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\r
1190                 {
1191                         get {
1192                                 return runtime_cast;
1193                         }
1194                         set{
1195                                 runtime_cast = value;
1196                         }
1197                 }
1198
1199                 /// <summary>
1200                 ///   Attempts to do a compile-time folding of a constant cast.
1201                 /// </summary>
1202                 Expression TryReduce (EmitContext ec, Type target_type)
1203                 {
1204                         if (expr is ByteConstant){
1205                                 byte v = ((ByteConstant) expr).Value;
1206
1207                                 if (target_type == TypeManager.sbyte_type)
1208                                         return new SByteConstant ((sbyte) v);
1209                                 if (target_type == TypeManager.short_type)
1210                                         return new ShortConstant ((short) v);
1211                                 if (target_type == TypeManager.ushort_type)
1212                                         return new UShortConstant ((ushort) v);
1213                                 if (target_type == TypeManager.int32_type)
1214                                         return new IntConstant ((int) v);
1215                                 if (target_type == TypeManager.uint32_type)
1216                                         return new UIntConstant ((uint) v);
1217                                 if (target_type == TypeManager.int64_type)
1218                                         return new LongConstant ((long) v);
1219                                 if (target_type == TypeManager.uint64_type)
1220                                         return new ULongConstant ((ulong) v);
1221                                 if (target_type == TypeManager.float_type)
1222                                         return new FloatConstant ((float) v);
1223                                 if (target_type == TypeManager.double_type)
1224                                         return new DoubleConstant ((double) v);
1225                                 if (target_type == TypeManager.char_type)
1226                                         return new CharConstant ((char) v);
1227                                 if (target_type == TypeManager.decimal_type)
1228                                         return new DecimalConstant ((decimal) v);
1229                         }
1230                         if (expr is SByteConstant){
1231                                 sbyte v = ((SByteConstant) expr).Value;
1232
1233                                 if (target_type == TypeManager.byte_type)
1234                                         return new ByteConstant ((byte) v);
1235                                 if (target_type == TypeManager.short_type)
1236                                         return new ShortConstant ((short) v);
1237                                 if (target_type == TypeManager.ushort_type)
1238                                         return new UShortConstant ((ushort) v);
1239                                 if (target_type == TypeManager.int32_type)
1240                                         return new IntConstant ((int) v);
1241                                 if (target_type == TypeManager.uint32_type)
1242                                         return new UIntConstant ((uint) v);
1243                                 if (target_type == TypeManager.int64_type)
1244                                         return new LongConstant ((long) v);
1245                                 if (target_type == TypeManager.uint64_type)
1246                                         return new ULongConstant ((ulong) v);
1247                                 if (target_type == TypeManager.float_type)
1248                                         return new FloatConstant ((float) v);
1249                                 if (target_type == TypeManager.double_type)
1250                                         return new DoubleConstant ((double) v);
1251                                 if (target_type == TypeManager.char_type)
1252                                         return new CharConstant ((char) v);
1253                                 if (target_type == TypeManager.decimal_type)
1254                                         return new DecimalConstant ((decimal) v);
1255                         }
1256                         if (expr is ShortConstant){
1257                                 short v = ((ShortConstant) expr).Value;
1258
1259                                 if (target_type == TypeManager.byte_type)
1260                                         return new ByteConstant ((byte) v);
1261                                 if (target_type == TypeManager.sbyte_type)
1262                                         return new SByteConstant ((sbyte) v);
1263                                 if (target_type == TypeManager.ushort_type)
1264                                         return new UShortConstant ((ushort) v);
1265                                 if (target_type == TypeManager.int32_type)
1266                                         return new IntConstant ((int) v);
1267                                 if (target_type == TypeManager.uint32_type)
1268                                         return new UIntConstant ((uint) v);
1269                                 if (target_type == TypeManager.int64_type)
1270                                         return new LongConstant ((long) v);
1271                                 if (target_type == TypeManager.uint64_type)
1272                                         return new ULongConstant ((ulong) v);
1273                                 if (target_type == TypeManager.float_type)
1274                                         return new FloatConstant ((float) v);
1275                                 if (target_type == TypeManager.double_type)
1276                                         return new DoubleConstant ((double) v);
1277                                 if (target_type == TypeManager.char_type)
1278                                         return new CharConstant ((char) v);
1279                                 if (target_type == TypeManager.decimal_type)
1280                                         return new DecimalConstant ((decimal) v);
1281                         }
1282                         if (expr is UShortConstant){
1283                                 ushort v = ((UShortConstant) expr).Value;
1284
1285                                 if (target_type == TypeManager.byte_type)
1286                                         return new ByteConstant ((byte) v);
1287                                 if (target_type == TypeManager.sbyte_type)
1288                                         return new SByteConstant ((sbyte) v);
1289                                 if (target_type == TypeManager.short_type)
1290                                         return new ShortConstant ((short) v);
1291                                 if (target_type == TypeManager.int32_type)
1292                                         return new IntConstant ((int) v);
1293                                 if (target_type == TypeManager.uint32_type)
1294                                         return new UIntConstant ((uint) v);
1295                                 if (target_type == TypeManager.int64_type)
1296                                         return new LongConstant ((long) v);
1297                                 if (target_type == TypeManager.uint64_type)
1298                                         return new ULongConstant ((ulong) v);
1299                                 if (target_type == TypeManager.float_type)
1300                                         return new FloatConstant ((float) v);
1301                                 if (target_type == TypeManager.double_type)
1302                                         return new DoubleConstant ((double) v);
1303                                 if (target_type == TypeManager.char_type)
1304                                         return new CharConstant ((char) v);
1305                                 if (target_type == TypeManager.decimal_type)
1306                                         return new DecimalConstant ((decimal) v);
1307                         }
1308                         if (expr is IntConstant){
1309                                 int v = ((IntConstant) expr).Value;
1310
1311                                 if (target_type == TypeManager.byte_type)
1312                                         return new ByteConstant ((byte) v);
1313                                 if (target_type == TypeManager.sbyte_type)
1314                                         return new SByteConstant ((sbyte) v);
1315                                 if (target_type == TypeManager.short_type)
1316                                         return new ShortConstant ((short) v);
1317                                 if (target_type == TypeManager.ushort_type)
1318                                         return new UShortConstant ((ushort) v);
1319                                 if (target_type == TypeManager.uint32_type)
1320                                         return new UIntConstant ((uint) v);
1321                                 if (target_type == TypeManager.int64_type)
1322                                         return new LongConstant ((long) v);
1323                                 if (target_type == TypeManager.uint64_type)
1324                                         return new ULongConstant ((ulong) v);
1325                                 if (target_type == TypeManager.float_type)
1326                                         return new FloatConstant ((float) v);
1327                                 if (target_type == TypeManager.double_type)
1328                                         return new DoubleConstant ((double) v);
1329                                 if (target_type == TypeManager.char_type)
1330                                         return new CharConstant ((char) v);
1331                                 if (target_type == TypeManager.decimal_type)
1332                                         return new DecimalConstant ((decimal) v);
1333                         }
1334                         if (expr is UIntConstant){
1335                                 uint v = ((UIntConstant) expr).Value;
1336
1337                                 if (target_type == TypeManager.byte_type)
1338                                         return new ByteConstant ((byte) v);
1339                                 if (target_type == TypeManager.sbyte_type)
1340                                         return new SByteConstant ((sbyte) v);
1341                                 if (target_type == TypeManager.short_type)
1342                                         return new ShortConstant ((short) v);
1343                                 if (target_type == TypeManager.ushort_type)
1344                                         return new UShortConstant ((ushort) v);
1345                                 if (target_type == TypeManager.int32_type)
1346                                         return new IntConstant ((int) v);
1347                                 if (target_type == TypeManager.int64_type)
1348                                         return new LongConstant ((long) v);
1349                                 if (target_type == TypeManager.uint64_type)
1350                                         return new ULongConstant ((ulong) v);
1351                                 if (target_type == TypeManager.float_type)
1352                                         return new FloatConstant ((float) v);
1353                                 if (target_type == TypeManager.double_type)
1354                                         return new DoubleConstant ((double) v);
1355                                 if (target_type == TypeManager.char_type)
1356                                         return new CharConstant ((char) v);
1357                                 if (target_type == TypeManager.decimal_type)
1358                                         return new DecimalConstant ((decimal) v);
1359                         }
1360                         if (expr is LongConstant){
1361                                 long v = ((LongConstant) expr).Value;
1362
1363                                 if (target_type == TypeManager.byte_type)
1364                                         return new ByteConstant ((byte) v);
1365                                 if (target_type == TypeManager.sbyte_type)
1366                                         return new SByteConstant ((sbyte) v);
1367                                 if (target_type == TypeManager.short_type)
1368                                         return new ShortConstant ((short) v);
1369                                 if (target_type == TypeManager.ushort_type)
1370                                         return new UShortConstant ((ushort) v);
1371                                 if (target_type == TypeManager.int32_type)
1372                                         return new IntConstant ((int) v);
1373                                 if (target_type == TypeManager.uint32_type)
1374                                         return new UIntConstant ((uint) v);
1375                                 if (target_type == TypeManager.uint64_type)
1376                                         return new ULongConstant ((ulong) v);
1377                                 if (target_type == TypeManager.float_type)
1378                                         return new FloatConstant ((float) v);
1379                                 if (target_type == TypeManager.double_type)
1380                                         return new DoubleConstant ((double) v);
1381                                 if (target_type == TypeManager.char_type)
1382                                         return new CharConstant ((char) v);
1383                                 if (target_type == TypeManager.decimal_type)
1384                                         return new DecimalConstant ((decimal) v);
1385                         }
1386                         if (expr is ULongConstant){
1387                                 ulong v = ((ULongConstant) expr).Value;
1388
1389                                 if (target_type == TypeManager.byte_type)
1390                                         return new ByteConstant ((byte) v);
1391                                 if (target_type == TypeManager.sbyte_type)
1392                                         return new SByteConstant ((sbyte) v);
1393                                 if (target_type == TypeManager.short_type)
1394                                         return new ShortConstant ((short) v);
1395                                 if (target_type == TypeManager.ushort_type)
1396                                         return new UShortConstant ((ushort) v);
1397                                 if (target_type == TypeManager.int32_type)
1398                                         return new IntConstant ((int) v);
1399                                 if (target_type == TypeManager.uint32_type)
1400                                         return new UIntConstant ((uint) v);
1401                                 if (target_type == TypeManager.int64_type)
1402                                         return new LongConstant ((long) v);
1403                                 if (target_type == TypeManager.float_type)
1404                                         return new FloatConstant ((float) v);
1405                                 if (target_type == TypeManager.double_type)
1406                                         return new DoubleConstant ((double) v);
1407                                 if (target_type == TypeManager.char_type)
1408                                         return new CharConstant ((char) v);
1409                                 if (target_type == TypeManager.decimal_type)
1410                                         return new DecimalConstant ((decimal) v);
1411                         }
1412                         if (expr is FloatConstant){
1413                                 float v = ((FloatConstant) expr).Value;
1414
1415                                 if (target_type == TypeManager.byte_type)
1416                                         return new ByteConstant ((byte) v);
1417                                 if (target_type == TypeManager.sbyte_type)
1418                                         return new SByteConstant ((sbyte) v);
1419                                 if (target_type == TypeManager.short_type)
1420                                         return new ShortConstant ((short) v);
1421                                 if (target_type == TypeManager.ushort_type)
1422                                         return new UShortConstant ((ushort) v);
1423                                 if (target_type == TypeManager.int32_type)
1424                                         return new IntConstant ((int) v);
1425                                 if (target_type == TypeManager.uint32_type)
1426                                         return new UIntConstant ((uint) v);
1427                                 if (target_type == TypeManager.int64_type)
1428                                         return new LongConstant ((long) v);
1429                                 if (target_type == TypeManager.uint64_type)
1430                                         return new ULongConstant ((ulong) v);
1431                                 if (target_type == TypeManager.double_type)
1432                                         return new DoubleConstant ((double) v);
1433                                 if (target_type == TypeManager.char_type)
1434                                         return new CharConstant ((char) v);
1435                                 if (target_type == TypeManager.decimal_type)
1436                                         return new DecimalConstant ((decimal) v);
1437                         }
1438                         if (expr is DoubleConstant){
1439                                 double v = ((DoubleConstant) expr).Value;
1440
1441                                 if (target_type == TypeManager.byte_type)
1442                                         return new ByteConstant ((byte) v);
1443                                 if (target_type == TypeManager.sbyte_type)
1444                                         return new SByteConstant ((sbyte) v);
1445                                 if (target_type == TypeManager.short_type)
1446                                         return new ShortConstant ((short) v);
1447                                 if (target_type == TypeManager.ushort_type)
1448                                         return new UShortConstant ((ushort) v);
1449                                 if (target_type == TypeManager.int32_type)
1450                                         return new IntConstant ((int) v);
1451                                 if (target_type == TypeManager.uint32_type)
1452                                         return new UIntConstant ((uint) v);
1453                                 if (target_type == TypeManager.int64_type)
1454                                         return new LongConstant ((long) v);
1455                                 if (target_type == TypeManager.uint64_type)
1456                                         return new ULongConstant ((ulong) v);
1457                                 if (target_type == TypeManager.float_type)
1458                                         return new FloatConstant ((float) v);
1459                                 if (target_type == TypeManager.char_type)
1460                                         return new CharConstant ((char) v);
1461                                 if (target_type == TypeManager.decimal_type)
1462                                         return new DecimalConstant ((decimal) v);
1463                         }
1464
1465                         return null;
1466                 }
1467
1468                 public override Expression DoResolve (EmitContext ec)
1469                 {
1470                         expr = expr.Resolve (ec);
1471                         if (expr == null)
1472                                 return null;
1473
1474                         int errors = Report.Errors;
1475
1476                         type = ec.DeclSpace.ResolveType (target_type, false, Location);
1477
1478                         if (type == null)
1479                                 return null;
1480
1481                         eclass = ExprClass.Value;
1482
1483                         if (expr is Constant){
1484                                 Expression e = TryReduce (ec, type);
1485
1486                                 if (e != null)
1487                                         return e;
1488                         }
1489
1490                         expr = ConvertExplicit (ec, expr, type, runtime_cast, loc);
1491                         return expr;
1492                 }
1493
1494                 public override void Emit (EmitContext ec)
1495                 {
1496                         //
1497                         // This one will never happen
1498                         //
1499                         throw new Exception ("Should not happen");
1500                 }
1501         }
1502
1503         /// <summary>
1504         ///   Binary operators
1505         /// </summary>
1506         public class Binary : Expression {
1507                 public enum Operator : byte {
1508                         Multiply, Division, Modulus,
1509                         Addition, Subtraction,
1510                         LeftShift, RightShift,
1511                         LessThan, GreaterThan, LessThanOrEqual, GreaterThanOrEqual,
1512                         Equality, Inequality,
1513                         BitwiseAnd,
1514                         ExclusiveOr,
1515                         BitwiseOr,
1516                         LogicalAnd,
1517                         LogicalOr,
1518                         TOP
1519                 }
1520
1521                 Operator oper;
1522                 Expression left, right;
1523
1524                 //
1525                 // After resolution, method might contain the operator overload
1526                 // method.
1527                 //
1528                 protected MethodBase method;
1529                 ArrayList  Arguments;
1530
1531                 bool DelegateOperation;
1532
1533                 // This must be kept in sync with Operator!!!
1534                 static string [] oper_names;
1535
1536                 static Binary ()
1537                 {
1538                         oper_names = new string [(int) Operator.TOP];
1539
1540                         oper_names [(int) Operator.Multiply] = "op_Multiply";
1541                         oper_names [(int) Operator.Division] = "op_Division";
1542                         oper_names [(int) Operator.Modulus] = "op_Modulus";
1543                         oper_names [(int) Operator.Addition] = "op_Addition";
1544                         oper_names [(int) Operator.Subtraction] = "op_Subtraction";
1545                         oper_names [(int) Operator.LeftShift] = "op_LeftShift";
1546                         oper_names [(int) Operator.RightShift] = "op_RightShift";
1547                         oper_names [(int) Operator.LessThan] = "op_LessThan";
1548                         oper_names [(int) Operator.GreaterThan] = "op_GreaterThan";
1549                         oper_names [(int) Operator.LessThanOrEqual] = "op_LessThanOrEqual";
1550                         oper_names [(int) Operator.GreaterThanOrEqual] = "op_GreaterThanOrEqual";
1551                         oper_names [(int) Operator.Equality] = "op_Equality";
1552                         oper_names [(int) Operator.Inequality] = "op_Inequality";
1553                         oper_names [(int) Operator.BitwiseAnd] = "op_BitwiseAnd";
1554                         oper_names [(int) Operator.BitwiseOr] = "op_BitwiseOr";
1555                         oper_names [(int) Operator.ExclusiveOr] = "op_ExclusiveOr";
1556                         oper_names [(int) Operator.LogicalOr] = "op_LogicalOr";
1557                         oper_names [(int) Operator.LogicalAnd] = "op_LogicalAnd";
1558                 }
1559
1560                 public Binary (Operator oper, Expression left, Expression right, Location loc)
1561                 {
1562                         this.oper = oper;
1563                         this.left = left;
1564                         this.right = right;
1565                         this.loc = loc;
1566                 }
1567
1568                 public Operator Oper {
1569                         get {
1570                                 return oper;
1571                         }
1572                         set {
1573                                 oper = value;
1574                         }
1575                 }
1576
1577                 public Expression Left {
1578                         get {
1579                                 return left;
1580                         }
1581                         set {
1582                                 left = value;
1583                         }
1584                 }
1585
1586                 public Expression Right {
1587                         get {
1588                                 return right;
1589                         }
1590                         set {
1591                                 right = value;
1592                         }
1593                 }
1594
1595
1596                 /// <summary>
1597                 ///   Returns a stringified representation of the Operator
1598                 /// </summary>
1599                 static string OperName (Operator oper)
1600                 {
1601                         switch (oper){
1602                         case Operator.Multiply:
1603                                 return "*";
1604                         case Operator.Division:
1605                                 return "/";
1606                         case Operator.Modulus:
1607                                 return "%";
1608                         case Operator.Addition:
1609                                 return "+";
1610                         case Operator.Subtraction:
1611                                 return "-";
1612                         case Operator.LeftShift:
1613                                 return "<<";
1614                         case Operator.RightShift:
1615                                 return ">>";
1616                         case Operator.LessThan:
1617                                 return "<";
1618                         case Operator.GreaterThan:
1619                                 return ">";
1620                         case Operator.LessThanOrEqual:
1621                                 return "<=";
1622                         case Operator.GreaterThanOrEqual:
1623                                 return ">=";
1624                         case Operator.Equality:
1625                                 return "==";
1626                         case Operator.Inequality:
1627                                 return "!=";
1628                         case Operator.BitwiseAnd:
1629                                 return "&";
1630                         case Operator.BitwiseOr:
1631                                 return "|";
1632                         case Operator.ExclusiveOr:
1633                                 return "^";
1634                         case Operator.LogicalOr:
1635                                 return "||";
1636                         case Operator.LogicalAnd:
1637                                 return "&&";
1638                         }
1639
1640                         return oper.ToString ();
1641                 }
1642
1643                 public override string ToString ()
1644                 {
1645                         return "operator " + OperName (oper) + "(" + left.ToString () + ", " +
1646                                 right.ToString () + ")";
1647                 }
1648
1649                 Expression ForceConversion (EmitContext ec, Expression expr, Type target_type)
1650                 {
1651                         if (expr.Type == target_type)
1652                                 return expr;
1653
1654                         return ConvertImplicit (ec, expr, target_type, Location.Null);
1655                 }
1656
1657                 public static void Error_OperatorAmbiguous (Location loc, Operator oper, Type l, Type r)
1658                 {
1659                         Report.Error (
1660                                 34, loc, "Operator '" + OperName (oper)
1661                                 + "' is ambiguous on operands of type '"
1662                                 + TypeManager.MonoBASIC_Name (l) + "' "
1663                                 + "and '" + TypeManager.MonoBASIC_Name (r)
1664                                 + "'");
1665                 }
1666
1667                 //
1668                 // Note that handling the case l == Decimal || r == Decimal
1669                 // is taken care of by the Step 1 Operator Overload resolution.
1670                 //
1671                 bool DoNumericPromotions (EmitContext ec, Type l, Type r)
1672                 {
1673                         if (l == TypeManager.double_type || r == TypeManager.double_type){
1674                                 //
1675                                 // If either operand is of type double, the other operand is
1676                                 // conveted to type double.
1677                                 //
1678                                 if (r != TypeManager.double_type)
1679                                         right = ConvertImplicit (ec, right, TypeManager.double_type, loc);
1680                                 if (l != TypeManager.double_type)
1681                                         left = ConvertImplicit (ec, left, TypeManager.double_type, loc);
1682
1683                                 type = TypeManager.double_type;
1684                         } else if (l == TypeManager.float_type || r == TypeManager.float_type){
1685                                 //
1686                                 // if either operand is of type float, the other operand is
1687                                 // converted to type float.
1688                                 //
1689                                 if (r != TypeManager.double_type)
1690                                         right = ConvertImplicit (ec, right, TypeManager.float_type, loc);
1691                                 if (l != TypeManager.double_type)
1692                                         left = ConvertImplicit (ec, left, TypeManager.float_type, loc);
1693                                 type = TypeManager.float_type;
1694                         } else if (l == TypeManager.uint64_type || r == TypeManager.uint64_type){
1695                                 Expression e;
1696                                 Type other;
1697                                 //
1698                                 // If either operand is of type ulong, the other operand is
1699                                 // converted to type ulong.  or an error ocurrs if the other
1700                                 // operand is of type sbyte, short, int or long
1701                                 //
1702                                 if (l == TypeManager.uint64_type){
1703                                         if (r != TypeManager.uint64_type){
1704                                                 if (right is IntConstant){
1705                                                         IntConstant ic = (IntConstant) right;
1706
1707                                                         e = TryImplicitIntConversion (l, ic);
1708                                                         if (e != null)
1709                                                                 right = e;
1710                                                 } else if (right is LongConstant){
1711                                                         long ll = ((LongConstant) right).Value;
1712
1713                                                         if (ll > 0)
1714                                                                 right = new ULongConstant ((ulong) ll);
1715                                                 } else {
1716                                                         e = ImplicitNumericConversion (ec, right, l, loc);
1717                                                         if (e != null)
1718                                                                 right = e;
1719                                                 }
1720                                         }
1721                                         other = right.Type;
1722                                 } else {
1723                                         if (left is IntConstant){
1724                                                 e = TryImplicitIntConversion (r, (IntConstant) left);
1725                                                 if (e != null)
1726                                                         left = e;
1727                                         } else if (left is LongConstant){
1728                                                 long ll = ((LongConstant) left).Value;
1729
1730                                                 if (ll > 0)
1731                                                         left = new ULongConstant ((ulong) ll);
1732                                         } else {
1733                                                 e = ImplicitNumericConversion (ec, left, r, loc);
1734                                                 if (e != null)
1735                                                         left = e;
1736                                         }
1737                                         other = left.Type;
1738                                 }
1739
1740                                 if ((other == TypeManager.sbyte_type) ||
1741                                     (other == TypeManager.short_type) ||
1742                                     (other == TypeManager.int32_type) ||
1743                                     (other == TypeManager.int64_type))
1744                                         Error_OperatorAmbiguous (loc, oper, l, r);
1745                                 type = TypeManager.uint64_type;
1746                         } else if (l == TypeManager.int64_type || r == TypeManager.int64_type){
1747                                 //
1748                                 // If either operand is of type long, the other operand is converted
1749                                 // to type long.
1750                                 //
1751                                 if (l != TypeManager.int64_type)
1752                                         left = ConvertImplicit (ec, left, TypeManager.int64_type, loc);
1753                                 if (r != TypeManager.int64_type)
1754                                         right = ConvertImplicit (ec, right, TypeManager.int64_type, loc);
1755
1756                                 type = TypeManager.int64_type;
1757                         } else if (l == TypeManager.uint32_type || r == TypeManager.uint32_type){
1758                                 //
1759                                 // If either operand is of type uint, and the other
1760                                 // operand is of type sbyte, short or int, othe operands are
1761                                 // converted to type long.
