context.
6951                                 //
6952                         if (!ec.InUnsafe && type.IsPointer){
6953                                 UnsafeError (loc);
6954                                 return null;
6955                         }
6956                         }
6957
6958                         eclass = ExprClass.Type;
6959                         return this;
6960                 }
6961
6962                 public override Expression DoResolve (EmitContext ec)
6963                 {
6964                         return DoResolveType (ec);
6965                 }
6966
6967                 public override void Emit (EmitContext ec)
6968                 {
6969                         throw new Exception ("This should never be called");
6970                 }
6971
6972                 public override string ToString ()
6973                 {
6974                         return left + dim;
6975                 }
6976         }
6977
6978         //
6979         // This class is used to represent the address of an array, used
6980         // only by the Fixed statement, this is like the C "&a [0]" construct.
6981         //
6982         public class ArrayPtr : Expression {
6983                 Expression array;
6984
6985                 public ArrayPtr (Expression array, Location l)
6986                 {
6987                         Type array_type = array.Type.GetElementType ();
6988
6989                         this.array = array;
6990
6991                         string array_ptr_type_name = array_type.FullName + "*";
6992
6993                         type = Type.GetType (array_ptr_type_name);
6994                         if (type == null){
6995                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
6996
6997                                 type = mb.GetType (array_ptr_type_name);
6998                         }
6999
7000                         eclass = ExprClass.Value;
7001                         loc = l;
7002                 }
7003
7004                 public override void Emit (EmitContext ec)
7005                 {
7006                         ILGenerator ig = ec.ig;
7007
7008                         array.Emit (ec);
7009                         IntLiteral.EmitInt (ig, 0);
7010                         ig.Emit (OpCodes.Ldelema, array.Type.GetElementType ());
7011                 }
7012
7013                 public override Expression DoResolve (EmitContext ec)
7014                 {
7015                         //
7016                         // We are born fully resolved
7017                         //
7018                         return this;
7019                 }
7020         }
7021
7022         //
7023         // Used by the fixed statement
7024         //
7025         public class StringPtr : Expression {
7026                 LocalBuilder b;
7027
7028                 public StringPtr (LocalBuilder b, Location l)
7029                 {
7030                         this.b = b;
7031                         eclass = ExprClass.Value;
7032                         type = TypeManager.char_ptr_type;
7033                         loc = l;
7034                 }
7035
7036                 public override Expression DoResolve (EmitContext ec)
7037                 {
7038                         // This should never be invoked, we are born in fully
7039                         // initialized state.
7040
7041                         return this;
7042                 }
7043
7044                 public override void Emit (EmitContext ec)
7045                 {
7046                         ILGenerator ig = ec.ig;
7047
7048                         ig.Emit (OpCodes.Ldloc, b);
7049                         ig.Emit (OpCodes.Conv_I);
7050                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
7051                         ig.Emit (OpCodes.Add);
7052                 }
7053         }
7054
7055         //
7056         // Implements the 'stackalloc' keyword
7057         //
7058         public class StackAlloc : Expression {
7059                 Type otype;
7060                 Expression t;
7061                 Expression count;
7062
7063                 public StackAlloc (Expression type, Expression count, Location l)
7064                 {
7065                         t = type;
7066                         this.count = count;
7067                         loc = l;
7068                 }
7069
7070                 public override Expression DoResolve (EmitContext ec)
7071                 {
7072                         count = count.Resolve (ec);
7073                         if (count == null)
7074                                 return null;
7075
7076                         if (count.Type != TypeManager.int32_type){
7077                                 count = ConvertImplicitRequired (ec, count, TypeManager.int32_type, loc);
7078                                 if (count == null)
7079                                         return null;
7080                         }
7081
7082                         if (ec.InCatch || ec.InFinally){
7083                                 Error (255,
7084                                               "stackalloc can not be used in a catch or finally block");
7085                                 return null;
7086                         }
7087
7088                         otype = ec.DeclSpace.ResolveType (t, false, loc);
7089
7090                         if (otype == null)
7091                                 return null;
7092
7093                         if (!TypeManager.VerifyUnManaged (otype, loc))
7094                                 return null;
7095
7096                         string ptr_name = otype.FullName + "*";
7097                         type = Type.GetType (ptr_name);
7098                         if (type == null){
7099                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
7100
7101                                 type = mb.GetType (ptr_name);
7102                         }
7103                         eclass = ExprClass.Value;
7104
7105                         return this;
7106                 }
7107
7108                 public override void Emit (EmitContext ec)
7109                 {
7110                         int size = GetTypeSize (otype);
7111                         ILGenerator ig = ec.ig;
7112
7113                         if (size == 0)
7114                                 ig.Emit (OpCodes.Sizeof, otype);
7115                         else
7116                                 IntConstant.EmitInt (ig, size);
7117                         count.Emit (ec);
7118                         ig.Emit (OpCodes.Mul);
7119                         ig.Emit (OpCodes.Localloc);
7120                 }
7121         }
7122 }