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
3205                                 ReflectionParameters rp = new ReflectionParameters (pi);
3206                                 method_parameter_cache [mb] = rp;
3207
3208                                 return (ParameterData) rp;
3209                         }
3210                 }
3211
3212                 enum Applicability { Same, Better, Worse };
3213
3214                 /// <summary>
3215                 ///  Determines "Better function"
3216                 /// </summary>
3217                 /// <remarks>
3218                 ///    and returns an integer indicating :
3219                 ///    0 if candidate ain't better
3220                 ///    1 if candidate is better than the current best match
3221                 /// </remarks>
3222                 static Applicability BetterFunction (EmitContext ec, ArrayList args,
3223                                             MethodBase candidate, MethodBase best,
3224                                             bool expanded_form, Location loc)
3225                 {
3226                         ParameterData candidate_pd = GetParameterData (candidate);
3227                         ParameterData best_pd;
3228                         int argument_count;
3229
3230                         if (args == null)
3231                                 argument_count = 0;
3232                         else
3233                                 argument_count = args.Count;
3234
3235                         int cand_count = candidate_pd.Count;
3236
3237                         if (cand_count == 0 && argument_count == 0)
3238                                 return Applicability.Same;
3239
3240                         if (candidate_pd.ParameterModifier (cand_count - 1) != Parameter.Modifier.PARAMS)
3241                                 if (cand_count != argument_count)
3242                                         return Applicability.Worse;
3243
3244                         best_pd = GetParameterData (best);
3245
3246                         Applicability res = Applicability.Same;
3247
3248                         for (int j = 0; j < argument_count; ++j) {
3249                                 int x, y;
3250
3251                                 Argument a = (Argument) args [j];
3252
3253                                 Type ct = candidate_pd.ParameterType (j);
3254                                 Type bt = best_pd.ParameterType (j);
3255
3256                                 if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3257                                         if (expanded_form)
3258                                                 ct = ct.GetElementType ();
3259
3260                                 if (best_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3261                                         if (expanded_form)
3262                                                 bt = bt.GetElementType ();
3263
3264                                 if (ct != bt) {
3265                                         if (!WideningConversionExists (ct, bt))
3266                                                 return Applicability.Worse;
3267                                         res = Applicability.Better;
3268                                 }
3269                         }
3270
3271                         if (res == Applicability.Same)
3272                                 if (candidate_pd.Count < best_pd.Count)
3273                                         res = Applicability.Better;
3274                                 else if (candidate_pd.Count > best_pd.Count)
3275                                         res = Applicability.Worse;
3276
3277                         return res;
3278                 }
3279
3280                 public static string FullMethodDesc (MethodBase mb)
3281                 {
3282                         string ret_type = "";
3283
3284                         if (mb is MethodInfo)
3285                                 ret_type = TypeManager.MonoBASIC_Name (((MethodInfo) mb).ReturnType) + " ";
3286
3287                         StringBuilder sb = new StringBuilder (ret_type + mb.Name);
3288                         ParameterData pd = GetParameterData (mb);
3289
3290                         int count = pd.Count;
3291                         sb.Append (" (");
3292
3293                         for (int i = count; i > 0; ) {
3294                                 i--;
3295
3296                                 sb.Append (pd.ParameterDesc (count - i - 1));
3297                                 if (i != 0)
3298                                         sb.Append (", ");
3299                         }
3300
3301                         sb.Append (")");
3302                         return sb.ToString ();
3303                 }
3304
3305                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3306                 {
3307                         MemberInfo [] miset;
3308                         MethodGroupExpr union;
3309
3310                         if (mg1 == null){
3311                                 if (mg2 == null)
3312                                         return null;
3313                                 return (MethodGroupExpr) mg2;
3314                         } else {
3315                                 if (mg2 == null)
3316                                         return (MethodGroupExpr) mg1;
3317                         }
3318
3319                         MethodGroupExpr left_set = null, right_set = null;
3320                         int length1 = 0, length2 = 0;
3321
3322                         left_set = (MethodGroupExpr) mg1;
3323                         length1 = left_set.Methods.Length;
3324
3325                         right_set = (MethodGroupExpr) mg2;
3326                         length2 = right_set.Methods.Length;
3327
3328                         ArrayList common = new ArrayList ();
3329
3330                         foreach (MethodBase l in left_set.Methods){
3331                                 foreach (MethodBase r in right_set.Methods){
3332                                         if (l != r)
3333                                                 continue;
3334                                         common.Add (r);
3335                                         break;
3336                                 }
3337                         }
3338
3339                         miset = new MemberInfo [length1 + length2 - common.Count];
3340                         left_set.Methods.CopyTo (miset, 0);
3341
3342                         int k = length1;
3343
3344                         foreach (MemberInfo mi in right_set.Methods){
3345                                 if (!common.Contains (mi))
3346                                         miset [k++] = mi;
3347                         }
3348
3349                         union = new MethodGroupExpr (miset, loc);
3350
3351                         return union;
3352                 }
3353
3354                 /// <summary>
3355                 ///  Determines is the candidate method, if a params method, is applicable
3356                 ///  in its expanded form to the given set of arguments
3357                 /// </summary>
3358                 static bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments, MethodBase candidate)
3359                 {
3360                         int arg_count;
3361
3362                         if (arguments == null)
3363                                 arg_count = 0;
3364                         else
3365                                 arg_count = arguments.Count;
3366
3367                         ParameterData pd = GetParameterData (candidate);
3368
3369                         int pd_count = pd.Count;
3370
3371                         if (pd_count == 0)
3372                                 return false;
3373
3374                         if (pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS)
3375                                 return false;
3376
3377                         if (pd_count - 1 > arg_count)
3378                                 return false;
3379
3380                         if (pd_count == 1 && arg_count == 0)
3381                                 return true;
3382
3383                         //
3384                         // If we have come this far, the case which remains is when the number of parameters
3385                         // is less than or equal to the argument count.
3386                         //
3387                         for (int i = 0; i < pd_count - 1; ++i) {
3388
3389                                 Argument a = (Argument) arguments [i];
3390
3391                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3392                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3393                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3394                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3395
3396                                 if (a_mod == p_mod) {
3397
3398                                         if (a_mod == Parameter.Modifier.NONE)
3399                                                 if (!ImplicitConversionExists (ec, a.Expr, pd.ParameterType (i)))
3400                                                         return false;
3401
3402                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3403                                                 Type pt = pd.ParameterType (i);
3404
3405                                                 if (!pt.IsByRef)
3406                                                         pt = TypeManager.LookupType (pt.FullName + "&");
3407
3408                                                 if (pt != a.Type)
3409                                                         return false;
3410                                         }
3411                                 } else
3412                                         return false;
3413
3414                         }
3415
3416                         Type element_type = pd.ParameterType (pd_count - 1).GetElementType ();
3417
3418                         for (int i = pd_count - 1; i < arg_count; i++) {
3419                                 Argument a = (Argument) arguments [i];
3420
3421                                 if (!StandardConversionExists (a.Expr, element_type))
3422                                         return false;
3423                         }
3424
3425                         return true;
3426                 }
3427
3428
3429                 protected enum ConversionType { None, Widening, Narrowing };
3430
3431                 static ConversionType CheckParameterAgainstArgument (EmitContext ec, ParameterData pd, int i, Argument a, Type ptype)
3432                 {
3433                         Parameter.Modifier a_mod = a.GetParameterModifier () &
3434                                 ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3435                         Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3436                                 ~(Parameter.Modifier.OUT | Parameter.Modifier.REF | Parameter.Modifier.OPTIONAL);
3437
3438                         if (a_mod == p_mod ||
3439                                 (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
3440                                 if (a_mod == Parameter.Modifier.NONE) {
3441                                         if (! WideningConversionExists (a.Expr, ptype) ) {
3442                                                 if (! NarrowingConversionExists (ec, a.Expr, ptype) )
3443                                                         return ConversionType.None;
3444                                                 else
3445                                                         return ConversionType.Narrowing;
3446                                         } else
3447                                                         return ConversionType.Widening;
3448                                 }
3449
3450                                 if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3451                                         Type pt = pd.ParameterType (i);
3452
3453                                         if (!pt.IsByRef)
3454                                                 pt = TypeManager.LookupType (pt.FullName + "&");
3455
3456                                         if (pt != a.Type)
3457                                                 return ConversionType.None;
3458                                 }
3459                                 return ConversionType.Widening;
3460                         } else
3461                                 return ConversionType.None;
3462                 }
3463
3464                 static bool HasArrayParameter (ParameterData pd)
3465                 {
3466                         int c = pd.Count;
3467                         return c > 0 && (pd.ParameterModifier (c - 1) & Parameter.Modifier.PARAMS) != 0;
3468                 }
3469
3470                 static int CountStandardParams (ParameterData pd)
3471                 {
3472                         int count = pd.Count;
3473                         for (int i = 0; i < count; i++) {
3474                                 Parameter.Modifier pm = pd.ParameterModifier (i);
3475                                 if ((pm & (Parameter.Modifier.OPTIONAL | Parameter.Modifier.PARAMS)) != 0)
3476                                         return i;
3477                         }
3478                         return count;
3479                 }
3480
3481                 /// <summary>
3482                 ///  Determines if the candidate method is applicable (section 14.4.2.1)
3483                 ///  to the given set of arguments
3484                 /// </summary>
3485                 static ConversionType IsApplicable (EmitContext ec, ArrayList arguments, MethodBase candidate, out bool expanded)
3486                 {
3487                         int arg_count, po_count;
3488                         Type param_type;
3489
3490                         expanded = false;
3491
3492                         if (arguments == null)
3493                                 arg_count = 0;
3494                         else
3495                                 arg_count = arguments.Count;
3496
3497                         ParameterData pd = GetParameterData (candidate);
3498                         int ps_count = CountStandardParams (pd);
3499                         int pd_count = pd.Count;
3500
3501                         // Validate argument count
3502                         if (ps_count == pd_count) {
3503                                 if (arg_count != pd_count)
3504                                         return ConversionType.None;
3505                         }
3506                         else {
3507                                 if (arg_count < ps_count)
3508                                         return ConversionType.None;
3509                                 if (!HasArrayParameter (pd) && arg_count > pd_count)
3510                                         return ConversionType.None;
3511                         }
3512                         ConversionType result = ConversionType.Widening;
3513                         ArrayList newarglist = new ArrayList();
3514                         if (arg_count > 0) {
3515                                 result = ConversionType.None;
3516                                 int array_param_index = -1;
3517                                 for (int i = 0; i < arg_count; ++i) {
3518                                         Argument a = (Argument) arguments [i];
3519                                         param_type = pd.ParameterType (i);
3520                                         Parameter.Modifier mod = pd.ParameterModifier (i);
3521                                         if (array_param_index < 0 && (mod & Parameter.Modifier.PARAMS) != 0)
3522                                                 array_param_index = i;
3523
3524                                         bool IsDelegate = TypeManager.IsDelegateType (param_type);
3525
3526                                         if (IsDelegate) {
3527                                                 if (a.ArgType == Argument.AType.AddressOf) {
3528                                                         a = new Argument ((Expression) a.Expr, Argument.AType.Expression);
3529                                                         ArrayList args = new ArrayList();
3530                                                         args.Add (a);
3531                                                         string param_name = pd.ParameterDesc(i).Replace('+', '.');
3532                                                         Expression pname = MonoBASIC.Parser.DecomposeQI (param_name, Location.Null);
3533
3534                                                         New temp_new = new New ((Expression)pname, args, Location.Null);
3535                                                         Expression del_temp = temp_new.DoResolve(ec);
3536
3537                                                         if (del_temp == null)
3538                                                                 return ConversionType.None;
3539
3540                                                         a = new Argument (del_temp, Argument.AType.Expression);
3541                                                         if (!a.Resolve(ec, Location.Null))
3542                                                                 return ConversionType.None;
3543                                                 }
3544                                         }
3545                                         else {
3546                                                 if (a.ArgType == Argument.AType.AddressOf)
3547                                                         return ConversionType.None;
3548                                         }
3549
3550                                         if ((mod & Parameter.Modifier.REF) != 0) {
3551                                                 a = new Argument (a.Expr, Argument.AType.Ref);
3552                                                 if (!a.Resolve(ec,Location.Null))
3553                                                         return ConversionType.None;
3554                                         }
3555
3556                                         ConversionType match = ConversionType.None;
3557                                         if (i == array_param_index)
3558                                                 match = CheckParameterAgainstArgument (ec, pd, i, a, param_type);
3559                                         if (match == ConversionType.None && array_param_index >= 0 && i >= array_param_index) {
3560                                                 expanded = true;
3561                                                 param_type = param_type.GetElementType ();
3562                                         }
3563                                         if (match == ConversionType.None)
3564                                                 match = CheckParameterAgainstArgument (ec, pd, i, a, param_type);
3565                                         newarglist.Add (a);
3566                                         if (match == ConversionType.None)
3567                                                 return ConversionType.None;
3568                                         if (result == ConversionType.None)
3569                                                 result = match;
3570                                         else if (match == ConversionType.Narrowing)
3571                                                 result = ConversionType.Narrowing;
3572                                 }
3573                         }
3574
3575 #if false
3576                         // We've found a candidate, so we exchange the dummy NoArg arguments
3577                         // with new arguments containing the default value for that parameter
3578
3579                         ArrayList newarglist = new ArrayList();
3580                         for (int i = 0; i < arg_count; i++) {
3581                                 Argument a = (Argument) arguments [i];
3582                                 Parameter p = null;
3583
3584                                 if (ps != null)
3585                                         p = (Parameter) ps.FixedParameters[i];
3586
3587                                 if (a.ArgType == Argument.AType.NoArg){
3588                                         a = new Argument (p.ParameterInitializer, Argument.AType.Expression);
3589                                         a.Resolve(ec, Location.Null);
3590                                 }
3591
3592                                 // ToDo - This part is getting resolved second time within this function
3593                                 // This is a costly operation
3594                                 // The earlier resoved result should be used here.
3595                                 // Has to be done during compiler optimization.
3596                                 if (a.ArgType == Argument.AType.AddressOf) {
3597                                         param_type = pd.ParameterType (i);
3598                                         bool IsDelegate = TypeManager.IsDelegateType (param_type);
3599
3600                                         a = new Argument ((Expression) a.Expr, Argument.AType.Expression);
3601                                         ArrayList args = new ArrayList();
3602                                         args.Add (a);
3603                                         string param_name = pd.ParameterDesc(i).Replace('+', '.');
3604                                         Expression pname = MonoBASIC.Parser.DecomposeQI (param_name, Location.Null);
3605
3606                                         New temp_new = new New ((Expression)pname, args, Location.Null);
3607                                         Expression del_temp = temp_new.DoResolve(ec);
3608
3609                                         if (del_temp == null)
3610                                                 return ConversionType.None;
3611
3612                                         a = new Argument (del_temp, Argument.AType.Expression);
3613                                         if (!a.Resolve(ec, Location.Null))
3614                                                 return ConversionType.None;
3615                                 }
3616
3617                                 if ((p != null) && ((p.ModFlags & Parameter.Modifier.REF) != 0)) {
3618                                         a.ArgType = Argument.AType.Ref;
3619                                         a.Resolve(ec, Location.Null);
3620                                 } else if ((pd.ParameterModifier (i) & Parameter.Modifier.REF) != 0) {
3621                                         a.ArgType = Argument.AType.Ref;
3622                                         a.Resolve(ec, Location.Null);
3623                                 }
3624                                 newarglist.Add(a);
3625                                 int n = pd_count - arg_count;
3626                                 if (n > 0) {
3627                                         for (int x = 0; x < n; x++) {
3628                                                 Parameter op = (Parameter) ps.FixedParameters[x + arg_count];
3629                                                 Argument b = new Argument (op.ParameterInitializer, Argument.AType.Expression);
3630                                                 b.Resolve(ec, Location.Null);
3631                                                 newarglist.Add (b);
3632                                         }
3633                                 }
3634                         }
3635 #endif
3636                         return result;
3637                 }
3638
3639                 static bool compare_name_filter (MemberInfo m, object filterCriteria)
3640                 {
3641                         return (m.Name == ((string) filterCriteria));
3642                 }
3643
3644                 // We need an overload for OverloadResolve because Invocation.DoResolve
3645                 // must pass Arguments by reference, since a later call to IsApplicable
3646                 // can change the argument list if optional parameters are defined
3647                 // in the method declaration
3648                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
3649                                                           ArrayList Arguments, Location loc)
3650                 {
3651                         ArrayList a = Arguments;
3652                         return OverloadResolve (ec, me, ref a, loc);
3653                 }
3654
3655                 static string ToString(MethodBase mbase)
3656                 {
3657                         if (mbase == null)
3658                                 return "NULL";
3659
3660                         if (mbase is MethodBuilder)
3661                         {
3662                                 MethodBuilder mb = (MethodBuilder) mbase;
3663                                 String res = mb.ReturnType + " (";
3664                                 ParameterInfo [] parms = mb.GetParameters();
3665                                 for (int i = 0; i < parms.Length; i++) {
3666                                         if (i != 0)
3667                                                 res += " ";
3668                                         res += parms[i].ParameterType;
3669                                 }
3670                                 res += ")";
3671                                 return res;
3672                         }
3673
3674                         return mbase.ToString();
3675                 }
3676
3677                 /// <summary>
3678                 ///   Find the Applicable Function Members (7.4.2.1)
3679                 ///
3680                 ///   me: Method Group expression with the members to select.
