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 // Copyright 2011 Xamarin Inc
  12 //
  13 //
  14 using System;
  15 using System.Text;
  16
  17 #if STATIC
  18 using MetaType = IKVM.Reflection.Type;
  19 using IKVM.Reflection;
  20 using IKVM.Reflection.Emit;
  21 #else
  22 using MetaType = System.Type;
  23 using System.Reflection;
  24 using System.Reflection.Emit;
  25 #endif
  26
  27 namespace Mono.CSharp {
  28
  29         /// <summary>
  30         ///   Abstract Base class for parameters of a method.
  31         /// </summary>
  32         public abstract class ParameterBase : Attributable
  33         {
  34                 protected ParameterBuilder builder;
  35
  36                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
  37                 {
  38 #if false
  39                         if (a.Type == pa.MarshalAs) {
  40                                 UnmanagedMarshal marshal = a.GetMarshal (this);
  41                                 if (marshal != null) {
  42                                         builder.SetMarshal (marshal);
  43                                 }
  44                                 return;
  45                         }
  46 #endif
  47                         if (a.HasSecurityAttribute) {
  48                                 a.Error_InvalidSecurityParent ();
  49                                 return;
  50                         }
  51
  52                         if (a.Type == pa.Dynamic) {
  53                                 a.Error_MisusedDynamicAttribute ();
  54                                 return;
  55                         }
  56
  57                         builder.SetCustomAttribute ((ConstructorInfo) ctor.GetMetaInfo (), cdata);
  58                 }
  59
  60                 public ParameterBuilder Builder {
  61                         get {
  62                                 return builder;
  63                         }
  64                 }
  65
  66                 public override bool IsClsComplianceRequired()
  67                 {
  68                         return false;
  69                 }
  70         }
  71
  72         /// <summary>
  73         /// Class for applying custom attributes on the return type
  74         /// </summary>
  75         public class ReturnParameter : ParameterBase
  76         {
  77                 MemberCore method;
  78
  79                 // TODO: merge method and mb
  80                 public ReturnParameter (MemberCore method, MethodBuilder mb, Location location)
  81                 {
  82                         this.method = method;
  83                         try {
  84                                 builder = mb.DefineParameter (0, ParameterAttributes.None, "");
  85                         }
  86                         catch (ArgumentOutOfRangeException) {
  87                                 method.Compiler.Report.RuntimeMissingSupport (location, "custom attributes on the return type");
  88                         }
  89                 }
  90
  91                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
  92                 {
  93                         if (a.Type == pa.CLSCompliant) {
  94                                 method.Compiler.Report.Warning (3023, 1, a.Location,
  95                                         "CLSCompliant attribute has no meaning when applied to return types. Try putting it on the method instead");
  96                         }
  97
  98                         // This occurs after Warning -28
  99                         if (builder == null)
 100                                 return;
 101
 102                         base.ApplyAttributeBuilder (a, ctor, cdata, pa);
 103                 }
 104
 105                 public override AttributeTargets AttributeTargets {
 106                         get {
 107                                 return AttributeTargets.ReturnValue;
 108                         }
 109                 }
 110
 111                 /// <summary>
 112                 /// Is never called
 113                 /// </summary>
 114                 public override string[] ValidAttributeTargets {
 115                         get {
 116                                 return null;
 117                         }
 118                 }
 119         }
 120
 121         public class ImplicitLambdaParameter : Parameter
 122         {
 123                 public ImplicitLambdaParameter (string name, Location loc)
 124                         : base (null, name, Modifier.NONE, null, loc)
 125                 {
 126                 }
 127
 128                 public override TypeSpec Resolve (IMemberContext ec, int index)
 129                 {
 130                         if (parameter_type == null)
 131                                 throw new InternalErrorException ("A type of implicit lambda parameter `{0}' is not set",
 132                                         Name);
 133
 134                         base.idx = index;
 135                         return parameter_type;
 136                 }
 137
 138                 public void SetParameterType (TypeSpec type)
 139                 {
 140                         parameter_type = type;
 141                 }
 142         }
 143
 144         public class ParamsParameter : Parameter {
 145                 public ParamsParameter (FullNamedExpression type, string name, Attributes attrs, Location loc):
 146                         base (type, name, Parameter.Modifier.PARAMS, attrs, loc)
 147                 {
 148                 }
 149
 150                 public override TypeSpec Resolve (IMemberContext ec, int index)
 151                 {
 152                         if (base.Resolve (ec, index) == null)
 153                                 return null;
 154
 155                         var ac = parameter_type as ArrayContainer;
 156                         if (ac == null || ac.Rank != 1) {
 157                                 ec.Module.Compiler.Report.Error (225, Location, "The params parameter must be a single dimensional array");
 158                                 return null;
 159                         }
 160
 161                         return parameter_type;
 162                 }
 163
 164                 public override void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index, PredefinedAttributes pa)
 165                 {
 166                         base.ApplyAttributes (mb, cb, index, pa);
 167                         pa.ParamArray.EmitAttribute (builder);
 168                 }
 169         }
 170
 171         public class ArglistParameter : Parameter {
 172                 // Doesn't have proper type because it's never chosen for better conversion
 173                 public ArglistParameter (Location loc) :
 174                         base (null, String.Empty, Parameter.Modifier.NONE, null, loc)
 175                 {
 176                         parameter_type = InternalType.Arglist;
 177                 }
 178
 179                 public override void  ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index, PredefinedAttributes pa)
 180                 {
 181                         // Nothing to do
 182                 }
 183
 184                 public override bool CheckAccessibility (InterfaceMemberBase member)
 185                 {
 186                         return true;
 187                 }
 188
 189                 public override TypeSpec Resolve (IMemberContext ec, int index)
 190                 {
 191                         return parameter_type;
 192                 }
 193         }
 194
 195         public interface IParameterData
 196         {
 197                 Expression DefaultValue { get; }
 198                 bool HasExtensionMethodModifier { get; }
 199                 bool HasDefaultValue { get; }
 200                 Parameter.Modifier ModFlags { get; }
 201                 string Name { get; }
 202         }
 203
 204         //
 205         // Parameter information created by parser
 206         //
 207         public class Parameter : ParameterBase, IParameterData, ILocalVariable // TODO: INamedBlockVariable
 208         {
 209                 [Flags]
 210                 public enum Modifier : byte {
 211                         NONE    = 0,
 212                         PARAMS  = 1 << 0,
 213                         REF = 1 << 1,
 214                         OUT = 1 << 2,
 215                         This = 1 << 3,
 216                         CallerMemberName = 1 << 4,
 217                         CallerLineNumber = 1 << 5,
 218                         CallerFilePath = 1 << 6,
 219
 220                         RefOutMask = REF | OUT,
