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.Collections;
  17 using System.Text;
  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                 protected ParameterBase (Attributes attrs)
  29                         : base (attrs)
  30                 {
  31                 }
  32
  33                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
  34                 {
  35 #if !NET_2_0
  36                         if (a.Type == TypeManager.marshal_as_attr_type) {
  37                                 UnmanagedMarshal marshal = a.GetMarshal (this);
  38                                 if (marshal != null) {
  39                                         builder.SetMarshal (marshal);
  40                                 }
  41                                 return;
  42                         }
  43 #endif
  44                         if (a.HasSecurityAttribute) {
  45                                 a.Error_InvalidSecurityParent ();
  46                                 return;
  47                         }
  48
  49                         builder.SetCustomAttribute (cb);
  50                 }
  51
  52                 public override bool IsClsComplianceRequired()
  53                 {
  54                         return false;
  55                 }
  56         }
  57
  58         /// <summary>
  59         /// Class for applying custom attributes on the return type
  60         /// </summary>
  61         public class ReturnParameter : ParameterBase {
  62                 public ReturnParameter (MethodBuilder mb, Location location):
  63                         base (null)
  64                 {
  65                         try {
  66                                 builder = mb.DefineParameter (0, ParameterAttributes.None, "");
  67                         }
  68                         catch (ArgumentOutOfRangeException) {
  69                                 Report.RuntimeMissingSupport (location, "custom attributes on the return type");
  70                         }
  71                 }
  72
  73                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  74                 {
  75                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
  76                                 Report.Warning (3023, 1, a.Location, "CLSCompliant attribute has no meaning when applied to return types. Try putting it on the method instead");
  77                         }
  78
  79                         // This occurs after Warning -28
  80                         if (builder == null)
  81                                 return;
  82
  83                         base.ApplyAttributeBuilder (a, cb);
  84                 }
  85
  86                 public override AttributeTargets AttributeTargets {
  87                         get {
  88                                 return AttributeTargets.ReturnValue;
  89                         }
  90                 }
  91
  92                 public override IResolveContext ResolveContext {
  93                         get {
  94                                 throw new NotSupportedException ();
  95                         }
  96                 }
  97
  98                 /// <summary>
  99                 /// Is never called
 100                 /// </summary>
 101                 public override string[] ValidAttributeTargets {
 102                         get {
 103                                 return null;
 104                         }
 105                 }
 106         }
 107
 108         /// <summary>
 109         /// Class for applying custom attributes on the implicit parameter type
 110         /// of the 'set' method in properties, and the 'add' and 'remove' methods in events.
 111         /// </summary>
 112         ///
 113         // TODO: should use more code from Parameter.ApplyAttributeBuilder
 114         public class ImplicitParameter : ParameterBase {
 115                 public ImplicitParameter (MethodBuilder mb):
 116                         base (null)
 117                 {
 118                         builder = mb.DefineParameter (1, ParameterAttributes.None, "");
 119                 }
 120
 121                 public override AttributeTargets AttributeTargets {
 122                         get {
 123                                 return AttributeTargets.Parameter;
 124                         }
 125                 }
 126
 127                 public override IResolveContext ResolveContext {
 128                         get {
 129                                 throw new NotSupportedException ();
 130                         }
 131                 }
 132
 133                 /// <summary>
 134                 /// Is never called
 135                 /// </summary>
 136                 public override string[] ValidAttributeTargets {
 137                         get {
 138                                 return null;
 139                         }
 140                 }
 141         }
 142
 143         public class ImplicitLambdaParameter : Parameter
 144         {
 145                 public ImplicitLambdaParameter (string name, Location loc)
 146                         : base (null, name, Modifier.NONE, null, loc)
 147                 {
 148                 }
 149
 150                 public override Type Resolve (IResolveContext ec)
 151                 {
 152                         if (parameter_type == null)
 153                                 throw new InternalErrorException ("A type of implicit lambda parameter `{0}' is not set",
 154                                         Name);
 155
 156                         return parameter_type;
 157                 }
 158
 159                 public Type Type {
 160                         set { parameter_type = value; }
 161                 }
 162         }
 163
 164         public class ParamsParameter : Parameter {
 165                 public ParamsParameter (FullNamedExpression type, string name, Attributes attrs, Location loc):
 166                         base (type, name, Parameter.Modifier.PARAMS, attrs, loc)
 167                 {
 168                 }
 169
 170                 public override Type Resolve (IResolveContext ec)
 171                 {
 172                         if (base.Resolve (ec) == null)
 173                                 return null;
 174
 175                         if (!parameter_type.IsArray || parameter_type.GetArrayRank () != 1) {
 176                                 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
 187                         CustomAttributeBuilder ca = TypeManager.param_array_attr;