1762                                 //
1763                                 Type other = null;
1764
1765                                 if (l == TypeManager.uint32_type){
1766                                         if (right is IntConstant){
1767                                                 IntConstant ic = (IntConstant) right;
1768                                                 int val = ic.Value;
1769
1770                                                 if (val >= 0)
1771                                                         right = new UIntConstant ((uint) val);
1772
1773                                                 type = l;
1774                                                 return true;
1775                                         }
1776                                         other = r;
1777                                 }
1778                                 else if (r == TypeManager.uint32_type){
1779                                         if (left is IntConstant){
1780                                                 IntConstant ic = (IntConstant) left;
1781                                                 int val = ic.Value;
1782
1783                                                 if (val >= 0)
1784                                                         left = new UIntConstant ((uint) val);
1785
1786                                                 type = r;
1787                                                 return true;
1788                                         }
1789
1790                                         other = l;
1791                                 }
1792
1793                                 if ((other == TypeManager.sbyte_type) ||
1794                                     (other == TypeManager.short_type) ||
1795                                     (other == TypeManager.int32_type)){
1796                                         left = ForceConversion (ec, left, TypeManager.int64_type);
1797                                         right = ForceConversion (ec, right, TypeManager.int64_type);
1798                                         type = TypeManager.int64_type;
1799                                 } else {
1800                                         //
1801                                         // if either operand is of type uint, the other
1802                                         // operand is converd to type uint
1803                                         //
1804                                         left = ForceConversion (ec, left, TypeManager.uint32_type);
1805                                         right = ForceConversion (ec, right, TypeManager.uint32_type);
1806                                         type = TypeManager.uint32_type;
1807                                 }
1808                         } else if (l == TypeManager.decimal_type || r == TypeManager.decimal_type){
1809                                 if (l != TypeManager.decimal_type)
1810                                         left = ConvertImplicit (ec, left, TypeManager.decimal_type, loc);
1811
1812                                 if (r != TypeManager.decimal_type)
1813                                         right = ConvertImplicit (ec, right, TypeManager.decimal_type, loc);
1814                                 type = TypeManager.decimal_type;
1815                         } else {
1816                                 left = ForceConversion (ec, left, TypeManager.int32_type);
1817                                 right = ForceConversion (ec, right, TypeManager.int32_type);
1818
1819                                 type = TypeManager.int32_type;
1820                         }
1821
1822                         return (left != null) && (right != null);
1823                 }
1824
1825                 static public void Error_OperatorCannotBeApplied (Location loc, string name, Type l, Type r)
1826                 {
1827                         Report.Error (19, loc,
1828                                "Operator " + name + " cannot be applied to operands of type '" +
1829                                TypeManager.MonoBASIC_Name (l) + "' and '" +
1830                                TypeManager.MonoBASIC_Name (r) + "'");
1831                 }
1832
1833                 void Error_OperatorCannotBeApplied ()
1834                 {
1835                         Error_OperatorCannotBeApplied (loc, OperName (oper), left.Type, right.Type);
1836                 }
1837
1838                 static bool is_32_or_64 (Type t)
1839                 {
1840                         return (t == TypeManager.int32_type || t == TypeManager.uint32_type ||
1841                                 t == TypeManager.int64_type || t == TypeManager.uint64_type);
1842                 }
1843
1844                 static bool is_unsigned (Type t)
1845                 {
1846                         return (t == TypeManager.uint32_type || t == TypeManager.uint64_type ||
1847                                 t == TypeManager.short_type || t == TypeManager.byte_type);
1848                 }
1849
1850                 Expression CheckShiftArguments (EmitContext ec)
1851                 {
1852                         Expression e;
1853                         Type l = left.Type;
1854                         Type r = right.Type;
1855
1856                         e = ForceConversion (ec, right, TypeManager.int32_type);
1857                         if (e == null){
1858                                 Error_OperatorCannotBeApplied ();
1859                                 return null;
1860                         }
1861                         right = e;
1862
1863                         if (((e = ConvertImplicit (ec, left, TypeManager.int32_type, loc)) != null) ||
1864                             ((e = ConvertImplicit (ec, left, TypeManager.uint32_type, loc)) != null) ||
1865                             ((e = ConvertImplicit (ec, left, TypeManager.int64_type, loc)) != null) ||
1866                             ((e = ConvertImplicit (ec, left, TypeManager.uint64_type, loc)) != null)){
1867                                 left = e;
1868                                 type = e.Type;
1869
1870                                 return this;
1871                         }
1872                         Error_OperatorCannotBeApplied ();
1873                         return null;
1874                 }
1875
1876                 Expression ResolveOperator (EmitContext ec)
1877                 {
1878                         Type l = left.Type;
1879                         Type r = right.Type;
1880
1881                         bool overload_failed = false;
1882
1883                         //
1884                         // Step 1: Perform Operator Overload location
1885                         //
1886                         Expression left_expr, right_expr;
1887
1888                         string op = oper_names [(int) oper];
1889
1890                         MethodGroupExpr union;
1891                         left_expr = MemberLookup (ec, l, op, MemberTypes.Method, AllBindingFlags, loc);
1892                         if (r != l){
1893                                 right_expr = MemberLookup (
1894                                         ec, r, op, MemberTypes.Method, AllBindingFlags, loc);
1895                                 union = Invocation.MakeUnionSet (left_expr, right_expr, loc);
1896                         } else
1897                                 union = (MethodGroupExpr) left_expr;
1898
1899                         if (union != null) {
1900                                 Arguments = new ArrayList ();
1901                                 Arguments.Add (new Argument (left, Argument.AType.Expression));
1902                                 Arguments.Add (new Argument (right, Argument.AType.Expression));
1903
1904                                 method = Invocation.OverloadResolve (ec, union, Arguments, Location.Null);
1905                                 if (method != null) {
1906                                         MethodInfo mi = (MethodInfo) method;
1907
1908                                         type = mi.ReturnType;
1909                                         return this;
1910                                 } else {
1911                                         overload_failed = true;
1912                                 }
1913                         }
1914
1915                         //
1916                         // Step 2: Default operations on CLI native types.
1917                         //
1918
1919                         //
1920                         // Step 0: String concatenation (because overloading will get this wrong)
1921                         //
1922                         if (oper == Operator.Addition){
1923                                 //
1924                                 // If any of the arguments is a string, cast to string
1925                                 //
1926
1927                                 if (l == TypeManager.string_type){
1928
1929                                         if (r == TypeManager.void_type) {
1930                                                 Error_OperatorCannotBeApplied ();
1931                                                 return null;
1932                                         }
1933
1934                                         if (r == TypeManager.string_type){
1935                                                 if (left is Constant && right is Constant){
1936                                                         StringConstant ls = (StringConstant) left;
1937                                                         StringConstant rs = (StringConstant) right;
1938
1939                                                         return new StringConstant (
1940                                                                 ls.Value + rs.Value);
1941                                                 }
1942
1943                                                 // string + string
1944                                                 method = TypeManager.string_concat_string_string;
1945                                         } else {
1946                                                 // string + object
1947                                                 method = TypeManager.string_concat_object_object;
1948                                                 right = ConvertImplicit (ec, right,
1949                                                                          TypeManager.object_type, loc);
1950                                                 if (right == null){
1951                                                         Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
1952                                                         return null;
1953                                                 }
1954                                         }
1955                                         type = TypeManager.string_type;
1956
1957                                         Arguments = new ArrayList ();
1958                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
1959                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
1960
1961                                         return this;
1962
1963                                 } else if (r == TypeManager.string_type){
1964                                         // object + string
1965
1966                                         if (l == TypeManager.void_type) {
1967                                                 Error_OperatorCannotBeApplied ();
1968                                                 return null;
1969                                         }
1970
1971                                         method = TypeManager.string_concat_object_object;
1972                                         left = ConvertImplicit (ec, left, TypeManager.object_type, loc);
1973                                         if (left == null){
1974                                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
1975                                                 return null;
1976                                         }
1977                                         Arguments = new ArrayList ();
1978                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
1979                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
1980
1981                                         type = TypeManager.string_type;
1982
1983                                         return this;
1984                                 }
1985
1986                                 //
1987                                 // Transform a + ( - b) into a - b
1988                                 //
1989                                 if (right is Unary){
1990                                         Unary right_unary = (Unary) right;
1991
1992                                         if (right_unary.Oper == Unary.Operator.UnaryNegation){
1993                                                 oper = Operator.Subtraction;
1994                                                 right = right_unary.Expr;
1995                                                 r = right.Type;
1996                                         }
1997                                 }
1998                         }
1999
2000                         if (oper == Operator.Equality || oper == Operator.Inequality){
2001                                 if (l == TypeManager.bool_type || r == TypeManager.bool_type){
2002                                         if (r != TypeManager.bool_type || l != TypeManager.bool_type){
2003                                                 Error_OperatorCannotBeApplied ();
2004                                                 return null;
2005                                         }
2006
2007                                         type = TypeManager.bool_type;
2008                                         return this;
2009                                 }
2010
2011                                 //
2012                                 // operator != (object a, object b)
2013                                 // operator == (object a, object b)
2014                                 //
2015                                 // For this to be used, both arguments have to be reference-types.
2016                                 // Read the rationale on the spec (14.9.6)
2017                                 //
2018                                 // Also, if at compile time we know that the classes do not inherit
2019                                 // one from the other, then we catch the error there.
2020                                 //
2021                                 if (!(l.IsValueType || r.IsValueType)){
2022                                         type = TypeManager.bool_type;
2023
2024                                         if (l == r)
2025                                                 return this;
2026
2027                                         if (l.IsSubclassOf (r) || r.IsSubclassOf (l))
2028                                                 return this;
2029
2030                                         //
2031                                         // Also, a standard conversion must exist from either one
2032                                         //
2033                                         if (!(StandardConversionExists (left, r) ||
2034                                               StandardConversionExists (right, l))){
2035                                                 Error_OperatorCannotBeApplied ();
2036                                                 return null;
2037                                         }
2038                                         //
2039                                         // We are going to have to convert to an object to compare
2040                                         //
2041                                         if (l != TypeManager.object_type)
2042                                                 left = new EmptyCast (left, TypeManager.object_type);
2043                                         if (r != TypeManager.object_type)
2044                                                 right = new EmptyCast (right, TypeManager.object_type);
2045
2046                                         //
2047                                         // FIXME: CSC here catches errors cs254 and cs252
2048                                         //
2049                                         return this;
2050                                 }
2051
2052                                 //
2053                                 // One of them is a valuetype, but the other one is not.
2054                                 //
2055                                 if (!l.IsValueType || !r.IsValueType) {
2056                                         Error_OperatorCannotBeApplied ();
2057                                         return null;
2058                                 }
2059                         }
2060
2061                         // Only perform numeric promotions on:
2062                         // +, -, *, /, %, &, |, ^, ==, !=, <, >, <=, >=
2063                         //
2064                         if (oper == Operator.Addition || oper == Operator.Subtraction) {
2065                                 if (l.IsSubclassOf (TypeManager.delegate_type) &&
2066                                     r.IsSubclassOf (TypeManager.delegate_type)) {
2067
2068                                         Arguments = new ArrayList ();
2069                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
2070                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
2071
2072                                         if (oper == Operator.Addition)
2073                                                 method = TypeManager.delegate_combine_delegate_delegate;
2074                                         else
2075                                                 method = TypeManager.delegate_remove_delegate_delegate;
2076
2077                                         if (l != r) {
2078                                                 Error_OperatorCannotBeApplied ();
2079                                                 return null;
2080                                         }
2081
2082                                         DelegateOperation = true;
2083                                         type = l;
2084                                         return this;
2085                                 }
2086
2087                                 //
2088                                 // Pointer arithmetic:
2089                                 //
2090                                 // T* operator + (T* x, int y);
2091                                 // T* operator + (T* x, uint y);
2092                                 // T* operator + (T* x, long y);
2093                                 // T* operator + (T* x, ulong y);
2094                                 //
2095                                 // T* operator + (int y,   T* x);
2096                                 // T* operator + (uint y,  T *x);
2097                                 // T* operator + (long y,  T *x);
2098                                 // T* operator + (ulong y, T *x);
2099                                 //
2100                                 // T* operator - (T* x, int y);
2101                                 // T* operator - (T* x, uint y);
2102                                 // T* operator - (T* x, long y);
2103                                 // T* operator - (T* x, ulong y);
2104                                 //
2105                                 // long operator - (T* x, T *y)
2106                                 //
2107                                 if (l.IsPointer){
2108                                         if (r.IsPointer && oper == Operator.Subtraction){
2109                                                 if (r == l)
2110                                                         return new PointerArithmetic (
2111                                                                 false, left, right, TypeManager.int64_type,
2112                                                                 loc);
2113                                         } else if (is_32_or_64 (r))
2114                                                 return new PointerArithmetic (
2115                                                         oper == Operator.Addition, left, right, l, loc);
2116                                 } else if (r.IsPointer && is_32_or_64 (l) && oper == Operator.Addition)
2117                                         return new PointerArithmetic (
2118                                                 true, right, left, r, loc);
2119                         }
2120
2121                         //
2122                         // Enumeration operators
2123                         //
2124                         bool lie = TypeManager.IsEnumType (l);
2125                         bool rie = TypeManager.IsEnumType (r);
2126                         if (lie || rie){
2127                                 Expression temp;
2128
2129                                 // U operator - (E e, E f)
2130                                 if (lie && rie && oper == Operator.Subtraction){
2131                                         if (l == r){
2132                                                 type = TypeManager.EnumToUnderlying (l);
2133                                                 return this;
2134                                         }
2135                                         Error_OperatorCannotBeApplied ();
2136                                         return null;
2137                                 }
2138
2139                                 //
2140                                 // operator + (E e, U x)
2141                                 // operator - (E e, U x)
2142                                 //
2143                                 if (oper == Operator.Addition || oper == Operator.Subtraction){
2144                                         Type enum_type = lie ? l : r;
2145                                         Type other_type = lie ? r : l;
2146                                         Type underlying_type = TypeManager.EnumToUnderlying (enum_type);
2147 ;
2148
2149                                         if (underlying_type != other_type){
2150                                                 Error_OperatorCannotBeApplied ();
2151                                                 return null;
2152                                         }
2153
2154                                         type = enum_type;
2155                                         return this;
2156                                 }
2157
2158                                 if (!rie){
2159                                         temp = ConvertImplicit (ec, right, l, loc);
2160                                         if (temp != null)
2161                                                 right = temp;
2162                                         else {
2163                                                 Error_OperatorCannotBeApplied ();
2164                                                 return null;
2165                                         }
2166                                 } if (!lie){
2167                                         temp = ConvertImplicit (ec, left, r, loc);
2168                                         if (temp != null){
2169                                                 left = temp;
2170                                                 l = r;
2171                                         } else {
2172                                                 Error_OperatorCannotBeApplied ();
2173                                                 return null;
2174                                         }
2175                                 }
2176
2177                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2178                                     oper == Operator.LessThanOrEqual || oper == Operator.LessThan ||
2179                                     oper == Operator.GreaterThanOrEqual || oper == Operator.GreaterThan){
2180                                         type = TypeManager.bool_type;
2181                                         return this;
2182                                 }
2183
2184                                 if (oper == Operator.BitwiseAnd ||
2185                                     oper == Operator.BitwiseOr ||
2186                                     oper == Operator.ExclusiveOr){
2187                                         type = l;
2188                                         return this;
2189                                 }
2190                                 Error_OperatorCannotBeApplied ();
2191                                 return null;
2192                         }
2193
2194                         if (oper == Operator.LeftShift || oper == Operator.RightShift)
2195                                 return CheckShiftArguments (ec);
2196
2197                         if (oper == Operator.LogicalOr || oper == Operator.LogicalAnd){
2198                                 if (l != TypeManager.bool_type || r != TypeManager.bool_type){
2199                                         Error_OperatorCannotBeApplied ();
2200                                         return null;
2201                                 }
2202
2203                                 type = TypeManager.bool_type;
2204                                 return this;
2205                         }
2206
2207                         //
2208                         // operator & (bool x, bool y)
2209                         // operator | (bool x, bool y)
2210                         // operator ^ (bool x, bool y)
2211                         //
2212                         if (l == TypeManager.bool_type && r == TypeManager.bool_type){
2213                                 if (oper == Operator.BitwiseAnd ||
2214                                     oper == Operator.BitwiseOr ||
2215                                     oper == Operator.ExclusiveOr){
2216                                         type = l;
2217                                         return this;
2218                                 }
2219                         }
2220
2221                         //
2222                         // Pointer comparison
2223                         //
2224                         if (l.IsPointer && r.IsPointer){
2225                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2226                                     oper == Operator.LessThan || oper == Operator.LessThanOrEqual ||
2227                                     oper == Operator.GreaterThan || oper == Operator.GreaterThanOrEqual){
2228                                         type = TypeManager.bool_type;
2229                                         return this;
2230                                 }
2231                         }
2232
2233                         //
2234                         // We are dealing with numbers
2235                         //
2236                         if (overload_failed){
2237                                 Error_OperatorCannotBeApplied ();
2238                                 return null;
2239                         }
2240
2241                         //
2242                         // This will leave left or right set to null if there is an error
2243                         //
2244                         DoNumericPromotions (ec, l, r);
2245                         if (left == null || right == null){
2246                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
2247                                 return null;
2248                         }
2249
2250                         //
2251                         // reload our cached types if required
2252                         //
2253                         l = left.Type;
2254                         r = right.Type;
2255
2256                         if (oper == Operator.BitwiseAnd ||
2257                             oper == Operator.BitwiseOr ||
2258                             oper == Operator.ExclusiveOr){
2259                                 if (l == r){
2260                                         if (!((l == TypeManager.int32_type) ||
2261                                               (l == TypeManager.uint32_type) ||
2262                                               (l == TypeManager.int64_type) ||
2263                                               (l == TypeManager.uint64_type)))
2264                                                 type = l;
2265                                 } else {
2266                                         Error_OperatorCannotBeApplied ();
2267                                         return null;
2268                                 }
2269                         }
2270
2271                         if (oper == Operator.Equality ||
2272                             oper == Operator.Inequality ||
2273                             oper == Operator.LessThanOrEqual ||
2274                             oper == Operator.LessThan ||
2275                             oper == Operator.GreaterThanOrEqual ||
2276                             oper == Operator.GreaterThan){
2277                                 type = TypeManager.bool_type;
2278                         }
2279
2280                         return this;
2281                 }
2282
2283                 public override Expression DoResolve (EmitContext ec)
2284                 {
2285                         left = left.Resolve (ec);
2286                         right = right.Resolve (ec);
2287
2288                         if (left == null || right == null)
2289                                 return null;
2290
2291                         if (left.Type == null)
2292                                 throw new Exception (
2293                                         "Resolve returned non null, but did not set the type! (" +
2294                                         left + ") at Line: " + loc.Row);
2295                         if (right.Type == null)
2296                                 throw new Exception (
2297                                         "Resolve returned non null, but did not set the type! (" +
2298                                         right + ") at Line: "+ loc.Row);
2299
2300                         eclass = ExprClass.Value;
2301
2302                         if (left is Constant && right is Constant){
2303                                 Expression e = ConstantFold.BinaryFold (
2304                                         ec, oper, (Constant) left, (Constant) right, loc);
2305                                 if (e != null)
2306                                         return e;
2307                         }
2308
2309                         return ResolveOperator (ec);
2310                 }
2311
2312                 /// <remarks>
2313                 ///   EmitBranchable is called from Statement.EmitBoolExpression in the
2314                 ///   context of a conditional bool expression.  This function will return
2315                 ///   false if it is was possible to use EmitBranchable, or true if it was.