3681                 ///       it might contain constructors or methods (or anything
3682                 ///       that maps to a method).
3683                 ///
3684                 ///   Arguments: ArrayList containing resolved Argument objects.
3685                 ///
3686                 ///   loc: The location if we want an error to be reported, or a Null
3687                 ///        location for "probing" purposes.
3688                 ///
3689                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3690                 ///            that is the best match of me on Arguments.
3691                 ///
3692                 /// </summary>
3693                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
3694                                                           ref ArrayList Arguments, Location loc)
3695                 {
3696                         ArrayList afm = new ArrayList ();
3697                         MethodBase method = null;
3698                         Type current_type = null;
3699                         int argument_count;
3700                         ArrayList candidates = new ArrayList ();
3701                         Hashtable expanded_candidates = new Hashtable();
3702                         int narrow_count = 0;
3703                         bool narrowing_candidate = false;
3704
3705                         foreach (MethodBase candidate in me.Methods){
3706                                 bool candidate_expanded;
3707                                 ConversionType m = IsApplicable (ec, Arguments, candidate, out candidate_expanded);
3708                                 if (candidate_expanded)
3709                                         expanded_candidates [candidate] = candidate;
3710                                 if (m == ConversionType.None)
3711                                         continue;
3712                                 else if (m == ConversionType.Narrowing) {
3713                                         if (method == null) {
3714                                                 method = candidate;
3715                                                 narrowing_candidate = true;
3716                                         }
3717                                         narrow_count++;
3718                                 } else if (m == ConversionType.Widening) {
3719                                         if (method == null || narrowing_candidate) {
3720                                                 method = candidate;
3721                                                 narrowing_candidate = false;
3722                                         } else {
3723                                                 Applicability res = BetterFunction (ec, Arguments, candidate, method, true, loc);
3724                                                 if (res == Applicability.Same)
3725                                                         continue; // should check it overrides?
3726                                                 if (res == Applicability.Better)
3727                                                         method = candidate;
3728                                         }
3729                                         candidates.Add (candidate);
3730                                 }
3731                         }
3732
3733                         if (candidates.Count == 0) {
3734                                 if (narrow_count > 1)
3735                                         method = null;
3736                                 else if (narrow_count == 1)
3737                                         candidates = null;
3738                         } else if (candidates.Count == 1) {
3739                                 method = (MethodBase)candidates [0];
3740                                 candidates = null;
3741                         } else
3742                                 narrow_count = 0;
3743
3744                         if (Arguments == null)
3745                                 argument_count = 0;
3746                         else
3747                                 argument_count = Arguments.Count;
3748
3749
3750                         if (method == null) {
3751                                 //
3752                                 // Okay so we have failed to find anything so we
3753                                 // return by providing info about the closest match
3754                                 //
3755                                 for (int i = 0; i < me.Methods.Length; ++i) {
3756
3757                                         MethodBase c = (MethodBase) me.Methods [i];
3758                                         ParameterData pd = GetParameterData (c);
3759
3760                                         if (pd.Count != argument_count)
3761                                                 continue;
3762
3763                                         bool dummy;
3764                                         if (narrow_count != 0) {
3765                                                 if (IsApplicable (ec, Arguments, c, out dummy) == ConversionType.None)
3766                                                         continue;
3767                                                 Report.Error (1502, loc,
3768                                                         "Overloaded match for method '" +
3769                                                         FullMethodDesc (c) +
3770                                                         "' requires narrowing conversionss");
3771                                         }
3772
3773                                         VerifyArgumentsCompat (ec, Arguments, argument_count, c, false,
3774                                                                null, loc);
3775                                 }
3776
3777                                 return null;
3778                         }
3779
3780                         //
3781                         // Now check that there are no ambiguities i.e the selected method
3782                         // should be better than all the others
3783                         //
3784
3785                         if (candidates != null) {
3786                                 foreach (MethodBase candidate in candidates){
3787                                         if (candidate == method)
3788                                                 continue;
3789
3790                                         if (BetterFunction (ec, Arguments, candidate, method,
3791                                                                 false, loc) == Applicability.Better) {
3792                                                 Report.Error (
3793                                                         121, loc,
3794                                                         "Ambiguous call of '" + me.Name + "' when selecting function due to implicit casts");
3795                                                 return null;
3796                                         }
3797                                 }
3798                         }
3799
3800                         //
3801                         // And now check if the arguments are all compatible, perform conversions
3802                         // if necessary etc. and return if everything is all right
3803                         //
3804                         if (method == null)
3805                                 return null;
3806
3807                         bool chose_params_expanded = expanded_candidates.Contains (method);
3808
3809                         Arguments = ConstructArgumentList(ec, Arguments, method);
3810                         if (VerifyArgumentsCompat (ec, Arguments, argument_count, method,
3811                                                    chose_params_expanded, null, loc))
3812                         {
3813                                 return method;
3814                         }
3815                         else
3816                                 return null;
3817                 }
3818
3819                 public static ArrayList ConstructArgumentList (EmitContext ec, ArrayList Arguments,     MethodBase method)
3820                 {
3821                         ArrayList newarglist = new ArrayList();
3822                         int arg_count = Arguments == null ? 0 : Arguments.Count;
3823
3824                         ParameterData pd = GetParameterData (method);
3825
3826
3827                         for (int i = 0; i < arg_count; i++) {
3828                                 Argument a = (Argument) Arguments [i];
3829                                 Type param_type = pd.ParameterType (i);
3830
3831                                 bool IsDelegate = TypeManager.IsDelegateType (param_type);
3832                                 if (IsDelegate) {
3833                                         if (a.ArgType == Argument.AType.AddressOf) {
3834                                                 a = new Argument ((Expression) a.Expr, Argument.AType.Expression);
3835                                                 ArrayList args = new ArrayList();
3836                                                 args.Add (a);
3837                                                 string param_name = pd.ParameterDesc(i).Replace('+', '.');
3838                                                 Expression pname = MonoBASIC.Parser.DecomposeQI (param_name, Location.Null);
3839
3840                                                 New temp_new = new New ((Expression)pname, args, Location.Null);
3841                                                 Expression del_temp = temp_new.DoResolve(ec);
3842                                                 a = new Argument (del_temp, Argument.AType.Expression);
3843                                                 a.Resolve(ec, Location.Null);
3844                                         }
3845                                 }
3846                                 if ((pd.ParameterModifier (i) & Parameter.Modifier.REF) != 0) {
3847                                         a.ArgType = Argument.AType.Ref;
3848                                         a.Resolve(ec, Location.Null);
3849                                 }
3850
3851                                 newarglist.Add (a);
3852                         }
3853
3854                         if (HasArrayParameter (pd) && arg_count == pd.Count - 1)
3855                                 return newarglist;
3856
3857                         for (int i = arg_count; i < pd.Count; i++) {
3858                                 Expression e = pd.DefaultValue (i);
3859                                 Argument a = new Argument (e, Argument.AType.Expression);
3860                                 if ((pd.ParameterModifier (i) & Parameter.Modifier.REF) != 0)
3861                                         a.ArgType = Argument.AType.Ref;
3862                                 e.Resolve (ec);
3863                                 a.Resolve (ec, Location.Null);
3864                                 newarglist.Add (a);
3865                         }
3866
3867                         return newarglist;
3868                 }
3869
3870                 public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
3871                         int argument_count,
3872                         MethodBase method,
3873                         bool chose_params_expanded,
3874                         Type delegate_type,
3875                         Location loc)
3876                 {
3877                         return (VerifyArgumentsCompat (ec, Arguments, argument_count,
3878                                 method, chose_params_expanded, delegate_type, loc, null));
3879                 }
3880
3881                 public static bool VerifyArgumentsCompat (EmitContext ec,
3882                                                           ArrayList Arguments,
3883                                                           int argument_count,
3884                                                           MethodBase method,
3885                                                           bool chose_params_expanded,
3886                                                           Type delegate_type,
3887                                                           Location loc,
3888                                                           string InvokingProperty)
3889                 {
3890                         ParameterData pd = GetParameterData (method);
3891                         int pd_count = pd.Count;
3892
3893                         for (int j = 0; j < argument_count; j++) {
3894                                 Argument a = (Argument) Arguments [j];
3895                                 Expression a_expr = a.Expr;
3896                                 Type parameter_type = pd.ParameterType(j);
3897
3898                                 if (parameter_type == null)
3899                                 {
3900                                         Error_WrongNumArguments(loc, (InvokingProperty == null)?((delegate_type == null)?FullMethodDesc (method):delegate_type.ToString ()):InvokingProperty, argument_count);
3901                                         return false;
3902                                 }
3903                                 if (pd.ParameterModifier (j) == Parameter.Modifier.PARAMS &&
3904                                 chose_params_expanded)
3905                                         parameter_type = TypeManager.TypeToCoreType (parameter_type.GetElementType ());
3906                                 if (a.Type != parameter_type){
3907                                         Expression conv;
3908
3909                                         conv = ConvertImplicit (ec, a_expr, parameter_type, loc);
3910
3911                                         if (conv == null) {
3912                                                 if (!Location.IsNull (loc)) {
3913                                                         if (delegate_type == null)
3914                                                                 if (InvokingProperty == null)
3915                                                                         Report.Error (1502, loc,
3916                                                                                 "The best overloaded match for method '" +
3917                                                                                 FullMethodDesc (method) +
3918                                                                                 "' has some invalid arguments");
3919                                                                 else
3920                                                                         Report.Error (1502, loc,
3921                                                                                 "Property '" +
3922                                                                                 InvokingProperty +
3923                                                                                 "' has some invalid arguments");
3924                                                         else
3925                                                                 Report.Error (1594, loc,
3926                                                                               "Delegate '" + delegate_type.ToString () +
3927                                                                               "' has some invalid arguments.");
3928                                                         Report.Error (1503, loc,
3929                                                          "Argument " + (j+1) +
3930                                                          ": Cannot convert from '" + Argument.FullDesc (a)
3931                                                          + "' to '" + pd.ParameterDesc (j) + "'");
3932                                                 }
3933
3934                                                 return false;
3935                                         }
3936
3937                                         //
3938                                         // Update the argument with the implicit conversion
3939                                         //
3940                                         if (a_expr != conv)
3941                                                 a.Expr = conv;
3942                                 }
3943
3944                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3945                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3946                                 Parameter.Modifier p_mod = pd.ParameterModifier (j) &
3947                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF | Parameter.Modifier.OPTIONAL);
3948
3949                                 if (a_mod != p_mod &&
3950                                     pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
3951                                         if (!Location.IsNull (loc)) {
3952                                                 Report.Error (1502, loc,
3953                                                        "The best overloaded match for method '" + FullMethodDesc (method)+
3954                                                        "' has some invalid arguments");
3955                                                 Report.Error (1503, loc,
3956                                                        "Argument " + (j+1) +
3957                                                        ": Cannot convert from '" + Argument.FullDesc (a)
3958                                                        + "' to '" + pd.ParameterDesc (j) + "'");
3959                                         }
3960
3961                                         return false;
3962                                 }
3963                         }
3964
3965                         return true;
3966                 }
3967
3968                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
3969                 {
3970                         this.is_left_hand = true;
3971                         Expression expr_to_return = DoResolve (ec);
3972
3973                         if (expr_to_return is IndexerAccess) {
3974                                 IndexerAccess ia = expr_to_return as IndexerAccess;
3975                                 expr_to_return = ia.DoResolveLValue (ec, right_side);
3976                         }
3977
3978                         return expr_to_return;
3979                 }
3980
3981                 public override Expression DoResolve (EmitContext ec)
3982                 {
3983                         //
3984                         // First, resolve the expression that is used to
3985                         // trigger the invocation
3986                         //
3987                         Expression expr_to_return = null;
3988
3989                         if (expr is BaseAccess)
3990                                 is_base = true;
3991
3992                         if ((ec.ReturnType != null) && (expr.ToString() == ec.BlockName)) {
3993                                 ec.InvokingOwnOverload = true;
3994                                 expr = expr.Resolve (ec, ResolveFlags.MethodGroup);
3995                                 ec.InvokingOwnOverload = false;
3996                         }
3997                         else
3998                         {
3999                                 ec.InvokingOwnOverload = false;
4000                                 expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
4001                         }
4002                         if (expr == null)
4003                                 return null;
4004
4005                         if (expr is Invocation) {
4006                                 // FIXME Calls which return an Array are not resolved (here or in the grammar)
4007                                 expr = expr.Resolve(ec);
4008                         }
4009
4010                         if (!(expr is MethodGroupExpr))
4011                         {
4012                                 Type expr_type = expr.Type;
4013
4014                                 if (expr_type != null)
4015                                 {
4016                                         bool IsDelegate = TypeManager.IsDelegateType (expr_type);
4017                                         if (IsDelegate)
4018                                                 return (new DelegateInvocation (
4019                                                         this.expr, Arguments, loc)).Resolve (ec);
4020                                 }
4021                         }
4022
4023                         //
4024                         // Next, evaluate all the expressions in the argument list
4025                         //
4026                         if (Arguments != null)
4027                         {
4028                                 foreach (Argument a in Arguments)
4029                                 {
4030                                         if ((a.ArgType == Argument.AType.NoArg) && (!(expr is MethodGroupExpr)))
4031                                                 Report.Error (999, "This item cannot have empty arguments");
4032
4033                                         if (!a.Resolve (ec, loc))
4034                                                 return null;
4035                                 }
4036                         }
4037
4038                         if (expr is MethodGroupExpr)
4039                         {
4040                                 MethodGroupExpr mg = (MethodGroupExpr) expr;
4041                                 method = OverloadResolve (ec, mg, ref Arguments, loc);
4042
4043                                 if (method == null)
4044                                 {
4045                                         Error (30455,
4046                                                 "Could not find any applicable function to invoke for this argument list");
4047                                         return null;
4048                                 }
4049
4050                                 if ((method as MethodInfo) != null)
4051                                 {
4052                                         MethodInfo mi = method as MethodInfo;
4053                                         type = TypeManager.TypeToCoreType (mi.ReturnType);
4054                                         if (!mi.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null))
4055                                                 SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
4056                                 }
4057
4058                                 if ((method as ConstructorInfo) != null)
4059                                 {
4060                                         ConstructorInfo ci = method as ConstructorInfo;
4061                                         type = TypeManager.void_type;
4062                                         if (!ci.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null))
4063                                                 SimpleName.Error_ObjectRefRequired (ec, loc, ci.Name);
4064                                 }
4065
4066                                 if (type.IsPointer)
4067                                 {
4068                                         if (!ec.InUnsafe)
4069                                         {
4070                                                 UnsafeError (loc);
4071                                                 return null;
4072                                         }
4073                                 }
4074                                 eclass = ExprClass.Value;
4075                                 expr_to_return = this;
4076                         }
4077
4078                         if (expr is PropertyExpr)
4079                         {
4080                                 PropertyExpr pe = ((PropertyExpr) expr);
4081                                 pe.PropertyArgs = (ArrayList) Arguments.Clone();
4082                                 Arguments.Clear();
4083                                 Arguments = new ArrayList();
4084                                 MethodBase mi = pe.PropertyInfo.GetGetMethod(true);
4085
4086                                 if(VerifyArgumentsCompat (ec, pe.PropertyArgs,
4087                                         pe.PropertyArgs.Count, mi, false, null, loc, pe.Name))
4088                                 {
4089
4090                                         expr_to_return = pe.DoResolve (ec);
4091                                         expr_to_return.eclass = ExprClass.PropertyAccess;
4092                                 }
4093                                 else
4094                                 {
4095                                         throw new Exception("Error resolving Property Access expression\n" + pe.ToString());
4096                                 }
4097                         }
4098
4099                         if (expr is FieldExpr || expr is LocalVariableReference || expr is ParameterReference) {
4100                                 if (expr.Type.IsArray) {
4101                                         // If we are here, expr must be an ArrayAccess
4102                                         ArrayList idxs = new ArrayList();
4103                                         foreach (Argument a in Arguments)
4104                                         {
4105                                                 idxs.Add (a.Expr);
4106                                         }
4107                                         ElementAccess ea = new ElementAccess (expr, idxs, expr.Location);
4108                                         ArrayAccess aa = new ArrayAccess (ea, expr.Location);
4109                                         expr_to_return = aa.DoResolve(ec);
4110                                         expr_to_return.eclass = ExprClass.Variable;
4111                                 } else {
4112                                         //
4113                                         // check whether this is a indexer
4114                                         //
4115                                         ArrayList idxs = new ArrayList();
4116                                         foreach (Argument a in Arguments) {
4117                                                 idxs.Add (a.Expr);
4118                                         }
4119                                         ElementAccess ea = new ElementAccess (expr, idxs, expr.Location);
4120                                         IndexerAccess ia = new IndexerAccess (ea, expr.Location);
4121                                         if (!is_left_hand)
4122                         expr_to_return = ia.DoResolve(ec);
4123                                         else
4124                                                 expr_to_return = ia.DoResolve(ec);
4125                                         //
4126                                         // Since all the above are failed we need to do
4127                                         // late binding
4128                                         //
4129                                         if (expr_to_return == null) {
4130
4131                                                 // We can't resolve now, but we
4132                                                 // have to try to access the array with a call
4133                                                 // to LateIndexGet/Set in the runtime
4134                                                 Expression lig_call_expr;
4135
4136                                                 if (!is_left_hand)
4137                                                         lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexGet", Location.Null);
4138                                                 else
4139                                                         lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexSet", Location.Null);
4140                                                 Expression obj_type = Mono.MonoBASIC.Parser.DecomposeQI("System.Object", Location.Null);
4141                                                 ArrayList adims = new ArrayList();
4142
4143                                                 ArrayList ainit = new ArrayList();
4144                                                 foreach (Argument a in Arguments)
4145                                                         ainit.Add ((Expression) a.Expr);
4146
4147                                                 adims.Add ((Expression) new IntLiteral (Arguments.Count));
4148
4149                                                 Expression oace = new ArrayCreation (obj_type, adims, "", ainit, Location.Null);
4150
4151                                                 ArrayList args = new ArrayList();
4152                                                 args.Add (new Argument(expr, Argument.AType.Expression));
4153                                                 args.Add (new Argument(oace, Argument.AType.Expression));
4154                                                 args.Add (new Argument(NullLiteral.Null, Argument.AType.Expression));
4155
4156                                                 Expression lig_call = new Invocation (lig_call_expr, args, Location.Null);
4157                                                 expr_to_return = lig_call.Resolve(ec);
4158                                                 expr_to_return.eclass = ExprClass.Variable;
4159                                         }
4160                                 }
4161                         }
4162
4163                         return expr_to_return;
4164                 }
4165
4166         static void Error_WrongNumArguments (Location loc, String name, int arg_count)
4167         {
4168             Report.Error (1501, loc, "No overload for method `" + name + "' takes `" +
4169                                       arg_count + "' arguments");
4170         }
4171
4172                 // <summary>
4173                 //   Emits the list of arguments as an array
4174                 // </summary>
4175                 static void EmitParams (EmitContext ec, int idx, ArrayList arguments)
4176                 {
4177                         ILGenerator ig = ec.ig;
4178                         int count = arguments.Count - idx;
4179                         Argument a = (Argument) arguments [idx];
4180                         Type t = a.Expr.Type;
4181                         string array_type = t.FullName + "[]";
4182                         LocalBuilder array;
4183
4184                         array = ig.DeclareLocal (TypeManager.LookupType (array_type));
4185                         IntConstant.EmitInt (ig, count);
4186                         ig.Emit (OpCodes.Newarr, TypeManager.TypeToCoreType (t));
4187                         ig.Emit (OpCodes.Stloc, array);
4188
4189                         int top = arguments.Count;
4190                         for (int j = idx; j < top; j++){
4191                                 a = (Argument) arguments [j];
4192
4193                                 ig.Emit (OpCodes.Ldloc, array);
4194                                 IntConstant.EmitInt (ig, j - idx);
4195                                 a.Emit (ec);
4196
4197                                 ArrayAccess.EmitStoreOpcode (ig, t);
4198                         }
4199                         ig.Emit (OpCodes.Ldloc, array);
4200                 }
4201
4202                 /// <summary>
4203                 ///   Emits a list of resolved Arguments that are in the arguments
4204                 ///   ArrayList.