 221                         ModifierMask = PARAMS | REF | OUT | This,
 222                         CallerMask = CallerMemberName | CallerLineNumber | CallerFilePath
 223                 }
 224
 225                 static readonly string[] attribute_targets = new [] { "param" };
 226
 227                 FullNamedExpression texpr;
 228                 Modifier modFlags;
 229                 string name;
 230                 Expression default_expr;
 231                 protected TypeSpec parameter_type;
 232                 readonly Location loc;
 233                 protected int idx;
 234                 public bool HasAddressTaken;
 235
 236                 TemporaryVariableReference expr_tree_variable;
 237
 238                 HoistedParameter hoisted_variant;
 239
 240                 public Parameter (FullNamedExpression type, string name, Modifier mod, Attributes attrs, Location loc)
 241                 {
 242                         this.name = name;
 243                         modFlags = mod;
 244                         this.loc = loc;
 245                         texpr = type;
 246
 247                         // Only assign, attributes will be attached during resolve
 248                         base.attributes = attrs;
 249                 }
 250
 251                 #region Properties
 252
 253                 public Expression DefaultExpression {
 254                         get {
 255                                 return default_expr;
 256                         }
 257                 }
 258
 259                 public DefaultParameterValueExpression DefaultValue {
 260                         get {
 261                                 return default_expr as DefaultParameterValueExpression;
 262                         }
 263                         set {
 264                                 default_expr = value;
 265                         }
 266                 }
 267
 268                 Expression IParameterData.DefaultValue {
 269                         get {
 270                                 var expr = default_expr as DefaultParameterValueExpression;
 271                                 return expr == null ? default_expr : expr.Child;
 272                         }
 273                 }
 274
 275                 bool HasOptionalExpression {
 276                         get {
 277                                 return default_expr is DefaultParameterValueExpression;
 278                         }
 279                 }
 280
 281                 public Location Location {
 282                         get {
 283                                 return loc;
 284                         }
 285                 }
 286
 287                 public Modifier ParameterModifier {
 288                         get {
 289                                 return modFlags;
 290                         }
 291                 }
 292
 293                 public TypeSpec Type {
 294                         get {
 295                                 return parameter_type;
 296                         }
 297                         set {
 298                                 parameter_type = value;
 299                         }
 300                 }
 301
 302                 public FullNamedExpression TypeExpression  {
 303                         get {
 304                                 return texpr;
 305                         }
 306                 }
 307
 308                 public override string[] ValidAttributeTargets {
 309                         get {
 310                                 return attribute_targets;
 311                         }
 312                 }
 313
 314                 #endregion
 315
 316                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
 317                 {
 318                         if (a.Type == pa.In && ModFlags == Modifier.OUT) {
 319                                 a.Report.Error (36, a.Location, "An out parameter cannot have the `In' attribute");
 320                                 return;
 321                         }
 322
 323                         if (a.Type == pa.ParamArray) {
 324                                 a.Report.Error (674, a.Location, "Do not use `System.ParamArrayAttribute'. Use the `params' keyword instead");
 325                                 return;
 326                         }
 327
 328                         if (a.Type == pa.Out && (ModFlags & Modifier.REF) != 0 &&
 329                             !OptAttributes.Contains (pa.In)) {
 330                                 a.Report.Error (662, a.Location,
 331                                         "Cannot specify only `Out' attribute on a ref parameter. Use both `In' and `Out' attributes or neither");
 332                                 return;
 333                         }
 334
 335                         if (a.Type == pa.CLSCompliant) {
 336                                 a.Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
 337                         } else if (a.Type == pa.DefaultParameterValue || a.Type == pa.OptionalParameter) {
 338                                 if (HasOptionalExpression) {
 339                                         a.Report.Error (1745, a.Location,
 340                                                 "Cannot specify `{0}' attribute on optional parameter `{1}'",
 341                                                 a.Type.GetSignatureForError ().Replace ("Attribute", ""), Name);
 342                                 }
 343
 344                                 if (a.Type == pa.DefaultParameterValue)
 345                                         return;
 346                         } else if (a.Type == pa.CallerMemberNameAttribute) {
 347                                 if ((modFlags & Modifier.CallerMemberName) == 0) {
 348                                         a.Report.Error (4022, a.Location,
 349                                                 "The CallerMemberName attribute can only be applied to parameters with default value");
 350                                 }
 351                         } else if (a.Type == pa.CallerLineNumberAttribute) {
 352                                 if ((modFlags & Modifier.CallerLineNumber) == 0) {
 353                                         a.Report.Error (4020, a.Location,
 354                                                 "The CallerLineNumber attribute can only be applied to parameters with default value");
 355                                 }
 356                         } else if (a.Type == pa.CallerFilePathAttribute) {
 357                                 if ((modFlags & Modifier.CallerFilePath) == 0) {
 358                                         a.Report.Error (4021, a.Location,
 359                                                 "The CallerFilePath attribute can only be applied to parameters with default value");
 360                                 }
 361                         }
 362
 363                         base.ApplyAttributeBuilder (a, ctor, cdata, pa);
 364                 }
 365
 366                 public virtual bool CheckAccessibility (InterfaceMemberBase member)
 367                 {
 368                         if (parameter_type == null)
 369                                 return true;
 370
 371                         return member.IsAccessibleAs (parameter_type);
 372                 }
 373
 374                 bool IsValidCallerContext (MemberCore memberContext)
 375                 {
 376                         var m = memberContext as Method;
 377                         if (m != null)
 378                                 return !m.IsPartialImplementation;
 379
 380                         return true;
 381                 }
 382
 383                 // <summary>
 384                 //   Resolve is used in method definitions
 385                 // </summary>
 386                 public virtual TypeSpec Resolve (IMemberContext rc, int index)
 387                 {
 388                         if (parameter_type != null)
 389                                 return parameter_type;
 390
 391                         if (attributes != null)
 392                                 attributes.AttachTo (this, rc);
 393
 394                         parameter_type = texpr.ResolveAsType (rc);
 395                         if (parameter_type == null)
 396                                 return null;
 397
 398                         this.idx = index;
 399
 400                         if ((modFlags & Parameter.Modifier.RefOutMask) != 0 && parameter_type.IsSpecialRuntimeType) {
 401                                 rc.Module.Compiler.Report.Error (1601, Location, "Method or delegate parameter cannot be of type `{0}'",