2316                 ///
2317                 ///   The expression's code is generated, and we will generate a branch to 'target'
2318                 ///   if the resulting expression value is equal to isTrue
2319                 /// </remarks>
2320                 public bool EmitBranchable (EmitContext ec, Label target, bool onTrue)
2321                 {
2322                         if (method != null)
2323                                 return false;
2324
2325                         ILGenerator ig = ec.ig;
2326
2327                         //
2328                         // This is more complicated than it looks, but its just to avoid
2329                         // duplicated tests: basically, we allow ==, !=, >, <, >= and <=
2330                         // but on top of that we want for == and != to use a special path
2331                         // if we are comparing against null
2332                         //
2333                         if (oper == Operator.Equality || oper == Operator.Inequality){
2334                                 bool my_on_true = oper == Operator.Inequality ? onTrue : !onTrue;
2335
2336                                 if (left is NullLiteral){
2337                                         right.Emit (ec);
2338                                         if (my_on_true)
2339                                                 ig.Emit (OpCodes.Brtrue, target);
2340                                         else
2341                                                 ig.Emit (OpCodes.Brfalse, target);
2342                                         return true;
2343                                 } else if (right is NullLiteral){
2344                                         left.Emit (ec);
2345                                         if (my_on_true)
2346                                                 ig.Emit (OpCodes.Brtrue, target);
2347                                         else
2348                                                 ig.Emit (OpCodes.Brfalse, target);
2349                                         return true;
2350                                 }
2351                         } else if (!(oper == Operator.LessThan ||
2352                                       oper == Operator.GreaterThan ||
2353                                       oper == Operator.LessThanOrEqual ||
2354                                       oper == Operator.GreaterThanOrEqual))
2355                                 return false;
2356
2357
2358
2359                         left.Emit (ec);
2360                         right.Emit (ec);
2361
2362                         bool isUnsigned = is_unsigned (left.Type);
2363
2364                         switch (oper){
2365                         case Operator.Equality:
2366                                 if (onTrue)
2367                                         ig.Emit (OpCodes.Beq, target);
2368                                 else
2369                                         ig.Emit (OpCodes.Bne_Un, target);
2370                                 break;
2371
2372                         case Operator.Inequality:
2373                                 if (onTrue)
2374                                         ig.Emit (OpCodes.Bne_Un, target);
2375                                 else
2376                                         ig.Emit (OpCodes.Beq, target);
2377                                 break;
2378
2379                         case Operator.LessThan:
2380                                 if (onTrue)
2381                                         if (isUnsigned)
2382                                                 ig.Emit (OpCodes.Blt_Un, target);
2383                                         else
2384                                                 ig.Emit (OpCodes.Blt, target);
2385                                 else
2386                                         if (isUnsigned)
2387                                                 ig.Emit (OpCodes.Bge_Un, target);
2388                                         else
2389                                                 ig.Emit (OpCodes.Bge, target);
2390                                 break;
2391
2392                         case Operator.GreaterThan:
2393                                 if (onTrue)
2394                                         if (isUnsigned)
2395                                                 ig.Emit (OpCodes.Bgt_Un, target);
2396                                         else
2397                                                 ig.Emit (OpCodes.Bgt, target);
2398                                 else
2399                                         if (isUnsigned)
2400                                                 ig.Emit (OpCodes.Ble_Un, target);
2401                                         else
2402                                                 ig.Emit (OpCodes.Ble, target);
2403                                 break;
2404
2405                         case Operator.LessThanOrEqual:
2406                                 if (onTrue)
2407                                         if (isUnsigned)
2408                                                 ig.Emit (OpCodes.Ble_Un, target);
2409                                         else
2410                                                 ig.Emit (OpCodes.Ble, target);
2411                                 else
2412                                         if (isUnsigned)
2413                                                 ig.Emit (OpCodes.Bgt_Un, target);
2414                                         else
2415                                                 ig.Emit (OpCodes.Bgt, target);
2416                                 break;
2417
2418
2419                         case Operator.GreaterThanOrEqual:
2420                                 if (onTrue)
2421                                         if (isUnsigned)
2422                                                 ig.Emit (OpCodes.Bge_Un, target);
2423                                         else
2424                                                 ig.Emit (OpCodes.Bge, target);
2425                                 else
2426                                         if (isUnsigned)
2427                                                 ig.Emit (OpCodes.Blt_Un, target);
2428                                         else
2429                                                 ig.Emit (OpCodes.Blt, target);
2430                                 break;
2431
2432                         default:
2433                                 return false;
2434                         }
2435
2436                         return true;
2437                 }
2438
2439                 public override void Emit (EmitContext ec)
2440                 {
2441                         ILGenerator ig = ec.ig;
2442                         Type l = left.Type;
2443                         Type r = right.Type;
2444                         OpCode opcode;
2445
2446                         if (method != null) {
2447
2448                                 // Note that operators are static anyway
2449
2450                                 if (Arguments != null)
2451                                         Invocation.EmitArguments (ec, method, Arguments);
2452
2453                                 if (method is MethodInfo)
2454                                         ig.Emit (OpCodes.Call, (MethodInfo) method);
2455                                 else
2456                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
2457
2458                                 if (DelegateOperation)
2459                                         ig.Emit (OpCodes.Castclass, type);
2460
2461                                 return;
2462                         }
2463
2464                         //
2465                         // Handle short-circuit operators differently
2466                         // than the rest
2467                         //
2468                         if (oper == Operator.LogicalAnd){
2469                                 Label load_zero = ig.DefineLabel ();
2470                                 Label end = ig.DefineLabel ();
2471
2472                                 left.Emit (ec);
2473                                 ig.Emit (OpCodes.Brfalse, load_zero);
2474                                 right.Emit (ec);
2475                                 ig.Emit (OpCodes.Br, end);
2476                                 ig.MarkLabel (load_zero);
2477                                 ig.Emit (OpCodes.Ldc_I4_0);
2478                                 ig.MarkLabel (end);
2479                                 return;
2480                         } else if (oper == Operator.LogicalOr){
2481                                 Label load_one = ig.DefineLabel ();
2482                                 Label end = ig.DefineLabel ();
2483
2484                                 left.Emit (ec);
2485                                 ig.Emit (OpCodes.Brtrue, load_one);
2486                                 right.Emit (ec);
2487                                 ig.Emit (OpCodes.Br, end);
2488                                 ig.MarkLabel (load_one);
2489                                 ig.Emit (OpCodes.Ldc_I4_1);
2490                                 ig.MarkLabel (end);
2491                                 return;
2492                         }
2493
2494                         left.Emit (ec);
2495                         right.Emit (ec);
2496
2497                         switch (oper){
2498                         case Operator.Multiply:
2499                                 if (ec.CheckState){
2500                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2501                                                 opcode = OpCodes.Mul_Ovf;
2502                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2503                                                 opcode = OpCodes.Mul_Ovf_Un;
2504                                         else
2505                                                 opcode = OpCodes.Mul;
2506                                 } else
2507                                         opcode = OpCodes.Mul;
2508
2509                                 break;
2510
2511                         case Operator.Division:
2512                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2513                                         opcode = OpCodes.Div_Un;
2514                                 else
2515                                         opcode = OpCodes.Div;
2516                                 break;
2517
2518                         case Operator.Modulus:
2519                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2520                                         opcode = OpCodes.Rem_Un;
2521                                 else
2522                                         opcode = OpCodes.Rem;
2523                                 break;
2524
2525                         case Operator.Addition:
2526                                 if (ec.CheckState){
2527                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2528                                                 opcode = OpCodes.Add_Ovf;
2529                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2530                                                 opcode = OpCodes.Add_Ovf_Un;
2531                                         else
2532                                                 opcode = OpCodes.Add;
2533                                 } else
2534                                         opcode = OpCodes.Add;
2535                                 break;
2536
2537                         case Operator.Subtraction:
2538                                 if (ec.CheckState){
2539                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2540                                                 opcode = OpCodes.Sub_Ovf;
2541                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2542                                                 opcode = OpCodes.Sub_Ovf_Un;
2543                                         else
2544                                                 opcode = OpCodes.Sub;
2545                                 } else
2546                                         opcode = OpCodes.Sub;
2547                                 break;
2548
2549                         case Operator.RightShift:
2550                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2551                                         opcode = OpCodes.Shr_Un;
2552                                 else
2553                                         opcode = OpCodes.Shr;
2554                                 break;
2555
2556                         case Operator.LeftShift:
2557                                 opcode = OpCodes.Shl;
2558                                 break;
2559
2560                         case Operator.Equality:
2561                                 opcode = OpCodes.Ceq;
2562                                 break;
2563
2564                         case Operator.Inequality:
2565                                 ec.ig.Emit (OpCodes.Ceq);
2566                                 ec.ig.Emit (OpCodes.Ldc_I4_0);
2567
2568                                 opcode = OpCodes.Ceq;
2569                                 break;
2570
2571                         case Operator.LessThan:
2572                                 opcode = OpCodes.Clt;
2573                                 break;
2574
2575                         case Operator.GreaterThan:
2576                                 opcode = OpCodes.Cgt;
2577                                 break;
2578
2579                         case Operator.LessThanOrEqual:
2580                                 ec.ig.Emit (OpCodes.Cgt);
2581                                 ec.ig.Emit (OpCodes.Ldc_I4_0);
2582
2583                                 opcode = OpCodes.Ceq;
2584                                 break;
2585
2586                         case Operator.GreaterThanOrEqual:
2587                                 ec.ig.Emit (OpCodes.Clt);
2588                                 ec.ig.Emit (OpCodes.Ldc_I4_1);
2589
2590                                 opcode = OpCodes.Sub;
2591                                 break;
2592
2593                         case Operator.BitwiseOr:
2594                                 opcode = OpCodes.Or;
2595                                 break;
2596
2597                         case Operator.BitwiseAnd:
2598                                 opcode = OpCodes.And;
2599                                 break;
2600
2601                         case Operator.ExclusiveOr:
2602                                 opcode = OpCodes.Xor;
2603                                 break;
2604
2605                         default:
2606                                 throw new Exception ("This should not happen: Operator = "
2607                                                      + oper.ToString ());
2608                         }
2609
2610                         ig.Emit (opcode);
2611                 }
2612
2613                 public bool IsBuiltinOperator {
2614                         get {
2615                                 return method == null;
2616                         }
2617                 }
2618         }
2619
2620         public class PointerArithmetic : Expression {
2621                 Expression left, right;
2622                 bool is_add;
2623
2624                 //
2625                 // We assume that 'l' is always a pointer
2626                 //
2627                 public PointerArithmetic (bool is_addition, Expression l, Expression r, Type t,
2628                                           Location loc)
2629                 {
2630                         type = t;
2631                         eclass = ExprClass.Variable;
2632                         this.loc = loc;
2633                         left = l;
2634                         right = r;
2635                         is_add = is_addition;
2636                 }
2637
2638                 public override Expression DoResolve (EmitContext ec)
2639                 {
2640                         //
2641                         // We are born fully resolved
2642                         //
2643                         return this;
2644                 }
2645
2646                 public override void Emit (EmitContext ec)
2647                 {
2648                         Type op_type = left.Type;
2649                         ILGenerator ig = ec.ig;
2650                         int size = GetTypeSize (op_type.GetElementType ());
2651
2652                         if (right.Type.IsPointer){
2653                                 //
2654                                 // handle (pointer - pointer)
2655                                 //
2656                                 left.Emit (ec);
2657                                 right.Emit (ec);
2658                                 ig.Emit (OpCodes.Sub);
2659
2660                                 if (size != 1){
2661                                         if (size == 0)
2662                                                 ig.Emit (OpCodes.Sizeof, op_type);
2663                                         else
2664                                                 IntLiteral.EmitInt (ig, size);
2665                                         ig.Emit (OpCodes.Div);
2666                                 }
2667                                 ig.Emit (OpCodes.Conv_I8);
2668                         } else {
2669                                 //
2670                                 // handle + and - on (pointer op int)
2671                                 //
2672                                 left.Emit (ec);
2673                                 ig.Emit (OpCodes.Conv_I);
2674                                 right.Emit (ec);
2675                                 if (size != 1){
2676                                         if (size == 0)
2677                                                 ig.Emit (OpCodes.Sizeof, op_type);
2678                                         else
2679                                                 IntLiteral.EmitInt (ig, size);
2680                                         ig.Emit (OpCodes.Mul);
2681                                 }
2682                                 if (is_add)
2683                                         ig.Emit (OpCodes.Add);
2684                                 else
2685                                         ig.Emit (OpCodes.Sub);
2686                         }
2687                 }
2688         }
2689
2690         /// <summary>
2691         ///   Implements the ternary conditional operator (?:)
2692         /// </summary>
2693         public class Conditional : Expression {
2694                 Expression expr, trueExpr, falseExpr;
2695
2696                 public Conditional (Expression expr, Expression trueExpr, Expression falseExpr, Location l)
2697                 {
2698                         this.expr = expr;
2699                         this.trueExpr = trueExpr;
2700                         this.falseExpr = falseExpr;
2701                         this.loc = l;
2702                 }
2703
2704                 public Expression Expr {
2705                         get {
2706                                 return expr;
2707                         }
2708                 }
2709
2710                 public Expression TrueExpr {
2711                         get {
2712                                 return trueExpr;
2713                         }
2714                 }
2715
2716                 public Expression FalseExpr {
2717                         get {
2718                                 return falseExpr;
2719                         }
2720                 }
2721
2722                 public override Expression DoResolve (EmitContext ec)
2723                 {
2724                         expr = expr.Resolve (ec);
2725
2726                         if (expr == null)
2727                                 return null;
2728
2729                         if (expr.Type != TypeManager.bool_type)
2730                                 expr = Expression.ConvertImplicitRequired (
2731                                         ec, expr, TypeManager.bool_type, loc);
2732
2733                         trueExpr = trueExpr.Resolve (ec);
2734                         falseExpr = falseExpr.Resolve (ec);
2735
2736                         if (trueExpr == null || falseExpr == null)
2737                                 return null;
2738
2739                         eclass = ExprClass.Value;
2740                         if (trueExpr.Type == falseExpr.Type)
2741                                 type = trueExpr.Type;
2742                         else {
2743                                 Expression conv;
2744                                 Type true_type = trueExpr.Type;
2745                                 Type false_type = falseExpr.Type;
2746
2747                                 if (trueExpr is NullLiteral){
2748                                         type = false_type;
2749                                         return this;
2750                                 } else if (falseExpr is NullLiteral){
2751                                         type = true_type;
2752                                         return this;
2753                                 }
2754
2755                                 //
2756                                 // First, if an implicit conversion exists from trueExpr
2757                                 // to falseExpr, then the result type is of type falseExpr.Type
2758                                 //
2759                                 conv = ConvertImplicit (ec, trueExpr, false_type, loc);
2760                                 if (conv != null){
2761                                         //
2762                                         // Check if both can convert implicitl to each other's type
2763                                         //
2764                                         if (ConvertImplicit (ec, falseExpr, true_type, loc) != null){
2765                                                 Error (172,
2766                                                        "Can not compute type of conditional expression " +
2767                                                        "as '" + TypeManager.MonoBASIC_Name (trueExpr.Type) +
2768                                                        "' and '" + TypeManager.MonoBASIC_Name (falseExpr.Type) +
2769                                                        "' convert implicitly to each other");
2770                                                 return null;
2771                                         }
2772                                         type = false_type;
2773                                         trueExpr = conv;
2774                                 } else if ((conv = ConvertImplicit(ec, falseExpr, true_type,loc))!= null){
2775                                         type = true_type;
2776                                         falseExpr = conv;
2777                                 } else {
2778                                         Error (173, "The type of the conditional expression can " +
2779                                                "not be computed because there is no implicit conversion" +
2780                                                " from '" + TypeManager.MonoBASIC_Name (trueExpr.Type) + "'" +
2781                                                " and '" + TypeManager.MonoBASIC_Name (falseExpr.Type) + "'");
2782                                         return null;
2783                                 }
2784                         }
2785
2786                         if (expr is BoolConstant){
2787                                 BoolConstant bc = (BoolConstant) expr;
2788
2789                                 if (bc.Value)
2790                                         return trueExpr;
2791                                 else
2792                                         return falseExpr;
2793                         }
2794
2795                         return this;
2796                 }
2797
2798                 public override void Emit (EmitContext ec)
2799                 {
2800                         ILGenerator ig = ec.ig;
2801                         Label false_target = ig.DefineLabel ();
2802                         Label end_target = ig.DefineLabel ();
2803
2804                         Statement.EmitBoolExpression (ec, expr, false_target, false);
2805                         trueExpr.Emit (ec);
2806                         ig.Emit (OpCodes.Br, end_target);
2807                         ig.MarkLabel (false_target);
2808                         falseExpr.Emit (ec);
2809                         ig.MarkLabel (end_target);
2810                 }
2811
2812         }
2813
2814         /// <summary>
2815         ///   Local variables
2816         /// </summary>
2817         public class LocalVariableReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
2818                 public readonly string Name;
2819                 public readonly Block Block;
2820                 VariableInfo variable_info;
2821                 bool is_readonly;
2822
2823                 public LocalVariableReference (Block block, string name, Location l)
2824                 {
2825                         Block = block;
2826                         Name = name;
2827                         loc = l;
2828                         eclass = ExprClass.Variable;
2829                 }
2830
2831                 // Setting 'is_readonly' to false will allow you to create a writable
2832                 // reference to a read-only variable.  This is used by foreach and using.
2833                 public LocalVariableReference (Block block, string name, Location l,
2834                                                VariableInfo variable_info, bool is_readonly)
2835                         : this (block, name, l)
2836                 {
2837                         this.variable_info = variable_info;
2838                         this.is_readonly = is_readonly;
2839                 }
2840
2841                 public VariableInfo VariableInfo {
2842                         get {
2843                                 if (variable_info == null) {
2844                                         variable_info = Block.GetVariableInfo (Name);
2845                                         is_readonly = variable_info.ReadOnly;
2846                                 }
2847                                 return variable_info;
2848                         }
2849                 }
2850
2851                 public bool IsAssigned (EmitContext ec, Location loc)
2852                 {
2853                         return VariableInfo.IsAssigned (ec, loc);
2854                 }
2855
2856                 public bool IsFieldAssigned (EmitContext ec, string name, Location loc)
2857                 {
2858                         return VariableInfo.IsFieldAssigned (ec, name, loc);
2859                 }
2860
2861                 public void SetAssigned (EmitContext ec)
2862                 {
2863                         VariableInfo.SetAssigned (ec);
2864                 }
2865
2866                 public void SetFieldAssigned (EmitContext ec, string name)
2867                 {
2868                         VariableInfo.SetFieldAssigned (ec, name);
2869                 }
2870
2871                 public bool IsReadOnly {
2872                         get {
2873                                 if (variable_info == null) {
2874                                         variable_info = Block.GetVariableInfo (Name);
2875                                         is_readonly = variable_info.ReadOnly;
2876                                 }
2877                                 return is_readonly;
2878                         }
2879                 }
2880
2881                 public override Expression DoResolve (EmitContext ec)
2882                 {
2883                         VariableInfo vi = VariableInfo;
2884
2885                         if (Block.IsConstant (Name)) {
2886                                 Expression e = Block.GetConstantExpression (Name);
2887
2888                                 vi.Used = true;
2889                                 return e;
2890                         }
2891
2892                         if (ec.DoFlowAnalysis && !IsAssigned (ec, loc))
2893                                 return null;
2894
2895                         type = vi.VariableType;
2896                         return this;
2897                 }
2898
2899                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
2900                 {
2901                         VariableInfo vi = VariableInfo;
2902
2903                         if (ec.DoFlowAnalysis)
2904                                 ec.SetVariableAssigned (vi);
2905
2906                         Expression e = DoResolve (ec);
2907
2908                         if (e == null)
2909                                 return null;
2910
2911                         if (is_readonly){
2912                                 Error (1604, "cannot assign to '" + Name + "' because it is readonly");
2913                                 return null;
2914                         }
2915
2916                         return this;
2917                 }
2918
2919                 public override void Emit (EmitContext ec)
2920                 {
2921                         VariableInfo vi = VariableInfo;
2922                         ILGenerator ig = ec.ig;
2923
2924                         ig.Emit (OpCodes.Ldloc, vi.LocalBuilder);
2925                         vi.Used = true;
2926                 }
2927
2928                 public void EmitAssign (EmitContext ec, Expression source)
2929                 {
2930                         ILGenerator ig = ec.ig;
2931                         VariableInfo vi = VariableInfo;
2932
2933                         vi.Assigned = true;
2934
2935                         source.Emit (ec);
2936
2937                         ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
2938                 }
2939
2940                 public void AddressOf (EmitContext ec, AddressOp mode)
2941                 {
2942                         VariableInfo vi = VariableInfo;
2943
2944                         ec.ig.Emit (OpCodes.Ldloca, vi.LocalBuilder);
2945                 }
2946         }
2947
2948         /// <summary>
2949         ///   This represents a reference to a parameter in the intermediate
2950         ///   representation.
2951         /// </summary>
2952         public class ParameterReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
2953                 Parameters pars;
2954                 String name;
2955                 int idx;
2956                 public Parameter.Modifier mod;
2957                 public bool is_ref, is_out;
2958
2959                 public ParameterReference (Parameters pars, int idx, string name, Location loc)
2960                 {
2961                         this.pars = pars;
2962                         this.idx  = idx;
2963                         this.name = name;
2964                         this.loc = loc;
2965                         eclass = ExprClass.Variable;
2966                 }
2967
2968                 public bool IsAssigned (EmitContext ec, Location loc)
2969                 {
2970                         if (!is_out || !ec.DoFlowAnalysis)
2971                                 return true;
2972
2973                         if (!ec.CurrentBranching.IsParameterAssigned (idx)) {
2974                                 Report.Error (165, loc,
2975                                               "Use of unassigned local variable '" + name + "'");
2976                                 return false;
2977                         }
2978
2979                         return true;
2980                 }
2981
2982                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
2983                 {
2984                         if (!is_out || !ec.DoFlowAnalysis)
2985                                 return true;
2986
2987                         if (ec.CurrentBranching.IsParameterAssigned (idx))
2988                                 return true;
2989
2990                         if (!ec.CurrentBranching.IsParameterAssigned (idx, field_name)) {
2991                                 Report.Error (170, loc,
2992                                               "Use of possibly unassigned field '" + field_name + "'");
2993                                 return false;
2994                         }
2995
2996                         return true;
2997                 }
2998
2999                 public void SetAssigned (EmitContext ec)
3000                 {
3001                         if (is_out && ec.DoFlowAnalysis)
3002                                 ec.CurrentBranching.SetParameterAssigned (idx);
3003                 }
3004
3005                 public void SetFieldAssigned (EmitContext ec, string field_name)
3006                 {
3007                         if (is_out && ec.DoFlowAnalysis)
3008                                 ec.CurrentBranching.SetParameterAssigned (idx, field_name);
3009                 }
3010
3011                 //
3012                 // Notice that for ref/out parameters, the type exposed is not the
3013                 // same type exposed externally.
3014                 //
3015                 // for "ref int a":
3016                 //   externally we expose "int&"
3017                 //   here we expose       "int".
3018                 //
3019                 // We record this in "is_ref".  This means that the type system can treat
3020                 // the type as it is expected, but when we generate the code, we generate
3021                 // the alternate kind of code.
3022                 //
3023                 public override Expression DoResolve (EmitContext ec)
3024                 {
3025                         type = pars.GetParameterInfo (ec.DeclSpace, idx, out mod);
3026                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3027                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3028                         eclass = ExprClass.Variable;
3029
3030                         if (is_out && ec.DoFlowAnalysis && !IsAssigned (ec, loc))
3031                                 return null;
3032
3033                         return this;
3034                 }
3035
3036                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3037                 {
3038                         type = pars.GetParameterInfo (ec.DeclSpace, idx, out mod);
3039                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3040                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3041                         eclass = ExprClass.Variable;
3042
3043                         if (is_out && ec.DoFlowAnalysis)
3044                                 ec.SetParameterAssigned (idx);
3045
3046                         return this;
3047                 }
3048
3049                 static void EmitLdArg (ILGenerator ig, int x)
3050                 {
3051                         if (x <= 255){
3052                                 switch (x){
3053                                 case 0: ig.Emit (OpCodes.Ldarg_0); break;
3054                                 case 1: ig.Emit (OpCodes.Ldarg_1); break;
3055                                 case 2: ig.Emit (OpCodes.Ldarg_2); break;
3056                                 case 3: ig.Emit (OpCodes.Ldarg_3); break;
3057                                 default: ig.Emit (OpCodes.Ldarg_S, (byte) x); break;
3058                                 }
3059                         } else
3060                                 ig.Emit (OpCodes.Ldarg, x);
3061                 }
3062
3063                 //
3064                 // This method is used by parameters that are references, that are
3065                 // being passed as references:  we only want to pass the pointer (that
3066                 // is already stored in the parameter, not the address of the pointer,
3067                 // and not the value of the variable).
3068                 //
3069                 public void EmitLoad (EmitContext ec)
3070                 {
3071                         ILGenerator ig = ec.ig;
3072                         int arg_idx = idx;
3073
3074                         if (!ec.IsStatic)
3075                                 arg_idx++;
3076
3077                         EmitLdArg (ig, arg_idx);
3078                 }
3079
3080                 public override void Emit (EmitContext ec)
3081                 {
3082                         ILGenerator ig = ec.ig;
3083                         int arg_idx = idx;
3084
3085                         if (!ec.IsStatic)
3086                                 arg_idx++;
3087
3088                         EmitLdArg (ig, arg_idx);
3089
3090                         if (!is_ref)
3091                                 return;
3092
3093                         //
3094                         // If we are a reference, we loaded on the stack a pointer
3095                         // Now lets load the real value
3096                         //
3097                         LoadFromPtr (ig, type);
3098                 }
3099
3100                 public void EmitAssign (EmitContext ec, Expression source)
3101                 {
3102                         ILGenerator ig = ec.ig;
3103                         int arg_idx = idx;
3104
3105                         if (!ec.IsStatic)
3106                                 arg_idx++;
3107
3108                         if (is_ref)
3109                                 EmitLdArg (ig, arg_idx);
3110
3111                         source.Emit (ec);
3112
3113                         if (is_ref)
3114                                 StoreFromPtr (ig, type);
3115                         else {
3116                                 if (arg_idx <= 255)
3117                                         ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
3118                                 else
3119                                         ig.Emit (OpCodes.Starg, arg_idx);
3120                         }
3121                 }
3122
3123                 public void AddressOf (EmitContext ec, AddressOp mode)
3124                 {
3125                         int arg_idx = idx;
3126
3127                         if (!ec.IsStatic)
3128                                 arg_idx++;
3129
3130                         if (is_ref){
3131                                 if (arg_idx <= 255)
3132                                         ec.ig.Emit (OpCodes.Ldarg_S, (byte) arg_idx);
3133                                 else
3134                                         ec.ig.Emit (OpCodes.Ldarg, arg_idx);
3135                         } else {
3136                                 if (arg_idx <= 255)
3137                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
3138                                 else
3139                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
3140                         }
3141                 }
3142         }
3143
3144
3145         /// <summary>
3146         ///   Invocation of methods or delegates.
3147         /// </summary>
3148         public class Invocation : ExpressionStatement {
3149                 public ArrayList Arguments;
3150
3151                 public Expression expr;
3152                 MethodBase method = null;
3153                 bool is_base;
3154                 bool is_left_hand; // Needed for late bound calls
3155                 static Hashtable method_parameter_cache;
3156                 static MemberFilter CompareName;
3157
3158                 static Invocation ()
3159                 {
3160                         method_parameter_cache = new PtrHashtable ();
3161                 }
3162
3163                 //
3164                 // arguments is an ArrayList, but we do not want to typecast,
3165                 // as it might be null.
3166                 //
3167                 // FIXME: only allow expr to be a method invocation or a
3168                 // delegate invocation (7.5.5)
3169                 //
3170                 public Invocation (Expression expr, ArrayList arguments, Location l)
3171                 {
3172                         this.expr = expr;
3173                         Arguments = arguments;
3174                         loc = l;
3175                         CompareName = new MemberFilter (compare_name_filter);
3176                 }
3177
3178                 public Expression Expr {
3179                         get {
3180                                 return expr;
3181                         }
3182                 }
3183
3184                 /// <summary>
3185                 ///   Returns the Parameters (a ParameterData interface) for the
3186                 ///   Method 'mb'
3187                 /// </summary>
3188                 public static ParameterData GetParameterData (MethodBase mb)
3189                 {
3190                         object pd = method_parameter_cache [mb];
3191                         object ip;
3192
3193                         if (pd != null)
3194                                 return (ParameterData) pd;
3195
3196
3197                         ip = TypeManager.LookupParametersByBuilder (mb);
3198                         if (ip != null){
3199                                 method_parameter_cache [mb] = ip;
3200
3201                                 return (ParameterData) ip;
3202                         } else {
3203                                 ParameterInfo [] pi = mb.GetParameters ();
3204                                 ReflectionParameters rp = new ReflectionParameters (pi);
3205                                 method_parameter_cache [mb] = rp;
3206
3207                                 return (ParameterData) rp;
3208                         }
3209                 }
3210
3211                 /// <summary>
3212                 ///  Determines "better conversion" as specified in 7.4.2.3
3213                 ///  Returns : 1 if a->p is better
3214                 ///            0 if a->q or neither is better
3215                 /// </summary>
3216                 static int BetterConversion (EmitContext ec, Argument a, Type p, Type q, Location loc)
3217                 {
3218                         Type argument_type = a.Type;
3219                         Expression argument_expr = a.Expr;
3220
3221                         if (argument_type == null)
3222                                 throw new Exception ("Expression of type " + a.Expr + " does not resolve its type");
3223
3224                         //
3225                         // This is a special case since csc behaves this way. I can't find
3226                         // it anywhere in the spec but oh well ...
3227                         //
3228                         if (argument_expr is NullLiteral && p == TypeManager.string_type && q == TypeManager.object_type)
3229                                 return 1;
3230                         else if (argument_expr is NullLiteral && p == TypeManager.object_type && q == TypeManager.string_type)
3231                                 return 0;
3232
3233                         if (p == q)
3234                                 return 0;
3235
3236                         if (argument_type == p)
3237                                 return 1;
3238
3239                         if (argument_type == q)
3240                                 return 0;
3241
3242                         //
3243                         // Now probe whether an implicit constant expression conversion
3244                         // can be used.
3245                         //
3246                         // An implicit constant expression conversion permits the following
3247                         // conversions:
3248                         //
3249                         //    * A constant-expression of type 'int' can be converted to type
3250                         //      sbyte, byute, short, ushort, uint, ulong provided the value of
3251                         //      of the expression is withing the range of the destination type.
3252                         //
3253                         //    * A constant-expression of type long can be converted to type
3254                         //      ulong, provided the value of the constant expression is not negative
3255                         //
3256                         // FIXME: Note that this assumes that constant folding has
3257                         // taken place.  We dont do constant folding yet.
