mcs/mcs/parameter.cs

   1 //
   2 // parameter.cs: Parameter definition.
   3 //
   4 // Author: Miguel de Icaza (miguel@gnu.org)
   5 //         Marek Safar (marek.safar@seznam.cz)
   6 //
   7 // Dual licensed under the terms of the MIT X11 or GNU GPL
   8 //
   9 // Copyright 2001-2003 Ximian, Inc (http://www.ximian.com)
  10 // Copyright 2003-2008 Novell, Inc.
  11 //
  12 //
  13 using System;
  14 using System.Text;
  15
  16 #if STATIC
  17 using MetaType = IKVM.Reflection.Type;
  18 using IKVM.Reflection;
  19 using IKVM.Reflection.Emit;
  20 #else
  21 using MetaType = System.Type;
  22 using System.Reflection;
  23 using System.Reflection.Emit;
  24 #endif
  25
  26 namespace Mono.CSharp {
  27
  28         /// <summary>
  29         ///   Abstract Base class for parameters of a method.
  30         /// </summary>
  31         public abstract class ParameterBase : Attributable
  32         {
  33                 protected ParameterBuilder builder;
  34
  35                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
  36                 {
  37 #if false
  38                         if (a.Type == pa.MarshalAs) {
  39                                 UnmanagedMarshal marshal = a.GetMarshal (this);
  40                                 if (marshal != null) {
  41                                         builder.SetMarshal (marshal);
  42                                 }
  43                                 return;
  44                         }
  45 #endif
  46                         if (a.HasSecurityAttribute) {
  47                                 a.Error_InvalidSecurityParent ();
  48                                 return;
  49                         }
  50
  51                         if (a.Type == pa.Dynamic) {
  52                                 a.Error_MisusedDynamicAttribute ();
  53                                 return;
  54                         }
  55
  56                         builder.SetCustomAttribute ((ConstructorInfo) ctor.GetMetaInfo (), cdata);
  57                 }
  58
  59                 public ParameterBuilder Builder {
  60                         get {
  61                                 return builder;
  62                         }
  63                 }
  64
  65                 public override bool IsClsComplianceRequired()
  66                 {
  67                         return false;
  68                 }
  69         }
  70
  71         /// <summary>
  72         /// Class for applying custom attributes on the return type
  73         /// </summary>
  74         public class ReturnParameter : ParameterBase
  75         {
  76                 MemberCore method;
  77
  78                 // TODO: merge method and mb
  79                 public ReturnParameter (MemberCore method, MethodBuilder mb, Location location)
  80                 {
  81                         this.method = method;
  82                         try {
  83                                 builder = mb.DefineParameter (0, ParameterAttributes.None, "");
  84                         }
  85                         catch (ArgumentOutOfRangeException) {
  86                                 method.Compiler.Report.RuntimeMissingSupport (location, "custom attributes on the return type");
  87                         }
  88                 }
  89
  90                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
  91                 {
  92                         if (a.Type == pa.CLSCompliant) {
  93                                 method.Compiler.Report.Warning (3023, 1, a.Location,
  94                                         "CLSCompliant attribute has no meaning when applied to return types. Try putting it on the method instead");
  95                         }
  96
  97                         // This occurs after Warning -28
  98                         if (builder == null)
  99                                 return;
 100
 101                         base.ApplyAttributeBuilder (a, ctor, cdata, pa);
 102                 }
 103
 104                 public override AttributeTargets AttributeTargets {
 105                         get {
 106                                 return AttributeTargets.ReturnValue;
 107                         }
 108                 }
 109
 110                 /// <summary>
 111                 /// Is never called
 112                 /// </summary>
 113                 public override string[] ValidAttributeTargets {
 114                         get {
 115                                 return null;
 116                         }
 117                 }
 118         }
 119
 120         public class ImplicitLambdaParameter : Parameter
 121         {
 122                 public ImplicitLambdaParameter (string name, Location loc)
 123                         : base (null, name, Modifier.NONE, null, loc)
 124                 {
 125                 }
 126
 127                 public override TypeSpec Resolve (IMemberContext ec, int index)
 128                 {
 129                         if (parameter_type == null)
 130                                 throw new InternalErrorException ("A type of implicit lambda parameter `{0}' is not set",
 131                                         Name);
 132
 133                         base.idx = index;
 134                         return parameter_type;
 135                 }
 136
 137                 public void SetParameterType (TypeSpec type)
 138                 {
 139                         parameter_type = type;
 140                 }
 141         }
 142
 143         public class ParamsParameter : Parameter {
 144                 public ParamsParameter (FullNamedExpression type, string name, Attributes attrs, Location loc):
 145                         base (type, name, Parameter.Modifier.PARAMS, attrs, loc)
 146                 {
 147                 }
 148
 149                 public override TypeSpec Resolve (IMemberContext ec, int index)
 150                 {
 151                         if (base.Resolve (ec, index) == null)
 152                                 return null;
 153
 154                         var ac = parameter_type as ArrayContainer;
 155                         if (ac == null || ac.Rank != 1) {
 156                                 ec.Module.Compiler.Report.Error (225, Location, "The params parameter must be a single dimensional array");
 157                                 return null;
 158                         }
 159
 160                         return parameter_type;
 161                 }
 162
 163                 public override void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index, PredefinedAttributes pa)
 164                 {
 165                         base.ApplyAttributes (mb, cb, index, pa);
 166                         pa.ParamArray.EmitAttribute (builder);
 167                 }
 168         }
 169
 170         public class ArglistParameter : Parameter {
 171                 // Doesn't have proper type because it's never chosen for better conversion
 172                 public ArglistParameter (Location loc) :
 173                         base (null, String.Empty, Parameter.Modifier.NONE, null, loc)
 174                 {
 175                         parameter_type = InternalType.Arglist;
 176                 }
 177
 178                 public override void  ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index, PredefinedAttributes pa)
 179                 {
 180                         // Nothing to do
 181                 }
 182
 183                 public override bool CheckAccessibility (InterfaceMemberBase member)
 184                 {
 185                         return true;
 186                 }
 187
 188                 public override TypeSpec Resolve (IMemberContext ec, int index)
 189                 {
 190                         return parameter_type;
 191                 }
 192         }
 193
 194         public interface IParameterData
 195         {
 196                 Expression DefaultValue { get; }
 197                 bool HasExtensionMethodModifier { get; }
 198                 bool HasDefaultValue { get; }
 199                 Parameter.Modifier ModFlags { get; }
 200                 string Name { get; }
 201         }
 202
 203         //
 204         // Parameter information created by parser
 205         //
 206         public class Parameter : ParameterBase, IParameterData, ILocalVariable // TODO: INamedBlockVariable
 207         {
 208                 [Flags]
 209                 public enum Modifier : byte {
 210                         NONE    = 0,
 211                         REF     = REFMASK | ISBYREF,
 212                         OUT     = OUTMASK | ISBYREF,
 213                         PARAMS  = 4,
 214                         // This is a flag which says that it's either REF or OUT.