 402                                         GetSignatureForError ());
 403                                 return null;
 404                         }
 405
 406                         VarianceDecl.CheckTypeVariance (parameter_type,
 407                                 (modFlags & Parameter.Modifier.RefOutMask) != 0 ? Variance.None : Variance.Contravariant,
 408                                 rc);
 409
 410                         if (parameter_type.IsStatic) {
 411                                 rc.Module.Compiler.Report.Error (721, Location, "`{0}': static types cannot be used as parameters",
 412                                         texpr.GetSignatureForError ());
 413                                 return parameter_type;
 414                         }
 415
 416                         if ((modFlags & Modifier.This) != 0 && (parameter_type.IsPointer || parameter_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)) {
 417                                 rc.Module.Compiler.Report.Error (1103, Location, "The extension method cannot be of type `{0}'",
 418                                         parameter_type.GetSignatureForError ());
 419                         }
 420
 421                         return parameter_type;
 422                 }
 423
 424                 void ResolveCallerAttributes (ResolveContext rc)
 425                 {
 426                         var pa = rc.Module.PredefinedAttributes;
 427                         TypeSpec caller_type;
 428                         Attribute callerMemberName = null, callerFilePath = null;
 429
 430                         foreach (var attr in attributes.Attrs) {
 431                                 var atype = attr.ResolveTypeForComparison ();
 432                                 if (atype == null)
 433                                         continue;
 434
 435                                 if (atype == pa.CallerMemberNameAttribute) {
 436                                         caller_type = rc.BuiltinTypes.String;
 437                                         if (caller_type != parameter_type && !Convert.ImplicitReferenceConversionExists (caller_type, parameter_type)) {
 438                                                 rc.Report.Error (4019, attr.Location,
 439                                                         "The CallerMemberName attribute cannot be applied because there is no standard conversion from `{0}' to `{1}'",
 440                                                         caller_type.GetSignatureForError (), parameter_type.GetSignatureForError ());
 441                                         }
 442
 443                                         if (!IsValidCallerContext (rc.CurrentMemberDefinition)) {
 444                                                 rc.Report.Warning (4026, 1, attr.Location,
 445                                                         "The CallerMemberName applied to parameter `{0}' will have no effect because it applies to a member that is used in context that do not allow optional arguments",
 446                                                         name);
 447                                         }
 448
 449                                         modFlags |= Modifier.CallerMemberName;
 450                                         callerMemberName = attr;
 451                                         continue;
 452                                 }
 453
 454                                 if (atype == pa.CallerLineNumberAttribute) {
 455                                         caller_type = rc.BuiltinTypes.Int;
 456                                         if (caller_type != parameter_type && !Convert.ImplicitStandardConversionExists (new IntConstant (caller_type, int.MaxValue, Location.Null), parameter_type)) {
 457                                                 rc.Report.Error (4017, attr.Location,
 458                                                         "The CallerLineNumberAttribute attribute cannot be applied because there is no standard conversion from `{0}' to `{1}'",
 459                                                         caller_type.GetSignatureForError (), parameter_type.GetSignatureForError ());
 460                                         }
 461
 462                                         if (!IsValidCallerContext (rc.CurrentMemberDefinition)) {
 463                                                 rc.Report.Warning (4024, 1, attr.Location,
 464                                                         "The CallerLineNumberAttribute applied to parameter `{0}' will have no effect because it applies to a member that is used in context that do not allow optional arguments",
 465                                                         name);
 466                                         }
 467
 468                                         modFlags |= Modifier.CallerLineNumber;
 469                                         continue;
 470                                 }
 471
 472                                 if (atype == pa.CallerFilePathAttribute) {
 473                                         caller_type = rc.BuiltinTypes.String;
 474                                         if (caller_type != parameter_type && !Convert.ImplicitReferenceConversionExists (caller_type, parameter_type)) {
 475                                                 rc.Report.Error (4018, attr.Location,
 476                                                         "The CallerFilePath attribute cannot be applied because there is no standard conversion from `{0}' to `{1}'",
 477                                                         caller_type.GetSignatureForError (), parameter_type.GetSignatureForError ());
 478                                         }
 479
 480                                         if (!IsValidCallerContext (rc.CurrentMemberDefinition)) {
 481                                                 rc.Report.Warning (4025, 1, attr.Location,
 482                                                         "The CallerFilePath applied to parameter `{0}' will have no effect because it applies to a member that is used in context that do not allow optional arguments",
 483                                                         name);
 484                                         }
 485
 486                                         modFlags |= Modifier.CallerFilePath;
 487                                         callerFilePath = attr;
 488                                         continue;
 489                                 }
 490                         }
 491
 492                         if ((modFlags & Modifier.CallerLineNumber) != 0) {
 493                                 if (callerMemberName != null) {
 494                                         rc.Report.Warning (7081, 1, callerMemberName.Location,
 495                                                 "The CallerMemberNameAttribute applied to parameter `{0}' will have no effect. It is overridden by the CallerLineNumberAttribute",
 496                                                 Name);
 497                                 }
 498
 499                                 if (callerFilePath != null) {
 500                                         rc.Report.Warning (7082, 1, callerFilePath.Location,
 501                                                 "The CallerFilePathAttribute applied to parameter `{0}' will have no effect. It is overridden by the CallerLineNumberAttribute",
 502                                                 name);
 503                                 }
 504                         }
 505
 506                         if ((modFlags & Modifier.CallerMemberName) != 0) {
 507                                 if (callerFilePath != null) {
 508                                         rc.Report.Warning (7080, 1, callerFilePath.Location,
 509                                                 "The CallerMemberNameAttribute applied to parameter `{0}' will have no effect. It is overridden by the CallerFilePathAttribute",
 510                                                 name);
 511                                 }
 512
 513                         }
 514                 }
 515
 516                 public void ResolveDefaultValue (ResolveContext rc)
 517                 {
 518                         //
 519                         // Default value was specified using an expression
 520                         //
 521                         if (default_expr != null) {
 522                                 ((DefaultParameterValueExpression)default_expr).Resolve (rc, this);
 523                                 if (attributes != null)
 524                                         ResolveCallerAttributes (rc);
 525