 188                         if (ca == null) {
 189                                 ConstructorInfo ci = TypeManager.GetPredefinedConstructor (TypeManager.param_array_type, Location, Type.EmptyTypes);
 190                                 if (ci == null)
 191                                         return;
 192
 193                                 ca = new CustomAttributeBuilder (ci, new object [0]);
 194                                 if (ca == null)
 195                                         return;
 196
 197                                 TypeManager.param_array_attr = ca;
 198                         }
 199
 200                         builder.SetCustomAttribute (ca);
 201                 }
 202         }
 203
 204         public class ArglistParameter : Parameter {
 205                 // Doesn't have proper type because it's never chosen for better conversion
 206                 public ArglistParameter (Location loc) :
 207                         base (null, String.Empty, Parameter.Modifier.ARGLIST, null, loc)
 208                 {
 209                 }
 210
 211                 public override void  ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index)
 212                 {
 213                         // Nothing to do
 214                 }
 215
 216                 public override bool CheckAccessibility (InterfaceMemberBase member)
 217                 {
 218                         return true;
 219                 }
 220
 221                 public override Type Resolve (IResolveContext ec)
 222                 {
 223                         return typeof (ArglistParameter);
 224                 }
 225
 226                 public override string GetSignatureForError ()
 227                 {
 228                         return "__arglist";
 229                 }
 230         }
 231
 232         public interface IParameterData
 233         {
 234                 bool HasExtensionMethodModifier { get; }
 235                 Parameter.Modifier ModFlags { get; }
 236                 string Name { get; }
 237         }
 238
 239         //
 240         // Parameter information created by parser
 241         //
 242         public class Parameter : ParameterBase, IParameterData, ILocalVariable {
 243                 [Flags]
 244                 public enum Modifier : byte {
 245                         NONE    = 0,
 246                         REF     = REFMASK | ISBYREF,
 247                         OUT     = OUTMASK | ISBYREF,
 248                         PARAMS  = 4,
 249                         // This is a flag which says that it's either REF or OUT.
 250                         ISBYREF = 8,
 251                         ARGLIST = 16,
 252                         REFMASK = 32,
 253                         OUTMASK = 64,
 254                         This    = 128
 255                 }
 256
 257                 static string[] attribute_targets = new string [] { "param" };
 258
 259                 protected FullNamedExpression TypeName;
 260                 readonly Modifier modFlags;
 261                 string name;
 262                 protected Type parameter_type;
 263                 public readonly Location Location;
 264                 int idx;
 265                 public bool HasAddressTaken;
 266
 267                 IResolveContext resolve_context;
 268                 LocalVariableReference expr_tree_variable;
 269                 static TypeExpr parameter_expr_tree_type;
 270
 271                 public HoistedVariable HoistedVariableReference;
 272
 273                 public Parameter (FullNamedExpression type, string name, Modifier mod, Attributes attrs, Location loc)
 274                         : base (attrs)
 275                 {
 276                         if (type == TypeManager.system_void_expr)
 277                                 Report.Error (1536, loc, "Invalid parameter type `void'");
 278
 279                         this.name = name;
 280                         modFlags = mod;
 281                         Location = loc;
 282                         TypeName = type;
 283                 }
 284
 285                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
 286                 {
 287                         if (a.Type == TypeManager.in_attribute_type && ModFlags == Modifier.OUT) {
 288                                 Report.Error (36, a.Location, "An out parameter cannot have the `In' attribute");
 289                                 return;
 290                         }
 291
 292                         if (a.Type == TypeManager.param_array_type) {
 293                                 Report.Error (674, a.Location, "Do not use `System.ParamArrayAttribute'. Use the `params' keyword instead");
 294                                 return;
 295                         }
 296
 297                         if (a.Type == TypeManager.out_attribute_type && (ModFlags & Modifier.REF) == Modifier.REF &&
 298                             TypeManager.in_attribute_type != null && !OptAttributes.Contains (TypeManager.in_attribute_type)) {
 299                                 Report.Error (662, a.Location,
 300                                         "Cannot specify only `Out' attribute on a ref parameter. Use both `In' and `Out' attributes or neither");
 301                                 return;
 302                         }
 303
 304                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
 305                                 Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
 306                         }
 307
 308                         // TypeManager.default_parameter_value_attribute_type is null if !NET_2_0, or if System.dll is not referenced
 309                         if (a.Type == TypeManager.default_parameter_value_attribute_type) {
 310                                 object val = a.GetParameterDefaultValue ();
 311                                 if (val != null) {
 312                                         Type t = val.GetType ();
 313                                         if (t.IsArray || TypeManager.IsSubclassOf (t, TypeManager.type_type)) {
 314                                                 if (parameter_type == TypeManager.object_type) {
 315                                                         if (!t.IsArray)
 316                                                                 t = TypeManager.type_type;
 317
 318                                                         Report.Error (1910, a.Location, "Argument of type `{0}' is not applicable for the DefaultValue attribute",
 319                                                                 TypeManager.CSharpName (t));
