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                 bool runtime_cast;
1165
1166                 public Cast (Expression cast_type, Expression expr, Location loc)
1167                 {
1168                         this.target_type = cast_type;
1169                         this.expr = expr;
1170                         this.loc = loc;
1171                         runtime_cast = false;
1172                 }
1173
1174                 public Expression TargetType {
1175                         get {
1176                                 return target_type;
1177                         }
1178                 }
1179
1180                 public Expression Expr {
1181                         get {
1182                                 return expr;
1183                         }
1184                         set {
1185                                 expr = value;
1186                         }
1187                 }
1188
1189                 public bool IsRuntimeCast
1190                 {
1191                         get {
1192                                 return runtime_cast;
1193                         }
1194                         set{
1195                                 runtime_cast = value;
1196                         }
1197                 }
1198
1199                 /// <summary>
1200                 ///   Attempts to do a compile-time folding of a constant cast.
1201                 /// </summary>
1202                 Expression TryReduce (EmitContext ec, Type target_type)
1203                 {
1204                         if (expr is ByteConstant){
1205                                 byte v = ((ByteConstant) expr).Value;
1206
1207                                 if (target_type == TypeManager.sbyte_type)
1208                                         return new SByteConstant ((sbyte) v);
1209                                 if (target_type == TypeManager.short_type)
1210                                         return new ShortConstant ((short) v);
1211                                 if (target_type == TypeManager.ushort_type)
1212                                         return new UShortConstant ((ushort) v);
1213                                 if (target_type == TypeManager.int32_type)
1214                                         return new IntConstant ((int) v);
1215                                 if (target_type == TypeManager.uint32_type)
1216                                         return new UIntConstant ((uint) v);
1217                                 if (target_type == TypeManager.int64_type)
1218                                         return new LongConstant ((long) v);
1219                                 if (target_type == TypeManager.uint64_type)
1220                                         return new ULongConstant ((ulong) v);
1221                                 if (target_type == TypeManager.float_type)
1222                                         return new FloatConstant ((float) v);
1223                                 if (target_type == TypeManager.double_type)
1224                                         return new DoubleConstant ((double) v);
1225                                 if (target_type == TypeManager.char_type)
1226                                         return new CharConstant ((char) v);
1227                                 if (target_type == TypeManager.decimal_type)
1228                                         return new DecimalConstant ((decimal) v);
1229                         }
1230                         if (expr is SByteConstant){
1231                                 sbyte v = ((SByteConstant) expr).Value;
1232
1233                                 if (target_type == TypeManager.byte_type)
1234                                         return new ByteConstant ((byte) v);
1235                                 if (target_type == TypeManager.short_type)
1236                                         return new ShortConstant ((short) v);
1237                                 if (target_type == TypeManager.ushort_type)
1238                                         return new UShortConstant ((ushort) v);
1239                                 if (target_type == TypeManager.int32_type)
1240                                         return new IntConstant ((int) v);
1241                                 if (target_type == TypeManager.uint32_type)
1242                                         return new UIntConstant ((uint) v);
1243                                 if (target_type == TypeManager.int64_type)
1244                                         return new LongConstant ((long) v);
1245                                 if (target_type == TypeManager.uint64_type)
1246                                         return new ULongConstant ((ulong) v);
1247                                 if (target_type == TypeManager.float_type)
1248                                         return new FloatConstant ((float) v);
1249                                 if (target_type == TypeManager.double_type)
1250                                         return new DoubleConstant ((double) v);
1251                                 if (target_type == TypeManager.char_type)
1252                                         return new CharConstant ((char) v);
1253                                 if (target_type == TypeManager.decimal_type)
1254                                         return new DecimalConstant ((decimal) v);
1255                         }
1256                         if (expr is ShortConstant){
1257                                 short v = ((ShortConstant) expr).Value;
1258
1259                                 if (target_type == TypeManager.byte_type)
1260                                         return new ByteConstant ((byte) v);
1261                                 if (target_type == TypeManager.sbyte_type)
1262                                         return new SByteConstant ((sbyte) v);
1263                                 if (target_type == TypeManager.ushort_type)
1264                                         return new UShortConstant ((ushort) v);
1265                                 if (target_type == TypeManager.int32_type)
1266                                         return new IntConstant ((int) v);
1267                                 if (target_type == TypeManager.uint32_type)
1268                                         return new UIntConstant ((uint) v);
1269                                 if (target_type == TypeManager.int64_type)
1270                                         return new LongConstant ((long) v);
1271                                 if (target_type == TypeManager.uint64_type)
1272                                         return new ULongConstant ((ulong) v);
1273                                 if (target_type == TypeManager.float_type)
1274                                         return new FloatConstant ((float) v);
1275                                 if (target_type == TypeManager.double_type)
1276                                         return new DoubleConstant ((double) v);
1277                                 if (target_type == TypeManager.char_type)
1278                                         return new CharConstant ((char) v);
1279                                 if (target_type == TypeManager.decimal_type)
1280                                         return new DecimalConstant ((decimal) v);
1281                         }
1282                         if (expr is UShortConstant){
1283                                 ushort v = ((UShortConstant) expr).Value;
1284
1285                                 if (target_type == TypeManager.byte_type)
1286                                         return new ByteConstant ((byte) v);
1287                                 if (target_type == TypeManager.sbyte_type)
1288                                         return new SByteConstant ((sbyte) v);
1289                                 if (target_type == TypeManager.short_type)
1290                                         return new ShortConstant ((short) v);
1291                                 if (target_type == TypeManager.int32_type)
1292                                         return new IntConstant ((int) v);
1293                                 if (target_type == TypeManager.uint32_type)
1294                                         return new UIntConstant ((uint) v);
1295                                 if (target_type == TypeManager.int64_type)
1296                                         return new LongConstant ((long) v);
1297                                 if (target_type == TypeManager.uint64_type)
1298                                         return new ULongConstant ((ulong) v);
1299                                 if (target_type == TypeManager.float_type)
1300                                         return new FloatConstant ((float) v);
1301                                 if (target_type == TypeManager.double_type)
1302                                         return new DoubleConstant ((double) v);
1303                                 if (target_type == TypeManager.char_type)
1304                                         return new CharConstant ((char) v);
1305                                 if (target_type == TypeManager.decimal_type)
1306                                         return new DecimalConstant ((decimal) v);
1307                         }
1308                         if (expr is IntConstant){
1309                                 int v = ((IntConstant) expr).Value;
1310
1311                                 if (target_type == TypeManager.byte_type)
1312                                         return new ByteConstant ((byte) v);
1313                                 if (target_type == TypeManager.sbyte_type)
1314                                         return new SByteConstant ((sbyte) v);
1315                                 if (target_type == TypeManager.short_type)
1316                                         return new ShortConstant ((short) v);
1317                                 if (target_type == TypeManager.ushort_type)
1318                                         return new UShortConstant ((ushort) v);
1319                                 if (target_type == TypeManager.uint32_type)
1320                                         return new UIntConstant ((uint) v);
1321                                 if (target_type == TypeManager.int64_type)
1322                                         return new LongConstant ((long) v);
1323                                 if (target_type == TypeManager.uint64_type)
1324                                         return new ULongConstant ((ulong) v);
1325                                 if (target_type == TypeManager.float_type)
1326                                         return new FloatConstant ((float) v);
1327                                 if (target_type == TypeManager.double_type)
1328                                         return new DoubleConstant ((double) v);
1329                                 if (target_type == TypeManager.char_type)
1330                                         return new CharConstant ((char) v);
1331                                 if (target_type == TypeManager.decimal_type)
1332                                         return new DecimalConstant ((decimal) v);
1333                         }
1334                         if (expr is UIntConstant){
1335                                 uint v = ((UIntConstant) expr).Value;
1336
1337                                 if (target_type == TypeManager.byte_type)
1338                                         return new ByteConstant ((byte) v);
1339                                 if (target_type == TypeManager.sbyte_type)
1340                                         return new SByteConstant ((sbyte) v);
1341                                 if (target_type == TypeManager.short_type)
1342                                         return new ShortConstant ((short) v);
1343                                 if (target_type == TypeManager.ushort_type)
1344                                         return new UShortConstant ((ushort) v);
1345                                 if (target_type == TypeManager.int32_type)
1346                                         return new IntConstant ((int) v);
1347                                 if (target_type == TypeManager.int64_type)
1348                                         return new LongConstant ((long) v);
1349                                 if (target_type == TypeManager.uint64_type)
1350                                         return new ULongConstant ((ulong) v);
1351                                 if (target_type == TypeManager.float_type)
1352                                         return new FloatConstant ((float) v);
1353                                 if (target_type == TypeManager.double_type)
1354                                         return new DoubleConstant ((double) v);
1355                                 if (target_type == TypeManager.char_type)
1356                                         return new CharConstant ((char) v);
1357                                 if (target_type == TypeManager.decimal_type)
1358                                         return new DecimalConstant ((decimal) v);
1359                         }
1360                         if (expr is LongConstant){
1361                                 long v = ((LongConstant) expr).Value;
1362
1363                                 if (target_type == TypeManager.byte_type)
1364                                         return new ByteConstant ((byte) v);
1365                                 if (target_type == TypeManager.sbyte_type)
1366                                         return new SByteConstant ((sbyte) v);
1367                                 if (target_type == TypeManager.short_type)
1368                                         return new ShortConstant ((short) v);
1369                                 if (target_type == TypeManager.ushort_type)
1370                                         return new UShortConstant ((ushort) v);
1371                                 if (target_type == TypeManager.int32_type)
1372                                         return new IntConstant ((int) v);
1373                                 if (target_type == TypeManager.uint32_type)
1374                                         return new UIntConstant ((uint) v);
1375                                 if (target_type == TypeManager.uint64_type)
1376                                         return new ULongConstant ((ulong) v);
1377                                 if (target_type == TypeManager.float_type)
1378                                         return new FloatConstant ((float) v);
1379                                 if (target_type == TypeManager.double_type)
1380                                         return new DoubleConstant ((double) v);
1381                                 if (target_type == TypeManager.char_type)
1382                                         return new CharConstant ((char) v);
1383                                 if (target_type == TypeManager.decimal_type)
1384                                         return new DecimalConstant ((decimal) v);
1385                         }
1386                         if (expr is ULongConstant){
1387                                 ulong v = ((ULongConstant) expr).Value;
1388
1389                                 if (target_type == TypeManager.byte_type)
1390                                         return new ByteConstant ((byte) v);
1391                                 if (target_type == TypeManager.sbyte_type)
1392                                         return new SByteConstant ((sbyte) v);
1393                                 if (target_type == TypeManager.short_type)
1394                                         return new ShortConstant ((short) v);
1395                                 if (target_type == TypeManager.ushort_type)
1396                                         return new UShortConstant ((ushort) v);
1397                                 if (target_type == TypeManager.int32_type)
1398                                         return new IntConstant ((int) v);
1399                                 if (target_type == TypeManager.uint32_type)
1400                                         return new UIntConstant ((uint) v);
1401                                 if (target_type == TypeManager.int64_type)
1402                                         return new LongConstant ((long) v);
1403                                 if (target_type == TypeManager.float_type)
1404                                         return new FloatConstant ((float) v);
1405                                 if (target_type == TypeManager.double_type)
1406                                         return new DoubleConstant ((double) v);
1407                                 if (target_type == TypeManager.char_type)
1408                                         return new CharConstant ((char) v);
1409                                 if (target_type == TypeManager.decimal_type)
1410                                         return new DecimalConstant ((decimal) v);
1411                         }
1412                         if (expr is FloatConstant){
1413                                 float v = ((FloatConstant) expr).Value;
1414
1415                                 if (target_type == TypeManager.byte_type)
1416                                         return new ByteConstant ((byte) v);
1417                                 if (target_type == TypeManager.sbyte_type)
1418                                         return new SByteConstant ((sbyte) v);
1419                                 if (target_type == TypeManager.short_type)
1420                                         return new ShortConstant ((short) v);
1421                                 if (target_type == TypeManager.ushort_type)
1422                                         return new UShortConstant ((ushort) v);
1423                                 if (target_type == TypeManager.int32_type)
1424                                         return new IntConstant ((int) v);
1425                                 if (target_type == TypeManager.uint32_type)
1426                                         return new UIntConstant ((uint) v);
1427                                 if (target_type == TypeManager.int64_type)
1428                                         return new LongConstant ((long) v);
1429                                 if (target_type == TypeManager.uint64_type)
1430                                         return new ULongConstant ((ulong) v);
1431                                 if (target_type == TypeManager.double_type)
1432                                         return new DoubleConstant ((double) v);
1433                                 if (target_type == TypeManager.char_type)
1434                                         return new CharConstant ((char) v);
1435                                 if (target_type == TypeManager.decimal_type)
1436                                         return new DecimalConstant ((decimal) v);
1437                         }
1438                         if (expr is DoubleConstant){
1439                                 double v = ((DoubleConstant) expr).Value;
1440
1441                                 if (target_type == TypeManager.byte_type)
1442                                         return new ByteConstant ((byte) v);
1443                                 if (target_type == TypeManager.sbyte_type)
1444                                         return new SByteConstant ((sbyte) v);
1445                                 if (target_type == TypeManager.short_type)
1446                                         return new ShortConstant ((short) v);
1447                                 if (target_type == TypeManager.ushort_type)
1448                                         return new UShortConstant ((ushort) v);
1449                                 if (target_type == TypeManager.int32_type)
1450                                         return new IntConstant ((int) v);
1451                                 if (target_type == TypeManager.uint32_type)
1452                                         return new UIntConstant ((uint) v);
1453                                 if (target_type == TypeManager.int64_type)
1454                                         return new LongConstant ((long) v);
1455                                 if (target_type == TypeManager.uint64_type)
1456                                         return new ULongConstant ((ulong) v);
1457                                 if (target_type == TypeManager.float_type)
1458                                         return new FloatConstant ((float) v);
1459                                 if (target_type == TypeManager.char_type)
1460                                         return new CharConstant ((char) v);
1461                                 if (target_type == TypeManager.decimal_type)
1462                                         return new DecimalConstant ((decimal) v);
1463                         }
1464
1465                         return null;
1466                 }
1467
1468                 public override Expression DoResolve (EmitContext ec)
1469                 {
1470                         expr = expr.Resolve (ec);
1471                         if (expr == null)
1472                                 return null;
1473
1474                         int errors = Report.Errors;
1475
1476                         type = ec.DeclSpace.ResolveType (target_type, false, Location);
1477
1478                         if (type == null)
1479                                 return null;
1480
1481                         eclass = ExprClass.Value;
1482
1483                         if (expr is Constant){
1484                                 Expression e = TryReduce (ec, type);
1485
1486                                 if (e != null)
1487                                         return e;
1488                         }
1489
1490                         expr = ConvertExplicit (ec, expr, type, runtime_cast, loc);
1491                         return expr;
1492                 }
1493
1494                 public override void Emit (EmitContext ec)
1495                 {
1496                         //
1497                         // This one will never happen
1498                         //
1499                         throw new Exception ("Should not happen");
1500                 }
1501         }
1502
1503         /// <summary>
1504         ///   Binary operators
1505         /// </summary>
1506         public class Binary : Expression {
1507                 public enum Operator : byte {
1508                         Multiply, Division, Modulus,
1509                         Addition, Subtraction,
1510                         LeftShift, RightShift,
1511                         LessThan, GreaterThan, LessThanOrEqual, GreaterThanOrEqual,
1512                         Equality, Inequality,
1513                         BitwiseAnd,
1514                         ExclusiveOr,
1515                         BitwiseOr,
1516                         LogicalAnd,
1517                         LogicalOr,
1518                         TOP
1519                 }
1520
1521                 Operator oper;
1522                 Expression left, right;
1523
1524                 //
1525                 // After resolution, method might contain the operator overload
1526                 // method.
1527                 //
1528                 protected MethodBase method;
1529                 ArrayList  Arguments;
1530
1531                 bool DelegateOperation;
1532
1533                 // This must be kept in sync with Operator!!!
1534                 static string [] oper_names;
1535
1536                 static Binary ()
1537                 {
1538                         oper_names = new string [(int) Operator.TOP];
1539
1540                         oper_names [(int) Operator.Multiply] = "op_Multiply";
1541                         oper_names [(int) Operator.Division] = "op_Division";
1542                         oper_names [(int) Operator.Modulus] = "op_Modulus";
1543                         oper_names [(int) Operator.Addition] = "op_Addition";
1544                         oper_names [(int) Operator.Subtraction] = "op_Subtraction";
1545                         oper_names [(int) Operator.LeftShift] = "op_LeftShift";
1546                         oper_names [(int) Operator.RightShift] = "op_RightShift";
1547                         oper_names [(int) Operator.LessThan] = "op_LessThan";
1548                         oper_names [(int) Operator.GreaterThan] = "op_GreaterThan";
1549                         oper_names [(int) Operator.LessThanOrEqual] = "op_LessThanOrEqual";
1550                         oper_names [(int) Operator.GreaterThanOrEqual] = "op_GreaterThanOrEqual";
1551                         oper_names [(int) Operator.Equality] = "op_Equality";
1552                         oper_names [(int) Operator.Inequality] = "op_Inequality";
1553                         oper_names [(int) Operator.BitwiseAnd] = "op_BitwiseAnd";
1554                         oper_names [(int) Operator.BitwiseOr] = "op_BitwiseOr";
1555                         oper_names [(int) Operator.ExclusiveOr] = "op_ExclusiveOr";
1556                         oper_names [(int) Operator.LogicalOr] = "op_LogicalOr";
1557                         oper_names [(int) Operator.LogicalAnd] = "op_LogicalAnd";
1558                 }
1559
1560                 public Binary (Operator oper, Expression left, Expression right, Location loc)
1561                 {
1562                         this.oper = oper;
1563                         this.left = left;
1564                         this.right = right;
1565                         this.loc = loc;
1566                 }
1567
1568                 public Operator Oper {
1569                         get {
1570                                 return oper;
1571                         }
1572                         set {
1573                                 oper = value;
1574                         }
1575                 }
1576
1577                 public Expression Left {
1578                         get {
1579                                 return left;
1580                         }
1581                         set {
1582                                 left = value;
1583                         }
1584                 }
1585
1586                 public Expression Right {
1587                         get {
1588                                 return right;
1589                         }
1590                         set {
1591                                 right = value;
1592                         }
1593                 }
1594
1595
1596                 /// <summary>
1597                 ///   Returns a stringified representation of the Operator
1598                 /// </summary>
1599                 static string OperName (Operator oper)
1600                 {
1601                         switch (oper){
1602                         case Operator.Multiply:
1603                                 return "*";
1604                         case Operator.Division:
1605                                 return "/";
1606                         case Operator.Modulus:
1607                                 return "%";
1608                         case Operator.Addition:
1609                                 return "+";
1610                         case Operator.Subtraction:
1611                                 return "-";
1612                         case Operator.LeftShift:
1613                                 return "<<";
1614                         case Operator.RightShift:
1615                                 return ">>";
1616                         case Operator.LessThan:
1617                                 return "<";
1618                         case Operator.GreaterThan:
1619                                 return ">";
1620                         case Operator.LessThanOrEqual:
1621                                 return "<=";
1622                         case Operator.GreaterThanOrEqual:
1623                                 return ">=";
1624                         case Operator.Equality:
1625                                 return "==";
1626                         case Operator.Inequality:
1627                                 return "!=";
1628                         case Operator.BitwiseAnd:
1629                                 return "&";
1630                         case Operator.BitwiseOr:
1631                                 return "|";
1632                         case Operator.ExclusiveOr:
1633                                 return "^";
1634                         case Operator.LogicalOr:
1635                                 return "||";
1636                         case Operator.LogicalAnd:
1637                                 return "&&";
1638                         }
1639
1640                         return oper.ToString ();
1641                 }
1642
1643                 public override string ToString ()
1644                 {
1645                         return "operator " + OperName (oper) + "(" + left.ToString () + ", " +
1646                                 right.ToString () + ")";
1647                 }
1648
1649                 Expression ForceConversion (EmitContext ec, Expression expr, Type target_type)
1650                 {
1651                         if (expr.Type == target_type)
1652                                 return expr;
1653
1654                         return ConvertImplicit (ec, expr, target_type, Location.Null);
1655                 }
1656
1657                 public static void Error_OperatorAmbiguous (Location loc, Operator oper, Type l, Type r)
1658                 {
1659                         Report.Error (
1660                                 34, loc, "Operator '" + OperName (oper)
1661                                 + "' is ambiguous on operands of type '"
1662                                 + TypeManager.MonoBASIC_Name (l) + "' "
1663                                 + "and '" + TypeManager.MonoBASIC_Name (r)
1664                                 + "'");
1665                 }
1666
1667                 //
1668                 // Note that handling the case l == Decimal || r == Decimal
1669                 // is taken care of by the Step 1 Operator Overload resolution.
1670                 //
1671                 bool DoNumericPromotions (EmitContext ec, Type l, Type r)
1672                 {
1673                         if (l == TypeManager.double_type || r == TypeManager.double_type){
1674                                 //
1675                                 // If either operand is of type double, the other operand is
1676                                 // conveted to type double.
1677                                 //
1678                                 if (r != TypeManager.double_type)
1679                                         right = ConvertImplicit (ec, right, TypeManager.double_type, loc);
1680                                 if (l != TypeManager.double_type)
1681                                         left = ConvertImplicit (ec, left, TypeManager.double_type, loc);
1682
1683                                 type = TypeManager.double_type;
1684                         } else if (l == TypeManager.float_type || r == TypeManager.float_type){
1685                                 //
1686                                 // if either operand is of type float, the other operand is
1687                                 // converted to type float.
1688                                 //
1689                                 if (r != TypeManager.double_type)
1690                                         right = ConvertImplicit (ec, right, TypeManager.float_type, loc);
1691                                 if (l != TypeManager.double_type)
1692                                         left = ConvertImplicit (ec, left, TypeManager.float_type, loc);
1693                                 type = TypeManager.float_type;
1694                         } else if (l == TypeManager.uint64_type || r == TypeManager.uint64_type){
1695                                 Expression e;
1696                                 Type other;
1697                                 //
1698                                 // If either operand is of type ulong, the other operand is
1699                                 // converted to type ulong.  or an error ocurrs if the other
1700                                 // operand is of type sbyte, short, int or long
1701                                 //
1702                                 if (l == TypeManager.uint64_type){
1703                                         if (r != TypeManager.uint64_type){
1704                                                 if (right is IntConstant){
1705                                                         IntConstant ic = (IntConstant) right;
1706
1707                                                         e = TryImplicitIntConversion (l, ic);
1708                                                         if (e != null)
1709                                                                 right = e;
1710                                                 } else if (right is LongConstant){
1711                                                         long ll = ((LongConstant) right).Value;
1712
1713                                                         if (ll > 0)
1714                                                                 right = new ULongConstant ((ulong) ll);
1715                                                 } else {
1716                                                         e = ImplicitNumericConversion (ec, right, l, loc);
1717                                                         if (e != null)
1718                                                                 right = e;
1719                                                 }
1720                                         }
1721                                         other = right.Type;
1722                                 } else {
1723                                         if (left is IntConstant){
1724                                                 e = TryImplicitIntConversion (r, (IntConstant) left);
1725                                                 if (e != null)
1726                                                         left = e;
1727                                         } else if (left is LongConstant){
1728                                                 long ll = ((LongConstant) left).Value;
1729
1730                                                 if (ll > 0)
1731                                                         left = new ULongConstant ((ulong) ll);
1732                                         } else {
1733                                                 e = ImplicitNumericConversion (ec, left, r, loc);
1734                                                 if (e != null)
1735                                                         left = e;
1736                                         }
1737                                         other = left.Type;
1738                                 }
1739
1740                                 if ((other == TypeManager.sbyte_type) ||
1741                                     (other == TypeManager.short_type) ||
1742                                     (other == TypeManager.int32_type) ||
1743                                     (other == TypeManager.int64_type))
1744                                         Error_OperatorAmbiguous (loc, oper, l, r);
1745                                 type = TypeManager.uint64_type;
1746                         } else if (l == TypeManager.int64_type || r == TypeManager.int64_type){
1747                                 //
1748                                 // If either operand is of type long, the other operand is converted
1749                                 // to type long.
1750                                 //
1751                                 if (l != TypeManager.int64_type)
1752                                         left = ConvertImplicit (ec, left, TypeManager.int64_type, loc);
1753                                 if (r != TypeManager.int64_type)
1754                                         right = ConvertImplicit (ec, right, TypeManager.int64_type, loc);
1755
1756                                 type = TypeManager.int64_type;
1757                         } else if (l == TypeManager.uint32_type || r == TypeManager.uint32_type){
1758                                 //
1759                                 // If either operand is of type uint, and the other
1760                                 // operand is of type sbyte, short or int, othe operands are
1761                                 // converted to type long.