4205                 /// </summary>
4206                 public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments)
4207                 {
4208                         ParameterData pd = GetParameterData (mb);
4209
4210                         //
4211                         // If we are calling a params method with no arguments, special case it
4212                         //
4213                         if (arguments == null){
4214                                 if (pd.Count > 0 &&
4215                                     pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
4216                                         ILGenerator ig = ec.ig;
4217
4218                                         IntConstant.EmitInt (ig, 0);
4219                                         ig.Emit (OpCodes.Newarr, pd.ParameterType (0).GetElementType ());
4220                                 }
4221                                 return;
4222                         }
4223
4224                         int top = arguments.Count;
4225
4226                         for (int i = 0; i < top; i++){
4227                                 Argument a = (Argument) arguments [i];
4228
4229                                 if (pd.ParameterModifier (i) == Parameter.Modifier.PARAMS){
4230                                         //
4231                                         // Special case if we are passing the same data as the
4232                                         // params argument, do not put it in an array.
4233                                         //
4234                                         if (pd.ParameterType (i) == a.Type)
4235                                                 a.Emit (ec);
4236                                         else
4237                                                 EmitParams (ec, i, arguments);
4238                                         return;
4239                                 }
4240
4241                                 if ((a.ArgType == Argument.AType.Ref || a.ArgType == Argument.AType.Out) &&
4242                                         !(a.Expr is IMemoryLocation)) {
4243                                         LocalTemporary tmp = new LocalTemporary (ec, pd.ParameterType (i));
4244
4245                                         a.Expr.Emit (ec);
4246                                         tmp.Store (ec);
4247                                         a = new Argument (tmp, a.ArgType);
4248                                 }
4249
4250                                 a.Emit (ec);
4251                         }
4252
4253                         if (pd.Count > top &&
4254                             pd.ParameterModifier (top) == Parameter.Modifier.PARAMS){
4255                                 ILGenerator ig = ec.ig;
4256
4257                                 IntConstant.EmitInt (ig, 0);
4258                                 ig.Emit (OpCodes.Newarr, pd.ParameterType (top).GetElementType ());
4259                         }
4260                 }
4261
4262                 /// <remarks>
4263                 ///   is_base tells whether we want to force the use of the 'call'
4264                 ///   opcode instead of using callvirt.  Call is required to call
4265                 ///   a specific method, while callvirt will always use the most
4266                 ///   recent method in the vtable.
4267                 ///
4268                 ///   is_static tells whether this is an invocation on a static method
4269                 ///
4270                 ///   instance_expr is an expression that represents the instance
4271                 ///   it must be non-null if is_static is false.
4272                 ///
4273                 ///   method is the method to invoke.
4274                 ///
4275                 ///   Arguments is the list of arguments to pass to the method or constructor.
4276                 /// </remarks>
4277                 public static void EmitCall (EmitContext ec, bool is_base,
4278                                              bool is_static, Expression instance_expr,
4279                                              MethodBase method, ArrayList Arguments, Location loc)
4280                 {
4281                         EmitCall (ec, is_base, is_static, instance_expr, method, Arguments, null, loc);
4282                 }
4283
4284                 public static void EmitCall (EmitContext ec, bool is_base,
4285                         bool is_static, Expression instance_expr,
4286                         MethodBase method, ArrayList Arguments, ArrayList prop_args, Location loc)
4287                 {
4288                         ILGenerator ig = ec.ig;
4289                         bool struct_call = false;
4290
4291                         Type decl_type = method.DeclaringType;
4292
4293                         if (!RootContext.StdLib)
4294                         {
4295                                 // Replace any calls to the system's System.Array type with calls to
4296                                 // the newly created one.
4297                                 if (method == TypeManager.system_int_array_get_length)
4298                                         method = TypeManager.int_array_get_length;
4299                                 else if (method == TypeManager.system_int_array_get_rank)
4300                                         method = TypeManager.int_array_get_rank;
4301                                 else if (method == TypeManager.system_object_array_clone)
4302                                         method = TypeManager.object_array_clone;
4303                                 else if (method == TypeManager.system_int_array_get_length_int)
4304                                         method = TypeManager.int_array_get_length_int;
4305                                 else if (method == TypeManager.system_int_array_get_lower_bound_int)
4306                                         method = TypeManager.int_array_get_lower_bound_int;
4307                                 else if (method == TypeManager.system_int_array_get_upper_bound_int)
4308                                         method = TypeManager.int_array_get_upper_bound_int;
4309                                 else if (method == TypeManager.system_void_array_copyto_array_int)
4310                                         method = TypeManager.void_array_copyto_array_int;
4311                         }
4312
4313                         //
4314                         // This checks the 'ConditionalAttribute' on the method, and the
4315                         // ObsoleteAttribute
4316                         //
4317                         TypeManager.MethodFlags flags = TypeManager.GetMethodFlags (method, loc);
4318                         if ((flags & TypeManager.MethodFlags.IsObsoleteError) != 0)
4319                                 return;
4320                         if ((flags & TypeManager.MethodFlags.ShouldIgnore) != 0)
4321                                 return;
4322
4323                         if (!is_static)
4324                         {
4325                                 if (decl_type.IsValueType)
4326                                         struct_call = true;
4327                                 //
4328                                 // If this is ourselves, push "this"
4329                                 //
4330                                 if (instance_expr == null)
4331                                 {
4332                                         ig.Emit (OpCodes.Ldarg_0);
4333                                 }
4334                                 else
4335                                 {
4336                                         //
4337                                         // Push the instance expression
4338                                         //
4339                                         if (instance_expr.Type.IsValueType)
4340                                         {
4341                                                 //
4342                                                 // Special case: calls to a function declared in a
4343                                                 // reference-type with a value-type argument need
4344                                                 // to have their value boxed.
4345
4346                                                 struct_call = true;
4347                                                 if (decl_type.IsValueType)
4348                                                 {
4349                                                         //
4350                                                         // If the expression implements IMemoryLocation, then
4351                                                         // we can optimize and use AddressOf on the
4352                                                         // return.
4353                                                         //
4354                                                         // If not we have to use some temporary storage for
4355                                                         // it.
4356                                                         if (instance_expr is IMemoryLocation)
4357                                                         {
4358                                                                 ((IMemoryLocation)instance_expr).
4359                                                                         AddressOf (ec, AddressOp.LoadStore);
4360                                                         }
4361                                                         else
4362                                                         {
4363                                                                 Type t = instance_expr.Type;
4364
4365                                                                 instance_expr.Emit (ec);
4366                                                                 LocalBuilder temp = ig.DeclareLocal (t);
4367                                                                 ig.Emit (OpCodes.Stloc, temp);
4368                                                                 ig.Emit (OpCodes.Ldloca, temp);
4369                                                         }
4370                                                 }
4371                                                 else
4372                                                 {
4373                                                         instance_expr.Emit (ec);
4374                                                         ig.Emit (OpCodes.Box, instance_expr.Type);
4375                                                 }
4376                                         }
4377                                         else
4378                                                 instance_expr.Emit (ec);
4379                                 }
4380                         }
4381
4382                         if (prop_args != null && prop_args.Count > 0)
4383                         {
4384                                 if (Arguments == null)
4385                                         Arguments = new ArrayList();
4386
4387                                 for (int i = prop_args.Count-1; i >=0 ; i--)
4388                                 {
4389                                         Arguments.Insert (0,prop_args[i]);
4390                                 }
4391
4392                         }
4393
4394                         EmitArguments (ec, method, Arguments);
4395
4396                         if (is_static || struct_call || is_base)
4397                         {
4398                                 if (method is MethodInfo)
4399                                 {
4400                                         ig.Emit (OpCodes.Call, (MethodInfo) method);
4401                                 }
4402                                 else
4403                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4404                         }
4405                         else
4406                         {
4407                                 if (method is MethodInfo)
4408                                         ig.Emit (OpCodes.Callvirt, (MethodInfo) method);
4409                                 else
4410                                         ig.Emit (OpCodes.Callvirt, (ConstructorInfo) method);
4411                         }
4412                 }
4413
4414                 static void EmitPropertyArgs (EmitContext ec, ArrayList prop_args)
4415                 {
4416                         int top = prop_args.Count;
4417
4418                         for (int i = 0; i < top; i++)
4419                         {
4420                                 Argument a = (Argument) prop_args [i];
4421                                 a.Emit (ec);
4422                         }
4423                 }
4424
4425                 public override void Emit (EmitContext ec)
4426                 {
4427                         MethodGroupExpr mg = (MethodGroupExpr) this.expr;
4428
4429                         EmitCall (
4430                                 ec, is_base, method.IsStatic, mg.InstanceExpression, method, Arguments, loc);
4431                 }
4432
4433                 public override void EmitStatement (EmitContext ec)
4434                 {
4435                         Emit (ec);
4436
4437                         //
4438                         // Pop the return value if there is one
4439                         //
4440                         if (method is MethodInfo){
4441                                 Type ret = ((MethodInfo)method).ReturnType;
4442                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
4443                                         ec.ig.Emit (OpCodes.Pop);
4444                         }
4445                 }
4446         }
4447
4448         //
4449         // This class is used to "disable" the code generation for the
4450         // temporary variable when initializing value types.
4451         //
4452         class EmptyAddressOf : EmptyExpression, IMemoryLocation {
4453                 public void AddressOf (EmitContext ec, AddressOp Mode)
4454                 {
4455                         // nothing
4456                 }
4457         }
4458
4459         /// <summary>
4460         ///    Implements the new expression
4461         /// </summary>
4462         public class New : ExpressionStatement {
4463                 public readonly ArrayList Arguments;
4464                 public readonly Expression RequestedType;
4465
4466                 MethodBase method = null;
4467
4468                 //
4469                 // If set, the new expression is for a value_target, and
4470                 // we will not leave anything on the stack.
4471                 //
4472                 Expression value_target;
4473                 bool value_target_set = false;
4474                 public bool isDelegate = false;
4475
4476                 public New (Expression requested_type, ArrayList arguments, Location l)
4477                 {
4478                         RequestedType = requested_type;
4479                         Arguments = arguments;
4480                         loc = l;
4481                 }
4482
4483                 public Expression ValueTypeVariable {
4484                         get {
4485                                 return value_target;
4486                         }
4487
4488                         set {
4489                                 value_target = value;
4490                                 value_target_set = true;
4491                         }
4492                 }
4493
4494                 //
4495                 // This function is used to disable the following code sequence for
4496                 // value type initialization:
4497                 //
4498                 // AddressOf (temporary)
4499                 // Construct/Init
4500                 // LoadTemporary
4501                 //
4502                 // Instead the provide will have provided us with the address on the
4503                 // stack to store the results.
4504                 //
4505                 static Expression MyEmptyExpression;
4506
4507                 public void DisableTemporaryValueType ()
4508                 {
4509                         if (MyEmptyExpression == null)
4510                                 MyEmptyExpression = new EmptyAddressOf ();
4511
4512                         //
4513                         // To enable this, look into:
4514                         // test-34 and test-89 and self bootstrapping.
4515                         //
4516                         // For instance, we can avoid a copy by using 'newobj'
4517                         // instead of Call + Push-temp on value types.
4518 //                      value_target = MyEmptyExpression;
4519                 }
4520
4521                 public override Expression DoResolve (EmitContext ec)
4522                 {
4523                         if (this.isDelegate) {
4524                                 // if its a delegate resolve the type of RequestedType first
4525                                 Expression dtype = RequestedType.Resolve(ec);
4526                                 string ts = (dtype.Type.ToString()).Replace ('+','.');
4527                                 dtype = Mono.MonoBASIC.Parser.DecomposeQI (ts, Location.Null);
4528
4529                                 type = ec.DeclSpace.ResolveType (dtype, false, loc);
4530                         }
4531                         else
4532                                 type = ec.DeclSpace.ResolveType (RequestedType, false, loc);
4533
4534                         if (type == null)
4535                                 return null;
4536
4537                         bool IsDelegate = TypeManager.IsDelegateType (type);
4538
4539                         if (IsDelegate)
4540                                 return (new NewDelegate (type, Arguments, loc)).Resolve (ec);
4541
4542                         if (type.IsInterface || type.IsAbstract){
4543                                 Error (
4544                                         30376, "It is not possible to create instances of Interfaces " +
4545                                         "or classes marked as MustInherit");
4546                                 return null;
4547                         }
4548
4549                         bool is_struct = false;
4550                         is_struct = type.IsValueType;
4551                         eclass = ExprClass.Value;
4552
4553                         //
4554                         // SRE returns a match for .ctor () on structs (the object constructor),
4555                         // so we have to manually ignore it.