 320                                                 } else {
 321                                                         Report.Error (1909, a.Location, "The DefaultValue attribute is not applicable on parameters of type `{0}'",
 322                                                                 TypeManager.CSharpName (parameter_type)); ;
 323                                                 }
 324                                                 return;
 325                                         }
 326                                 }
 327
 328                                 if (parameter_type == TypeManager.object_type ||
 329                                     (val == null && !TypeManager.IsGenericParameter (parameter_type) && TypeManager.IsReferenceType (parameter_type)) ||
 330                                     (val != null && TypeManager.TypeToCoreType (val.GetType ()) == parameter_type))
 331                                         builder.SetConstant (val);
 332                                 else
 333                                         Report.Error (1908, a.Location, "The type of the default value should match the type of the parameter");
 334                                 return;
 335                         }
 336
 337                         base.ApplyAttributeBuilder (a, cb);
 338                 }
 339
 340                 public virtual bool CheckAccessibility (InterfaceMemberBase member)
 341                 {
 342                         if (parameter_type == null || TypeManager.IsGenericParameter (parameter_type))
 343                                 return true;
 344
 345                         return member.IsAccessibleAs (parameter_type);
 346                 }
 347
 348                 public override IResolveContext ResolveContext {
 349                         get {
 350                                 return resolve_context;
 351                         }
 352                 }
 353
 354                 // <summary>
 355                 //   Resolve is used in method definitions
 356                 // </summary>
 357                 public virtual Type Resolve (IResolveContext ec)
 358                 {
 359                         // HACK: to resolve attributes correctly
 360                         this.resolve_context = ec;
 361
 362                         if (parameter_type != null)
 363                                 return parameter_type;
 364
 365                         TypeExpr texpr = TypeName.ResolveAsTypeTerminal (ec, false);
 366                         if (texpr == null)
 367                                 return null;
 368
 369                         parameter_type = texpr.Type;
 370
 371                         if ((modFlags & Parameter.Modifier.ISBYREF) != 0 &&
 372                                 TypeManager.IsSpecialType (parameter_type)) {
 373                                 Report.Error (1601, Location, "Method or delegate parameter cannot be of type `{0}'",
 374                                         GetSignatureForError ());
 375                                 return null;
 376                         }
 377
 378 #if GMCS_SOURCE
 379                         if (parameter_type.IsGenericParameter) {
 380                                 AbstractPropertyEventMethod accessor = ec as AbstractPropertyEventMethod;
 381                                 if (accessor == null || !accessor.IsDummy) {
 382                                         if ((parameter_type.GenericParameterAttributes & GenericParameterAttributes.Covariant) != 0) {
 383                                                 Report.Error (-38, Location, "Covariant type parameters cannot be used as method parameters");
 384                                                 return null;
 385                                         } else if ((ModFlags & Modifier.ISBYREF) != 0 &&
 386                                                    (parameter_type.GenericParameterAttributes & GenericParameterAttributes.Contravariant) != 0) {
 387                                                 Report.Error (-37, Location, "Contravariant type parameters cannot be used in output positions");
 388                                                 return null;
 389                                         }
 390                                 }
 391                                 return parameter_type;
 392                         }
 393 #endif
 394
 395                         if ((parameter_type.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute) {
 396                                 Report.Error (721, Location, "`{0}': static types cannot be used as parameters",
 397                                         texpr.GetSignatureForError ());
 398                                 return parameter_type;
 399                         }
 400
 401                         if ((modFlags & Modifier.This) != 0 && parameter_type.IsPointer) {
 402                                 Report.Error (1103, Location, "The type of extension method cannot be `{0}'",
 403                                         TypeManager.CSharpName (parameter_type));
 404                         }
 405
 406                         return parameter_type;
 407                 }
 408
 409                 public void ResolveVariable (int idx)
 410                 {
 411                         this.idx = idx;
 412                 }
 413
 414                 public bool HasExtensionMethodModifier {
 415                         get { return (modFlags & Modifier.This) != 0; }
 416                 }
 417
 418                 public Modifier ModFlags {
 419                         get { return modFlags & ~Modifier.This; }
 420                 }
 421
 422                 public string Name {
 423                         get { return name; }
 424                         set { name = value; }
 425                 }
 426
 427                 ParameterAttributes Attributes {
 428                         get { return ParametersCompiled.GetParameterAttribute (modFlags); }
 429                 }
 430
 431                 public override AttributeTargets AttributeTargets {
 432                         get {
 433                                 return AttributeTargets.Parameter;
 434                         }
 435                 }
 436
 437                 public virtual string GetSignatureForError ()
 438                 {
 439                         string type_name;
 440                         if (parameter_type != null)
 441                                 type_name = TypeManager.CSharpName (parameter_type);
 442                         else