1762                                 //
1763                                 Type other = null;
1764
1765                                 if (l == TypeManager.uint32_type){
1766                                         if (right is IntConstant){
1767                                                 IntConstant ic = (IntConstant) right;
1768                                                 int val = ic.Value;
1769
1770                                                 if (val >= 0)
1771                                                         right = new UIntConstant ((uint) val);
1772
1773                                                 type = l;
1774                                                 return true;
1775                                         }
1776                                         other = r;
1777                                 }
1778                                 else if (r == TypeManager.uint32_type){
1779                                         if (left is IntConstant){
1780                                                 IntConstant ic = (IntConstant) left;
1781                                                 int val = ic.Value;
1782
1783                                                 if (val >= 0)
1784                                                         left = new UIntConstant ((uint) val);
1785
1786                                                 type = r;
1787                                                 return true;
1788                                         }
1789
1790                                         other = l;
1791                                 }
1792
1793                                 if ((other == TypeManager.sbyte_type) ||
1794                                     (other == TypeManager.short_type) ||
1795                                     (other == TypeManager.int32_type)){
1796                                         left = ForceConversion (ec, left, TypeManager.int64_type);
1797                                         right = ForceConversion (ec, right, TypeManager.int64_type);
1798                                         type = TypeManager.int64_type;
1799                                 } else {
1800                                         //
1801                                         // if either operand is of type uint, the other
1802                                         // operand is converd to type uint
1803                                         //
1804                                         left = ForceConversion (ec, left, TypeManager.uint32_type);
1805                                         right = ForceConversion (ec, right, TypeManager.uint32_type);
1806                                         type = TypeManager.uint32_type;
1807                                 }
1808                         } else if (l == TypeManager.decimal_type || r == TypeManager.decimal_type){
1809                                 if (l != TypeManager.decimal_type)
1810                                         left = ConvertImplicit (ec, left, TypeManager.decimal_type, loc);
1811
1812                                 if (r != TypeManager.decimal_type)
1813                                         right = ConvertImplicit (ec, right, TypeManager.decimal_type, loc);
1814                                 type = TypeManager.decimal_type;
1815                         } else {
1816                                 left = ForceConversion (ec, left, TypeManager.int32_type);
1817                                 right = ForceConversion (ec, right, TypeManager.int32_type);
1818
1819                                 type = TypeManager.int32_type;
1820                         }
1821
1822                         return (left != null) && (right != null);
1823                 }
1824
1825                 static public void Error_OperatorCannotBeApplied (Location loc, string name, Type l, Type r)
1826                 {
1827                         Report.Error (19, loc,
1828                                "Operator " + name + " cannot be applied to operands of type '" +
1829                                TypeManager.MonoBASIC_Name (l) + "' and '" +
1830                                TypeManager.MonoBASIC_Name (r) + "'");
1831                 }
1832
1833                 void Error_OperatorCannotBeApplied ()
1834                 {
1835                         Error_OperatorCannotBeApplied (loc, OperName (oper), left.Type, right.Type);
1836                 }
1837
1838                 static bool is_32_or_64 (Type t)
1839                 {
1840                         return (t == TypeManager.int32_type || t == TypeManager.uint32_type ||
1841                                 t == TypeManager.int64_type || t == TypeManager.uint64_type);
1842                 }
1843
1844                 static bool is_unsigned (Type t)
1845                 {
1846                         return (t == TypeManager.uint32_type || t == TypeManager.uint64_type ||
1847                                 t == TypeManager.short_type || t == TypeManager.byte_type);
1848                 }
1849
1850                 Expression CheckShiftArguments (EmitContext ec)
1851                 {
1852                         Expression e;
1853                         Type l = left.Type;
1854                         Type r = right.Type;
1855
1856                         e = ForceConversion (ec, right, TypeManager.int32_type);
1857                         if (e == null){
1858                                 Error_OperatorCannotBeApplied ();
1859                                 return null;
1860                         }
1861                         right = e;
1862
1863                         if (((e = ConvertImplicit (ec, left, TypeManager.int32_type, loc)) != null) ||
1864                             ((e = ConvertImplicit (ec, left, TypeManager.uint32_type, loc)) != null) ||
1865                             ((e = ConvertImplicit (ec, left, TypeManager.int64_type, loc)) != null) ||
1866                             ((e = ConvertImplicit (ec, left, TypeManager.uint64_type, loc)) != null)){
1867                                 left = e;
1868                                 type = e.Type;
1869
1870                                 return this;
1871                         }
1872                         Error_OperatorCannotBeApplied ();
1873                         return null;
1874                 }
1875
1876                 Expression ResolveOperator (EmitContext ec)
1877                 {
1878                         Type l = left.Type;
1879                         Type r = right.Type;
1880
1881                         bool overload_failed = false;
1882
1883                         //
1884                         // Step 1: Perform Operator Overload location
1885                         //
1886                         Expression left_expr, right_expr;
1887
1888                         string op = oper_names [(int) oper];
1889
1890                         MethodGroupExpr union;
1891                         left_expr = MemberLookup (ec, l, op, MemberTypes.Method, AllBindingFlags, loc);
1892                         if (r != l){
1893                                 right_expr = MemberLookup (
1894                                         ec, r, op, MemberTypes.Method, AllBindingFlags, loc);
1895                                 union = Invocation.MakeUnionSet (left_expr, right_expr, loc);
1896                         } else
1897                                 union = (MethodGroupExpr) left_expr;
1898
1899                         if (union != null) {
1900                                 Arguments = new ArrayList ();
1901                                 Arguments.Add (new Argument (left, Argument.AType.Expression));
1902                                 Arguments.Add (new Argument (right, Argument.AType.Expression));
1903
1904                                 method = Invocation.OverloadResolve (ec, union, Arguments, Location.Null);
1905                                 if (method != null) {
1906                                         MethodInfo mi = (MethodInfo) method;
1907
1908                                         type = mi.ReturnType;
1909                                         return this;
1910                                 } else {
1911                                         overload_failed = true;
1912                                 }
1913                         }
1914
1915                         //
1916                         // Step 2: Default operations on CLI native types.
1917                         //
1918
1919                         //
1920                         // Step 0: String concatenation (because overloading will get this wrong)
1921                         //
1922                         if (oper == Operator.Addition){
1923                                 //
1924                                 // If any of the arguments is a string, cast to string
1925                                 //
1926
1927                                 if (l == TypeManager.string_type){
1928
1929                                         if (r == TypeManager.void_type) {
1930                                                 Error_OperatorCannotBeApplied ();
1931                                                 return null;
1932                                         }
1933
1934                                         if (r == TypeManager.string_type){
1935                                                 if (left is Constant && right is Constant){
1936                                                         StringConstant ls = (StringConstant) left;
1937                                                         StringConstant rs = (StringConstant) right;
1938
1939                                                         return new StringConstant (
1940                                                                 ls.Value + rs.Value);
1941                                                 }
1942
1943                                                 // string + string
1944                                                 method = TypeManager.string_concat_string_string;
1945                                         } else {
1946                                                 // string + object
1947                                                 method = TypeManager.string_concat_object_object;
1948                                                 right = ConvertImplicit (ec, right,
1949                                                                          TypeManager.object_type, loc);
1950                                                 if (right == null){
1951                                                         Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
1952                                                         return null;
1953                                                 }
1954                                         }
1955                                         type = TypeManager.string_type;
1956
1957                                         Arguments = new ArrayList ();
1958                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
1959                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
1960
1961                                         return this;
1962
1963                                 } else if (r == TypeManager.string_type){
1964                                         // object + string
1965
1966                                         if (l == TypeManager.void_type) {
1967                                                 Error_OperatorCannotBeApplied ();
1968                                                 return null;
1969                                         }
1970
1971                                         method = TypeManager.string_concat_object_object;
1972                                         left = ConvertImplicit (ec, left, TypeManager.object_type, loc);
1973                                         if (left == null){
1974                                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
1975                                                 return null;
1976                                         }
1977                                         Arguments = new ArrayList ();
1978                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
1979                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
1980
1981                                         type = TypeManager.string_type;
1982
1983                                         return this;
1984                                 }
1985
1986                                 //
1987                                 // Transform a + ( - b) into a - b
1988                                 //
1989                                 if (right is Unary){
1990                                         Unary right_unary = (Unary) right;
1991
1992                                         if (right_unary.Oper == Unary.Operator.UnaryNegation){
1993                                                 oper = Operator.Subtraction;
1994                                                 right = right_unary.Expr;
1995                                                 r = right.Type;
1996                                         }
1997                                 }
1998                         }
1999
2000                         if (oper == Operator.Equality || oper == Operator.Inequality){
2001                                 if (l == TypeManager.bool_type || r == TypeManager.bool_type){
2002                                         if (r != TypeManager.bool_type || l != TypeManager.bool_type){
2003                                                 Error_OperatorCannotBeApplied ();
2004                                                 return null;
2005                                         }
2006
2007                                         type = TypeManager.bool_type;
2008                                         return this;
2009                                 }
2010
2011                                 //
2012                                 // operator != (object a, object b)
2013                                 // operator == (object a, object b)
2014                                 //
2015                                 // For this to be used, both arguments have to be reference-types.
2016                                 // Read the rationale on the spec (14.9.6)
2017                                 //
2018                                 // Also, if at compile time we know that the classes do not inherit
2019                                 // one from the other, then we catch the error there.
2020                                 //
2021                                 if (!(l.IsValueType || r.IsValueType)){
2022                                         type = TypeManager.bool_type;
2023
2024                                         if (l == r)
2025                                                 return this;
2026
2027                                         if (l.IsSubclassOf (r) || r.IsSubclassOf (l))
2028                                                 return this;
2029
2030                                         //
2031                                         // Also, a standard conversion must exist from either one
2032                                         //
2033                                         if (!(StandardConversionExists (left, r) ||
2034                                               StandardConversionExists (right, l))){
2035                                                 Error_OperatorCannotBeApplied ();
2036                                                 return null;
2037                                         }
2038                                         //
2039                                         // We are going to have to convert to an object to compare
2040                                         //
2041                                         if (l != TypeManager.object_type)
2042                                                 left = new EmptyCast (left, TypeManager.object_type);
2043                                         if (r != TypeManager.object_type)
2044                                                 right = new EmptyCast (right, TypeManager.object_type);
2045
2046                                         //
2047                                         // FIXME: CSC here catches errors cs254 and cs252
2048                                         //
2049                                         return this;
2050                                 }
2051
2052                                 //
2053                                 // One of them is a valuetype, but the other one is not.
2054                                 //
2055                                 if (!l.IsValueType || !r.IsValueType) {
2056                                         Error_OperatorCannotBeApplied ();
2057                                         return null;
2058                                 }
2059                         }
2060
2061                         // Only perform numeric promotions on:
2062                         // +, -, *, /, %, &, |, ^, ==, !=, <, >, <=, >=
2063                         //
2064                         if (oper == Operator.Addition || oper == Operator.Subtraction) {
2065                                 if (l.IsSubclassOf (TypeManager.delegate_type) &&
2066                                     r.IsSubclassOf (TypeManager.delegate_type)) {
2067
2068                                         Arguments = new ArrayList ();
2069                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
2070                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
2071
2072                                         if (oper == Operator.Addition)
2073                                                 method = TypeManager.delegate_combine_delegate_delegate;
2074                                         else
2075                                                 method = TypeManager.delegate_remove_delegate_delegate;
2076
2077                                         if (l != r) {
2078                                                 Error_OperatorCannotBeApplied ();
2079                                                 return null;
2080                                         }
2081
2082                                         DelegateOperation = true;
2083                                         type = l;
2084                                         return this;
2085                                 }
2086
2087                                 //
2088                                 // Pointer arithmetic:
2089                                 //
2090                                 // T* operator + (T* x, int y);
2091                                 // T* operator + (T* x, uint y);
2092                                 // T* operator + (T* x, long y);
2093                                 // T* operator + (T* x, ulong y);
2094                                 //
2095                                 // T* operator + (int y,   T* x);
2096                                 // T* operator + (uint y,  T *x);
2097                                 // T* operator + (long y,  T *x);
2098                                 // T* operator + (ulong y, T *x);
2099                                 //
2100                                 // T* operator - (T* x, int y);
2101                                 // T* operator - (T* x, uint y);
2102                                 // T* operator - (T* x, long y);
2103                                 // T* operator - (T* x, ulong y);
2104                                 //
2105                                 // long operator - (T* x, T *y)
2106                                 //
2107                                 if (l.IsPointer){
2108                                         if (r.IsPointer && oper == Operator.Subtraction){
2109                                                 if (r == l)
2110                                                         return new PointerArithmetic (
2111                                                                 false, left, right, TypeManager.int64_type,
2112                                                                 loc);
2113                                         } else if (is_32_or_64 (r))
2114                                                 return new PointerArithmetic (
2115                                                         oper == Operator.Addition, left, right, l, loc);
2116                                 } else if (r.IsPointer && is_32_or_64 (l) && oper == Operator.Addition)
2117                                         return new PointerArithmetic (
2118                                                 true, right, left, r, loc);
2119                         }
2120
2121                         //
2122                         // Enumeration operators
2123                         //
2124                         bool lie = TypeManager.IsEnumType (l);
2125                         bool rie = TypeManager.IsEnumType (r);
2126                         if (lie || rie){
2127                                 Expression temp;
2128
2129                                 // U operator - (E e, E f)
2130                                 if (lie && rie && oper == Operator.Subtraction){
2131                                         if (l == r){
2132                                                 type = TypeManager.EnumToUnderlying (l);
2133                                                 return this;
2134                                         }
2135                                         Error_OperatorCannotBeApplied ();
2136                                         return null;
2137                                 }
2138
2139                                 //
2140                                 // operator + (E e, U x)
2141                                 // operator - (E e, U x)
2142                                 //
2143                                 if (oper == Operator.Addition || oper == Operator.Subtraction){
2144                                         Type enum_type = lie ? l : r;
2145                                         Type other_type = lie ? r : l;
2146                                         Type underlying_type = TypeManager.EnumToUnderlying (enum_type);
2147 ;
2148
2149                                         if (underlying_type != other_type){
2150                                                 Error_OperatorCannotBeApplied ();
2151                                                 return null;
2152                                         }
2153
2154                                         type = enum_type;
2155                                         return this;
2156                                 }
2157
2158                                 if (!rie){
2159                                         temp = ConvertImplicit (ec, right, l, loc);
2160                                         if (temp != null)
2161                                                 right = temp;
2162                                         else {
2163                                                 Error_OperatorCannotBeApplied ();
2164                                                 return null;
2165                                         }
2166                                 } if (!lie){
2167                                         temp = ConvertImplicit (ec, left, r, loc);
2168                                         if (temp != null){
2169                                                 left = temp;
2170                                                 l = r;
2171                                         } else {
2172                                                 Error_OperatorCannotBeApplied ();
2173                                                 return null;
2174                                         }
2175                                 }
2176
2177                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2178                                     oper == Operator.LessThanOrEqual || oper == Operator.LessThan ||
2179                                     oper == Operator.GreaterThanOrEqual || oper == Operator.GreaterThan){
2180                                         type = TypeManager.bool_type;
2181                                         return this;
2182                                 }
2183
2184                                 if (oper == Operator.BitwiseAnd ||
2185                                     oper == Operator.BitwiseOr ||
2186                                     oper == Operator.ExclusiveOr){
2187                                         type = l;
2188                                         return this;
2189                                 }
2190                                 Error_OperatorCannotBeApplied ();
2191                                 return null;
2192                         }
2193
2194                         if (oper == Operator.LeftShift || oper == Operator.RightShift)
2195                                 return CheckShiftArguments (ec);
2196
2197                         if (oper == Operator.LogicalOr || oper == Operator.LogicalAnd){
2198                                 if (l != TypeManager.bool_type || r != TypeManager.bool_type){
2199                                         Error_OperatorCannotBeApplied ();
2200                                         return null;
2201                                 }
2202
2203                                 type = TypeManager.bool_type;
2204                                 return this;
2205                         }
2206
2207                         //
2208                         // operator & (bool x, bool y)
2209                         // operator | (bool x, bool y)
2210                         // operator ^ (bool x, bool y)
2211                         //
2212                         if (l == TypeManager.bool_type && r == TypeManager.bool_type){
2213                                 if (oper == Operator.BitwiseAnd ||
2214                                     oper == Operator.BitwiseOr ||
2215                                     oper == Operator.ExclusiveOr){
2216                                         type = l;
2217                                         return this;
2218                                 }
2219                         }
2220
2221                         //
2222                         // Pointer comparison
2223                         //
2224                         if (l.IsPointer && r.IsPointer){
2225                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2226                                     oper == Operator.LessThan || oper == Operator.LessThanOrEqual ||
2227                                     oper == Operator.GreaterThan || oper == Operator.GreaterThanOrEqual){
2228                                         type = TypeManager.bool_type;
2229                                         return this;
2230                                 }
2231                         }
2232
2233                         //
2234                         // We are dealing with numbers
2235                         //
2236                         if (overload_failed){
2237                                 Error_OperatorCannotBeApplied ();
2238                                 return null;
2239                         }
2240
2241                         //
2242                         // This will leave left or right set to null if there is an error
2243                         //
2244                         DoNumericPromotions (ec, l, r);
2245                         if (left == null || right == null){
2246                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
2247                                 return null;
2248                         }
2249
2250                         //
2251                         // reload our cached types if required
2252                         //
2253                         l = left.Type;
2254                         r = right.Type;
2255
2256                         if (oper == Operator.BitwiseAnd ||
2257                             oper == Operator.BitwiseOr ||
2258                             oper == Operator.ExclusiveOr){
2259                                 if (l == r){
2260                                         if (!((l == TypeManager.int32_type) ||
2261                                               (l == TypeManager.uint32_type) ||
2262                                               (l == TypeManager.int64_type) ||
2263                                               (l == TypeManager.uint64_type)))
2264                                                 type = l;
2265                                 } else {
2266                                         Error_OperatorCannotBeApplied ();
2267                                         return null;
2268                                 }
2269                         }
2270
2271                         if (oper == Operator.Equality ||
2272                             oper == Operator.Inequality ||
2273                             oper == Operator.LessThanOrEqual ||
2274                             oper == Operator.LessThan ||
2275                             oper == Operator.GreaterThanOrEqual ||
2276                             oper == Operator.GreaterThan){
2277                                 type = TypeManager.bool_type;
2278                         }
2279
2280                         return this;
2281                 }
2282
2283                 public override Expression DoResolve (EmitContext ec)
2284                 {
2285                         left = left.Resolve (ec);
2286                         right = right.Resolve (ec);
2287
2288                         if (left == null || right == null)
2289                                 return null;
2290
2291                         if (left.Type == null)
2292                                 throw new Exception (
2293                                         "Resolve returned non null, but did not set the type! (" +
2294                                         left + ") at Line: " + loc.Row);
2295                         if (right.Type == null)
2296                                 throw new Exception (
2297                                         "Resolve returned non null, but did not set the type! (" +
2298                                         right + ") at Line: "+ loc.Row);
2299
2300                         eclass = ExprClass.Value;
2301
2302                         if (left is Constant && right is Constant){
2303                                 Expression e = ConstantFold.BinaryFold (
2304                                         ec, oper, (Constant) left, (Constant) right, loc);
2305                                 if (e != null)
2306                                         return e;
2307                         }
2308
2309                         return ResolveOperator (ec);
2310                 }
2311
2312                 /// <remarks>
2313                 ///   EmitBranchable is called from Statement.EmitBoolExpression in the
2314                 ///   context of a conditional bool expression.  This function will return
2315                 ///   false if it is was possible to use EmitBranchable, or true if it was.