 526                                 return;
 527                         }
 528
 529                         if (attributes == null)
 530                                 return;
 531
 532                         var pa = rc.Module.PredefinedAttributes;
 533                         var def_attr = attributes.Search (pa.DefaultParameterValue);
 534                         if (def_attr != null) {
 535                                 if (def_attr.Resolve () == null)
 536                                         return;
 537
 538                                 var default_expr_attr = def_attr.GetParameterDefaultValue ();
 539                                 if (default_expr_attr == null)
 540                                         return;
 541
 542                                 var dpa_rc = def_attr.CreateResolveContext ();
 543                                 default_expr = default_expr_attr.Resolve (dpa_rc);
 544
 545                                 if (default_expr is BoxedCast)
 546                                         default_expr = ((BoxedCast) default_expr).Child;
 547
 548                                 Constant c = default_expr as Constant;
 549                                 if (c == null) {
 550                                         if (parameter_type.BuiltinType == BuiltinTypeSpec.Type.Object) {
 551                                                 rc.Report.Error (1910, default_expr.Location,
 552                                                         "Argument of type `{0}' is not applicable for the DefaultParameterValue attribute",
 553                                                         default_expr.Type.GetSignatureForError ());
 554                                         } else {
 555                                                 rc.Report.Error (1909, default_expr.Location,
 556                                                         "The DefaultParameterValue attribute is not applicable on parameters of type `{0}'",
 557                                                         default_expr.Type.GetSignatureForError ());
 558                                         }
 559
 560                                         default_expr = null;
 561                                         return;
 562                                 }
 563
 564                                 if (TypeSpecComparer.IsEqual (default_expr.Type, parameter_type) ||
 565                                         (default_expr is NullConstant && TypeSpec.IsReferenceType (parameter_type) && !parameter_type.IsGenericParameter) ||
 566                                         parameter_type.BuiltinType == BuiltinTypeSpec.Type.Object) {
 567                                         return;
 568                                 }
 569
 570                                 //
 571                                 // LAMESPEC: Some really weird csc behaviour which we have to mimic
 572                                 // User operators returning same type as parameter type are considered
 573                                 // valid for this attribute only
 574                                 //
 575                                 // struct S { public static implicit operator S (int i) {} }
 576                                 //
 577                                 // void M ([DefaultParameterValue (3)]S s)
 578                                 //
 579                                 var expr = Convert.ImplicitUserConversion (dpa_rc, default_expr, parameter_type, loc);
 580                                 if (expr != null && TypeSpecComparer.IsEqual (expr.Type, parameter_type)) {
 581                                         return;
 582                                 }
 583
 584                                 rc.Report.Error (1908, default_expr.Location, "The type of the default value should match the type of the parameter");
 585                                 return;
 586                         }
 587
 588                         var opt_attr = attributes.Search (pa.OptionalParameter);
 589                         if (opt_attr != null) {
 590                                 default_expr = EmptyExpression.MissingValue;
 591                         }
 592                 }
 593
 594                 public bool HasDefaultValue {
 595                         get { return default_expr != null; }
 596                 }
 597
 598                 public bool HasExtensionMethodModifier {
 599                         get { return (modFlags & Modifier.This) != 0; }
 600                 }
 601
 602                 //
 603                 // Hoisted parameter variant
 604                 //
 605                 public HoistedParameter HoistedVariant {
 606                         get {
 607                                 return hoisted_variant;
 608                         }
 609                         set {
 610                                 hoisted_variant = value;
 611                         }
 612                 }
 613
 614                 public Modifier ModFlags {
 615                         get { return modFlags & ~Modifier.This; }
 616                 }
 617
 618                 public string Name {
 619                         get { return name; }
 620                         set { name = value; }
 621                 }
 622
 623                 public override AttributeTargets AttributeTargets {
 624                         get {
 625                                 return AttributeTargets.Parameter;
 626                         }
 627                 }
 628
 629                 public void Error_DuplicateName (Report r)
 630                 {
 631                         r.Error (100, Location, "The parameter name `{0}' is a duplicate", Name);
 632                 }
 633
 634                 public virtual string GetSignatureForError ()
 635                 {
 636                         string type_name;
 637                         if (parameter_type != null)
 638                                 type_name = parameter_type.GetSignatureForError ();
 639                         else
 640                                 type_name = texpr.GetSignatureForError ();
 641
 642                         string mod = GetModifierSignature (modFlags);
 643                         if (mod.Length > 0)
 644                                 return String.Concat (mod, " ", type_name);
 645
 646                         return type_name;
 647                 }
 648
 649                 public static string GetModifierSignature (Modifier mod)
 650                 {
 651                         switch (mod) {
 652                         case Modifier.OUT:
 653                                 return "out";
 654                         case Modifier.PARAMS:
 655                                 return "params";
 656                         case Modifier.REF:
 657                                 return "ref";
 658                         case Modifier.This:
 659                                 return "this";
 660                         default:
 661                                 return "";
 662                         }
 663                 }
 664
 665                 public void IsClsCompliant (IMemberContext ctx)
 666                 {
 667                         if (parameter_type.IsCLSCompliant ())
 668                                 return;
 669
 670                         ctx.Module.Compiler.Report.Warning (3001, 1, Location,
 671                                 "Argument type `{0}' is not CLS-compliant", parameter_type.GetSignatureForError ());
 672                 }
 673
 674                 public virtual void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index, PredefinedAttributes pa)
 675                 {
 676                         if (builder != null)
 677                                 throw new InternalErrorException ("builder already exists");
 678
 679                         var pattrs = ParametersCompiled.GetParameterAttribute (modFlags);
 680                         if (HasOptionalExpression)
 681                                 pattrs |= ParameterAttributes.Optional;
 682
 683                         if (mb == null)
 684                                 builder = cb.DefineParameter (index, pattrs, Name);
 685                         else
 686                                 builder = mb.DefineParameter (index, pattrs, Name);
 687
 688                         if (OptAttributes != null)
 689                                 OptAttributes.Emit ();
 690
 691                         if (HasDefaultValue && default_expr.Type != null) {
 692                                 //
 693                                 // Emit constant values for true constants only, the other