 215                         ISBYREF = 8,
 216                         REFMASK = 32,
 217                         OUTMASK = 64,
 218                         SignatureMask = REFMASK | OUTMASK,
 219                         This    = 128
 220                 }
 221
 222                 static readonly string[] attribute_targets = new string[] { "param" };
 223
 224                 FullNamedExpression texpr;
 225                 readonly Modifier modFlags;
 226                 string name;
 227                 Expression default_expr;
 228                 protected TypeSpec parameter_type;
 229                 readonly Location loc;
 230                 protected int idx;
 231                 public bool HasAddressTaken;
 232
 233                 TemporaryVariableReference expr_tree_variable;
 234
 235                 HoistedVariable hoisted_variant;
 236
 237                 public Parameter (FullNamedExpression type, string name, Modifier mod, Attributes attrs, Location loc)
 238                 {
 239                         this.name = name;
 240                         modFlags = mod;
 241                         this.loc = loc;
 242                         texpr = type;
 243
 244                         // Only assign, attributes will be attached during resolve
 245                         base.attributes = attrs;
 246                 }
 247
 248                 #region Properties
 249
 250                 public DefaultParameterValueExpression DefaultValue {
 251                         get {
 252                                 return default_expr as DefaultParameterValueExpression;
 253                         }
 254                         set {
 255                                 default_expr = value;
 256                         }
 257                 }
 258
 259                 Expression IParameterData.DefaultValue {
 260                         get {
 261                                 var expr = default_expr as DefaultParameterValueExpression;
 262                                 return expr == null ? default_expr : expr.Child;
 263                         }
 264                 }
 265
 266                 bool HasOptionalExpression {
 267                         get {
 268                                 return default_expr is DefaultParameterValueExpression;
 269                         }
 270                 }
 271
 272                 public Location Location {
 273                         get {
 274                                 return loc;
 275                         }
 276                 }
 277
 278                 public TypeSpec Type {
 279                         get {
 280                                 return parameter_type;
 281                         }
 282                         set {
 283                                 parameter_type = value;
 284                         }
 285                 }
 286
 287                 public FullNamedExpression TypeExpression  {
 288                         get {
 289                                 return texpr;
 290                         }
 291                 }
 292
 293                 public override string[] ValidAttributeTargets {
 294                         get {
 295                                 return attribute_targets;
 296                         }
 297                 }
 298
 299                 #endregion
 300
 301                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
 302                 {
 303                         if (a.Type == pa.In && ModFlags == Modifier.OUT) {
 304                                 a.Report.Error (36, a.Location, "An out parameter cannot have the `In' attribute");
 305                                 return;
 306                         }
 307
 308                         if (a.Type == pa.ParamArray) {
 309                                 a.Report.Error (674, a.Location, "Do not use `System.ParamArrayAttribute'. Use the `params' keyword instead");
 310                                 return;
 311                         }
 312
 313                         if (a.Type == pa.Out && (ModFlags & Modifier.REF) == Modifier.REF &&
 314                             !OptAttributes.Contains (pa.In)) {
 315                                 a.Report.Error (662, a.Location,
 316                                         "Cannot specify only `Out' attribute on a ref parameter. Use both `In' and `Out' attributes or neither");
 317                                 return;
 318                         }
 319
 320                         if (a.Type == pa.CLSCompliant) {
 321                                 a.Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
 322                         }
 323
 324                         if (a.Type == pa.DefaultParameterValue || a.Type == pa.OptionalParameter) {
 325                                 if (HasOptionalExpression) {
 326                                         a.Report.Error (1745, a.Location,
 327                                                 "Cannot specify `{0}' attribute on optional parameter `{1}'",
 328                                                 TypeManager.CSharpName (a.Type).Replace ("Attribute", ""), Name);
 329                                 }
 330
 331                                 if (a.Type == pa.DefaultParameterValue)
 332                                         return;
 333                         }
 334
 335                         base.ApplyAttributeBuilder (a, ctor, cdata, pa);
 336                 }
 337
 338                 public virtual bool CheckAccessibility (InterfaceMemberBase member)
 339                 {
 340                         if (parameter_type == null)
 341                                 return true;
 342
 343                         return member.IsAccessibleAs (parameter_type);
 344                 }
 345
 346                 // <summary>
 347                 //   Resolve is used in method definitions
 348                 // </summary>
 349                 public virtual TypeSpec Resolve (IMemberContext rc, int index)
 350                 {
 351                         if (parameter_type != null)
 352                                 return parameter_type;
 353
 354                         if (attributes != null)
 355                                 attributes.AttachTo (this, rc);
 356
 357                         parameter_type = texpr.ResolveAsType (rc);
 358                         if (parameter_type == null)
 359                                 return null;
 360
 361                         this.idx = index;
 362
 363                         if ((modFlags & Parameter.Modifier.ISBYREF) != 0 && parameter_type.IsSpecialRuntimeType) {
 364                                 rc.Module.Compiler.Report.Error (1601, Location, "Method or delegate parameter cannot be of type `{0}'",
 365                                         GetSignatureForError ());
 366                                 return null;
 367                         }
 368
 369                         TypeManager.CheckTypeVariance (parameter_type,
 370                                 (modFlags & Parameter.Modifier.ISBYREF) != 0 ? Variance.None : Variance.Contravariant,
 371                                 rc);
 372
 373                         if (parameter_type.IsStatic) {
 374                                 rc.Module.Compiler.Report.Error (721, Location, "`{0}': static types cannot be used as parameters",
 375                                         texpr.GetSignatureForError ());
 376                                 return parameter_type;
 377                         }
 378
 379                         if ((modFlags & Modifier.This) != 0 && (parameter_type.IsPointer || parameter_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)) {