2316                 ///
2317                 ///   The expression's code is generated, and we will generate a branch to 'target'
2318                 ///   if the resulting expression value is equal to isTrue
2319                 /// </remarks>
2320                 public bool EmitBranchable (EmitContext ec, Label target, bool onTrue)
2321                 {
2322                         if (method != null)
2323                                 return false;
2324
2325                         ILGenerator ig = ec.ig;
2326
2327                         //
2328                         // This is more complicated than it looks, but its just to avoid
2329                         // duplicated tests: basically, we allow ==, !=, >, <, >= and <=
2330                         // but on top of that we want for == and != to use a special path
2331                         // if we are comparing against null
2332                         //
2333                         if (oper == Operator.Equality || oper == Operator.Inequality){
2334                                 bool my_on_true = oper == Operator.Inequality ? onTrue : !onTrue;
2335
2336                                 if (left is NullLiteral){
2337                                         right.Emit (ec);
2338                                         if (my_on_true)
2339                                                 ig.Emit (OpCodes.Brtrue, target);
2340                                         else
2341                                                 ig.Emit (OpCodes.Brfalse, target);
2342                                         return true;
2343                                 } else if (right is NullLiteral){
2344                                         left.Emit (ec);
2345                                         if (my_on_true)
2346                                                 ig.Emit (OpCodes.Brtrue, target);
2347                                         else
2348                                                 ig.Emit (OpCodes.Brfalse, target);
2349                                         return true;
2350                                 }
2351                         } else if (!(oper == Operator.LessThan ||
2352                                       oper == Operator.GreaterThan ||
2353                                       oper == Operator.LessThanOrEqual ||
2354                                       oper == Operator.GreaterThanOrEqual))
2355                                 return false;
2356
2357
2358
2359                         left.Emit (ec);
2360                         right.Emit (ec);
2361
2362                         bool isUnsigned = is_unsigned (left.Type);
2363
2364                         switch (oper){
2365                         case Operator.Equality:
2366                                 if (onTrue)
2367                                         ig.Emit (OpCodes.Beq, target);
2368                                 else
2369                                         ig.Emit (OpCodes.Bne_Un, target);
2370                                 break;
2371
2372                         case Operator.Inequality:
2373                                 if (onTrue)
2374                                         ig.Emit (OpCodes.Bne_Un, target);
2375                                 else
2376                                         ig.Emit (OpCodes.Beq, target);
2377                                 break;
2378
2379                         case Operator.LessThan:
2380                                 if (onTrue)
2381                                         if (isUnsigned)
2382                                                 ig.Emit (OpCodes.Blt_Un, target);
2383                                         else
2384                                                 ig.Emit (OpCodes.Blt, target);
2385                                 else
2386                                         if (isUnsigned)
2387                                                 ig.Emit (OpCodes.Bge_Un, target);
2388                                         else
2389                                                 ig.Emit (OpCodes.Bge, target);
2390                                 break;
2391
2392                         case Operator.GreaterThan:
2393                                 if (onTrue)
2394                                         if (isUnsigned)
2395                                                 ig.Emit (OpCodes.Bgt_Un, target);
2396                                         else
2397                                                 ig.Emit (OpCodes.Bgt, target);
2398                                 else
2399                                         if (isUnsigned)
2400                                                 ig.Emit (OpCodes.Ble_Un, target);
2401                                         else
2402                                                 ig.Emit (OpCodes.Ble, target);
2403                                 break;
2404
2405                         case Operator.LessThanOrEqual:
2406                                 if (onTrue)
2407                                         if (isUnsigned)
2408                                                 ig.Emit (OpCodes.Ble_Un, target);
2409                                         else
2410                                                 ig.Emit (OpCodes.Ble, target);
2411                                 else
2412                                         if (isUnsigned)
2413                                                 ig.Emit (OpCodes.Bgt_Un, target);
2414                                         else
2415                                                 ig.Emit (OpCodes.Bgt, target);
2416                                 break;
2417
2418
2419                         case Operator.GreaterThanOrEqual:
2420                                 if (onTrue)
2421                                         if (isUnsigned)
2422                                                 ig.Emit (OpCodes.Bge_Un, target);
2423                                         else
2424                                                 ig.Emit (OpCodes.Bge, target);
2425                                 else
2426                                         if (isUnsigned)
2427                                                 ig.Emit (OpCodes.Blt_Un, target);
2428                                         else
2429                                                 ig.Emit (OpCodes.Blt, target);
2430                                 break;
2431
2432                         default:
2433                                 return false;
2434                         }
2435
2436                         return true;
2437                 }
2438
2439                 public override void Emit (EmitContext ec)
2440                 {
2441                         ILGenerator ig = ec.ig;
2442                         Type l = left.Type;
2443                         Type r = right.Type;
2444                         OpCode opcode;
2445
2446                         if (method != null) {
2447
2448                                 // Note that operators are static anyway
2449
2450                                 if (Arguments != null)
2451                                         Invocation.EmitArguments (ec, method, Arguments);
2452
2453                                 if (method is MethodInfo)
2454                                         ig.Emit (OpCodes.Call, (MethodInfo) method);
2455                                 else
2456                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
2457
2458                                 if (DelegateOperation)
2459                                         ig.Emit (OpCodes.Castclass, type);
2460
2461                                 return;
2462                         }
2463
2464                         //
2465                         // Handle short-circuit operators differently
2466                         // than the rest
2467                         //
2468                         if (oper == Operator.LogicalAnd){
2469                                 Label load_zero = ig.DefineLabel ();
2470                                 Label end = ig.DefineLabel ();
2471
2472                                 left.Emit (ec);
2473                                 ig.Emit (OpCodes.Brfalse, load_zero);
2474                                 right.Emit (ec);
2475                                 ig.Emit (OpCodes.Br, end);
2476                                 ig.MarkLabel (load_zero);
2477                                 ig.Emit (OpCodes.Ldc_I4_0);
2478                                 ig.MarkLabel (end);
2479                                 return;
2480                         } else if (oper == Operator.LogicalOr){
2481                                 Label load_one = ig.DefineLabel ();
2482                                 Label end = ig.DefineLabel ();
2483
2484                                 left.Emit (ec);
2485                                 ig.Emit (OpCodes.Brtrue, load_one);
2486                                 right.Emit (ec);
2487                                 ig.Emit (OpCodes.Br, end);
2488                                 ig.MarkLabel (load_one);
2489                                 ig.Emit (OpCodes.Ldc_I4_1);
2490                                 ig.MarkLabel (end);
2491                                 return;
2492                         }
2493
2494                         left.Emit (ec);
2495                         right.Emit (ec);
2496
2497                         switch (oper){
2498                         case Operator.Multiply:
2499                                 if (ec.CheckState){
2500                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2501                                                 opcode = OpCodes.Mul_Ovf;
2502                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2503                                                 opcode = OpCodes.Mul_Ovf_Un;
2504                                         else
2505                                                 opcode = OpCodes.Mul;
2506                                 } else
2507                                         opcode = OpCodes.Mul;
2508
2509                                 break;
2510
2511                         case Operator.Division:
2512                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2513                                         opcode = OpCodes.Div_Un;
2514                                 else
2515                                         opcode = OpCodes.Div;
2516                                 break;
2517
2518                         case Operator.Modulus:
2519                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2520                                         opcode = OpCodes.Rem_Un;
2521                                 else
2522                                         opcode = OpCodes.Rem;
2523                                 break;
2524
2525                         case Operator.Addition:
2526                                 if (ec.CheckState){
2527                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2528                                                 opcode = OpCodes.Add_Ovf;
2529                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2530                                                 opcode = OpCodes.Add_Ovf_Un;
2531                                         else
2532                                                 opcode = OpCodes.Add;
2533                                 } else
2534                                         opcode = OpCodes.Add;
2535                                 break;
2536
2537                         case Operator.Subtraction:
2538                                 if (ec.CheckState){
2539                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2540                                                 opcode = OpCodes.Sub_Ovf;
2541                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2542                                                 opcode = OpCodes.Sub_Ovf_Un;
2543                                         else
2544                                                 opcode = OpCodes.Sub;
2545                                 } else
2546                                         opcode = OpCodes.Sub;
2547                                 break;
2548
2549                         case Operator.RightShift:
2550                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2551                                         opcode = OpCodes.Shr_Un;
2552                                 else
2553                                         opcode = OpCodes.Shr;
2554                                 break;
2555
2556                         case Operator.LeftShift:
2557                                 opcode = OpCodes.Shl;
2558                                 break;
2559
2560                         case Operator.Equality:
2561                                 opcode = OpCodes.Ceq;
2562                                 break;
2563
2564                         case Operator.Inequality:
2565                                 ec.ig.Emit (OpCodes.Ceq);
2566                                 ec.ig.Emit (OpCodes.Ldc_I4_0);
2567
2568                                 opcode = OpCodes.Ceq;
2569                                 break;
2570
2571                         case Operator.LessThan:
2572                                 opcode = OpCodes.Clt;
2573                                 break;
2574
2575                         case Operator.GreaterThan:
2576                                 opcode = OpCodes.Cgt;
2577                                 break;
2578
2579                         case Operator.LessThanOrEqual:
2580                                 ec.ig.Emit (OpCodes.Cgt);
2581                                 ec.ig.Emit (OpCodes.Ldc_I4_0);
2582
2583                                 opcode = OpCodes.Ceq;
2584                                 break;
2585
2586                         case Operator.GreaterThanOrEqual:
2587                                 ec.ig.Emit (OpCodes.Clt);
2588                                 ec.ig.Emit (OpCodes.Ldc_I4_1);
2589
2590                                 opcode = OpCodes.Sub;
2591                                 break;
2592
2593                         case Operator.BitwiseOr:
2594                                 opcode = OpCodes.Or;
2595                                 break;
2596
2597                         case Operator.BitwiseAnd:
2598                                 opcode = OpCodes.And;
2599                                 break;
2600
2601                         case Operator.ExclusiveOr:
2602                                 opcode = OpCodes.Xor;
2603                                 break;
2604
2605                         default:
2606                                 throw new Exception ("This should not happen: Operator = "
2607                                                      + oper.ToString ());
2608                         }
2609
2610                         ig.Emit (opcode);
2611                 }
2612
2613                 public bool IsBuiltinOperator {
2614                         get {
2615                                 return method == null;
2616                         }
2617                 }
2618         }
2619
2620         public class PointerArithmetic : Expression {
2621                 Expression left, right;
2622                 bool is_add;
2623
2624                 //
2625                 // We assume that 'l' is always a pointer
2626                 //
2627                 public PointerArithmetic (bool is_addition, Expression l, Expression r, Type t,
2628                                           Location loc)
2629                 {
2630                         type = t;
2631                         eclass = ExprClass.Variable;
2632                         this.loc = loc;
2633                         left = l;
2634                         right = r;
2635                         is_add = is_addition;
2636                 }
2637
2638                 public override Expression DoResolve (EmitContext ec)
2639                 {
2640                         //
2641                         // We are born fully resolved
2642                         //
2643                         return this;
2644                 }
2645
2646                 public override void Emit (EmitContext ec)
2647                 {
2648                         Type op_type = left.Type;
2649                         ILGenerator ig = ec.ig;
2650                         int size = GetTypeSize (op_type.GetElementType ());
2651
2652                         if (right.Type.IsPointer){
2653                                 //
2654                                 // handle (pointer - pointer)
2655                                 //
2656                                 left.Emit (ec);
2657                                 right.Emit (ec);
2658                                 ig.Emit (OpCodes.Sub);
2659
2660                                 if (size != 1){
2661                                         if (size == 0)
2662                                                 ig.Emit (OpCodes.Sizeof, op_type);
2663                                         else
2664                                                 IntLiteral.EmitInt (ig, size);
2665                                         ig.Emit (OpCodes.Div);
2666                                 }
2667                                 ig.Emit (OpCodes.Conv_I8);
2668                         } else {
2669                                 //
2670                                 // handle + and - on (pointer op int)
2671                                 //
2672                                 left.Emit (ec);
2673                                 ig.Emit (OpCodes.Conv_I);
2674                                 right.Emit (ec);
2675                                 if (size != 1){
2676                                         if (size == 0)
2677                                                 ig.Emit (OpCodes.Sizeof, op_type);
2678                                         else
2679                                                 IntLiteral.EmitInt (ig, size);
2680                                         ig.Emit (OpCodes.Mul);
2681                                 }
2682                                 if (is_add)
2683                                         ig.Emit (OpCodes.Add);
2684                                 else
2685                                         ig.Emit (OpCodes.Sub);
2686                         }
2687                 }
2688         }
2689
2690         /// <summary>
2691         ///   Implements the ternary conditional operator (?:)
2692         /// </summary>
2693         public class Conditional : Expression {
2694                 Expression expr, trueExpr, falseExpr;
2695
2696                 public Conditional (Expression expr, Expression trueExpr, Expression falseExpr, Location l)
2697                 {
2698                         this.expr = expr;
2699                         this.trueExpr = trueExpr;
2700                         this.falseExpr = falseExpr;
2701                         this.loc = l;
2702                 }
2703
2704                 public Expression Expr {
2705                         get {
2706                                 return expr;
2707                         }
2708                 }
2709
2710                 public Expression TrueExpr {
2711                         get {
2712                                 return trueExpr;
2713                         }
2714                 }
2715
2716                 public Expression FalseExpr {
2717                         get {
2718                                 return falseExpr;
2719                         }
2720                 }
2721
2722                 public override Expression DoResolve (EmitContext ec)
2723                 {
2724                         expr = expr.Resolve (ec);
2725
2726                         if (expr == null)
2727                                 return null;
2728
2729                         if (expr.Type != TypeManager.bool_type)
2730                                 expr = Expression.ConvertImplicitRequired (
2731                                         ec, expr, TypeManager.bool_type, loc);
2732
2733                         trueExpr = trueExpr.Resolve (ec);
2734                         falseExpr = falseExpr.Resolve (ec);
2735
2736                         if (trueExpr == null || falseExpr == null)
2737                                 return null;
2738
2739                         eclass = ExprClass.Value;
2740                         if (trueExpr.Type == falseExpr.Type)
2741                                 type = trueExpr.Type;
2742                         else {
2743                                 Expression conv;
2744                                 Type true_type = trueExpr.Type;
2745                                 Type false_type = falseExpr.Type;
2746
2747                                 if (trueExpr is NullLiteral){
2748                                         type = false_type;
2749                                         return this;
2750                                 } else if (falseExpr is NullLiteral){
2751                                         type = true_type;
2752                                         return this;
2753                                 }
2754
2755                                 //
2756                                 // First, if an implicit conversion exists from trueExpr
2757                                 // to falseExpr, then the result type is of type falseExpr.Type
2758                                 //
2759                                 conv = ConvertImplicit (ec, trueExpr, false_type, loc);
2760                                 if (conv != null){
2761                                         //
2762                                         // Check if both can convert implicitl to each other's type
2763                                         //
2764                                         if (ConvertImplicit (ec, falseExpr, true_type, loc) != null){
2765                                                 Error (172,
2766                                                        "Can not compute type of conditional expression " +
2767                                                        "as '" + TypeManager.MonoBASIC_Name (trueExpr.Type) +
2768                                                        "' and '" + TypeManager.MonoBASIC_Name (falseExpr.Type) +
2769                                                        "' convert implicitly to each other");
2770                                                 return null;
2771                                         }
2772                                         type = false_type;
2773                                         trueExpr = conv;
2774                                 } else if ((conv = ConvertImplicit(ec, falseExpr, true_type,loc))!= null){
2775                                         type = true_type;
2776                                         falseExpr = conv;
2777                                 } else {
2778                                         Error (173, "The type of the conditional expression can " +
2779                                                "not be computed because there is no implicit conversion" +
2780                                                " from '" + TypeManager.MonoBASIC_Name (trueExpr.Type) + "'" +
2781                                                " and '" + TypeManager.MonoBASIC_Name (falseExpr.Type) + "'");
2782                                         return null;
2783                                 }
2784                         }
2785
2786                         if (expr is BoolConstant){
2787                                 BoolConstant bc = (BoolConstant) expr;
2788
2789                                 if (bc.Value)
2790                                         return trueExpr;
2791                                 else
2792                                         return falseExpr;
2793                         }
2794
2795                         return this;
2796                 }
2797
2798                 public override void Emit (EmitContext ec)
2799                 {
2800                         ILGenerator ig = ec.ig;
2801                         Label false_target = ig.DefineLabel ();
2802                         Label end_target = ig.DefineLabel ();
2803
2804                         Statement.EmitBoolExpression (ec, expr, false_target, false);
2805                         trueExpr.Emit (ec);
2806                         ig.Emit (OpCodes.Br, end_target);
2807                         ig.MarkLabel (false_target);
2808                         falseExpr.Emit (ec);
2809                         ig.MarkLabel (end_target);
2810                 }
2811
2812         }
2813
2814         /// <summary>
2815         ///   Local variables
2816         /// </summary>
2817         public class LocalVariableReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
2818                 public readonly string Name;
2819                 public readonly Block Block;
2820                 VariableInfo variable_info;
2821                 bool is_readonly;
2822
2823                 public LocalVariableReference (Block block, string name, Location l)
2824                 {
2825                         Block = block;
2826                         Name = name;
2827                         loc = l;
2828                         eclass = ExprClass.Variable;
2829                 }
2830
2831                 // Setting 'is_readonly' to false will allow you to create a writable
2832                 // reference to a read-only variable.  This is used by foreach and using.
2833                 public LocalVariableReference (Block block, string name, Location l,
2834                                                VariableInfo variable_info, bool is_readonly)
2835                         : this (block, name, l)
2836                 {
2837                         this.variable_info = variable_info;
2838                         this.is_readonly = is_readonly;
2839                 }
2840
2841                 public VariableInfo VariableInfo {
2842                         get {
2843                                 if (variable_info == null) {
2844                                         variable_info = Block.GetVariableInfo (Name);
2845                                         is_readonly = variable_info.ReadOnly;
2846                                 }
2847                                 return variable_info;
2848                         }
2849                 }
2850
2851                 public bool IsAssigned (EmitContext ec, Location loc)
2852                 {
2853                         return VariableInfo.IsAssigned (ec, loc);
2854                 }
2855
2856                 public bool IsFieldAssigned (EmitContext ec, string name, Location loc)
2857                 {
2858                         return VariableInfo.IsFieldAssigned (ec, name, loc);
2859                 }
2860
2861                 public void SetAssigned (EmitContext ec)
2862                 {
2863                         VariableInfo.SetAssigned (ec);
2864                 }
2865
2866                 public void SetFieldAssigned (EmitContext ec, string name)
2867                 {
2868                         VariableInfo.SetFieldAssigned (ec, name);
2869                 }
2870
2871                 public bool IsReadOnly {
2872                         get {
2873                                 if (variable_info == null) {
2874                                         variable_info = Block.GetVariableInfo (Name);
2875                                         is_readonly = variable_info.ReadOnly;
2876                                 }
2877                                 return is_readonly;
2878                         }
2879                 }
2880
2881                 public override Expression DoResolve (EmitContext ec)
2882                 {
2883                         VariableInfo vi = VariableInfo;
2884
2885                         if (Block.IsConstant (Name)) {
2886                                 Expression e = Block.GetConstantExpression (Name);
2887
2888                                 vi.Used = true;
2889                                 return e;
2890                         }
2891
2892                         if (ec.DoFlowAnalysis && !IsAssigned (ec, loc))
2893                                 return null;
2894
2895                         type = vi.VariableType;
2896                         return this;
2897                 }
2898
2899                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
2900                 {
2901                         VariableInfo vi = VariableInfo;
2902
2903                         if (ec.DoFlowAnalysis)
2904                                 ec.SetVariableAssigned (vi);
2905
2906                         Expression e = DoResolve (ec);
2907
2908                         if (e == null)
2909                                 return null;
2910
2911                         if (is_readonly){
2912                                 Error (1604, "cannot assign to '" + Name + "' because it is readonly");
2913                                 return null;
2914                         }
2915
2916                         return this;
2917                 }
2918
2919                 public override void Emit (EmitContext ec)
2920                 {
2921                         VariableInfo vi = VariableInfo;
2922                         ILGenerator ig = ec.ig;
2923
2924                         ig.Emit (OpCodes.Ldloc, vi.LocalBuilder);
2925                         vi.Used = true;
2926                 }
2927
2928                 public void EmitAssign (EmitContext ec, Expression source)
2929                 {
2930                         ILGenerator ig = ec.ig;
2931                         VariableInfo vi = VariableInfo;
2932
2933                         vi.Assigned = true;
2934
2935                         source.Emit (ec);
2936
2937                         ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
2938                 }
2939
2940                 public void AddressOf (EmitContext ec, AddressOp mode)
2941                 {
2942                         VariableInfo vi = VariableInfo;
2943
2944                         ec.ig.Emit (OpCodes.Ldloca, vi.LocalBuilder);
2945                 }
2946         }
2947
2948         /// <summary>
2949         ///   This represents a reference to a parameter in the intermediate
2950         ///   representation.
2951         /// </summary>
2952         public class ParameterReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
2953                 Parameters pars;
2954                 String name;
2955                 int idx;
2956                 public Parameter.Modifier mod;
2957                 public bool is_ref, is_out;
2958
2959                 public ParameterReference (Parameters pars, int idx, string name, Location loc)
2960                 {
2961                         this.pars = pars;
2962                         this.idx  = idx;
2963                         this.name = name;
2964                         this.loc = loc;
2965                         eclass = ExprClass.Variable;
2966                 }
2967
2968                 public bool IsAssigned (EmitContext ec, Location loc)
2969                 {
2970                         if (!is_out || !ec.DoFlowAnalysis)
2971                                 return true;
2972
2973                         if (!ec.CurrentBranching.IsParameterAssigned (idx)) {
2974                                 Report.Error (165, loc,
2975                                               "Use of unassigned local variable '" + name + "'");
2976                                 return false;
2977                         }
2978
2979                         return true;
2980                 }
2981
2982                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
2983                 {
2984                         if (!is_out || !ec.DoFlowAnalysis)
2985                                 return true;
2986
2987                         if (ec.CurrentBranching.IsParameterAssigned (idx))
2988                                 return true;
2989
2990                         if (!ec.CurrentBranching.IsParameterAssigned (idx, field_name)) {
2991                                 Report.Error (170, loc,
2992                                               "Use of possibly unassigned field '" + field_name + "'");
2993                                 return false;
2994                         }
2995
2996                         return true;
2997                 }
2998
2999                 public void SetAssigned (EmitContext ec)
3000                 {
3001                         if (is_out && ec.DoFlowAnalysis)
3002                                 ec.CurrentBranching.SetParameterAssigned (idx);
3003                 }
3004
3005                 public void SetFieldAssigned (EmitContext ec, string field_name)
3006                 {
3007                         if (is_out && ec.DoFlowAnalysis)
3008                                 ec.CurrentBranching.SetParameterAssigned (idx, field_name);
3009                 }
3010
3011                 //
3012                 // Notice that for ref/out parameters, the type exposed is not the
3013                 // same type exposed externally.
3014                 //
3015                 // for "ref int a":
3016                 //   externally we expose "int&"
3017                 //   here we expose       "int".
3018                 //
3019                 // We record this in "is_ref".  This means that the type system can treat
3020                 // the type as it is expected, but when we generate the code, we generate
3021                 // the alternate kind of code.
3022                 //
3023                 public override Expression DoResolve (EmitContext ec)
3024                 {
3025                         type = pars.GetParameterInfo (ec.DeclSpace, idx, out mod);
3026                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3027                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3028                         eclass = ExprClass.Variable;
3029
3030                         if (is_out && ec.DoFlowAnalysis && !IsAssigned (ec, loc))
3031                                 return null;
3032
3033                         return this;
3034                 }
3035
3036                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3037                 {
3038                         type = pars.GetParameterInfo (ec.DeclSpace, idx, out mod);
3039                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3040                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3041                         eclass = ExprClass.Variable;
3042
3043                         if (is_out && ec.DoFlowAnalysis)
3044                                 ec.SetParameterAssigned (idx);
3045
3046                         return this;
3047                 }
3048
3049                 static void EmitLdArg (ILGenerator ig, int x)
3050                 {
3051                         if (x <= 255){
3052                                 switch (x){
3053                                 case 0: ig.Emit (OpCodes.Ldarg_0); break;
3054                                 case 1: ig.Emit (OpCodes.Ldarg_1); break;
3055                                 case 2: ig.Emit (OpCodes.Ldarg_2); break;
3056                                 case 3: ig.Emit (OpCodes.Ldarg_3); break;
3057                                 default: ig.Emit (OpCodes.Ldarg_S, (byte) x); break;
3058                                 }
3059                         } else
3060                                 ig.Emit (OpCodes.Ldarg, x);
3061                 }
3062
3063                 //
3064                 // This method is used by parameters that are references, that are
3065                 // being passed as references:  we only want to pass the pointer (that
3066                 // is already stored in the parameter, not the address of the pointer,
3067                 // and not the value of the variable).
3068                 //
3069                 public void EmitLoad (EmitContext ec)
3070                 {
3071                         ILGenerator ig = ec.ig;
3072                         int arg_idx = idx;
3073
3074                         if (!ec.IsStatic)
3075                                 arg_idx++;
3076
3077                         EmitLdArg (ig, arg_idx);
3078                 }
3079
3080                 public override void Emit (EmitContext ec)
3081                 {
3082                         ILGenerator ig = ec.ig;
3083                         int arg_idx = idx;
3084
3085                         if (!ec.IsStatic)
3086                                 arg_idx++;
3087
3088                         EmitLdArg (ig, arg_idx);
3089
3090                         if (!is_ref)
3091                                 return;
3092
3093                         //
3094                         // If we are a reference, we loaded on the stack a pointer
3095                         // Now lets load the real value
3096                         //
3097                         LoadFromPtr (ig, type);
3098                 }
3099
3100                 public void EmitAssign (EmitContext ec, Expression source)
3101                 {
3102                         ILGenerator ig = ec.ig;
3103                         int arg_idx = idx;
3104
3105                         if (!ec.IsStatic)
3106                                 arg_idx++;
3107
3108                         if (is_ref)
3109                                 EmitLdArg (ig, arg_idx);
3110
3111                         source.Emit (ec);
3112
3113                         if (is_ref)
3114                                 StoreFromPtr (ig, type);
3115                         else {
3116                                 if (arg_idx <= 255)
3117                                         ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
3118                                 else
3119                                         ig.Emit (OpCodes.Starg, arg_idx);
3120                         }
3121                 }
3122
3123                 public void AddressOf (EmitContext ec, AddressOp mode)
3124                 {
3125                         int arg_idx = idx;
3126
3127                         if (!ec.IsStatic)
3128                                 arg_idx++;
3129
3130                         if (is_ref){
3131                                 if (arg_idx <= 255)
3132                                         ec.ig.Emit (OpCodes.Ldarg_S, (byte) arg_idx);
3133                                 else
3134                                         ec.ig.Emit (OpCodes.Ldarg, arg_idx);
3135                         } else {
3136                                 if (arg_idx <= 255)
3137                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
3138                                 else
3139                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
3140                         }
3141                 }
3142         }
3143
3144
3145         /// <summary>
3146         ///   Invocation of methods or delegates.
3147         /// </summary>
3148         public class Invocation : ExpressionStatement {
3149                 public ArrayList Arguments;
3150
3151                 public Expression expr;
3152                 MethodBase method = null;
3153                 bool is_base;
3154                 bool is_left_hand; // Needed for late bound calls
3155                 static Hashtable method_parameter_cache;
3156                 static MemberFilter CompareName;
3157
3158                 static Invocation ()
3159                 {
3160                         method_parameter_cache = new PtrHashtable ();
3161                 }
3162
3163                 //
3164                 // arguments is an ArrayList, but we do not want to typecast,
3165                 // as it might be null.
3166                 //
3167                 // FIXME: only allow expr to be a method invocation or a
3168                 // delegate invocation (7.5.5)
3169                 //
3170                 public Invocation (Expression expr, ArrayList arguments, Location l)
3171                 {
3172                         this.expr = expr;
3173                         Arguments = arguments;
3174                         loc = l;
3175                         CompareName = new MemberFilter (compare_name_filter);
3176                 }
3177
3178                 public Expression Expr {
3179                         get {
3180                                 return expr;
3181                         }
3182                 }
3183
3184                 /// <summary>
3185                 ///   Returns the Parameters (a ParameterData interface) for the
3186                 ///   Method 'mb'
3187                 /// </summary>
3188                 public static ParameterData GetParameterData (MethodBase mb)
3189                 {
3190                         object pd = method_parameter_cache [mb];
3191                         object ip;
3192
3193                         if (pd != null)
3194                                 return (ParameterData) pd;
3195
3196
3197                         ip = TypeManager.LookupParametersByBuilder (mb);
3198                         if (ip != null){
3199                                 method_parameter_cache [mb] = ip;
3200
3201                                 return (ParameterData) ip;
3202                         } else {
3203                                 ParameterInfo [] pi = mb.GetParameters ();
3204                                 ReflectionParameters rp = new ReflectionParameters (pi);
3205                                 method_parameter_cache [mb] = rp;
3206
3207                                 return (ParameterData) rp;
3208                         }
3209                 }
3210
3211                 enum Applicability { Same, Better, Worse };
3212
3213                 /// <summary>
3214                 ///  Determines "Better function"
3215                 /// </summary>
3216                 /// <remarks>
3217                 ///    and returns an integer indicating :
3218                 ///    0 if candidate ain't better
3219                 ///    1 if candidate is better than the current best match
3220                 /// </remarks>
3221                 static Applicability BetterFunction (EmitContext ec, ArrayList args,
3222                                             MethodBase candidate, MethodBase best,
3223                                             bool expanded_form, Location loc)
3224                 {
3225                         ParameterData candidate_pd = GetParameterData (candidate);
3226                         ParameterData best_pd;
3227                         int argument_count;
3228
3229                         if (args == null)
3230                                 argument_count = 0;
3231                         else
3232                                 argument_count = args.Count;
3233
3234                         int cand_count = candidate_pd.Count;
3235
3236                         if (cand_count == 0 && argument_count == 0)
3237                                 return Applicability.Same;
3238
3239                         if (candidate_pd.ParameterModifier (cand_count - 1) != Parameter.Modifier.PARAMS)
3240                                 if (cand_count != argument_count)
3241                                         return Applicability.Worse;
3242
3243                         best_pd = GetParameterData (best);
3244
3245                         Applicability res = Applicability.Same;
3246
3247                         for (int j = 0; j < argument_count; ++j) {
3248                                 int x, y;
3249
3250                                 Argument a = (Argument) args [j];
3251
3252                                 Type ct = candidate_pd.ParameterType (j);
3253                                 Type bt = best_pd.ParameterType (j);
3254
3255                                 if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3256                                         if (expanded_form)
3257                                                 ct = ct.GetElementType ();
3258
3259                                 if (best_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3260                                         if (expanded_form)
3261                                                 bt = bt.GetElementType ();
3262
3263                                 if (ct != bt) {
3264                                         if (!WideningConversionExists (ct, bt))
3265                                                 return Applicability.Worse;
3266                                         res = Applicability.Better;
3267                                 }
3268                         }
3269
3270                         if (res == Applicability.Same)
3271                                 if (candidate_pd.Count < best_pd.Count)
3272                                         res = Applicability.Better;
3273                                 else if (candidate_pd.Count > best_pd.Count)
3274                                         res = Applicability.Worse;
3275
3276                         return res;
3277                 }
3278
3279                 public static string FullMethodDesc (MethodBase mb)
3280                 {
3281                         string ret_type = "";
3282
3283                         if (mb is MethodInfo)
3284                                 ret_type = TypeManager.MonoBASIC_Name (((MethodInfo) mb).ReturnType) + " ";
3285
3286                         StringBuilder sb = new StringBuilder (ret_type + mb.Name);
3287                         ParameterData pd = GetParameterData (mb);
3288
3289                         int count = pd.Count;
3290                         sb.Append (" (");
3291
3292                         for (int i = count; i > 0; ) {
3293                                 i--;
3294
3295                                 sb.Append (pd.ParameterDesc (count - i - 1));
3296                                 if (i != 0)
3297                                         sb.Append (", ");
3298                         }
3299
3300                         sb.Append (")");
3301                         return sb.ToString ();
3302                 }
3303
3304                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3305                 {
3306                         MemberInfo [] miset;
3307                         MethodGroupExpr union;
3308
3309                         if (mg1 == null){
3310                                 if (mg2 == null)
3311                                         return null;
3312                                 return (MethodGroupExpr) mg2;
3313                         } else {
3314                                 if (mg2 == null)
3315                                         return (MethodGroupExpr) mg1;
3316                         }
3317
3318                         MethodGroupExpr left_set = null, right_set = null;
3319                         int length1 = 0, length2 = 0;
3320
3321                         left_set = (MethodGroupExpr) mg1;
3322                         length1 = left_set.Methods.Length;
3323
3324                         right_set = (MethodGroupExpr) mg2;
3325                         length2 = right_set.Methods.Length;
3326
3327                         ArrayList common = new ArrayList ();
3328
3329                         foreach (MethodBase l in left_set.Methods){
3330                                 foreach (MethodBase r in right_set.Methods){
3331                                         if (l != r)
3332                                                 continue;
3333                                         common.Add (r);
3334                                         break;
3335                                 }
3336                         }
3337
3338                         miset = new MemberInfo [length1 + length2 - common.Count];
3339                         left_set.Methods.CopyTo (miset, 0);
3340
3341                         int k = length1;
3342
3343                         foreach (MemberInfo mi in right_set.Methods){
3344                                 if (!common.Contains (mi))
3345                                         miset [k++] = mi;
3346                         }
3347
3348                         union = new MethodGroupExpr (miset, loc);
3349
3350                         return union;
3351                 }
3352
3353                 /// <summary>
3354                 ///  Determines is the candidate method, if a params method, is applicable
3355                 ///  in its expanded form to the given set of arguments
3356                 /// </summary>
3357                 static bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments, MethodBase candidate)
3358                 {
3359                         int arg_count;
3360
3361                         if (arguments == null)
3362                                 arg_count = 0;
3363                         else
3364                                 arg_count = arguments.Count;
3365
3366                         ParameterData pd = GetParameterData (candidate);
3367
3368                         int pd_count = pd.Count;
3369
3370                         if (pd_count == 0)
3371                                 return false;
3372
3373                         if (pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS)
3374                                 return false;
3375
3376                         if (pd_count - 1 > arg_count)
3377                                 return false;
3378
3379                         if (pd_count == 1 && arg_count == 0)
3380                                 return true;
3381
3382                         //
3383                         // If we have come this far, the case which remains is when the number of parameters
3384                         // is less than or equal to the argument count.