 443                                 type_name = TypeName.GetSignatureForError ();
 444
 445                         string mod = GetModifierSignature (modFlags);
 446                         if (mod.Length > 0)
 447                                 return String.Concat (mod, " ", type_name);
 448
 449                         return type_name;
 450                 }
 451
 452                 public static string GetModifierSignature (Modifier mod)
 453                 {
 454                         switch (mod) {
 455                         case Modifier.OUT:
 456                                 return "out";
 457                         case Modifier.PARAMS:
 458                                 return "params";
 459                         case Modifier.REF:
 460                                 return "ref";
 461                         case Modifier.This:
 462                                 return "this";
 463                         default:
 464                                 return "";
 465                         }
 466                 }
 467
 468                 public void IsClsCompliant ()
 469                 {
 470                         if (AttributeTester.IsClsCompliant (parameter_type))
 471                                 return;
 472
 473                         Report.Warning (3001, 1, Location, "Argument type `{0}' is not CLS-compliant", GetSignatureForError ());
 474                 }
 475
 476                 public virtual void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index)
 477                 {
 478                         if (mb == null)
 479                                 builder = cb.DefineParameter (index, Attributes, Name);
 480                         else
 481                                 builder = mb.DefineParameter (index, Attributes, Name);
 482
 483                         if (OptAttributes != null)
 484                                 OptAttributes.Emit ();
 485                 }
 486
 487                 public override string[] ValidAttributeTargets {
 488                         get {
 489                                 return attribute_targets;
 490                         }
 491                 }
 492
 493                 public Parameter Clone ()
 494                 {
 495                         Parameter p = (Parameter) MemberwiseClone ();
 496                         if (attributes != null) {
 497                                 p.attributes = attributes.Clone ();
 498                                 p.attributes.AttachTo (p);
 499                         }
 500
 501                         return p;
 502                 }
 503
 504                 public ExpressionStatement CreateExpressionTreeVariable (EmitContext ec)
 505                 {
 506                         if ((modFlags & Modifier.ISBYREF) != 0)
 507                                 Report.Error (1951, Location, "An expression tree parameter cannot use `ref' or `out' modifier");
 508
 509                         LocalInfo variable = ec.CurrentBlock.AddTemporaryVariable (
 510                                 ResolveParameterExpressionType (ec, Location), Location);
 511                         variable.Resolve (ec);
 512
 513                         expr_tree_variable = new LocalVariableReference (
 514                                 ec.CurrentBlock, variable.Name, Location, variable, false);
 515
 516                         ArrayList arguments = new ArrayList (2);
 517                         arguments.Add (new Argument (new TypeOf (
 518                                 new TypeExpression (parameter_type, Location), Location)));
 519                         arguments.Add (new Argument (new StringConstant (Name, Location)));
 520                         return new SimpleAssign (ExpressionTreeVariableReference (),
 521                                 Expression.CreateExpressionFactoryCall ("Parameter", null, arguments, Location));
 522                 }
 523
 524                 public void Emit (EmitContext ec)
 525                 {
 526                         int arg_idx = idx;
 527                         if (!ec.IsStatic)
 528                                 arg_idx++;
 529
 530                         ParameterReference.EmitLdArg (ec.ig, arg_idx);
 531                 }
 532
 533                 public void EmitAssign (EmitContext ec)
 534                 {
 535                         int arg_idx = idx;
 536                         if (!ec.IsStatic)
 537                                 arg_idx++;
 538
 539                         if (arg_idx <= 255)
 540                                 ec.ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
 541                         else
 542                                 ec.ig.Emit (OpCodes.Starg, arg_idx);
 543                 }
 544
 545                 public void EmitAddressOf (EmitContext ec)
 546                 {
 547                         int arg_idx = idx;
 548
 549                         if (!ec.IsStatic)
 550                                 arg_idx++;
 551
 552                         bool is_ref = (ModFlags & Modifier.ISBYREF) != 0;
 553                         if (is_ref) {
 554                                 ParameterReference.EmitLdArg (ec.ig, arg_idx);
 555                         } else {
 556                                 if (arg_idx <= 255)
 557                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
 558                                 else
 559                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
 560                         }
 561                 }
 562
 563                 public Expression ExpressionTreeVariableReference ()
 564                 {
 565                         return expr_tree_variable;
 566                 }
 567
 568                 //
 569                 // System.Linq.Expressions.ParameterExpression type
 570                 //
 571                 public static TypeExpr ResolveParameterExpressionType (EmitContext ec, Location location)
 572                 {
 573                         if (parameter_expr_tree_type != null)
 574                                 return parameter_expr_tree_type;
 575
 576                         Type p_type = TypeManager.parameter_expression_type;
 577                         if (p_type == null) {
 578                                 p_type = TypeManager.CoreLookupType ("System.Linq.Expressions", "ParameterExpression", Kind.Class, true);
 579                                 TypeManager.parameter_expression_type = p_type;
 580                         }
 581
 582                         parameter_expr_tree_type = new TypeExpression (p_type, location).
