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.Reflection;
  15 using System.Reflection.Emit;
  16 using System.Text;
  17 using System.Linq;
  18
  19 namespace Mono.CSharp {
  20
  21         /// <summary>
  22         ///   Abstract Base class for parameters of a method.
  23         /// </summary>
  24         public abstract class ParameterBase : Attributable
  25         {
  26                 protected ParameterBuilder builder;
  27
  28                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
  29                 {
  30 #if false
  31                         if (a.Type == pa.MarshalAs) {
  32                                 UnmanagedMarshal marshal = a.GetMarshal (this);
  33                                 if (marshal != null) {
  34                                         builder.SetMarshal (marshal);
  35                                 }
  36                                 return;
  37                         }
  38 #endif
  39                         if (a.HasSecurityAttribute) {
  40                                 a.Error_InvalidSecurityParent ();
  41                                 return;
  42                         }
  43
  44                         if (a.Type == pa.Dynamic) {
  45                                 a.Error_MisusedDynamicAttribute ();
  46                                 return;
  47                         }
  48
  49                         builder.SetCustomAttribute ((ConstructorInfo) ctor.GetMetaInfo (), cdata);
  50                 }
  51
  52                 public ParameterBuilder Builder {
  53                         get {
  54                                 return builder;
  55                         }
  56                 }
  57
  58                 public override bool IsClsComplianceRequired()
  59                 {
  60                         return false;
  61                 }
  62         }
  63
  64         /// <summary>
  65         /// Class for applying custom attributes on the return type
  66         /// </summary>
  67         public class ReturnParameter : ParameterBase
  68         {
  69                 MemberCore method;
  70
  71                 // TODO: merge method and mb
  72                 public ReturnParameter (MemberCore method, MethodBuilder mb, Location location)
  73                 {
  74                         this.method = method;
  75                         try {
  76                                 builder = mb.DefineParameter (0, ParameterAttributes.None, "");
  77                         }
  78                         catch (ArgumentOutOfRangeException) {
  79                                 method.Compiler.Report.RuntimeMissingSupport (location, "custom attributes on the return type");
  80                         }
  81                 }
  82
  83                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
  84                 {
  85                         if (a.Type == pa.CLSCompliant) {
  86                                 method.Compiler.Report.Warning (3023, 1, a.Location,
  87                                         "CLSCompliant attribute has no meaning when applied to return types. Try putting it on the method instead");
  88                         }
  89
  90                         // This occurs after Warning -28
  91                         if (builder == null)
  92                                 return;
  93
  94                         base.ApplyAttributeBuilder (a, ctor, cdata, pa);
  95                 }
  96
  97                 public override AttributeTargets AttributeTargets {
  98                         get {
  99                                 return AttributeTargets.ReturnValue;
 100                         }
 101                 }
 102
 103                 /// <summary>
 104                 /// Is never called
 105                 /// </summary>
 106                 public override string[] ValidAttributeTargets {
 107                         get {
 108                                 return null;
 109                         }
 110                 }
 111         }
 112
 113         /// <summary>
 114         /// Class for applying custom attributes on the implicit parameter type
 115         /// of the 'set' method in properties, and the 'add' and 'remove' methods in events.
 116         /// </summary>
 117         ///
 118         // TODO: should use more code from Parameter.ApplyAttributeBuilder
 119         public class ImplicitParameter : ParameterBase {
 120                 public ImplicitParameter (MethodBuilder mb)
 121                 {
 122                         builder = mb.DefineParameter (1, ParameterAttributes.None, "value");
 123                 }
 124
 125                 public override AttributeTargets AttributeTargets {
 126                         get {
 127                                 return AttributeTargets.Parameter;
 128                         }
 129                 }
 130
 131                 /// <summary>
 132                 /// Is never called
 133                 /// </summary>
 134                 public override string[] ValidAttributeTargets {
 135                         get {
 136                                 return null;
 137                         }
 138                 }
 139         }
 140
 141         public class ImplicitLambdaParameter : Parameter
 142         {
 143                 public ImplicitLambdaParameter (string name, Location loc)
 144                         : base (null, name, Modifier.NONE, null, loc)
 145                 {
 146                 }
 147
 148                 public override TypeSpec Resolve (IMemberContext ec, int index)
 149                 {
 150                         if (parameter_type == null)
 151                                 throw new InternalErrorException ("A type of implicit lambda parameter `{0}' is not set",
 152                                         Name);
 153
 154                         base.idx = index;
 155                         return parameter_type;
 156                 }
 157
 158                 public TypeSpec Type {
 159                         set { parameter_type = value; }
 160                 }
 161         }
 162
 163         public class ParamsParameter : Parameter {
 164                 public ParamsParameter (FullNamedExpression type, string name, Attributes attrs, Location loc):
 165                         base (type, name, Parameter.Modifier.PARAMS, attrs, loc)
 166                 {
 167                 }
 168
 169                 public override TypeSpec Resolve (IMemberContext ec, int index)
 170                 {
 171                         if (base.Resolve (ec, index) == null)
 172                                 return null;
 173
 174                         var ac = parameter_type as ArrayContainer;
 175                         if (ac == null || ac.Rank != 1) {
 176                                 ec.Compiler.Report.Error (225, Location, "The params parameter must be a single dimensional array");
 177                                 return null;
 178                         }
 179
 180                         return parameter_type;