3385                         //
3386                         for (int i = 0; i < pd_count - 1; ++i) {
3387
3388                                 Argument a = (Argument) arguments [i];
3389
3390                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3391                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3392                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3393                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3394
3395                                 if (a_mod == p_mod) {
3396
3397                                         if (a_mod == Parameter.Modifier.NONE)
3398                                                 if (!ImplicitConversionExists (ec, a.Expr, pd.ParameterType (i)))
3399                                                         return false;
3400
3401                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3402                                                 Type pt = pd.ParameterType (i);
3403
3404                                                 if (!pt.IsByRef)
3405                                                         pt = TypeManager.LookupType (pt.FullName + "&");
3406
3407                                                 if (pt != a.Type)
3408                                                         return false;
3409                                         }
3410                                 } else
3411                                         return false;
3412
3413                         }
3414
3415                         Type element_type = pd.ParameterType (pd_count - 1).GetElementType ();
3416
3417                         for (int i = pd_count - 1; i < arg_count; i++) {
3418                                 Argument a = (Argument) arguments [i];
3419
3420                                 if (!StandardConversionExists (a.Expr, element_type))
3421                                         return false;
3422                         }
3423
3424                         return true;
3425                 }
3426
3427
3428                 protected enum ConversionType { None, Widening, Narrowing };
3429
3430                 static ConversionType CheckParameterAgainstArgument (EmitContext ec, ParameterData pd, int i, Argument a, Type ptype)
3431                 {
3432                         Parameter.Modifier a_mod = a.GetParameterModifier () &
3433                                 ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3434                         Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3435                                 ~(Parameter.Modifier.OUT | Parameter.Modifier.REF | Parameter.Modifier.OPTIONAL);
3436
3437                         if (a_mod == p_mod ||
3438                                 (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
3439                                 if (a_mod == Parameter.Modifier.NONE) {
3440                                         if (! WideningConversionExists (a.Expr, ptype) ) {
3441                                                 if (! NarrowingConversionExists (ec, a.Expr, ptype) )
3442                                                         return ConversionType.None;
3443                                                 else
3444                                                         return ConversionType.Narrowing;
3445                                         } else
3446                                                         return ConversionType.Widening;
3447                                 }
3448
3449                                 if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3450                                         Type pt = pd.ParameterType (i);
3451
3452                                         if (!pt.IsByRef)
3453                                                 pt = TypeManager.LookupType (pt.FullName + "&");
3454
3455                                         if (pt != a.Type)
3456                                                 return ConversionType.None;
3457                                 }
3458                                 return ConversionType.Widening;
3459                         } else
3460                                 return ConversionType.None;
3461                 }
3462
3463                 static bool HasArrayParameter (ParameterData pd)
3464                 {
3465                         int c = pd.Count;
3466                         return c > 0 && (pd.ParameterModifier (c - 1) & Parameter.Modifier.PARAMS) != 0;
3467                 }
3468
3469                 static int CountStandardParams (ParameterData pd)
3470                 {
3471                         int count = pd.Count;
3472                         for (int i = 0; i < count; i++) {
3473                                 Parameter.Modifier pm = pd.ParameterModifier (i);
3474                                 if ((pm & (Parameter.Modifier.OPTIONAL | Parameter.Modifier.PARAMS)) != 0)
3475                                         return i;
3476                         }
3477                         return count;
3478                 }
3479
3480                 /// <summary>
3481                 ///  Determines if the candidate method is applicable (section 14.4.2.1)
3482                 ///  to the given set of arguments
3483                 /// </summary>
3484                 static ConversionType IsApplicable (EmitContext ec, ArrayList arguments, MethodBase candidate, out bool expanded)
3485                 {
3486                         int arg_count, po_count;
3487                         Type param_type;
3488
3489                         expanded = false;
3490
3491                         if (arguments == null)
3492                                 arg_count = 0;
3493                         else
3494                                 arg_count = arguments.Count;
3495
3496                         ParameterData pd = GetParameterData (candidate);
3497                         int ps_count = CountStandardParams (pd);
3498                         int pd_count = pd.Count;
3499
3500                         // Validate argument count
3501                         if (ps_count == pd_count) {
3502                                 if (arg_count != pd_count)
3503                                         return ConversionType.None;
3504                         }
3505                         else {
3506                                 if (arg_count < ps_count)
3507                                         return ConversionType.None;
3508                                 if (!HasArrayParameter (pd) && arg_count > pd_count)
3509                                         return ConversionType.None;
3510                         }
3511                         ConversionType result = ConversionType.Widening;
3512                         ArrayList newarglist = new ArrayList();
3513                         if (arg_count > 0) {
3514                                 result = ConversionType.None;
3515                                 int array_param_index = -1;
3516                                 for (int i = 0; i < arg_count; ++i) {
3517                                         Argument a = (Argument) arguments [i];
3518                                         param_type = pd.ParameterType (i);
3519                                         Parameter.Modifier mod = pd.ParameterModifier (i);
3520                                         if (array_param_index < 0 && (mod & Parameter.Modifier.PARAMS) != 0)
3521                                                 array_param_index = i;
3522
3523                                         bool IsDelegate = TypeManager.IsDelegateType (param_type);
3524
3525                                         if (IsDelegate) {
3526                                                 if (a.ArgType == Argument.AType.AddressOf) {
3527                                                         a = new Argument ((Expression) a.Expr, Argument.AType.Expression);
3528                                                         ArrayList args = new ArrayList();
3529                                                         args.Add (a);
3530                                                         string param_name = pd.ParameterDesc(i).Replace('+', '.');
3531                                                         Expression pname = MonoBASIC.Parser.DecomposeQI (param_name, Location.Null);
3532
3533                                                         New temp_new = new New ((Expression)pname, args, Location.Null);
3534                                                         Expression del_temp = temp_new.DoResolve(ec);
3535
3536                                                         if (del_temp == null)
3537                                                                 return ConversionType.None;
3538
3539                                                         a = new Argument (del_temp, Argument.AType.Expression);
3540                                                         if (!a.Resolve(ec, Location.Null))
3541                                                                 return ConversionType.None;
3542                                                 }
3543                                         }
3544                                         else {
3545                                                 if (a.ArgType == Argument.AType.AddressOf)
3546                                                         return ConversionType.None;
3547                                         }
3548
3549                                         if ((mod & Parameter.Modifier.REF) != 0) {
3550                                                 a = new Argument (a.Expr, Argument.AType.Ref);
3551                                                 if (!a.Resolve(ec,Location.Null))
3552                                                         return ConversionType.None;
3553                                         }
3554
3555                                         ConversionType match = ConversionType.None;
3556                                         if (i == array_param_index)
3557                                                 match = CheckParameterAgainstArgument (ec, pd, i, a, param_type);
3558                                         if (match == ConversionType.None && array_param_index >= 0 && i >= array_param_index) {
3559                                                 expanded = true;
3560                                                 param_type = param_type.GetElementType ();
3561                                         }
3562                                         if (match == ConversionType.None)
3563                                                 match = CheckParameterAgainstArgument (ec, pd, i, a, param_type);
3564                                         newarglist.Add (a);
3565                                         if (match == ConversionType.None)
3566                                                 return ConversionType.None;
3567                                         if (result == ConversionType.None)
3568                                                 result = match;
3569                                         else if (match == ConversionType.Narrowing)
3570                                                 result = ConversionType.Narrowing;
3571                                 }
3572                         }
3573
3574 #if false
3575                         // We've found a candidate, so we exchange the dummy NoArg arguments
3576                         // with new arguments containing the default value for that parameter
3577
3578                         ArrayList newarglist = new ArrayList();
3579                         for (int i = 0; i < arg_count; i++) {
3580                                 Argument a = (Argument) arguments [i];
3581                                 Parameter p = null;
3582
3583                                 if (ps != null)
3584                                         p = (Parameter) ps.FixedParameters[i];
3585
3586                                 if (a.ArgType == Argument.AType.NoArg){
3587                                         a = new Argument (p.ParameterInitializer, Argument.AType.Expression);
3588                                         a.Resolve(ec, Location.Null);
3589                                 }
3590
3591                                 // ToDo - This part is getting resolved second time within this function
3592                                 // This is a costly operation
3593                                 // The earlier resoved result should be used here.
3594                                 // Has to be done during compiler optimization.
3595                                 if (a.ArgType == Argument.AType.AddressOf) {
3596                                         param_type = pd.ParameterType (i);
3597                                         bool IsDelegate = TypeManager.IsDelegateType (param_type);
3598
3599                                         a = new Argument ((Expression) a.Expr, Argument.AType.Expression);
3600                                         ArrayList args = new ArrayList();
3601                                         args.Add (a);
3602                                         string param_name = pd.ParameterDesc(i).Replace('+', '.');
3603                                         Expression pname = MonoBASIC.Parser.DecomposeQI (param_name, Location.Null);
3604
3605                                         New temp_new = new New ((Expression)pname, args, Location.Null);
3606                                         Expression del_temp = temp_new.DoResolve(ec);
3607
3608                                         if (del_temp == null)
3609                                                 return ConversionType.None;
3610
3611                                         a = new Argument (del_temp, Argument.AType.Expression);
3612                                         if (!a.Resolve(ec, Location.Null))
3613                                                 return ConversionType.None;
3614                                 }
3615
3616                                 if ((p != null) && ((p.ModFlags & Parameter.Modifier.REF) != 0)) {
3617                                         a.ArgType = Argument.AType.Ref;
3618                                         a.Resolve(ec, Location.Null);
3619                                 } else if ((pd.ParameterModifier (i) & Parameter.Modifier.REF) != 0) {
3620                                         a.ArgType = Argument.AType.Ref;
3621                                         a.Resolve(ec, Location.Null);
3622                                 }
3623                                 newarglist.Add(a);
3624                                 int n = pd_count - arg_count;
3625                                 if (n > 0) {
3626                                         for (int x = 0; x < n; x++) {
3627                                                 Parameter op = (Parameter) ps.FixedParameters[x + arg_count];
3628                                                 Argument b = new Argument (op.ParameterInitializer, Argument.AType.Expression);
3629                                                 b.Resolve(ec, Location.Null);
3630                                                 newarglist.Add (b);
3631                                         }
3632                                 }
3633                         }
3634 #endif
3635                         return result;
3636                 }
3637
3638                 static bool compare_name_filter (MemberInfo m, object filterCriteria)
3639                 {
3640                         return (m.Name == ((string) filterCriteria));
3641                 }
3642
3643                 // We need an overload for OverloadResolve because Invocation.DoResolve
3644                 // must pass Arguments by reference, since a later call to IsApplicable
3645                 // can change the argument list if optional parameters are defined
3646                 // in the method declaration
3647                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
3648                                                           ArrayList Arguments, Location loc)
3649                 {
3650                         ArrayList a = Arguments;
3651                         return OverloadResolve (ec, me, ref a, loc);
3652                 }
3653
3654                 static string ToString(MethodBase mbase)
3655                 {
3656                         if (mbase == null)
3657                                 return "NULL";
3658
3659                         if (mbase is MethodBuilder)
3660                         {
3661                                 MethodBuilder mb = (MethodBuilder) mbase;
3662                                 String res = mb.ReturnType + " (";
3663                                 ParameterInfo [] parms = mb.GetParameters();
3664                                 for (int i = 0; i < parms.Length; i++) {
3665                                         if (i != 0)
3666                                                 res += " ";
3667                                         res += parms[i].ParameterType;
3668                                 }
3669                                 res += ")";
3670                                 return res;
3671                         }
3672
3673                         return mbase.ToString();
3674                 }
3675
3676                 /// <summary>
3677                 ///   Find the Applicable Function Members (7.4.2.1)
3678                 ///
3679                 ///   me: Method Group expression with the members to select.
3680                 ///       it might contain constructors or methods (or anything
3681                 ///       that maps to a method).
3682                 ///
3683                 ///   Arguments: ArrayList containing resolved Argument objects.
3684                 ///
3685                 ///   loc: The location if we want an error to be reported, or a Null
3686                 ///        location for "probing" purposes.
3687                 ///
3688                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3689                 ///            that is the best match of me on Arguments.
3690                 ///
3691                 /// </summary>
3692                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
3693                                                           ref ArrayList Arguments, Location loc)
3694                 {
3695                         ArrayList afm = new ArrayList ();
3696                         MethodBase method = null;
3697                         Type current_type = null;
3698                         int argument_count;
3699                         ArrayList candidates = new ArrayList ();
3700                         Hashtable expanded_candidates = new Hashtable();
3701                         int narrow_count = 0;
3702                         bool narrowing_candidate = false;
3703
3704                         foreach (MethodBase candidate in me.Methods){
3705                                 bool candidate_expanded;
3706                                 ConversionType m = IsApplicable (ec, Arguments, candidate, out candidate_expanded);
3707                                 if (candidate_expanded)
3708                                         expanded_candidates [candidate] = candidate;
3709                                 if (m == ConversionType.None)
3710                                         continue;
3711                                 else if (m == ConversionType.Narrowing) {
3712                                         if (method == null) {
3713                                                 method = candidate;
3714                                                 narrowing_candidate = true;
3715                                         }
3716                                         narrow_count++;
3717                                 } else if (m == ConversionType.Widening) {
3718                                         if (method == null || narrowing_candidate) {
3719                                                 method = candidate;
3720                                                 narrowing_candidate = false;
3721                                         } else {
3722                                                 Applicability res = BetterFunction (ec, Arguments, candidate, method, true, loc);
3723                                                 if (res == Applicability.Same)
3724                                                         continue; // should check it overrides?
3725                                                 if (res == Applicability.Better)
3726                                                         method = candidate;
3727                                         }
3728                                         candidates.Add (candidate);
3729                                 }
3730                         }
3731
3732                         if (candidates.Count == 0) {
3733                                 if (narrow_count > 1)
3734                                         method = null;
3735                                 else if (narrow_count == 1)
3736                                         candidates = null;
3737                         } else if (candidates.Count == 1) {
3738                                 method = (MethodBase)candidates [0];
3739                                 candidates = null;
3740                         } else
3741                                 narrow_count = 0;
3742
3743                         if (Arguments == null)
3744                                 argument_count = 0;
3745                         else
3746                                 argument_count = Arguments.Count;
3747
3748
3749                         if (method == null) {
3750                                 //
3751                                 // Okay so we have failed to find anything so we
3752                                 // return by providing info about the closest match
3753                                 //
3754                                 for (int i = 0; i < me.Methods.Length; ++i) {
3755
3756                                         MethodBase c = (MethodBase) me.Methods [i];
3757                                         ParameterData pd = GetParameterData (c);
3758
3759                                         if (pd.Count != argument_count)
3760                                                 continue;
3761
3762                                         bool dummy;
3763                                         if (narrow_count != 0) {
3764                                                 if (IsApplicable (ec, Arguments, c, out dummy) == ConversionType.None)
3765                                                         continue;
3766                                                 Report.Error (1502, loc,
3767                                                         "Overloaded match for method '" +
3768                                                         FullMethodDesc (c) +
3769                                                         "' requires narrowing conversionss");
3770                                         }
3771
3772                                         VerifyArgumentsCompat (ec, Arguments, argument_count, c, false,
3773                                                                null, loc);
3774                                 }
3775
3776                                 return null;
3777                         }
3778
3779                         //
3780                         // Now check that there are no ambiguities i.e the selected method
3781                         // should be better than all the others
3782                         //
3783
3784                         if (candidates != null) {
3785                                 foreach (MethodBase candidate in candidates){
3786                                         if (candidate == method)
3787                                                 continue;
3788
3789                                         if (BetterFunction (ec, Arguments, candidate, method,
3790                                                                 false, loc) == Applicability.Better) {
3791                                                 Report.Error (
3792                                                         121, loc,
3793                                                         "Ambiguous call of '" + me.Name + "' when selecting function due to implicit casts");
3794                                                 return null;
3795                                         }
3796                                 }
3797                         }
3798
3799                         //
3800                         // And now check if the arguments are all compatible, perform conversions
3801                         // if necessary etc. and return if everything is all right
3802                         //
3803                         if (method == null)
3804                                 return null;
3805
3806                         bool chose_params_expanded = expanded_candidates.Contains (method);
3807
3808                         Arguments = ConstructArgumentList(ec, Arguments, method);
3809                         if (VerifyArgumentsCompat (ec, Arguments, argument_count, method,
3810                                                    chose_params_expanded, null, loc))
3811                         {
3812                                 return method;
3813                         }
3814                         else
3815                                 return null;
3816                 }
3817
3818                 public static ArrayList ConstructArgumentList (EmitContext ec, ArrayList Arguments,     MethodBase method)
3819                 {
3820                         ArrayList newarglist = new ArrayList();
3821                         int arg_count = Arguments == null ? 0 : Arguments.Count;
3822
3823                         ParameterData pd = GetParameterData (method);
3824
3825                         for (int i = 0; i < arg_count; i++) {
3826                                 Argument a = (Argument) Arguments [i];
3827                                 Type param_type = pd.ParameterType (i);
3828
3829                                 bool IsDelegate = TypeManager.IsDelegateType (param_type);
3830                                 if (IsDelegate) {
3831                                         if (a.ArgType == Argument.AType.AddressOf) {
3832                                                 a = new Argument ((Expression) a.Expr, Argument.AType.Expression);
3833                                                 ArrayList args = new ArrayList();
3834                                                 args.Add (a);
3835                                                 string param_name = pd.ParameterDesc(i).Replace('+', '.');
3836                                                 Expression pname = MonoBASIC.Parser.DecomposeQI (param_name, Location.Null);
3837
3838                                                 New temp_new = new New ((Expression)pname, args, Location.Null);
3839                                                 Expression del_temp = temp_new.DoResolve(ec);
3840                                                 a = new Argument (del_temp, Argument.AType.Expression);
3841                                                 a.Resolve(ec, Location.Null);
3842                                         }
3843                                 }
3844                                 if ((pd.ParameterModifier (i) & Parameter.Modifier.REF) != 0) {
3845                                         a.ArgType = Argument.AType.Ref;
3846                                         a.Resolve(ec, Location.Null);
3847                                 }
3848
3849                                 newarglist.Add (a);
3850                         }
3851
3852                         if (HasArrayParameter (pd) && arg_count == pd.Count - 1)
3853                                 return newarglist;
3854
3855                         for (int i = arg_count; i < pd.Count; i++) {
3856                                 Expression e = pd.DefaultValue (i);
3857                                 Argument a = new Argument (e, Argument.AType.Expression);
3858                                 if ((pd.ParameterModifier (i) & Parameter.Modifier.REF) != 0)
3859                                         a.ArgType = Argument.AType.Ref;
3860                                 e.Resolve (ec);
3861                                 a.Resolve (ec, Location.Null);
3862                                 newarglist.Add (a);
3863                         }
3864
3865                         return newarglist;
3866                 }
3867
3868                 public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
3869                         int argument_count,
3870                         MethodBase method,
3871                         bool chose_params_expanded,
3872                         Type delegate_type,
3873                         Location loc)
3874                 {
3875                         return (VerifyArgumentsCompat (ec, Arguments, argument_count,
3876                                 method, chose_params_expanded, delegate_type, loc, null));
3877                 }
3878
3879                 public static bool VerifyArgumentsCompat (EmitContext ec,
3880                                                           ArrayList Arguments,
3881                                                           int argument_count,
3882                                                           MethodBase method,
3883                                                           bool chose_params_expanded,
3884                                                           Type delegate_type,
3885                                                           Location loc,
3886                                                           string InvokingProperty)
3887                 {
3888                         ParameterData pd = GetParameterData (method);
3889                         int pd_count = pd.Count;
3890
3891                         for (int j = 0; j < argument_count; j++) {
3892                                 Argument a = (Argument) Arguments [j];
3893                                 Expression a_expr = a.Expr;
3894                                 Type parameter_type = pd.ParameterType(j);
3895
3896                                 if (parameter_type == null)
3897                                 {
3898                                         Error_WrongNumArguments(loc, (InvokingProperty == null)?((delegate_type == null)?FullMethodDesc (method):delegate_type.ToString ()):InvokingProperty, argument_count);
3899                                         return false;
3900                                 }
3901                                 if (pd.ParameterModifier (j) == Parameter.Modifier.PARAMS &&
3902                                 chose_params_expanded)
3903                                         parameter_type = TypeManager.TypeToCoreType (parameter_type.GetElementType ());
3904                                 if (a.Type != parameter_type){
3905                                         Expression conv;
3906
3907                                         conv = ConvertImplicit (ec, a_expr, parameter_type, loc);
3908
3909                                         if (conv == null) {
3910                                                 if (!Location.IsNull (loc)) {
3911                                                         if (delegate_type == null)
3912                                                                 if (InvokingProperty == null)
3913                                                                         Report.Error (1502, loc,
3914                                                                                 "The best overloaded match for method '" +
3915                                                                                 FullMethodDesc (method) +
3916                                                                                 "' has some invalid arguments");
3917                                                                 else
3918                                                                         Report.Error (1502, loc,
3919                                                                                 "Property '" +
3920                                                                                 InvokingProperty +
3921                                                                                 "' has some invalid arguments");
3922                                                         else
3923                                                                 Report.Error (1594, loc,
3924                                                                               "Delegate '" + delegate_type.ToString () +
3925                                                                               "' has some invalid arguments.");
3926                                                         Report.Error (1503, loc,
3927                                                          "Argument " + (j+1) +
3928                                                          ": Cannot convert from '" + Argument.FullDesc (a)
3929                                                          + "' to '" + pd.ParameterDesc (j) + "'");
3930                                                 }
3931
3932                                                 return false;
3933                                         }
3934
3935                                         //
3936                                         // Update the argument with the implicit conversion
3937                                         //
3938                                         if (a_expr != conv)
3939                                                 a.Expr = conv;
3940                                 }
3941
3942                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3943                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3944                                 Parameter.Modifier p_mod = pd.ParameterModifier (j) &
3945                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF | Parameter.Modifier.OPTIONAL);
3946
3947                                 if (a_mod != p_mod &&
3948                                     pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
3949                                         if (!Location.IsNull (loc)) {
3950                                                 Report.Error (1502, loc,
3951                                                        "The best overloaded match for method '" + FullMethodDesc (method)+
3952                                                        "' has some invalid arguments");
3953                                                 Report.Error (1503, loc,
3954                                                        "Argument " + (j+1) +
3955                                                        ": Cannot convert from '" + Argument.FullDesc (a)
3956                                                        + "' to '" + pd.ParameterDesc (j) + "'");
3957                                         }
3958
3959                                         return false;
3960                                 }
3961                         }
3962
3963                         return true;
3964                 }
3965
3966                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
3967                 {
3968                         this.is_left_hand = true;
3969                         return DoResolve (ec);
3970                 }
3971
3972                 public override Expression DoResolve (EmitContext ec)
3973                 {
3974                         //
3975                         // First, resolve the expression that is used to
3976                         // trigger the invocation
3977                         //
3978                         Expression expr_to_return = null;
3979
3980                         if (expr is BaseAccess)
3981                                 is_base = true;
3982
3983                         if ((ec.ReturnType != null) && (expr.ToString() == ec.BlockName)) {
3984                                 ec.InvokingOwnOverload = true;
3985                                 expr = expr.Resolve (ec, ResolveFlags.MethodGroup);
3986                                 ec.InvokingOwnOverload = false;
3987                         }
3988                         else
3989                         {
3990                                 ec.InvokingOwnOverload = false;
3991                                 expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
3992                         }
3993                         if (expr == null)
3994                                 return null;
3995
3996                         if (expr is Invocation) {
3997                                 // FIXME Calls which return an Array are not resolved (here or in the grammar)
3998                                 expr = expr.Resolve(ec);
3999                         }
4000
4001                         if (!(expr is MethodGroupExpr))
4002                         {
4003                                 Type expr_type = expr.Type;
4004
4005                                 if (expr_type != null)
4006                                 {
4007                                         bool IsDelegate = TypeManager.IsDelegateType (expr_type);
4008                                         if (IsDelegate)
4009                                                 return (new DelegateInvocation (
4010                                                         this.expr, Arguments, loc)).Resolve (ec);
4011                                 }
4012                         }
4013
4014                         //
4015                         // Next, evaluate all the expressions in the argument list
4016                         //
4017                         if (Arguments != null)
4018                         {
4019                                 foreach (Argument a in Arguments)
4020                                 {
4021                                         if ((a.ArgType == Argument.AType.NoArg) && (!(expr is MethodGroupExpr)))
4022                                                 Report.Error (999, "This item cannot have empty arguments");
4023
4024                                         if (!a.Resolve (ec, loc))
4025                                                 return null;
4026                                 }
4027                         }
4028
4029                         if (expr is MethodGroupExpr)
4030                         {
4031                                 MethodGroupExpr mg = (MethodGroupExpr) expr;
4032                                 method = OverloadResolve (ec, mg, ref Arguments, loc);
4033
4034                                 if (method == null)
4035                                 {
4036                                         Error (30455,
4037                                                 "Could not find any applicable function to invoke for this argument list");
4038                                         return null;
4039                                 }
4040
4041                                 if ((method as MethodInfo) != null)
4042                                 {
4043                                         MethodInfo mi = method as MethodInfo;
4044                                         type = TypeManager.TypeToCoreType (mi.ReturnType);
4045                                         if (!mi.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null))
4046                                                 SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
4047                                 }
4048
4049                                 if ((method as ConstructorInfo) != null)
4050                                 {
4051                                         ConstructorInfo ci = method as ConstructorInfo;
4052                                         type = TypeManager.void_type;
4053                                         if (!ci.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null))
4054                                                 SimpleName.Error_ObjectRefRequired (ec, loc, ci.Name);
4055                                 }
4056
4057                                 if (type.IsPointer)
4058                                 {
4059                                         if (!ec.InUnsafe)
4060                                         {
4061                                                 UnsafeError (loc);
4062                                                 return null;
4063                                         }
4064                                 }
4065                                 eclass = ExprClass.Value;
4066                                 expr_to_return = this;
4067                         }
4068
4069                         if (expr is PropertyExpr)
4070                         {
4071                                 PropertyExpr pe = ((PropertyExpr) expr);
4072                                 pe.PropertyArgs = (ArrayList) Arguments.Clone();
4073                                 Arguments.Clear();
4074                                 Arguments = new ArrayList();
4075                                 MethodBase mi = pe.PropertyInfo.GetGetMethod(true);
4076
4077                                 if(VerifyArgumentsCompat (ec, pe.PropertyArgs,
4078                                         pe.PropertyArgs.Count, mi, false, null, loc, pe.Name))
4079                                 {
4080
4081                                         expr_to_return = pe.DoResolve (ec);
4082                                         expr_to_return.eclass = ExprClass.PropertyAccess;
4083                                 }
4084                                 else
4085                                 {
4086                                         throw new Exception("Error resolving Property Access expression\n" + pe.ToString());
4087                                 }
4088                         }
4089
4090                         if (expr is FieldExpr || expr is LocalVariableReference || expr is ParameterReference) {
4091                                 if (expr.Type.IsArray) {
4092                                         // If we are here, expr must be an ArrayAccess
4093                                         ArrayList idxs = new ArrayList();
4094                                         foreach (Argument a in Arguments)
4095                                         {
4096                                                 idxs.Add (a.Expr);
4097                                         }
4098                                         ElementAccess ea = new ElementAccess (expr, idxs, expr.Location);
4099                                         ArrayAccess aa = new ArrayAccess (ea, expr.Location);
4100                                         expr_to_return = aa.DoResolve(ec);
4101                                         expr_to_return.eclass = ExprClass.Variable;
4102                                 }
4103                                 else
4104                                 {
4105                                         // We can't resolve now, but we
4106                                         // have to try to access the array with a call
4107                                         // to LateIndexGet/Set in the runtime
4108                                         Expression lig_call_expr;
4109
4110                                         if (!is_left_hand)
4111                                                 lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexGet", Location.Null);
4112                                         else
4113                                                 lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexSet", Location.Null);
4114                                         Expression obj_type = Mono.MonoBASIC.Parser.DecomposeQI("System.Object", Location.Null);
4115                                         ArrayList adims = new ArrayList();
4116
4117                                         ArrayList ainit = new ArrayList();
4118                                         foreach (Argument a in Arguments)
4119                                                 ainit.Add ((Expression) a.Expr);
4120
4121                                         adims.Add ((Expression) new IntLiteral (Arguments.Count));
4122
4123                                         Expression oace = new ArrayCreation (obj_type, adims, "", ainit, Location.Null);
4124
4125                                         ArrayList args = new ArrayList();
4126                                         args.Add (new Argument(expr, Argument.AType.Expression));
4127                                         args.Add (new Argument(oace, Argument.AType.Expression));
4128                                         args.Add (new Argument(NullLiteral.Null, Argument.AType.Expression));
4129
4130                                         Expression lig_call = new Invocation (lig_call_expr, args, Location.Null);
4131                                         expr_to_return = lig_call.Resolve(ec);
4132                                         expr_to_return.eclass = ExprClass.Variable;
4133                                 }
4134                         }
4135
4136                         return expr_to_return;
4137                 }
4138
4139         static void Error_WrongNumArguments (Location loc, String name, int arg_count)
4140         {
4141             Report.Error (1501, loc, "No overload for method `" + name + "' takes `" +
4142                                       arg_count + "' arguments");
4143         }
4144
4145                 // <summary>
4146                 //   Emits the list of arguments as an array
4147                 // </summary>
4148                 static void EmitParams (EmitContext ec, int idx, ArrayList arguments)
4149                 {
4150                         ILGenerator ig = ec.ig;
4151                         int count = arguments.Count - idx;
4152                         Argument a = (Argument) arguments [idx];
4153                         Type t = a.Expr.Type;
4154                         string array_type = t.FullName + "[]";
4155                         LocalBuilder array;
4156
4157                         array = ig.DeclareLocal (TypeManager.LookupType (array_type));
4158                         IntConstant.EmitInt (ig, count);
4159                         ig.Emit (OpCodes.Newarr, TypeManager.TypeToCoreType (t));
4160                         ig.Emit (OpCodes.Stloc, array);
4161
4162                         int top = arguments.Count;
4163                         for (int j = idx; j < top; j++){
4164                                 a = (Argument) arguments [j];
4165
4166                                 ig.Emit (OpCodes.Ldloc, array);
4167                                 IntConstant.EmitInt (ig, j - idx);
4168                                 a.Emit (ec);
4169
4170                                 ArrayAccess.EmitStoreOpcode (ig, t);
4171                         }
4172                         ig.Emit (OpCodes.Ldloc, array);
4173                 }
4174
4175                 /// <summary>
4176                 ///   Emits a list of resolved Arguments that are in the arguments
4177                 ///   ArrayList.