 380                                 rc.Module.Compiler.Report.Error (1103, Location, "The extension method cannot be of type `{0}'",
 381                                         TypeManager.CSharpName (parameter_type));
 382                         }
 383
 384                         return parameter_type;
 385                 }
 386
 387                 public void ResolveDefaultValue (ResolveContext rc)
 388                 {
 389                         //
 390                         // Default value was specified using an expression
 391                         //
 392                         if (default_expr != null) {
 393                                 ((DefaultParameterValueExpression)default_expr).Resolve (rc, this);
 394                                 return;
 395                         }
 396
 397                         if (attributes == null)
 398                                 return;
 399
 400                         var opt_attr = attributes.Search (rc.Module.PredefinedAttributes.OptionalParameter);
 401                         var def_attr = attributes.Search (rc.Module.PredefinedAttributes.DefaultParameterValue);
 402                         if (def_attr != null) {
 403                                 if (def_attr.Resolve () == null)
 404                                         return;
 405
 406                                 var default_expr_attr = def_attr.GetParameterDefaultValue ();
 407                                 if (default_expr_attr == null)
 408                                         return;
 409
 410                                 var dpa_rc = def_attr.CreateResolveContext ();
 411                                 default_expr = default_expr_attr.Resolve (dpa_rc);
 412
 413                                 if (default_expr is BoxedCast)
 414                                         default_expr = ((BoxedCast) default_expr).Child;
 415
 416                                 Constant c = default_expr as Constant;
 417                                 if (c == null) {
 418                                         if (parameter_type.BuiltinType == BuiltinTypeSpec.Type.Object) {
 419                                                 rc.Report.Error (1910, default_expr.Location,
 420                                                         "Argument of type `{0}' is not applicable for the DefaultParameterValue attribute",
 421                                                         default_expr.Type.GetSignatureForError ());
 422                                         } else {
 423                                                 rc.Report.Error (1909, default_expr.Location,
 424                                                         "The DefaultParameterValue attribute is not applicable on parameters of type `{0}'",
 425                                                         default_expr.Type.GetSignatureForError ()); ;
 426                                         }
 427
 428                                         default_expr = null;
 429                                         return;
 430                                 }
 431
 432                                 if (TypeSpecComparer.IsEqual (default_expr.Type, parameter_type) ||
 433                                         (default_expr is NullConstant && TypeSpec.IsReferenceType (parameter_type) && !parameter_type.IsGenericParameter) ||
 434                                         parameter_type.BuiltinType == BuiltinTypeSpec.Type.Object) {
 435                                         return;
 436                                 }
 437
 438                                 //
 439                                 // LAMESPEC: Some really weird csc behaviour which we have to mimic
 440                                 // User operators returning same type as parameter type are considered
 441                                 // valid for this attribute only
 442                                 //
 443                                 // struct S { public static implicit operator S (int i) {} }
 444                                 //
 445                                 // void M ([DefaultParameterValue (3)]S s)
 446                                 //
 447                                 var expr = Convert.ImplicitUserConversion (dpa_rc, default_expr, parameter_type, loc);
 448                                 if (expr != null && TypeSpecComparer.IsEqual (expr.Type, parameter_type)) {
 449                                         return;
 450                                 }
 451
 452                                 rc.Report.Error (1908, default_expr.Location, "The type of the default value should match the type of the parameter");
 453                                 return;
 454                         }
 455
 456                         if (opt_attr != null) {
 457                                 default_expr = EmptyExpression.MissingValue;
 458                         }
 459                 }
 460
 461                 public bool HasDefaultValue {
 462                         get { return default_expr != null; }
 463                 }
 464
 465                 public bool HasExtensionMethodModifier {
 466                         get { return (modFlags & Modifier.This) != 0; }
 467                 }
 468
 469                 //
 470                 // Hoisted parameter variant
 471                 //
 472                 public HoistedVariable HoistedVariant {
 473                         get {
 474                                 return hoisted_variant;
 475                         }
 476                         set {
 477                                 hoisted_variant = value;
 478                         }
 479                 }
 480
 481                 public Modifier ModFlags {
 482                         get { return modFlags & ~Modifier.This; }
 483                 }
 484
 485                 public string Name {
 486                         get { return name; }
 487                         set { name = value; }
 488                 }
 489
 490                 public override AttributeTargets AttributeTargets {
 491                         get {
 492                                 return AttributeTargets.Parameter;
 493                         }
 494                 }
 495
 496                 public void Error_DuplicateName (Report r)
 497                 {
 498                         r.Error (100, Location, "The parameter name `{0}' is a duplicate", Name);
 499                 }
 500
 501                 public virtual string GetSignatureForError ()
 502                 {
 503                         string type_name;
 504                         if (parameter_type != null)
 505                                 type_name = TypeManager.CSharpName (parameter_type);
 506                         else
 507                                 type_name = texpr.GetSignatureForError ();
 508
 509                         string mod = GetModifierSignature (modFlags);
 510                         if (mod.Length > 0)
 511                                 return String.Concat (mod, " ", type_name);
 512
 513                         return type_name;
 514                 }
 515
 516                 public static string GetModifierSignature (Modifier mod)
 517                 {
 518                         switch (mod) {
 519                         case Modifier.OUT:
 520                                 return "out";
 521                         case Modifier.PARAMS:
 522                                 return "params";
 523                         case Modifier.REF:
 524                                 return "ref";
 525                         case Modifier.This:
 526                                 return "this";
 527                         default:
 528                                 return "";