 181                 }
 182
 183                 public override void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index)
 184                 {
 185                         base.ApplyAttributes (mb, cb, index);
 186                         PredefinedAttributes.Get.ParamArray.EmitAttribute (builder);
 187                 }
 188         }
 189
 190         public class ArglistParameter : Parameter {
 191                 // Doesn't have proper type because it's never chosen for better conversion
 192                 public ArglistParameter (Location loc) :
 193                         base (null, String.Empty, Parameter.Modifier.NONE, null, loc)
 194                 {
 195                         parameter_type = InternalType.Arglist;
 196                 }
 197
 198                 public override void  ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index)
 199                 {
 200                         // Nothing to do
 201                 }
 202
 203                 public override bool CheckAccessibility (InterfaceMemberBase member)
 204                 {
 205                         return true;
 206                 }
 207
 208                 public override TypeSpec Resolve (IMemberContext ec, int index)
 209                 {
 210                         return parameter_type;
 211                 }
 212         }
 213
 214         public interface IParameterData
 215         {
 216                 Expression DefaultValue { get; }
 217                 bool HasExtensionMethodModifier { get; }
 218                 bool HasDefaultValue { get; }
 219                 Parameter.Modifier ModFlags { get; }
 220                 string Name { get; }
 221         }
 222
 223         //
 224         // Parameter information created by parser
 225         //
 226         public class Parameter : ParameterBase, IParameterData, ILocalVariable {
 227                 [Flags]
 228                 public enum Modifier : byte {
 229                         NONE    = 0,
 230                         REF     = REFMASK | ISBYREF,
 231                         OUT     = OUTMASK | ISBYREF,
 232                         PARAMS  = 4,
 233                         // This is a flag which says that it's either REF or OUT.
 234                         ISBYREF = 8,
 235                         REFMASK = 32,
 236                         OUTMASK = 64,
 237                         This    = 128
 238                 }
 239
 240                 static string[] attribute_targets = new string [] { "param" };
 241
 242                 FullNamedExpression texpr;
 243                 readonly Modifier modFlags;
 244                 string name;
 245                 Expression default_expr;
 246                 protected TypeSpec parameter_type;
 247                 public readonly Location Location;
 248                 protected int idx;
 249                 public bool HasAddressTaken;
 250
 251                 Expression expr_tree_variable;
 252                 static TypeExpr parameter_expr_tree_type;
 253
 254                 HoistedVariable hoisted_variant;
 255
 256                 public Parameter (FullNamedExpression type, string name, Modifier mod, Attributes attrs, Location loc)
 257                 {
 258                         this.name = name;
 259                         modFlags = mod;
 260                         Location = loc;
 261                         texpr = type;
 262
 263                         // Only assign, attributes will be attached during resolve
 264                         base.attributes = attrs;
 265                 }
 266
 267 #region Properties
 268                 public FullNamedExpression TypeExpression  {
 269                         get {
 270                                 return texpr;
 271                         }
 272                 }
 273 #endregion
 274
 275                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
 276                 {
 277                         if (a.Type == pa.In && ModFlags == Modifier.OUT) {
 278                                 a.Report.Error (36, a.Location, "An out parameter cannot have the `In' attribute");
 279                                 return;
 280                         }
 281
 282                         if (a.Type == pa.ParamArray) {
 283                                 a.Report.Error (674, a.Location, "Do not use `System.ParamArrayAttribute'. Use the `params' keyword instead");
 284                                 return;
 285                         }
 286
 287                         if (a.Type == PredefinedAttributes.Get.Out && (ModFlags & Modifier.REF) == Modifier.REF &&
 288                             !OptAttributes.Contains (pa.In)) {
 289                                 a.Report.Error (662, a.Location,
 290                                         "Cannot specify only `Out' attribute on a ref parameter. Use both `In' and `Out' attributes or neither");
 291                                 return;
 292                         }
 293
 294                         if (a.Type == pa.CLSCompliant) {
 295                                 a.Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
 296                         }
 297
 298                         if (HasDefaultValue && (a.Type == pa.DefaultParameterValue || a.Type == pa.OptionalParameter)) {
 299                                 a.Report.Error (1745, a.Location,
 300                                         "Cannot specify `{0}' attribute on optional parameter `{1}'",
 301                                         TypeManager.CSharpName (a.Type).Replace ("Attribute", ""), Name);
 302                                 return;
 303                         }
 304
 305                         if (a.Type == pa.DefaultParameterValue) {
 306                                 TypeSpec arg_type;
 307                                 var c = a.GetParameterDefaultValue (out arg_type);
 308                                 if (c == null) {
 309                                         if (parameter_type == TypeManager.object_type) {
 310                                                 a.Report.Error (1910, a.Location, "Argument of type `{0}' is not applicable for the DefaultParameterValue attribute",
 311                                                         arg_type.GetSignatureForError ());
 312                                         } else {
 313                                                 a.Report.Error (1909, a.Location, "The DefaultParameterValue attribute is not applicable on parameters of type `{0}'",
 314                                                         parameter_type.GetSignatureForError ()); ;
 315                                         }
 316
 317                                         return;
 318                                 }
 319
 320                                 if (arg_type == parameter_type || parameter_type == TypeManager.object_type ||
 321                                         (c.IsNull && TypeManager.IsReferenceType (parameter_type) && !TypeManager.IsGenericParameter (parameter_type)))
 322                                         builder.SetConstant (c.GetValue ());