4178                 /// </summary>
4179                 public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments)
4180                 {
4181                         ParameterData pd = GetParameterData (mb);
4182
4183                         //
4184                         // If we are calling a params method with no arguments, special case it
4185                         //
4186                         if (arguments == null){
4187                                 if (pd.Count > 0 &&
4188                                     pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
4189                                         ILGenerator ig = ec.ig;
4190
4191                                         IntConstant.EmitInt (ig, 0);
4192                                         ig.Emit (OpCodes.Newarr, pd.ParameterType (0).GetElementType ());
4193                                 }
4194                                 return;
4195                         }
4196
4197                         int top = arguments.Count;
4198
4199                         for (int i = 0; i < top; i++){
4200                                 Argument a = (Argument) arguments [i];
4201
4202                                 if (pd.ParameterModifier (i) == Parameter.Modifier.PARAMS){
4203                                         //
4204                                         // Special case if we are passing the same data as the
4205                                         // params argument, do not put it in an array.
4206                                         //
4207                                         if (pd.ParameterType (i) == a.Type)
4208                                                 a.Emit (ec);
4209                                         else
4210                                                 EmitParams (ec, i, arguments);
4211                                         return;
4212                                 }
4213
4214                                 if ((a.ArgType == Argument.AType.Ref || a.ArgType == Argument.AType.Out) &&
4215                                         !(a.Expr is IMemoryLocation)) {
4216                                         LocalTemporary tmp = new LocalTemporary (ec, pd.ParameterType (i));
4217
4218                                         a.Expr.Emit (ec);
4219                                         tmp.Store (ec);
4220                                         a = new Argument (tmp, a.ArgType);
4221                                 }
4222
4223                                 a.Emit (ec);
4224                         }
4225
4226                         if (pd.Count > top &&
4227                             pd.ParameterModifier (top) == Parameter.Modifier.PARAMS){
4228                                 ILGenerator ig = ec.ig;
4229
4230                                 IntConstant.EmitInt (ig, 0);
4231                                 ig.Emit (OpCodes.Newarr, pd.ParameterType (top).GetElementType ());
4232                         }
4233                 }
4234
4235                 /// <remarks>
4236                 ///   is_base tells whether we want to force the use of the 'call'
4237                 ///   opcode instead of using callvirt.  Call is required to call
4238                 ///   a specific method, while callvirt will always use the most
4239                 ///   recent method in the vtable.
4240                 ///
4241                 ///   is_static tells whether this is an invocation on a static method
4242                 ///
4243                 ///   instance_expr is an expression that represents the instance
4244                 ///   it must be non-null if is_static is false.
4245                 ///
4246                 ///   method is the method to invoke.
4247                 ///
4248                 ///   Arguments is the list of arguments to pass to the method or constructor.
4249                 /// </remarks>
4250                 public static void EmitCall (EmitContext ec, bool is_base,
4251                                              bool is_static, Expression instance_expr,
4252                                              MethodBase method, ArrayList Arguments, Location loc)
4253                 {
4254                         EmitCall (ec, is_base, is_static, instance_expr, method, Arguments, null, loc);
4255                 }
4256
4257                 public static void EmitCall (EmitContext ec, bool is_base,
4258                         bool is_static, Expression instance_expr,
4259                         MethodBase method, ArrayList Arguments, ArrayList prop_args, Location loc)
4260                 {
4261                         ILGenerator ig = ec.ig;
4262                         bool struct_call = false;
4263
4264                         Type decl_type = method.DeclaringType;
4265
4266                         if (!RootContext.StdLib)
4267                         {
4268                                 // Replace any calls to the system's System.Array type with calls to
4269                                 // the newly created one.
4270                                 if (method == TypeManager.system_int_array_get_length)
4271                                         method = TypeManager.int_array_get_length;
4272                                 else if (method == TypeManager.system_int_array_get_rank)
4273                                         method = TypeManager.int_array_get_rank;
4274                                 else if (method == TypeManager.system_object_array_clone)
4275                                         method = TypeManager.object_array_clone;
4276                                 else if (method == TypeManager.system_int_array_get_length_int)
4277                                         method = TypeManager.int_array_get_length_int;
4278                                 else if (method == TypeManager.system_int_array_get_lower_bound_int)
4279                                         method = TypeManager.int_array_get_lower_bound_int;
4280                                 else if (method == TypeManager.system_int_array_get_upper_bound_int)
4281                                         method = TypeManager.int_array_get_upper_bound_int;
4282                                 else if (method == TypeManager.system_void_array_copyto_array_int)
4283                                         method = TypeManager.void_array_copyto_array_int;
4284                         }
4285
4286                         //
4287                         // This checks the 'ConditionalAttribute' on the method, and the
4288                         // ObsoleteAttribute
4289                         //
4290                         TypeManager.MethodFlags flags = TypeManager.GetMethodFlags (method, loc);
4291                         if ((flags & TypeManager.MethodFlags.IsObsoleteError) != 0)
4292                                 return;
4293                         if ((flags & TypeManager.MethodFlags.ShouldIgnore) != 0)
4294                                 return;
4295
4296                         if (!is_static)
4297                         {
4298                                 if (decl_type.IsValueType)
4299                                         struct_call = true;
4300                                 //
4301                                 // If this is ourselves, push "this"
4302                                 //
4303                                 if (instance_expr == null)
4304                                 {
4305                                         ig.Emit (OpCodes.Ldarg_0);
4306                                 }
4307                                 else
4308                                 {
4309                                         //
4310                                         // Push the instance expression
4311                                         //
4312                                         if (instance_expr.Type.IsValueType)
4313                                         {
4314                                                 //
4315                                                 // Special case: calls to a function declared in a
4316                                                 // reference-type with a value-type argument need
4317                                                 // to have their value boxed.
4318
4319                                                 struct_call = true;
4320                                                 if (decl_type.IsValueType)
4321                                                 {
4322                                                         //
4323                                                         // If the expression implements IMemoryLocation, then
4324                                                         // we can optimize and use AddressOf on the
4325                                                         // return.
4326                                                         //
4327                                                         // If not we have to use some temporary storage for
4328                                                         // it.
4329                                                         if (instance_expr is IMemoryLocation)
4330                                                         {
4331                                                                 ((IMemoryLocation)instance_expr).
4332                                                                         AddressOf (ec, AddressOp.LoadStore);
4333                                                         }
4334                                                         else
4335                                                         {
4336                                                                 Type t = instance_expr.Type;
4337
4338                                                                 instance_expr.Emit (ec);
4339                                                                 LocalBuilder temp = ig.DeclareLocal (t);
4340                                                                 ig.Emit (OpCodes.Stloc, temp);
4341                                                                 ig.Emit (OpCodes.Ldloca, temp);
4342                                                         }
4343                                                 }
4344                                                 else
4345                                                 {
4346                                                         instance_expr.Emit (ec);
4347                                                         ig.Emit (OpCodes.Box, instance_expr.Type);
4348                                                 }
4349                                         }
4350                                         else
4351                                                 instance_expr.Emit (ec);
4352                                 }
4353                         }
4354
4355                         if (prop_args != null && prop_args.Count > 0)
4356                         {
4357                                 if (Arguments == null)
4358                                         Arguments = new ArrayList();
4359
4360                                 for (int i = prop_args.Count-1; i >=0 ; i--)
4361                                 {
4362                                         Arguments.Insert (0,prop_args[i]);
4363                                 }
4364
4365                         }
4366
4367                         EmitArguments (ec, method, Arguments);
4368
4369                         if (is_static || struct_call || is_base)
4370                         {
4371                                 if (method is MethodInfo)
4372                                 {
4373                                         ig.Emit (OpCodes.Call, (MethodInfo) method);
4374                                 }
4375                                 else
4376                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4377                         }
4378                         else
4379                         {
4380                                 if (method is MethodInfo)
4381                                         ig.Emit (OpCodes.Callvirt, (MethodInfo) method);
4382                                 else
4383                                         ig.Emit (OpCodes.Callvirt, (ConstructorInfo) method);
4384                         }
4385                 }
4386
4387                 static void EmitPropertyArgs (EmitContext ec, ArrayList prop_args)
4388                 {
4389                         int top = prop_args.Count;
4390
4391                         for (int i = 0; i < top; i++)
4392                         {
4393                                 Argument a = (Argument) prop_args [i];
4394                                 a.Emit (ec);
4395                         }
4396                 }
4397
4398                 public override void Emit (EmitContext ec)
4399                 {
4400                         MethodGroupExpr mg = (MethodGroupExpr) this.expr;
4401
4402                         EmitCall (
4403                                 ec, is_base, method.IsStatic, mg.InstanceExpression, method, Arguments, loc);
4404                 }
4405
4406                 public override void EmitStatement (EmitContext ec)
4407                 {
4408                         Emit (ec);
4409
4410                         //
4411                         // Pop the return value if there is one
4412                         //
4413                         if (method is MethodInfo){
4414                                 Type ret = ((MethodInfo)method).ReturnType;
4415                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
4416                                         ec.ig.Emit (OpCodes.Pop);
4417                         }
4418                 }
4419         }
4420
4421         //
4422         // This class is used to "disable" the code generation for the
4423         // temporary variable when initializing value types.
4424         //
4425         class EmptyAddressOf : EmptyExpression, IMemoryLocation {
4426                 public void AddressOf (EmitContext ec, AddressOp Mode)
4427                 {
4428                         // nothing
4429                 }
4430         }
4431
4432         /// <summary>
4433         ///    Implements the new expression
4434         /// </summary>
4435         public class New : ExpressionStatement {
4436                 public readonly ArrayList Arguments;
4437                 public readonly Expression RequestedType;
4438
4439                 MethodBase method = null;
4440
4441                 //
4442                 // If set, the new expression is for a value_target, and
4443                 // we will not leave anything on the stack.
4444                 //
4445                 Expression value_target;
4446                 bool value_target_set = false;
4447                 public bool isDelegate = false;
4448
4449                 public New (Expression requested_type, ArrayList arguments, Location l)
4450                 {
4451                         RequestedType = requested_type;
4452                         Arguments = arguments;
4453                         loc = l;
4454                 }
4455
4456                 public Expression ValueTypeVariable {
4457                         get {
4458                                 return value_target;
4459                         }
4460
4461                         set {
4462                                 value_target = value;
4463                                 value_target_set = true;
4464                         }
4465                 }
4466
4467                 //
4468                 // This function is used to disable the following code sequence for
4469                 // value type initialization:
4470                 //
4471                 // AddressOf (temporary)
4472                 // Construct/Init
4473                 // LoadTemporary
4474                 //
4475                 // Instead the provide will have provided us with the address on the
4476                 // stack to store the results.
4477                 //
4478                 static Expression MyEmptyExpression;
4479
4480                 public void DisableTemporaryValueType ()
4481                 {
4482                         if (MyEmptyExpression == null)
4483                                 MyEmptyExpression = new EmptyAddressOf ();
4484
4485                         //
4486                         // To enable this, look into:
4487                         // test-34 and test-89 and self bootstrapping.
4488                         //
4489                         // For instance, we can avoid a copy by using 'newobj'
4490                         // instead of Call + Push-temp on value types.
4491 //                      value_target = MyEmptyExpression;
4492                 }
4493
4494                 public override Expression DoResolve (EmitContext ec)
4495                 {
4496                         if (this.isDelegate) {
4497                                 // if its a delegate resolve the type of RequestedType first
4498                                 Expression dtype = RequestedType.Resolve(ec);
4499                                 string ts = (dtype.Type.ToString()).Replace ('+','.');
4500                                 dtype = Mono.MonoBASIC.Parser.DecomposeQI (ts, Location.Null);
4501
4502                                 type = ec.DeclSpace.ResolveType (dtype, false, loc);
4503                         }
4504                         else
4505                                 type = ec.DeclSpace.ResolveType (RequestedType, false, loc);
4506
4507                         if (type == null)
4508                                 return null;
4509
4510                         bool IsDelegate = TypeManager.IsDelegateType (type);
4511
4512                         if (IsDelegate)
4513                                 return (new NewDelegate (type, Arguments, loc)).Resolve (ec);
4514
4515                         if (type.IsInterface || type.IsAbstract){
4516                                 Error (
4517                                         30376, "It is not possible to create instances of Interfaces " +
4518                                         "or classes marked as MustInherit");
4519                                 return null;
4520                         }
4521
4522                         bool is_struct = false;
4523                         is_struct = type.IsValueType;
4524                         eclass = ExprClass.Value;
4525
4526                         //
4527                         // SRE returns a match for .ctor () on structs (the object constructor),
4528                         // so we have to manually ignore it.
4529                         //
4530                         if (is_struct && Arguments == null)
4531                                 return this;
4532
4533                         Expression ml;
4534                         ml = MemberLookupFinal (ec, type, ".ctor",
4535                                                 MemberTypes.Constructor,
4536                                                 AllBindingFlags | BindingFlags.Public, loc);
4537
4538                         if (ml == null)
4539                                 return null;
4540
4541                         if (! (ml is MethodGroupExpr)){
4542                                 if (!is_struct){
4543                                         ml.Error118 ("method group");
4544                                         return null;
4545                                 }
4546                         }
4547
4548                         if (ml != null) {
4549                                 if (Arguments != null){
4550                                         foreach (Argument a in Arguments){
4551                                                 if (!a.Resolve (ec, loc))
4552                                                         return null;
4553                                         }
4554                                 }
4555
4556                                 method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml,
4557                                                                      Arguments, loc);
4558
4559                         }
4560
4561                         if (method == null) {
4562                                 if (!is_struct || Arguments.Count > 0) {
4563                                         Error (1501,
4564                                                "New invocation: Can not find a constructor for " +
4565                                                "this argument list");
4566                                         return null;
4567                                 }
4568                         }
4569                         return this;
4570                 }
4571
4572                 //
4573                 // This DoEmit can be invoked in two contexts:
4574                 //    * As a mechanism that will leave a value on the stack (new object)
4575                 //    * As one that wont (init struct)
4576                 //
4577                 // You can control whether a value is required on the stack by passing
4578                 // need_value_on_stack.  The code *might* leave a value on the stack
4579                 // so it must be popped manually
4580                 //
4581                 // If we are dealing with a ValueType, we have a few
4582                 // situations to deal with:
4583                 //
4584                 //    * The target is a ValueType, and we have been provided
4585                 //      the instance (this is easy, we are being assigned).
4586                 //
4587                 //    * The target of New is being passed as an argument,
4588                 //      to a boxing operation or a function that takes a
4589                 //      ValueType.
4590                 //
4591                 //      In this case, we need to create a temporary variable
4592                 //      that is the argument of New.
4593                 //
4594                 // Returns whether a value is left on the stack
4595                 //
4596                 bool DoEmit (EmitContext ec, bool need_value_on_stack)
4597                 {
4598                         bool is_value_type = type.IsValueType;
4599                         ILGenerator ig = ec.ig;
4600
4601                         if (is_value_type){
4602                                 IMemoryLocation ml;
4603
4604                                 // Allow DoEmit() to be called multiple times.
4605                                 // We need to create a new LocalTemporary each time since
4606                                 // you can't share LocalBuilders among ILGeneators.
4607                                 if (!value_target_set)
4608                                         value_target = new LocalTemporary (ec, type);
4609
4610                                 ml = (IMemoryLocation) value_target;
4611                                 ml.AddressOf (ec, AddressOp.Store);
4612                         }
4613
4614                         if (method != null)
4615                                 Invocation.EmitArguments (ec, method, Arguments);
4616
4617                         if (is_value_type){
4618                                 if (method == null)
4619                                         ig.Emit (OpCodes.Initobj, type);
4620                                 else
4621                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4622                                 if (need_value_on_stack){
4623                                         value_target.Emit (ec);
4624                                         return true;
4625                                 }
4626                                 return false;
4627                         } else {
4628                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) method);
4629                                 return true;
4630                         }
4631                 }
4632
4633                 public override void Emit (EmitContext ec)
4634                 {
4635                         DoEmit (ec, true);
4636                 }
4637
4638                 public override void EmitStatement (EmitContext ec)
4639                 {
4640                         if (DoEmit (ec, false))
4641                                 ec.ig.Emit (OpCodes.Pop);
4642                 }
4643         }
4644
4645         /// <summary>
4646         ///   14.5.10.2: Represents an array creation expression.
4647         /// </summary>
4648         ///
4649         /// <remarks>
4650         ///   There are two possible scenarios here: one is an array creation
4651         ///   expression that specifies the dimensions and optionally the
4652         ///   initialization data and the other which does not need dimensions
4653         ///   specified but where initialization data is mandatory.
4654         /// </remarks>
4655         public class ArrayCreation : ExpressionStatement {
4656                 Expression requested_base_type;
4657                 ArrayList initializers;
4658
4659                 //
4660                 // The list of Argument types.
4661                 // This is used to construct the 'newarray' or constructor signature
4662                 //
4663                 ArrayList arguments;
4664
4665                 //
4666                 // Method used to create the array object.
4667                 //
4668                 MethodBase new_method = null;
4669
4670                 Type array_element_type;
4671                 Type underlying_type;
4672                 bool is_one_dimensional = false;
4673                 bool is_builtin_type = false;
4674                 bool expect_initializers = false;
4675                 int num_arguments = 0;
4676                 int dimensions = 0;
4677                 string rank;
4678
4679                 ArrayList array_data;
4680
4681                 Hashtable bounds;
4682
4683                 //
4684                 // The number of array initializers that we can handle
4685                 // via the InitializeArray method - through EmitStaticInitializers
4686                 //
4687                 int num_automatic_initializers;
4688
4689                 public ArrayCreation (Expression requested_base_type, ArrayList exprs, string rank, ArrayList initializers, Location l)
4690                 {
4691                         this.requested_base_type = requested_base_type;
4692                         this.initializers = initializers;
4693                         this.rank = rank;
4694                         loc = l;
4695
4696                         arguments = new ArrayList ();
4697
4698                         foreach (Expression e in exprs) {
4699                                 arguments.Add (new Argument (e, Argument.AType.Expression));
4700                                 num_arguments++;
4701                         }
4702                 }
4703
4704                 public ArrayCreation (Expression requested_base_type, string rank, ArrayList initializers, Location l)
4705                 {
4706                         this.requested_base_type = requested_base_type;
4707                         this.initializers = initializers;
4708                         this.rank = rank;
4709                         loc = l;
4710
4711                         //this.rank = rank.Substring (0, rank.LastIndexOf ("["));
4712                         //
4713                         //string tmp = rank.Substring (rank.LastIndexOf ("["));
4714                         //
4715                         //dimensions = tmp.Length - 1;
4716                         expect_initializers = true;
4717                 }
4718
4719                 public Expression FormArrayType (Expression base_type, int idx_count, string rank)
4720                 {
4721                         StringBuilder sb = new StringBuilder (rank);
4722
4723                         sb.Append ("[");
4724                         for (int i = 1; i < idx_count; i++)
4725                                 sb.Append (",");
4726
4727                         sb.Append ("]");
4728
4729                         return new ComposedCast (base_type, sb.ToString (), loc);
4730                 }
4731
4732                 void Error_IncorrectArrayInitializer ()
4733                 {
4734                         Error (30567, "Incorrectly structured array initializer");
4735                 }
4736
4737                 public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
4738                 {
4739                         if (specified_dims) {
4740                                 Argument a = (Argument) arguments [idx];
4741
4742                                 if (!a.Resolve (ec, loc))
4743                                         return false;
4744
4745                                 if (!(a.Expr is Constant)) {
4746                                         Error (150, "A constant value is expected");
4747                                         return false;
4748                                 }
4749
4750                                 int value = (int) ((Constant) a.Expr).GetValue ();
4751
4752                                 if (value != probe.Count) {
4753                                         Error_IncorrectArrayInitializer ();
4754                                         return false;
4755                                 }
4756
4757                                 bounds [idx] = value;
4758                         }
4759
4760                         int child_bounds = -1;
4761                         foreach (object o in probe) {
4762                                 if (o is ArrayList) {
4763                                         int current_bounds = ((ArrayList) o).Count;
4764
4765                                         if (child_bounds == -1)
4766                                                 child_bounds = current_bounds;
4767
4768                                         else if (child_bounds != current_bounds){
4769                                                 Error_IncorrectArrayInitializer ();
4770                                                 return false;
4771                                         }
4772                                         bool ret = CheckIndices (ec, (ArrayList) o, idx + 1, specified_dims);
4773                                         if (!ret)
4774                                                 return false;
4775                                 } else {
4776                                         if (child_bounds != -1){
4777                                                 Error_IncorrectArrayInitializer ();
4778                                                 return false;
4779                                         }
4780
4781                                         Expression tmp = (Expression) o;
4782                                         tmp = tmp.Resolve (ec);
4783                                         if (tmp == null)
4784                                                 continue;
4785
4786                                         // Console.WriteLine ("I got: " + tmp);
4787                                         // Handle initialization from vars, fields etc.