 529                         }
 530                 }
 531
 532                 public void IsClsCompliant (IMemberContext ctx)
 533                 {
 534                         if (parameter_type.IsCLSCompliant ())
 535                                 return;
 536
 537                         ctx.Module.Compiler.Report.Warning (3001, 1, Location,
 538                                 "Argument type `{0}' is not CLS-compliant", parameter_type.GetSignatureForError ());
 539                 }
 540
 541                 public virtual void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index, PredefinedAttributes pa)
 542                 {
 543                         if (builder != null)
 544                                 throw new InternalErrorException ("builder already exists");
 545
 546                         var pattrs = ParametersCompiled.GetParameterAttribute (modFlags);
 547                         if (HasOptionalExpression)
 548                                 pattrs |= ParameterAttributes.Optional;
 549
 550                         if (mb == null)
 551                                 builder = cb.DefineParameter (index, pattrs, Name);
 552                         else
 553                                 builder = mb.DefineParameter (index, pattrs, Name);
 554
 555                         if (OptAttributes != null)
 556                                 OptAttributes.Emit ();
 557
 558                         if (HasDefaultValue) {
 559                                 //
 560                                 // Emit constant values for true constants only, the other
 561                                 // constant-like expressions will rely on default value expression
 562                                 //
 563                                 var def_value = DefaultValue;
 564                                 Constant c = def_value != null ? def_value.Child as Constant : default_expr as Constant;
 565                                 if (c != null) {
 566                                         if (c.Type.BuiltinType == BuiltinTypeSpec.Type.Decimal) {
 567                                                 pa.DecimalConstant.EmitAttribute (builder, (decimal) c.GetValue (), c.Location);
 568                                         } else {
 569                                                 builder.SetConstant (c.GetValue ());
 570                                         }
 571                                 } else if (default_expr.Type.IsStruct) {
 572                                         //
 573                                         // Handles special case where default expression is used with value-type
 574                                         //
 575                                         // void Foo (S s = default (S)) {}
 576                                         //
 577                                         builder.SetConstant (null);
 578                                 }
 579                         }
 580
 581                         if (parameter_type != null) {
 582                                 if (parameter_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
 583                                         pa.Dynamic.EmitAttribute (builder);
 584                                 } else if (parameter_type.HasDynamicElement) {
 585                                         pa.Dynamic.EmitAttribute (builder, parameter_type, Location);
 586                                 }
 587                         }
 588                 }
 589
 590                 public Parameter Clone ()
 591                 {
 592                         Parameter p = (Parameter) MemberwiseClone ();
 593                         if (attributes != null)
 594                                 p.attributes = attributes.Clone ();
 595
 596                         return p;
 597                 }
 598
 599                 public ExpressionStatement CreateExpressionTreeVariable (BlockContext ec)
 600                 {
 601                         if ((modFlags & Modifier.ISBYREF) != 0)
 602                                 ec.Report.Error (1951, Location, "An expression tree parameter cannot use `ref' or `out' modifier");
 603
 604                         expr_tree_variable = TemporaryVariableReference.Create (ResolveParameterExpressionType (ec, Location).Type, ec.CurrentBlock.ParametersBlock, Location);
 605                         expr_tree_variable = (TemporaryVariableReference) expr_tree_variable.Resolve (ec);
 606
 607                         Arguments arguments = new Arguments (2);
 608                         arguments.Add (new Argument (new TypeOf (parameter_type, Location)));
 609                         arguments.Add (new Argument (new StringConstant (ec.BuiltinTypes, Name, Location)));
 610                         return new SimpleAssign (ExpressionTreeVariableReference (),
 611                                 Expression.CreateExpressionFactoryCall (ec, "Parameter", null, arguments, Location));
 612                 }
 613
 614                 public void Emit (EmitContext ec)
 615                 {
 616                         int arg_idx = idx;
 617                         if (!ec.IsStatic)
 618                                 arg_idx++;
 619
 620                         ParameterReference.EmitLdArg (ec, arg_idx);
 621                 }
 622
 623                 public void EmitAssign (EmitContext ec)
 624                 {
 625                         int arg_idx = idx;
 626                         if (!ec.IsStatic)
 627                                 arg_idx++;
 628
 629                         if (arg_idx <= 255)
 630                                 ec.Emit (OpCodes.Starg_S, (byte) arg_idx);
 631                         else
 632                                 ec.Emit (OpCodes.Starg, arg_idx);
 633                 }
 634
 635                 public void EmitAddressOf (EmitContext ec)
 636                 {
 637                         int arg_idx = idx;
 638
 639                         if (!ec.IsStatic)
 640                                 arg_idx++;
 641
 642                         bool is_ref = (ModFlags & Modifier.ISBYREF) != 0;
 643                         if (is_ref) {
 644                                 ParameterReference.EmitLdArg (ec, arg_idx);
 645                         } else {
 646                                 if (arg_idx <= 255)
 647                                         ec.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
 648                                 else
 649                                         ec.Emit (OpCodes.Ldarga, arg_idx);
 650                         }
 651                 }
 652
 653                 public TemporaryVariableReference ExpressionTreeVariableReference ()
 654                 {
 655                         return expr_tree_variable;
 656                 }
 657
 658                 //
 659                 // System.Linq.Expressions.ParameterExpression type
 660                 //
 661                 public static TypeExpr ResolveParameterExpressionType (IMemberContext ec, Location location)
 662                 {
 663                         TypeSpec p_type = ec.Module.PredefinedTypes.ParameterExpression.Resolve ();
 664                         return new TypeExpression (p_type, location);
 665                 }
 666
 667                 public void Warning_UselessOptionalParameter (Report Report)
 668                 {
 669                         Report.Warning (1066, 1, Location,
 670                                 "The default value specified for optional parameter `{0}' will never be used",
 671                                 Name);
 672                 }
 673         }
 674
 675         //
 676         // Imported or resolved parameter information