 323                                 else
 324                                         a.Report.Error (1908, a.Location, "The type of the default value should match the type of the parameter");
 325
 326                                 return;
 327                         }
 328
 329                         base.ApplyAttributeBuilder (a, ctor, cdata, pa);
 330                 }
 331
 332                 public virtual bool CheckAccessibility (InterfaceMemberBase member)
 333                 {
 334                         if (parameter_type == null || TypeManager.IsGenericParameter (parameter_type))
 335                                 return true;
 336
 337                         return member.IsAccessibleAs (parameter_type);
 338                 }
 339
 340                 public static void Reset ()
 341                 {
 342                         parameter_expr_tree_type = null;
 343                 }
 344
 345                 // <summary>
 346                 //   Resolve is used in method definitions
 347                 // </summary>
 348                 public virtual TypeSpec Resolve (IMemberContext rc, int index)
 349                 {
 350                         if (parameter_type != null)
 351                                 return parameter_type;
 352
 353                         if (attributes != null)
 354                                 attributes.AttachTo (this, rc);
 355
 356                         var expr = texpr.ResolveAsTypeTerminal (rc, false);
 357                         if (expr == null)
 358                                 return null;
 359
 360                         this.idx = index;
 361                         texpr = expr;
 362                         parameter_type = texpr.Type;
 363
 364                         // Ignore all checks for dummy members
 365                         AbstractPropertyEventMethod pem = rc as AbstractPropertyEventMethod;
 366                         if (pem != null && pem.IsDummy)
 367                                 return parameter_type;
 368
 369                         if ((modFlags & Parameter.Modifier.ISBYREF) != 0 &&
 370                                 TypeManager.IsSpecialType (parameter_type)) {
 371                                 rc.Compiler.Report.Error (1601, Location, "Method or delegate parameter cannot be of type `{0}'",
 372                                         GetSignatureForError ());
 373                                 return null;
 374                         }
 375
 376                         TypeManager.CheckTypeVariance (parameter_type,
 377                                 (modFlags & Parameter.Modifier.ISBYREF) != 0 ? Variance.None : Variance.Contravariant,
 378                                 rc);
 379
 380                         if (parameter_type.IsStatic) {
 381                                 rc.Compiler.Report.Error (721, Location, "`{0}': static types cannot be used as parameters",
 382                                         texpr.GetSignatureForError ());
 383                                 return parameter_type;
 384                         }
 385
 386                         if ((modFlags & Modifier.This) != 0 && (parameter_type.IsPointer || parameter_type == InternalType.Dynamic)) {
 387                                 rc.Compiler.Report.Error (1103, Location, "The extension method cannot be of type `{0}'",
 388                                         TypeManager.CSharpName (parameter_type));
 389                         }
 390
 391                         return parameter_type;
 392                 }
 393
 394                 public void ResolveDefaultValue (ResolveContext rc)
 395                 {
 396                         if (default_expr != null)
 397                                 default_expr = ResolveDefaultExpression (rc);
 398                 }
 399
 400                 Expression ResolveDefaultExpression (ResolveContext rc)
 401                 {
 402                         default_expr = default_expr.Resolve (rc);
 403                         if (default_expr == null)
 404                                 return null;
 405
 406                         if (!(default_expr is Constant || default_expr is DefaultValueExpression)) {
 407                                 if (TypeManager.IsNullableType (parameter_type)) {
 408                                         rc.Compiler.Report.Error (1770, default_expr.Location,
 409                                                 "The expression being assigned to nullable optional parameter `{0}' must be default value",
 410                                                 Name);
 411                                 } else {
 412                                         rc.Compiler.Report.Error (1736, default_expr.Location,
 413                                                 "The expression being assigned to optional parameter `{0}' must be a constant or default value",
 414                                                 Name);
 415                                 }
 416
 417                                 return null;
 418                         }
 419
 420                         if (TypeManager.IsEqual (default_expr.Type, parameter_type))
 421                                 return default_expr;
 422
 423                         if (TypeManager.IsNullableType (parameter_type)) {
 424                                 if (Convert.ImplicitNulableConversion (rc, default_expr, parameter_type) != null)
 425                                         return default_expr;
 426                         } else {
 427                                 var res = Convert.ImplicitConversionStandard (rc, default_expr, parameter_type, default_expr.Location);
 428                                 if (res != null) {
 429                                         if (!default_expr.IsNull && TypeManager.IsReferenceType (parameter_type) && parameter_type != TypeManager.string_type) {
 430                                                 rc.Compiler.Report.Error (1763, default_expr.Location,
 431                                                         "Optional parameter `{0}' of type `{1}' can only be initialized with `null'",
 432                                                         Name, GetSignatureForError ());
 433
 434                                                 return null;
 435                                         }
 436
 437                                         return res;
 438                                 }
 439                         }
 440
 441                         rc.Compiler.Report.Error (1750, Location,
 442                                 "Optional parameter expression of type `{0}' cannot be converted to parameter type `{1}'",
 443                                 TypeManager.CSharpName (default_expr.Type), GetSignatureForError ());
 444
 445                         return null;
 446                 }
 447
 448                 public bool HasDefaultValue {
 449                         get { return default_expr != null; }
 450                 }
 451
 452                 public bool HasExtensionMethodModifier {