4788
4789                                         Expression conv = ConvertImplicitRequired (
4790                                                 ec, tmp, underlying_type, loc);
4791
4792                                         if (conv == null)
4793                                                 return false;
4794
4795                                         if (conv is StringConstant)
4796                                                 array_data.Add (conv);
4797                                         else if (conv is Constant) {
4798                                                 array_data.Add (conv);
4799                                                 num_automatic_initializers++;
4800                                         } else
4801                                                 array_data.Add (conv);
4802                                 }
4803                         }
4804
4805                         return true;
4806                 }
4807
4808                 public void UpdateIndices (EmitContext ec)
4809                 {
4810                         int i = 0;
4811                         for (ArrayList probe = initializers; probe != null;) {
4812                                 if (probe.Count > 0 && probe [0] is ArrayList) {
4813                                         Expression e = new IntConstant (probe.Count);
4814                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4815
4816                                         bounds [i++] =  probe.Count;
4817
4818                                         probe = (ArrayList) probe [0];
4819
4820                                 } else {
4821                                         Expression e = new IntConstant (probe.Count);
4822                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4823
4824                                         bounds [i++] = probe.Count;
4825                                         probe = null;
4826                                 }
4827                         }
4828
4829                 }
4830
4831                 public bool ValidateInitializers (EmitContext ec, Type array_type)
4832                 {
4833                         if (initializers == null) {
4834                                 if (expect_initializers)
4835                                         return false;
4836                                 else
4837                                         return true;
4838                         }
4839
4840                         if (underlying_type == null)
4841                                 return false;
4842
4843                         //
4844                         // We use this to store all the date values in the order in which we
4845                         // will need to store them in the byte blob later
4846                         //
4847                         array_data = new ArrayList ();
4848                         bounds = new Hashtable ();
4849
4850                         bool ret;
4851
4852                         if (arguments != null) {
4853                                 ret = CheckIndices (ec, initializers, 0, true);
4854                                 return ret;
4855                         } else {
4856                                 arguments = new ArrayList ();
4857
4858                                 ret = CheckIndices (ec, initializers, 0, false);
4859
4860                                 if (!ret)
4861                                         return false;
4862
4863                                 UpdateIndices (ec);
4864
4865                                 if (arguments.Count != dimensions) {
4866                                         Error_IncorrectArrayInitializer ();
4867                                         return false;
4868                                 }
4869
4870                                 return ret;
4871                         }
4872                 }
4873
4874                 void Error_NegativeArrayIndex ()
4875                 {
4876                         Error (284, "Can not create array with a negative size");
4877                 }
4878
4879                 //
4880                 // Converts 'source' to an int, uint, long or ulong.
4881                 //
4882                 Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
4883                 {
4884                         Expression target;
4885
4886                         bool old_checked = ec.CheckState;
4887                         ec.CheckState = true;
4888
4889                         target = ConvertImplicit (ec, source, TypeManager.int32_type, loc);
4890                         if (target == null){
4891                                 target = ConvertImplicit (ec, source, TypeManager.uint32_type, loc);
4892                                 if (target == null){
4893                                         target = ConvertImplicit (ec, source, TypeManager.int64_type, loc);
4894                                         if (target == null){
4895                                                 target = ConvertImplicit (ec, source, TypeManager.uint64_type, loc);
4896                                                 if (target == null)
4897                                                         Expression.Error_CannotConvertImplicit (loc, source.Type, TypeManager.int32_type);
4898                                         }
4899                                 }
4900                         }
4901                         ec.CheckState = old_checked;
4902
4903                         //
4904                         // Only positive constants are allowed at compile time
4905                         //
4906                         if (target is Constant){
4907                                 if (target is IntConstant){
4908                                         if (((IntConstant) target).Value < 0){
4909                                                 Error_NegativeArrayIndex ();
4910                                                 return null;
4911                                         }
4912                                 }
4913
4914                                 if (target is LongConstant){
4915                                         if (((LongConstant) target).Value < 0){
4916                                                 Error_NegativeArrayIndex ();
4917                                                 return null;
4918                                         }
4919                                 }
4920
4921                         }
4922
4923                         return target;
4924                 }
4925
4926                 //
4927                 // Creates the type of the array
4928                 //
4929                 bool LookupType (EmitContext ec)
4930                 {
4931                         StringBuilder array_qualifier = new StringBuilder (rank);
4932
4933                         //
4934                         // 'In the first form allocates an array instace of the type that results
4935                         // from deleting each of the individual expression from the expression list'
4936                         //
4937                         if (num_arguments > 0) {
4938                                 array_qualifier.Append ("[");
4939                                 for (int i = num_arguments-1; i > 0; i--)
4940                                         array_qualifier.Append (",");
4941                                 array_qualifier.Append ("]");
4942                         }
4943
4944                         //
4945                         // Lookup the type
4946                         //
4947                         Expression array_type_expr;
4948                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
4949                         string sss = array_qualifier.ToString ();
4950                         type = ec.DeclSpace.ResolveType (array_type_expr, false, loc);
4951
4952                         if (type == null)
4953                                 return false;
4954
4955                         underlying_type = type;
4956                         if (underlying_type.IsArray)
4957                                 underlying_type = TypeManager.TypeToCoreType (underlying_type.GetElementType ());
4958                         dimensions = type.GetArrayRank ();
4959
4960                         return true;
4961                 }
4962
4963                 public override Expression DoResolve (EmitContext ec)
4964                 {
4965                         int arg_count;
4966
4967                         if (!LookupType (ec))
4968                                 return null;
4969
4970                         //
4971                         // First step is to validate the initializers and fill
4972                         // in any missing bits
4973                         //
4974                         if (!ValidateInitializers (ec, type))
4975                                 return null;
4976
4977                         if (arguments == null)
4978                                 arg_count = 0;
4979                         else {
4980                                 arg_count = arguments.Count;
4981                                 foreach (Argument a in arguments){
4982                                         if (!a.Resolve (ec, loc))
4983                                                 return null;
4984
4985                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
4986                                         if (real_arg == null)
4987                                                 return null;
4988
4989                                         a.Expr = real_arg;
4990                                 }
4991                         }
4992
4993                         array_element_type = TypeManager.TypeToCoreType (type.GetElementType ());
4994
4995                         if (arg_count == 1) {
4996                                 is_one_dimensional = true;
4997                                 eclass = ExprClass.Value;
4998                                 return this;
4999                         }
5000
5001                         is_builtin_type = TypeManager.IsBuiltinType (type);
5002
5003                         if (is_builtin_type) {
5004                                 Expression ml;
5005
5006                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
5007                                                    AllBindingFlags, loc);
5008
5009                                 if (!(ml is MethodGroupExpr)) {
5010                                         ml.Error118 ("method group");
5011                                         return null;
5012                                 }
5013
5014                                 if (ml == null) {
5015                                         Error (-6, "New invocation: Can not find a constructor for " +
5016                                                       "this argument list");
5017                                         return null;
5018                                 }
5019
5020                                 new_method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml, arguments, loc);
5021
5022                                 if (new_method == null) {
5023                                         Error (-6, "New invocation: Can not find a constructor for " +
5024                                                       "this argument list");
5025                                         return null;
5026                                 }
5027
5028                                 eclass = ExprClass.Value;
5029                                 return this;
5030                         } else {
5031                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
5032                                 ArrayList args = new ArrayList ();
5033
5034                                 if (arguments != null) {
5035                                         for (int i = 0; i < arg_count; i++)
5036                                                 args.Add (TypeManager.int32_type);
5037                                 }
5038
5039                                 Type [] arg_types = null;
5040
5041                                 if (args.Count > 0)
5042                                         arg_types = new Type [args.Count];
5043
5044                                 args.CopyTo (arg_types, 0);
5045
5046                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
5047                                                             arg_types);
5048
5049                                 if (new_method == null) {
5050                                         Error (-6, "New invocation: Can not find a constructor for " +
5051                                                       "this argument list");
5052                                         return null;
5053                                 }
5054
5055                                 eclass = ExprClass.Value;
5056                                 return this;
5057                         }
5058                 }
5059
5060                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
5061                 {
5062                         int factor;
5063                         byte [] data;
5064                         byte [] element;
5065                         int count = array_data.Count;
5066
5067                         if (underlying_type.IsEnum)
5068                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
5069
5070                         factor = GetTypeSize (underlying_type);
5071                         if (factor == 0)
5072                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
5073
5074                         data = new byte [(count * factor + 4) & ~3];
5075                         int idx = 0;
5076
5077                         for (int i = 0; i < count; ++i) {
5078                                 object v = array_data [i];
5079
5080                                 if (v is EnumConstant)
5081                                         v = ((EnumConstant) v).Child;
5082
5083                                 if (v is Constant && !(v is StringConstant))
5084                                         v = ((Constant) v).GetValue ();
5085                                 else {
5086                                         idx += factor;
5087                                         continue;
5088                                 }
5089
5090                                 if (underlying_type == TypeManager.int64_type){
5091                                         if (!(v is Expression)){
5092                                                 long val = (long) v;
5093
5094                                                 for (int j = 0; j < factor; ++j) {
5095                                                         data [idx + j] = (byte) (val & 0xFF);
5096                                                         val = (val >> 8);
5097                                                 }
5098                                         }
5099                                 } else if (underlying_type == TypeManager.uint64_type){
5100                                         if (!(v is Expression)){
5101                                                 ulong val = (ulong) v;
5102
5103                                                 for (int j = 0; j < factor; ++j) {
5104                                                         data [idx + j] = (byte) (val & 0xFF);
5105                                                         val = (val >> 8);
5106                                                 }
5107                                         }
5108                                 } else if (underlying_type == TypeManager.float_type) {
5109                                         if (!(v is Expression)){
5110                                                 element = BitConverter.GetBytes ((float) v);
5111
5112                                                 for (int j = 0; j < factor; ++j)
5113                                                         data [idx + j] = element [j];
5114                                         }
5115                                 } else if (underlying_type == TypeManager.double_type) {
5116                                         if (!(v is Expression)){
5117                                                 element = BitConverter.GetBytes ((double) v);
5118
5119                                                 for (int j = 0; j < factor; ++j)
5120                                                         data [idx + j] = element [j];
5121                                         }
5122                                 } else if (underlying_type == TypeManager.char_type){
5123                                         if (!(v is Expression)){
5124                                                 int val = (int) ((char) v);
5125
5126                                                 data [idx] = (byte) (val & 0xff);
5127                                                 data [idx+1] = (byte) (val >> 8);
5128                                         }
5129                                 } else if (underlying_type == TypeManager.short_type){
5130                                         if (!(v is Expression)){
5131                                                 int val = (int) ((short) v);
5132
5133                                                 data [idx] = (byte) (val & 0xff);
5134                                                 data [idx+1] = (byte) (val >> 8);
5135                                         }
5136                                 } else if (underlying_type == TypeManager.ushort_type){
5137                                         if (!(v is Expression)){
5138                                                 int val = (int) ((ushort) v);
5139
5140                                                 data [idx] = (byte) (val & 0xff);
5141                                                 data [idx+1] = (byte) (val >> 8);
5142                                         }
5143                                 } else if (underlying_type == TypeManager.int32_type) {
5144                                         if (!(v is Expression)){
5145                                                 int val = (int) v;
5146
5147                                                 data [idx]   = (byte) (val & 0xff);
5148                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
5149                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
5150                                                 data [idx+3] = (byte) (val >> 24);
5151                                         }
5152                                 } else if (underlying_type == TypeManager.uint32_type) {
5153                                         if (!(v is Expression)){
5154                                                 uint val = (uint) v;
5155
5156                                                 data [idx]   = (byte) (val & 0xff);
5157                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
5158                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
5159                                                 data [idx+3] = (byte) (val >> 24);
5160                                         }
5161                                 } else if (underlying_type == TypeManager.sbyte_type) {
5162                                         if (!(v is Expression)){
5163                                                 sbyte val = (sbyte) v;
5164                                                 data [idx] = (byte) val;
5165                                         }
5166                                 } else if (underlying_type == TypeManager.byte_type) {
5167                                         if (!(v is Expression)){
5168                                                 byte val = (byte) v;
5169                                                 data [idx] = (byte) val;
5170                                         }
5171                                 } else if (underlying_type == TypeManager.bool_type) {
5172                                         if (!(v is Expression)){
5173                                                 bool val = (bool) v;
5174                                                 data [idx] = (byte) (val ? 1 : 0);
5175                                         }
5176                                 } else if (underlying_type == TypeManager.decimal_type){
5177                                         if (!(v is Expression)){
5178                                                 int [] bits = Decimal.GetBits ((decimal) v);
5179                                                 int p = idx;
5180
5181                                                 for (int j = 0; j < 4; j++){
5182                                                         data [p++] = (byte) (bits [j] & 0xff);
5183                                                         data [p++] = (byte) ((bits [j] >> 8) & 0xff);
5184                                                         data [p++] = (byte) ((bits [j] >> 16) & 0xff);
5185                                                         data [p++] = (byte) (bits [j] >> 24);
5186                                                 }
5187                                         }
5188                                 } else
5189                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
5190
5191                                 idx += factor;
5192                         }
5193
5194                         return data;
5195                 }
5196
5197                 //
5198                 // Emits the initializers for the array
5199                 //
5200                 void EmitStaticInitializers (EmitContext ec, bool is_expression)
5201                 {
5202                         //
5203                         // First, the static data
5204                         //
5205                         FieldBuilder fb;
5206                         ILGenerator ig = ec.ig;
5207
5208                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
5209
5210                         fb = RootContext.MakeStaticData (data);
5211
5212                         if (is_expression)
5213                                 ig.Emit (OpCodes.Dup);
5214                         ig.Emit (OpCodes.Ldtoken, fb);
5215                         ig.Emit (OpCodes.Call,
5216                                  TypeManager.void_initializearray_array_fieldhandle);
5217                 }
5218
5219                 //
5220                 // Emits pieces of the array that can not be computed at compile
5221                 // time (variables and string locations).
5222                 //
5223                 // This always expect the top value on the stack to be the array
5224                 //
5225                 void EmitDynamicInitializers (EmitContext ec, bool is_expression)
5226                 {
5227                         ILGenerator ig = ec.ig;
5228                         int dims = bounds.Count;
5229                         int [] current_pos = new int [dims];
5230                         int top = array_data.Count;
5231                         LocalBuilder temp = ig.DeclareLocal (type);
5232
5233                         ig.Emit (OpCodes.Stloc, temp);
5234
5235                         MethodInfo set = null;
5236
5237                         if (dims != 1){
5238                                 Type [] args;
5239                                 ModuleBuilder mb = null;
5240                                 mb = CodeGen.ModuleBuilder;
5241                                 args = new Type [dims + 1];
5242
5243                                 int j;
5244                                 for (j = 0; j < dims; j++)
5245                                         args [j] = TypeManager.int32_type;
5246
5247                                 args [j] = array_element_type;
5248
5249                                 set = mb.GetArrayMethod (
5250                                         type, "Set",
5251                                         CallingConventions.HasThis | CallingConventions.Standard,
5252                                         TypeManager.void_type, args);
5253                         }
5254
5255                         for (int i = 0; i < top; i++){
5256
5257                                 Expression e = null;
5258
5259                                 if (array_data [i] is Expression)
5260                                         e = (Expression) array_data [i];
5261
5262                                 if (e != null) {
5263                                         //
5264                                         // Basically we do this for string literals and
5265                                         // other non-literal expressions
5266                                         //
5267                                         if (e is StringConstant || !(e is Constant) ||
5268                                             num_automatic_initializers <= 2) {
5269                                                 Type etype = e.Type;
5270
5271                                                 ig.Emit (OpCodes.Ldloc, temp);
5272
5273                                                 for (int idx = 0; idx < dims; idx++)
5274                                                         IntConstant.EmitInt (ig, current_pos [idx]);
5275
5276                                                 //
5277                                                 // If we are dealing with a struct, get the
5278                                                 // address of it, so we can store it.
5279                                                 //
5280                                                 if ((dims == 1) &&
5281                                                     etype.IsSubclassOf (TypeManager.value_type) &&
5282                                                     (!TypeManager.IsBuiltinType (etype) ||
5283                                                      etype == TypeManager.decimal_type)) {
5284                                                         if (e is New){
5285                                                                 New n = (New) e;
5286
5287                                                                 //
5288                                                                 // Let new know that we are providing
5289                                                                 // the address where to store the results
5290                                                                 //
5291                                                                 n.DisableTemporaryValueType ();
5292                                                         }
5293
5294                                                         ig.Emit (OpCodes.Ldelema, etype);
5295                                                 }
5296
5297                                                 e.Emit (ec);
5298
5299                                                 if (dims == 1)
5300                                                         ArrayAccess.EmitStoreOpcode (ig, array_element_type);
5301                                                 else
5302                                                         ig.Emit (OpCodes.Call, set);
5303                                         }
5304                                 }
5305
5306                                 //
5307                                 // Advance counter
5308                                 //
5309                                 for (int j = dims - 1; j >= 0; j--){
5310                                         current_pos [j]++;
5311                                         if (current_pos [j] < (int) bounds [j])
5312                                                 break;
5313                                         current_pos [j] = 0;
5314                                 }
5315                         }
5316
5317                         if (is_expression)
5318                                 ig.Emit (OpCodes.Ldloc, temp);
5319                 }
5320
5321                 void EmitArrayArguments (EmitContext ec)
5322                 {
5323                         ILGenerator ig = ec.ig;
5324
5325                         foreach (Argument a in arguments) {
5326                                 Type atype = a.Type;
5327                                 a.Emit (ec);
5328
5329                                 if (atype == TypeManager.uint64_type)
5330                                         ig.Emit (OpCodes.Conv_Ovf_U4);
5331                                 else if (atype == TypeManager.int64_type)
5332                                         ig.Emit (OpCodes.Conv_Ovf_I4);
5333                         }
5334                 }
5335
5336                 void DoEmit (EmitContext ec, bool is_statement)
5337                 {
5338                         ILGenerator ig = ec.ig;
5339
5340                         EmitArrayArguments (ec);
5341                         if (is_one_dimensional)
5342                                 ig.Emit (OpCodes.Newarr, array_element_type);
5343                         else {
5344                                 if (is_builtin_type)
5345                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
5346                                 else
5347                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
5348                         }
5349
5350                         if (initializers != null){
5351                                 //
5352                                 // FIXME: Set this variable correctly.
5353                                 //
5354                                 bool dynamic_initializers = true;
5355
5356                                 if (underlying_type != TypeManager.string_type &&
5357                                     underlying_type != TypeManager.object_type) {
5358                                         if (num_automatic_initializers > 2)
5359                                                 EmitStaticInitializers (ec, dynamic_initializers || !is_statement);
5360                                 }
5361
5362                                 if (dynamic_initializers)
5363                                         EmitDynamicInitializers (ec, !is_statement);
5364                         }
5365                 }
5366
5367                 public override void Emit (EmitContext ec)
5368                 {
5369                         DoEmit (ec, false);
5370                 }
5371
5372                 public override void EmitStatement (EmitContext ec)
5373                 {
5374                         DoEmit (ec, true);
5375                 }
5376
5377         }
5378
5379         /// <summary>
5380         ///   Represents the 'this' construct
5381         /// </summary>
5382         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
5383
5384                 Block block;
5385                 VariableInfo vi;
5386
5387                 public This (Block block, Location loc)
5388                 {
5389                         this.loc = loc;
5390                         this.block = block;
5391                 }
5392
5393                 public This (Location loc)
5394                 {
5395                         this.loc = loc;
5396                 }
5397
5398                 public bool IsAssigned (EmitContext ec, Location loc)
5399                 {
5400                         if (vi == null)
5401                                 return true;
5402
5403                         return vi.IsAssigned (ec, loc);
5404                 }
5405
5406                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
5407                 {
5408                         if (vi == null)
5409                                 return true;
5410
5411                         return vi.IsFieldAssigned (ec, field_name, loc);
5412                 }
5413
5414                 public void SetAssigned (EmitContext ec)
5415                 {
5416                         if (vi != null)
5417                                 vi.SetAssigned (ec);
5418                 }
5419
5420                 public void SetFieldAssigned (EmitContext ec, string field_name)
5421                 {
5422                         if (vi != null)
5423                                 vi.SetFieldAssigned (ec, field_name);
5424                 }
5425
5426                 public override Expression DoResolve (EmitContext ec)
5427                 {
5428                         eclass = ExprClass.Variable;
5429                         type = ec.ContainerType;
5430
5431                         if (ec.IsStatic){
5432                                 Error (26, "Keyword this not valid in static code");
5433                                 return null;
5434                         }
5435
5436                         if (block != null)
5437                                 vi = block.ThisVariable;
5438
5439                         return this;
5440                 }
5441
5442                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5443                 {
5444                         DoResolve (ec);
5445
5446                         VariableInfo vi = ec.CurrentBlock.ThisVariable;
5447                         if (vi != null)
5448                                 vi.SetAssigned (ec);
5449
5450                         if (ec.TypeContainer is Class){
5451                                 Error (1604, "Cannot assign to 'this'");
5452                                 return null;
5453                         }
5454
5455                         return this;
5456                 }
5457
5458                 public override void Emit (EmitContext ec)
5459                 {
5460                         ILGenerator ig = ec.ig;
5461
5462                         ig.Emit (OpCodes.Ldarg_0);
5463                         if (ec.TypeContainer is Struct)
5464                                 ig.Emit (OpCodes.Ldobj, type);
5465                 }
5466
5467                 public void EmitAssign (EmitContext ec, Expression source)
5468                 {
5469                         ILGenerator ig = ec.ig;
5470
5471                         if (ec.TypeContainer is Struct){
5472                                 ig.Emit (OpCodes.Ldarg_0);
5473                                 source.Emit (ec);
5474                                 ig.Emit (OpCodes.Stobj, type);
5475                         } else {
5476                                 source.Emit (ec);
5477                                 ig.Emit (OpCodes.Starg, 0);
5478                         }
5479                 }
5480
5481                 public void AddressOf (EmitContext ec, AddressOp mode)
5482                 {
5483                         ec.ig.Emit (OpCodes.Ldarg_0);
5484
5485                         // FIMXE
5486                         // FIGURE OUT WHY LDARG_S does not work
5487                         //
5488                         // consider: struct X { int val; int P { set { val = value; }}}
5489                         //
5490                         // Yes, this looks very bad. Look at 'NOTAS' for
5491                         // an explanation.
