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