3258                         //
3259
3260                         if (argument_expr is IntConstant){
3261                                 IntConstant ei = (IntConstant) argument_expr;
3262                                 int value = ei.Value;
3263
3264                                 if (p == TypeManager.sbyte_type){
3265                                         if (value >= SByte.MinValue && value <= SByte.MaxValue)
3266                                                 return 1;
3267                                 } else if (p == TypeManager.byte_type){
3268                                         if (Byte.MinValue >= 0 && value <= Byte.MaxValue)
3269                                                 return 1;
3270                                 } else if (p == TypeManager.short_type){
3271                                         if (value >= Int16.MinValue && value <= Int16.MaxValue)
3272                                                 return 1;
3273                                 } else if (p == TypeManager.ushort_type){
3274                                         if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
3275                                                 return 1;
3276                                 } else if (p == TypeManager.uint32_type){
3277                                         //
3278                                         // we can optimize this case: a positive int32
3279                                         // always fits on a uint32
3280                                         //
3281                                         if (value >= 0)
3282                                                 return 1;
3283                                 } else if (p == TypeManager.uint64_type){
3284                                         //
3285                                         // we can optimize this case: a positive int32
3286                                         // always fits on a uint64
3287                                         //
3288                                         if (value >= 0)
3289                                                 return 1;
3290                                 }
3291                         } else if (argument_type == TypeManager.int64_type && argument_expr is LongConstant){
3292                                 LongConstant lc = (LongConstant) argument_expr;
3293
3294                                 if (p == TypeManager.uint64_type){
3295                                         if (lc.Value > 0)
3296                                                 return 1;
3297                                 }
3298                         }
3299
3300                         if (q == null) {
3301                                 Expression tmp = ConvertImplicit (ec, argument_expr, p, loc);
3302
3303                                 if (tmp != null)
3304                                         return 1;
3305                                 else
3306                                         return 0;
3307                         }
3308
3309                         Expression p_tmp = new EmptyExpression (p);
3310                         Expression q_tmp = new EmptyExpression (q);
3311
3312                         if (StandardConversionExists (p_tmp, q) == true &&
3313                             StandardConversionExists (q_tmp, p) == false)
3314                                 return 1;
3315
3316                         if (p == TypeManager.sbyte_type)
3317                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3318                                     q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3319                                         return 1;
3320
3321                         if (p == TypeManager.short_type)
3322                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3323                                     q == TypeManager.uint64_type)
3324                                         return 1;
3325
3326                         if (p == TypeManager.int32_type)
3327                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3328                                         return 1;
3329
3330                         if (p == TypeManager.int64_type)
3331                                 if (q == TypeManager.uint64_type)
3332                                         return 1;
3333
3334                         return 0;
3335                 }
3336
3337                 /// <summary>
3338                 ///  Determines "Better function"
3339                 /// </summary>
3340                 /// <remarks>
3341                 ///    and returns an integer indicating :
3342                 ///    0 if candidate ain't better
3343                 ///    1 if candidate is better than the current best match
3344                 /// </remarks>
3345                 static int BetterFunction (EmitContext ec, ArrayList args,
3346                                            MethodBase candidate, MethodBase best,
3347                                            bool expanded_form, Location loc)
3348                 {
3349                         ParameterData candidate_pd = GetParameterData (candidate);
3350                         ParameterData best_pd;
3351                         int argument_count;
3352
3353                         if (args == null)
3354                                 argument_count = 0;
3355                         else
3356                                 argument_count = args.Count;
3357
3358                         int cand_count = candidate_pd.Count;
3359
3360                         if (cand_count == 0 && argument_count == 0)
3361                                 return 1;
3362
3363                         if (candidate_pd.ParameterModifier (cand_count - 1) != Parameter.Modifier.PARAMS)
3364                                 if (cand_count != argument_count)
3365                                         return 0;
3366
3367                         if (best == null) {
3368                                 int x = 0;
3369
3370                                 if (argument_count == 0 && cand_count == 1 &&
3371                                     candidate_pd.ParameterModifier (cand_count - 1) == Parameter.Modifier.PARAMS)
3372                                         return 1;
3373
3374                                 for (int j = argument_count; j > 0;) {
3375                                         j--;
3376
3377                                         Argument a = (Argument) args [j];
3378                                         Type t = candidate_pd.ParameterType (j);
3379
3380                                         if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3381                                                 if (expanded_form)
3382                                                         t = t.GetElementType ();
3383
3384                                         x = BetterConversion (ec, a, t, null, loc);
3385
3386                                         if (x <= 0)
3387                                                 break;
3388                                 }
3389
3390                                 if (x > 0)
3391                                         return 1;
3392                                 else
3393                                         return 0;
3394                         }
3395
3396                         best_pd = GetParameterData (best);
3397
3398                         int rating1 = 0, rating2 = 0;
3399
3400                         for (int j = 0; j < argument_count; ++j) {
3401                                 int x, y;
3402
3403                                 Argument a = (Argument) args [j];
3404
3405                                 Type ct = candidate_pd.ParameterType (j);
3406                                 Type bt = best_pd.ParameterType (j);
3407
3408                                 if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3409                                         if (expanded_form)
3410                                                 ct = ct.GetElementType ();
3411
3412                                 if (best_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3413                                         if (expanded_form)
3414                                                 bt = bt.GetElementType ();
3415
3416                                 x = BetterConversion (ec, a, ct, bt, loc);
3417                                 y = BetterConversion (ec, a, bt, ct, loc);
3418
3419                                 if (x < y)
3420                                         return 0;
3421
3422                                 rating1 += x;
3423                                 rating2 += y;
3424                         }
3425
3426                         if (rating1 > rating2)
3427                                 return 1;
3428                         else
3429                                 return 0;
3430                 }
3431
3432                 public static string FullMethodDesc (MethodBase mb)
3433                 {
3434                         string ret_type = "";
3435
3436                         if (mb is MethodInfo)
3437                                 ret_type = TypeManager.MonoBASIC_Name (((MethodInfo) mb).ReturnType) + " ";
3438
3439                         StringBuilder sb = new StringBuilder (ret_type + mb.Name);
3440                         ParameterData pd = GetParameterData (mb);
3441
3442                         int count = pd.Count;
3443                         sb.Append (" (");
3444
3445                         for (int i = count; i > 0; ) {
3446                                 i--;
3447
3448                                 sb.Append (pd.ParameterDesc (count - i - 1));
3449                                 if (i != 0)
3450                                         sb.Append (", ");
3451                         }
3452
3453                         sb.Append (")");
3454                         return sb.ToString ();
3455                 }
3456
3457                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3458                 {
3459                         MemberInfo [] miset;
3460                         MethodGroupExpr union;
3461
3462                         if (mg1 == null){
3463                                 if (mg2 == null)
3464                                         return null;
3465                                 return (MethodGroupExpr) mg2;
3466                         } else {
3467                                 if (mg2 == null)
3468                                         return (MethodGroupExpr) mg1;
3469                         }
3470
3471                         MethodGroupExpr left_set = null, right_set = null;
3472                         int length1 = 0, length2 = 0;
3473
3474                         left_set = (MethodGroupExpr) mg1;
3475                         length1 = left_set.Methods.Length;
3476
3477                         right_set = (MethodGroupExpr) mg2;
3478                         length2 = right_set.Methods.Length;
3479
3480                         ArrayList common = new ArrayList ();
3481
3482                         foreach (MethodBase l in left_set.Methods){
3483                                 foreach (MethodBase r in right_set.Methods){
3484                                         if (l != r)
3485                                                 continue;
3486                                         common.Add (r);
3487                                         break;
3488                                 }
3489                         }
3490
3491                         miset = new MemberInfo [length1 + length2 - common.Count];
3492                         left_set.Methods.CopyTo (miset, 0);
3493
3494                         int k = length1;
3495
3496                         foreach (MemberInfo mi in right_set.Methods){
3497                                 if (!common.Contains (mi))
3498                                         miset [k++] = mi;
3499                         }
3500
3501                         union = new MethodGroupExpr (miset, loc);
3502
3503                         return union;
3504                 }
3505
3506                 /// <summary>
3507                 ///  Determines is the candidate method, if a params method, is applicable
3508                 ///  in its expanded form to the given set of arguments
3509                 /// </summary>
3510                 static bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments, MethodBase candidate)
3511                 {
3512                         int arg_count;
3513
3514                         if (arguments == null)
3515                                 arg_count = 0;
3516                         else
3517                                 arg_count = arguments.Count;
3518
3519                         ParameterData pd = GetParameterData (candidate);
3520
3521                         int pd_count = pd.Count;
3522
3523                         if (pd_count == 0)
3524                                 return false;
3525
3526                         if (pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS)
3527                                 return false;
3528
3529                         if (pd_count - 1 > arg_count)
3530                                 return false;
3531
3532                         if (pd_count == 1 && arg_count == 0)
3533                                 return true;
3534
3535                         //
3536                         // If we have come this far, the case which remains is when the number of parameters
3537                         // is less than or equal to the argument count.
3538                         //
3539                         for (int i = 0; i < pd_count - 1; ++i) {
3540
3541                                 Argument a = (Argument) arguments [i];
3542
3543                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3544                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3545                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3546                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3547
3548                                 if (a_mod == p_mod) {
3549
3550                                         if (a_mod == Parameter.Modifier.NONE)
3551                                                 if (!ImplicitConversionExists (ec, a.Expr, pd.ParameterType (i)))
3552                                                         return false;
3553
3554                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3555                                                 Type pt = pd.ParameterType (i);
3556
3557                                                 if (!pt.IsByRef)
3558                                                         pt = TypeManager.LookupType (pt.FullName + "&");
3559
3560                                                 if (pt != a.Type)
3561                                                         return false;
3562                                         }
3563                                 } else
3564                                         return false;
3565
3566                         }
3567
3568                         Type element_type = pd.ParameterType (pd_count - 1).GetElementType ();
3569
3570                         for (int i = pd_count - 1; i < arg_count; i++) {
3571                                 Argument a = (Argument) arguments [i];
3572
3573                                 if (!StandardConversionExists (a.Expr, element_type))
3574                                         return false;
3575                         }
3576
3577                         return true;
3578                 }
3579
3580                 static bool CheckParameterAgainstArgument (EmitContext ec, ParameterData pd, int i, Argument a, Type ptype)
3581                 {
3582                         Parameter.Modifier a_mod = a.GetParameterModifier () &
3583                                 ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3584                         Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3585                                 ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3586
3587                         if (a_mod == p_mod || (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
3588                                 if (a_mod == Parameter.Modifier.NONE)
3589                                         if (! (ImplicitConversionExists (ec, a.Expr, ptype) || RuntimeConversionExists (ec, a.Expr, ptype)) )
3590                                                 return false;
3591
3592                                 if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3593                                         Type pt = pd.ParameterType (i);
3594
3595                                         if (!pt.IsByRef)
3596                                                 pt = TypeManager.LookupType (pt.FullName + "&");
3597
3598                                         if (pt != a.Type)
3599                                                 return false;
3600                                 }
3601                         } else
3602                                 return false;
3603                         return true;
3604                 }
3605
3606                 /// <summary>
3607                 ///  Determines if the candidate method is applicable (section 14.4.2.1)
3608                 ///  to the given set of arguments
3609                 /// </summary>
3610                 static bool IsApplicable (EmitContext ec, ref ArrayList arguments, MethodBase candidate)
3611                 {
3612                         int arg_count, ps_count, po_count;
3613                         Type param_type;
3614
3615                         if (arguments == null)
3616                                 arg_count = 0;
3617                         else
3618                                 arg_count = arguments.Count;
3619
3620                         ParameterData pd = GetParameterData (candidate);
3621                         Parameters ps = GetFullParameters (candidate);
3622                         if (ps == null) {
3623                                 ps_count = 0;
3624                                 po_count = 0;
3625                         }
3626                         else {
3627                                 ps_count = ps.CountStandardParams();
3628                                 po_count = ps.CountOptionalParams();
3629                         }
3630                         int pd_count = pd.Count;
3631
3632                         // Validate argument count
3633                         if (po_count == 0) {
3634                                 if (arg_count != pd.Count)
3635                                         return false;
3636                         }
3637                         else {
3638                                 if ((arg_count < ps_count) || (arg_count > pd_count))
3639                                         return false;
3640                         }
3641
3642                         if (arg_count > 0) {
3643                                 for (int i = arg_count; i > 0 ; ) {
3644                                         i--;
3645
3646                                         Argument a = (Argument) arguments [i];
3647                                         if (a.ArgType == Argument.AType.NoArg) {
3648                                                 Parameter p = (Parameter) ps.FixedParameters[i];
3649                                                 a = new Argument (p.ParameterInitializer, Argument.AType.Expression);
3650                                                 param_type = p.ParameterInitializer.Type;
3651                                         }
3652                                         else {
3653                                                 param_type = pd.ParameterType (i);
3654                                                 if (ps != null) {
3655                                                         Parameter p = (Parameter) ps.FixedParameters[i];
3656                                                         bool IsDelegate = TypeManager.IsDelegateType (param_type);
3657
3658                                                         if (IsDelegate) {
3659                                                                 if (a.ArgType == Argument.AType.AddressOf) {
3660                                                                         a = new Argument ((Expression) a.Expr, Argument.AType.Expression);
3661                                                                         ArrayList args = new ArrayList();
3662                                                                         args.Add (a);
3663                                                                         string param_name = pd.ParameterDesc(i).Replace('+', '.');
3664                                                                         Expression pname = MonoBASIC.Parser.DecomposeQI (param_name, Location.Null);
3665
3666
3667                                                                         New temp_new = new New ((Expression)pname, args, Location.Null);
3668                                                                         Expression del_temp = temp_new.DoResolve(ec);
3669
3670                                                                         if (del_temp == null)
3671                                                                                 return false;
3672
3673                                                                         a = new Argument (del_temp, Argument.AType.Expression);
3674                                                                         if (!a.Resolve(ec, Location.Null))\r
3675                                                                                 return false;
3676                                                                 }
3677                                                         }
3678                                                         else {
3679                                                                 if (a.ArgType == Argument.AType.AddressOf)
3680                                                                         return false;
3681                                                         }
3682
3683                                                         if ((p.ModFlags & Parameter.Modifier.REF) != 0) {
3684                                                                 a = new Argument (a.Expr, Argument.AType.Ref);
3685                                                                 if (!a.Resolve(ec,Location.Null))
3686                                                                         return false;
3687                                                         }
3688                                                 }
3689                                         }
3690 \r
3691                                         if (!CheckParameterAgainstArgument (ec, pd, i, a, param_type))
3692                                                 return (false);
3693                                 }
3694                         }
3695                         else {
3696                                 // If we have no arguments AND the first parameter is optional
3697                                 // we must check for a candidate (the loop above wouldn't)
3698                                 if (po_count > 0) {
3699                                         ArrayList arglist = new ArrayList();
3700
3701                                         // Since we got so far, there's no need to check if
3702                                         // arguments are optional; we simply retrieve
3703                                         // parameter default values and build a brand-new
3704                                         // argument list.
3705
3706                                         for (int i = 0; i < ps.FixedParameters.Length; i++) {
3707                                                 Parameter p = ps.FixedParameters[i];
3708                                                 Argument a = new Argument (p.ParameterInitializer, Argument.AType.Expression);
3709                                                 a.Resolve(ec, Location.Null);
3710                                                 arglist.Add (a);
3711                                         }
3712                                         arguments = arglist;
3713                                         return true;
3714                                 }
3715                         }
3716                         // We've found a candidate, so we exchange the dummy NoArg arguments
3717                         // with new arguments containing the default value for that parameter
3718
3719                         ArrayList newarglist = new ArrayList();
3720                         for (int i = 0; i < arg_count; i++) {
3721                                 Argument a = (Argument) arguments [i];
3722                                 Parameter p = null;
3723
3724                                 if (ps != null)
3725                                         p = (Parameter) ps.FixedParameters[i];
3726
3727                                 if (a.ArgType == Argument.AType.NoArg){
3728                                         a = new Argument (p.ParameterInitializer, Argument.AType.Expression);
3729                                         a.Resolve(ec, Location.Null);
3730                                 }
3731
3732                                 // ToDo - This part is getting resolved second time within this function
3733                                 // This is a costly operation
3734                                 // The earlier resoved result should be used here.
3735                                 // Has to be done during compiler optimization.
3736                                 if (a.ArgType == Argument.AType.AddressOf) {
3737                                         param_type = pd.ParameterType (i);
3738                                         bool IsDelegate = TypeManager.IsDelegateType (param_type);
3739
3740                                         a = new Argument ((Expression) a.Expr, Argument.AType.Expression);
3741                                         ArrayList args = new ArrayList();
3742                                         args.Add (a);
3743                                         string param_name = pd.ParameterDesc(i).Replace('+', '.');
3744                                         Expression pname = MonoBASIC.Parser.DecomposeQI (param_name, Location.Null);
3745
3746                                         New temp_new = new New ((Expression)pname, args, Location.Null);
3747                                         Expression del_temp = temp_new.DoResolve(ec);
3748
3749                                         if (del_temp == null)
3750                                                 return false;
3751
3752                                         a = new Argument (del_temp, Argument.AType.Expression);
3753                                         if (!a.Resolve(ec, Location.Null))\r
3754                                                 return false;
3755                                 }
3756
3757                                 if ((p != null) && ((p.ModFlags & Parameter.Modifier.REF) != 0)) {
3758                                         a.ArgType = Argument.AType.Ref;
3759                                         a.Resolve(ec, Location.Null);
3760                                 }
3761                                 newarglist.Add(a);
3762                                 int n = pd_count - arg_count;
3763                                 if (n > 0) {
3764                                         for (int x = 0; x < n; x++) {
3765                                                 Parameter op = (Parameter) ps.FixedParameters[x + arg_count];
3766                                                 Argument b = new Argument (op.ParameterInitializer, Argument.AType.Expression);
3767                                                 b.Resolve(ec, Location.Null);
3768                                                 newarglist.Add (b);
3769                                         }
3770                                 }
3771                         }
3772                         arguments = newarglist;
3773                         return true;
3774                 }
3775
3776                 static bool compare_name_filter (MemberInfo m, object filterCriteria)
3777                 {
3778                         return (m.Name == ((string) filterCriteria));
3779                 }
3780
3781                 static Parameters GetFullParameters (MethodBase mb)
3782                 {
3783                         TypeContainer tc = TypeManager.LookupTypeContainer (mb.DeclaringType);
3784                         InternalParameters ip = TypeManager.LookupParametersByBuilder(mb);
3785
3786                         return (ip != null) ? ip.Parameters : null;
3787                 }
3788
3789                 // We need an overload for OverloadResolve because Invocation.DoResolve
3790                 // must pass Arguments by reference, since a later call to IsApplicable
3791                 // can change the argument list if optional parameters are defined
3792                 // in the method declaration
3793                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
3794                                                           ArrayList Arguments, Location loc)
3795                 {
3796                         ArrayList a = Arguments;
3797                         return OverloadResolve (ec, me, ref a, loc);
3798                 }
3799
3800                 /// <summary>
3801                 ///   Find the Applicable Function Members (7.4.2.1)
3802                 ///
3803                 ///   me: Method Group expression with the members to select.
3804                 ///       it might contain constructors or methods (or anything
3805                 ///       that maps to a method).
3806                 ///
3807                 ///   Arguments: ArrayList containing resolved Argument objects.
3808                 ///
3809                 ///   loc: The location if we want an error to be reported, or a Null
3810                 ///        location for "probing" purposes.
3811                 ///
3812                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3813                 ///            that is the best match of me on Arguments.
3814                 ///
3815                 /// </summary>
3816                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
3817                                                           ref ArrayList Arguments, Location loc)
3818                 {
3819                         ArrayList afm = new ArrayList ();
3820                         MethodBase method = null;
3821                         Type current_type = null;
3822                         int argument_count;
3823                         ArrayList candidates = new ArrayList ();
3824
3825                         foreach (MethodBase candidate in me.Methods){
3826                                 int x;
3827
3828                                 // If we're going one level higher in the class hierarchy, abort if
3829                                 // we already found an applicable method.
3830                                 if (candidate.DeclaringType != current_type) {
3831                                         current_type = candidate.DeclaringType;
3832                                         if (method != null)
3833                                                 break;
3834                                 }
3835
3836                                 // Check if candidate is applicable (section 14.4.2.1)
3837                                 if (!IsApplicable (ec, ref Arguments, candidate))
3838                                         continue;
3839
3840                                 candidates.Add (candidate);
3841                                 x = BetterFunction (ec, Arguments, candidate, method, false, loc);
3842
3843                                 if (x == 0)
3844                                         continue;
3845
3846                                 method = candidate;
3847                         }
3848
3849                         if (Arguments == null)
3850                                 argument_count = 0;
3851                         else
3852                                 argument_count = Arguments.Count;
3853
3854
3855                         //
3856                         // Now we see if we can find params functions, applicable in their expanded form
3857                         // since if they were applicable in their normal form, they would have been selected
3858                         // above anyways
3859                         //
3860                         bool chose_params_expanded = false;
3861
3862                         if (method == null) {
3863                                 candidates = new ArrayList ();
3864                                 foreach (MethodBase candidate in me.Methods){
3865                                         if (!IsParamsMethodApplicable (ec, Arguments, candidate))
3866                                                 continue;
3867
3868                                         candidates.Add (candidate);
3869
3870                                         int x = BetterFunction (ec, Arguments, candidate, method, true, loc);
3871                                         if (x == 0)
3872                                                 continue;
3873
3874                                         method = candidate;
3875                                         chose_params_expanded = true;
3876                                 }
3877                         }
3878
3879                         if (method == null) {
3880                                 //
3881                                 // Okay so we have failed to find anything so we
3882                                 // return by providing info about the closest match
3883                                 //
3884                                 for (int i = 0; i < me.Methods.Length; ++i) {
3885
3886                                         MethodBase c = (MethodBase) me.Methods [i];
3887                                         ParameterData pd = GetParameterData (c);
3888
3889                                         if (pd.Count != argument_count)
3890                                                 continue;
3891
3892                                         VerifyArgumentsCompat (ec, Arguments, argument_count, c, false,
3893                                                                null, loc);
3894                                 }
3895
3896                                 return null;
3897                         }
3898
3899                         //
3900                         // Now check that there are no ambiguities i.e the selected method
3901                         // should be better than all the others
3902                         //
3903
3904                         foreach (MethodBase candidate in candidates){
3905                                 if (candidate == method)
3906                                         continue;
3907
3908                                 //
3909                                 // If a normal method is applicable in the sense that it has the same
3910                                 // number of arguments, then the expanded params method is never applicable
3911                                 // so we debar the params method.