 677         //
 678         public class ParameterData : IParameterData
 679         {
 680                 readonly string name;
 681                 readonly Parameter.Modifier modifiers;
 682                 readonly Expression default_value;
 683
 684                 public ParameterData (string name, Parameter.Modifier modifiers)
 685                 {
 686                         this.name = name;
 687                         this.modifiers = modifiers;
 688                 }
 689
 690                 public ParameterData (string name, Parameter.Modifier modifiers, Expression defaultValue)
 691                         : this (name, modifiers)
 692                 {
 693                         this.default_value = defaultValue;
 694                 }
 695
 696                 #region IParameterData Members
 697
 698                 public Expression DefaultValue {
 699                         get { return default_value; }
 700                 }
 701
 702                 public bool HasExtensionMethodModifier {
 703                         get { return (modifiers & Parameter.Modifier.This) != 0; }
 704                 }
 705
 706                 public bool HasDefaultValue {
 707                         get { return default_value != null; }
 708                 }
 709
 710                 public Parameter.Modifier ModFlags {
 711                         get { return modifiers & ~Parameter.Modifier.This; }
 712                 }
 713
 714                 public string Name {
 715                         get { return name; }
 716                 }
 717
 718                 #endregion
 719         }
 720
 721         public abstract class AParametersCollection
 722         {
 723                 protected bool has_arglist;
 724                 protected bool has_params;
 725
 726                 // Null object pattern
 727                 protected IParameterData [] parameters;
 728                 protected TypeSpec [] types;
 729
 730                 public CallingConventions CallingConvention {
 731                         get {
 732                                 return has_arglist ?
 733                                         CallingConventions.VarArgs :
 734                                         CallingConventions.Standard;
 735                         }
 736                 }
 737
 738                 public int Count {
 739                         get { return parameters.Length; }
 740                 }
 741
 742                 public TypeSpec ExtensionMethodType {
 743                         get {
 744                                 if (Count == 0)
 745                                         return null;
 746
 747                                 return FixedParameters [0].HasExtensionMethodModifier ?
 748                                         types [0] : null;
 749                         }
 750                 }
 751
 752                 public IParameterData [] FixedParameters {
 753                         get {
 754                                 return parameters;
 755                         }
 756                 }
 757
 758                 public static ParameterAttributes GetParameterAttribute (Parameter.Modifier modFlags)
 759                 {
 760                         return (modFlags & Parameter.Modifier.OUT) == Parameter.Modifier.OUT ?
 761                                 ParameterAttributes.Out : ParameterAttributes.None;
 762                 }
 763
 764                 // Very expensive operation
 765                 public MetaType[] GetMetaInfo ()
 766                 {
 767                         MetaType[] types;
 768                         if (has_arglist) {
 769                                 if (Count == 1)
 770                                         return MetaType.EmptyTypes;
 771
 772                                 types = new MetaType[Count - 1];
 773                         } else {
 774                                 if (Count == 0)
 775                                         return MetaType.EmptyTypes;
 776
 777                                 types = new MetaType[Count];
 778                         }
 779
 780                         for (int i = 0; i < types.Length; ++i) {
 781                                 types[i] = Types[i].GetMetaInfo ();
 782
 783                                 if ((FixedParameters [i].ModFlags & Parameter.Modifier.ISBYREF) == 0)
 784                                         continue;
 785
 786                                 // TODO MemberCache: Should go to MetaInfo getter
 787                                 types [i] = types [i].MakeByRefType ();
 788                         }
 789
 790                         return types;
 791                 }
 792
 793                 //
 794                 // Returns the parameter information based on the name
 795                 //
 796                 public int GetParameterIndexByName (string name)
 797                 {
 798                         for (int idx = 0; idx < Count; ++idx) {
 799                                 if (parameters [idx].Name == name)
 800                                         return idx;
 801                         }
 802
 803                         return -1;
 804                 }
 805
 806                 public string GetSignatureForDocumentation ()
 807                 {
 808                         if (IsEmpty)
 809                                 return string.Empty;
 810
 811                         StringBuilder sb = new StringBuilder ("(");
 812                         for (int i = 0; i < Count; ++i) {
 813                                 if (i != 0)
 814                                         sb.Append (",");
 815
 816                                 sb.Append (types [i].GetSignatureForDocumentation ());
 817
 818                                 if ((parameters[i].ModFlags & Parameter.Modifier.ISBYREF) != 0)
 819                                         sb.Append ("@");
 820                         }
 821                         sb.Append (")");
 822
 823                         return sb.ToString ();
 824                 }
 825
 826                 public string GetSignatureForError ()
 827                 {
 828                         return GetSignatureForError ("(", ")", Count);
 829                 }
 830
 831                 public string GetSignatureForError (string start, string end, int count)
 832                 {
 833                         StringBuilder sb = new StringBuilder (start);
 834                         for (int i = 0; i < count; ++i) {
 835                                 if (i != 0)
 836                                         sb.Append (", ");
 837                                 sb.Append (ParameterDesc (i));
 838                         }
 839                         sb.Append (end);
 840                         return sb.ToString ();
 841                 }
 842
 843                 public bool HasArglist {
 844                         get { return has_arglist; }
 845                 }
 846
 847                 public bool HasExtensionMethodType {
 848                         get {
 849                                 if (Count == 0)
 850                                         return false;
 851
 852                                 return FixedParameters [0].HasExtensionMethodModifier;
 853                         }
 854                 }
 855
 856                 public bool HasParams {
 857                         get { return has_params; }
 858                 }
 859
 860                 public bool IsEmpty {
 861                         get { return parameters.Length == 0; }
 862                 }
 863
 864                 public AParametersCollection Inflate (TypeParameterInflator inflator)
 865                 {