 583                                 ResolveAsTypeTerminal (ec, false);
 584
 585                         return parameter_expr_tree_type;
 586                 }
 587         }
 588
 589         //
 590         // Imported or resolved parameter information
 591         //
 592         public class ParameterData : IParameterData
 593         {
 594                 readonly string name;
 595                 readonly Parameter.Modifier modifiers;
 596
 597                 public ParameterData (string name, Parameter.Modifier modifiers)
 598                 {
 599                         this.name = name;
 600                         this.modifiers = modifiers;
 601                 }
 602
 603                 #region IParameterData Members
 604
 605                 public bool HasExtensionMethodModifier {
 606                         get { return (modifiers & Parameter.Modifier.This) != 0; }
 607                 }
 608
 609                 public Parameter.Modifier ModFlags {
 610                         get { return modifiers & ~Parameter.Modifier.This; }
 611                 }
 612
 613                 public string Name {
 614                         get { return name; }
 615                 }
 616
 617                 #endregion
 618         }
 619
 620         public abstract class AParametersCollection
 621         {
 622                 protected bool has_arglist;
 623                 protected bool has_params;
 624
 625                 // Null object pattern
 626                 protected IParameterData [] parameters;
 627                 protected Type [] types;
 628
 629                 public int Count {
 630                         get { return parameters.Length; }
 631                 }
 632
 633                 public Type ExtensionMethodType {
 634                         get {
 635                                 if (Count == 0)
 636                                         return null;
 637
 638                                 return FixedParameters [0].HasExtensionMethodModifier ?
 639                                         types [0] : null;
 640                         }
 641                 }
 642
 643                 public IParameterData [] FixedParameters {
 644                         get {
 645                                 return parameters;
 646                         }
 647                 }
 648
 649                 public static ParameterAttributes GetParameterAttribute (Parameter.Modifier modFlags)
 650                 {
 651                         return (modFlags & Parameter.Modifier.OUT) == Parameter.Modifier.OUT ?
 652                                 ParameterAttributes.Out : ParameterAttributes.None;
 653                 }
 654
 655                 public Type [] GetEmitTypes ()
 656                 {
 657                         Type [] types = null;
 658                         if (has_arglist) {
 659                                 if (Count == 1)
 660                                         return Type.EmptyTypes;
 661
 662                                 types = new Type [Count - 1];
 663                                 Array.Copy (Types, types, types.Length);
 664                         }
 665
 666                         for (int i = 0; i < Count; ++i) {
 667                                 if ((FixedParameters [i].ModFlags & Parameter.Modifier.ISBYREF) == 0)
 668                                         continue;
 669
 670                                 if (types == null)
 671                                         types = (Type []) Types.Clone ();
 672
 673                                 types [i] = TypeManager.GetReferenceType (types [i]);
 674                         }
 675
 676                         if (types == null)
 677                                 types = Types;
 678
 679                         return types;
 680                 }
 681
 682                 public string GetSignatureForError ()
 683                 {
 684                         StringBuilder sb = new StringBuilder ("(");
 685                         for (int i = 0; i < Count; ++i) {
 686                                 if (i != 0)
 687                                         sb.Append (", ");
 688                                 sb.Append (ParameterDesc (i));
 689                         }
 690                         sb.Append (')');
 691                         return sb.ToString ();
 692                 }
 693
 694                 public bool HasArglist {
 695                         get { return has_arglist; }
 696                 }
 697
 698                 public bool HasExtensionMethodType {
 699                         get {
 700                                 if (Count == 0)
 701                                         return false;
 702
 703                                 return FixedParameters [0].HasExtensionMethodModifier;
 704                         }
 705                 }
 706
 707                 public bool HasParams {
 708                         get { return has_params; }
 709                 }
 710
 711                 public bool IsEmpty {
 712                         get { return parameters.Length == 0; }
 713                 }
 714
 715                 public string ParameterDesc (int pos)
 716                 {
 717                         if (types == null || types [pos] == null)
 718                                 return ((Parameter)FixedParameters [pos]).GetSignatureForError ();
 719
 720                         string type = TypeManager.CSharpName (types [pos]);
 721                         if (FixedParameters [pos].HasExtensionMethodModifier)
 722                                 return "this " + type;
 723
 724                         Parameter.Modifier mod = FixedParameters [pos].ModFlags & ~Parameter.Modifier.ARGLIST;
 725                         if (mod == 0)
 726                                 return type;
 727
 728                         return Parameter.GetModifierSignature (mod) + " " + type;
 729                 }
 730
 731                 public Type[] Types {
 732                         get { return types; }
 733                         set { types = value; }
 734                 }
 735
 736 #if MS_COMPATIBLE
 737                 public AParametersCollection InflateTypes (Type[] genArguments, Type[] argTypes)
 738                 {
 739                         AParametersCollection p = (AParametersCollection) MemberwiseClone (); // Clone ();
 740
 741                         for (int i = 0; i < Count; ++i) {
 742                                 if (types[i].IsGenericType) {
 743                                         Type[] gen_arguments_open = new Type[types[i].GetGenericTypeDefinition ().GetGenericArguments ().Length];
 744                                         Type[] gen_arguments = types[i].GetGenericArguments ();
 745                                         for (int ii = 0; ii < gen_arguments_open.Length; ++ii) {
 746                                                 if (gen_arguments[ii].IsGenericParameter) {