 453                         get { return (modFlags & Modifier.This) != 0; }
 454                 }
 455
 456                 //
 457                 // Hoisted parameter variant
 458                 //
 459                 public HoistedVariable HoistedVariant {
 460                         get {
 461                                 return hoisted_variant;
 462                         }
 463                         set {
 464                                 hoisted_variant = value;
 465                         }
 466                 }
 467
 468                 public Modifier ModFlags {
 469                         get { return modFlags & ~Modifier.This; }
 470                 }
 471
 472                 public string Name {
 473                         get { return name; }
 474                         set { name = value; }
 475                 }
 476
 477                 ParameterAttributes Attributes {
 478                         get { return ParametersCompiled.GetParameterAttribute (modFlags) |
 479                                 (HasDefaultValue ? ParameterAttributes.Optional : ParameterAttributes.None); }
 480                 }
 481
 482                 public override AttributeTargets AttributeTargets {
 483                         get {
 484                                 return AttributeTargets.Parameter;
 485                         }
 486                 }
 487
 488                 public virtual string GetSignatureForError ()
 489                 {
 490                         string type_name;
 491                         if (parameter_type != null)
 492                                 type_name = TypeManager.CSharpName (parameter_type);
 493                         else
 494                                 type_name = texpr.GetSignatureForError ();
 495
 496                         string mod = GetModifierSignature (modFlags);
 497                         if (mod.Length > 0)
 498                                 return String.Concat (mod, " ", type_name);
 499
 500                         return type_name;
 501                 }
 502
 503                 public static string GetModifierSignature (Modifier mod)
 504                 {
 505                         switch (mod) {
 506                         case Modifier.OUT:
 507                                 return "out";
 508                         case Modifier.PARAMS:
 509                                 return "params";
 510                         case Modifier.REF:
 511                                 return "ref";
 512                         case Modifier.This:
 513                                 return "this";
 514                         default:
 515                                 return "";
 516                         }
 517                 }
 518
 519                 public void IsClsCompliant (IMemberContext ctx)
 520                 {
 521                         if (parameter_type.IsCLSCompliant ())
 522                                 return;
 523
 524                         ctx.Compiler.Report.Warning (3001, 1, Location,
 525                                 "Argument type `{0}' is not CLS-compliant", GetSignatureForError ());
 526                 }
 527
 528                 public virtual void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index)
 529                 {
 530                         if (mb == null)
 531                                 builder = cb.DefineParameter (index, Attributes, Name);
 532                         else
 533                                 builder = mb.DefineParameter (index, Attributes, Name);
 534
 535                         if (OptAttributes != null)
 536                                 OptAttributes.Emit ();
 537
 538                         if (HasDefaultValue) {
 539                                 //
 540                                 // Emit constant values for true constants only, the other
 541                                 // constant-like expressions will rely on default value expression
 542                                 //
 543                                 Constant c = default_expr as Constant;
 544                                 if (c != null) {
 545                                         if (default_expr.Type == TypeManager.decimal_type) {
 546                                                 builder.SetCustomAttribute (Const.CreateDecimalConstantAttribute (c));
 547                                         } else {
 548                                                 builder.SetConstant (c.GetTypedValue ());
 549                                         }
 550                                 }
 551                         }
 552
 553                         if (parameter_type == InternalType.Dynamic) {
 554                                 PredefinedAttributes.Get.Dynamic.EmitAttribute (builder);
 555                         } else {
 556                                 var trans_flags = TypeManager.HasDynamicTypeUsed (parameter_type);
 557                                 if (trans_flags != null) {
 558                                         var pa = PredefinedAttributes.Get.DynamicTransform;
 559                                         if (pa.Constructor != null || pa.ResolveConstructor (Location, ArrayContainer.MakeType (TypeManager.bool_type))) {
 560                                                 builder.SetCustomAttribute (
 561                                                         new CustomAttributeBuilder (pa.Constructor, new object [] { trans_flags }));
 562                                         }
 563                                 }
 564                         }
 565                 }
 566
 567                 public override string[] ValidAttributeTargets {
 568                         get {
 569                                 return attribute_targets;
 570                         }
 571                 }
 572
 573                 public Parameter Clone ()
 574                 {
 575                         Parameter p = (Parameter) MemberwiseClone ();
 576                         if (attributes != null)
 577                                 p.attributes = attributes.Clone ();
 578
 579                         return p;
 580                 }
 581
 582                 public ExpressionStatement CreateExpressionTreeVariable (BlockContext ec)
 583                 {
 584                         if ((modFlags & Modifier.ISBYREF) != 0)
 585                                 ec.Report.Error (1951, Location, "An expression tree parameter cannot use `ref' or `out' modifier");
 586
 587                         expr_tree_variable = new TemporaryVariable (ResolveParameterExpressionType (ec, Location).Type, Location);
 588                         expr_tree_variable = expr_tree_variable.Resolve (ec);
 589
 590                         Arguments arguments = new Arguments (2);
 591                         arguments.Add (new Argument (new TypeOf (
 592                                 new TypeExpression (parameter_type, Location), Location)));
 593                         arguments.Add (new Argument (new StringConstant (Name, Location)));
 594                         return new SimpleAssign (ExpressionTreeVariableReference (),