 866                         TypeSpec[] inflated_types = null;
 867                         bool default_value = false;
 868
 869                         for (int i = 0; i < Count; ++i) {
 870                                 var inflated_param = inflator.Inflate (types[i]);
 871                                 if (inflated_types == null) {
 872                                         if (inflated_param == types[i])
 873                                                 continue;
 874
 875                                         default_value |= FixedParameters[i] is DefaultValueExpression;
 876                                         inflated_types = new TypeSpec[types.Length];
 877                                         Array.Copy (types, inflated_types, types.Length);
 878                                 }
 879
 880                                 inflated_types[i] = inflated_param;
 881                         }
 882
 883                         if (inflated_types == null)
 884                                 return this;
 885
 886                         var clone = (AParametersCollection) MemberwiseClone ();
 887                         clone.types = inflated_types;
 888                         if (default_value) {
 889                                 for (int i = 0; i < Count; ++i) {
 890                                         var dve = clone.FixedParameters[i] as DefaultValueExpression;
 891                                         if (dve != null) {
 892                                                 throw new NotImplementedException ("net");
 893                                                 //      clone.FixedParameters [i].DefaultValue = new DefaultValueExpression ();
 894                                         }
 895                                 }
 896                         }
 897
 898                         return clone;
 899                 }
 900
 901                 public string ParameterDesc (int pos)
 902                 {
 903                         if (types == null || types [pos] == null)
 904                                 return ((Parameter)FixedParameters [pos]).GetSignatureForError ();
 905
 906                         string type = TypeManager.CSharpName (types [pos]);
 907                         if (FixedParameters [pos].HasExtensionMethodModifier)
 908                                 return "this " + type;
 909
 910                         Parameter.Modifier mod = FixedParameters [pos].ModFlags;
 911                         if (mod == 0)
 912                                 return type;
 913
 914                         return Parameter.GetModifierSignature (mod) + " " + type;
 915                 }
 916
 917                 public TypeSpec[] Types {
 918                         get { return types; }
 919                         set { types = value; }
 920                 }
 921         }
 922
 923         //
 924         // A collection of imported or resolved parameters
 925         //
 926         public class ParametersImported : AParametersCollection
 927         {
 928                 public ParametersImported (IParameterData [] parameters, TypeSpec [] types, bool hasArglist, bool hasParams)
 929                 {
 930                         this.parameters = parameters;
 931                         this.types = types;
 932                         this.has_arglist = hasArglist;
 933                         this.has_params = hasParams;
 934                 }
 935
 936                 public ParametersImported (IParameterData[] param, TypeSpec[] types, bool hasParams)
 937                 {
 938                         this.parameters = param;
 939                         this.types = types;
 940                         this.has_params = hasParams;
 941                 }
 942         }
 943
 944         /// <summary>
 945         ///   Represents the methods parameters
 946         /// </summary>
 947         public class ParametersCompiled : AParametersCollection
 948         {
 949                 public static readonly ParametersCompiled EmptyReadOnlyParameters = new ParametersCompiled ();
 950
 951                 // Used by C# 2.0 delegates
 952                 public static readonly ParametersCompiled Undefined = new ParametersCompiled ();
 953
 954                 private ParametersCompiled ()
 955                 {
 956                         parameters = new Parameter [0];
 957                         types = TypeSpec.EmptyTypes;
 958                 }
 959
 960                 private ParametersCompiled (IParameterData[] parameters, TypeSpec[] types)
 961                 {
 962                         this.parameters = parameters;
 963                     this.types = types;
 964                 }
 965
 966                 public ParametersCompiled (params Parameter[] parameters)
 967                 {
 968                         if (parameters == null || parameters.Length == 0)
 969                                 throw new ArgumentException ("Use EmptyReadOnlyParameters");
 970
 971                         this.parameters = parameters;
 972                         int count = parameters.Length;
 973
 974                         for (int i = 0; i < count; i++){
 975                                 has_params |= (parameters [i].ModFlags & Parameter.Modifier.PARAMS) != 0;
 976                         }
 977                 }
 978
 979                 public ParametersCompiled (Parameter [] parameters, bool has_arglist) :
 980                         this (parameters)
 981                 {
 982                         this.has_arglist = has_arglist;
 983                 }
 984
 985                 public static ParametersCompiled CreateFullyResolved (Parameter p, TypeSpec type)
 986                 {
 987                         return new ParametersCompiled (new Parameter [] { p }, new TypeSpec [] { type });
 988                 }
 989
 990                 public static ParametersCompiled CreateFullyResolved (Parameter[] parameters, TypeSpec[] types)
 991                 {
 992                         return new ParametersCompiled (parameters, types);
 993                 }
 994
 995                 //
 996                 // TODO: This does not fit here, it should go to different version of AParametersCollection
 997                 // as the underlying type is not Parameter and some methods will fail to cast
 998                 //
 999                 public static AParametersCollection CreateFullyResolved (params TypeSpec[] types)
1000                 {
1001                         var pd = new ParameterData [types.Length];
1002                         for (int i = 0; i < pd.Length; ++i)
1003                                 pd[i] = new ParameterData (null, Parameter.Modifier.NONE, null);
1004
1005                         return new ParametersCompiled (pd, types);
1006                 }
1007
1008                 public static ParametersCompiled CreateImplicitParameter (FullNamedExpression texpr, Location loc)
1009                 {
1010                         return new ParametersCompiled (
1011                                 new[] { new Parameter (texpr, "value", Parameter.Modifier.NONE, null, loc) },
1012                                 null);
1013                 }
1014
1015                 public void CheckConstraints (IMemberContext mc)
1016                 {
1017                         foreach (Parameter p in parameters) {
1018                                 //
1019                                 // It's null for compiler generated types or special types like __arglist
1020                                 //
1021                                 if (p.TypeExpression != null)
1022                                         ConstraintChecker.Check (mc, p.Type, p.TypeExpression.Location);
