mcs/mcs/parameter.cs

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