 694                                 // constant-like expressions will rely on default value expression
 695                                 //
 696                                 var def_value = DefaultValue;
 697                                 Constant c = def_value != null ? def_value.Child as Constant : default_expr as Constant;
 698                                 if (c != null) {
 699                                         if (c.Type.BuiltinType == BuiltinTypeSpec.Type.Decimal) {
 700                                                 pa.DecimalConstant.EmitAttribute (builder, (decimal) c.GetValue (), c.Location);
 701                                         } else {
 702                                                 builder.SetConstant (c.GetValue ());
 703                                         }
 704                                 } else if (default_expr.Type.IsStruct || default_expr.Type.IsGenericParameter) {
 705                                         //
 706                                         // Handles special case where default expression is used with value-type or type parameter
 707                                         //
 708                                         // void Foo (S s = default (S)) {}
 709                                         //
 710                                         builder.SetConstant (null);
 711                                 }
 712                         }
 713
 714                         if (parameter_type != null) {
 715                                 if (parameter_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
 716                                         pa.Dynamic.EmitAttribute (builder);
 717                                 } else if (parameter_type.HasDynamicElement) {
 718                                         pa.Dynamic.EmitAttribute (builder, parameter_type, Location);
 719                                 }
 720                         }
 721                 }
 722
 723                 public Parameter Clone ()
 724                 {
 725                         Parameter p = (Parameter) MemberwiseClone ();
 726                         if (attributes != null)
 727                                 p.attributes = attributes.Clone ();
 728
 729                         return p;
 730                 }
 731
 732                 public ExpressionStatement CreateExpressionTreeVariable (BlockContext ec)
 733                 {
 734                         if ((modFlags & Modifier.RefOutMask) != 0)
 735                                 ec.Report.Error (1951, Location, "An expression tree parameter cannot use `ref' or `out' modifier");
 736
 737                         expr_tree_variable = TemporaryVariableReference.Create (ResolveParameterExpressionType (ec, Location).Type, ec.CurrentBlock.ParametersBlock, Location);
 738                         expr_tree_variable = (TemporaryVariableReference) expr_tree_variable.Resolve (ec);
 739
 740                         Arguments arguments = new Arguments (2);
 741                         arguments.Add (new Argument (new TypeOf (parameter_type, Location)));
 742                         arguments.Add (new Argument (new StringConstant (ec.BuiltinTypes, Name, Location)));
 743                         return new SimpleAssign (ExpressionTreeVariableReference (),
 744                                 Expression.CreateExpressionFactoryCall (ec, "Parameter", null, arguments, Location));
 745                 }
 746
 747                 public void Emit (EmitContext ec)
 748                 {
 749                         ec.EmitArgumentLoad (idx);
 750                 }
 751
 752                 public void EmitAssign (EmitContext ec)
 753                 {
 754                         ec.EmitArgumentStore (idx);
 755                 }
 756
 757                 public void EmitAddressOf (EmitContext ec)
 758                 {
 759                         if ((ModFlags & Modifier.RefOutMask) != 0) {
 760                                 ec.EmitArgumentLoad (idx);
 761                         } else {
 762                                 ec.EmitArgumentAddress (idx);
 763                         }
 764                 }
 765
 766                 public TemporaryVariableReference ExpressionTreeVariableReference ()
 767                 {
 768                         return expr_tree_variable;
 769                 }
 770
 771                 //
 772                 // System.Linq.Expressions.ParameterExpression type
 773                 //
 774                 public static TypeExpr ResolveParameterExpressionType (IMemberContext ec, Location location)
 775                 {
 776                         TypeSpec p_type = ec.Module.PredefinedTypes.ParameterExpression.Resolve ();
 777                         return new TypeExpression (p_type, location);
 778                 }
 779
 780                 public void SetIndex (int index)
 781                 {
 782                         idx = index;
 783                 }
 784
 785                 public void Warning_UselessOptionalParameter (Report Report)
 786                 {
 787                         Report.Warning (1066, 1, Location,
 788                                 "The default value specified for optional parameter `{0}' will never be used",
 789                                 Name);
 790                 }
 791         }
 792
 793         //
 794         // Imported or resolved parameter information
 795         //
 796         public class ParameterData : IParameterData
 797         {
 798                 readonly string name;
 799                 readonly Parameter.Modifier modifiers;
 800                 readonly Expression default_value;
 801
 802                 public ParameterData (string name, Parameter.Modifier modifiers)
 803                 {
 804                         this.name = name;
 805                         this.modifiers = modifiers;
 806                 }
 807
 808                 public ParameterData (string name, Parameter.Modifier modifiers, Expression defaultValue)
 809                         : this (name, modifiers)
 810                 {
 811                         this.default_value = defaultValue;
 812                 }
 813
 814                 #region IParameterData Members
 815
 816                 public Expression DefaultValue {
 817                         get { return default_value; }
 818                 }
 819
 820                 public bool HasExtensionMethodModifier {
 821                         get { return (modifiers & Parameter.Modifier.This) != 0; }
 822                 }
 823
 824                 public bool HasDefaultValue {
 825                         get { return default_value != null; }
 826                 }
 827
 828                 public Parameter.Modifier ModFlags {
 829                         get { return modifiers; }
 830                 }
 831
 832                 public string Name {
 833                         get { return name; }
 834                 }
 835
 836                 #endregion
 837         }
 838
 839         public abstract class AParametersCollection
 840         {
 841                 protected bool has_arglist;
 842                 protected bool has_params;
 843
 844                 // Null object pattern
 845                 protected IParameterData [] parameters;
 846                 protected TypeSpec [] types;
 847
 848                 public CallingConventions CallingConvention {
 849                         get {
 850                                 return has_arglist ?
 851                                         CallingConventions.VarArgs :
 852                                         CallingConventions.Standard;
 853                         }
 854                 }
 855
 856                 public int Count {
 857                         get { return parameters.Length; }
 858                 }
 859
 860                 public TypeSpec ExtensionMethodType {
 861                         get {
 862                                 if (Count == 0)
 863                                         return null;
 864
 865                                 return FixedParameters [0].HasExtensionMethodModifier ?
 866                                         types [0] : null;
 867                         }
 868                 }
 869
 870                 public IParameterData [] FixedParameters {
 871                         get {
 872                                 return parameters;
 873                         }
 874                 }
 875
 876                 public static ParameterAttributes GetParameterAttribute (Parameter.Modifier modFlags)
 877                 {
 878                         return (modFlags & Parameter.Modifier.OUT) != 0 ?