5492                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
5493                 }
5494         }
5495
5496         /// <summary>
5497         ///   Implements the typeof operator
5498         /// </summary>
5499         public class TypeOf : Expression {
5500                 public readonly Expression QueriedType;
5501                 Type typearg;
5502
5503                 public TypeOf (Expression queried_type, Location l)
5504                 {
5505                         QueriedType = queried_type;
5506                         loc = l;
5507                 }
5508
5509                 public override Expression DoResolve (EmitContext ec)
5510                 {
5511                         typearg = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5512
5513                         if (typearg == null)
5514                                 return null;
5515
5516                         type = TypeManager.type_type;
5517                         eclass = ExprClass.Type;
5518                         return this;
5519                 }
5520
5521                 public override void Emit (EmitContext ec)
5522                 {
5523                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
5524                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
5525                 }
5526
5527                 public Type TypeArg {
5528                         get { return typearg; }
5529                 }
5530         }
5531
5532         /// <summary>
5533         ///   Implements the sizeof expression
5534         /// </summary>
5535         public class SizeOf : Expression {
5536                 public readonly Expression QueriedType;
5537                 Type type_queried;
5538
5539                 public SizeOf (Expression queried_type, Location l)
5540                 {
5541                         this.QueriedType = queried_type;
5542                         loc = l;
5543                 }
5544
5545                 public override Expression DoResolve (EmitContext ec)
5546                 {
5547                         if (!ec.InUnsafe) {
5548                                 Error (233, "Sizeof may only be used in an unsafe context " +
5549                                        "(consider using System.Runtime.InteropServices.Marshal.Sizeof");
5550                                 return null;
5551                         }
5552
5553                         type_queried = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5554                         if (type_queried == null)
5555                                 return null;
5556
5557                         if (!TypeManager.IsUnmanagedType (type_queried)){
5558                                 Report.Error (208, "Cannot take the size of an unmanaged type (" + TypeManager.MonoBASIC_Name (type_queried) + ")");
5559                                 return null;
5560                         }
5561
5562                         type = TypeManager.int32_type;
5563                         eclass = ExprClass.Value;
5564                         return this;
5565                 }
5566
5567                 public override void Emit (EmitContext ec)
5568                 {
5569                         int size = GetTypeSize (type_queried);
5570
5571                         if (size == 0)
5572                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
5573                         else
5574                                 IntConstant.EmitInt (ec.ig, size);
5575                 }
5576         }
5577
5578         /// <summary>
5579         ///   Implements the member access expression
5580         /// </summary>
5581         public class MemberAccess : Expression, ITypeExpression {
5582                 public readonly string Identifier;
5583                 Expression expr;
5584                 Expression member_lookup;
5585
5586                 public MemberAccess (Expression expr, string id, Location l)
5587                 {
5588                         this.expr = expr;
5589                         Identifier = id;
5590                         loc = l;
5591                 }
5592
5593                 public Expression Expr {
5594                         get {
5595                                 return expr;
5596                         }
5597                 }
5598
5599                 static void error176 (Location loc, string name)
5600                 {
5601                         Report.Error (176, loc, "Static member '" +
5602                                       name + "' cannot be accessed " +
5603                                       "with an instance reference, qualify with a " +
5604                                       "type name instead");
5605                 }
5606
5607                 static bool IdenticalNameAndTypeName (EmitContext ec, Expression left_original, Location loc)
5608                 {
5609                         if (left_original == null)
5610                                 return false;
5611
5612                         if (!(left_original is SimpleName))
5613                                 return false;
5614
5615                         SimpleName sn = (SimpleName) left_original;
5616
5617                         Type t = RootContext.LookupType (ec.DeclSpace, sn.Name, true, loc);
5618                         if (t != null)
5619                                 return true;
5620
5621                         return false;
5622                 }
5623
5624                 public static Expression ResolveMemberAccess (EmitContext ec, Expression member_lookup,
5625                                                               Expression left, Location loc,
5626                                                               Expression left_original)
5627                 {
5628                         bool left_is_type, left_is_explicit;
5629
5630                         // If 'left' is null, then we're called from SimpleNameResolve and this is
5631                         // a member in the currently defining class.
5632                         if (left == null) {
5633                                 left_is_type = ec.IsStatic || ec.IsFieldInitializer;
5634                                 left_is_explicit = false;
5635
5636                                 // Implicitly default to 'this' unless we're static.
5637                                 if (!ec.IsStatic && !ec.IsFieldInitializer && !ec.InEnumContext)
5638                                         left = ec.This;
5639                         } else {
5640                                 left_is_type = left is TypeExpr;
5641                                 left_is_explicit = true;
5642                         }
5643
5644                         if (member_lookup is FieldExpr){
5645                                 FieldExpr fe = (FieldExpr) member_lookup;
5646                                 FieldInfo fi = fe.FieldInfo;
5647                                 Type decl_type = fi.DeclaringType;
5648
5649                                 if (fi is FieldBuilder) {
5650                                         Const c = TypeManager.LookupConstant ((FieldBuilder) fi);
5651
5652                                         if (c != null) {
5653                                                 object o = c.LookupConstantValue (ec);
5654                                                 object real_value = ((Constant) c.Expr).GetValue ();
5655
5656                                                 return Constantify (real_value, fi.FieldType);
5657                                         }
5658                                 }
5659
5660                                 if (fi.IsLiteral) {
5661                                         Type t = fi.FieldType;
5662
5663                                         object o;
5664
5665                                         if (fi is FieldBuilder)
5666                                                 o = TypeManager.GetValue ((FieldBuilder) fi);
5667                                         else
5668                                                 o = fi.GetValue (fi);
5669
5670                                         if (decl_type.IsSubclassOf (TypeManager.enum_type)) {
5671                                                 if (left_is_explicit && !left_is_type &&
5672                                                     !IdenticalNameAndTypeName (ec, left_original, loc)) {
5673                                                         error176 (loc, fe.FieldInfo.Name);
5674                                                         return null;
5675                                                 }
5676
5677                                                 Expression enum_member = MemberLookup (
5678                                                         ec, decl_type, "value__", MemberTypes.Field,
5679                                                         AllBindingFlags, loc);
5680
5681                                                 Enum en = TypeManager.LookupEnum (decl_type);
5682
5683                                                 Constant c;
5684                                                 if (en != null)
5685                                                         c = Constantify (o, en.UnderlyingType);
5686                                                 else
5687                                                         c = Constantify (o, enum_member.Type);
5688
5689                                                 return new EnumConstant (c, decl_type);
5690                                         }
5691
5692                                         Expression exp = Constantify (o, t);
5693
5694                                         if (left_is_explicit && !left_is_type) {
5695                                                 error176 (loc, fe.FieldInfo.Name);
5696                                                 return null;
5697                                         }
5698
5699                                         return exp;
5700                                 }
5701
5702                                 if (fi.FieldType.IsPointer && !ec.InUnsafe){
5703                                         UnsafeError (loc);
5704                                         return null;
5705                                 }
5706                         }
5707
5708                         if (member_lookup is EventExpr) {
5709
5710                                 EventExpr ee = (EventExpr) member_lookup;
5711
5712                                 //
5713                                 // If the event is local to this class, we transform ourselves into
5714                                 // a FieldExpr
5715                                 //
5716
5717                                 if (ee.EventInfo.DeclaringType == ec.ContainerType) {
5718                                         MemberInfo mi = GetFieldFromEvent (ee);
5719
5720                                         if (mi == null) {
5721                                                 //
5722                                                 // If this happens, then we have an event with its own
5723                                                 // accessors and private field etc so there's no need
5724                                                 // to transform ourselves : we should instead flag an error
5725                                                 //
5726                                                 Assign.error70 (ee.EventInfo, loc);
5727                                                 return null;
5728                                         }
5729
5730                                         Expression ml = ExprClassFromMemberInfo (ec, mi, loc);
5731
5732                                         if (ml == null) {
5733                                                 Report.Error (-200, loc, "Internal error!!");
5734                                                 return null;
5735                                         }
5736
5737                                         return ResolveMemberAccess (ec, ml, left, loc, left_original);
5738                                 }
5739                         }
5740
5741                         if (member_lookup is IMemberExpr) {
5742                                 IMemberExpr me = (IMemberExpr) member_lookup;
5743
5744                                 if (left_is_type){
5745                                         MethodGroupExpr mg = me as MethodGroupExpr;
5746                                         if ((mg != null) && left_is_explicit && left.Type.IsInterface)
5747                                                 mg.IsExplicitImpl = left_is_explicit;
5748
5749                                         if (!me.IsStatic){
5750                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5751                                                         return member_lookup;
5752
5753                                                 SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
5754                                                 return null;
5755                                         }
5756
5757                                 } else {
5758                                         if (!me.IsInstance){
5759                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5760                                                         return member_lookup;
5761
5762                                                 /*if (left_is_explicit) {
5763                                                         error176 (loc, me.Name);
5764                                                         return null;
5765                                                 }*/
5766                                         }
5767
5768                                         //
5769                                         // Since we can not check for instance objects in SimpleName,
5770                                         // becaue of the rule that allows types and variables to share
5771                                         // the name (as long as they can be de-ambiguated later, see
5772                                         // IdenticalNameAndTypeName), we have to check whether left
5773                                         // is an instance variable in a static context
5774                                         //
5775                                         // However, if the left-hand value is explicitly given, then
5776                                         // it is already our instance expression, so we aren't in
5777                                         // static context.
5778                                         //
5779
5780                                         if (ec.IsStatic && !left_is_explicit && left is IMemberExpr){
5781                                                 IMemberExpr mexp = (IMemberExpr) left;
5782
5783                                                 if (!mexp.IsStatic){
5784                                                         SimpleName.Error_ObjectRefRequired (ec, loc, mexp.Name);
5785                                                         return null;
5786                                                 }
5787                                         }
5788
5789                                         me.InstanceExpression = left;
5790                                 }
5791
5792                                 return member_lookup;
5793                         }
5794
5795                         if (member_lookup is TypeExpr){
5796                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5797                                 return member_lookup;
5798                         }
5799
5800                         Console.WriteLine ("Left is: " + left);
5801                         Report.Error (-100, loc, "Support for [" + member_lookup + "] is not present yet");
5802                         Environment.Exit (0);
5803                         return null;
5804                 }
5805
5806                 public Expression DoResolve (EmitContext ec, Expression right_side, ResolveFlags flags)
5807                 {
5808                         if (type != null)
5809                                 throw new Exception ();
5810                         //
5811                         // Resolve the expression with flow analysis turned off, we'll do the definite
5812                         // assignment checks later.  This is because we don't know yet what the expression
5813                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
5814                         // definite assignment check on the actual field and not on the whole struct.
5815                         //
5816
5817                         Expression original = expr;
5818                         expr = expr.Resolve (ec, flags | ResolveFlags.DisableFlowAnalysis);
5819
5820                         if (expr == null)
5821                                 return null;
5822
5823                         if (expr is SimpleName){
5824                                 SimpleName child_expr = (SimpleName) expr;
5825
5826                                 Expression new_expr = new SimpleName (child_expr.Name + "." + Identifier, loc);
5827
5828                                 if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
5829                                         return new_expr.Resolve (ec, flags);
5830                                 else
5831                                         return new_expr.Resolve (ec, flags | ResolveFlags.MethodGroup | ResolveFlags.VariableOrValue);
5832                         }
5833
5834                         int errors = Report.Errors;
5835
5836                         Type expr_type = expr.Type;
5837
5838                         if (expr is TypeExpr){
5839                                 //FIXME: add access level check
5840                                 //if (!ec.DeclSpace.CheckAccessLevel (expr_type)) {
5841                                 //              Error (30390, "'" + TypeManager.MonoBASIC_Name (expr_type) + "' " +
5842                                 //                     "is inaccessible because of its protection level");
5843                                 //      return null;
5844                                 //}
5845
5846                                 if (expr_type == TypeManager.enum_type || expr_type.IsSubclassOf (TypeManager.enum_type)){
5847                                         Enum en = TypeManager.LookupEnum (expr_type);
5848
5849                                         if (en != null) {
5850                                                 object value = en.LookupEnumValue (ec, Identifier, loc);
5851
5852                                                 if (value != null){
5853                                                         Constant c = Constantify (value, en.UnderlyingType);
5854                                                         return new EnumConstant (c, expr_type);
5855                                                 }
5856                                         }
5857                                 }
5858                         }
5859
5860                         if (expr_type.IsPointer){
5861                                 Error (23, "The '.' operator can not be applied to pointer operands (" +
5862                                        TypeManager.MonoBASIC_Name (expr_type) + ")");
5863                                 return null;
5864                         }
5865
5866                         member_lookup = MemberLookup (ec, expr_type, Identifier, loc);
5867
5868                         if (member_lookup == null)
5869                         {
5870                                 // Error has already been reported.
5871                                 if (errors < Report.Errors)
5872                                         return null;
5873
5874                                 //
5875                                 // Try looking the member up from the same type, if we find
5876                                 // it, we know that the error was due to limited visibility
5877                                 //
5878                                 object lookup = TypeManager.MemberLookup (
5879                                         expr_type, expr_type, AllMemberTypes, AllBindingFlags |
5880                                         BindingFlags.NonPublic, Identifier);
5881
5882                                 if (lookup == null)
5883                                         Error (30456, "'" + expr_type + "' does not contain a definition for '" + Identifier + "'");
5884                                 else
5885                                 {
5886                                         if ((expr_type != ec.ContainerType) &&
5887                                                  ec.ContainerType.IsSubclassOf (expr_type))
5888                                         {
5889
5890                                                 // Although a derived class can access protected members of
5891                                                 // its base class it cannot do so through an instance of the
5892                                                 // base class (CS1540).  If the expr_type is a parent of the
5893                                                 // ec.ContainerType and the lookup succeeds with the latter one,
5894                                                 // then we are in this situation.
5895
5896                                                 lookup = TypeManager.MemberLookup(
5897                                                                         ec.ContainerType, ec.ContainerType, AllMemberTypes,
5898                                                                         AllBindingFlags, Identifier);
5899
5900                                                 if (lookup != null)
5901                                                         Error (1540, "Cannot access protected member '" +
5902                                                        expr_type + "." + Identifier + "' " +
5903                                                        "via a qualifier of type '" + TypeManager.MonoBASIC_Name (expr_type) + "'; the " +
5904                                                        "qualifier must be of type '" + TypeManager.MonoBASIC_Name (ec.ContainerType) + "' " +
5905                                                        "(or derived from it)");
5906                                                 else
5907                                                         Error (30390, "'" + expr_type + "." + Identifier + "' " +
5908                                                        "is inaccessible because of its protection level");
5909                                         } else
5910                                                 Error (30390, "'" + expr_type + "." + Identifier + "' " +
5911                                                "is inaccessible because of its protection level");
5912                                 }
5913                                 return null;
5914                         }
5915
5916                         if ((expr is TypeExpr) && (expr_type.IsSubclassOf (TypeManager.enum_type)))     {
5917                                 Enum en = TypeManager.LookupEnum (expr_type);
5918
5919                                 if (en != null) {
5920                                         object value = en.LookupEnumValue (ec, Identifier, loc);
5921                                         expr_type = TypeManager.int32_type;
5922                                         if (value != null) {
5923                                                 Constant c = Constantify (value, en.UnderlyingType);
5924                                                 return new EnumConstant (c, en.UnderlyingType);
5925                                         }
5926                                 }
5927                         }
5928
5929                         if (member_lookup is TypeExpr){
5930                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5931
5932                                 return member_lookup;
5933                         } else if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
5934                                 return null;
5935
5936                         member_lookup = ResolveMemberAccess (ec, member_lookup, expr, loc, original);
5937                         if (member_lookup == null)
5938                                 return null;
5939
5940                         // The following DoResolve/DoResolveLValue will do the definite assignment
5941                         // check.
5942                         if (right_side != null)
5943                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
5944                         else
5945                                 member_lookup = member_lookup.DoResolve (ec);
5946
5947                         return member_lookup;
5948                 }
5949
5950                 public override Expression DoResolve (EmitContext ec)
5951                 {
5952                         return DoResolve (ec, null, ResolveFlags.VariableOrValue |
5953                                           ResolveFlags.SimpleName | ResolveFlags.Type);
5954                 }
5955
5956                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5957                 {
5958                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue |
5959                                           ResolveFlags.SimpleName | ResolveFlags.Type);
5960                 }
5961
5962                 public Expression DoResolveType (EmitContext ec)
5963                 {
5964                         return DoResolve (ec, null, ResolveFlags.Type);
5965                 }
5966
5967                 public override void Emit (EmitContext ec)
5968                 {
5969                         throw new Exception ("Should not happen");
5970                 }
5971
5972                 public override string ToString ()
5973                 {
5974                         return expr + "." + Identifier;
5975                 }
5976         }
5977
5978
5979
5980         /// <summary>
5981         ///   Implements checked expressions
5982         /// </summary>
5983         public class CheckedExpr : Expression {
5984
5985                 public Expression Expr;
5986
5987                 public CheckedExpr (Expression e, Location l)
5988                 {
5989                         Expr = e;
5990                         loc = l;
5991                 }
5992
5993                 public override Expression DoResolve (EmitContext ec)
5994                 {
5995                         bool last_const_check = ec.ConstantCheckState;
5996
5997                         ec.ConstantCheckState = true;
5998                         Expr = Expr.Resolve (ec);
5999                         ec.ConstantCheckState = last_const_check;
6000
6001                         if (Expr == null)
6002                                 return null;
6003
6004                         if (Expr is Constant)
6005                                 return Expr;
6006
6007                         eclass = Expr.eclass;
6008                         type = Expr.Type;
6009                         return this;
6010                 }
6011
6012                 public override void Emit (EmitContext ec)
6013                 {
6014                         bool last_check = ec.CheckState;
6015                         bool last_const_check = ec.ConstantCheckState;
6016
6017                         ec.CheckState = true;
6018                         ec.ConstantCheckState = true;
6019                         Expr.Emit (ec);
6020                         ec.CheckState = last_check;
6021                         ec.ConstantCheckState = last_const_check;
6022                 }
6023
6024         }
6025
6026         /// <summary>
6027         ///   Implements the unchecked expression
6028         /// </summary>
6029         public class UnCheckedExpr : Expression {
6030
6031                 public Expression Expr;
6032
6033                 public UnCheckedExpr (Expression e, Location l)
6034                 {
6035                         Expr = e;
6036                         loc = l;
6037                 }
6038
6039                 public override Expression DoResolve (EmitContext ec)
6040                 {
6041                         bool last_const_check = ec.ConstantCheckState;
6042
6043                         ec.ConstantCheckState = false;
6044                         Expr = Expr.Resolve (ec);
6045                         ec.ConstantCheckState = last_const_check;
6046
6047                         if (Expr == null)
6048                                 return null;
6049
6050                         if (Expr is Constant)
6051                                 return Expr;
6052
6053                         eclass = Expr.eclass;
6054                         type = Expr.Type;
6055                         return this;
6056                 }
6057
6058                 public override void Emit (EmitContext ec)
6059                 {
6060                         bool last_check = ec.CheckState;
6061                         bool last_const_check = ec.ConstantCheckState;
6062
6063                         ec.CheckState = false;
6064                         ec.ConstantCheckState = false;
6065                         Expr.Emit (ec);
6066                         ec.CheckState = last_check;
6067                         ec.ConstantCheckState = last_const_check;
6068                 }
6069
6070         }
6071
6072         /// <summary>
6073         ///   An Element Access expression.
6074         ///
6075         ///   During semantic analysis these are transformed into
6076         ///   IndexerAccess or ArrayAccess
6077         /// </summary>
6078         public class ElementAccess : Expression {
6079                 public ArrayList  Arguments;
6080                 public Expression Expr;
6081
6082                 public ElementAccess (Expression e, ArrayList e_list, Location l)
6083                 {
6084                         Expr = e;
6085
6086                         loc  = l;
6087
6088                         if (e_list == null)
6089                                 return;
6090
6091                         Arguments = new ArrayList ();
6092                         foreach (Expression tmp in e_list)
6093                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
6094
6095                 }
6096
6097                 bool CommonResolve (EmitContext ec)
6098                 {
6099                         Expr = Expr.Resolve (ec);
6100
6101                         if (Expr == null)
6102                                 return false;
6103
6104                         if (Arguments == null)
6105                                 return false;
6106
6107                         foreach (Argument a in Arguments){
6108                                 if (!a.Resolve (ec, loc))
6109                                         return false;
6110                         }
6111
6112                         return true;
6113                 }
6114
6115                 Expression MakePointerAccess ()
6116                 {
6117                         Type t = Expr.Type;
6118
6119                         if (t == TypeManager.void_ptr_type){
6120                                 Error (
6121                                         242,
6122                                         "The array index operation is not valid for void pointers");
6123                                 return null;
6124                         }
6125                         if (Arguments.Count != 1){
6126                                 Error (
6127                                         196,
6128                                         "A pointer must be indexed by a single value");
6129                                 return null;
6130                         }
6131                         Expression p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr,
6132                                                               t, loc);
6133                         return new Indirection (p, loc);
6134                 }
6135
6136                 public override Expression DoResolve (EmitContext ec)
6137                 {
6138                         if (!CommonResolve (ec))
6139                                 return null;
6140
6141                         //
6142                         // We perform some simple tests, and then to "split" the emit and store
6143                         // code we create an instance of a different class, and return that.
6144                         //
6145                         // I am experimenting with this pattern.
6146                         //
6147                         Type t = Expr.Type;
6148
6149                         if (t.IsArray)
6150                                 return (new ArrayAccess (this, loc)).Resolve (ec);
6151                         else if (t.IsPointer)
6152                                 return MakePointerAccess ();
6153                         else
6154                                 return (new IndexerAccess (this, loc)).Resolve (ec);
6155                 }
6156
6157                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6158                 {
6159                         if (!CommonResolve (ec))
6160                                 return null;
6161
6162                         Type t = Expr.Type;
6163                         if (t.IsArray)
6164                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
6165                         else if (t.IsPointer)
6166                                 return MakePointerAccess ();
6167                         else
6168                                 return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
6169                 }
6170
6171                 public override void Emit (EmitContext ec)
6172                 {
6173                         throw new Exception ("Should never be reached");
6174                 }
6175         }
6176
6177         /// <summary>
6178         ///   Implements array access
6179         /// </summary>
6180         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
6181                 //
6182                 // Points to our "data" repository
6183                 //
6184                 ElementAccess ea;
6185
6186                 LocalTemporary [] cached_locations;
6187
6188                 public ArrayAccess (ElementAccess ea_data, Location l)
6189                 {
6190                         ea = ea_data;
6191                         eclass = ExprClass.Variable;
6192                         loc = l;
6193                 }
6194
6195                 public override Expression DoResolve (EmitContext ec)
6196                 {
6197                         ExprClass eclass = ea.Expr.eclass;
6198
6199 #if false
6200                         // As long as the type is valid
6201                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
6202                               eclass == ExprClass.Value)) {
6203                                 ea.Expr.Error118 ("variable or value");
6204                                 return null;
6205                         }
6206 #endif
6207
6208                         Type t = ea.Expr.Type;
6209 /*
6210                         if (t == typeof (System.Object))
6211                         {
6212                                 // We can't resolve now, but we
6213                                 // have to try to access the array with a call
6214                                 // to LateIndexGet in the runtime
6215
6216                                 Expression lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexGet", Location.Null);
6217                                 Expression obj_type = Mono.MonoBASIC.Parser.DecomposeQI("System.Object", Location.Null);
6218                                 ArrayList adims = new ArrayList();
6219
6220                                 ArrayList ainit = new ArrayList();
6221                                 foreach (Argument a in ea.Arguments)
6222                                         ainit.Add ((Expression) a.Expr);
6223
6224                                 adims.Add ((Expression) new IntLiteral (ea.Arguments.Count));
6225
6226                                 Expression oace = new ArrayCreation (obj_type, adims, "", ainit, Location.Null);
6227
6228                                 ArrayList args = new ArrayList();
6229                                 args.Add (new Argument(ea.Expr, Argument.AType.Expression));
6230                                 args.Add (new Argument(oace, Argument.AType.Expression));
6231                                 args.Add (new Argument(NullLiteral.Null, Argument.AType.Expression));
6232
6233                                 Expression lig_call = new Invocation (lig_call_expr, args, Location.Null);
6234                                 lig_call = lig_call.Resolve(ec);
6235                                 return lig_call;
6236                         }
6237 */
6238                         if (t.GetArrayRank () != ea.Arguments.Count){
6239                                 ea.Error (22,
6240                                           "Incorrect number of indexes for array " +
6241                                           " expected: " + t.GetArrayRank () + " got: " +
6242                                           ea.Arguments.Count);
6243                                 return null;
6244                         }
6245                         type = TypeManager.TypeToCoreType (t.GetElementType ());
6246                         if (type.IsPointer && !ec.InUnsafe){
6247                                 UnsafeError (ea.Location);
6248                                 return null;
6249                         }
6250
6251                         foreach (Argument a in ea.Arguments){
6252                                 Type argtype = a.Type;
6253
6254                                 if (argtype == TypeManager.int32_type ||
6255                                     argtype == TypeManager.uint32_type ||
6256                                     argtype == TypeManager.int64_type ||
6257                                     argtype == TypeManager.uint64_type)
6258                                         continue;
6259
6260                                 //
6261                                 // Mhm.  This is strage, because the Argument.Type is not the same as
6262                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
6263                                 //
6264                                 // Wonder if I will run into trouble for this.
6265                                 //
6266                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
6267                                 if (a.Expr == null)
6268                                         return null;
6269                         }
6270
6271                         eclass = ExprClass.Variable;
6272
6273                         return this;
6274                 }
6275
6276                 /// <summary>
6277                 ///    Emits the right opcode to load an object of Type 't'
6278                 ///    from an array of T
6279                 /// </summary>
6280                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
6281                 {
6282                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
6283                                 ig.Emit (OpCodes.Ldelem_U1);
6284                         else if (type == TypeManager.sbyte_type)
6285                                 ig.Emit (OpCodes.Ldelem_I1);
6286                         else if (type == TypeManager.short_type)
6287                                 ig.Emit (OpCodes.Ldelem_I2);
6288                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
6289                                 ig.Emit (OpCodes.Ldelem_U2);
6290                         else if (type == TypeManager.int32_type)
6291                                 ig.Emit (OpCodes.Ldelem_I4);
6292                         else if (type == TypeManager.uint32_type)
6293                                 ig.Emit (OpCodes.Ldelem_U4);
6294                         else if (type == TypeManager.uint64_type)
6295                                 ig.Emit (OpCodes.Ldelem_I8);
6296                         else if (type == TypeManager.int64_type)
6297                                 ig.Emit (OpCodes.Ldelem_I8);
6298                         else if (type == TypeManager.float_type)
6299                                 ig.Emit (OpCodes.Ldelem_R4);
6300                         else if (type == TypeManager.double_type)
6301                                 ig.Emit (OpCodes.Ldelem_R8);
6302                         else if (type == TypeManager.intptr_type)
6303                                 ig.Emit (OpCodes.Ldelem_I);
6304                         else if (type.IsValueType){
6305                                 ig.Emit (OpCodes.Ldelema, type);
6306                                 ig.Emit (OpCodes.Ldobj, type);
6307                         } else
6308                                 ig.Emit (OpCodes.Ldelem_Ref);
6309                 }
6310
6311                 /// <summary>
6312                 ///    Emits the right opcode to store an object of Type 't'
6313                 ///    from an array of T.
