mcs/gmcs/generic.cs

   1 //
   2 // generic.cs: Generics support
   3 //
   4 // Authors: Martin Baulig (martin@ximian.com)
   5 //          Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // Licensed under the terms of the GNU GPL
   8 //
   9 // (C) 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
  10 // (C) 2004 Novell, Inc
  11 //
  12 using System;
  13 using System.Reflection;
  14 using System.Reflection.Emit;
  15 using System.Globalization;
  16 using System.Collections;
  17 using System.Text;
  18 using System.Text.RegularExpressions;
  19
  20 namespace Mono.CSharp {
  21
  22         public abstract class GenericConstraints {
  23                 public abstract GenericParameterAttributes Attributes {
  24                         get;
  25                 }
  26
  27                 public bool HasConstructorConstraint {
  28                         get { return (Attributes & GenericParameterAttributes.DefaultConstructorConstraint) != 0; }
  29                 }
  30
  31                 public bool HasReferenceTypeConstraint {
  32                         get { return (Attributes & GenericParameterAttributes.ReferenceTypeConstraint) != 0; }
  33                 }
  34
  35                 public bool HasValueTypeConstraint {
  36                         get { return (Attributes & GenericParameterAttributes.ValueTypeConstraint) != 0; }
  37                 }
  38
  39                 public virtual bool HasClassConstraint {
  40                         get { return ClassConstraint != null; }
  41                 }
  42
  43                 public abstract Type ClassConstraint {
  44                         get;
  45                 }
  46
  47                 public abstract Type[] InterfaceConstraints {
  48                         get;
  49                 }
  50
  51                 public abstract Type EffectiveBaseClass {
  52                         get;
  53                 }
  54
  55                 // <summary>
  56                 //   Returns whether the type parameter is "known to be a reference type".
  57                 // </summary>
  58                 public virtual bool IsReferenceType {
  59                         get {
  60                                 if (HasReferenceTypeConstraint)
  61                                         return true;
  62                                 if (HasValueTypeConstraint)
  63                                         return false;
  64
  65                                 if (ClassConstraint != null) {
  66                                         if (ClassConstraint.IsValueType)
  67                                                 return false;
  68
  69                                         if (ClassConstraint != TypeManager.object_type)
  70                                                 return true;
  71                                 }
  72
  73                                 foreach (Type t in InterfaceConstraints) {
  74                                         if (!t.IsGenericParameter)
  75                                                 continue;
  76
  77                                         GenericConstraints gc = TypeManager.GetTypeParameterConstraints (t);
  78                                         if ((gc != null) && gc.IsReferenceType)
  79                                                 return true;
  80                                 }
  81
  82                                 return false;
  83                         }
  84                 }
  85
  86                 // <summary>
  87                 //   Returns whether the type parameter is "known to be a value type".
  88                 // </summary>
  89                 public virtual bool IsValueType {
  90                         get {
  91                                 if (HasValueTypeConstraint)
  92                                         return true;
  93                                 if (HasReferenceTypeConstraint)
  94                                         return false;
  95
  96                                 if (ClassConstraint != null) {
  97                                         if (!ClassConstraint.IsValueType)
  98                                                 return false;
  99
 100                                         if (ClassConstraint != TypeManager.value_type)
 101                                                 return true;
 102                                 }
 103
 104                                 foreach (Type t in InterfaceConstraints) {
 105                                         if (!t.IsGenericParameter)
 106                                                 continue;
 107
 108                                         GenericConstraints gc = TypeManager.GetTypeParameterConstraints (t);
 109                                         if ((gc != null) && gc.IsValueType)
 110                                                 return true;
 111                                 }
 112
 113                                 return false;
 114                         }
 115                 }
 116         }
 117
 118         public enum SpecialConstraint
 119         {
 120                 Constructor,
 121                 ReferenceType,
 122                 ValueType
 123         }
 124
 125         //
 126         // Tracks the constraints for a type parameter
 127         //
 128         public class Constraints : GenericConstraints {
 129                 string name;
 130                 ArrayList constraints;
 131                 Location loc;
 132
 133                 //
 134                 // name is the identifier, constraints is an arraylist of
 135                 // Expressions (with types) or `true' for the constructor constraint.