3912                                 //
3913                                 if (IsParamsMethodApplicable (ec, Arguments, candidate) &&
3914                                     IsApplicable (ec, ref Arguments, method))
3915                                         continue;
3916
3917                                 int x = BetterFunction (ec, Arguments, method, candidate,
3918                                                         chose_params_expanded, loc);
3919
3920                                 if (x != 1) {
3921                                         Report.Error (
3922                                                 121, loc,
3923                                                 "Ambiguous call when selecting function due to implicit casts");
3924                                         return null;
3925                                 }
3926                         }
3927
3928                         //
3929                         // And now check if the arguments are all compatible, perform conversions
3930                         // if necessary etc. and return if everything is all right
3931                         //
3932                         if (VerifyArgumentsCompat (ec, Arguments, argument_count, method,
3933                                                    chose_params_expanded, null, loc))
3934                                 return method;
3935                         else
3936                                 return null;
3937                 }
3938
3939                 public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
3940                         int argument_count,
3941                         MethodBase method,
3942                         bool chose_params_expanded,
3943                         Type delegate_type,
3944                         Location loc)
3945                 {
3946                         return (VerifyArgumentsCompat (ec, Arguments, argument_count,
3947                                 method, chose_params_expanded, delegate_type, loc, null));
3948                 }
3949
3950                 public static bool VerifyArgumentsCompat (EmitContext ec,
3951                                                           ArrayList Arguments,
3952                                                           int argument_count,
3953                                                           MethodBase method,
3954                                                           bool chose_params_expanded,
3955                                                           Type delegate_type,
3956                                                           Location loc,
3957                                                           string InvokingProperty)
3958                 {
3959                         ParameterData pd = GetParameterData (method);
3960                         int pd_count = pd.Count;
3961
3962                         for (int j = 0; j < argument_count; j++) {
3963                                 Argument a = (Argument) Arguments [j];
3964                                 Expression a_expr = a.Expr;
3965                                 Type parameter_type = pd.ParameterType(j);
3966
3967                                 if (parameter_type == null)
3968                                 {
3969                                         Error_WrongNumArguments(loc, (InvokingProperty == null)?((delegate_type == null)?FullMethodDesc (method):delegate_type.ToString ()):InvokingProperty, argument_count);
3970                                         return false;
3971                                 }
3972                                 if (pd.ParameterModifier (j) == Parameter.Modifier.PARAMS &&
3973                                 chose_params_expanded)
3974                                         parameter_type = TypeManager.TypeToCoreType (parameter_type.GetElementType ());
3975
3976                                 if (a.Type != parameter_type){
3977                                         Expression conv;
3978
3979                                         conv = ConvertImplicit (ec, a_expr, parameter_type, loc);
3980
3981                                         if (conv == null) {
3982                                                 if (!Location.IsNull (loc)) {
3983                                                         if (delegate_type == null)
3984                                                                 if (InvokingProperty == null)
3985                                                                         Report.Error (1502, loc,
3986                                                                                 "The best overloaded match for method '" +
3987                                                                                 FullMethodDesc (method) +
3988                                                                                 "' has some invalid arguments");
3989                                                                 else
3990                                                                         Report.Error (1502, loc,
3991                                                                                 "Property '" +
3992                                                                                 InvokingProperty +
3993                                                                                 "' has some invalid arguments");
3994                                                         else
3995                                                                 Report.Error (1594, loc,
3996                                                                               "Delegate '" + delegate_type.ToString () +
3997                                                                               "' has some invalid arguments.");
3998                                                         Report.Error (1503, loc,
3999                                                          "Argument " + (j+1) +
4000                                                          ": Cannot convert from '" + Argument.FullDesc (a)
4001                                                          + "' to '" + pd.ParameterDesc (j) + "'");
4002                                                 }
4003
4004                                                 return false;
4005                                         }
4006
4007                                         //
4008                                         // Update the argument with the implicit conversion
4009                                         //
4010                                         if (a_expr != conv)
4011                                                 a.Expr = conv;
4012                                 }
4013
4014                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
4015                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
4016                                 Parameter.Modifier p_mod = pd.ParameterModifier (j) &
4017                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
4018
4019
4020                                 if (a_mod != p_mod &&
4021                                     pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
4022                                         if (!Location.IsNull (loc)) {
4023                                                 Report.Error (1502, loc,
4024                                                        "The best overloaded match for method '" + FullMethodDesc (method)+
4025                                                        "' has some invalid arguments");
4026                                                 Report.Error (1503, loc,
4027                                                        "Argument " + (j+1) +
4028                                                        ": Cannot convert from '" + Argument.FullDesc (a)
4029                                                        + "' to '" + pd.ParameterDesc (j) + "'");
4030                                         }
4031
4032                                         return false;
4033                                 }
4034                         }
4035
4036                         return true;
4037                 }
4038
4039                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
4040                 {
4041                         this.is_left_hand = true;
4042                         return DoResolve (ec);
4043                 }
4044
4045                 public override Expression DoResolve (EmitContext ec)
4046                 {
4047                         //
4048                         // First, resolve the expression that is used to
4049                         // trigger the invocation
4050                         //
4051                         Expression expr_to_return = null;
4052
4053                         if (expr is BaseAccess)
4054                                 is_base = true;
4055
4056                         if ((ec.ReturnType != null) && (expr.ToString() == ec.BlockName)) {
4057                                 ec.InvokingOwnOverload = true;
4058                                 expr = expr.Resolve (ec, ResolveFlags.MethodGroup);
4059                                 ec.InvokingOwnOverload = false;
4060                         }
4061                         else
4062                         {
4063                                 ec.InvokingOwnOverload = false;
4064                                 expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
4065                         }
4066                         if (expr == null)
4067                                 return null;
4068
4069                         if (expr is Invocation) {
4070                                 // FIXME Calls which return an Array are not resolved (here or in the grammar)
4071                                 expr = expr.Resolve(ec);
4072                         }
4073
4074                         if (!(expr is MethodGroupExpr))
4075                         {
4076                                 Type expr_type = expr.Type;
4077
4078                                 if (expr_type != null)
4079                                 {
4080                                         bool IsDelegate = TypeManager.IsDelegateType (expr_type);
4081                                         if (IsDelegate)
4082                                                 return (new DelegateInvocation (
4083                                                         this.expr, Arguments, loc)).Resolve (ec);
4084                                 }
4085                         }
4086
4087                         //
4088                         // Next, evaluate all the expressions in the argument list
4089                         //
4090                         if (Arguments != null)
4091                         {
4092                                 foreach (Argument a in Arguments)
4093                                 {
4094                                         if ((a.ArgType == Argument.AType.NoArg) && (!(expr is MethodGroupExpr)))
4095                                                 Report.Error (999, "This item cannot have empty arguments");
4096
4097
4098                                         if (!a.Resolve (ec, loc))
4099                                                 return null;
4100                                 }
4101                         }
4102
4103                         if (expr is MethodGroupExpr)
4104                         {
4105                                 MethodGroupExpr mg = (MethodGroupExpr) expr;
4106                                 method = OverloadResolve (ec, mg, ref Arguments, loc);
4107
4108                                 if (method == null)
4109                                 {
4110                                         Error (30455,
4111                                                 "Could not find any applicable function to invoke for this argument list");
4112                                         return null;
4113                                 }
4114
4115                                 if ((method as MethodInfo) != null)
4116                                 {
4117                                         MethodInfo mi = method as MethodInfo;
4118                                         type = TypeManager.TypeToCoreType (mi.ReturnType);
4119                                         if (!mi.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null))
4120                                                 SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
4121                                 }
4122
4123                                 if ((method as ConstructorInfo) != null)
4124                                 {
4125                                         ConstructorInfo ci = method as ConstructorInfo;
4126                                         type = TypeManager.void_type;
4127                                         if (!ci.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null))
4128                                                 SimpleName.Error_ObjectRefRequired (ec, loc, ci.Name);
4129                                 }
4130
4131                                 if (type.IsPointer)
4132                                 {
4133                                         if (!ec.InUnsafe)
4134                                         {
4135                                                 UnsafeError (loc);
4136                                                 return null;
4137                                         }
4138                                 }
4139                                 eclass = ExprClass.Value;
4140                                 expr_to_return = this;
4141                         }
4142
4143                         if (expr is PropertyExpr)
4144                         {
4145                                 PropertyExpr pe = ((PropertyExpr) expr);
4146                                 pe.PropertyArgs = (ArrayList) Arguments.Clone();
4147                                 Arguments.Clear();
4148                                 Arguments = new ArrayList();
4149                                 MethodBase mi = pe.PropertyInfo.GetGetMethod(true);
4150
4151                                 if(VerifyArgumentsCompat (ec, pe.PropertyArgs,
4152                                         pe.PropertyArgs.Count, mi, false, null, loc, pe.Name))
4153                                 {
4154
4155                                         expr_to_return = pe.DoResolve (ec);
4156                                         expr_to_return.eclass = ExprClass.PropertyAccess;
4157                                 }
4158                                 else
4159                                 {
4160                                         throw new Exception("Error resolving Property Access expression\n" + pe.ToString());
4161                                 }
4162                         }
4163
4164                         if (expr is FieldExpr || expr is LocalVariableReference || expr is ParameterReference) {
4165                                 if (expr.Type.IsArray) {
4166                                         // If we are here, expr must be an ArrayAccess
4167                                         ArrayList idxs = new ArrayList();
4168                                         foreach (Argument a in Arguments)
4169                                         {
4170                                                 idxs.Add (a.Expr);
4171                                         }
4172                                         ElementAccess ea = new ElementAccess (expr, idxs, expr.Location);
4173                                         ArrayAccess aa = new ArrayAccess (ea, expr.Location);
4174                                         expr_to_return = aa.DoResolve(ec);
4175                                         expr_to_return.eclass = ExprClass.Variable;
4176                                 }
4177                                 else
4178                                 {
4179                                         // We can't resolve now, but we
4180                                         // have to try to access the array with a call
4181                                         // to LateIndexGet/Set in the runtime
4182                                         Expression lig_call_expr;
4183
4184                                         if (!is_left_hand)
4185                                                 lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexGet", Location.Null);
4186                                         else
4187                                                 lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexSet", Location.Null);
4188                                         Expression obj_type = Mono.MonoBASIC.Parser.DecomposeQI("System.Object", Location.Null);
4189                                         ArrayList adims = new ArrayList();
4190
4191                                         ArrayList ainit = new ArrayList();
4192                                         foreach (Argument a in Arguments)
4193                                                 ainit.Add ((Expression) a.Expr);
4194
4195                                         adims.Add ((Expression) new IntLiteral (Arguments.Count));
4196
4197                                         Expression oace = new ArrayCreation (obj_type, adims, "", ainit, Location.Null);
4198
4199                                         ArrayList args = new ArrayList();
4200                                         args.Add (new Argument(expr, Argument.AType.Expression));
4201                                         args.Add (new Argument(oace, Argument.AType.Expression));
4202                                         args.Add (new Argument(NullLiteral.Null, Argument.AType.Expression));
4203
4204                                         Expression lig_call = new Invocation (lig_call_expr, args, Location.Null);
4205                                         expr_to_return = lig_call.Resolve(ec);
4206                                         expr_to_return.eclass = ExprClass.Variable;
4207                                 }
4208                         }
4209
4210                         return expr_to_return;
4211                 }
4212
4213         static void Error_WrongNumArguments (Location loc, String name, int arg_count)
4214         {
4215             Report.Error (1501, loc, "No overload for method `" + name + "' takes `" +
4216                                       arg_count + "' arguments");
4217         }
4218
4219                 // <summary>
4220                 //   Emits the list of arguments as an array
4221                 // </summary>
4222                 static void EmitParams (EmitContext ec, int idx, ArrayList arguments)
4223                 {
4224                         ILGenerator ig = ec.ig;
4225                         int count = arguments.Count - idx;
4226                         Argument a = (Argument) arguments [idx];
4227                         Type t = a.Expr.Type;
4228                         string array_type = t.FullName + "[]";
4229                         LocalBuilder array;
4230
4231                         array = ig.DeclareLocal (TypeManager.LookupType (array_type));
4232                         IntConstant.EmitInt (ig, count);
4233                         ig.Emit (OpCodes.Newarr, TypeManager.TypeToCoreType (t));
4234                         ig.Emit (OpCodes.Stloc, array);
4235
4236                         int top = arguments.Count;
4237                         for (int j = idx; j < top; j++){
4238                                 a = (Argument) arguments [j];
4239
4240                                 ig.Emit (OpCodes.Ldloc, array);
4241                                 IntConstant.EmitInt (ig, j - idx);
4242                                 a.Emit (ec);
4243
4244                                 ArrayAccess.EmitStoreOpcode (ig, t);
4245                         }
4246                         ig.Emit (OpCodes.Ldloc, array);
4247                 }
4248
4249                 /// <summary>
4250                 ///   Emits a list of resolved Arguments that are in the arguments
4251                 ///   ArrayList.
4252                 ///
4253                 ///   The MethodBase argument might be null if the
4254                 ///   emission of the arguments is known not to contain
4255                 ///   a 'params' field (for example in constructors or other routines
4256                 ///   that keep their arguments in this structure)
4257                 /// </summary>
4258                 public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments)
4259                 {
4260                         ParameterData pd;
4261                         if (mb != null)
4262                                 pd = GetParameterData (mb);
4263                         else
4264                                 pd = null;
4265
4266                         //
4267                         // If we are calling a params method with no arguments, special case it
4268                         //
4269                         if (arguments == null){
4270                                 if (pd != null && pd.Count > 0 &&
4271                                     pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
4272                                         ILGenerator ig = ec.ig;
4273
4274                                         IntConstant.EmitInt (ig, 0);
4275                                         ig.Emit (OpCodes.Newarr, pd.ParameterType (0).GetElementType ());
4276                                 }
4277                                 return;
4278                         }
4279
4280                         int top = arguments.Count;
4281
4282                         for (int i = 0; i < top; i++){
4283                                 Argument a = (Argument) arguments [i];
4284
4285                                 if (pd != null){
4286                                         if (pd.ParameterModifier (i) == Parameter.Modifier.PARAMS){
4287                                                 //
4288                                                 // Special case if we are passing the same data as the
4289                                                 // params argument, do not put it in an array.
4290                                                 //
4291                                                 if (pd.ParameterType (i) == a.Type)
4292                                                         a.Emit (ec);
4293                                                 else
4294                                                         EmitParams (ec, i, arguments);
4295                                                 return;
4296                                         }
4297                                 }
4298
4299                                 a.Emit (ec);
4300                         }
4301
4302                         if (pd != null && pd.Count > top &&
4303                             pd.ParameterModifier (top) == Parameter.Modifier.PARAMS){
4304                                 ILGenerator ig = ec.ig;
4305
4306                                 IntConstant.EmitInt (ig, 0);
4307                                 ig.Emit (OpCodes.Newarr, pd.ParameterType (top).GetElementType ());
4308                         }
4309                 }
4310
4311                 /// <remarks>
4312                 ///   is_base tells whether we want to force the use of the 'call'
4313                 ///   opcode instead of using callvirt.  Call is required to call
4314                 ///   a specific method, while callvirt will always use the most
4315                 ///   recent method in the vtable.
4316                 ///
4317                 ///   is_static tells whether this is an invocation on a static method
4318                 ///
4319                 ///   instance_expr is an expression that represents the instance
4320                 ///   it must be non-null if is_static is false.
4321                 ///
4322                 ///   method is the method to invoke.
4323                 ///
4324                 ///   Arguments is the list of arguments to pass to the method or constructor.
4325                 /// </remarks>
4326                 public static void EmitCall (EmitContext ec, bool is_base,
4327                                              bool is_static, Expression instance_expr,
4328                                              MethodBase method, ArrayList Arguments, Location loc)
4329                 {
4330                         EmitCall (ec, is_base, is_static, instance_expr, method, Arguments, null, loc);
4331                 }
4332
4333                 public static void EmitCall (EmitContext ec, bool is_base,
4334                         bool is_static, Expression instance_expr,
4335                         MethodBase method, ArrayList Arguments, ArrayList prop_args, Location loc)
4336                 {
4337                         ILGenerator ig = ec.ig;
4338                         bool struct_call = false;
4339
4340                         Type decl_type = method.DeclaringType;
4341
4342                         if (!RootContext.StdLib)
4343                         {
4344                                 // Replace any calls to the system's System.Array type with calls to
4345                                 // the newly created one.
4346                                 if (method == TypeManager.system_int_array_get_length)
4347                                         method = TypeManager.int_array_get_length;
4348                                 else if (method == TypeManager.system_int_array_get_rank)
4349                                         method = TypeManager.int_array_get_rank;
4350                                 else if (method == TypeManager.system_object_array_clone)
4351                                         method = TypeManager.object_array_clone;
4352                                 else if (method == TypeManager.system_int_array_get_length_int)
4353                                         method = TypeManager.int_array_get_length_int;
4354                                 else if (method == TypeManager.system_int_array_get_lower_bound_int)
4355                                         method = TypeManager.int_array_get_lower_bound_int;
4356                                 else if (method == TypeManager.system_int_array_get_upper_bound_int)
4357                                         method = TypeManager.int_array_get_upper_bound_int;
4358                                 else if (method == TypeManager.system_void_array_copyto_array_int)
4359                                         method = TypeManager.void_array_copyto_array_int;
4360                         }
4361
4362                         //
4363                         // This checks the 'ConditionalAttribute' on the method, and the
4364                         // ObsoleteAttribute
4365                         //
4366                         TypeManager.MethodFlags flags = TypeManager.GetMethodFlags (method, loc);
4367                         if ((flags & TypeManager.MethodFlags.IsObsoleteError) != 0)
4368                                 return;
4369                         if ((flags & TypeManager.MethodFlags.ShouldIgnore) != 0)
4370                                 return;
4371
4372                         if (!is_static)
4373                         {
4374                                 if (decl_type.IsValueType)
4375                                         struct_call = true;
4376                                 //
4377                                 // If this is ourselves, push "this"
4378                                 //
4379                                 if (instance_expr == null)
4380                                 {
4381                                         ig.Emit (OpCodes.Ldarg_0);
4382                                 }
4383                                 else
4384                                 {
4385                                         //
4386                                         // Push the instance expression
4387                                         //
4388                                         if (instance_expr.Type.IsValueType)
4389                                         {
4390                                                 //
4391                                                 // Special case: calls to a function declared in a
4392                                                 // reference-type with a value-type argument need
4393                                                 // to have their value boxed.
4394
4395                                                 struct_call = true;
4396                                                 if (decl_type.IsValueType)
4397                                                 {
4398                                                         //
4399                                                         // If the expression implements IMemoryLocation, then
4400                                                         // we can optimize and use AddressOf on the
4401                                                         // return.
4402                                                         //
4403                                                         // If not we have to use some temporary storage for
4404                                                         // it.
4405                                                         if (instance_expr is IMemoryLocation)
4406                                                         {
4407                                                                 ((IMemoryLocation)instance_expr).
4408                                                                         AddressOf (ec, AddressOp.LoadStore);
4409                                                         }
4410                                                         else
4411                                                         {
4412                                                                 Type t = instance_expr.Type;
4413
4414                                                                 instance_expr.Emit (ec);
4415                                                                 LocalBuilder temp = ig.DeclareLocal (t);
4416                                                                 ig.Emit (OpCodes.Stloc, temp);
4417                                                                 ig.Emit (OpCodes.Ldloca, temp);
4418                                                         }
4419                                                 }
4420                                                 else
4421                                                 {
4422                                                         instance_expr.Emit (ec);
4423                                                         ig.Emit (OpCodes.Box, instance_expr.Type);
4424                                                 }
4425                                         }
4426                                         else
4427                                                 instance_expr.Emit (ec);
4428                                 }
4429                         }
4430
4431                         if (prop_args != null && prop_args.Count > 0)
4432                         {
4433                                 if (Arguments == null)
4434                                         Arguments = new ArrayList();
4435
4436                                 for (int i = prop_args.Count-1; i >=0 ; i--)
4437                                 {
4438                                         Arguments.Insert (0,prop_args[i]);
4439                                 }
4440
4441                         }
4442
4443                         EmitArguments (ec, method, Arguments);
4444
4445                         if (is_static || struct_call || is_base)
4446                         {
4447                                 if (method is MethodInfo)
4448                                 {
4449                                         ig.Emit (OpCodes.Call, (MethodInfo) method);
4450                                 }
4451                                 else
4452                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4453                         }
4454                         else
4455                         {
4456                                 if (method is MethodInfo)
4457                                         ig.Emit (OpCodes.Callvirt, (MethodInfo) method);
4458                                 else
4459                                         ig.Emit (OpCodes.Callvirt, (ConstructorInfo) method);
4460                         }
4461                 }
4462
4463                 static void EmitPropertyArgs (EmitContext ec, ArrayList prop_args)
4464                 {
4465                         int top = prop_args.Count;
4466
4467                         for (int i = 0; i < top; i++)
4468                         {
4469                                 Argument a = (Argument) prop_args [i];
4470                                 a.Emit (ec);
4471                         }
4472                 }
4473
4474                 public override void Emit (EmitContext ec)
4475                 {
4476                         MethodGroupExpr mg = (MethodGroupExpr) this.expr;
4477
4478                         EmitCall (
4479                                 ec, is_base, method.IsStatic, mg.InstanceExpression, method, Arguments, loc);
4480                 }
4481
4482                 public override void EmitStatement (EmitContext ec)
4483                 {
4484                         Emit (ec);
4485
4486                         //
4487                         // Pop the return value if there is one
4488                         //
4489                         if (method is MethodInfo){
4490                                 Type ret = ((MethodInfo)method).ReturnType;
4491                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
4492                                         ec.ig.Emit (OpCodes.Pop);
4493                         }
4494                 }
4495         }
4496
4497         //
4498         // This class is used to "disable" the code generation for the
4499         // temporary variable when initializing value types.
4500         //
4501         class EmptyAddressOf : EmptyExpression, IMemoryLocation {
4502                 public void AddressOf (EmitContext ec, AddressOp Mode)
4503                 {
4504                         // nothing
4505                 }
4506         }
4507
4508         /// <summary>
4509         ///    Implements the new expression
4510         /// </summary>
4511         public class New : ExpressionStatement {
4512                 public readonly ArrayList Arguments;
4513                 public readonly Expression RequestedType;
4514
4515                 MethodBase method = null;
4516
4517                 //
4518                 // If set, the new expression is for a value_target, and
4519                 // we will not leave anything on the stack.
4520                 //
4521                 Expression value_target;
4522                 bool value_target_set = false;
4523                 public bool isDelegate = false;
4524
4525                 public New (Expression requested_type, ArrayList arguments, Location l)
4526                 {
4527                         RequestedType = requested_type;
4528                         Arguments = arguments;
4529                         loc = l;
4530                 }
4531
4532                 public Expression ValueTypeVariable {
4533                         get {
4534                                 return value_target;
4535                         }
4536
4537                         set {
4538                                 value_target = value;
4539                                 value_target_set = true;
4540                         }
4541                 }
4542
4543                 //
4544                 // This function is used to disable the following code sequence for
4545                 // value type initialization:
4546                 //
4547                 // AddressOf (temporary)
4548                 // Construct/Init
4549                 // LoadTemporary
4550                 //
4551                 // Instead the provide will have provided us with the address on the
4552                 // stack to store the results.
4553                 //
4554                 static Expression MyEmptyExpression;
4555
4556                 public void DisableTemporaryValueType ()
4557                 {
4558                         if (MyEmptyExpression == null)
4559                                 MyEmptyExpression = new EmptyAddressOf ();
4560
4561                         //
4562                         // To enable this, look into:
4563                         // test-34 and test-89 and self bootstrapping.
4564                         //
4565                         // For instance, we can avoid a copy by using 'newobj'
4566                         // instead of Call + Push-temp on value types.
4567 //                      value_target = MyEmptyExpression;
4568                 }
4569
4570                 public override Expression DoResolve (EmitContext ec)
4571                 {
4572                         if (this.isDelegate) {
4573                                 // if its a delegate resolve the type of RequestedType first
4574                                 Expression dtype = RequestedType.Resolve(ec);
4575                                 string ts = (dtype.Type.ToString()).Replace ('+','.');
4576                                 dtype = Mono.MonoBASIC.Parser.DecomposeQI (ts, Location.Null);
4577
4578                                 type = ec.DeclSpace.ResolveType (dtype, false, loc);
4579                         }
4580                         else
4581                                 type = ec.DeclSpace.ResolveType (RequestedType, false, loc);
4582
4583                         if (type == null)
4584                                 return null;
4585
4586                         bool IsDelegate = TypeManager.IsDelegateType (type);
4587
4588                         if (IsDelegate)
4589                                 return (new NewDelegate (type, Arguments, loc)).Resolve (ec);
4590
4591                         if (type.IsInterface || type.IsAbstract){
4592                                 Error (
4593                                         30376, "It is not possible to create instances of Interfaces " +
4594                                         "or classes marked as MustInherit");
4595                                 return null;
4596                         }
4597
4598                         bool is_struct = false;
4599                         is_struct = type.IsValueType;
4600                         eclass = ExprClass.Value;
4601
4602                         //
4603                         // SRE returns a match for .ctor () on structs (the object constructor),
4604                         // so we have to manually ignore it.
4605                         //
4606                         if (is_struct && Arguments == null)
4607                                 return this;
4608
4609                         Expression ml;
4610                         ml = MemberLookupFinal (ec, type, ".ctor",
4611                                                 MemberTypes.Constructor,
4612                                                 AllBindingFlags | BindingFlags.Public, loc);
4613
4614                         if (ml == null)
4615                                 return null;
4616
4617                         if (! (ml is MethodGroupExpr)){
4618                                 if (!is_struct){
4619                                         ml.Error118 ("method group");
4620                                         return null;
4621                                 }
4622                         }
4623
4624                         if (ml != null) {
4625                                 if (Arguments != null){
4626                                         foreach (Argument a in Arguments){
4627                                                 if (!a.Resolve (ec, loc))
4628                                                         return null;
4629                                         }
4630                                 }
4631
4632                                 method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml,
4633                                                                      Arguments, loc);
4634
4635                         }
4636
4637                         if (method == null) {
4638                                 if (!is_struct || Arguments.Count > 0) {
4639                                         Error (1501,
4640                                                "New invocation: Can not find a constructor for " +
4641                                                "this argument list");
4642                                         return null;
4643                                 }
4644                         }
4645                         return this;
4646                 }
4647
4648                 //
4649                 // This DoEmit can be invoked in two contexts:
4650                 //    * As a mechanism that will leave a value on the stack (new object)
4651                 //    * As one that wont (init struct)
4652                 //
4653                 // You can control whether a value is required on the stack by passing
4654                 // need_value_on_stack.  The code *might* leave a value on the stack
4655                 // so it must be popped manually
4656                 //
4657                 // If we are dealing with a ValueType, we have a few
4658                 // situations to deal with:
4659                 //
4660                 //    * The target is a ValueType, and we have been provided
4661                 //      the instance (this is easy, we are being assigned).
4662                 //
4663                 //    * The target of New is being passed as an argument,
4664                 //      to a boxing operation or a function that takes a
4665                 //      ValueType.
4666                 //
4667                 //      In this case, we need to create a temporary variable
4668                 //      that is the argument of New.
4669                 //
4670                 // Returns whether a value is left on the stack
4671                 //
4672                 bool DoEmit (EmitContext ec, bool need_value_on_stack)
4673                 {
4674                         bool is_value_type = type.IsValueType;
4675                         ILGenerator ig = ec.ig;
4676
4677                         if (is_value_type){
4678                                 IMemoryLocation ml;
4679
4680                                 // Allow DoEmit() to be called multiple times.
4681                                 // We need to create a new LocalTemporary each time since
4682                                 // you can't share LocalBuilders among ILGeneators.
4683                                 if (!value_target_set)
4684                                         value_target = new LocalTemporary (ec, type);
4685
4686                                 ml = (IMemoryLocation) value_target;
4687                                 ml.AddressOf (ec, AddressOp.Store);
4688                         }
4689
4690                         if (method != null)
4691                                 Invocation.EmitArguments (ec, method, Arguments);
4692
4693                         if (is_value_type){
4694                                 if (method == null)
4695                                         ig.Emit (OpCodes.Initobj, type);
4696                                 else
4697                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4698                                 if (need_value_on_stack){
4699                                         value_target.Emit (ec);
4700                                         return true;
4701                                 }
4702                                 return false;
4703                         } else {
4704                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) method);
4705                                 return true;
4706                         }
4707                 }
4708
4709                 public override void Emit (EmitContext ec)
4710                 {
4711                         DoEmit (ec, true);
4712                 }
4713
4714                 public override void EmitStatement (EmitContext ec)
4715                 {
4716                         if (DoEmit (ec, false))
4717                                 ec.ig.Emit (OpCodes.Pop);
4718                 }
4719         }
4720
4721         /// <summary>
4722         ///   14.5.10.2: Represents an array creation expression.
4723         /// </summary>
4724         ///
4725         /// <remarks>
4726         ///   There are two possible scenarios here: one is an array creation
4727         ///   expression that specifies the dimensions and optionally the
4728         ///   initialization data and the other which does not need dimensions
4729         ///   specified but where initialization data is mandatory.
4730         /// </remarks>
4731         public class ArrayCreation : ExpressionStatement {
4732                 Expression requested_base_type;
4733                 ArrayList initializers;
4734
4735                 //
4736                 // The list of Argument types.
4737                 // This is used to construct the 'newarray' or constructor signature
4738                 //
4739                 ArrayList arguments;
4740
4741                 //
4742                 // Method used to create the array object.