 879                                 ParameterAttributes.Out : ParameterAttributes.None;
 880                 }
 881
 882                 // Very expensive operation
 883                 public MetaType[] GetMetaInfo ()
 884                 {
 885                         MetaType[] types;
 886                         if (has_arglist) {
 887                                 if (Count == 1)
 888                                         return MetaType.EmptyTypes;
 889
 890                                 types = new MetaType[Count - 1];
 891                         } else {
 892                                 if (Count == 0)
 893                                         return MetaType.EmptyTypes;
 894
 895                                 types = new MetaType[Count];
 896                         }
 897
 898                         for (int i = 0; i < types.Length; ++i) {
 899                                 types[i] = Types[i].GetMetaInfo ();
 900
 901                                 if ((FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask) == 0)
 902                                         continue;
 903
 904                                 // TODO MemberCache: Should go to MetaInfo getter
 905                                 types [i] = types [i].MakeByRefType ();
 906                         }
 907
 908                         return types;
 909                 }
 910
 911                 //
 912                 // Returns the parameter information based on the name
 913                 //
 914                 public int GetParameterIndexByName (string name)
 915                 {
 916                         for (int idx = 0; idx < Count; ++idx) {
 917                                 if (parameters [idx].Name == name)
 918                                         return idx;
 919                         }
 920
 921                         return -1;
 922                 }
 923
 924                 public string GetSignatureForDocumentation ()
 925                 {
 926                         if (IsEmpty)
 927                                 return string.Empty;
 928
 929                         StringBuilder sb = new StringBuilder ("(");
 930                         for (int i = 0; i < Count; ++i) {
 931                                 if (i != 0)
 932                                         sb.Append (",");
 933
 934                                 sb.Append (types [i].GetSignatureForDocumentation ());
 935
 936                                 if ((parameters[i].ModFlags & Parameter.Modifier.RefOutMask) != 0)
 937                                         sb.Append ("@");
 938                         }
 939                         sb.Append (")");
 940
 941                         return sb.ToString ();
 942                 }
 943
 944                 public string GetSignatureForError ()
 945                 {
 946                         return GetSignatureForError ("(", ")", Count);
 947                 }
 948
 949                 public string GetSignatureForError (string start, string end, int count)
 950                 {
 951                         StringBuilder sb = new StringBuilder (start);
 952                         for (int i = 0; i < count; ++i) {
 953                                 if (i != 0)
 954                                         sb.Append (", ");
 955                                 sb.Append (ParameterDesc (i));
 956                         }
 957                         sb.Append (end);
 958                         return sb.ToString ();
 959                 }
 960
 961                 public bool HasArglist {
 962                         get { return has_arglist; }
 963                 }
 964
 965                 public bool HasExtensionMethodType {
 966                         get {
 967                                 if (Count == 0)
 968                                         return false;
 969
 970                                 return FixedParameters [0].HasExtensionMethodModifier;
 971                         }
 972                 }
 973
 974                 public bool HasParams {
 975                         get { return has_params; }
 976                 }
 977
 978                 public bool IsEmpty {
 979                         get { return parameters.Length == 0; }
 980                 }
 981
 982                 public AParametersCollection Inflate (TypeParameterInflator inflator)
 983                 {
 984                         TypeSpec[] inflated_types = null;
 985                         bool default_value = false;
 986
 987                         for (int i = 0; i < Count; ++i) {
 988                                 var inflated_param = inflator.Inflate (types[i]);
 989                                 if (inflated_types == null) {
 990                                         if (inflated_param == types[i])
 991                                                 continue;
 992
 993                                         default_value |= FixedParameters[i].HasDefaultValue;
 994                                         inflated_types = new TypeSpec[types.Length];
 995                                         Array.Copy (types, inflated_types, types.Length);
 996                                 } else {
 997                                         if (inflated_param == types[i])
 998                                                 continue;
 999
1000                                         default_value |= FixedParameters[i].HasDefaultValue;
1001                                 }
1002
1003                                 inflated_types[i] = inflated_param;
1004                         }
1005
1006                         if (inflated_types == null)
1007                                 return this;
1008
1009                         var clone = (AParametersCollection) MemberwiseClone ();
1010                         clone.types = inflated_types;
1011
1012                         //
1013                         // Default expression is original expression from the parameter
1014                         // declaration context which can be of nested enum in generic class type.
1015                         // In such case we end up with expression type of G<T>.E and e.g. parameter
1016                         // type of G<int>.E and conversion would fail without inflate in this
1017                         // context.
1018                         //
1019                         if (default_value) {
1020                                 clone.parameters = new IParameterData[Count];
1021                                 for (int i = 0; i < Count; ++i) {
1022                                         var fp = FixedParameters[i];
1023                                         clone.FixedParameters[i] = fp;
1024
1025                                         if (!fp.HasDefaultValue)
1026                                                 continue;
1027
1028                                         var expr = fp.DefaultValue;
1029
1030                                         if (inflated_types[i] == expr.Type)
1031                                                 continue;
1032
1033                                         var c = expr as Constant;
1034                                         if (c != null) {
1035                                                 //
1036                                                 // It may fail we are inflating before type validation is done
1037                                                 //
1038                                                 c = Constant.ExtractConstantFromValue (inflated_types[i], c.GetValue (), expr.Location);
1039                                                 if (c == null)
1040                                                         expr = new DefaultValueExpression (new TypeExpression (inflated_types[i], expr.Location), expr.Location);
1041                                                 else
1042                                                         expr = c;
1043                                         } else if (expr is DefaultValueExpression)
1044                                                 expr = new DefaultValueExpression (new TypeExpression (inflated_types[i], expr.Location), expr.Location);
1045
1046                                         clone.FixedParameters[i] = new ParameterData (fp.Name, fp.ModFlags, expr);
1047                                 }
1048                         }
1049
1050                         return clone;
1051                 }
1052
1053                 public string ParameterDesc (int pos)
1054                 {
1055                         if (types == null || types [pos] == null)
1056                                 return ((Parameter)FixedParameters [pos]).GetSignatureForError ();
1057
1058                         string type = types [pos].GetSignatureForError ();
1059                         if (FixedParameters [pos].HasExtensionMethodModifier)
1060                                 return "this " + type;
1061
1062                         var mod = FixedParameters[pos].ModFlags & Parameter.Modifier.ModifierMask;
1063                         if (mod == 0)
1064                                 return type;
1065
1066                         return Parameter.GetModifierSignature (mod) + " " + type;
1067                 }
1068
1069                 public TypeSpec[] Types {
1070                         get { return types; }
1071                         set { types = value; }
1072                 }
1073         }
1074
1075         //
1076         // A collection of imported or resolved parameters
1077         //
1078         public class ParametersImported : AParametersCollection
1079         {
1080                 public ParametersImported (IParameterData [] parameters, TypeSpec [] types, bool hasArglist, bool hasParams)
1081                 {
1082                         this.parameters = parameters;
1083                         this.types = types;
1084                         this.has_arglist = hasArglist;
1085                         this.has_params = hasParams;
1086                 }
1087
1088                 public ParametersImported (IParameterData[] param, TypeSpec[] types, bool hasParams)
1089                 {
1090                         this.parameters = param;
1091                         this.types = types;
1092                         this.has_params = hasParams;
1093                 }
1094         }
1095
1096         /// <summary>
1097         ///   Represents the methods parameters
1098         /// </summary>
1099         public class ParametersCompiled : AParametersCollection
1100         {
1101                 public static readonly ParametersCompiled EmptyReadOnlyParameters = new ParametersCompiled ();
1102
1103                 // Used by C# 2.0 delegates
1104                 public static readonly ParametersCompiled Undefined = new ParametersCompiled ();
1105
1106                 private ParametersCompiled ()
1107                 {
1108                         parameters = new Parameter [0];
1109                         types = TypeSpec.EmptyTypes;
1110                 }
1111
1112                 private ParametersCompiled (IParameterData[] parameters, TypeSpec[] types)
1113                 {
1114                         this.parameters = parameters;
1115                     this.types = types;
1116                 }
1117
1118                 public ParametersCompiled (params Parameter[] parameters)
1119                 {