 747                                                         Type t = argTypes[gen_arguments[ii].GenericParameterPosition];
 748                                                         gen_arguments_open[ii] = t;
 749                                                 } else
 750                                                         gen_arguments_open[ii] = gen_arguments[ii];
 751                                         }
 752
 753                                         p.types[i] = types[i].GetGenericTypeDefinition ().MakeGenericType (gen_arguments_open);
 754                                         continue;
 755                                 }
 756
 757                                 if (types[i].IsGenericParameter) {
 758                                         Type gen_argument = argTypes[types[i].GenericParameterPosition];
 759                                         p.types[i] = gen_argument;
 760                                         continue;
 761                                 }
 762                         }
 763
 764                         return p;
 765                 }
 766 #endif
 767         }
 768
 769         //
 770         // A collection of imported or resolved parameters
 771         //
 772         public class ParametersImported : AParametersCollection
 773         {
 774                 ParametersImported (AParametersCollection param, Type[] types)
 775                 {
 776                         this.parameters = param.FixedParameters;
 777                         this.types = types;
 778                         has_arglist = param.HasArglist;
 779                         has_params = param.HasParams;
 780                 }
 781
 782                 ParametersImported (IParameterData [] parameters, Type [] types, MethodBase method, bool hasParams)
 783                 {
 784                         this.parameters = parameters;
 785                         this.types = types;
 786                         has_arglist = (method.CallingConvention & CallingConventions.VarArgs) != 0;
 787                         if (has_arglist) {
 788                                 this.parameters = new IParameterData [parameters.Length + 1];
 789                                 parameters.CopyTo (this.parameters, 0);
 790                                 this.parameters [parameters.Length] = new ArglistParameter (Location.Null);
 791                                 this.types = new Type [types.Length + 1];
 792                                 types.CopyTo (this.types, 0);
 793                                 this.types [types.Length] = TypeManager.arg_iterator_type;
 794                         }
 795                         has_params = hasParams;
 796                 }
 797
 798                 public ParametersImported (IParameterData [] param, Type[] types)
 799                 {
 800                         this.parameters = param;
 801                         this.types = types;
 802                 }
 803
 804                 public static AParametersCollection Create (MethodBase method)
 805                 {
 806                         return Create (method.GetParameters (), method);
 807                 }
 808
 809                 //
 810                 // Generic method parameters importer, param is shared between all instances
 811                 //
 812                 public static AParametersCollection Create (AParametersCollection param, MethodBase method)
 813                 {
 814                         if (param.IsEmpty)
 815                                 return param;
 816
 817                         ParameterInfo [] pi = method.GetParameters ();
 818                         Type [] types = new Type [pi.Length];
 819                         for (int i = 0; i < types.Length; i++) {
 820                                 Type t = pi [i].ParameterType;
 821                                 if (t.IsByRef)
 822                                         t = TypeManager.GetElementType (t);
 823
 824                                 types [i] = TypeManager.TypeToCoreType (t);
 825                         }
 826
 827                         return new ParametersImported (param, types);
 828                 }
 829
 830                 //
 831                 // Imports SRE parameters
 832                 //
 833                 public static AParametersCollection Create (ParameterInfo [] pi, MethodBase method)
 834                 {
 835                         if (pi.Length == 0) {
 836                                 if (method != null && (method.CallingConvention & CallingConventions.VarArgs) != 0)
 837                                         return new ParametersImported (new IParameterData [0], Type.EmptyTypes, method, false);
 838
 839                                 return ParametersCompiled.EmptyReadOnlyParameters;
 840                         }
 841
 842                         Type [] types = new Type [pi.Length];
 843                         IParameterData [] par = new IParameterData [pi.Length];
 844                         bool is_params = false;
 845                         for (int i = 0; i < types.Length; i++) {
 846                                 types [i] = TypeManager.TypeToCoreType (pi [i].ParameterType);
 847
 848                                 ParameterInfo p = pi [i];
 849                                 Parameter.Modifier mod = 0;
 850                                 if (types [i].IsByRef) {
 851                                         if ((p.Attributes & (ParameterAttributes.Out | ParameterAttributes.In)) == ParameterAttributes.Out)
 852                                                 mod = Parameter.Modifier.OUT;
 853                                         else
 854                                                 mod = Parameter.Modifier.REF;
 855
 856                                         //
 857                                         // Strip reference wrapping
 858                                         //
 859                                         types [i] = TypeManager.GetElementType (types [i]);
 860                                 } else if (i == 0 && TypeManager.extension_attribute_type != null && method != null && method.IsStatic &&
 861                                 (method.DeclaringType.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 862                                 method.IsDefined (TypeManager.extension_attribute_type, false)) {
 863                                         mod = Parameter.Modifier.This;
 864                                 } else if (i >= pi.Length - 2 && types [i].IsArray) {
 865                                         if (p.IsDefined (TypeManager.param_array_type, false)) {
 866                                                 mod = Parameter.Modifier.PARAMS;
 867                                                 is_params = true;
 868                                         }
 869                                 }
 870
 871                                 par [i] = new ParameterData (p.Name, mod);
 872                         }
 873
 874                         return method != null ?