 595                                 Expression.CreateExpressionFactoryCall (ec, "Parameter", null, arguments, Location));
 596                 }
 597
 598                 public Expression DefaultValue {
 599                         get { return default_expr; }
 600                         set { default_expr = value; }
 601                 }
 602
 603                 public void Emit (EmitContext ec)
 604                 {
 605                         int arg_idx = idx;
 606                         if (!ec.IsStatic)
 607                                 arg_idx++;
 608
 609                         ParameterReference.EmitLdArg (ec, arg_idx);
 610                 }
 611
 612                 public void EmitAssign (EmitContext ec)
 613                 {
 614                         int arg_idx = idx;
 615                         if (!ec.IsStatic)
 616                                 arg_idx++;
 617
 618                         if (arg_idx <= 255)
 619                                 ec.Emit (OpCodes.Starg_S, (byte) arg_idx);
 620                         else
 621                                 ec.Emit (OpCodes.Starg, arg_idx);
 622                 }
 623
 624                 public void EmitAddressOf (EmitContext ec)
 625                 {
 626                         int arg_idx = idx;
 627
 628                         if (!ec.IsStatic)
 629                                 arg_idx++;
 630
 631                         bool is_ref = (ModFlags & Modifier.ISBYREF) != 0;
 632                         if (is_ref) {
 633                                 ParameterReference.EmitLdArg (ec, arg_idx);
 634                         } else {
 635                                 if (arg_idx <= 255)
 636                                         ec.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
 637                                 else
 638                                         ec.Emit (OpCodes.Ldarga, arg_idx);
 639                         }
 640                 }
 641
 642                 public Expression ExpressionTreeVariableReference ()
 643                 {
 644                         return expr_tree_variable;
 645                 }
 646
 647                 //
 648                 // System.Linq.Expressions.ParameterExpression type
 649                 //
 650                 public static TypeExpr ResolveParameterExpressionType (IMemberContext ec, Location location)
 651                 {
 652                         if (parameter_expr_tree_type != null)
 653                                 return parameter_expr_tree_type;
 654
 655                         TypeSpec p_type = TypeManager.parameter_expression_type;
 656                         if (p_type == null) {
 657                                 p_type = TypeManager.CoreLookupType (ec.Compiler, "System.Linq.Expressions", "ParameterExpression", MemberKind.Class, true);
 658                                 TypeManager.parameter_expression_type = p_type;
 659                         }
 660
 661                         parameter_expr_tree_type = new TypeExpression (p_type, location).
 662                                 ResolveAsTypeTerminal (ec, false);
 663
 664                         return parameter_expr_tree_type;
 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 Type[] GetMetaInfo ()
 766                 {
 767                         Type[] types;
 768                         if (has_arglist) {
 769                                 if (Count == 1)
 770                                         return Type.EmptyTypes;
 771
 772                                 types = new Type [Count - 1];
 773                         } else {
 774                                 if (Count == 0)
 775                                         return Type.EmptyTypes;
 776
 777                                 types = new Type [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 GetSignatureForError ()
 807                 {
 808                         return GetSignatureForError ("(", ")", Count);
 809                 }
 810
 811                 public string GetSignatureForError (string start, string end, int count)
 812                 {
 813                         StringBuilder sb = new StringBuilder (start);
 814                         for (int i = 0; i < count; ++i) {
 815                                 if (i != 0)
 816                                         sb.Append (", ");
 817                                 sb.Append (ParameterDesc (i));
 818                         }
 819                         sb.Append (end);
 820                         return sb.ToString ();
 821                 }
 822
 823                 public bool HasArglist {
 824                         get { return has_arglist; }
 825                 }
 826
 827                 public bool HasExtensionMethodType {
 828                         get {
 829                                 if (Count == 0)
 830                                         return false;
 831
 832                                 return FixedParameters [0].HasExtensionMethodModifier;
 833                         }
 834                 }
 835
 836                 public bool HasParams {
 837                         get { return has_params; }
 838                 }
 839
 840                 public bool IsEmpty {
 841                         get { return parameters.Length == 0; }
 842                 }
 843
 844                 public AParametersCollection Inflate (TypeParameterInflator inflator)
 845                 {
 846                         TypeSpec[] inflated_types = null;
 847                         bool default_value = false;
 848
 849                         for (int i = 0; i < Count; ++i) {
 850                                 var inflated_param = inflator.Inflate (types[i]);
 851                                 if (inflated_types == null) {
 852                                         if (inflated_param == types[i])
 853                                                 continue;
 854
 855                                         default_value |= FixedParameters[i] is DefaultValueExpression;
 856                                         inflated_types = new TypeSpec[types.Length];
 857                                         Array.Copy (types, inflated_types, types.Length);
 858                                 }
 859
 860                                 inflated_types[i] = inflated_param;
 861                         }
 862
 863                         if (inflated_types == null)
 864                                 return this;
 865
 866                         var clone = (AParametersCollection) MemberwiseClone ();
 867                         clone.types = inflated_types;
 868                         if (default_value) {
 869                                 for (int i = 0; i < Count; ++i) {
 870                                         var dve = clone.FixedParameters[i] as DefaultValueExpression;
 871                                         if (dve != null) {
 872                                                 throw new NotImplementedException ("net");