1023                         }
1024                 }
1025
1026                 //
1027                 // Returns non-zero value for equal CLS parameter signatures
1028                 //
1029                 public static int IsSameClsSignature (AParametersCollection a, AParametersCollection b)
1030                 {
1031                         int res = 0;
1032
1033                         for (int i = 0; i < a.Count; ++i) {
1034                                 var a_type = a.Types[i];
1035                                 var b_type = b.Types[i];
1036                                 if (TypeSpecComparer.Override.IsEqual (a_type, b_type)) {
1037                                         const Parameter.Modifier ref_out = Parameter.Modifier.REF | Parameter.Modifier.OUT;
1038                                         if ((a.FixedParameters[i].ModFlags & ref_out) != (b.FixedParameters[i].ModFlags & ref_out))
1039                                                 res |= 1;
1040
1041                                         continue;
1042                                 }
1043
1044                                 var ac_a = a_type as ArrayContainer;
1045                                 if (ac_a == null)
1046                                         return 0;
1047
1048                                 var ac_b = b_type as ArrayContainer;
1049                                 if (ac_b == null)
1050                                         return 0;
1051
1052                                 if (ac_a.Element is ArrayContainer || ac_b.Element is ArrayContainer) {
1053                                         res |= 2;
1054                                         continue;
1055                                 }
1056
1057                                 if (ac_a.Rank != ac_b.Rank && TypeSpecComparer.Override.IsEqual (ac_a.Element, ac_b.Element)) {
1058                                         res |= 1;
1059                                         continue;
1060                                 }
1061
1062                                 return 0;
1063                         }
1064
1065                         return res;
1066                 }
1067
1068                 public static ParametersCompiled MergeGenerated (CompilerContext ctx, ParametersCompiled userParams, bool checkConflicts, Parameter compilerParams, TypeSpec compilerTypes)
1069                 {
1070                         return MergeGenerated (ctx, userParams, checkConflicts,
1071                                 new Parameter [] { compilerParams },
1072                                 new TypeSpec [] { compilerTypes });
1073                 }
1074
1075                 //
1076                 // Use this method when you merge compiler generated parameters with user parameters
1077                 //
1078                 public static ParametersCompiled MergeGenerated (CompilerContext ctx, ParametersCompiled userParams, bool checkConflicts, Parameter[] compilerParams, TypeSpec[] compilerTypes)
1079                 {
1080                         Parameter[] all_params = new Parameter [userParams.Count + compilerParams.Length];
1081                         userParams.FixedParameters.CopyTo(all_params, 0);
1082
1083                         TypeSpec [] all_types;
1084                         if (userParams.types != null) {
1085                                 all_types = new TypeSpec [all_params.Length];
1086                                 userParams.Types.CopyTo (all_types, 0);
1087                         } else {
1088                                 all_types = null;
1089                         }
1090
1091                         int last_filled = userParams.Count;
1092                         int index = 0;
1093                         foreach (Parameter p in compilerParams) {
1094                                 for (int i = 0; i < last_filled; ++i) {
1095                                         while (p.Name == all_params [i].Name) {
1096                                                 if (checkConflicts && i < userParams.Count) {
1097                                                         ctx.Report.Error (316, userParams[i].Location,
1098                                                                 "The parameter name `{0}' conflicts with a compiler generated name", p.Name);
1099                                                 }
1100                                                 p.Name = '_' + p.Name;
1101                                         }
1102                                 }
1103                                 all_params [last_filled] = p;
1104                                 if (all_types != null)
1105                                         all_types [last_filled] = compilerTypes [index++];
1106                                 ++last_filled;
1107                         }
1108
1109                         ParametersCompiled parameters = new ParametersCompiled (all_params, all_types);
1110                         parameters.has_params = userParams.has_params;
1111                         return parameters;
1112                 }
1113
1114                 //
1115                 // Parameters checks for members which don't have a block
1116                 //
1117                 public void CheckParameters (MemberCore member)
1118                 {
1119                         for (int i = 0; i < parameters.Length; ++i) {
1120                                 var name = parameters[i].Name;
1121                                 for (int ii = i + 1; ii < parameters.Length; ++ii) {
1122                                         if (parameters[ii].Name == name)
1123                                                 this[ii].Error_DuplicateName (member.Compiler.Report);
1124                                 }
1125                         }
1126                 }
1127
1128                 public bool Resolve (IMemberContext ec)
1129                 {
1130                         if (types != null)
1131                                 return true;
1132
1133                         types = new TypeSpec [Count];
1134
1135                         bool ok = true;
1136                         Parameter p;
1137                         for (int i = 0; i < FixedParameters.Length; ++i) {
1138                                 p = this [i];
1139                                 TypeSpec t = p.Resolve (ec, i);
1140                                 if (t == null) {
1141                                         ok = false;
1142                                         continue;
1143                                 }
1144
1145                                 types [i] = t;
1146                         }
1147
1148                         return ok;
1149                 }
1150
1151                 public void ResolveDefaultValues (MemberCore m)
1152                 {
1153                         ResolveContext rc = null;
1154                         for (int i = 0; i < parameters.Length; ++i) {
1155                                 Parameter p = (Parameter) parameters [i];
1156
1157                                 //
1158                                 // Try not to enter default values resolution if there are is not any default value possible
1159                                 //
1160                                 if (p.HasDefaultValue || p.OptAttributes != null) {
1161                                         if (rc == null)
1162                                                 rc = new ResolveContext (m);
1163
1164                                         p.ResolveDefaultValue (rc);
1165                                 }
1166                         }
1167                 }
1168
1169                 // Define each type attribute (in/out/ref) and
1170                 // the argument names.