4556                         //
4557                         if (is_struct && Arguments == null)
4558                                 return this;
4559
4560                         Expression ml;
4561                         ml = MemberLookupFinal (ec, type, ".ctor",
4562                                                 MemberTypes.Constructor,
4563                                                 AllBindingFlags | BindingFlags.Public, loc);
4564
4565                         if (ml == null)
4566                                 return null;
4567
4568                         if (! (ml is MethodGroupExpr)){
4569                                 if (!is_struct){
4570                                         ml.Error118 ("method group");
4571                                         return null;
4572                                 }
4573                         }
4574
4575                         if (ml != null) {
4576                                 if (Arguments != null){
4577                                         foreach (Argument a in Arguments){
4578                                                 if (!a.Resolve (ec, loc))
4579                                                         return null;
4580                                         }
4581                                 }
4582
4583                                 method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml,
4584                                                                      Arguments, loc);
4585
4586                         }
4587
4588                         if (method == null) {
4589                                 if (!is_struct || Arguments.Count > 0) {
4590                                         Error (1501,
4591                                                "New invocation: Can not find a constructor for " +
4592                                                "this argument list");
4593                                         return null;
4594                                 }
4595                         }
4596                         return this;
4597                 }
4598
4599                 //
4600                 // This DoEmit can be invoked in two contexts:
4601                 //    * As a mechanism that will leave a value on the stack (new object)
4602                 //    * As one that wont (init struct)
4603                 //
4604                 // You can control whether a value is required on the stack by passing
4605                 // need_value_on_stack.  The code *might* leave a value on the stack
4606                 // so it must be popped manually
4607                 //
4608                 // If we are dealing with a ValueType, we have a few
4609                 // situations to deal with:
4610                 //
4611                 //    * The target is a ValueType, and we have been provided
4612                 //      the instance (this is easy, we are being assigned).
4613                 //
4614                 //    * The target of New is being passed as an argument,
4615                 //      to a boxing operation or a function that takes a
4616                 //      ValueType.
4617                 //
4618                 //      In this case, we need to create a temporary variable
4619                 //      that is the argument of New.
4620                 //
4621                 // Returns whether a value is left on the stack
4622                 //
4623                 bool DoEmit (EmitContext ec, bool need_value_on_stack)
4624                 {
4625                         bool is_value_type = type.IsValueType;
4626                         ILGenerator ig = ec.ig;
4627
4628                         if (is_value_type){
4629                                 IMemoryLocation ml;
4630
4631                                 // Allow DoEmit() to be called multiple times.
4632                                 // We need to create a new LocalTemporary each time since
4633                                 // you can't share LocalBuilders among ILGeneators.
4634                                 if (!value_target_set)
4635                                         value_target = new LocalTemporary (ec, type);
4636
4637                                 ml = (IMemoryLocation) value_target;
4638                                 ml.AddressOf (ec, AddressOp.Store);
4639                         }
4640
4641                         if (method != null)
4642                                 Invocation.EmitArguments (ec, method, Arguments);
4643
4644                         if (is_value_type){
4645                                 if (method == null)
4646                                         ig.Emit (OpCodes.Initobj, type);
4647                                 else
4648                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4649                                 if (need_value_on_stack){
4650                                         value_target.Emit (ec);
4651                                         return true;
4652                                 }
4653                                 return false;
4654                         } else {
4655                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) method);
4656                                 return true;
4657                         }
4658                 }
4659
4660                 public override void Emit (EmitContext ec)
4661                 {
4662                         DoEmit (ec, true);
4663                 }
4664
4665                 public override void EmitStatement (EmitContext ec)
4666                 {
4667                         if (DoEmit (ec, false))
4668                                 ec.ig.Emit (OpCodes.Pop);
4669                 }
4670         }
4671
4672         /// <summary>
4673         ///   14.5.10.2: Represents an array creation expression.
4674         /// </summary>
4675         ///
4676         /// <remarks>
4677         ///   There are two possible scenarios here: one is an array creation
4678         ///   expression that specifies the dimensions and optionally the
4679         ///   initialization data and the other which does not need dimensions
4680         ///   specified but where initialization data is mandatory.
4681         /// </remarks>
4682         public class ArrayCreation : ExpressionStatement {
4683                 Expression requested_base_type;
4684                 ArrayList initializers;
4685
4686                 //
4687                 // The list of Argument types.
4688                 // This is used to construct the 'newarray' or constructor signature
4689                 //
4690                 ArrayList arguments;
4691
4692                 //
4693                 // Method used to create the array object.
4694                 //
4695                 MethodBase new_method = null;
4696
4697                 Type array_element_type;
4698                 Type underlying_type;
4699                 bool is_one_dimensional = false;
4700                 bool is_builtin_type = false;
4701                 bool expect_initializers = false;
4702                 int num_arguments = 0;
4703                 int dimensions = 0;
4704                 string rank;
4705
4706                 ArrayList array_data;
4707
4708                 Hashtable bounds;
4709
4710                 //
4711                 // The number of array initializers that we can handle
4712                 // via the InitializeArray method - through EmitStaticInitializers
4713                 //
4714                 int num_automatic_initializers;
4715
4716                 public ArrayCreation (Expression requested_base_type, ArrayList exprs, string rank, ArrayList initializers, Location l)
4717                 {
4718                         this.requested_base_type = requested_base_type;
4719                         this.initializers = initializers;
4720                         this.rank = rank;
4721                         loc = l;
4722
4723                         arguments = new ArrayList ();
4724
4725                         foreach (Expression e in exprs) {
4726                                 arguments.Add (new Argument (e, Argument.AType.Expression));
4727                                 num_arguments++;
4728                         }
4729                 }
4730
4731                 public ArrayCreation (Expression requested_base_type, string rank, ArrayList initializers, Location l)
4732                 {
4733                         this.requested_base_type = requested_base_type;
4734                         this.initializers = initializers;
4735                         this.rank = rank;
4736                         loc = l;
4737
4738                         //this.rank = rank.Substring (0, rank.LastIndexOf ("["));
4739                         //
4740                         //string tmp = rank.Substring (rank.LastIndexOf ("["));
4741                         //
4742                         //dimensions = tmp.Length - 1;
4743                         expect_initializers = true;
4744                 }
4745
4746                 public Expression FormArrayType (Expression base_type, int idx_count, string rank)
4747                 {
4748                         StringBuilder sb = new StringBuilder (rank);
4749
4750                         sb.Append ("[");
4751                         for (int i = 1; i < idx_count; i++)
4752                                 sb.Append (",");
4753
4754                         sb.Append ("]");
4755
4756                         return new ComposedCast (base_type, sb.ToString (), loc);
4757                 }
4758
4759                 void Error_IncorrectArrayInitializer ()
4760                 {
4761                         Error (30567, "Incorrectly structured array initializer");
4762                 }
4763
4764                 public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
4765                 {
4766                         if (specified_dims) {
4767                                 Argument a = (Argument) arguments [idx];
4768
4769                                 if (!a.Resolve (ec, loc))
4770                                         return false;
4771
4772                                 if (!(a.Expr is Constant)) {
4773                                         Error (150, "A constant value is expected");
4774                                         return false;
4775                                 }
4776
4777                                 int value = (int) ((Constant) a.Expr).GetValue ();
4778
4779                                 if (value != probe.Count) {
4780                                         Error_IncorrectArrayInitializer ();
4781                                         return false;
4782                                 }
4783
4784                                 bounds [idx] = value;
4785                         }
4786
4787                         int child_bounds = -1;
4788                         foreach (object o in probe) {
4789                                 if (o is ArrayList) {
4790                                         int current_bounds = ((ArrayList) o).Count;
4791
4792                                         if (child_bounds == -1)
4793                                                 child_bounds = current_bounds;
4794
4795                                         else if (child_bounds != current_bounds){
4796                                                 Error_IncorrectArrayInitializer ();
4797                                                 return false;
4798                                         }
4799                                         bool ret = CheckIndices (ec, (ArrayList) o, idx + 1, specified_dims);
4800                                         if (!ret)
4801                                                 return false;
4802                                 } else {
4803                                         if (child_bounds != -1){
4804                                                 Error_IncorrectArrayInitializer ();
4805                                                 return false;
4806                                         }
4807
4808                                         Expression tmp = (Expression) o;
4809                                         tmp = tmp.Resolve (ec);
4810                                         if (tmp == null)
4811                                                 continue;
4812
4813                                         // Console.WriteLine ("I got: " + tmp);
4814                                         // Handle initialization from vars, fields etc.
4815
4816                                         Expression conv = ConvertImplicitRequired (
4817                                                 ec, tmp, underlying_type, loc);
4818
4819                                         if (conv == null)
4820                                                 return false;
4821
4822                                         if (conv is StringConstant)
4823                                                 array_data.Add (conv);
4824                                         else if (conv is Constant) {
4825                                                 array_data.Add (conv);
4826                                                 num_automatic_initializers++;
4827                                         } else
4828                                                 array_data.Add (conv);
4829                                 }
4830                         }
4831
4832                         return true;
4833                 }
4834
4835                 public void UpdateIndices (EmitContext ec)
4836                 {
4837                         int i = 0;
4838                         for (ArrayList probe = initializers; probe != null;) {
4839                                 if (probe.Count > 0 && probe [0] is ArrayList) {
4840                                         Expression e = new IntConstant (probe.Count);
4841                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4842
4843                                         bounds [i++] =  probe.Count;
4844
4845                                         probe = (ArrayList) probe [0];
4846
4847                                 } else {
4848                                         Expression e = new IntConstant (probe.Count);
4849                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4850
4851                                         bounds [i++] = probe.Count;
4852                                         probe = null;
4853                                 }
4854                         }
4855
4856                 }
4857
4858                 public bool ValidateInitializers (EmitContext ec, Type array_type)
4859                 {
4860                         if (initializers == null) {
4861                                 if (expect_initializers)
4862                                         return false;
4863                                 else
4864                                         return true;
4865                         }
4866
4867                         if (underlying_type == null)
4868                                 return false;
4869
4870                         //
4871                         // We use this to store all the date values in the order in which we
4872                         // will need to store them in the byte blob later
4873                         //
4874                         array_data = new ArrayList ();
4875                         bounds = new Hashtable ();
4876
4877                         bool ret;
4878
4879                         if (arguments != null) {
4880                                 ret = CheckIndices (ec, initializers, 0, true);
4881                                 return ret;
4882                         } else {
4883                                 arguments = new ArrayList ();
4884
4885                                 ret = CheckIndices (ec, initializers, 0, false);
4886
4887                                 if (!ret)
4888                                         return false;
4889
4890                                 UpdateIndices (ec);
4891
4892                                 if (arguments.Count != dimensions) {
4893                                         Error_IncorrectArrayInitializer ();
4894                                         return false;
4895                                 }
4896
4897                                 return ret;
4898                         }
4899                 }
4900
4901                 void Error_NegativeArrayIndex ()
4902                 {
4903                         Error (284, "Can not create array with a negative size");
4904                 }
4905
4906                 //
4907                 // Converts 'source' to an int, uint, long or ulong.
4908                 //
4909                 Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
4910                 {
4911                         Expression target;
4912
4913                         bool old_checked = ec.CheckState;
4914                         ec.CheckState = true;
4915
4916                         target = ConvertImplicit (ec, source, TypeManager.int32_type, loc);
4917                         if (target == null){
4918                                 target = ConvertImplicit (ec, source, TypeManager.uint32_type, loc);
4919                                 if (target == null){
4920                                         target = ConvertImplicit (ec, source, TypeManager.int64_type, loc);
4921                                         if (target == null){
4922                                                 target = ConvertImplicit (ec, source, TypeManager.uint64_type, loc);
4923                                                 if (target == null)
4924                                                         Expression.Error_CannotConvertImplicit (loc, source.Type, TypeManager.int32_type);
4925                                         }
4926                                 }
4927                         }
4928                         ec.CheckState = old_checked;
4929
4930                         //
4931                         // Only positive constants are allowed at compile time
4932                         //
4933                         if (target is Constant){
4934                                 if (target is IntConstant){
4935                                         if (((IntConstant) target).Value < 0){
4936                                                 Error_NegativeArrayIndex ();
4937                                                 return null;
4938                                         }
4939                                 }
4940
4941                                 if (target is LongConstant){
4942                                         if (((LongConstant) target).Value < 0){
4943                                                 Error_NegativeArrayIndex ();
4944                                                 return null;
4945                                         }
4946                                 }
4947
4948                         }
4949
4950                         return target;
4951                 }
4952
4953                 //
4954                 // Creates the type of the array
4955                 //
4956                 bool LookupType (EmitContext ec)
4957                 {
4958                         StringBuilder array_qualifier = new StringBuilder (rank);
4959
4960                         //
4961                         // 'In the first form allocates an array instace of the type that results
4962                         // from deleting each of the individual expression from the expression list'
4963                         //
4964                         if (num_arguments > 0) {
4965                                 array_qualifier.Append ("[");
4966                                 for (int i = num_arguments-1; i > 0; i--)
4967                                         array_qualifier.Append (",");
4968                                 array_qualifier.Append ("]");
4969                         }
4970
4971                         //
4972                         // Lookup the type
4973                         //
4974                         Expression array_type_expr;
4975                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
4976                         string sss = array_qualifier.ToString ();
4977                         type = ec.DeclSpace.ResolveType (array_type_expr, false, loc);
4978
4979                         if (type == null)
4980                                 return false;
4981
4982                         underlying_type = type;
4983                         if (underlying_type.IsArray)
4984                                 underlying_type = TypeManager.TypeToCoreType (underlying_type.GetElementType ());
4985                         dimensions = type.GetArrayRank ();
4986
4987                         return true;
4988                 }
4989
4990                 public override Expression DoResolve (EmitContext ec)
4991                 {
4992                         int arg_count;
4993
4994                         if (!LookupType (ec))
4995                                 return null;
4996
4997                         //
4998                         // First step is to validate the initializers and fill
4999                         // in any missing bits
5000                         //
5001                         if (!ValidateInitializers (ec, type))
5002                                 return null;
5003
5004                         if (arguments == null)
5005                                 arg_count = 0;
5006                         else {
5007                                 arg_count = arguments.Count;
5008                                 foreach (Argument a in arguments){
5009                                         if (!a.Resolve (ec, loc))
5010                                                 return null;
5011
5012                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
5013                                         if (real_arg == null)
5014                                                 return null;
5015
5016                                         a.Expr = real_arg;
5017                                 }
5018                         }
5019
5020                         array_element_type = TypeManager.TypeToCoreType (type.GetElementType ());
5021
5022                         if (arg_count == 1) {
5023                                 is_one_dimensional = true;
5024                                 eclass = ExprClass.Value;
5025                                 return this;
5026                         }
5027
5028                         is_builtin_type = TypeManager.IsBuiltinType (type);
5029
5030                         if (is_builtin_type) {
5031                                 Expression ml;
5032
5033                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
5034                                                    AllBindingFlags, loc);
5035
5036                                 if (!(ml is MethodGroupExpr)) {
5037                                         ml.Error118 ("method group");
5038                                         return null;
5039                                 }
5040
5041                                 if (ml == null) {
5042                                         Error (-6, "New invocation: Can not find a constructor for " +
5043                                                       "this argument list");
5044                                         return null;
5045                                 }
5046
5047                                 new_method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml, arguments, loc);
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                         } else {
5058                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
5059                                 ArrayList args = new ArrayList ();
5060
5061                                 if (arguments != null) {
5062                                         for (int i = 0; i < arg_count; i++)
5063                                                 args.Add (TypeManager.int32_type);
5064                                 }
5065
5066                                 Type [] arg_types = null;
5067
5068                                 if (args.Count > 0)
5069                                         arg_types = new Type [args.Count];
5070
5071                                 args.CopyTo (arg_types, 0);
5072
5073                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
5074                                                             arg_types);
5075
5076                                 if (new_method == null) {
5077                                         Error (-6, "New invocation: Can not find a constructor for " +
5078                                                       "this argument list");
5079                                         return null;
5080                                 }
5081
5082                                 eclass = ExprClass.Value;
5083                                 return this;
5084                         }
5085                 }
5086
5087                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
5088                 {
5089                         int factor;
5090                         byte [] data;
5091                         byte [] element;
5092                         int count = array_data.Count;
5093
5094                         if (underlying_type.IsEnum)
5095                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
5096
5097                         factor = GetTypeSize (underlying_type);
5098                         if (factor == 0)
5099                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
5100
5101                         data = new byte [(count * factor + 4) & ~3];
5102                         int idx = 0;
5103
5104                         for (int i = 0; i < count; ++i) {
5105                                 object v = array_data [i];
5106
5107                                 if (v is EnumConstant)
5108                                         v = ((EnumConstant) v).Child;
5109
5110                                 if (v is Constant && !(v is StringConstant))
5111                                         v = ((Constant) v).GetValue ();
5112                                 else {
5113                                         idx += factor;
5114                                         continue;
5115                                 }
5116
5117                                 if (underlying_type == TypeManager.int64_type){