6314                 /// </summary>
6315                 static public void EmitStoreOpcode (ILGenerator ig, Type t)
6316                 {
6317                         t = TypeManager.TypeToCoreType (t);
6318                         if (TypeManager.IsEnumType (t) && t != TypeManager.enum_type)
6319                                 t = TypeManager.EnumToUnderlying (t);
6320                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
6321                             t == TypeManager.bool_type)
6322                                 ig.Emit (OpCodes.Stelem_I1);
6323                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type || t == TypeManager.char_type)
6324                                 ig.Emit (OpCodes.Stelem_I2);
6325                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
6326                                 ig.Emit (OpCodes.Stelem_I4);
6327                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
6328                                 ig.Emit (OpCodes.Stelem_I8);
6329                         else if (t == TypeManager.float_type)
6330                                 ig.Emit (OpCodes.Stelem_R4);
6331                         else if (t == TypeManager.double_type)
6332                                 ig.Emit (OpCodes.Stelem_R8);
6333                         else if (t == TypeManager.intptr_type)
6334                                 ig.Emit (OpCodes.Stelem_I);
6335                         else if (t.IsValueType){
6336                                 ig.Emit (OpCodes.Stobj, t);
6337                         } else
6338                                 ig.Emit (OpCodes.Stelem_Ref);
6339                 }
6340
6341                 MethodInfo FetchGetMethod ()
6342                 {
6343                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6344                         int arg_count = ea.Arguments.Count;
6345                         Type [] args = new Type [arg_count];
6346                         MethodInfo get;
6347
6348                         for (int i = 0; i < arg_count; i++){
6349                                 //args [i++] = a.Type;
6350                                 args [i] = TypeManager.int32_type;
6351                         }
6352
6353                         get = mb.GetArrayMethod (
6354                                 ea.Expr.Type, "Get",
6355                                 CallingConventions.HasThis |
6356                                 CallingConventions.Standard,
6357                                 type, args);
6358                         return get;
6359                 }
6360
6361
6362                 MethodInfo FetchAddressMethod ()
6363                 {
6364                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6365                         int arg_count = ea.Arguments.Count;
6366                         Type [] args = new Type [arg_count];
6367                         MethodInfo address;
6368                         string ptr_type_name;
6369                         Type ret_type;
6370
6371                         ptr_type_name = type.FullName + "&";
6372                         ret_type = Type.GetType (ptr_type_name);
6373
6374                         //
6375                         // It is a type defined by the source code we are compiling
6376                         //
6377                         if (ret_type == null){
6378                                 ret_type = mb.GetType (ptr_type_name);
6379                         }
6380
6381                         for (int i = 0; i < arg_count; i++){
6382                                 //args [i++] = a.Type;
6383                                 args [i] = TypeManager.int32_type;
6384                         }
6385
6386                         address = mb.GetArrayMethod (
6387                                 ea.Expr.Type, "Address",
6388                                 CallingConventions.HasThis |
6389                                 CallingConventions.Standard,
6390                                 ret_type, args);
6391
6392                         return address;
6393                 }
6394
6395                 //
6396                 // Load the array arguments into the stack.
6397                 //
6398                 // If we have been requested to cache the values (cached_locations array
6399                 // initialized), then load the arguments the first time and store them
6400                 // in locals.  otherwise load from local variables.
6401                 //
6402                 void LoadArrayAndArguments (EmitContext ec)
6403                 {
6404                         ILGenerator ig = ec.ig;
6405
6406                         if (cached_locations == null){
6407                                 ea.Expr.Emit (ec);
6408                                 foreach (Argument a in ea.Arguments){
6409                                         Type argtype = a.Expr.Type;
6410
6411                                         a.Expr.Emit (ec);
6412
6413                                         if (argtype == TypeManager.int64_type)
6414                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6415                                         else if (argtype == TypeManager.uint64_type)
6416                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6417                                 }
6418                                 return;
6419                         }
6420
6421                         if (cached_locations [0] == null){
6422                                 cached_locations [0] = new LocalTemporary (ec, ea.Expr.Type);
6423                                 ea.Expr.Emit (ec);
6424                                 ig.Emit (OpCodes.Dup);
6425                                 cached_locations [0].Store (ec);
6426
6427                                 int j = 1;
6428
6429                                 foreach (Argument a in ea.Arguments){
6430                                         Type argtype = a.Expr.Type;
6431
6432                                         cached_locations [j] = new LocalTemporary (ec, TypeManager.intptr_type /* a.Expr.Type */);
6433                                         a.Expr.Emit (ec);
6434                                         if (argtype == TypeManager.int64_type)
6435                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6436                                         else if (argtype == TypeManager.uint64_type)
6437                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6438
6439                                         ig.Emit (OpCodes.Dup);
6440                                         cached_locations [j].Store (ec);
6441                                         j++;
6442                                 }
6443                                 return;
6444                         }
6445
6446                         foreach (LocalTemporary lt in cached_locations)
6447                                 lt.Emit (ec);
6448                 }
6449
6450                 public new void CacheTemporaries (EmitContext ec)
6451                 {
6452                         cached_locations = new LocalTemporary [ea.Arguments.Count + 1];
6453                 }
6454
6455                 public override void Emit (EmitContext ec)
6456                 {
6457                         int rank = ea.Expr.Type.GetArrayRank ();
6458                         ILGenerator ig = ec.ig;
6459
6460                         LoadArrayAndArguments (ec);
6461
6462                         if (rank == 1)
6463                                 EmitLoadOpcode (ig, type);
6464                         else {
6465                                 MethodInfo method;
6466
6467                                 method = FetchGetMethod ();
6468                                 ig.Emit (OpCodes.Call, method);
6469                         }
6470                 }
6471
6472                 public void EmitAssign (EmitContext ec, Expression source)
6473                 {
6474                         int rank = ea.Expr.Type.GetArrayRank ();
6475                         ILGenerator ig = ec.ig;
6476                         Type t = source.Type;
6477
6478                         LoadArrayAndArguments (ec);
6479
6480                         //
6481                         // The stobj opcode used by value types will need
6482                         // an address on the stack, not really an array/array
6483                         // pair
6484                         //
6485                         if (rank == 1){
6486                                 if (t == TypeManager.enum_type || t == TypeManager.decimal_type ||
6487                                     (t.IsSubclassOf (TypeManager.value_type) && !TypeManager.IsEnumType (t) && !TypeManager.IsBuiltinType (t)))
6488                                         ig.Emit (OpCodes.Ldelema, t);
6489                         }
6490
6491                         source.Emit (ec);
6492
6493                         if (rank == 1)
6494                                 EmitStoreOpcode (ig, t);
6495                         else {
6496                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
6497                                 int arg_count = ea.Arguments.Count;
6498                                 Type [] args = new Type [arg_count + 1];
6499                                 MethodInfo set;
6500
6501                                 for (int i = 0; i < arg_count; i++){
6502                                         //args [i++] = a.Type;
6503                                         args [i] = TypeManager.int32_type;
6504                                 }
6505
6506                                 args [arg_count] = type;
6507
6508                                 set = mb.GetArrayMethod (
6509                                         ea.Expr.Type, "Set",
6510                                         CallingConventions.HasThis |
6511                                         CallingConventions.Standard,
6512                                         TypeManager.void_type, args);
6513
6514                                 ig.Emit (OpCodes.Call, set);
6515                         }
6516                 }
6517
6518                 public void AddressOf (EmitContext ec, AddressOp mode)
6519                 {
6520                         int rank = ea.Expr.Type.GetArrayRank ();
6521                         ILGenerator ig = ec.ig;
6522
6523                         LoadArrayAndArguments (ec);
6524
6525                         if (rank == 1){
6526                                 ig.Emit (OpCodes.Ldelema, type);
6527                         } else {
6528                                 MethodInfo address = FetchAddressMethod ();
6529                                 ig.Emit (OpCodes.Call, address);
6530                         }
6531                 }
6532         }
6533
6534
6535         class Indexers {
6536                 public ArrayList getters, setters;
6537                 static Hashtable map;
6538
6539                 static Indexers ()
6540                 {
6541                         map = new Hashtable ();
6542                 }
6543
6544                 Indexers (MemberInfo [] mi)
6545                 {
6546                         foreach (PropertyInfo property in mi){
6547                                 MethodInfo get, set;
6548
6549                                 get = property.GetGetMethod (true);
6550                                 if (get != null){
6551                                         if (getters == null)
6552                                                 getters = new ArrayList ();
6553
6554                                         getters.Add (get);
6555                                 }
6556
6557                                 set = property.GetSetMethod (true);
6558                                 if (set != null){
6559                                         if (setters == null)
6560                                                 setters = new ArrayList ();
6561                                         setters.Add (set);
6562                                 }
6563                         }
6564                 }
6565
6566                 static private Indexers GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
6567                 {
6568                         Indexers ix = (Indexers) map [lookup_type];
6569
6570                         if (ix != null)
6571                                 return ix;
6572
6573                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
6574
6575                         MemberInfo [] mi = TypeManager.MemberLookup (
6576                                 caller_type, lookup_type, MemberTypes.Property,
6577                                 BindingFlags.Public | BindingFlags.Instance, p_name);
6578
6579                         if (mi == null || mi.Length == 0)
6580                                 return null;
6581
6582                         ix = new Indexers (mi);
6583                         map [lookup_type] = ix;
6584
6585                         return ix;
6586                 }
6587
6588                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
6589                 {
6590                         Indexers ix = (Indexers) map [lookup_type];
6591
6592                         if (ix != null)
6593                                 return ix;
6594
6595                         ix = GetIndexersForTypeOrInterface (caller_type, lookup_type);
6596                         if (ix != null)
6597                                 return ix;
6598
6599                         Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
6600                         if (ifaces != null) {
6601                                 foreach (Type itype in ifaces) {
6602                                         ix = GetIndexersForTypeOrInterface (caller_type, itype);
6603                                         if (ix != null)
6604                                                 return ix;
6605                                 }
6606                         }
6607
6608                         Report.Error (21, loc,
6609                                       "Type '" + TypeManager.MonoBASIC_Name (lookup_type) +
6610                                       "' does not have any indexers defined");
6611                         return null;
6612                 }
6613         }
6614
6615         /// <summary>
6616         ///   Expressions that represent an indexer call.
6617         /// </summary>
6618         public class IndexerAccess : Expression, IAssignMethod {
6619                 //
6620                 // Points to our "data" repository
6621                 //
6622                 MethodInfo get, set;
6623                 Indexers ilist;
6624                 ArrayList set_arguments;
6625                 bool is_base_indexer;
6626
6627                 protected Type indexer_type;
6628                 protected Type current_type;
6629                 protected Expression instance_expr;
6630                 protected ArrayList arguments;
6631
6632                 public IndexerAccess (ElementAccess ea, Location loc)
6633                         : this (ea.Expr, false, loc)
6634                 {
6635                         this.arguments = ea.Arguments;
6636                 }
6637
6638                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
6639                                          Location loc)
6640                 {
6641                         this.instance_expr = instance_expr;
6642                         this.is_base_indexer = is_base_indexer;
6643                         this.eclass = ExprClass.Value;
6644                         this.loc = loc;
6645                 }
6646
6647                 protected virtual bool CommonResolve (EmitContext ec)
6648                 {
6649                         indexer_type = instance_expr.Type;
6650                         current_type = ec.ContainerType;
6651
6652                         return true;
6653                 }
6654
6655                 public override Expression DoResolve (EmitContext ec)
6656                 {
6657                         if (!CommonResolve (ec))
6658                                 return null;
6659
6660                         //
6661                         // Step 1: Query for all 'Item' *properties*.  Notice
6662                         // that the actual methods are pointed from here.
6663                         //
6664                         // This is a group of properties, piles of them.
6665
6666                         if (ilist == null)
6667                                 ilist = Indexers.GetIndexersForType (
6668                                         current_type, indexer_type, loc);
6669
6670                         //
6671                         // Step 2: find the proper match
6672                         //
6673                         if (ilist != null && ilist.getters != null && ilist.getters.Count > 0)
6674                                 get = (MethodInfo) Invocation.OverloadResolve (
6675                                         ec, new MethodGroupExpr (ilist.getters, loc), arguments, loc);
6676
6677                         if (get == null){
6678                                 Error (154, "indexer can not be used in this context, because " +
6679                                        "it lacks a 'get' accessor");
6680                                 return null;
6681                         }
6682
6683                         type = get.ReturnType;
6684                         if (type.IsPointer && !ec.InUnsafe){
6685                                 UnsafeError (loc);
6686                                 return null;
6687                         }
6688
6689                         eclass = ExprClass.IndexerAccess;
6690                         return this;
6691                 }
6692
6693                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6694                 {
6695                         if (!CommonResolve (ec))
6696                                 return null;
6697
6698                         Type right_type = right_side.Type;
6699
6700                         if (ilist == null)
6701                                 ilist = Indexers.GetIndexersForType (
6702                                         current_type, indexer_type, loc);
6703
6704                         if (ilist != null && ilist.setters != null && ilist.setters.Count > 0){
6705                                 set_arguments = (ArrayList) arguments.Clone ();
6706                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
6707
6708                                 set = (MethodInfo) Invocation.OverloadResolve (
6709                                         ec, new MethodGroupExpr (ilist.setters, loc), set_arguments, loc);
6710                         }
6711
6712                         if (set == null){
6713                                 Error (200, "indexer X.this [" + TypeManager.MonoBASIC_Name (right_type) +
6714                                        "] lacks a 'set' accessor");
6715                                 return null;
6716                         }
6717
6718                         type = TypeManager.void_type;
6719                         eclass = ExprClass.IndexerAccess;
6720                         return this;
6721                 }
6722
6723                 public override void Emit (EmitContext ec)
6724                 {
6725                         Invocation.EmitCall (ec, false, false, instance_expr, get, arguments, loc);
6726                 }
6727
6728                 //
6729                 // source is ignored, because we already have a copy of it from the
6730                 // LValue resolution and we have already constructed a pre-cached
6731                 // version of the arguments (ea.set_arguments);
6732                 //
6733                 public void EmitAssign (EmitContext ec, Expression source)
6734                 {
6735                         Invocation.EmitCall (ec, false, false, instance_expr, set, set_arguments, loc);
6736                 }
6737         }
6738
6739         /// <summary>
6740         ///   The base operator for method names
6741         /// </summary>
6742         public class BaseAccess : Expression {
6743                 public string member;
6744
6745                 public BaseAccess (string member, Location l)
6746                 {
6747                         this.member = member;
6748                         loc = l;
6749                 }
6750
6751                 public override Expression DoResolve (EmitContext ec)
6752                 {
6753                         Expression member_lookup;
6754                         Type current_type = ec.ContainerType;
6755                         Type base_type = current_type.BaseType;
6756                         Expression e;
6757
6758                         if (ec.IsStatic){
6759                                 Error (1511, "Keyword MyBase is not allowed in static method");
6760                                 return null;
6761                         }
6762
6763                         if (member == "New")
6764                                 member = ".ctor";
6765
6766                         member_lookup = MemberLookup (ec, current_type, base_type, member,
6767                                                       AllMemberTypes, AllBindingFlags, loc);
6768
6769                         if (member_lookup == null) {
6770                                 Error (30456,
6771                                               TypeManager.MonoBASIC_Name (base_type) + " does not " +
6772                                               "contain a definition for '" + member + "'");
6773                                 return null;
6774                         }
6775
6776                         Expression left;
6777
6778                         if (ec.IsStatic)
6779                                 left = new TypeExpr (base_type, loc);
6780                         else
6781                                 left = ec.This;
6782
6783                         e = MemberAccess.ResolveMemberAccess (ec, member_lookup, left, loc, null);
6784
6785                         if (e is PropertyExpr){
6786                                 PropertyExpr pe = (PropertyExpr) e;
6787
6788                                 pe.IsBase = true;
6789                         }
6790
6791                         return e;
6792                 }
6793
6794                 public override void Emit (EmitContext ec)
6795                 {
6796                         throw new Exception ("Should never be called");
6797                 }
6798         }
6799
6800         /// <summary>
6801         ///   The base indexer operator
6802         /// </summary>
6803         public class BaseIndexerAccess : IndexerAccess {
6804                 public BaseIndexerAccess (ArrayList args, Location loc)
6805                         : base (null, true, loc)
6806                 {
6807                         arguments = new ArrayList ();
6808                         foreach (Expression tmp in args)
6809                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
6810                 }
6811
6812                 protected override bool CommonResolve (EmitContext ec)
6813                 {
6814                         instance_expr = ec.This;
6815
6816                         current_type = ec.ContainerType.BaseType;
6817                         indexer_type = current_type;
6818
6819                         foreach (Argument a in arguments){
6820                                 if (!a.Resolve (ec, loc))
6821                                         return false;
6822                         }
6823
6824                         return true;
6825                 }
6826         }
6827
6828         /// <summary>
6829         ///   This class exists solely to pass the Type around and to be a dummy
6830         ///   that can be passed to the conversion functions (this is used by
6831         ///   foreach implementation to typecast the object return value from
6832         ///   get_Current into the proper type.  All code has been generated and
6833         ///   we only care about the side effect conversions to be performed
6834         ///
6835         ///   This is also now used as a placeholder where a no-action expression
6836         ///   is needed (the 'New' class).
6837         /// </summary>
6838         public class EmptyExpression : Expression {
6839                 public EmptyExpression ()
6840                 {
6841                         type = TypeManager.object_type;
6842                         eclass = ExprClass.Value;
6843                         loc = Location.Null;
6844                 }
6845
6846                 public EmptyExpression (Type t)
6847                 {
6848                         type = t;
6849                         eclass = ExprClass.Value;
6850                         loc = Location.Null;
6851                 }
6852
6853                 public override Expression DoResolve (EmitContext ec)
6854                 {
6855                         return this;
6856                 }
6857
6858                 public override void Emit (EmitContext ec)
6859                 {
6860                         // nothing, as we only exist to not do anything.
6861                 }
6862
6863                 //
6864                 // This is just because we might want to reuse this bad boy
6865                 // instead of creating gazillions of EmptyExpressions.
6866                 // (CanConvertImplicit uses it)
6867                 //
6868                 public void SetType (Type t)
6869                 {
6870                         type = t;
6871                 }
6872         }
6873
6874         public class UserCast : Expression {
6875                 MethodBase method;
6876                 Expression source;
6877
6878                 public UserCast (MethodInfo method, Expression source, Location l)
6879                 {
6880                         this.method = method;
6881                         this.source = source;
6882                         type = method.ReturnType;
6883                         eclass = ExprClass.Value;
6884                         loc = l;
6885                 }
6886
6887                 public override Expression DoResolve (EmitContext ec)
6888                 {
6889                         //
6890                         // We are born fully resolved
6891                         //
6892                         return this;
6893                 }
6894
6895                 public override void Emit (EmitContext ec)
6896                 {
6897                         ILGenerator ig = ec.ig;
6898
6899                         source.Emit (ec);
6900
6901                         if (method is MethodInfo)
6902                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
6903                         else
6904                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
6905
6906                 }
6907         }
6908
6909         // <summary>
6910         //   This class is used to "construct" the type during a typecast
6911         //   operation.  Since the Type.GetType class in .NET can parse
6912         //   the type specification, we just use this to construct the type
6913         //   one bit at a time.
6914         // </summary>
6915         public class ComposedCast : Expression, ITypeExpression {
6916                 Expression left;
6917                 string dim;
6918
6919                 public ComposedCast (Expression left, string dim, Location l)
6920                 {
6921                         this.left = left;
6922                         this.dim = dim;
6923                         loc = l;
6924                 }
6925
6926                 public Expression DoResolveType (EmitContext ec)
6927                 {
6928                         Type ltype = ec.DeclSpace.ResolveType (left, false, loc);
6929                         if (ltype == null)
6930                                 return null;
6931
6932                         //
6933                         // ltype.Fullname is already fully qualified, so we can skip
6934                         // a lot of probes, and go directly to TypeManager.LookupType
6935                         //
6936                         string cname = ltype.FullName + dim;
6937                         type = TypeManager.LookupTypeDirect (cname);
6938                         if (type == null){
6939                                 //
6940                                 // For arrays of enumerations we are having a problem
6941                                 // with the direct lookup.  Need to investigate.
6942                                 //
6943                                 // For now, fall back to the full lookup in that case.
6944                                 //
6945                                 type = RootContext.LookupType (
6946                                         ec.DeclSpace, cname, false, loc);
6947
6948                                 if (type == null)
6949                                         return null;
6950                         }
6951
6952                         if (!ec.ResolvingTypeTree){
6953                                 //
6954                                 // If the above flag is set, this is being invoked from the ResolveType function.
6955                                 // Upper layers take care of the type validity in this context.
6956                                 //
6957                         if (!ec.InUnsafe && type.IsPointer){
6958                                 UnsafeError (loc);
6959                                 return null;
6960                         }
6961                         }
6962
6963                         eclass = ExprClass.Type;
6964                         return this;
6965                 }
6966
6967                 public override Expression DoResolve (EmitContext ec)
6968                 {
6969                         return DoResolveType (ec);
6970                 }
6971
6972                 public override void Emit (EmitContext ec)
6973                 {
6974                         throw new Exception ("This should never be called");
6975                 }
6976
6977                 public override string ToString ()
6978                 {
6979                         return left + dim;
6980                 }
6981         }
6982
6983         //
6984         // This class is used to represent the address of an array, used
6985         // only by the Fixed statement, this is like the C "&a [0]" construct.
6986         //
6987         public class ArrayPtr : Expression {
6988                 Expression array;
6989
6990                 public ArrayPtr (Expression array, Location l)
6991                 {
6992                         Type array_type = array.Type.GetElementType ();
6993
6994                         this.array = array;
6995
6996                         string array_ptr_type_name = array_type.FullName + "*";
6997
6998                         type = Type.GetType (array_ptr_type_name);
6999                         if (type == null){
7000                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
7001
7002                                 type = mb.GetType (array_ptr_type_name);
7003                         }
7004
7005                         eclass = ExprClass.Value;
7006                         loc = l;
7007                 }
7008
7009                 public override void Emit (EmitContext ec)
7010                 {
7011                         ILGenerator ig = ec.ig;
7012
7013                         array.Emit (ec);
7014                         IntLiteral.EmitInt (ig, 0);
7015                         ig.Emit (OpCodes.Ldelema, array.Type.GetElementType ());
7016                 }
7017
7018                 public override Expression DoResolve (EmitContext ec)
7019                 {
7020                         //
7021                         // We are born fully resolved
7022                         //
7023                         return this;
7024                 }
7025         }
7026
7027         //
7028         // Used by the fixed statement
7029         //
7030         public class StringPtr : Expression {
7031                 LocalBuilder b;
7032
7033                 public StringPtr (LocalBuilder b, Location l)
7034                 {
7035                         this.b = b;
7036                         eclass = ExprClass.Value;
7037                         type = TypeManager.char_ptr_type;
7038                         loc = l;
7039                 }
7040
7041                 public override Expression DoResolve (EmitContext ec)
7042                 {
7043                         // This should never be invoked, we are born in fully
7044                         // initialized state.
7045
7046                         return this;
7047                 }
7048
7049                 public override void Emit (EmitContext ec)
7050                 {
7051                         ILGenerator ig = ec.ig;
7052
7053                         ig.Emit (OpCodes.Ldloc, b);
7054                         ig.Emit (OpCodes.Conv_I);
7055                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
7056                         ig.Emit (OpCodes.Add);
7057                 }
7058         }
7059
7060         //
7061         // Implements the 'stackalloc' keyword
7062         //
7063         public class StackAlloc : Expression {
7064                 Type otype;
7065                 Expression t;
7066                 Expression count;
7067
7068                 public StackAlloc (Expression type, Expression count, Location l)
7069                 {
7070                         t = type;
7071                         this.count = count;
7072                         loc = l;
7073                 }
7074
7075                 public override Expression DoResolve (EmitContext ec)
7076                 {
7077                         count = count.Resolve (ec);
7078                         if (count == null)
7079                                 return null;
7080
7081                         if (count.Type != TypeManager.int32_type){
7082                                 count = ConvertImplicitRequired (ec, count, TypeManager.int32_type, loc);
7083                                 if (count == null)
7084                                         return null;
7085                         }
7086
7087                         if (ec.InCatch || ec.InFinally){
7088                                 Error (255,
7089                                               "stackalloc can not be used in a catch or finally block");
7090                                 return null;
7091                         }
7092
7093                         otype = ec.DeclSpace.ResolveType (t, false, loc);
7094
7095                         if (otype == null)
7096                                 return null;
7097
7098                         if (!TypeManager.VerifyUnManaged (otype, loc))
7099                                 return null;
7100
7101                         string ptr_name = otype.FullName + "*";
7102                         type = Type.GetType (ptr_name);
7103                         if (type == null){
7104                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
7105
7106                                 type = mb.GetType (ptr_name);
7107                         }
7108                         eclass = ExprClass.Value;
7109
7110                         return this;
7111                 }
7112
7113                 public override void Emit (EmitContext ec)
7114                 {
7115                         int size = GetTypeSize (otype);
7116                         ILGenerator ig = ec.ig;
7117
7118                         if (size == 0)
7119                                 ig.Emit (OpCodes.Sizeof, otype);
7120                         else
7121                                 IntConstant.EmitInt (ig, size);
7122                         count.Emit (ec);
7123                         ig.Emit (OpCodes.Mul);
7124                         ig.Emit (OpCodes.Localloc);
7125                 }
7126         }
7127 }