4743                 //
4744                 MethodBase new_method = null;
4745
4746                 Type array_element_type;
4747                 Type underlying_type;
4748                 bool is_one_dimensional = false;
4749                 bool is_builtin_type = false;
4750                 bool expect_initializers = false;
4751                 int num_arguments = 0;
4752                 int dimensions = 0;
4753                 string rank;
4754
4755                 ArrayList array_data;
4756
4757                 Hashtable bounds;
4758
4759                 //
4760                 // The number of array initializers that we can handle
4761                 // via the InitializeArray method - through EmitStaticInitializers
4762                 //
4763                 int num_automatic_initializers;
4764
4765                 public ArrayCreation (Expression requested_base_type, ArrayList exprs, string rank, ArrayList initializers, Location l)
4766                 {
4767                         this.requested_base_type = requested_base_type;
4768                         this.initializers = initializers;
4769                         this.rank = rank;
4770                         loc = l;
4771
4772                         arguments = new ArrayList ();
4773
4774                         foreach (Expression e in exprs) {
4775                                 arguments.Add (new Argument (e, Argument.AType.Expression));
4776                                 num_arguments++;
4777                         }
4778                 }
4779
4780                 public ArrayCreation (Expression requested_base_type, string rank, ArrayList initializers, Location l)
4781                 {
4782                         this.requested_base_type = requested_base_type;
4783                         this.initializers = initializers;
4784                         this.rank = rank;
4785                         loc = l;
4786
4787                         //this.rank = rank.Substring (0, rank.LastIndexOf ("["));
4788                         //
4789                         //string tmp = rank.Substring (rank.LastIndexOf ("["));
4790                         //
4791                         //dimensions = tmp.Length - 1;
4792                         expect_initializers = true;
4793                 }
4794
4795                 public Expression FormArrayType (Expression base_type, int idx_count, string rank)
4796                 {
4797                         StringBuilder sb = new StringBuilder (rank);
4798
4799                         sb.Append ("[");
4800                         for (int i = 1; i < idx_count; i++)
4801                                 sb.Append (",");
4802
4803                         sb.Append ("]");
4804
4805                         return new ComposedCast (base_type, sb.ToString (), loc);
4806                 }
4807
4808                 void Error_IncorrectArrayInitializer ()
4809                 {
4810                         Error (30567, "Incorrectly structured array initializer");
4811                 }
4812
4813                 public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
4814                 {
4815                         if (specified_dims) {
4816                                 Argument a = (Argument) arguments [idx];
4817
4818                                 if (!a.Resolve (ec, loc))
4819                                         return false;
4820
4821                                 if (!(a.Expr is Constant)) {
4822                                         Error (150, "A constant value is expected");
4823                                         return false;
4824                                 }
4825
4826                                 int value = (int) ((Constant) a.Expr).GetValue ();
4827
4828                                 if (value != probe.Count) {
4829                                         Error_IncorrectArrayInitializer ();
4830                                         return false;
4831                                 }
4832
4833                                 bounds [idx] = value;
4834                         }
4835
4836                         int child_bounds = -1;
4837                         foreach (object o in probe) {
4838                                 if (o is ArrayList) {
4839                                         int current_bounds = ((ArrayList) o).Count;
4840
4841                                         if (child_bounds == -1)
4842                                                 child_bounds = current_bounds;
4843
4844                                         else if (child_bounds != current_bounds){
4845                                                 Error_IncorrectArrayInitializer ();
4846                                                 return false;
4847                                         }
4848                                         bool ret = CheckIndices (ec, (ArrayList) o, idx + 1, specified_dims);
4849                                         if (!ret)
4850                                                 return false;
4851                                 } else {
4852                                         if (child_bounds != -1){
4853                                                 Error_IncorrectArrayInitializer ();
4854                                                 return false;
4855                                         }
4856
4857                                         Expression tmp = (Expression) o;
4858                                         tmp = tmp.Resolve (ec);
4859                                         if (tmp == null)
4860                                                 continue;
4861
4862                                         // Console.WriteLine ("I got: " + tmp);
4863                                         // Handle initialization from vars, fields etc.
4864
4865                                         Expression conv = ConvertImplicitRequired (
4866                                                 ec, tmp, underlying_type, loc);
4867
4868                                         if (conv == null)
4869                                                 return false;
4870
4871                                         if (conv is StringConstant)
4872                                                 array_data.Add (conv);
4873                                         else if (conv is Constant) {
4874                                                 array_data.Add (conv);
4875                                                 num_automatic_initializers++;
4876                                         } else
4877                                                 array_data.Add (conv);
4878                                 }
4879                         }
4880
4881                         return true;
4882                 }
4883
4884                 public void UpdateIndices (EmitContext ec)
4885                 {
4886                         int i = 0;
4887                         for (ArrayList probe = initializers; probe != null;) {
4888                                 if (probe.Count > 0 && probe [0] is ArrayList) {
4889                                         Expression e = new IntConstant (probe.Count);
4890                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4891
4892                                         bounds [i++] =  probe.Count;
4893
4894                                         probe = (ArrayList) probe [0];
4895
4896                                 } else {
4897                                         Expression e = new IntConstant (probe.Count);
4898                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4899
4900                                         bounds [i++] = probe.Count;
4901                                         probe = null;
4902                                 }
4903                         }
4904
4905                 }
4906
4907                 public bool ValidateInitializers (EmitContext ec, Type array_type)
4908                 {
4909                         if (initializers == null) {
4910                                 if (expect_initializers)
4911                                         return false;
4912                                 else
4913                                         return true;
4914                         }
4915
4916                         if (underlying_type == null)
4917                                 return false;
4918
4919                         //
4920                         // We use this to store all the date values in the order in which we
4921                         // will need to store them in the byte blob later
4922                         //
4923                         array_data = new ArrayList ();
4924                         bounds = new Hashtable ();
4925
4926                         bool ret;
4927
4928                         if (arguments != null) {
4929                                 ret = CheckIndices (ec, initializers, 0, true);
4930                                 return ret;
4931                         } else {
4932                                 arguments = new ArrayList ();
4933
4934                                 ret = CheckIndices (ec, initializers, 0, false);
4935
4936                                 if (!ret)
4937                                         return false;
4938
4939                                 UpdateIndices (ec);
4940
4941                                 if (arguments.Count != dimensions) {
4942                                         Error_IncorrectArrayInitializer ();
4943                                         return false;
4944                                 }
4945
4946                                 return ret;
4947                         }
4948                 }
4949
4950                 void Error_NegativeArrayIndex ()
4951                 {
4952                         Error (284, "Can not create array with a negative size");
4953                 }
4954
4955                 //
4956                 // Converts 'source' to an int, uint, long or ulong.
4957                 //
4958                 Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
4959                 {
4960                         Expression target;
4961
4962                         bool old_checked = ec.CheckState;
4963                         ec.CheckState = true;
4964
4965                         target = ConvertImplicit (ec, source, TypeManager.int32_type, loc);
4966                         if (target == null){
4967                                 target = ConvertImplicit (ec, source, TypeManager.uint32_type, loc);
4968                                 if (target == null){
4969                                         target = ConvertImplicit (ec, source, TypeManager.int64_type, loc);
4970                                         if (target == null){
4971                                                 target = ConvertImplicit (ec, source, TypeManager.uint64_type, loc);
4972                                                 if (target == null)
4973                                                         Expression.Error_CannotConvertImplicit (loc, source.Type, TypeManager.int32_type);
4974                                         }
4975                                 }
4976                         }
4977                         ec.CheckState = old_checked;
4978
4979                         //
4980                         // Only positive constants are allowed at compile time
4981                         //
4982                         if (target is Constant){
4983                                 if (target is IntConstant){
4984                                         if (((IntConstant) target).Value < 0){
4985                                                 Error_NegativeArrayIndex ();
4986                                                 return null;
4987                                         }
4988                                 }
4989
4990                                 if (target is LongConstant){
4991                                         if (((LongConstant) target).Value < 0){
4992                                                 Error_NegativeArrayIndex ();
4993                                                 return null;
4994                                         }
4995                                 }
4996
4997                         }
4998
4999                         return target;
5000                 }
5001
5002                 //
5003                 // Creates the type of the array
5004                 //
5005                 bool LookupType (EmitContext ec)
5006                 {
5007                         StringBuilder array_qualifier = new StringBuilder (rank);
5008
5009                         //
5010                         // 'In the first form allocates an array instace of the type that results
5011                         // from deleting each of the individual expression from the expression list'
5012                         //
5013                         if (num_arguments > 0) {
5014                                 array_qualifier.Append ("[");
5015                                 for (int i = num_arguments-1; i > 0; i--)
5016                                         array_qualifier.Append (",");
5017                                 array_qualifier.Append ("]");
5018                         }
5019
5020                         //
5021                         // Lookup the type
5022                         //
5023                         Expression array_type_expr;
5024                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
5025                         string sss = array_qualifier.ToString ();
5026                         type = ec.DeclSpace.ResolveType (array_type_expr, false, loc);
5027
5028                         if (type == null)
5029                                 return false;
5030
5031                         underlying_type = type;
5032                         if (underlying_type.IsArray)
5033                                 underlying_type = TypeManager.TypeToCoreType (underlying_type.GetElementType ());
5034                         dimensions = type.GetArrayRank ();
5035
5036                         return true;
5037                 }
5038
5039                 public override Expression DoResolve (EmitContext ec)
5040                 {
5041                         int arg_count;
5042
5043                         if (!LookupType (ec))
5044                                 return null;
5045
5046                         //
5047                         // First step is to validate the initializers and fill
5048                         // in any missing bits
5049                         //
5050                         if (!ValidateInitializers (ec, type))
5051                                 return null;
5052
5053                         if (arguments == null)
5054                                 arg_count = 0;
5055                         else {
5056                                 arg_count = arguments.Count;
5057                                 foreach (Argument a in arguments){
5058                                         if (!a.Resolve (ec, loc))
5059                                                 return null;
5060
5061                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
5062                                         if (real_arg == null)
5063                                                 return null;
5064
5065                                         a.Expr = real_arg;
5066                                 }
5067                         }
5068
5069                         array_element_type = TypeManager.TypeToCoreType (type.GetElementType ());
5070
5071                         if (arg_count == 1) {
5072                                 is_one_dimensional = true;
5073                                 eclass = ExprClass.Value;
5074                                 return this;
5075                         }
5076
5077                         is_builtin_type = TypeManager.IsBuiltinType (type);
5078
5079                         if (is_builtin_type) {
5080                                 Expression ml;
5081
5082                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
5083                                                    AllBindingFlags, loc);
5084
5085                                 if (!(ml is MethodGroupExpr)) {
5086                                         ml.Error118 ("method group");
5087                                         return null;
5088                                 }
5089
5090                                 if (ml == null) {
5091                                         Error (-6, "New invocation: Can not find a constructor for " +
5092                                                       "this argument list");
5093                                         return null;
5094                                 }
5095
5096                                 new_method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml, arguments, loc);
5097
5098                                 if (new_method == null) {
5099                                         Error (-6, "New invocation: Can not find a constructor for " +
5100                                                       "this argument list");
5101                                         return null;
5102                                 }
5103
5104                                 eclass = ExprClass.Value;
5105                                 return this;
5106                         } else {
5107                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
5108                                 ArrayList args = new ArrayList ();
5109
5110                                 if (arguments != null) {
5111                                         for (int i = 0; i < arg_count; i++)
5112                                                 args.Add (TypeManager.int32_type);
5113                                 }
5114
5115                                 Type [] arg_types = null;
5116
5117                                 if (args.Count > 0)
5118                                         arg_types = new Type [args.Count];
5119
5120                                 args.CopyTo (arg_types, 0);
5121
5122                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
5123                                                             arg_types);
5124
5125                                 if (new_method == null) {
5126                                         Error (-6, "New invocation: Can not find a constructor for " +
5127                                                       "this argument list");
5128                                         return null;
5129                                 }
5130
5131                                 eclass = ExprClass.Value;
5132                                 return this;
5133                         }
5134                 }
5135
5136                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
5137                 {
5138                         int factor;
5139                         byte [] data;
5140                         byte [] element;
5141                         int count = array_data.Count;
5142
5143                         if (underlying_type.IsEnum)
5144                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
5145
5146                         factor = GetTypeSize (underlying_type);
5147                         if (factor == 0)
5148                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
5149
5150                         data = new byte [(count * factor + 4) & ~3];
5151                         int idx = 0;
5152
5153                         for (int i = 0; i < count; ++i) {
5154                                 object v = array_data [i];
5155
5156                                 if (v is EnumConstant)
5157                                         v = ((EnumConstant) v).Child;
5158
5159                                 if (v is Constant && !(v is StringConstant))
5160                                         v = ((Constant) v).GetValue ();
5161                                 else {
5162                                         idx += factor;
5163                                         continue;
5164                                 }
5165
5166                                 if (underlying_type == TypeManager.int64_type){
5167                                         if (!(v is Expression)){
5168                                                 long val = (long) v;
5169
5170                                                 for (int j = 0; j < factor; ++j) {
5171                                                         data [idx + j] = (byte) (val & 0xFF);
5172                                                         val = (val >> 8);
5173                                                 }
5174                                         }
5175                                 } else if (underlying_type == TypeManager.uint64_type){
5176                                         if (!(v is Expression)){
5177                                                 ulong val = (ulong) v;
5178
5179                                                 for (int j = 0; j < factor; ++j) {
5180                                                         data [idx + j] = (byte) (val & 0xFF);
5181                                                         val = (val >> 8);
5182                                                 }
5183                                         }
5184                                 } else if (underlying_type == TypeManager.float_type) {
5185                                         if (!(v is Expression)){
5186                                                 element = BitConverter.GetBytes ((float) v);
5187
5188                                                 for (int j = 0; j < factor; ++j)
5189                                                         data [idx + j] = element [j];
5190                                         }
5191                                 } else if (underlying_type == TypeManager.double_type) {
5192                                         if (!(v is Expression)){
5193                                                 element = BitConverter.GetBytes ((double) v);
5194
5195                                                 for (int j = 0; j < factor; ++j)
5196                                                         data [idx + j] = element [j];
5197                                         }
5198                                 } else if (underlying_type == TypeManager.char_type){
5199                                         if (!(v is Expression)){
5200                                                 int val = (int) ((char) v);
5201
5202                                                 data [idx] = (byte) (val & 0xff);
5203                                                 data [idx+1] = (byte) (val >> 8);
5204                                         }
5205                                 } else if (underlying_type == TypeManager.short_type){
5206                                         if (!(v is Expression)){
5207                                                 int val = (int) ((short) v);
5208
5209                                                 data [idx] = (byte) (val & 0xff);
5210                                                 data [idx+1] = (byte) (val >> 8);
5211                                         }
5212                                 } else if (underlying_type == TypeManager.ushort_type){
5213                                         if (!(v is Expression)){
5214                                                 int val = (int) ((ushort) v);
5215
5216                                                 data [idx] = (byte) (val & 0xff);
5217                                                 data [idx+1] = (byte) (val >> 8);
5218                                         }
5219                                 } else if (underlying_type == TypeManager.int32_type) {
5220                                         if (!(v is Expression)){
5221                                                 int val = (int) v;
5222
5223                                                 data [idx]   = (byte) (val & 0xff);
5224                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
5225                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
5226                                                 data [idx+3] = (byte) (val >> 24);
5227                                         }
5228                                 } else if (underlying_type == TypeManager.uint32_type) {
5229                                         if (!(v is Expression)){
5230                                                 uint val = (uint) v;
5231
5232                                                 data [idx]   = (byte) (val & 0xff);
5233                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
5234                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
5235                                                 data [idx+3] = (byte) (val >> 24);
5236                                         }
5237                                 } else if (underlying_type == TypeManager.sbyte_type) {
5238                                         if (!(v is Expression)){
5239                                                 sbyte val = (sbyte) v;
5240                                                 data [idx] = (byte) val;
5241                                         }
5242                                 } else if (underlying_type == TypeManager.byte_type) {
5243                                         if (!(v is Expression)){
5244                                                 byte val = (byte) v;
5245                                                 data [idx] = (byte) val;
5246                                         }
5247                                 } else if (underlying_type == TypeManager.bool_type) {
5248                                         if (!(v is Expression)){
5249                                                 bool val = (bool) v;
5250                                                 data [idx] = (byte) (val ? 1 : 0);
5251                                         }
5252                                 } else if (underlying_type == TypeManager.decimal_type){
5253                                         if (!(v is Expression)){
5254                                                 int [] bits = Decimal.GetBits ((decimal) v);
5255                                                 int p = idx;
5256
5257                                                 for (int j = 0; j < 4; j++){
5258                                                         data [p++] = (byte) (bits [j] & 0xff);
5259                                                         data [p++] = (byte) ((bits [j] >> 8) & 0xff);
5260                                                         data [p++] = (byte) ((bits [j] >> 16) & 0xff);
5261                                                         data [p++] = (byte) (bits [j] >> 24);
5262                                                 }
5263                                         }
5264                                 } else
5265                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
5266
5267                                 idx += factor;
5268                         }
5269
5270                         return data;
5271                 }
5272
5273                 //
5274                 // Emits the initializers for the array
5275                 //
5276                 void EmitStaticInitializers (EmitContext ec, bool is_expression)
5277                 {
5278                         //
5279                         // First, the static data
5280                         //
5281                         FieldBuilder fb;
5282                         ILGenerator ig = ec.ig;
5283
5284                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
5285
5286                         fb = RootContext.MakeStaticData (data);
5287
5288                         if (is_expression)
5289                                 ig.Emit (OpCodes.Dup);
5290                         ig.Emit (OpCodes.Ldtoken, fb);
5291                         ig.Emit (OpCodes.Call,
5292                                  TypeManager.void_initializearray_array_fieldhandle);
5293                 }
5294
5295                 //
5296                 // Emits pieces of the array that can not be computed at compile
5297                 // time (variables and string locations).
5298                 //
5299                 // This always expect the top value on the stack to be the array
5300                 //
5301                 void EmitDynamicInitializers (EmitContext ec, bool is_expression)
5302                 {
5303                         ILGenerator ig = ec.ig;
5304                         int dims = bounds.Count;
5305                         int [] current_pos = new int [dims];
5306                         int top = array_data.Count;
5307                         LocalBuilder temp = ig.DeclareLocal (type);
5308
5309                         ig.Emit (OpCodes.Stloc, temp);
5310
5311                         MethodInfo set = null;
5312
5313                         if (dims != 1){
5314                                 Type [] args;
5315                                 ModuleBuilder mb = null;
5316                                 mb = CodeGen.ModuleBuilder;
5317                                 args = new Type [dims + 1];
5318
5319                                 int j;
5320                                 for (j = 0; j < dims; j++)
5321                                         args [j] = TypeManager.int32_type;
5322
5323                                 args [j] = array_element_type;
5324
5325                                 set = mb.GetArrayMethod (
5326                                         type, "Set",
5327                                         CallingConventions.HasThis | CallingConventions.Standard,
5328                                         TypeManager.void_type, args);
5329                         }
5330
5331                         for (int i = 0; i < top; i++){
5332
5333                                 Expression e = null;
5334
5335                                 if (array_data [i] is Expression)
5336                                         e = (Expression) array_data [i];
5337
5338                                 if (e != null) {
5339                                         //
5340                                         // Basically we do this for string literals and
5341                                         // other non-literal expressions
5342                                         //
5343                                         if (e is StringConstant || !(e is Constant) ||
5344                                             num_automatic_initializers <= 2) {
5345                                                 Type etype = e.Type;
5346
5347                                                 ig.Emit (OpCodes.Ldloc, temp);
5348
5349                                                 for (int idx = 0; idx < dims; idx++)
5350                                                         IntConstant.EmitInt (ig, current_pos [idx]);
5351
5352                                                 //
5353                                                 // If we are dealing with a struct, get the
5354                                                 // address of it, so we can store it.
5355                                                 //
5356                                                 if ((dims == 1) &&
5357                                                     etype.IsSubclassOf (TypeManager.value_type) &&
5358                                                     (!TypeManager.IsBuiltinType (etype) ||
5359                                                      etype == TypeManager.decimal_type)) {
5360                                                         if (e is New){
5361                                                                 New n = (New) e;
5362
5363                                                                 //
5364                                                                 // Let new know that we are providing
5365                                                                 // the address where to store the results
5366                                                                 //
5367                                                                 n.DisableTemporaryValueType ();
5368                                                         }
5369
5370                                                         ig.Emit (OpCodes.Ldelema, etype);
5371                                                 }
5372
5373                                                 e.Emit (ec);
5374
5375                                                 if (dims == 1)
5376                                                         ArrayAccess.EmitStoreOpcode (ig, array_element_type);
5377                                                 else
5378                                                         ig.Emit (OpCodes.Call, set);
5379                                         }
5380                                 }
5381
5382                                 //
5383                                 // Advance counter
5384                                 //
5385                                 for (int j = dims - 1; j >= 0; j--){
5386                                         current_pos [j]++;
5387                                         if (current_pos [j] < (int) bounds [j])
5388                                                 break;
5389                                         current_pos [j] = 0;
5390                                 }
5391                         }
5392
5393                         if (is_expression)
5394                                 ig.Emit (OpCodes.Ldloc, temp);
5395                 }
5396
5397                 void EmitArrayArguments (EmitContext ec)
5398                 {
5399                         ILGenerator ig = ec.ig;
5400
5401                         foreach (Argument a in arguments) {
5402                                 Type atype = a.Type;
5403                                 a.Emit (ec);
5404
5405                                 if (atype == TypeManager.uint64_type)
5406                                         ig.Emit (OpCodes.Conv_Ovf_U4);
5407                                 else if (atype == TypeManager.int64_type)
5408                                         ig.Emit (OpCodes.Conv_Ovf_I4);
5409                         }
5410                 }
5411
5412                 void DoEmit (EmitContext ec, bool is_statement)
5413                 {
5414                         ILGenerator ig = ec.ig;
5415
5416                         EmitArrayArguments (ec);
5417                         if (is_one_dimensional)
5418                                 ig.Emit (OpCodes.Newarr, array_element_type);
5419                         else {
5420                                 if (is_builtin_type)
5421                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
5422                                 else
5423                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
5424                         }
5425
5426                         if (initializers != null){
5427                                 //
5428                                 // FIXME: Set this variable correctly.
5429                                 //
5430                                 bool dynamic_initializers = true;
5431
5432                                 if (underlying_type != TypeManager.string_type &&
5433                                     underlying_type != TypeManager.object_type) {
5434                                         if (num_automatic_initializers > 2)
5435                                                 EmitStaticInitializers (ec, dynamic_initializers || !is_statement);
5436                                 }
5437
5438                                 if (dynamic_initializers)
5439                                         EmitDynamicInitializers (ec, !is_statement);
5440                         }
5441                 }
5442
5443                 public override void Emit (EmitContext ec)
5444                 {
5445                         DoEmit (ec, false);
5446                 }
5447
5448                 public override void EmitStatement (EmitContext ec)
5449                 {
5450                         DoEmit (ec, true);
5451                 }
5452
5453         }
5454
5455         /// <summary>
5456         ///   Represents the 'this' construct
5457         /// </summary>
5458         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
5459
5460                 Block block;
5461                 VariableInfo vi;
5462
5463                 public This (Block block, Location loc)
5464                 {
5465                         this.loc = loc;
5466                         this.block = block;
5467                 }
5468
5469                 public This (Location loc)
5470                 {
5471                         this.loc = loc;
5472                 }
5473
5474                 public bool IsAssigned (EmitContext ec, Location loc)
5475                 {
5476                         if (vi == null)
5477                                 return true;
5478
5479                         return vi.IsAssigned (ec, loc);
5480                 }
5481
5482                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
5483                 {
5484                         if (vi == null)
5485                                 return true;
5486
5487                         return vi.IsFieldAssigned (ec, field_name, loc);
5488                 }
5489
5490                 public void SetAssigned (EmitContext ec)
5491                 {
5492                         if (vi != null)
5493                                 vi.SetAssigned (ec);
5494                 }
5495
5496                 public void SetFieldAssigned (EmitContext ec, string field_name)
5497                 {
5498                         if (vi != null)
5499                                 vi.SetFieldAssigned (ec, field_name);
5500                 }
5501
5502                 public override Expression DoResolve (EmitContext ec)
5503                 {
5504                         eclass = ExprClass.Variable;
5505                         type = ec.ContainerType;
5506
5507                         if (ec.IsStatic){
5508                                 Error (26, "Keyword this not valid in static code");
5509                                 return null;
5510                         }
5511
5512                         if (block != null)
5513                                 vi = block.ThisVariable;
5514
5515                         return this;
5516                 }
5517
5518                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5519                 {
5520                         DoResolve (ec);
5521
5522                         VariableInfo vi = ec.CurrentBlock.ThisVariable;
5523                         if (vi != null)
5524                                 vi.SetAssigned (ec);
5525
5526                         if (ec.TypeContainer is Class){
5527                                 Error (1604, "Cannot assign to 'this'");
5528                                 return null;
5529                         }
5530
5531                         return this;
5532                 }
5533
5534                 public override void Emit (EmitContext ec)
5535                 {
5536                         ILGenerator ig = ec.ig;
5537
5538                         ig.Emit (OpCodes.Ldarg_0);
5539                         if (ec.TypeContainer is Struct)
5540                                 ig.Emit (OpCodes.Ldobj, type);
5541                 }
5542
5543                 public void EmitAssign (EmitContext ec, Expression source)
5544                 {
5545                         ILGenerator ig = ec.ig;
5546
5547                         if (ec.TypeContainer is Struct){
5548                                 ig.Emit (OpCodes.Ldarg_0);
5549                                 source.Emit (ec);
5550                                 ig.Emit (OpCodes.Stobj, type);
5551                         } else {
5552                                 source.Emit (ec);
5553                                 ig.Emit (OpCodes.Starg, 0);
5554                         }
5555                 }
5556
5557                 public void AddressOf (EmitContext ec, AddressOp mode)
5558                 {
5559                         ec.ig.Emit (OpCodes.Ldarg_0);
5560
5561                         // FIMXE
5562                         // FIGURE OUT WHY LDARG_S does not work
5563                         //
5564                         // consider: struct X { int val; int P { set { val = value; }}}
5565                         //
5566                         // Yes, this looks very bad. Look at 'NOTAS' for
5567                         // an explanation.