 873                                                 //      clone.FixedParameters [i].DefaultValue = new DefaultValueExpression ();
 874                                         }
 875                                 }
 876                         }
 877
 878                         return clone;
 879                 }
 880
 881                 public string ParameterDesc (int pos)
 882                 {
 883                         if (types == null || types [pos] == null)
 884                                 return ((Parameter)FixedParameters [pos]).GetSignatureForError ();
 885
 886                         string type = TypeManager.CSharpName (types [pos]);
 887                         if (FixedParameters [pos].HasExtensionMethodModifier)
 888                                 return "this " + type;
 889
 890                         Parameter.Modifier mod = FixedParameters [pos].ModFlags;
 891                         if (mod == 0)
 892                                 return type;
 893
 894                         return Parameter.GetModifierSignature (mod) + " " + type;
 895                 }
 896
 897                 public TypeSpec[] Types {
 898                         get { return types; }
 899                         set { types = value; }
 900                 }
 901         }
 902
 903         //
 904         // A collection of imported or resolved parameters
 905         //
 906         public class ParametersImported : AParametersCollection
 907         {
 908                 ParametersImported (AParametersCollection param, TypeSpec[] types)
 909                 {
 910                         this.parameters = param.FixedParameters;
 911                         this.types = types;
 912                         has_arglist = param.HasArglist;
 913                         has_params = param.HasParams;
 914                 }
 915
 916                 ParametersImported (IParameterData [] parameters, TypeSpec [] types, bool hasArglist, bool hasParams)
 917                 {
 918                         this.parameters = parameters;
 919                         this.types = types;
 920                         this.has_arglist = hasArglist;
 921                         this.has_params = hasParams;
 922                 }
 923
 924                 public ParametersImported (IParameterData [] param, TypeSpec[] types)
 925                 {
 926                         this.parameters = param;
 927                         this.types = types;
 928                 }
 929
 930                 public static AParametersCollection Create (TypeSpec parent, MethodBase method)
 931                 {
 932                         return Create (parent, method.GetParameters (), method);
 933                 }
 934
 935                 //
 936                 // Imports SRE parameters
 937                 //
 938                 public static AParametersCollection Create (TypeSpec parent, ParameterInfo [] pi, MethodBase method)
 939                 {
 940                         int varargs = method != null && (method.CallingConvention & CallingConventions.VarArgs) != 0 ? 1 : 0;
 941
 942                         if (pi.Length == 0 && varargs == 0)
 943                                 return ParametersCompiled.EmptyReadOnlyParameters;
 944
 945                         TypeSpec [] types = new TypeSpec [pi.Length + varargs];
 946                         IParameterData [] par = new IParameterData [pi.Length + varargs];
 947                         bool is_params = false;
 948                         PredefinedAttribute extension_attr = PredefinedAttributes.Get.Extension;
 949                         for (int i = 0; i < pi.Length; i++) {
 950                                 ParameterInfo p = pi [i];
 951                                 Parameter.Modifier mod = 0;
 952                                 Expression default_value = null;
 953                                 if (p.ParameterType.IsByRef) {
 954                                         if ((p.Attributes & (ParameterAttributes.Out | ParameterAttributes.In)) == ParameterAttributes.Out)
 955                                                 mod = Parameter.Modifier.OUT;
 956                                         else
 957                                                 mod = Parameter.Modifier.REF;
 958
 959                                         //
 960                                         // Strip reference wrapping
 961                                         //
 962                                         types [i] = Import.ImportType (p.ParameterType.GetElementType ());
 963                                 } else if (i == 0 && method.IsStatic && parent.IsStatic &&
 964                                         extension_attr.IsDefined && extension_attr.IsDefined && method.IsDefined (extension_attr.Type.GetMetaInfo (), false)) {
 965                                         mod = Parameter.Modifier.This;
 966                                         types[i] = Import.ImportType (p.ParameterType);
 967                                 } else {
 968                                         types[i] = Import.ImportType (p.ParameterType);
 969
 970                                         if (i >= pi.Length - 2 && types[i] is ArrayContainer) {
 971                                                 var cattrs = CustomAttributeData.GetCustomAttributes (p);
 972                                                 if (cattrs != null && cattrs.Any (l => l.Constructor.DeclaringType == typeof (ParamArrayAttribute))) {
 973                                                         mod = Parameter.Modifier.PARAMS;
 974                                                         is_params = true;
 975                                                 }
 976                                         }
 977
 978                                         if (!is_params && p.IsOptional) {
 979                                                 object value = p.DefaultValue;
 980                                                 if (value == Missing.Value) {
 981                                                         default_value = EmptyExpression.Null;
 982                                                 } else if (value == null) {
 983                                                         default_value = new NullLiteral (Location.Null);
 984                                                 } else {
 985                                                         default_value = Constant.CreateConstant (null, Import.ImportType (value.GetType ()), value, Location.Null);
 986                                                 }
 987                                         }
 988                                 }
 989
 990                                 par [i] = new ParameterData (p.Name, mod, default_value);
 991                         }
 992
 993                         if (varargs != 0) {
 994                                 par [par.Length - 1] = new ArglistParameter (Location.Null);
 995                                 types [types.Length - 1] = InternalType.Arglist;
 996                         }
 997
 998                         return method != null ?