 875                                 new ParametersImported (par, types, method, is_params) :
 876                                 new ParametersImported (par, types);
 877                 }
 878         }
 879
 880         /// <summary>
 881         ///   Represents the methods parameters
 882         /// </summary>
 883         public class ParametersCompiled : AParametersCollection
 884         {
 885                 public static readonly ParametersCompiled EmptyReadOnlyParameters = new ParametersCompiled ();
 886
 887                 // Used by C# 2.0 delegates
 888                 public static readonly ParametersCompiled Undefined = new ParametersCompiled ();
 889
 890                 private ParametersCompiled ()
 891                 {
 892                         parameters = new Parameter [0];
 893                         types = Type.EmptyTypes;
 894                 }
 895
 896                 private ParametersCompiled (Parameter [] parameters, Type [] types)
 897                 {
 898                         this.parameters = parameters;
 899                     this.types = types;
 900                 }
 901
 902                 public ParametersCompiled (params Parameter[] parameters)
 903                 {
 904                         if (parameters == null)
 905                                 throw new ArgumentException ("Use EmptyReadOnlyParameters");
 906
 907                         this.parameters = parameters;
 908                         int count = parameters.Length;
 909
 910                         if (count == 0)
 911                                 return;
 912
 913                         if (count == 1) {
 914                                 has_params = (parameters [0].ModFlags & Parameter.Modifier.PARAMS) != 0;
 915                                 return;
 916                         }
 917
 918                         for (int i = 0; i < count; i++){
 919                                 string base_name = parameters [i].Name;
 920                                 has_params |= (parameters [i].ModFlags & Parameter.Modifier.PARAMS) != 0;
 921
 922                                 for (int j = i + 1; j < count; j++){
 923                                         if (base_name != parameters [j].Name)
 924                                                 continue;
 925
 926                                         ErrorDuplicateName (parameters [i]);
 927                                         i = j;
 928                                 }
 929                         }
 930                 }
 931
 932                 public ParametersCompiled (Parameter [] parameters, bool has_arglist) :
 933                         this (parameters)
 934                 {
 935                         this.has_arglist = has_arglist;
 936                 }
 937
 938                 public static ParametersCompiled CreateFullyResolved (Parameter p, Type type)
 939                 {
 940                         return new ParametersCompiled (new Parameter [] { p }, new Type [] { type });
 941                 }
 942
 943                 public static ParametersCompiled CreateFullyResolved (Parameter[] parameters, Type[] types)
 944                 {
 945                         return new ParametersCompiled (parameters, types);
 946                 }
 947
 948                 public static ParametersCompiled MergeGenerated (ParametersCompiled userParams, bool checkConflicts, Parameter compilerParams, Type compilerTypes)
 949                 {
 950                         return MergeGenerated (userParams, checkConflicts,
 951                                 new Parameter [] { compilerParams },
 952                                 new Type [] { compilerTypes });
 953                 }
 954
 955                 //
 956                 // Use this method when you merge compiler generated parameters with user parameters
 957                 //
 958                 public static ParametersCompiled MergeGenerated (ParametersCompiled userParams, bool checkConflicts, Parameter[] compilerParams, Type[] compilerTypes)
 959                 {
 960                         Parameter[] all_params = new Parameter [userParams.Count + compilerParams.Length];
 961                         userParams.FixedParameters.CopyTo(all_params, 0);
 962
 963                         Type [] all_types;
 964                         if (userParams.types != null) {
 965                                 all_types = new Type [all_params.Length];
 966                                 userParams.Types.CopyTo (all_types, 0);
 967                         } else {
 968                                 all_types = null;
 969                         }
 970
 971                         int last_filled = userParams.Count;
 972                         int index = 0;
 973                         foreach (Parameter p in compilerParams) {
 974                                 for (int i = 0; i < last_filled; ++i) {
 975                                         while (p.Name == all_params [i].Name) {
 976                                                 if (checkConflicts && i < userParams.Count) {
 977                                                         Report.Error (316, userParams [i].Location,
 978                                                                 "The parameter name `{0}' conflicts with a compiler generated name", p.Name);
 979                                                 }
 980                                                 p.Name = '_' + p.Name;
 981                                         }
 982                                 }