1120                         if (parameters == null || parameters.Length == 0)
1121                                 throw new ArgumentException ("Use EmptyReadOnlyParameters");
1122
1123                         this.parameters = parameters;
1124                         int count = parameters.Length;
1125
1126                         for (int i = 0; i < count; i++){
1127                                 has_params |= (parameters [i].ModFlags & Parameter.Modifier.PARAMS) != 0;
1128                         }
1129                 }
1130
1131                 public ParametersCompiled (Parameter [] parameters, bool has_arglist) :
1132                         this (parameters)
1133                 {
1134                         this.has_arglist = has_arglist;
1135                 }
1136
1137                 public static ParametersCompiled CreateFullyResolved (Parameter p, TypeSpec type)
1138                 {
1139                         return new ParametersCompiled (new Parameter [] { p }, new TypeSpec [] { type });
1140                 }
1141
1142                 public static ParametersCompiled CreateFullyResolved (Parameter[] parameters, TypeSpec[] types)
1143                 {
1144                         return new ParametersCompiled (parameters, types);
1145                 }
1146
1147                 public static ParametersCompiled Prefix (ParametersCompiled parameters, Parameter p, TypeSpec type)
1148                 {
1149                         var ptypes = new TypeSpec [parameters.Count + 1];
1150                         ptypes [0] = type;
1151                         Array.Copy (parameters.Types, 0, ptypes, 1, parameters.Count);
1152
1153                         var param = new Parameter [ptypes.Length];
1154                         param [0] = p;
1155                         for (int i = 0; i < parameters.Count; ++i) {
1156                                 var pi = parameters [i];
1157                                 param [i + 1] = pi;
1158                                 pi.SetIndex (i + 1);
1159                         }
1160
1161                         return ParametersCompiled.CreateFullyResolved (param, ptypes);
1162                 }
1163
1164                 //
1165                 // TODO: This does not fit here, it should go to different version of AParametersCollection
1166                 // as the underlying type is not Parameter and some methods will fail to cast
1167                 //
1168                 public static AParametersCollection CreateFullyResolved (params TypeSpec[] types)
1169                 {
1170                         var pd = new ParameterData [types.Length];
1171                         for (int i = 0; i < pd.Length; ++i)
1172                                 pd[i] = new ParameterData (null, Parameter.Modifier.NONE, null);
1173
1174                         return new ParametersCompiled (pd, types);
1175                 }
1176
1177                 public static ParametersCompiled CreateImplicitParameter (FullNamedExpression texpr, Location loc)
1178                 {
1179                         return new ParametersCompiled (
1180                                 new[] { new Parameter (texpr, "value", Parameter.Modifier.NONE, null, loc) },
1181                                 null);
1182                 }
1183
1184                 public void CheckConstraints (IMemberContext mc)
1185                 {
1186                         foreach (Parameter p in parameters) {
1187                                 //
1188                                 // It's null for compiler generated types or special types like __arglist
1189                                 //
1190                                 if (p.TypeExpression != null)
1191                                         ConstraintChecker.Check (mc, p.Type, p.TypeExpression.Location);
1192                         }
1193                 }
1194
1195                 //
1196                 // Returns non-zero value for equal CLS parameter signatures
1197                 //
1198                 public static int IsSameClsSignature (AParametersCollection a, AParametersCollection b)
1199                 {
1200                         int res = 0;
1201
1202                         for (int i = 0; i < a.Count; ++i) {
1203                                 var a_type = a.Types[i];
1204                                 var b_type = b.Types[i];
1205                                 if (TypeSpecComparer.Override.IsEqual (a_type, b_type)) {
1206                                         if ((a.FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask) != (b.FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask))
1207                                                 res |= 1;
1208
1209                                         continue;
1210                                 }
1211
1212                                 var ac_a = a_type as ArrayContainer;
1213                                 if (ac_a == null)
1214                                         return 0;
1215
1216                                 var ac_b = b_type as ArrayContainer;
1217                                 if (ac_b == null)
1218                                         return 0;
1219
1220                                 if (ac_a.Element is ArrayContainer || ac_b.Element is ArrayContainer) {
1221                                         res |= 2;
1222                                         continue;
1223                                 }
1224
1225                                 if (ac_a.Rank != ac_b.Rank && TypeSpecComparer.Override.IsEqual (ac_a.Element, ac_b.Element)) {
1226                                         res |= 1;
1227                                         continue;
1228                                 }
1229
1230                                 return 0;
1231                         }
1232
1233                         return res;
1234                 }
1235
1236                 public static ParametersCompiled MergeGenerated (CompilerContext ctx, ParametersCompiled userParams, bool checkConflicts, Parameter compilerParams, TypeSpec compilerTypes)
1237                 {
1238                         return MergeGenerated (ctx, userParams, checkConflicts,
1239                                 new Parameter [] { compilerParams },
1240                                 new TypeSpec [] { compilerTypes });
1241                 }
1242
1243                 //
1244                 // Use this method when you merge compiler generated parameters with user parameters
1245                 //
1246                 public static ParametersCompiled MergeGenerated (CompilerContext ctx, ParametersCompiled userParams, bool checkConflicts, Parameter[] compilerParams, TypeSpec[] compilerTypes)
1247                 {
1248                         Parameter[] all_params = new Parameter [userParams.Count + compilerParams.Length];
1249                         userParams.FixedParameters.CopyTo(all_params, 0);
1250
1251                         TypeSpec [] all_types;
1252                         if (userParams.types != null) {
1253                                 all_types = new TypeSpec [all_params.Length];
1254                                 userParams.Types.CopyTo (all_types, 0);
1255                         } else {
1256                                 all_types = null;
1257                         }
1258
1259                         int last_filled = userParams.Count;
1260                         int index = 0;
1261                         foreach (Parameter p in compilerParams) {
1262                                 for (int i = 0; i < last_filled; ++i) {
1263                                         while (p.Name == all_params [i].Name) {
1264                                                 if (checkConflicts && i < userParams.Count) {
1265                                                         ctx.Report.Error (316, userParams[i].Location,
1266                                                                 "The parameter name `{0}' conflicts with a compiler generated name", p.Name);
1267                                                 }
1268                                                 p.Name = '_' + p.Name;
1269                                         }
1270                                 }
1271                                 all_params [last_filled] = p;
1272                                 if (all_types != null)
1273                                         all_types [last_filled] = compilerTypes [index++];
1274                                 ++last_filled;
1275                         }
1276
1277                         ParametersCompiled parameters = new ParametersCompiled (all_params, all_types);
1278                         parameters.has_params = userParams.has_params;
1279                         return parameters;
1280                 }
1281
1282                 //
1283                 // Parameters checks for members which don't have a block
1284                 //
1285                 public void CheckParameters (MemberCore member)
1286                 {
1287                         for (int i = 0; i < parameters.Length; ++i) {
1288                                 var name = parameters[i].Name;
1289                                 for (int ii = i + 1; ii < parameters.Length; ++ii) {
1290                                         if (parameters[ii].Name == name)
1291                                                 this[ii].Error_DuplicateName (member.Compiler.Report);
1292                                 }
1293                         }
1294                 }
1295
1296                 public bool Resolve (IMemberContext ec)
1297                 {
1298                         if (types != null)
1299                                 return true;
1300
1301                         types = new TypeSpec [Count];
1302
1303                         bool ok = true;
1304                         Parameter p;
1305                         for (int i = 0; i < FixedParameters.Length; ++i) {
1306                                 p = this [i];
1307                                 TypeSpec t = p.Resolve (ec, i);
1308                                 if (t == null) {
1309                                         ok = false;
1310                                         continue;
1311                                 }
1312
1313                                 types [i] = t;
1314                         }
1315
1316                         return ok;
1317                 }
1318
1319                 public void ResolveDefaultValues (MemberCore m)
1320                 {
1321                         ResolveContext rc = null;
1322                         for (int i = 0; i < parameters.Length; ++i) {
1323                                 Parameter p = (Parameter) parameters [i];
1324
1325                                 //
1326                                 // Try not to enter default values resolution if there are is not any default value possible
1327                                 //
1328                                 if (p.HasDefaultValue || p.OptAttributes != null) {
1329                                         if (rc == null)
1330                                                 rc = new ResolveContext (m);
1331
1332                                         p.ResolveDefaultValue (rc);
1333                                 }
1334                         }
1335                 }
1336
1337                 // Define each type attribute (in/out/ref) and
1338                 // the argument names.