 999                                 new ParametersImported (par, types, varargs != 0, is_params) :
1000                                 new ParametersImported (par, types);
1001                 }
1002         }
1003
1004         /// <summary>
1005         ///   Represents the methods parameters
1006         /// </summary>
1007         public class ParametersCompiled : AParametersCollection
1008         {
1009                 public static readonly ParametersCompiled EmptyReadOnlyParameters = new ParametersCompiled ();
1010
1011                 // Used by C# 2.0 delegates
1012                 public static readonly ParametersCompiled Undefined = new ParametersCompiled ();
1013
1014                 private ParametersCompiled ()
1015                 {
1016                         parameters = new Parameter [0];
1017                         types = TypeSpec.EmptyTypes;
1018                 }
1019
1020                 private ParametersCompiled (IParameterData [] parameters, TypeSpec [] types)
1021                 {
1022                         this.parameters = parameters;
1023                     this.types = types;
1024                 }
1025
1026                 public ParametersCompiled (CompilerContext ctx, params Parameter[] parameters)
1027                 {
1028                         if (parameters == null)
1029                                 throw new ArgumentException ("Use EmptyReadOnlyParameters");
1030
1031                         this.parameters = parameters;
1032                         int count = parameters.Length;
1033
1034                         if (count == 0)
1035                                 return;
1036
1037                         if (count == 1) {
1038                                 has_params = (parameters [0].ModFlags & Parameter.Modifier.PARAMS) != 0;
1039                                 return;
1040                         }
1041
1042                         for (int i = 0; i < count; i++){
1043                                 string base_name = parameters [i].Name;
1044                                 has_params |= (parameters [i].ModFlags & Parameter.Modifier.PARAMS) != 0;
1045
1046                                 for (int j = i + 1; j < count; j++){
1047                                         if (base_name != parameters [j].Name)
1048                                                 continue;
1049
1050                                         ErrorDuplicateName (parameters[i], ctx.Report);
1051                                         i = j;
1052                                 }
1053                         }
1054                 }
1055
1056                 public ParametersCompiled (CompilerContext ctx, Parameter [] parameters, bool has_arglist) :
1057                         this (ctx, parameters)
1058                 {
1059                         this.has_arglist = has_arglist;
1060                 }
1061
1062                 public static ParametersCompiled CreateFullyResolved (Parameter p, TypeSpec type)
1063                 {
1064                         return new ParametersCompiled (new Parameter [] { p }, new TypeSpec [] { type });
1065                 }
1066
1067                 public static ParametersCompiled CreateFullyResolved (IParameterData[] parameters, TypeSpec[] types)
1068                 {
1069                         return new ParametersCompiled (parameters, types);
1070                 }
1071
1072                 public static AParametersCollection CreateFullyResolved (TypeSpec[] types)
1073                 {
1074                         var pd = new ParameterData [types.Length];
1075                         for (int i = 0; i < pd.Length; ++i)
1076                                 pd[i] = new ParameterData (null, Parameter.Modifier.NONE, null);
1077
1078                         return new ParametersCompiled (pd, types);
1079                 }
1080
1081                 //
1082                 // Returns non-zero value for equal CLS parameter signatures
1083                 //
1084                 public static int IsSameClsSignature (AParametersCollection a, AParametersCollection b)
1085                 {
1086                         int res = 0;
1087
1088                         for (int i = 0; i < a.Count; ++i) {
1089                                 var a_type = a.Types[i];
1090                                 var b_type = b.Types[i];
1091                                 if (TypeSpecComparer.Override.IsEqual (a_type, b_type)) {
1092                                         const Parameter.Modifier ref_out = Parameter.Modifier.REF | Parameter.Modifier.OUT;
1093                                         if ((a.FixedParameters[i].ModFlags & ref_out) != (b.FixedParameters[i].ModFlags & ref_out))
1094                                                 res |= 1;
1095
1096                                         continue;
1097                                 }
1098
1099                                 var ac_a = a_type as ArrayContainer;
1100                                 if (ac_a == null)
1101                                         return 0;
1102
1103                                 var ac_b = b_type as ArrayContainer;
1104                                 if (ac_b == null)
1105                                         return 0;
1106
1107                                 if (ac_a.Element is ArrayContainer || ac_b.Element is ArrayContainer) {
1108                                         res |= 2;
1109                                         continue;
1110                                 }
1111
1112                                 if (ac_a.Rank != ac_b.Rank && TypeSpecComparer.Override.IsEqual (ac_a.Element, ac_b.Element)) {
1113                                         res |= 1;
1114                                         continue;
1115                                 }
1116
1117                                 return 0;
1118                         }
1119
1120                         return res;
1121                 }
1122
1123                 public static ParametersCompiled MergeGenerated (CompilerContext ctx, ParametersCompiled userParams, bool checkConflicts, Parameter compilerParams, TypeSpec compilerTypes)
1124                 {
1125                         return MergeGenerated (ctx, userParams, checkConflicts,
1126                                 new Parameter [] { compilerParams },
1127                                 new TypeSpec [] { compilerTypes });
1128                 }
1129
1130                 //
1131                 // Use this method when you merge compiler generated parameters with user parameters