5118                                         if (!(v is Expression)){
5119                                                 long val = (long) v;
5120
5121                                                 for (int j = 0; j < factor; ++j) {
5122                                                         data [idx + j] = (byte) (val & 0xFF);
5123                                                         val = (val >> 8);
5124                                                 }
5125                                         }
5126                                 } else if (underlying_type == TypeManager.uint64_type){
5127                                         if (!(v is Expression)){
5128                                                 ulong val = (ulong) v;
5129
5130                                                 for (int j = 0; j < factor; ++j) {
5131                                                         data [idx + j] = (byte) (val & 0xFF);
5132                                                         val = (val >> 8);
5133                                                 }
5134                                         }
5135                                 } else if (underlying_type == TypeManager.float_type) {
5136                                         if (!(v is Expression)){
5137                                                 element = BitConverter.GetBytes ((float) v);
5138
5139                                                 for (int j = 0; j < factor; ++j)
5140                                                         data [idx + j] = element [j];
5141                                         }
5142                                 } else if (underlying_type == TypeManager.double_type) {
5143                                         if (!(v is Expression)){
5144                                                 element = BitConverter.GetBytes ((double) v);
5145
5146                                                 for (int j = 0; j < factor; ++j)
5147                                                         data [idx + j] = element [j];
5148                                         }
5149                                 } else if (underlying_type == TypeManager.char_type){
5150                                         if (!(v is Expression)){
5151                                                 int val = (int) ((char) v);
5152
5153                                                 data [idx] = (byte) (val & 0xff);
5154                                                 data [idx+1] = (byte) (val >> 8);
5155                                         }
5156                                 } else if (underlying_type == TypeManager.short_type){
5157                                         if (!(v is Expression)){
5158                                                 int val = (int) ((short) v);
5159
5160                                                 data [idx] = (byte) (val & 0xff);
5161                                                 data [idx+1] = (byte) (val >> 8);
5162                                         }
5163                                 } else if (underlying_type == TypeManager.ushort_type){
5164                                         if (!(v is Expression)){
5165                                                 int val = (int) ((ushort) v);
5166
5167                                                 data [idx] = (byte) (val & 0xff);
5168                                                 data [idx+1] = (byte) (val >> 8);
5169                                         }
5170                                 } else if (underlying_type == TypeManager.int32_type) {
5171                                         if (!(v is Expression)){
5172                                                 int val = (int) v;
5173
5174                                                 data [idx]   = (byte) (val & 0xff);
5175                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
5176                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
5177                                                 data [idx+3] = (byte) (val >> 24);
5178                                         }
5179                                 } else if (underlying_type == TypeManager.uint32_type) {
5180                                         if (!(v is Expression)){
5181                                                 uint val = (uint) v;
5182
5183                                                 data [idx]   = (byte) (val & 0xff);
5184                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
5185                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
5186                                                 data [idx+3] = (byte) (val >> 24);
5187                                         }
5188                                 } else if (underlying_type == TypeManager.sbyte_type) {
5189                                         if (!(v is Expression)){
5190                                                 sbyte val = (sbyte) v;
5191                                                 data [idx] = (byte) val;
5192                                         }
5193                                 } else if (underlying_type == TypeManager.byte_type) {
5194                                         if (!(v is Expression)){
5195                                                 byte val = (byte) v;
5196                                                 data [idx] = (byte) val;
5197                                         }
5198                                 } else if (underlying_type == TypeManager.bool_type) {
5199                                         if (!(v is Expression)){
5200                                                 bool val = (bool) v;
5201                                                 data [idx] = (byte) (val ? 1 : 0);
5202                                         }
5203                                 } else if (underlying_type == TypeManager.decimal_type){
5204                                         if (!(v is Expression)){
5205                                                 int [] bits = Decimal.GetBits ((decimal) v);
5206                                                 int p = idx;
5207
5208                                                 for (int j = 0; j < 4; j++){
5209                                                         data [p++] = (byte) (bits [j] & 0xff);
5210                                                         data [p++] = (byte) ((bits [j] >> 8) & 0xff);
5211                                                         data [p++] = (byte) ((bits [j] >> 16) & 0xff);
5212                                                         data [p++] = (byte) (bits [j] >> 24);
5213                                                 }
5214                                         }
5215                                 } else
5216                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
5217
5218                                 idx += factor;
5219                         }
5220
5221                         return data;
5222                 }
5223
5224                 //
5225                 // Emits the initializers for the array
5226                 //
5227                 void EmitStaticInitializers (EmitContext ec, bool is_expression)
5228                 {
5229                         //
5230                         // First, the static data
5231                         //
5232                         FieldBuilder fb;
5233                         ILGenerator ig = ec.ig;
5234
5235                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
5236
5237                         fb = RootContext.MakeStaticData (data);
5238
5239                         if (is_expression)
5240                                 ig.Emit (OpCodes.Dup);
5241                         ig.Emit (OpCodes.Ldtoken, fb);
5242                         ig.Emit (OpCodes.Call,
5243                                  TypeManager.void_initializearray_array_fieldhandle);
5244                 }
5245
5246                 //
5247                 // Emits pieces of the array that can not be computed at compile
5248                 // time (variables and string locations).
5249                 //
5250                 // This always expect the top value on the stack to be the array
5251                 //
5252                 void EmitDynamicInitializers (EmitContext ec, bool is_expression)
5253                 {
5254                         ILGenerator ig = ec.ig;
5255                         int dims = bounds.Count;
5256                         int [] current_pos = new int [dims];
5257                         int top = array_data.Count;
5258                         LocalBuilder temp = ig.DeclareLocal (type);
5259
5260                         ig.Emit (OpCodes.Stloc, temp);
5261
5262                         MethodInfo set = null;
5263
5264                         if (dims != 1){
5265                                 Type [] args;
5266                                 ModuleBuilder mb = null;
5267                                 mb = CodeGen.ModuleBuilder;
5268                                 args = new Type [dims + 1];
5269
5270                                 int j;
5271                                 for (j = 0; j < dims; j++)
5272                                         args [j] = TypeManager.int32_type;
5273
5274                                 args [j] = array_element_type;
5275
5276                                 set = mb.GetArrayMethod (
5277                                         type, "Set",
5278                                         CallingConventions.HasThis | CallingConventions.Standard,
5279                                         TypeManager.void_type, args);
5280                         }
5281
5282                         for (int i = 0; i < top; i++){
5283
5284                                 Expression e = null;
5285
5286                                 if (array_data [i] is Expression)
5287                                         e = (Expression) array_data [i];
5288
5289                                 if (e != null) {
5290                                         //
5291                                         // Basically we do this for string literals and
5292                                         // other non-literal expressions
5293                                         //
5294                                         if (e is StringConstant || !(e is Constant) ||
5295                                             num_automatic_initializers <= 2) {
5296                                                 Type etype = e.Type;
5297
5298                                                 ig.Emit (OpCodes.Ldloc, temp);
5299
5300                                                 for (int idx = 0; idx < dims; idx++)
5301                                                         IntConstant.EmitInt (ig, current_pos [idx]);
5302
5303                                                 //
5304                                                 // If we are dealing with a struct, get the
5305                                                 // address of it, so we can store it.
5306                                                 //
5307                                                 if ((dims == 1) &&
5308                                                     etype.IsSubclassOf (TypeManager.value_type) &&
5309                                                     (!TypeManager.IsBuiltinType (etype) ||
5310                                                      etype == TypeManager.decimal_type)) {
5311                                                         if (e is New){
5312                                                                 New n = (New) e;
5313
5314                                                                 //
5315                                                                 // Let new know that we are providing
5316                                                                 // the address where to store the results
5317                                                                 //
5318                                                                 n.DisableTemporaryValueType ();
5319                                                         }
5320
5321                                                         ig.Emit (OpCodes.Ldelema, etype);
5322                                                 }
5323
5324                                                 e.Emit (ec);
5325
5326                                                 if (dims == 1)
5327                                                         ArrayAccess.EmitStoreOpcode (ig, array_element_type);
5328                                                 else
5329                                                         ig.Emit (OpCodes.Call, set);
5330                                         }
5331                                 }
5332
5333                                 //
5334                                 // Advance counter
5335                                 //
5336                                 for (int j = dims - 1; j >= 0; j--){
5337                                         current_pos [j]++;
5338                                         if (current_pos [j] < (int) bounds [j])
5339                                                 break;
5340                                         current_pos [j] = 0;
5341                                 }
5342                         }
5343
5344                         if (is_expression)
5345                                 ig.Emit (OpCodes.Ldloc, temp);
5346                 }
5347
5348                 void EmitArrayArguments (EmitContext ec)
5349                 {
5350                         ILGenerator ig = ec.ig;
5351
5352                         foreach (Argument a in arguments) {
5353                                 Type atype = a.Type;
5354                                 a.Emit (ec);
5355
5356                                 if (atype == TypeManager.uint64_type)
5357                                         ig.Emit (OpCodes.Conv_Ovf_U4);
5358                                 else if (atype == TypeManager.int64_type)
5359                                         ig.Emit (OpCodes.Conv_Ovf_I4);
5360                         }
5361                 }
5362
5363                 void DoEmit (EmitContext ec, bool is_statement)
5364                 {
5365                         ILGenerator ig = ec.ig;
5366
5367                         EmitArrayArguments (ec);
5368                         if (is_one_dimensional)
5369                                 ig.Emit (OpCodes.Newarr, array_element_type);
5370                         else {
5371                                 if (is_builtin_type)
5372                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
5373                                 else
5374                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
5375                         }
5376
5377                         if (initializers != null){
5378                                 //
5379                                 // FIXME: Set this variable correctly.
5380                                 //
5381                                 bool dynamic_initializers = true;
5382
5383                                 if (underlying_type != TypeManager.string_type &&
5384                                     underlying_type != TypeManager.object_type) {
5385                                         if (num_automatic_initializers > 2)
5386                                                 EmitStaticInitializers (ec, dynamic_initializers || !is_statement);
5387                                 }
5388
5389                                 if (dynamic_initializers)
5390                                         EmitDynamicInitializers (ec, !is_statement);
5391                         }
5392                 }
5393
5394                 public override void Emit (EmitContext ec)
5395                 {
5396                         DoEmit (ec, false);
5397                 }
5398
5399                 public override void EmitStatement (EmitContext ec)
5400                 {
5401                         DoEmit (ec, true);
5402                 }
5403
5404         }
5405
5406         /// <summary>
5407         ///   Represents the 'this' construct
5408         /// </summary>
5409         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
5410
5411                 Block block;
5412                 VariableInfo vi;
5413
5414                 public This (Block block, Location loc)
5415                 {
5416                         this.loc = loc;
5417                         this.block = block;
5418                 }
5419
5420                 public This (Location loc)
5421                 {
5422                         this.loc = loc;
5423                 }
5424
5425                 public bool IsAssigned (EmitContext ec, Location loc)
5426                 {
5427                         if (vi == null)
5428                                 return true;
5429
5430                         return vi.IsAssigned (ec, loc);
5431                 }
5432
5433                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
5434                 {
5435                         if (vi == null)
5436                                 return true;
5437
5438                         return vi.IsFieldAssigned (ec, field_name, loc);
5439                 }
5440
5441                 public void SetAssigned (EmitContext ec)
5442                 {
5443                         if (vi != null)
5444                                 vi.SetAssigned (ec);
5445                 }
5446
5447                 public void SetFieldAssigned (EmitContext ec, string field_name)
5448                 {
5449                         if (vi != null)
5450                                 vi.SetFieldAssigned (ec, field_name);
5451                 }
5452
5453                 public override Expression DoResolve (EmitContext ec)
5454                 {
5455                         eclass = ExprClass.Variable;
5456                         type = ec.ContainerType;
5457
5458                         if (ec.IsStatic){
5459                                 Error (26, "Keyword this not valid in static code");
5460                                 return null;
5461                         }
5462
5463                         if (block != null)
5464                                 vi = block.ThisVariable;
5465
5466                         return this;
5467                 }
5468
5469                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5470                 {
5471                         DoResolve (ec);
5472
5473                         VariableInfo vi = ec.CurrentBlock.ThisVariable;
5474                         if (vi != null)
5475                                 vi.SetAssigned (ec);
5476
5477                         if (ec.TypeContainer is Class){
5478                                 Error (1604, "Cannot assign to 'this'");
5479                                 return null;
5480                         }
5481
5482                         return this;
5483                 }
5484
5485                 public override void Emit (EmitContext ec)
5486                 {
5487                         ILGenerator ig = ec.ig;
5488
5489                         ig.Emit (OpCodes.Ldarg_0);
5490                         if (ec.TypeContainer is Struct)
5491                                 ig.Emit (OpCodes.Ldobj, type);
5492                 }
5493
5494                 public void EmitAssign (EmitContext ec, Expression source)
5495                 {
5496                         ILGenerator ig = ec.ig;
5497
5498                         if (ec.TypeContainer is Struct){
5499                                 ig.Emit (OpCodes.Ldarg_0);
5500                                 source.Emit (ec);
5501                                 ig.Emit (OpCodes.Stobj, type);
5502                         } else {
5503                                 source.Emit (ec);
5504                                 ig.Emit (OpCodes.Starg, 0);
5505                         }
5506                 }
5507
5508                 public void AddressOf (EmitContext ec, AddressOp mode)
5509                 {
5510                         ec.ig.Emit (OpCodes.Ldarg_0);
5511
5512                         // FIMXE
5513                         // FIGURE OUT WHY LDARG_S does not work
5514                         //
5515                         // consider: struct X { int val; int P { set { val = value; }}}
5516                         //
5517                         // Yes, this looks very bad. Look at 'NOTAS' for
5518                         // an explanation.
5519                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
5520                 }
5521         }
5522
5523         /// <summary>
5524         ///   Implements the typeof operator
5525         /// </summary>
5526         public class TypeOf : Expression {
5527                 public readonly Expression QueriedType;
5528                 Type typearg;
5529
5530                 public TypeOf (Expression queried_type, Location l)
5531                 {
5532                         QueriedType = queried_type;
5533                         loc = l;
5534                 }
5535
5536                 public override Expression DoResolve (EmitContext ec)
5537                 {
5538                         typearg = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5539
5540                         if (typearg == null)
5541                                 return null;
5542
5543                         type = TypeManager.type_type;
5544                         eclass = ExprClass.Type;
5545                         return this;
5546                 }
5547
5548                 public override void Emit (EmitContext ec)
5549                 {
5550                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
5551                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
5552                 }
5553
5554                 public Type TypeArg {
5555                         get { return typearg; }
5556                 }
5557         }
5558
5559         /// <summary>
5560         ///   Implements the sizeof expression
5561         /// </summary>
5562         public class SizeOf : Expression {
5563                 public readonly Expression QueriedType;
5564                 Type type_queried;
5565
5566                 public SizeOf (Expression queried_type, Location l)
5567                 {
5568                         this.QueriedType = queried_type;
5569                         loc = l;
5570                 }
5571
5572                 public override Expression DoResolve (EmitContext ec)
5573                 {
5574                         if (!ec.InUnsafe) {
5575                                 Error (233, "Sizeof may only be used in an unsafe context " +
5576                                        "(consider using System.Runtime.InteropServices.Marshal.Sizeof");
5577                                 return null;
5578                         }
5579
5580                         type_queried = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5581                         if (type_queried == null)
5582                                 return null;
5583
5584                         if (!TypeManager.IsUnmanagedType (type_queried)){
5585                                 Report.Error (208, "Cannot take the size of an unmanaged type (" + TypeManager.MonoBASIC_Name (type_queried) + ")");
5586                                 return null;
5587                         }
5588
5589                         type = TypeManager.int32_type;
5590                         eclass = ExprClass.Value;
5591                         return this;
5592                 }
5593
5594                 public override void Emit (EmitContext ec)
5595                 {
5596                         int size = GetTypeSize (type_queried);
5597
5598                         if (size == 0)
5599                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
5600                         else
5601                                 IntConstant.EmitInt (ec.ig, size);
5602                 }
5603         }
5604
5605         /// <summary>
5606         ///   Implements the member access expression
5607         /// </summary>
5608         public class MemberAccess : Expression, ITypeExpression {
5609                 public readonly string Identifier;
5610                 Expression expr;
5611                 Expression member_lookup;
5612
5613                 public MemberAccess (Expression expr, string id, Location l)
5614                 {
5615                         this.expr = expr;
5616                         Identifier = id;
5617                         loc = l;
5618                 }
5619
5620                 public Expression Expr {
5621                         get {
5622                                 return expr;
5623                         }
5624                 }
5625
5626                 static void error176 (Location loc, string name)
5627                 {
5628                         Report.Error (176, loc, "Static member '" +
5629                                       name + "' cannot be accessed " +
5630                                       "with an instance reference, qualify with a " +
5631                                       "type name instead");
5632                 }
5633
5634                 static bool IdenticalNameAndTypeName (EmitContext ec, Expression left_original, Location loc)
5635                 {
5636                         if (left_original == null)
5637                                 return false;
5638
5639                         if (!(left_original is SimpleName))
5640                                 return false;
5641
5642                         SimpleName sn = (SimpleName) left_original;
5643
5644                         Type t = RootContext.LookupType (ec.DeclSpace, sn.Name, true, loc);
5645                         if (t != null)
5646                                 return true;
5647
5648                         return false;
5649                 }
5650
5651                 public static Expression ResolveMemberAccess (EmitContext ec, Expression member_lookup,
5652                                                               Expression left, Location loc,
5653                                                               Expression left_original)
5654                 {
5655                         bool left_is_type, left_is_explicit;
5656
5657                         // If 'left' is null, then we're called from SimpleNameResolve and this is
5658                         // a member in the currently defining class.