1171                 public void ApplyAttributes (IMemberContext mc, MethodBase builder)
1172                 {
1173                         if (Count == 0)
1174                                 return;
1175
1176                         MethodBuilder mb = builder as MethodBuilder;
1177                         ConstructorBuilder cb = builder as ConstructorBuilder;
1178                         var pa = mc.Module.PredefinedAttributes;
1179
1180                         for (int i = 0; i < Count; i++) {
1181                                 this [i].ApplyAttributes (mb, cb, i + 1, pa);
1182                         }
1183                 }
1184
1185                 public void VerifyClsCompliance (IMemberContext ctx)
1186                 {
1187                         foreach (Parameter p in FixedParameters)
1188                                 p.IsClsCompliant (ctx);
1189                 }
1190
1191                 public Parameter this [int pos] {
1192                         get { return (Parameter) parameters [pos]; }
1193                 }
1194
1195                 public Expression CreateExpressionTree (BlockContext ec, Location loc)
1196                 {
1197                         var initializers = new ArrayInitializer (Count, loc);
1198                         foreach (Parameter p in FixedParameters) {
1199                                 //
1200                                 // Each parameter expression is stored to local variable
1201                                 // to save some memory when referenced later.
1202                                 //
1203                                 StatementExpression se = new StatementExpression (p.CreateExpressionTreeVariable (ec));
1204                                 if (se.Resolve (ec)) {
1205                                         ec.CurrentBlock.AddScopeStatement (new TemporaryVariableReference.Declarator (p.ExpressionTreeVariableReference ()));
1206                                         ec.CurrentBlock.AddScopeStatement (se);
1207                                 }
1208
1209                                 initializers.Add (p.ExpressionTreeVariableReference ());
1210                         }
1211
1212                         return new ArrayCreation (
1213                                 Parameter.ResolveParameterExpressionType (ec, loc),
1214                                 initializers, loc);
1215                 }
1216
1217                 public ParametersCompiled Clone ()
1218                 {
1219                         ParametersCompiled p = (ParametersCompiled) MemberwiseClone ();
1220
1221                         p.parameters = new IParameterData [parameters.Length];
1222                         for (int i = 0; i < Count; ++i)
1223                                 p.parameters [i] = this [i].Clone ();
1224
1225                         return p;
1226                 }
1227         }
1228
1229         //
1230         // Default parameter value expression. We need this wrapper to handle
1231         // default parameter values of folded constants when for indexer parameters
1232         // The expression is resolved only once but applied to two methods which
1233         // both share reference to this expression and we ensure that resolving
1234         // this expression always returns same instance
1235         //
1236         public class DefaultParameterValueExpression : CompositeExpression
1237         {
1238                 public DefaultParameterValueExpression (Expression expr)
1239                         : base (expr)
1240                 {
1241                 }
1242
1243                 protected override Expression DoResolve (ResolveContext rc)
1244                 {
1245                         return base.DoResolve (rc);
1246                 }
1247
1248                 public void Resolve (ResolveContext rc, Parameter p)
1249                 {
1250                         var expr = Resolve (rc);
1251                         if (expr == null)
1252                                 return;
1253
1254                         expr = Child;
1255
1256                         if (!(expr is Constant || expr is DefaultValueExpression || (expr is New && ((New) expr).IsDefaultStruct))) {
1257                                 rc.Report.Error (1736, Location,
1258                                         "The expression being assigned to optional parameter `{0}' must be a constant or default value",
1259                                         p.Name);
1260
1261                                 return;
1262                         }
1263
1264                         var parameter_type = p.Type;
1265                         if (type == parameter_type)
1266                                 return;
1267
1268                         var res = Convert.ImplicitConversionStandard (rc, expr, parameter_type, Location);
1269                         if (res != null) {
1270                                 if (parameter_type.IsNullableType && res is Nullable.Wrap) {
1271                                         Nullable.Wrap wrap = (Nullable.Wrap) res;
1272                                         res = wrap.Child;
1273                                         if (!(res is Constant)) {
1274                                                 rc.Report.Error (1770, Location,
1275                                                         "The expression being assigned to nullable optional parameter `{0}' must be default value",
1276                                                         p.Name);
1277                                                 return;
1278                                         }
1279                                 }
1280
1281                                 if (!expr.IsNull && TypeSpec.IsReferenceType (parameter_type) && parameter_type.BuiltinType != BuiltinTypeSpec.Type.String) {
1282                                         rc.Report.Error (1763, Location,
1283                                                 "Optional parameter `{0}' of type `{1}' can only be initialized with `null'",
1284                                                 p.Name, parameter_type.GetSignatureForError ());
1285
1286                                         return;
1287                                 }
1288
1289                                 this.expr = res;
1290                                 return;
1291                         }
1292
1293                         rc.Report.Error (1750, Location,
1294                                 "Optional parameter expression of type `{0}' cannot be converted to parameter type `{1}'",
1295                                 type.GetSignatureForError (), parameter_type.GetSignatureForError ());
1296                 }
1297         }
1298 }