 983                                 all_params [last_filled] = p;
 984                                 if (all_types != null)
 985                                         all_types [last_filled] = compilerTypes [index++];
 986                                 ++last_filled;
 987                         }
 988
 989                         ParametersCompiled parameters = new ParametersCompiled (all_params, all_types);
 990                         parameters.has_params = userParams.has_params;
 991                         return parameters;
 992                 }
 993
 994                 protected virtual void ErrorDuplicateName (Parameter p)
 995                 {
 996                         Report.Error (100, p.Location, "The parameter name `{0}' is a duplicate", p.Name);
 997                 }
 998
 999                 /// <summary>
1000                 ///    Returns the parameter information based on the name
1001                 /// </summary>
1002                 public int GetParameterIndexByName (string name)
1003                 {
1004                         for (int idx = 0; idx < Count; ++idx) {
1005                                 if (parameters [idx].Name == name)
1006                                         return idx;
1007                         }
1008
1009                         return -1;
1010                 }
1011
1012                 public bool Resolve (IResolveContext ec)
1013                 {
1014                         if (types != null)
1015                                 return true;
1016
1017                         types = new Type [Count];
1018
1019                         bool ok = true;
1020                         Parameter p;
1021                         for (int i = 0; i < FixedParameters.Length; ++i) {
1022                                 p = this [i];
1023                                 Type t = p.Resolve (ec);
1024                                 if (t == null) {
1025                                         ok = false;
1026                                         continue;
1027                                 }
1028
1029                                 types [i] = t;
1030                         }
1031
1032                         return ok;
1033                 }
1034
1035                 public void ResolveVariable ()
1036                 {
1037                         for (int i = 0; i < FixedParameters.Length; ++i) {
1038                                 this [i].ResolveVariable (i);
1039                         }
1040                 }
1041
1042                 public CallingConventions CallingConvention
1043                 {
1044                         get {
1045                                 if (HasArglist)
1046                                         return CallingConventions.VarArgs;
1047                                 else
1048                                         return CallingConventions.Standard;
1049                         }
1050                 }
1051
1052                 // Define each type attribute (in/out/ref) and
1053                 // the argument names.
1054                 public void ApplyAttributes (MethodBase builder)
1055                 {
1056                         if (Count == 0)
1057                                 return;
1058
1059                         MethodBuilder mb = builder as MethodBuilder;
1060                         ConstructorBuilder cb = builder as ConstructorBuilder;
1061
1062                         for (int i = 0; i < Count; i++) {
1063                                 this [i].ApplyAttributes (mb, cb, i + 1);
1064                         }
1065                 }
1066
1067                 public void VerifyClsCompliance ()
1068                 {
1069                         foreach (Parameter p in FixedParameters)
1070                                 p.IsClsCompliant ();
1071                 }
1072
1073                 public Parameter this [int pos] {
1074                         get { return (Parameter) parameters [pos]; }
1075                 }
1076
1077                 public Expression CreateExpressionTree (EmitContext ec, Location loc)
1078                 {
1079                         ArrayList initializers = new ArrayList (Count);
1080                         foreach (Parameter p in FixedParameters) {
1081                                 //
1082                                 // Each parameter expression is stored to local variable
1083                                 // to save some memory when referenced later.
1084                                 //
1085                                 StatementExpression se = new StatementExpression (p.CreateExpressionTreeVariable (ec));
1086                                 if (se.Resolve (ec))
1087                                         ec.CurrentBlock.AddScopeStatement (se);
1088
1089                                 initializers.Add (p.ExpressionTreeVariableReference ());
1090                         }
1091
1092                         return new ArrayCreation (
1093                                 Parameter.ResolveParameterExpressionType (ec, loc),
1094                                 "[]", initializers, loc);
1095                 }
1096
1097                 public ParametersCompiled Clone ()
1098                 {
1099                         ParametersCompiled p = (ParametersCompiled) MemberwiseClone ();
1100
1101                         p.parameters = new IParameterData [parameters.Length];
1102                         for (int i = 0; i < Count; ++i)
1103                                 p.parameters [i] = this [i].Clone ();
1104
1105                         return p;
1106                 }
1107         }
1108 }