5659                         if (left == null) {
5660                                 left_is_type = ec.IsStatic || ec.IsFieldInitializer;
5661                                 left_is_explicit = false;
5662
5663                                 // Implicitly default to 'this' unless we're static.
5664                                 if (!ec.IsStatic && !ec.IsFieldInitializer && !ec.InEnumContext)
5665                                         left = ec.This;
5666                         } else {
5667                                 left_is_type = left is TypeExpr;
5668                                 left_is_explicit = true;
5669                         }
5670
5671                         if (member_lookup is FieldExpr){
5672                                 FieldExpr fe = (FieldExpr) member_lookup;
5673                                 FieldInfo fi = fe.FieldInfo;
5674                                 Type decl_type = fi.DeclaringType;
5675
5676                                 if (fi is FieldBuilder) {
5677                                         Const c = TypeManager.LookupConstant ((FieldBuilder) fi);
5678
5679                                         if (c != null) {
5680                                                 object o = c.LookupConstantValue (ec);
5681                                                 object real_value = ((Constant) c.Expr).GetValue ();
5682
5683                                                 return Constantify (real_value, fi.FieldType);
5684                                         }
5685                                 }
5686
5687                                 if (fi.IsLiteral) {
5688                                         Type t = fi.FieldType;
5689
5690                                         object o;
5691
5692                                         if (fi is FieldBuilder)
5693                                                 o = TypeManager.GetValue ((FieldBuilder) fi);
5694                                         else
5695                                                 o = fi.GetValue (fi);
5696
5697                                         if (decl_type.IsSubclassOf (TypeManager.enum_type)) {
5698                                                 if (left_is_explicit && !left_is_type &&
5699                                                     !IdenticalNameAndTypeName (ec, left_original, loc)) {
5700                                                         error176 (loc, fe.FieldInfo.Name);
5701                                                         return null;
5702                                                 }
5703
5704                                                 Expression enum_member = MemberLookup (
5705                                                         ec, decl_type, "value__", MemberTypes.Field,
5706                                                         AllBindingFlags, loc);
5707
5708                                                 Enum en = TypeManager.LookupEnum (decl_type);
5709
5710                                                 Constant c;
5711                                                 if (en != null)
5712                                                         c = Constantify (o, en.UnderlyingType);
5713                                                 else
5714                                                         c = Constantify (o, enum_member.Type);
5715
5716                                                 return new EnumConstant (c, decl_type);
5717                                         }
5718
5719                                         Expression exp = Constantify (o, t);
5720
5721                                         if (left_is_explicit && !left_is_type) {
5722                                                 error176 (loc, fe.FieldInfo.Name);
5723                                                 return null;
5724                                         }
5725
5726                                         return exp;
5727                                 }
5728
5729                                 if (fi.FieldType.IsPointer && !ec.InUnsafe){
5730                                         UnsafeError (loc);
5731                                         return null;
5732                                 }
5733                         }
5734
5735
5736                         if (member_lookup is IMemberExpr) {
5737                                 IMemberExpr me = (IMemberExpr) member_lookup;
5738
5739                                 if (left_is_type){
5740                                         MethodGroupExpr mg = me as MethodGroupExpr;
5741                                         if ((mg != null) && left_is_explicit && left.Type.IsInterface)
5742                                                 mg.IsExplicitImpl = left_is_explicit;
5743
5744                                         if (!me.IsStatic){
5745                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5746                                                         return member_lookup;
5747
5748                                                 SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
5749                                                 return null;
5750                                         }
5751
5752                                 } else {
5753                                         if (!me.IsInstance){
5754                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5755                                                         return member_lookup;
5756
5757                                                 /*if (left_is_explicit) {
5758                                                         error176 (loc, me.Name);
5759                                                         return null;
5760                                                 }*/
5761                                         }
5762
5763                                         //
5764                                         // Since we can not check for instance objects in SimpleName,
5765                                         // becaue of the rule that allows types and variables to share
5766                                         // the name (as long as they can be de-ambiguated later, see
5767                                         // IdenticalNameAndTypeName), we have to check whether left
5768                                         // is an instance variable in a static context
5769                                         //
5770                                         // However, if the left-hand value is explicitly given, then
5771                                         // it is already our instance expression, so we aren't in
5772                                         // static context.
5773                                         //
5774
5775                                         if (ec.IsStatic && !left_is_explicit && left is IMemberExpr){
5776                                                 IMemberExpr mexp = (IMemberExpr) left;
5777
5778                                                 if (!mexp.IsStatic){
5779                                                         SimpleName.Error_ObjectRefRequired (ec, loc, mexp.Name);
5780                                                         return null;
5781                                                 }
5782                                         }
5783
5784                                         me.InstanceExpression = left;
5785                                 }
5786
5787                                 return member_lookup;
5788                         }
5789
5790                         if (member_lookup is TypeExpr){
5791                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5792                                 return member_lookup;
5793                         }
5794
5795                         Console.WriteLine ("Left is: " + left);
5796                         Report.Error (-100, loc, "Support for [" + member_lookup + "] is not present yet");
5797                         Environment.Exit (0);
5798                         return null;
5799                 }
5800
5801                 public Expression DoResolve (EmitContext ec, Expression right_side, ResolveFlags flags)
5802                 {
5803                         if (type != null)
5804                                 throw new Exception ();
5805                         //
5806                         // Resolve the expression with flow analysis turned off, we'll do the definite
5807                         // assignment checks later.  This is because we don't know yet what the expression
5808                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
5809                         // definite assignment check on the actual field and not on the whole struct.
5810                         //
5811
5812                         Expression original = expr;
5813                         expr = expr.Resolve (ec, flags | ResolveFlags.DisableFlowAnalysis);
5814
5815                         if (expr == null)
5816                                 return null;
5817
5818                         if (expr is SimpleName){
5819                                 SimpleName child_expr = (SimpleName) expr;
5820
5821                                 Expression new_expr = new SimpleName (child_expr.Name + "." + Identifier, loc);
5822
5823                                 if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
5824                                         return new_expr.Resolve (ec, flags);
5825                                 else
5826                                         return new_expr.Resolve (ec, flags | ResolveFlags.MethodGroup | ResolveFlags.VariableOrValue);
5827                         }
5828
5829                         int errors = Report.Errors;
5830
5831                         Type expr_type = expr.Type;
5832
5833                         if (expr is TypeExpr){
5834                                 //FIXME: add access level check
5835                                 //if (!ec.DeclSpace.CheckAccessLevel (expr_type)) {
5836                                 //              Error (30390, "'" + TypeManager.MonoBASIC_Name (expr_type) + "' " +
5837                                 //                     "is inaccessible because of its protection level");
5838                                 //      return null;
5839                                 //}
5840
5841                                 if (expr_type == TypeManager.enum_type || expr_type.IsSubclassOf (TypeManager.enum_type)){
5842                                         Enum en = TypeManager.LookupEnum (expr_type);
5843
5844                                         if (en != null) {
5845                                                 object value = en.LookupEnumValue (ec, Identifier, loc);
5846
5847                                                 if (value != null){
5848                                                         Constant c = Constantify (value, en.UnderlyingType);
5849                                                         return new EnumConstant (c, expr_type);
5850                                                 }
5851                                         }
5852                                 }
5853                         }
5854
5855                         if (expr_type.IsPointer){
5856                                 Error (23, "The '.' operator can not be applied to pointer operands (" +
5857                                        TypeManager.MonoBASIC_Name (expr_type) + ")");
5858                                 return null;
5859                         }
5860
5861                         member_lookup = MemberLookup (ec, expr_type, Identifier, loc);
5862
5863                         if (member_lookup == null)
5864                         {
5865                                 // Error has already been reported.
5866                                 if (errors < Report.Errors)
5867                                         return null;
5868
5869                                 //
5870                                 // Try looking the member up from the same type, if we find
5871                                 // it, we know that the error was due to limited visibility
5872                                 //
5873                                 object lookup = TypeManager.MemberLookup (
5874                                         expr_type, expr_type, AllMemberTypes, AllBindingFlags |
5875                                         BindingFlags.NonPublic, Identifier);
5876
5877                                 if (lookup == null)
5878                                         Error (30456, "'" + expr_type + "' does not contain a definition for '" + Identifier + "'");
5879                                 else
5880                                 {
5881                                         if ((expr_type != ec.ContainerType) &&
5882                                                  ec.ContainerType.IsSubclassOf (expr_type))
5883                                         {
5884
5885                                                 // Although a derived class can access protected members of
5886                                                 // its base class it cannot do so through an instance of the
5887                                                 // base class (CS1540).  If the expr_type is a parent of the
5888                                                 // ec.ContainerType and the lookup succeeds with the latter one,
5889                                                 // then we are in this situation.
5890
5891                                                 lookup = TypeManager.MemberLookup(
5892                                                                         ec.ContainerType, ec.ContainerType, AllMemberTypes,
5893                                                                         AllBindingFlags, Identifier);
5894
5895                                                 if (lookup != null)
5896                                                         Error (1540, "Cannot access protected member '" +
5897                                                        expr_type + "." + Identifier + "' " +
5898                                                        "via a qualifier of type '" + TypeManager.MonoBASIC_Name (expr_type) + "'; the " +
5899                                                        "qualifier must be of type '" + TypeManager.MonoBASIC_Name (ec.ContainerType) + "' " +
5900                                                        "(or derived from it)");
5901                                                 else
5902                                                         Error (30390, "'" + expr_type + "." + Identifier + "' " +
5903                                                        "is inaccessible because of its protection level");
5904                                         } else
5905                                                 Error (30390, "'" + expr_type + "." + Identifier + "' " +
5906                                                "is inaccessible because of its protection level");
5907                                 }
5908                                 return null;
5909                         }
5910
5911                         if ((expr is TypeExpr) && (expr_type.IsSubclassOf (TypeManager.enum_type)))     {
5912                                 Enum en = TypeManager.LookupEnum (expr_type);
5913
5914                                 if (en != null) {
5915                                         object value = en.LookupEnumValue (ec, Identifier, loc);
5916                                         expr_type = TypeManager.int32_type;
5917                                         if (value != null) {
5918                                                 Constant c = Constantify (value, en.UnderlyingType);
5919                                                 return new EnumConstant (c, en.UnderlyingType);
5920                                         }
5921                                 }
5922                         }
5923
5924                         if (member_lookup is TypeExpr){
5925                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5926
5927                                 return member_lookup;
5928                         } else if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
5929                                 return null;
5930
5931                         member_lookup = ResolveMemberAccess (ec, member_lookup, expr, loc, original);
5932                         if (member_lookup == null)
5933                                 return null;
5934
5935                         // The following DoResolve/DoResolveLValue will do the definite assignment
5936                         // check.
5937                         if (right_side != null)
5938                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
5939                         else
5940                                 member_lookup = member_lookup.DoResolve (ec);
5941
5942                         return member_lookup;
5943                 }
5944
5945                 public override Expression DoResolve (EmitContext ec)
5946                 {
5947                         return DoResolve (ec, null, ResolveFlags.VariableOrValue |
5948                                           ResolveFlags.SimpleName | ResolveFlags.Type);
5949                 }
5950
5951                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5952                 {
5953                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue |
5954                                           ResolveFlags.SimpleName | ResolveFlags.Type);
5955                 }
5956
5957                 public Expression DoResolveType (EmitContext ec)
5958                 {
5959                         return DoResolve (ec, null, ResolveFlags.Type);
5960                 }
5961
5962                 public override void Emit (EmitContext ec)
5963                 {
5964                         throw new Exception ("Should not happen");
5965                 }
5966
5967                 public override string ToString ()
5968                 {
5969                         return expr + "." + Identifier;
5970                 }
5971         }
5972
5973
5974
5975         /// <summary>
5976         ///   Implements checked expressions
5977         /// </summary>
5978         public class CheckedExpr : Expression {
5979
5980                 public Expression Expr;
5981
5982                 public CheckedExpr (Expression e, Location l)
5983                 {
5984                         Expr = e;
5985                         loc = l;
5986                 }
5987
5988                 public override Expression DoResolve (EmitContext ec)
5989                 {
5990                         bool last_const_check = ec.ConstantCheckState;
5991
5992                         ec.ConstantCheckState = true;
5993                         Expr = Expr.Resolve (ec);
5994                         ec.ConstantCheckState = last_const_check;
5995
5996                         if (Expr == null)
5997                                 return null;
5998
5999                         if (Expr is Constant)
6000                                 return Expr;
6001
6002                         eclass = Expr.eclass;
6003                         type = Expr.Type;
6004                         return this;
6005                 }
6006
6007                 public override void Emit (EmitContext ec)
6008                 {
6009                         bool last_check = ec.CheckState;
6010                         bool last_const_check = ec.ConstantCheckState;
6011
6012                         ec.CheckState = true;
6013                         ec.ConstantCheckState = true;
6014                         Expr.Emit (ec);
6015                         ec.CheckState = last_check;
6016                         ec.ConstantCheckState = last_const_check;
6017                 }
6018
6019         }
6020
6021         /// <summary>
6022         ///   Implements the unchecked expression
6023         /// </summary>
6024         public class UnCheckedExpr : Expression {
6025
6026                 public Expression Expr;
6027
6028                 public UnCheckedExpr (Expression e, Location l)
6029                 {
6030                         Expr = e;
6031                         loc = l;
6032                 }
6033
6034                 public override Expression DoResolve (EmitContext ec)
6035                 {
6036                         bool last_const_check = ec.ConstantCheckState;
6037
6038                         ec.ConstantCheckState = false;
6039                         Expr = Expr.Resolve (ec);
6040                         ec.ConstantCheckState = last_const_check;
6041
6042                         if (Expr == null)
6043                                 return null;
6044
6045                         if (Expr is Constant)
6046                                 return Expr;
6047
6048                         eclass = Expr.eclass;
6049                         type = Expr.Type;
6050                         return this;
6051                 }
6052
6053                 public override void Emit (EmitContext ec)
6054                 {
6055                         bool last_check = ec.CheckState;
6056                         bool last_const_check = ec.ConstantCheckState;
6057
6058                         ec.CheckState = false;
6059                         ec.ConstantCheckState = false;
6060                         Expr.Emit (ec);
6061                         ec.CheckState = last_check;
6062                         ec.ConstantCheckState = last_const_check;
6063                 }
6064
6065         }
6066
6067         /// <summary>
6068         ///   An Element Access expression.