1132                 //
1133                 public static ParametersCompiled MergeGenerated (CompilerContext ctx, ParametersCompiled userParams, bool checkConflicts, Parameter[] compilerParams, TypeSpec[] compilerTypes)
1134                 {
1135                         Parameter[] all_params = new Parameter [userParams.Count + compilerParams.Length];
1136                         userParams.FixedParameters.CopyTo(all_params, 0);
1137
1138                         TypeSpec [] all_types;
1139                         if (userParams.types != null) {
1140                                 all_types = new TypeSpec [all_params.Length];
1141                                 userParams.Types.CopyTo (all_types, 0);
1142                         } else {
1143                                 all_types = null;
1144                         }
1145
1146                         int last_filled = userParams.Count;
1147                         int index = 0;
1148                         foreach (Parameter p in compilerParams) {
1149                                 for (int i = 0; i < last_filled; ++i) {
1150                                         while (p.Name == all_params [i].Name) {
1151                                                 if (checkConflicts && i < userParams.Count) {
1152                                                         ctx.Report.Error (316, userParams[i].Location,
1153                                                                 "The parameter name `{0}' conflicts with a compiler generated name", p.Name);
1154                                                 }
1155                                                 p.Name = '_' + p.Name;
1156                                         }
1157                                 }
1158                                 all_params [last_filled] = p;
1159                                 if (all_types != null)
1160                                         all_types [last_filled] = compilerTypes [index++];
1161                                 ++last_filled;
1162                         }
1163
1164                         ParametersCompiled parameters = new ParametersCompiled (all_params, all_types);
1165                         parameters.has_params = userParams.has_params;
1166                         return parameters;
1167                 }
1168
1169                 protected virtual void ErrorDuplicateName (Parameter p, Report Report)
1170                 {
1171                         Report.Error (100, p.Location, "The parameter name `{0}' is a duplicate", p.Name);
1172                 }
1173
1174                 public bool Resolve (IMemberContext ec)
1175                 {
1176                         if (types != null)
1177                                 return true;
1178
1179                         types = new TypeSpec [Count];
1180
1181                         bool ok = true;
1182                         Parameter p;
1183                         for (int i = 0; i < FixedParameters.Length; ++i) {
1184                                 p = this [i];
1185                                 TypeSpec t = p.Resolve (ec, i);
1186                                 if (t == null) {
1187                                         ok = false;
1188                                         continue;
1189                                 }
1190
1191                                 types [i] = t;
1192                         }
1193
1194                         return ok;
1195                 }
1196
1197                 public void ResolveDefaultValues (ResolveContext rc)
1198                 {
1199                         for (int i = 0; i < FixedParameters.Length; ++i) {
1200                                 this [i].ResolveDefaultValue (rc);
1201                         }
1202                 }
1203
1204                 // Define each type attribute (in/out/ref) and
1205                 // the argument names.
1206                 public void ApplyAttributes (MethodBase builder)
1207                 {
1208                         if (Count == 0)
1209                                 return;
1210
1211                         MethodBuilder mb = builder as MethodBuilder;
1212                         ConstructorBuilder cb = builder as ConstructorBuilder;
1213
1214                         for (int i = 0; i < Count; i++) {
1215                                 this [i].ApplyAttributes (mb, cb, i + 1);
1216                         }
1217                 }
1218
1219                 public void VerifyClsCompliance (IMemberContext ctx)
1220                 {
1221                         foreach (Parameter p in FixedParameters)
1222                                 p.IsClsCompliant (ctx);
1223                 }
1224
1225                 public Parameter this [int pos] {
1226                         get { return (Parameter) parameters [pos]; }
1227                 }
1228
1229                 public Expression CreateExpressionTree (BlockContext ec, Location loc)
1230                 {
1231                         var initializers = new ArrayInitializer (Count, loc);
1232                         foreach (Parameter p in FixedParameters) {
1233                                 //
1234                                 // Each parameter expression is stored to local variable
1235                                 // to save some memory when referenced later.
1236                                 //
1237                                 StatementExpression se = new StatementExpression (p.CreateExpressionTreeVariable (ec));
1238                                 if (se.Resolve (ec))
1239                                         ec.CurrentBlock.AddScopeStatement (se);
1240
1241                                 initializers.Add (p.ExpressionTreeVariableReference ());
1242                         }
1243
1244                         return new ArrayCreation (
1245                                 Parameter.ResolveParameterExpressionType (ec, loc),
1246                                 "[]", initializers, loc);
1247                 }
1248
1249                 public ParametersCompiled Clone ()
1250                 {
1251                         ParametersCompiled p = (ParametersCompiled) MemberwiseClone ();
1252
1253                         p.parameters = new IParameterData [parameters.Length];
1254                         for (int i = 0; i < Count; ++i)
1255                                 p.parameters [i] = this [i].Clone ();
1256
1257                         return p;
1258                 }
1259         }
1260 }