1339                 public void ApplyAttributes (IMemberContext mc, MethodBase builder)
1340                 {
1341                         if (Count == 0)
1342                                 return;
1343
1344                         MethodBuilder mb = builder as MethodBuilder;
1345                         ConstructorBuilder cb = builder as ConstructorBuilder;
1346                         var pa = mc.Module.PredefinedAttributes;
1347
1348                         for (int i = 0; i < Count; i++) {
1349                                 this [i].ApplyAttributes (mb, cb, i + 1, pa);
1350                         }
1351                 }
1352
1353                 public void VerifyClsCompliance (IMemberContext ctx)
1354                 {
1355                         foreach (Parameter p in FixedParameters)
1356                                 p.IsClsCompliant (ctx);
1357                 }
1358
1359                 public Parameter this [int pos] {
1360                         get { return (Parameter) parameters [pos]; }
1361                 }
1362
1363                 public Expression CreateExpressionTree (BlockContext ec, Location loc)
1364                 {
1365                         var initializers = new ArrayInitializer (Count, loc);
1366                         foreach (Parameter p in FixedParameters) {
1367                                 //
1368                                 // Each parameter expression is stored to local variable
1369                                 // to save some memory when referenced later.
1370                                 //
1371                                 StatementExpression se = new StatementExpression (p.CreateExpressionTreeVariable (ec), Location.Null);
1372                                 if (se.Resolve (ec)) {
1373                                         ec.CurrentBlock.AddScopeStatement (new TemporaryVariableReference.Declarator (p.ExpressionTreeVariableReference ()));
1374                                         ec.CurrentBlock.AddScopeStatement (se);
1375                                 }
1376
1377                                 initializers.Add (p.ExpressionTreeVariableReference ());
1378                         }
1379
1380                         return new ArrayCreation (
1381                                 Parameter.ResolveParameterExpressionType (ec, loc),
1382                                 initializers, loc);
1383                 }
1384
1385                 public ParametersCompiled Clone ()
1386                 {
1387                         ParametersCompiled p = (ParametersCompiled) MemberwiseClone ();
1388
1389                         p.parameters = new IParameterData [parameters.Length];
1390                         for (int i = 0; i < Count; ++i)
1391                                 p.parameters [i] = this [i].Clone ();
1392
1393                         return p;
1394                 }
1395         }
1396
1397         //
1398         // Default parameter value expression. We need this wrapper to handle
1399         // default parameter values of folded constants (e.g. indexer parameters).
1400         // The expression is resolved only once but applied to two methods which
1401         // both share reference to this expression and we ensure that resolving
1402         // this expression always returns same instance
1403         //
1404         public class DefaultParameterValueExpression : CompositeExpression
1405         {
1406                 public DefaultParameterValueExpression (Expression expr)
1407                         : base (expr)
1408                 {
1409                 }
1410
1411                 public void Resolve (ResolveContext rc, Parameter p)
1412                 {
1413                         var expr = Resolve (rc);
1414                         if (expr == null) {
1415                                 this.expr = ErrorExpression.Instance;
1416                                 return;
1417                         }
1418
1419                         expr = Child;
1420
1421                         if (!(expr is Constant || expr is DefaultValueExpression || (expr is New && ((New) expr).IsGeneratedStructConstructor))) {
1422                                 if (!(expr is ErrorExpression)) {
1423                                         rc.Report.Error (1736, Location,
1424                                                 "The expression being assigned to optional parameter `{0}' must be a constant or default value",
1425                                                 p.Name);
1426                                 }
1427
1428                                 return;
1429                         }
1430
1431                         var parameter_type = p.Type;
1432                         if (type == parameter_type)
1433                                 return;
1434
1435                         var res = Convert.ImplicitConversionStandard (rc, expr, parameter_type, Location);
1436                         if (res != null) {
1437                                 if (parameter_type.IsNullableType && res is Nullable.Wrap) {
1438                                         Nullable.Wrap wrap = (Nullable.Wrap) res;
1439                                         res = wrap.Child;
1440                                         if (!(res is Constant)) {
1441                                                 rc.Report.Error (1770, Location,
1442                                                         "The expression being assigned to nullable optional parameter `{0}' must be default value",
1443                                                         p.Name);
1444                                                 return;
1445                                         }
1446                                 }
1447
1448                                 if (!expr.IsNull && TypeSpec.IsReferenceType (parameter_type) && parameter_type.BuiltinType != BuiltinTypeSpec.Type.String) {
1449                                         rc.Report.Error (1763, Location,
1450                                                 "Optional parameter `{0}' of type `{1}' can only be initialized with `null'",
1451                                                 p.Name, parameter_type.GetSignatureForError ());
1452
1453                                         return;
1454                                 }
1455
1456                                 this.expr = res;
1457                                 return;
1458                         }
1459
1460                         rc.Report.Error (1750, Location,
1461                                 "Optional parameter expression of type `{0}' cannot be converted to parameter type `{1}'",
1462                                 type.GetSignatureForError (), parameter_type.GetSignatureForError ());
1463
1464                         this.expr = ErrorExpression.Instance;
1465                 }
1466
1467                 public override object Accept (StructuralVisitor visitor)
1468                 {
1469                         return visitor.Visit (this);
1470                 }
1471         }
1472 }