6069         ///
6070         ///   During semantic analysis these are transformed into
6071         ///   IndexerAccess or ArrayAccess
6072         /// </summary>
6073         public class ElementAccess : Expression {
6074                 public ArrayList  Arguments;
6075                 public Expression Expr;
6076
6077                 public ElementAccess (Expression e, ArrayList e_list, Location l)
6078                 {
6079                         Expr = e;
6080
6081                         loc  = l;
6082
6083                         if (e_list == null)
6084                                 return;
6085
6086                         Arguments = new ArrayList ();
6087                         foreach (Expression tmp in e_list)
6088                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
6089
6090                 }
6091
6092                 bool CommonResolve (EmitContext ec)
6093                 {
6094                         Expr = Expr.Resolve (ec);
6095
6096                         if (Expr == null)
6097                                 return false;
6098
6099                         if (Arguments == null)
6100                                 return false;
6101
6102                         foreach (Argument a in Arguments){
6103                                 if (!a.Resolve (ec, loc))
6104                                         return false;
6105                         }
6106
6107                         return true;
6108                 }
6109
6110                 Expression MakePointerAccess ()
6111                 {
6112                         Type t = Expr.Type;
6113
6114                         if (t == TypeManager.void_ptr_type){
6115                                 Error (
6116                                         242,
6117                                         "The array index operation is not valid for void pointers");
6118                                 return null;
6119                         }
6120                         if (Arguments.Count != 1){
6121                                 Error (
6122                                         196,
6123                                         "A pointer must be indexed by a single value");
6124                                 return null;
6125                         }
6126                         Expression p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr,
6127                                                               t, loc);
6128                         return new Indirection (p, loc);
6129                 }
6130
6131                 public override Expression DoResolve (EmitContext ec)
6132                 {
6133                         if (!CommonResolve (ec))
6134                                 return null;
6135
6136                         //
6137                         // We perform some simple tests, and then to "split" the emit and store
6138                         // code we create an instance of a different class, and return that.
6139                         //
6140                         // I am experimenting with this pattern.
6141                         //
6142                         Type t = Expr.Type;
6143
6144                         if (t.IsArray)
6145                                 return (new ArrayAccess (this, loc)).Resolve (ec);
6146                         else if (t.IsPointer)
6147                                 return MakePointerAccess ();
6148                         else
6149                                 return (new IndexerAccess (this, loc)).Resolve (ec);
6150                 }
6151
6152                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6153                 {
6154                         if (!CommonResolve (ec))
6155                                 return null;
6156
6157                         Type t = Expr.Type;
6158                         if (t.IsArray)
6159                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
6160                         else if (t.IsPointer)
6161                                 return MakePointerAccess ();
6162                         else
6163                                 return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
6164                 }
6165
6166                 public override void Emit (EmitContext ec)
6167                 {
6168                         throw new Exception ("Should never be reached");
6169                 }
6170         }
6171
6172         /// <summary>
6173         ///   Implements array access
6174         /// </summary>
6175         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
6176                 //
6177                 // Points to our "data" repository
6178                 //
6179                 ElementAccess ea;
6180
6181                 LocalTemporary [] cached_locations;
6182
6183                 public ArrayAccess (ElementAccess ea_data, Location l)
6184                 {
6185                         ea = ea_data;
6186                         eclass = ExprClass.Variable;
6187                         loc = l;
6188                 }
6189
6190                 public override Expression DoResolve (EmitContext ec)
6191                 {
6192                         ExprClass eclass = ea.Expr.eclass;
6193
6194 #if false
6195                         // As long as the type is valid
6196                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
6197                               eclass == ExprClass.Value)) {
6198                                 ea.Expr.Error118 ("variable or value");
6199                                 return null;
6200                         }
6201 #endif
6202
6203                         Type t = ea.Expr.Type;
6204 /*
6205                         if (t == typeof (System.Object))
6206                         {
6207                                 // We can't resolve now, but we
6208                                 // have to try to access the array with a call
6209                                 // to LateIndexGet in the runtime
6210
6211                                 Expression lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexGet", Location.Null);
6212                                 Expression obj_type = Mono.MonoBASIC.Parser.DecomposeQI("System.Object", Location.Null);
6213                                 ArrayList adims = new ArrayList();
6214
6215                                 ArrayList ainit = new ArrayList();
6216                                 foreach (Argument a in ea.Arguments)
6217                                         ainit.Add ((Expression) a.Expr);
6218
6219                                 adims.Add ((Expression) new IntLiteral (ea.Arguments.Count));
6220
6221                                 Expression oace = new ArrayCreation (obj_type, adims, "", ainit, Location.Null);
6222
6223                                 ArrayList args = new ArrayList();
6224                                 args.Add (new Argument(ea.Expr, Argument.AType.Expression));
6225                                 args.Add (new Argument(oace, Argument.AType.Expression));
6226                                 args.Add (new Argument(NullLiteral.Null, Argument.AType.Expression));
6227
6228                                 Expression lig_call = new Invocation (lig_call_expr, args, Location.Null);
6229                                 lig_call = lig_call.Resolve(ec);
6230                                 return lig_call;
6231                         }
6232 */
6233                         if (t.GetArrayRank () != ea.Arguments.Count){
6234                                 ea.Error (22,
6235                                           "Incorrect number of indexes for array " +
6236                                           " expected: " + t.GetArrayRank () + " got: " +
6237                                           ea.Arguments.Count);
6238                                 return null;
6239                         }
6240                         type = TypeManager.TypeToCoreType (t.GetElementType ());
6241                         if (type.IsPointer && !ec.InUnsafe){
6242                                 UnsafeError (ea.Location);
6243                                 return null;
6244                         }
6245
6246                         foreach (Argument a in ea.Arguments){
6247                                 Type argtype = a.Type;
6248
6249                                 if (argtype == TypeManager.int32_type ||
6250                                     argtype == TypeManager.uint32_type ||
6251                                     argtype == TypeManager.int64_type ||
6252                                     argtype == TypeManager.uint64_type)
6253                                         continue;
6254
6255                                 //
6256                                 // Mhm.  This is strage, because the Argument.Type is not the same as
6257                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
6258                                 //
6259                                 // Wonder if I will run into trouble for this.
6260                                 //
6261                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
6262                                 if (a.Expr == null)
6263                                         return null;
6264                         }
6265
6266                         eclass = ExprClass.Variable;
6267
6268                         return this;
6269                 }
6270
6271                 /// <summary>
6272                 ///    Emits the right opcode to load an object of Type 't'
6273                 ///    from an array of T
6274                 /// </summary>
6275                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
6276                 {
6277                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
6278                                 ig.Emit (OpCodes.Ldelem_U1);
6279                         else if (type == TypeManager.sbyte_type)
6280                                 ig.Emit (OpCodes.Ldelem_I1);
6281                         else if (type == TypeManager.short_type)
6282                                 ig.Emit (OpCodes.Ldelem_I2);
6283                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
6284                                 ig.Emit (OpCodes.Ldelem_U2);
6285                         else if (type == TypeManager.int32_type)
6286                                 ig.Emit (OpCodes.Ldelem_I4);
6287                         else if (type == TypeManager.uint32_type)
6288                                 ig.Emit (OpCodes.Ldelem_U4);
6289                         else if (type == TypeManager.uint64_type)
6290                                 ig.Emit (OpCodes.Ldelem_I8);
6291                         else if (type == TypeManager.int64_type)
6292                                 ig.Emit (OpCodes.Ldelem_I8);
6293                         else if (type == TypeManager.float_type)
6294                                 ig.Emit (OpCodes.Ldelem_R4);
6295                         else if (type == TypeManager.double_type)
6296                                 ig.Emit (OpCodes.Ldelem_R8);
6297                         else if (type == TypeManager.intptr_type)
6298                                 ig.Emit (OpCodes.Ldelem_I);
6299                         else if (type.IsValueType){
6300                                 ig.Emit (OpCodes.Ldelema, type);
6301                                 ig.Emit (OpCodes.Ldobj, type);
6302                         } else
6303                                 ig.Emit (OpCodes.Ldelem_Ref);
6304                 }
6305
6306                 /// <summary>
6307                 ///    Emits the right opcode to store an object of Type 't'
6308                 ///    from an array of T.
6309                 /// </summary>
6310                 static public void EmitStoreOpcode (ILGenerator ig, Type t)
6311                 {
6312                         t = TypeManager.TypeToCoreType (t);
6313                         if (TypeManager.IsEnumType (t) && t != TypeManager.enum_type)
6314                                 t = TypeManager.EnumToUnderlying (t);
6315                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
6316                             t == TypeManager.bool_type)
6317                                 ig.Emit (OpCodes.Stelem_I1);
6318                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type || t == TypeManager.char_type)
6319                                 ig.Emit (OpCodes.Stelem_I2);
6320                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
6321                                 ig.Emit (OpCodes.Stelem_I4);
6322                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
6323                                 ig.Emit (OpCodes.Stelem_I8);
6324                         else if (t == TypeManager.float_type)
6325                                 ig.Emit (OpCodes.Stelem_R4);
6326                         else if (t == TypeManager.double_type)
6327                                 ig.Emit (OpCodes.Stelem_R8);
6328                         else if (t == TypeManager.intptr_type)
6329                                 ig.Emit (OpCodes.Stelem_I);
6330                         else if (t.IsValueType){
6331                                 ig.Emit (OpCodes.Stobj, t);
6332                         } else
6333                                 ig.Emit (OpCodes.Stelem_Ref);
6334                 }
6335
6336                 MethodInfo FetchGetMethod ()
6337                 {
6338                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6339                         int arg_count = ea.Arguments.Count;
6340                         Type [] args = new Type [arg_count];
6341                         MethodInfo get;
6342
6343                         for (int i = 0; i < arg_count; i++){
6344                                 //args [i++] = a.Type;
6345                                 args [i] = TypeManager.int32_type;
6346                         }
6347
6348                         get = mb.GetArrayMethod (
6349                                 ea.Expr.Type, "Get",
6350                                 CallingConventions.HasThis |
6351                                 CallingConventions.Standard,
6352                                 type, args);
6353                         return get;
6354                 }
6355
6356
6357                 MethodInfo FetchAddressMethod ()
6358                 {
6359                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6360                         int arg_count = ea.Arguments.Count;
6361                         Type [] args = new Type [arg_count];
6362                         MethodInfo address;
6363                         string ptr_type_name;
6364                         Type ret_type;
6365
6366                         ptr_type_name = type.FullName + "&";
6367                         ret_type = Type.GetType (ptr_type_name);
6368
6369                         //
6370                         // It is a type defined by the source code we are compiling
6371                         //
6372                         if (ret_type == null){
6373                                 ret_type = mb.GetType (ptr_type_name);
6374                         }
6375
6376                         for (int i = 0; i < arg_count; i++){
6377                                 //args [i++] = a.Type;
6378                                 args [i] = TypeManager.int32_type;
6379                         }
6380
6381                         address = mb.GetArrayMethod (
6382                                 ea.Expr.Type, "Address",
6383                                 CallingConventions.HasThis |
6384                                 CallingConventions.Standard,
6385                                 ret_type, args);
6386
6387                         return address;
6388                 }
6389
6390                 //
6391                 // Load the array arguments into the stack.
6392                 //
6393                 // If we have been requested to cache the values (cached_locations array
6394                 // initialized), then load the arguments the first time and store them
6395                 // in locals.  otherwise load from local variables.
6396                 //
6397                 void LoadArrayAndArguments (EmitContext ec)
6398                 {
6399                         ILGenerator ig = ec.ig;
6400
6401                         if (cached_locations == null){
6402                                 ea.Expr.Emit (ec);
6403                                 foreach (Argument a in ea.Arguments){
6404                                         Type argtype = a.Expr.Type;
6405
6406                                         a.Expr.Emit (ec);
6407
6408                                         if (argtype == TypeManager.int64_type)
6409                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6410                                         else if (argtype == TypeManager.uint64_type)
6411                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6412                                 }
6413                                 return;
6414                         }
6415
6416                         if (cached_locations [0] == null){
6417                                 cached_locations [0] = new LocalTemporary (ec, ea.Expr.Type);
6418                                 ea.Expr.Emit (ec);
6419                                 ig.Emit (OpCodes.Dup);
6420                                 cached_locations [0].Store (ec);
6421
6422                                 int j = 1;
6423
6424                                 foreach (Argument a in ea.Arguments){
6425                                         Type argtype = a.Expr.Type;
6426
6427                                         cached_locations [j] = new LocalTemporary (ec, TypeManager.intptr_type /* a.Expr.Type */);
6428                                         a.Expr.Emit (ec);
6429                                         if (argtype == TypeManager.int64_type)
6430                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6431                                         else if (argtype == TypeManager.uint64_type)
6432                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6433
6434                                         ig.Emit (OpCodes.Dup);
6435                                         cached_locations [j].Store (ec);
6436                                         j++;
6437                                 }
6438                                 return;
6439                         }
6440
6441                         foreach (LocalTemporary lt in cached_locations)
6442                                 lt.Emit (ec);
6443                 }
6444
6445                 public new void CacheTemporaries (EmitContext ec)
6446                 {
6447                         cached_locations = new LocalTemporary [ea.Arguments.Count + 1];
6448                 }
6449
6450                 public override void Emit (EmitContext ec)
6451                 {
6452                         int rank = ea.Expr.Type.GetArrayRank ();
6453                         ILGenerator ig = ec.ig;
6454
6455                         LoadArrayAndArguments (ec);
6456
6457                         if (rank == 1)
6458                                 EmitLoadOpcode (ig, type);
6459                         else {
6460                                 MethodInfo method;
6461
6462                                 method = FetchGetMethod ();
6463                                 ig.Emit (OpCodes.Call, method);
6464                         }
6465                 }
6466
6467                 public void EmitAssign (EmitContext ec, Expression source)
6468                 {
6469                         int rank = ea.Expr.Type.GetArrayRank ();
6470                         ILGenerator ig = ec.ig;
6471                         Type t = source.Type;
6472
6473                         LoadArrayAndArguments (ec);
6474
6475                         //
6476                         // The stobj opcode used by value types will need
6477                         // an address on the stack, not really an array/array
6478                         // pair
6479                         //
6480                         if (rank == 1){
6481                                 if (t == TypeManager.enum_type || t == TypeManager.decimal_type ||
6482                                     (t.IsSubclassOf (TypeManager.value_type) && !TypeManager.IsEnumType (t) && !TypeManager.IsBuiltinType (t)))
6483                                         ig.Emit (OpCodes.Ldelema, t);
6484                         }
6485
6486                         source.Emit (ec);
6487
6488                         if (rank == 1)
6489                                 EmitStoreOpcode (ig, t);
6490                         else {
6491                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
6492                                 int arg_count = ea.Arguments.Count;
6493                                 Type [] args = new Type [arg_count + 1];
6494                                 MethodInfo set;
6495
6496                                 for (int i = 0; i < arg_count; i++){
6497                                         //args [i++] = a.Type;
6498                                         args [i] = TypeManager.int32_type;
6499                                 }
6500
6501                                 args [arg_count] = type;
6502
6503                                 set = mb.GetArrayMethod (
6504                                         ea.Expr.Type, "Set",
6505                                         CallingConventions.HasThis |
6506                                         CallingConventions.Standard,
6507                                         TypeManager.void_type, args);
6508
6509                                 ig.Emit (OpCodes.Call, set);
6510                         }
6511                 }
6512
6513                 public void AddressOf (EmitContext ec, AddressOp mode)
6514                 {
6515                         int rank = ea.Expr.Type.GetArrayRank ();
6516                         ILGenerator ig = ec.ig;
6517
6518                         LoadArrayAndArguments (ec);
6519
6520                         if (rank == 1){
6521                                 ig.Emit (OpCodes.Ldelema, type);
6522                         } else {
6523                                 MethodInfo address = FetchAddressMethod ();
6524                                 ig.Emit (OpCodes.Call, address);
6525                         }
6526                 }
6527         }
6528
6529
6530         class Indexers {
6531                 public ArrayList getters, setters;
6532                 static Hashtable map;
6533
6534                 static Indexers ()
6535                 {
6536                         map = new Hashtable ();
6537                 }
6538
6539                 Indexers (MemberInfo [] mi)
6540                 {
6541                         foreach (PropertyInfo property in mi){
6542                                 MethodInfo get, set;
6543
6544                                 get = property.GetGetMethod (true);
6545                                 if (get != null){
6546                                         if (getters == null)
6547                                                 getters = new ArrayList ();
6548
6549                                         getters.Add (get);
6550                                 }
6551
6552                                 set = property.GetSetMethod (true);
6553                                 if (set != null){
6554                                         if (setters == null)
6555                                                 setters = new ArrayList ();
6556                                         setters.Add (set);
6557                                 }
6558                         }
6559                 }
6560
6561                 static private Indexers GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
6562                 {
6563                         Indexers ix = (Indexers) map [lookup_type];
6564
6565                         if (ix != null)
6566                                 return ix;
6567
6568                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
6569
6570                         MemberInfo [] mi = TypeManager.MemberLookup (
6571                                 caller_type, lookup_type, MemberTypes.Property,
6572                                 BindingFlags.Public | BindingFlags.Instance, p_name);
6573
6574                         if (mi == null || mi.Length == 0)
6575                                 return null;
6576
6577                         ix = new Indexers (mi);
6578                         map [lookup_type] = ix;
6579
6580                         return ix;
6581                 }
6582
6583                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
6584                 {
6585                         Indexers ix = (Indexers) map [lookup_type];
6586
6587                         if (ix != null)
6588                                 return ix;
6589
6590                         ix = GetIndexersForTypeOrInterface (caller_type, lookup_type);
6591                         if (ix != null)
6592                                 return ix;
6593
6594                         Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
6595                         if (ifaces != null) {
6596                                 foreach (Type itype in ifaces) {
6597                                         ix = GetIndexersForTypeOrInterface (caller_type, itype);
6598                                         if (ix != null)
6599                                                 return ix;
6600                                 }
6601                         }
6602
6603                         Report.Error (21, loc,
6604                                       "Type '" + TypeManager.MonoBASIC_Name (lookup_type) +
6605                                       "' does not have any indexers defined");
6606                         return null;
6607                 }
6608         }
6609
6610         /// <summary>
6611         ///   Expressions that represent an indexer call.