5568                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
5569                 }
5570         }
5571
5572         /// <summary>
5573         ///   Implements the typeof operator
5574         /// </summary>
5575         public class TypeOf : Expression {
5576                 public readonly Expression QueriedType;
5577                 Type typearg;
5578
5579                 public TypeOf (Expression queried_type, Location l)
5580                 {
5581                         QueriedType = queried_type;
5582                         loc = l;
5583                 }
5584
5585                 public override Expression DoResolve (EmitContext ec)
5586                 {
5587                         typearg = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5588
5589                         if (typearg == null)
5590                                 return null;
5591
5592                         type = TypeManager.type_type;
5593                         eclass = ExprClass.Type;
5594                         return this;
5595                 }
5596
5597                 public override void Emit (EmitContext ec)
5598                 {
5599                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
5600                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
5601                 }
5602
5603                 public Type TypeArg {
5604                         get { return typearg; }
5605                 }
5606         }
5607
5608         /// <summary>
5609         ///   Implements the sizeof expression
5610         /// </summary>
5611         public class SizeOf : Expression {
5612                 public readonly Expression QueriedType;
5613                 Type type_queried;
5614
5615                 public SizeOf (Expression queried_type, Location l)
5616                 {
5617                         this.QueriedType = queried_type;
5618                         loc = l;
5619                 }
5620
5621                 public override Expression DoResolve (EmitContext ec)
5622                 {
5623                         if (!ec.InUnsafe) {
5624                                 Error (233, "Sizeof may only be used in an unsafe context " +
5625                                        "(consider using System.Runtime.InteropServices.Marshal.Sizeof");
5626                                 return null;
5627                         }
5628
5629                         type_queried = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5630                         if (type_queried == null)
5631                                 return null;
5632
5633                         if (!TypeManager.IsUnmanagedType (type_queried)){
5634                                 Report.Error (208, "Cannot take the size of an unmanaged type (" + TypeManager.MonoBASIC_Name (type_queried) + ")");
5635                                 return null;
5636                         }
5637
5638                         type = TypeManager.int32_type;
5639                         eclass = ExprClass.Value;
5640                         return this;
5641                 }
5642
5643                 public override void Emit (EmitContext ec)
5644                 {
5645                         int size = GetTypeSize (type_queried);
5646
5647                         if (size == 0)
5648                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
5649                         else
5650                                 IntConstant.EmitInt (ec.ig, size);
5651                 }
5652         }
5653
5654         /// <summary>
5655         ///   Implements the member access expression
5656         /// </summary>
5657         public class MemberAccess : Expression, ITypeExpression {
5658                 public readonly string Identifier;
5659                 Expression expr;
5660                 Expression member_lookup;
5661
5662                 public MemberAccess (Expression expr, string id, Location l)
5663                 {
5664                         this.expr = expr;
5665                         Identifier = id;
5666                         loc = l;
5667                 }
5668
5669                 public Expression Expr {
5670                         get {
5671                                 return expr;
5672                         }
5673                 }
5674
5675                 static void error176 (Location loc, string name)
5676                 {
5677                         Report.Error (176, loc, "Static member '" +
5678                                       name + "' cannot be accessed " +
5679                                       "with an instance reference, qualify with a " +
5680                                       "type name instead");
5681                 }
5682
5683                 static bool IdenticalNameAndTypeName (EmitContext ec, Expression left_original, Location loc)
5684                 {
5685                         if (left_original == null)
5686                                 return false;
5687
5688                         if (!(left_original is SimpleName))
5689                                 return false;
5690
5691                         SimpleName sn = (SimpleName) left_original;
5692
5693                         Type t = RootContext.LookupType (ec.DeclSpace, sn.Name, true, loc);
5694                         if (t != null)
5695                                 return true;
5696
5697                         return false;
5698                 }
5699
5700                 public static Expression ResolveMemberAccess (EmitContext ec, Expression member_lookup,
5701                                                               Expression left, Location loc,
5702                                                               Expression left_original)
5703                 {
5704                         bool left_is_type, left_is_explicit;
5705
5706                         // If 'left' is null, then we're called from SimpleNameResolve and this is
5707                         // a member in the currently defining class.
5708                         if (left == null) {
5709                                 left_is_type = ec.IsStatic || ec.IsFieldInitializer;
5710                                 left_is_explicit = false;
5711
5712                                 // Implicitly default to 'this' unless we're static.
5713                                 if (!ec.IsStatic && !ec.IsFieldInitializer && !ec.InEnumContext)
5714                                         left = ec.This;
5715                         } else {
5716                                 left_is_type = left is TypeExpr;
5717                                 left_is_explicit = true;
5718                         }
5719
5720                         if (member_lookup is FieldExpr){
5721                                 FieldExpr fe = (FieldExpr) member_lookup;
5722                                 FieldInfo fi = fe.FieldInfo;
5723                                 Type decl_type = fi.DeclaringType;
5724
5725                                 if (fi is FieldBuilder) {
5726                                         Const c = TypeManager.LookupConstant ((FieldBuilder) fi);
5727
5728                                         if (c != null) {
5729                                                 object o = c.LookupConstantValue (ec);
5730                                                 object real_value = ((Constant) c.Expr).GetValue ();
5731
5732                                                 return Constantify (real_value, fi.FieldType);
5733                                         }
5734                                 }
5735
5736                                 if (fi.IsLiteral) {
5737                                         Type t = fi.FieldType;
5738
5739                                         object o;
5740
5741                                         if (fi is FieldBuilder)
5742                                                 o = TypeManager.GetValue ((FieldBuilder) fi);
5743                                         else
5744                                                 o = fi.GetValue (fi);
5745
5746                                         if (decl_type.IsSubclassOf (TypeManager.enum_type)) {
5747                                                 if (left_is_explicit && !left_is_type &&
5748                                                     !IdenticalNameAndTypeName (ec, left_original, loc)) {
5749                                                         error176 (loc, fe.FieldInfo.Name);
5750                                                         return null;
5751                                                 }
5752
5753                                                 Expression enum_member = MemberLookup (
5754                                                         ec, decl_type, "value__", MemberTypes.Field,
5755                                                         AllBindingFlags, loc);
5756
5757                                                 Enum en = TypeManager.LookupEnum (decl_type);
5758
5759                                                 Constant c;
5760                                                 if (en != null) {
5761                                                         c = Constantify (o, en.UnderlyingType);
5762                                                         return new EnumConstant (c, en.UnderlyingType);
5763                                                 }
5764                                                 else {
5765                                                         c = Constantify (o, enum_member.Type);
5766                                                         return new EnumConstant (c, enum_member.Type);
5767                                                 }
5768
5769
5770                                         }
5771
5772                                         Expression exp = Constantify (o, t);
5773
5774                                         if (left_is_explicit && !left_is_type) {
5775                                                 error176 (loc, fe.FieldInfo.Name);
5776                                                 return null;
5777                                         }
5778
5779                                         return exp;
5780                                 }
5781
5782                                 if (fi.FieldType.IsPointer && !ec.InUnsafe){
5783                                         UnsafeError (loc);
5784                                         return null;
5785                                 }
5786                         }
5787
5788                         if (member_lookup is EventExpr) {
5789
5790                                 EventExpr ee = (EventExpr) member_lookup;
5791
5792                                 //
5793                                 // If the event is local to this class, we transform ourselves into
5794                                 // a FieldExpr
5795                                 //
5796
5797                                 if (ee.EventInfo.DeclaringType == ec.ContainerType) {
5798                                         MemberInfo mi = GetFieldFromEvent (ee);
5799
5800                                         if (mi == null) {
5801                                                 //
5802                                                 // If this happens, then we have an event with its own
5803                                                 // accessors and private field etc so there's no need
5804                                                 // to transform ourselves : we should instead flag an error
5805                                                 //
5806                                                 Assign.error70 (ee.EventInfo, loc);
5807                                                 return null;
5808                                         }
5809
5810                                         Expression ml = ExprClassFromMemberInfo (ec, mi, loc);
5811
5812                                         if (ml == null) {
5813                                                 Report.Error (-200, loc, "Internal error!!");
5814                                                 return null;
5815                                         }
5816
5817                                         return ResolveMemberAccess (ec, ml, left, loc, left_original);
5818                                 }
5819                         }
5820
5821                         if (member_lookup is IMemberExpr) {
5822                                 IMemberExpr me = (IMemberExpr) member_lookup;
5823
5824                                 if (left_is_type){
5825                                         MethodGroupExpr mg = me as MethodGroupExpr;
5826                                         if ((mg != null) && left_is_explicit && left.Type.IsInterface)
5827                                                 mg.IsExplicitImpl = left_is_explicit;
5828
5829                                         if (!me.IsStatic){
5830                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5831                                                         return member_lookup;
5832
5833                                                 SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
5834                                                 return null;
5835                                         }
5836
5837                                 } else {
5838                                         if (!me.IsInstance){
5839                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5840                                                         return member_lookup;
5841
5842                                                 /*if (left_is_explicit) {
5843                                                         error176 (loc, me.Name);
5844                                                         return null;
5845                                                 }*/
5846                                         }
5847
5848                                         //
5849                                         // Since we can not check for instance objects in SimpleName,
5850                                         // becaue of the rule that allows types and variables to share
5851                                         // the name (as long as they can be de-ambiguated later, see
5852                                         // IdenticalNameAndTypeName), we have to check whether left
5853                                         // is an instance variable in a static context
5854                                         //
5855                                         // However, if the left-hand value is explicitly given, then
5856                                         // it is already our instance expression, so we aren't in
5857                                         // static context.
5858                                         //
5859
5860                                         if (ec.IsStatic && !left_is_explicit && left is IMemberExpr){
5861                                                 IMemberExpr mexp = (IMemberExpr) left;
5862
5863                                                 if (!mexp.IsStatic){
5864                                                         SimpleName.Error_ObjectRefRequired (ec, loc, mexp.Name);
5865                                                         return null;
5866                                                 }
5867                                         }
5868
5869                                         me.InstanceExpression = left;
5870                                 }
5871
5872                                 return member_lookup;
5873                         }
5874
5875                         if (member_lookup is TypeExpr){
5876                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5877                                 return member_lookup;
5878                         }
5879
5880                         Console.WriteLine ("Left is: " + left);
5881                         Report.Error (-100, loc, "Support for [" + member_lookup + "] is not present yet");
5882                         Environment.Exit (0);
5883                         return null;
5884                 }
5885
5886                 public Expression DoResolve (EmitContext ec, Expression right_side, ResolveFlags flags)
5887                 {
5888                         if (type != null)
5889                                 throw new Exception ();
5890                         //
5891                         // Resolve the expression with flow analysis turned off, we'll do the definite
5892                         // assignment checks later.  This is because we don't know yet what the expression
5893                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
5894                         // definite assignment check on the actual field and not on the whole struct.
5895                         //
5896
5897                         Expression original = expr;
5898                         expr = expr.Resolve (ec, flags | ResolveFlags.DisableFlowAnalysis);
5899
5900                         if (expr == null)
5901                                 return null;
5902
5903                         if (expr is SimpleName){
5904                                 SimpleName child_expr = (SimpleName) expr;
5905
5906                                 Expression new_expr = new SimpleName (child_expr.Name + "." + Identifier, loc);
5907
5908                                 if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
5909                                         return new_expr.Resolve (ec, flags);
5910                                 else
5911                                         return new_expr.Resolve (ec, flags | ResolveFlags.MethodGroup | ResolveFlags.VariableOrValue);
5912                         }
5913
5914                         int errors = Report.Errors;
5915
5916                         Type expr_type = expr.Type;
5917
5918                         if (expr_type.IsPointer){
5919                                 Error (23, "The '.' operator can not be applied to pointer operands (" +
5920                                        TypeManager.MonoBASIC_Name (expr_type) + ")");
5921                                 return null;
5922                         }
5923
5924                         member_lookup = MemberLookup (ec, expr_type, Identifier, loc);
5925
5926                         if (member_lookup == null)
5927                         {
5928                                 // Error has already been reported.
5929                                 if (errors < Report.Errors)
5930                                         return null;
5931
5932                                 //
5933                                 // Try looking the member up from the same type, if we find
5934                                 // it, we know that the error was due to limited visibility
5935                                 //
5936                                 object lookup = TypeManager.MemberLookup (
5937                                         expr_type, expr_type, AllMemberTypes, AllBindingFlags |
5938                                         BindingFlags.NonPublic, Identifier);
5939
5940                                 if (lookup == null)
5941                                         Error (30456, "'" + expr_type + "' does not contain a definition for '" + Identifier + "'");
5942                                 else
5943                                 {
5944                                         if ((expr_type != ec.ContainerType) &&
5945                                                  ec.ContainerType.IsSubclassOf (expr_type))
5946                                         {
5947
5948                                                 // Although a derived class can access protected members of
5949                                                 // its base class it cannot do so through an instance of the
5950                                                 // base class (CS1540).  If the expr_type is a parent of the
5951                                                 // ec.ContainerType and the lookup succeeds with the latter one,
5952                                                 // then we are in this situation.
5953
5954                                                 lookup = TypeManager.MemberLookup(
5955                                                                         ec.ContainerType, ec.ContainerType, AllMemberTypes,
5956                                                                         AllBindingFlags, Identifier);
5957
5958                                                 if (lookup != null)
5959                                                         Error (1540, "Cannot access protected member '" +
5960                                                        expr_type + "." + Identifier + "' " +
5961                                                        "via a qualifier of type '" + TypeManager.MonoBASIC_Name (expr_type) + "'; the " +
5962                                                        "qualifier must be of type '" + TypeManager.MonoBASIC_Name (ec.ContainerType) + "' " +
5963                                                        "(or derived from it)");
5964                                                 else
5965                                                         Error (30390, "'" + expr_type + "." + Identifier + "' " +
5966                                                        "is inaccessible because of its protection level");
5967                                         } else
5968                                                 Error (30390, "'" + expr_type + "." + Identifier + "' " +
5969                                                "is inaccessible because of its protection level");
5970                                 }
5971                                 return null;
5972                         }
5973
5974                         if ((expr is TypeExpr) && (expr_type.IsSubclassOf (TypeManager.enum_type)))     {
5975                                 Enum en = TypeManager.LookupEnum (expr_type);
5976
5977                                 if (en != null) {
5978                                         object value = en.LookupEnumValue (ec, Identifier, loc);
5979                                         expr_type = TypeManager.int32_type;
5980                                         if (value != null) {
5981                                                 Constant c = Constantify (value, en.UnderlyingType);
5982                                                 return new EnumConstant (c, en.UnderlyingType);
5983                                         }
5984                                 }
5985                         }
5986
5987                         if (member_lookup is TypeExpr){
5988                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5989
5990                                 return member_lookup;
5991                         } else if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
5992                                 return null;
5993
5994                         member_lookup = ResolveMemberAccess (ec, member_lookup, expr, loc, original);
5995                         if (member_lookup == null)
5996                                 return null;
5997
5998                         // The following DoResolve/DoResolveLValue will do the definite assignment
5999                         // check.
6000                         if (right_side != null)
6001                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
6002                         else
6003                                 member_lookup = member_lookup.DoResolve (ec);
6004
6005                         return member_lookup;
6006                 }
6007
6008                 public override Expression DoResolve (EmitContext ec)
6009                 {
6010                         return DoResolve (ec, null, ResolveFlags.VariableOrValue |
6011                                           ResolveFlags.SimpleName | ResolveFlags.Type);
6012                 }
6013
6014                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6015                 {
6016                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue |
6017                                           ResolveFlags.SimpleName | ResolveFlags.Type);
6018                 }
6019
6020                 public Expression DoResolveType (EmitContext ec)
6021                 {
6022                         return DoResolve (ec, null, ResolveFlags.Type);
6023                 }
6024
6025                 public override void Emit (EmitContext ec)
6026                 {
6027                         throw new Exception ("Should not happen");
6028                 }
6029
6030                 public override string ToString ()
6031                 {
6032                         return expr + "." + Identifier;
6033                 }
6034         }
6035
6036
6037
6038         /// <summary>
6039         ///   Implements checked expressions
6040         /// </summary>
6041         public class CheckedExpr : Expression {
6042
6043                 public Expression Expr;
6044
6045                 public CheckedExpr (Expression e, Location l)
6046                 {
6047                         Expr = e;
6048                         loc = l;
6049                 }
6050
6051                 public override Expression DoResolve (EmitContext ec)
6052                 {
6053                         bool last_const_check = ec.ConstantCheckState;
6054
6055                         ec.ConstantCheckState = true;
6056                         Expr = Expr.Resolve (ec);
6057                         ec.ConstantCheckState = last_const_check;
6058
6059                         if (Expr == null)
6060                                 return null;
6061
6062                         if (Expr is Constant)
6063                                 return Expr;
6064
6065                         eclass = Expr.eclass;
6066                         type = Expr.Type;
6067                         return this;
6068                 }
6069
6070                 public override void Emit (EmitContext ec)
6071                 {
6072                         bool last_check = ec.CheckState;
6073                         bool last_const_check = ec.ConstantCheckState;
6074
6075                         ec.CheckState = true;
6076                         ec.ConstantCheckState = true;
6077                         Expr.Emit (ec);
6078                         ec.CheckState = last_check;
6079                         ec.ConstantCheckState = last_const_check;
6080                 }
6081
6082         }
6083
6084         /// <summary>
6085         ///   Implements the unchecked expression
6086         /// </summary>
6087         public class UnCheckedExpr : Expression {
6088
6089                 public Expression Expr;
6090
6091                 public UnCheckedExpr (Expression e, Location l)
6092                 {
6093                         Expr = e;
6094                         loc = l;
6095                 }
6096
6097                 public override Expression DoResolve (EmitContext ec)
6098                 {
6099                         bool last_const_check = ec.ConstantCheckState;
6100
6101                         ec.ConstantCheckState = false;
6102                         Expr = Expr.Resolve (ec);
6103                         ec.ConstantCheckState = last_const_check;
6104
6105                         if (Expr == null)
6106                                 return null;
6107
6108                         if (Expr is Constant)
6109                                 return Expr;
6110
6111                         eclass = Expr.eclass;
6112                         type = Expr.Type;
6113                         return this;
6114                 }
6115
6116                 public override void Emit (EmitContext ec)
6117                 {
6118                         bool last_check = ec.CheckState;
6119                         bool last_const_check = ec.ConstantCheckState;
6120
6121                         ec.CheckState = false;
6122                         ec.ConstantCheckState = false;
6123                         Expr.Emit (ec);
6124                         ec.CheckState = last_check;
6125                         ec.ConstantCheckState = last_const_check;
6126                 }
6127
6128         }
6129
6130         /// <summary>
6131         ///   An Element Access expression.
6132         ///
6133         ///   During semantic analysis these are transformed into
6134         ///   IndexerAccess or ArrayAccess
6135         /// </summary>
6136         public class ElementAccess : Expression {
6137                 public ArrayList  Arguments;
6138                 public Expression Expr;
6139
6140                 public ElementAccess (Expression e, ArrayList e_list, Location l)
6141                 {
6142                         Expr = e;
6143
6144                         loc  = l;
6145
6146                         if (e_list == null)
6147                                 return;
6148
6149                         Arguments = new ArrayList ();
6150                         foreach (Expression tmp in e_list)
6151                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
6152
6153                 }
6154
6155                 bool CommonResolve (EmitContext ec)
6156                 {
6157                         Expr = Expr.Resolve (ec);
6158
6159                         if (Expr == null)
6160                                 return false;
6161
6162                         if (Arguments == null)
6163                                 return false;
6164
6165                         foreach (Argument a in Arguments){
6166                                 if (!a.Resolve (ec, loc))
6167                                         return false;
6168                         }
6169
6170                         return true;
6171                 }
6172
6173                 Expression MakePointerAccess ()
6174                 {
6175                         Type t = Expr.Type;
6176
6177                         if (t == TypeManager.void_ptr_type){
6178                                 Error (
6179                                         242,
6180                                         "The array index operation is not valid for void pointers");
6181                                 return null;
6182                         }
6183                         if (Arguments.Count != 1){
6184                                 Error (
6185                                         196,
6186                                         "A pointer must be indexed by a single value");
6187                                 return null;
6188                         }
6189                         Expression p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr,
6190                                                               t, loc);
6191                         return new Indirection (p, loc);
6192                 }
6193
6194                 public override Expression DoResolve (EmitContext ec)
6195                 {
6196                         if (!CommonResolve (ec))
6197                                 return null;
6198
6199                         //
6200                         // We perform some simple tests, and then to "split" the emit and store
6201                         // code we create an instance of a different class, and return that.
6202                         //
6203                         // I am experimenting with this pattern.
6204                         //
6205                         Type t = Expr.Type;
6206
6207                         if (t.IsArray)
6208                                 return (new ArrayAccess (this, loc)).Resolve (ec);
6209                         else if (t.IsPointer)
6210                                 return MakePointerAccess ();
6211                         else
6212                                 return (new IndexerAccess (this, loc)).Resolve (ec);
6213                 }
6214
6215                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6216                 {
6217                         if (!CommonResolve (ec))
6218                                 return null;
6219
6220                         Type t = Expr.Type;
6221                         if (t.IsArray)
6222                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
6223                         else if (t.IsPointer)
6224                                 return MakePointerAccess ();
6225                         else
6226                                 return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
6227                 }
6228
6229                 public override void Emit (EmitContext ec)
6230                 {
6231                         throw new Exception ("Should never be reached");
6232                 }
6233         }
6234
6235         /// <summary>
6236         ///   Implements array access
6237         /// </summary>
6238         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
6239                 //
6240                 // Points to our "data" repository
6241                 //
6242                 ElementAccess ea;
6243
6244                 LocalTemporary [] cached_locations;
6245
6246                 public ArrayAccess (ElementAccess ea_data, Location l)
6247                 {
6248                         ea = ea_data;
6249                         eclass = ExprClass.Variable;
6250                         loc = l;
6251                 }
6252
6253                 public override Expression DoResolve (EmitContext ec)
6254                 {
6255                         ExprClass eclass = ea.Expr.eclass;
6256
6257 #if false
6258                         // As long as the type is valid
6259                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
6260                               eclass == ExprClass.Value)) {
6261                                 ea.Expr.Error118 ("variable or value");
6262                                 return null;
6263                         }
6264 #endif
6265
6266                         Type t = ea.Expr.Type;
6267 /*
6268                         if (t == typeof (System.Object))
6269                         {
6270                                 // We can't resolve now, but we
6271                                 // have to try to access the array with a call
6272                                 // to LateIndexGet in the runtime
6273
6274                                 Expression lig_call_expr = Mono.MonoBASIC.Parser.DecomposeQI("Microsoft.VisualBasic.CompilerServices.LateBinding.LateIndexGet", Location.Null);
6275                                 Expression obj_type = Mono.MonoBASIC.Parser.DecomposeQI("System.Object", Location.Null);
6276                                 ArrayList adims = new ArrayList();
6277
6278                                 ArrayList ainit = new ArrayList();
6279                                 foreach (Argument a in ea.Arguments)
6280                                         ainit.Add ((Expression) a.Expr);
6281
6282                                 adims.Add ((Expression) new IntLiteral (ea.Arguments.Count));
6283
6284                                 Expression oace = new ArrayCreation (obj_type, adims, "", ainit, Location.Null);
6285
6286                                 ArrayList args = new ArrayList();
6287                                 args.Add (new Argument(ea.Expr, Argument.AType.Expression));
6288                                 args.Add (new Argument(oace, Argument.AType.Expression));
6289                                 args.Add (new Argument(NullLiteral.Null, Argument.AType.Expression));
6290
6291                                 Expression lig_call = new Invocation (lig_call_expr, args, Location.Null);
6292                                 lig_call = lig_call.Resolve(ec);
6293                                 return lig_call;
6294                         }
6295 */
6296                         if (t.GetArrayRank () != ea.Arguments.Count){
6297                                 ea.Error (22,
6298                                           "Incorrect number of indexes for array " +
6299                                           " expected: " + t.GetArrayRank () + " got: " +
6300                                           ea.Arguments.Count);
6301                                 return null;
6302                         }
6303                         type = TypeManager.TypeToCoreType (t.GetElementType ());
6304                         if (type.IsPointer && !ec.InUnsafe){
6305                                 UnsafeError (ea.Location);
6306                                 return null;
6307                         }
6308
6309                         foreach (Argument a in ea.Arguments){
6310                                 Type argtype = a.Type;
6311
6312                                 if (argtype == TypeManager.int32_type ||
6313                                     argtype == TypeManager.uint32_type ||
6314                                     argtype == TypeManager.int64_type ||
6315                                     argtype == TypeManager.uint64_type)
6316                                         continue;
6317
6318                                 //
6319                                 // Mhm.  This is strage, because the Argument.Type is not the same as
6320                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
6321                                 //
6322                                 // Wonder if I will run into trouble for this.
6323                                 //
6324                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
6325                                 if (a.Expr == null)
6326                                         return null;
6327                         }
6328
6329                         eclass = ExprClass.Variable;
6330
6331                         return this;
6332                 }
6333
6334                 /// <summary>
6335                 ///    Emits the right opcode to load an object of Type 't'
6336                 ///    from an array of T
6337                 /// </summary>
6338                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
6339                 {
6340                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
6341                                 ig.Emit (OpCodes.Ldelem_U1);
6342                         else if (type == TypeManager.sbyte_type)
6343                                 ig.Emit (OpCodes.Ldelem_I1);
6344                         else if (type == TypeManager.short_type)
6345                                 ig.Emit (OpCodes.Ldelem_I2);
6346                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
6347                                 ig.Emit (OpCodes.Ldelem_U2);
6348                         else if (type == TypeManager.int32_type)
6349                                 ig.Emit (OpCodes.Ldelem_I4);
6350                         else if (type == TypeManager.uint32_type)
6351                                 ig.Emit (OpCodes.Ldelem_U4);
6352                         else if (type == TypeManager.uint64_type)
6353                                 ig.Emit (OpCodes.Ldelem_I8);
6354                         else if (type == TypeManager.int64_type)
6355                                 ig.Emit (OpCodes.Ldelem_I8);
6356                         else if (type == TypeManager.float_type)
6357                                 ig.Emit (OpCodes.Ldelem_R4);
6358                         else if (type == TypeManager.double_type)
6359                                 ig.Emit (OpCodes.Ldelem_R8);
6360                         else if (type == TypeManager.intptr_type)
6361                                 ig.Emit (OpCodes.Ldelem_I);
6362                         else if (type.IsValueType){
6363                                 ig.Emit (OpCodes.Ldelema, type);
6364                                 ig.Emit (OpCodes.Ldobj, type);
6365                         } else
6366                                 ig.Emit (OpCodes.Ldelem_Ref);
6367                 }
6368
6369                 /// <summary>
6370                 ///    Emits the right opcode to store an object of Type 't'
6371                 ///    from an array of T.