6612         /// </summary>
6613         public class IndexerAccess : Expression, IAssignMethod {
6614                 //
6615                 // Points to our "data" repository
6616                 //
6617                 MethodInfo get, set;
6618                 Indexers ilist;
6619                 ArrayList set_arguments;
6620                 bool is_base_indexer;
6621
6622                 protected Type indexer_type;
6623                 protected Type current_type;
6624                 protected Expression instance_expr;
6625                 protected ArrayList arguments;
6626
6627                 public IndexerAccess (ElementAccess ea, Location loc)
6628                         : this (ea.Expr, false, loc)
6629                 {
6630                         this.arguments = ea.Arguments;
6631                 }
6632
6633                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
6634                                          Location loc)
6635                 {
6636                         this.instance_expr = instance_expr;
6637                         this.is_base_indexer = is_base_indexer;
6638                         this.eclass = ExprClass.Value;
6639                         this.loc = loc;
6640                 }
6641
6642                 protected virtual bool CommonResolve (EmitContext ec)
6643                 {
6644                         indexer_type = instance_expr.Type;
6645                         current_type = ec.ContainerType;
6646
6647                         return true;
6648                 }
6649
6650                 public override Expression DoResolve (EmitContext ec)
6651                 {
6652                         if (!CommonResolve (ec))
6653                                 return null;
6654
6655                         //
6656                         // Step 1: Query for all 'Item' *properties*.  Notice
6657                         // that the actual methods are pointed from here.
6658                         //
6659                         // This is a group of properties, piles of them.
6660
6661                         if (ilist == null)
6662                                 ilist = Indexers.GetIndexersForType (
6663                                         current_type, indexer_type, loc);
6664
6665                         //
6666                         // Step 2: find the proper match
6667                         //
6668                         if (ilist != null && ilist.getters != null && ilist.getters.Count > 0)
6669                                 get = (MethodInfo) Invocation.OverloadResolve (
6670                                         ec, new MethodGroupExpr (ilist.getters, loc), arguments, loc);
6671
6672                         if (get == null){
6673                                 Error (154, "indexer can not be used in this context, because " +
6674                                        "it lacks a 'get' accessor");
6675                                 return null;
6676                         }
6677
6678                         type = get.ReturnType;
6679                         if (type.IsPointer && !ec.InUnsafe){
6680                                 UnsafeError (loc);
6681                                 return null;
6682                         }
6683
6684                         eclass = ExprClass.IndexerAccess;
6685                         return this;
6686                 }
6687
6688                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6689                 {
6690                         if (!CommonResolve (ec))
6691                                 return null;
6692
6693                         Type right_type = right_side.Type;
6694
6695                         if (ilist == null)
6696                                 ilist = Indexers.GetIndexersForType (
6697                                         current_type, indexer_type, loc);
6698
6699                         if (ilist != null && ilist.setters != null && ilist.setters.Count > 0){
6700                                 set_arguments = (ArrayList) arguments.Clone ();
6701                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
6702
6703                                 set = (MethodInfo) Invocation.OverloadResolve (
6704                                         ec, new MethodGroupExpr (ilist.setters, loc), set_arguments, loc);
6705                         }
6706
6707                         if (set == null){
6708                                 Error (200, "indexer X.this [" + TypeManager.MonoBASIC_Name (right_type) +
6709                                        "] lacks a 'set' accessor");
6710                                 return null;
6711                         }
6712
6713                         type = TypeManager.void_type;
6714                         eclass = ExprClass.IndexerAccess;
6715                         return this;
6716                 }
6717
6718                 public override void Emit (EmitContext ec)
6719                 {
6720                         Invocation.EmitCall (ec, false, false, instance_expr, get, arguments, loc);
6721                 }
6722
6723                 //
6724                 // source is ignored, because we already have a copy of it from the
6725                 // LValue resolution and we have already constructed a pre-cached
6726                 // version of the arguments (ea.set_arguments);
6727                 //
6728                 public void EmitAssign (EmitContext ec, Expression source)
6729                 {
6730                         Invocation.EmitCall (ec, false, false, instance_expr, set, set_arguments, loc);
6731                 }
6732         }
6733
6734         /// <summary>
6735         ///   The base operator for method names
6736         /// </summary>
6737         public class BaseAccess : Expression {
6738                 public string member;
6739
6740                 public BaseAccess (string member, Location l)
6741                 {
6742                         this.member = member;
6743                         loc = l;
6744                 }
6745
6746                 public override Expression DoResolve (EmitContext ec)
6747                 {
6748                         Expression member_lookup;
6749                         Type current_type = ec.ContainerType;
6750                         Type base_type = current_type.BaseType;
6751                         Expression e;
6752
6753                         if (ec.IsStatic){
6754                                 Error (1511, "Keyword MyBase is not allowed in static method");
6755                                 return null;
6756                         }
6757
6758                         if (member == "New")
6759                                 member = ".ctor";
6760
6761                         member_lookup = MemberLookup (ec, current_type, base_type, member,
6762                                                       AllMemberTypes, AllBindingFlags, loc);
6763
6764                         if (member_lookup == null) {
6765                                 Error (30456,
6766                                               TypeManager.MonoBASIC_Name (base_type) + " does not " +
6767                                               "contain a definition for '" + member + "'");
6768                                 return null;
6769                         }
6770
6771                         Expression left;
6772
6773                         if (ec.IsStatic)
6774                                 left = new TypeExpr (base_type, loc);
6775                         else
6776                                 left = ec.This;
6777
6778                         e = MemberAccess.ResolveMemberAccess (ec, member_lookup, left, loc, null);
6779
6780                         if (e is PropertyExpr) {
6781                                 PropertyExpr pe = (PropertyExpr) e;
6782
6783                                 pe.IsBase = true;
6784                         }
6785
6786                         return e;
6787                 }
6788
6789                 public override void Emit (EmitContext ec)
6790                 {
6791                         throw new Exception ("Should never be called");
6792                 }
6793         }
6794
6795         /// <summary>
6796         ///   The base indexer operator
6797         /// </summary>
6798         public class BaseIndexerAccess : IndexerAccess {
6799                 public BaseIndexerAccess (ArrayList args, Location loc)
6800                         : base (null, true, loc)
6801                 {
6802                         arguments = new ArrayList ();
6803                         foreach (Expression tmp in args)
6804                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
6805                 }
6806
6807                 protected override bool CommonResolve (EmitContext ec)
6808                 {
6809                         instance_expr = ec.This;
6810
6811                         current_type = ec.ContainerType.BaseType;
6812                         indexer_type = current_type;
6813
6814                         foreach (Argument a in arguments){
6815                                 if (!a.Resolve (ec, loc))
6816                                         return false;
6817                         }
6818
6819                         return true;
6820                 }
6821         }
6822
6823         /// <summary>
6824         ///   This class exists solely to pass the Type around and to be a dummy
6825         ///   that can be passed to the conversion functions (this is used by
6826         ///   foreach implementation to typecast the object return value from
6827         ///   get_Current into the proper type.  All code has been generated and
6828         ///   we only care about the side effect conversions to be performed
6829         ///
6830         ///   This is also now used as a placeholder where a no-action expression
6831         ///   is needed (the 'New' class).
6832         /// </summary>
6833         public class EmptyExpression : Expression {
6834                 public EmptyExpression ()
6835                 {
6836                         type = TypeManager.object_type;
6837                         eclass = ExprClass.Value;
6838                         loc = Location.Null;
6839                 }
6840
6841                 public EmptyExpression (Type t)
6842                 {
6843                         type = t;
6844                         eclass = ExprClass.Value;
6845                         loc = Location.Null;
6846                 }
6847
6848                 public override Expression DoResolve (EmitContext ec)
6849                 {
6850                         return this;
6851                 }
6852
6853                 public override void Emit (EmitContext ec)
6854                 {
6855                         // nothing, as we only exist to not do anything.
6856                 }
6857
6858                 //
6859                 // This is just because we might want to reuse this bad boy
6860                 // instead of creating gazillions of EmptyExpressions.
6861                 // (CanConvertImplicit uses it)
6862                 //
6863                 public void SetType (Type t)
6864                 {
6865                         type = t;
6866                 }
6867         }
6868
6869         public class UserCast : Expression {
6870                 MethodBase method;
6871                 Expression source;
6872
6873                 public UserCast (MethodInfo method, Expression source, Location l)
6874                 {
6875                         this.method = method;
6876                         this.source = source;
6877                         type = method.ReturnType;
6878                         eclass = ExprClass.Value;
6879                         loc = l;
6880                 }
6881
6882                 public override Expression DoResolve (EmitContext ec)
6883                 {
6884                         //
6885                         // We are born fully resolved
6886                         //
6887                         return this;
6888                 }
6889
6890                 public override void Emit (EmitContext ec)
6891                 {
6892                         ILGenerator ig = ec.ig;
6893
6894                         source.Emit (ec);
6895
6896                         if (method is MethodInfo)
6897                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
6898                         else
6899                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
6900
6901                 }
6902         }
6903
6904         // <summary>
6905         //   This class is used to "construct" the type during a typecast
6906         //   operation.  Since the Type.GetType class in .NET can parse
6907         //   the type specification, we just use this to construct the type
6908         //   one bit at a time.
6909         // </summary>
6910         public class ComposedCast : Expression, ITypeExpression {
6911                 Expression left;
6912                 string dim;
6913
6914                 public ComposedCast (Expression left, string dim, Location l)
6915                 {
6916                         this.left = left;
6917                         this.dim = dim;
6918                         loc = l;
6919                 }
6920
6921                 public Expression DoResolveType (EmitContext ec)
6922                 {
6923                         Type ltype = ec.DeclSpace.ResolveType (left, false, loc);
6924                         if (ltype == null)
6925                                 return null;
6926
6927                         //
6928                         // ltype.Fullname is already fully qualified, so we can skip
6929                         // a lot of probes, and go directly to TypeManager.LookupType
6930                         //
6931                         string cname = ltype.FullName + dim;
6932                         type = TypeManager.LookupTypeDirect (cname);
6933                         if (type == null){
6934                                 //
6935                                 // For arrays of enumerations we are having a problem
6936                                 // with the direct lookup.  Need to investigate.
6937                                 //
6938                                 // For now, fall back to the full lookup in that case.
6939                                 //
6940                                 type = RootContext.LookupType (
6941                                         ec.DeclSpace, cname, false, loc);
6942
6943                                 if (type == null)
6944                                         return null;
6945                         }
6946
6947                         if (!ec.ResolvingTypeTree){
6948                                 //
6949                                 // If the above flag is set, this is being invoked from the ResolveType function.
6950                                 // Upper layers take care of the type validity in this context.
6951                                 //
6952                         if (!ec.InUnsafe && type.IsPointer){
6953                                 UnsafeError (loc);
6954                                 return null;
6955                         }
6956                         }
6957
6958                         eclass = ExprClass.Type;
6959                         return this;
6960                 }
6961
6962                 public override Expression DoResolve (EmitContext ec)
6963                 {
6964                         return DoResolveType (ec);
6965                 }
6966
6967                 public override void Emit (EmitContext ec)
6968                 {
6969                         throw new Exception ("This should never be called");
6970                 }
6971
6972                 public override string ToString ()
6973                 {
6974                         return left + dim;
6975                 }
6976         }
6977
6978         //
6979         // This class is used to represent the address of an array, used
6980         // only by the Fixed statement, this is like the C "&a [0]" construct.
6981         //
6982         public class ArrayPtr : Expression {
6983                 Expression array;
6984
6985                 public ArrayPtr (Expression array, Location l)
6986                 {
6987                         Type array_type = array.Type.GetElementType ();
6988
6989                         this.array = array;
6990
6991                         string array_ptr_type_name = array_type.FullName + "*";
6992
6993                         type = Type.GetType (array_ptr_type_name);
6994                         if (type == null){
6995                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
6996
6997                                 type = mb.GetType (array_ptr_type_name);
6998                         }
6999
7000                         eclass = ExprClass.Value;
7001                         loc = l;
7002                 }
7003
7004                 public override void Emit (EmitContext ec)
7005                 {
7006                         ILGenerator ig = ec.ig;
7007
7008                         array.Emit (ec);
7009                         IntLiteral.EmitInt (ig, 0);
7010                         ig.Emit (OpCodes.Ldelema, array.Type.GetElementType ());
7011                 }
7012
7013                 public override Expression DoResolve (EmitContext ec)
7014                 {
7015                         //
7016                         // We are born fully resolved
7017                         //
7018                         return this;
7019                 }
7020         }
7021
7022         //
7023         // Used by the fixed statement
7024         //
7025         public class StringPtr : Expression {
7026                 LocalBuilder b;
7027
7028                 public StringPtr (LocalBuilder b, Location l)
7029                 {
7030                         this.b = b;
7031                         eclass = ExprClass.Value;
7032                         type = TypeManager.char_ptr_type;
7033                         loc = l;
7034                 }
7035
7036                 public override Expression DoResolve (EmitContext ec)
7037                 {
7038                         // This should never be invoked, we are born in fully
7039                         // initialized state.
7040
7041                         return this;
7042                 }
7043
7044                 public override void Emit (EmitContext ec)
7045                 {
7046                         ILGenerator ig = ec.ig;
7047
7048                         ig.Emit (OpCodes.Ldloc, b);
7049                         ig.Emit (OpCodes.Conv_I);
7050                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
7051                         ig.Emit (OpCodes.Add);
7052                 }
7053         }
7054
7055         //
7056         // Implements the 'stackalloc' keyword
7057         //
7058         public class StackAlloc : Expression {
7059                 Type otype;
7060                 Expression t;
7061                 Expression count;
7062
7063                 public StackAlloc (Expression type, Expression count, Location l)
7064                 {
7065                         t = type;
7066                         this.count = count;
7067                         loc = l;
7068                 }
7069
7070                 public override Expression DoResolve (EmitContext ec)
7071                 {
7072                         count = count.Resolve (ec);
7073                         if (count == null)
7074                                 return null;
7075
7076                         if (count.Type != TypeManager.int32_type){
7077                                 count = ConvertImplicitRequired (ec, count, TypeManager.int32_type, loc);
7078                                 if (count == null)
7079                                         return null;
7080                         }
7081
7082                         if (ec.InCatch || ec.InFinally){
7083                                 Error (255,
7084                                               "stackalloc can not be used in a catch or finally block");
7085                                 return null;
7086                         }
7087
7088                         otype = ec.DeclSpace.ResolveType (t, false, loc);
7089
7090                         if (otype == null)
7091                                 return null;
7092
7093                         if (!TypeManager.VerifyUnManaged (otype, loc))
7094                                 return null;
7095
7096                         string ptr_name = otype.FullName + "*";
7097                         type = Type.GetType (ptr_name);
7098                         if (type == null){
7099                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
7100
7101                                 type = mb.GetType (ptr_name);
7102                         }
7103                         eclass = ExprClass.Value;
7104
7105                         return this;
7106                 }
7107
7108                 public override void Emit (EmitContext ec)
7109                 {
7110                         int size = GetTypeSize (otype);
7111                         ILGenerator ig = ec.ig;
7112
7113                         if (size == 0)
7114                                 ig.Emit (OpCodes.Sizeof, otype);
7115                         else
7116                                 IntConstant.EmitInt (ig, size);
7117                         count.Emit (ec);
7118                         ig.Emit (OpCodes.Mul);
7119                         ig.Emit (OpCodes.Localloc);
7120                 }
7121         }
7122 }