6372                 /// </summary>
6373                 static public void EmitStoreOpcode (ILGenerator ig, Type t)
6374                 {
6375                         t = TypeManager.TypeToCoreType (t);
6376                         if (TypeManager.IsEnumType (t) && t != TypeManager.enum_type)
6377                                 t = TypeManager.EnumToUnderlying (t);
6378                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
6379                             t == TypeManager.bool_type)
6380                                 ig.Emit (OpCodes.Stelem_I1);
6381                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type || t == TypeManager.char_type)
6382                                 ig.Emit (OpCodes.Stelem_I2);
6383                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
6384                                 ig.Emit (OpCodes.Stelem_I4);
6385                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
6386                                 ig.Emit (OpCodes.Stelem_I8);
6387                         else if (t == TypeManager.float_type)
6388                                 ig.Emit (OpCodes.Stelem_R4);
6389                         else if (t == TypeManager.double_type)
6390                                 ig.Emit (OpCodes.Stelem_R8);
6391                         else if (t == TypeManager.intptr_type)
6392                                 ig.Emit (OpCodes.Stelem_I);
6393                         else if (t.IsValueType){
6394                                 ig.Emit (OpCodes.Stobj, t);
6395                         } else
6396                                 ig.Emit (OpCodes.Stelem_Ref);
6397                 }
6398
6399                 MethodInfo FetchGetMethod ()
6400                 {
6401                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6402                         int arg_count = ea.Arguments.Count;
6403                         Type [] args = new Type [arg_count];
6404                         MethodInfo get;
6405
6406                         for (int i = 0; i < arg_count; i++){
6407                                 //args [i++] = a.Type;
6408                                 args [i] = TypeManager.int32_type;
6409                         }
6410
6411                         get = mb.GetArrayMethod (
6412                                 ea.Expr.Type, "Get",
6413                                 CallingConventions.HasThis |
6414                                 CallingConventions.Standard,
6415                                 type, args);
6416                         return get;
6417                 }
6418
6419
6420                 MethodInfo FetchAddressMethod ()
6421                 {
6422                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6423                         int arg_count = ea.Arguments.Count;
6424                         Type [] args = new Type [arg_count];
6425                         MethodInfo address;
6426                         string ptr_type_name;
6427                         Type ret_type;
6428
6429                         ptr_type_name = type.FullName + "&";
6430                         ret_type = Type.GetType (ptr_type_name);
6431
6432                         //
6433                         // It is a type defined by the source code we are compiling
6434                         //
6435                         if (ret_type == null){
6436                                 ret_type = mb.GetType (ptr_type_name);
6437                         }
6438
6439                         for (int i = 0; i < arg_count; i++){
6440                                 //args [i++] = a.Type;
6441                                 args [i] = TypeManager.int32_type;
6442                         }
6443
6444                         address = mb.GetArrayMethod (
6445                                 ea.Expr.Type, "Address",
6446                                 CallingConventions.HasThis |
6447                                 CallingConventions.Standard,
6448                                 ret_type, args);
6449
6450                         return address;
6451                 }
6452
6453                 //
6454                 // Load the array arguments into the stack.
6455                 //
6456                 // If we have been requested to cache the values (cached_locations array
6457                 // initialized), then load the arguments the first time and store them
6458                 // in locals.  otherwise load from local variables.
6459                 //
6460                 void LoadArrayAndArguments (EmitContext ec)
6461                 {
6462                         ILGenerator ig = ec.ig;
6463
6464                         if (cached_locations == null){
6465                                 ea.Expr.Emit (ec);
6466                                 foreach (Argument a in ea.Arguments){
6467                                         Type argtype = a.Expr.Type;
6468
6469                                         a.Expr.Emit (ec);
6470
6471                                         if (argtype == TypeManager.int64_type)
6472                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6473                                         else if (argtype == TypeManager.uint64_type)
6474                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6475                                 }
6476                                 return;
6477                         }
6478
6479                         if (cached_locations [0] == null){
6480                                 cached_locations [0] = new LocalTemporary (ec, ea.Expr.Type);
6481                                 ea.Expr.Emit (ec);
6482                                 ig.Emit (OpCodes.Dup);
6483                                 cached_locations [0].Store (ec);
6484
6485                                 int j = 1;
6486
6487                                 foreach (Argument a in ea.Arguments){
6488                                         Type argtype = a.Expr.Type;
6489
6490                                         cached_locations [j] = new LocalTemporary (ec, TypeManager.intptr_type /* a.Expr.Type */);
6491                                         a.Expr.Emit (ec);
6492                                         if (argtype == TypeManager.int64_type)
6493                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6494                                         else if (argtype == TypeManager.uint64_type)
6495                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6496
6497                                         ig.Emit (OpCodes.Dup);
6498                                         cached_locations [j].Store (ec);
6499                                         j++;
6500                                 }
6501                                 return;
6502                         }
6503
6504                         foreach (LocalTemporary lt in cached_locations)
6505                                 lt.Emit (ec);
6506                 }
6507
6508                 public new void CacheTemporaries (EmitContext ec)
6509                 {
6510                         cached_locations = new LocalTemporary [ea.Arguments.Count + 1];
6511                 }
6512
6513                 public override void Emit (EmitContext ec)
6514                 {
6515                         int rank = ea.Expr.Type.GetArrayRank ();
6516                         ILGenerator ig = ec.ig;
6517
6518                         LoadArrayAndArguments (ec);
6519
6520                         if (rank == 1)
6521                                 EmitLoadOpcode (ig, type);
6522                         else {
6523                                 MethodInfo method;
6524
6525                                 method = FetchGetMethod ();
6526                                 ig.Emit (OpCodes.Call, method);
6527                         }
6528                 }
6529
6530                 public void EmitAssign (EmitContext ec, Expression source)
6531                 {
6532                         int rank = ea.Expr.Type.GetArrayRank ();
6533                         ILGenerator ig = ec.ig;
6534                         Type t = source.Type;
6535
6536                         LoadArrayAndArguments (ec);
6537
6538                         //
6539                         // The stobj opcode used by value types will need
6540                         // an address on the stack, not really an array/array
6541                         // pair
6542                         //
6543                         if (rank == 1){
6544                                 if (t == TypeManager.enum_type || t == TypeManager.decimal_type ||
6545                                     (t.IsSubclassOf (TypeManager.value_type) && !TypeManager.IsEnumType (t) && !TypeManager.IsBuiltinType (t)))
6546                                         ig.Emit (OpCodes.Ldelema, t);
6547                         }
6548
6549                         source.Emit (ec);
6550
6551                         if (rank == 1)
6552                                 EmitStoreOpcode (ig, t);
6553                         else {
6554                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
6555                                 int arg_count = ea.Arguments.Count;
6556                                 Type [] args = new Type [arg_count + 1];
6557                                 MethodInfo set;
6558
6559                                 for (int i = 0; i < arg_count; i++){
6560                                         //args [i++] = a.Type;
6561                                         args [i] = TypeManager.int32_type;
6562                                 }
6563
6564                                 args [arg_count] = type;
6565
6566                                 set = mb.GetArrayMethod (
6567                                         ea.Expr.Type, "Set",
6568                                         CallingConventions.HasThis |
6569                                         CallingConventions.Standard,
6570                                         TypeManager.void_type, args);
6571
6572                                 ig.Emit (OpCodes.Call, set);
6573                         }
6574                 }
6575
6576                 public void AddressOf (EmitContext ec, AddressOp mode)
6577                 {
6578                         int rank = ea.Expr.Type.GetArrayRank ();
6579                         ILGenerator ig = ec.ig;
6580
6581                         LoadArrayAndArguments (ec);
6582
6583                         if (rank == 1){
6584                                 ig.Emit (OpCodes.Ldelema, type);
6585                         } else {
6586                                 MethodInfo address = FetchAddressMethod ();
6587                                 ig.Emit (OpCodes.Call, address);
6588                         }
6589                 }
6590         }
6591
6592
6593         class Indexers {
6594                 public ArrayList getters, setters;
6595                 static Hashtable map;
6596
6597                 static Indexers ()
6598                 {
6599                         map = new Hashtable ();
6600                 }
6601
6602                 Indexers (MemberInfo [] mi)
6603                 {
6604                         foreach (PropertyInfo property in mi){
6605                                 MethodInfo get, set;
6606
6607                                 get = property.GetGetMethod (true);
6608                                 if (get != null){
6609                                         if (getters == null)
6610                                                 getters = new ArrayList ();
6611
6612                                         getters.Add (get);
6613                                 }
6614
6615                                 set = property.GetSetMethod (true);
6616                                 if (set != null){
6617                                         if (setters == null)
6618                                                 setters = new ArrayList ();
6619                                         setters.Add (set);
6620                                 }
6621                         }
6622                 }
6623
6624                 static private Indexers GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
6625                 {
6626                         Indexers ix = (Indexers) map [lookup_type];
6627
6628                         if (ix != null)
6629                                 return ix;
6630
6631                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
6632
6633                         MemberInfo [] mi = TypeManager.MemberLookup (
6634                                 caller_type, lookup_type, MemberTypes.Property,
6635                                 BindingFlags.Public | BindingFlags.Instance, p_name);
6636
6637                         if (mi == null || mi.Length == 0)
6638                                 return null;
6639
6640                         ix = new Indexers (mi);
6641                         map [lookup_type] = ix;
6642
6643                         return ix;
6644                 }
6645
6646                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
6647                 {
6648                         Indexers ix = (Indexers) map [lookup_type];
6649
6650                         if (ix != null)
6651                                 return ix;
6652
6653                         ix = GetIndexersForTypeOrInterface (caller_type, lookup_type);
6654                         if (ix != null)
6655                                 return ix;
6656
6657                         Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
6658                         if (ifaces != null) {
6659                                 foreach (Type itype in ifaces) {
6660                                         ix = GetIndexersForTypeOrInterface (caller_type, itype);
6661                                         if (ix != null)
6662                                                 return ix;
6663                                 }
6664                         }
6665
6666                         Report.Error (21, loc,
6667                                       "Type '" + TypeManager.MonoBASIC_Name (lookup_type) +
6668                                       "' does not have any indexers defined");
6669                         return null;
6670                 }
6671         }
6672
6673         /// <summary>
6674         ///   Expressions that represent an indexer call.
6675         /// </summary>
6676         public class IndexerAccess : Expression, IAssignMethod {
6677                 //
6678                 // Points to our "data" repository
6679                 //
6680                 MethodInfo get, set;
6681                 Indexers ilist;
6682                 ArrayList set_arguments;
6683                 bool is_base_indexer;
6684
6685                 protected Type indexer_type;
6686                 protected Type current_type;
6687                 protected Expression instance_expr;
6688                 protected ArrayList arguments;
6689
6690                 public IndexerAccess (ElementAccess ea, Location loc)
6691                         : this (ea.Expr, false, loc)
6692                 {
6693                         this.arguments = ea.Arguments;
6694                 }
6695
6696                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
6697                                          Location loc)
6698                 {
6699                         this.instance_expr = instance_expr;
6700                         this.is_base_indexer = is_base_indexer;
6701                         this.eclass = ExprClass.Value;
6702                         this.loc = loc;
6703                 }
6704
6705                 protected virtual bool CommonResolve (EmitContext ec)
6706                 {
6707                         indexer_type = instance_expr.Type;
6708                         current_type = ec.ContainerType;
6709
6710                         return true;
6711                 }
6712
6713                 public override Expression DoResolve (EmitContext ec)
6714                 {
6715                         if (!CommonResolve (ec))
6716                                 return null;
6717
6718                         //
6719                         // Step 1: Query for all 'Item' *properties*.  Notice
6720                         // that the actual methods are pointed from here.
6721                         //
6722                         // This is a group of properties, piles of them.
6723
6724                         if (ilist == null)
6725                                 ilist = Indexers.GetIndexersForType (
6726                                         current_type, indexer_type, loc);
6727
6728                         //
6729                         // Step 2: find the proper match
6730                         //
6731                         if (ilist != null && ilist.getters != null && ilist.getters.Count > 0)
6732                                 get = (MethodInfo) Invocation.OverloadResolve (
6733                                         ec, new MethodGroupExpr (ilist.getters, loc), arguments, loc);
6734
6735                         if (get == null){
6736                                 Error (154, "indexer can not be used in this context, because " +
6737                                        "it lacks a 'get' accessor");
6738                                 return null;
6739                         }
6740
6741                         type = get.ReturnType;
6742                         if (type.IsPointer && !ec.InUnsafe){
6743                                 UnsafeError (loc);
6744                                 return null;
6745                         }
6746
6747                         eclass = ExprClass.IndexerAccess;
6748                         return this;
6749                 }
6750
6751                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6752                 {
6753                         if (!CommonResolve (ec))
6754                                 return null;
6755
6756                         Type right_type = right_side.Type;
6757
6758                         if (ilist == null)
6759                                 ilist = Indexers.GetIndexersForType (
6760                                         current_type, indexer_type, loc);
6761
6762                         if (ilist != null && ilist.setters != null && ilist.setters.Count > 0){
6763                                 set_arguments = (ArrayList) arguments.Clone ();
6764                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
6765
6766                                 set = (MethodInfo) Invocation.OverloadResolve (
6767                                         ec, new MethodGroupExpr (ilist.setters, loc), set_arguments, loc);
6768                         }
6769
6770                         if (set == null){
6771                                 Error (200, "indexer X.this [" + TypeManager.MonoBASIC_Name (right_type) +
6772                                        "] lacks a 'set' accessor");
6773                                 return null;
6774                         }
6775
6776                         type = TypeManager.void_type;
6777                         eclass = ExprClass.IndexerAccess;
6778                         return this;
6779                 }
6780
6781                 public override void Emit (EmitContext ec)
6782                 {
6783                         Invocation.EmitCall (ec, false, false, instance_expr, get, arguments, loc);
6784                 }
6785
6786                 //
6787                 // source is ignored, because we already have a copy of it from the
6788                 // LValue resolution and we have already constructed a pre-cached
6789                 // version of the arguments (ea.set_arguments);
6790                 //
6791                 public void EmitAssign (EmitContext ec, Expression source)
6792                 {
6793                         Invocation.EmitCall (ec, false, false, instance_expr, set, set_arguments, loc);
6794                 }
6795         }
6796
6797         /// <summary>
6798         ///   The base operator for method names
6799         /// </summary>
6800         public class BaseAccess : Expression {
6801                 public string member;
6802
6803                 public BaseAccess (string member, Location l)
6804                 {
6805                         this.member = member;
6806                         loc = l;
6807                 }
6808
6809                 public override Expression DoResolve (EmitContext ec)
6810                 {
6811                         Expression member_lookup;
6812                         Type current_type = ec.ContainerType;
6813                         Type base_type = current_type.BaseType;
6814                         Expression e;
6815
6816                         if (ec.IsStatic){
6817                                 Error (1511, "Keyword MyBase is not allowed in static method");
6818                                 return null;
6819                         }
6820
6821                         if (member == "New")
6822                                 member = ".ctor";
6823
6824                         member_lookup = MemberLookup (ec, base_type, base_type, member,
6825                                                       AllMemberTypes, AllBindingFlags, loc);
6826
6827                         if (member_lookup == null) {
6828                                 Error (30456,
6829                                               TypeManager.MonoBASIC_Name (base_type) + " does not " +
6830                                               "contain a definition for '" + member + "'");
6831                                 return null;
6832                         }
6833
6834                         Expression left;
6835
6836                         if (ec.IsStatic)
6837                                 left = new TypeExpr (base_type, loc);
6838                         else
6839                                 left = ec.This;
6840
6841                         e = MemberAccess.ResolveMemberAccess (ec, member_lookup, left, loc, null);
6842
6843                         if (e is PropertyExpr){
6844                                 PropertyExpr pe = (PropertyExpr) e;
6845
6846                                 pe.IsBase = true;
6847                         }
6848
6849                         return e;
6850                 }
6851
6852                 public override void Emit (EmitContext ec)
6853                 {
6854                         throw new Exception ("Should never be called");
6855                 }
6856         }
6857
6858         /// <summary>
6859         ///   The base indexer operator
6860         /// </summary>
6861         public class BaseIndexerAccess : IndexerAccess {
6862                 public BaseIndexerAccess (ArrayList args, Location loc)
6863                         : base (null, true, loc)
6864                 {
6865                         arguments = new ArrayList ();
6866                         foreach (Expression tmp in args)
6867                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
6868                 }
6869
6870                 protected override bool CommonResolve (EmitContext ec)
6871                 {
6872                         instance_expr = ec.This;
6873
6874                         current_type = ec.ContainerType.BaseType;
6875                         indexer_type = current_type;
6876
6877                         foreach (Argument a in arguments){
6878                                 if (!a.Resolve (ec, loc))
6879                                         return false;
6880                         }
6881
6882                         return true;
6883                 }
6884         }
6885
6886         /// <summary>
6887         ///   This class exists solely to pass the Type around and to be a dummy
6888         ///   that can be passed to the conversion functions (this is used by
6889         ///   foreach implementation to typecast the object return value from
6890         ///   get_Current into the proper type.  All code has been generated and
6891         ///   we only care about the side effect conversions to be performed
6892         ///
6893         ///   This is also now used as a placeholder where a no-action expression
6894         ///   is needed (the 'New' class).
6895         /// </summary>
6896         public class EmptyExpression : Expression {
6897                 public EmptyExpression ()
6898                 {
6899                         type = TypeManager.object_type;
6900                         eclass = ExprClass.Value;
6901                         loc = Location.Null;
6902                 }
6903
6904                 public EmptyExpression (Type t)
6905                 {
6906                         type = t;
6907                         eclass = ExprClass.Value;
6908                         loc = Location.Null;
6909                 }
6910
6911                 public override Expression DoResolve (EmitContext ec)
6912                 {
6913                         return this;
6914                 }
6915
6916                 public override void Emit (EmitContext ec)
6917                 {
6918                         // nothing, as we only exist to not do anything.
6919                 }
6920
6921                 //
6922                 // This is just because we might want to reuse this bad boy
6923                 // instead of creating gazillions of EmptyExpressions.
6924                 // (CanConvertImplicit uses it)
6925                 //
6926                 public void SetType (Type t)
6927                 {
6928                         type = t;
6929                 }
6930         }
6931
6932         public class UserCast : Expression {
6933                 MethodBase method;
6934                 Expression source;
6935
6936                 public UserCast (MethodInfo method, Expression source, Location l)
6937                 {
6938                         this.method = method;
6939                         this.source = source;
6940                         type = method.ReturnType;
6941                         eclass = ExprClass.Value;
6942                         loc = l;
6943                 }
6944
6945                 public override Expression DoResolve (EmitContext ec)
6946                 {
6947                         //
6948                         // We are born fully resolved
6949                         //
6950                         return this;
6951                 }
6952
6953                 public override void Emit (EmitContext ec)
6954                 {
6955                         ILGenerator ig = ec.ig;
6956
6957                         source.Emit (ec);
6958
6959                         if (method is MethodInfo)
6960                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
6961                         else
6962                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
6963
6964                 }
6965         }
6966
6967         // <summary>
6968         //   This class is used to "construct" the type during a typecast
6969         //   operation.  Since the Type.GetType class in .NET can parse
6970         //   the type specification, we just use this to construct the type
6971         //   one bit at a time.
6972         // </summary>
6973         public class ComposedCast : Expression, ITypeExpression {
6974                 Expression left;
6975                 string dim;
6976
6977                 public ComposedCast (Expression left, string dim, Location l)
6978                 {
6979                         this.left = left;
6980                         this.dim = dim;
6981                         loc = l;
6982                 }
6983
6984                 public Expression DoResolveType (EmitContext ec)
6985                 {
6986                         Type ltype = ec.DeclSpace.ResolveType (left, false, loc);
6987                         if (ltype == null)
6988                                 return null;
6989
6990                         //
6991                         // ltype.Fullname is already fully qualified, so we can skip
6992                         // a lot of probes, and go directly to TypeManager.LookupType
6993                         //
6994                         string cname = ltype.FullName + dim;
6995                         type = TypeManager.LookupTypeDirect (cname);
6996                         if (type == null){
6997                                 //
6998                                 // For arrays of enumerations we are having a problem
6999                                 // with the direct lookup.  Need to investigate.
7000                                 //
7001                                 // For now, fall back to the full lookup in that case.
7002                                 //
7003                                 type = RootContext.LookupType (
7004                                         ec.DeclSpace, cname, false, loc);
7005
7006                                 if (type == null)
7007                                         return null;
7008                         }
7009
7010                         if (!ec.ResolvingTypeTree){
7011                                 //
7012                                 // If the above flag is set, this is being invoked from the ResolveType function.
7013                                 // Upper layers take care of the type validity in this context.
7014                                 //
7015                         if (!ec.InUnsafe && type.IsPointer){
7016                                 UnsafeError (loc);
7017                                 return null;
7018                         }
7019                         }
7020
7021                         eclass = ExprClass.Type;
7022                         return this;
7023                 }
7024
7025                 public override Expression DoResolve (EmitContext ec)
7026                 {
7027                         return DoResolveType (ec);
7028                 }
7029
7030                 public override void Emit (EmitContext ec)
7031                 {
7032                         throw new Exception ("This should never be called");
7033                 }
7034
7035                 public override string ToString ()
7036                 {
7037                         return left + dim;
7038                 }
7039         }
7040
7041         //
7042         // This class is used to represent the address of an array, used
7043         // only by the Fixed statement, this is like the C "&a [0]" construct.
7044         //
7045         public class ArrayPtr : Expression {
7046                 Expression array;
7047
7048                 public ArrayPtr (Expression array, Location l)
7049                 {
7050                         Type array_type = array.Type.GetElementType ();
7051
7052                         this.array = array;
7053
7054                         string array_ptr_type_name = array_type.FullName + "*";
7055
7056                         type = Type.GetType (array_ptr_type_name);
7057                         if (type == null){
7058                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
7059
7060                                 type = mb.GetType (array_ptr_type_name);
7061                         }
7062
7063                         eclass = ExprClass.Value;
7064                         loc = l;
7065                 }
7066
7067                 public override void Emit (EmitContext ec)
7068                 {
7069                         ILGenerator ig = ec.ig;
7070
7071                         array.Emit (ec);
7072                         IntLiteral.EmitInt (ig, 0);
7073                         ig.Emit (OpCodes.Ldelema, array.Type.GetElementType ());
7074                 }
7075
7076                 public override Expression DoResolve (EmitContext ec)
7077                 {
7078                         //
7079                         // We are born fully resolved
7080                         //
7081                         return this;
7082                 }
7083         }
7084
7085         //
7086         // Used by the fixed statement
7087         //
7088         public class StringPtr : Expression {
7089                 LocalBuilder b;
7090
7091                 public StringPtr (LocalBuilder b, Location l)
7092                 {
7093                         this.b = b;
7094                         eclass = ExprClass.Value;
7095                         type = TypeManager.char_ptr_type;
7096                         loc = l;
7097                 }
7098
7099                 public override Expression DoResolve (EmitContext ec)
7100                 {
7101                         // This should never be invoked, we are born in fully
7102                         // initialized state.
7103
7104                         return this;
7105                 }
7106
7107                 public override void Emit (EmitContext ec)
7108                 {
7109                         ILGenerator ig = ec.ig;
7110
7111                         ig.Emit (OpCodes.Ldloc, b);
7112                         ig.Emit (OpCodes.Conv_I);
7113                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
7114                         ig.Emit (OpCodes.Add);
7115                 }
7116         }
7117
7118         //
7119         // Implements the 'stackalloc' keyword
7120         //
7121         public class StackAlloc : Expression {
7122                 Type otype;
7123                 Expression t;
7124                 Expression count;
7125
7126                 public StackAlloc (Expression type, Expression count, Location l)
7127                 {
7128                         t = type;
7129                         this.count = count;
7130                         loc = l;
7131                 }
7132
7133                 public override Expression DoResolve (EmitContext ec)
7134                 {
7135                         count = count.Resolve (ec);
7136                         if (count == null)
7137                                 return null;
7138
7139                         if (count.Type != TypeManager.int32_type){
7140                                 count = ConvertImplicitRequired (ec, count, TypeManager.int32_type, loc);
7141                                 if (count == null)
7142                                         return null;
7143                         }
7144
7145                         if (ec.InCatch || ec.InFinally){
7146                                 Error (255,
7147                                               "stackalloc can not be used in a catch or finally block");
7148                                 return null;
7149                         }
7150
7151                         otype = ec.DeclSpace.ResolveType (t, false, loc);
7152
7153                         if (otype == null)
7154                                 return null;
7155
7156                         if (!TypeManager.VerifyUnManaged (otype, loc))
7157                                 return null;
7158
7159                         string ptr_name = otype.FullName + "*";
7160                         type = Type.GetType (ptr_name);
7161                         if (type == null){
7162                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
7163
7164                                 type = mb.GetType (ptr_name);
7165                         }
7166                         eclass = ExprClass.Value;
7167
7168                         return this;
7169                 }
7170
7171                 public override void Emit (EmitContext ec)
7172                 {
7173                         int size = GetTypeSize (otype);
7174                         ILGenerator ig = ec.ig;
7175
7176                         if (size == 0)
7177                                 ig.Emit (OpCodes.Sizeof, otype);
7178                         else
7179                                 IntConstant.EmitInt (ig, size);
7180                         count.Emit (ec);
7181                         ig.Emit (OpCodes.Mul);
7182                         ig.Emit (OpCodes.Localloc);
7183                 }
7184         }
7185 }