 136                 //
 137                 public Constraints (string name, ArrayList constraints,
 138                                     Location loc)
 139                 {
 140                         this.name = name;
 141                         this.constraints = constraints;
 142                         this.loc = loc;
 143                 }
 144
 145                 public string TypeParameter {
 146                         get {
 147                                 return name;
 148                         }
 149                 }
 150
 151                 GenericParameterAttributes attrs;
 152                 TypeExpr class_constraint;
 153                 ArrayList iface_constraints;
 154                 ArrayList type_param_constraints;
 155                 int num_constraints, first_constraint;
 156                 Type class_constraint_type;
 157                 Type[] iface_constraint_types;
 158                 Type effective_base_type;
 159
 160                 public bool Resolve (EmitContext ec)
 161                 {
 162                         iface_constraints = new ArrayList ();
 163                         type_param_constraints = new ArrayList ();
 164
 165                         foreach (object obj in constraints) {
 166                                 if (HasConstructorConstraint) {
 167                                         Report.Error (401, loc,
 168                                                       "The new() constraint must be last.");
 169                                         return false;
 170                                 }
 171
 172                                 if (obj is SpecialConstraint) {
 173                                         SpecialConstraint sc = (SpecialConstraint) obj;
 174
 175                                         if (sc == SpecialConstraint.Constructor) {
 176                                                 if (!HasValueTypeConstraint) {
 177                                                         attrs |= GenericParameterAttributes.DefaultConstructorConstraint;
 178                                                         continue;
 179                                                 }
 180
 181                                                 Report.Error (
 182                                                         451, loc, "The new () constraint " +
 183                                                         "cannot be used with the `struct' " +
 184                                                         "constraint.");
 185                                                 return false;
 186                                         }
 187
 188                                         if ((num_constraints > 0) || HasReferenceTypeConstraint || HasValueTypeConstraint) {
 189                                                 Report.Error (449, loc,
 190                                                               "The `class' or `struct' " +
 191                                                               "constraint must be first");
 192                                                 return false;
 193                                         }
 194
 195                                         if (sc == SpecialConstraint.ReferenceType)
 196                                                 attrs |= GenericParameterAttributes.ReferenceTypeConstraint;
 197                                         else
 198                                                 attrs |= GenericParameterAttributes.ValueTypeConstraint;
 199                                         continue;
 200                                 }
 201
 202                                 TypeExpr expr;
 203                                 if (obj is ConstructedType) {
 204                                         ConstructedType cexpr = (ConstructedType) obj;
 205                                         if (!cexpr.ResolveConstructedType (ec))
 206                                                 return false;
 207                                         expr = cexpr;
 208                                 } else
 209                                         expr = ((Expression) obj).ResolveAsTypeTerminal (ec);
 210
 211                                 if (expr == null)
 212                                         return false;
 213
 214                                 TypeParameterExpr texpr = expr as TypeParameterExpr;
 215                                 if (texpr != null)
 216                                         type_param_constraints.Add (expr);
 217                                 else if (expr.IsInterface)
 218                                         iface_constraints.Add (expr);
 219                                 else if (class_constraint != null) {
 220                                         Report.Error (406, loc,
 221                                                       "`{0}': the class constraint for `{1}' " +
 222                                                       "must come before any other constraints.",
 223                                                       expr.Name, name);
 224                                         return false;
 225                                 } else if (HasReferenceTypeConstraint || HasValueTypeConstraint) {
 226                                         Report.Error (450, loc, "`{0}': cannot specify both " +
 227                                                       "a constraint class and the `class' " +
 228                                                       "or `struct' constraint.", expr.Name);
 229                                         return false;
 230                                 } else
 231                                         class_constraint = expr;
 232
 233                                 num_constraints++;
 234                         }
 235
 236                         return true;
 237                 }
 238
 239                 bool CheckTypeParameterConstraints (TypeParameter tparam, Hashtable seen)
 240                 {
 241                         seen.Add (tparam, true);
 242
 243                         Constraints constraints = tparam.Constraints;
 244                         if (constraints == null)
 245                                 return true;
 246
 247                         if (constraints.HasValueTypeConstraint) {
 248                                 Report.Error (456, loc, "Type parameter `{0}' has " +
 249                                               "the `struct' constraint, so it cannot " +
 250                                               "be used as a constraint for `{1}'",
 251                                               tparam.Name, name);
 252                                 return false;
 253                         }
 254
 255                         if (constraints.type_param_constraints == null)
 256                                 return true;
 257
 258                         foreach (TypeParameterExpr expr in constraints.type_param_constraints) {
 259                                 if (seen.Contains (expr.TypeParameter)) {
 260                                         Report.Error (454, loc, "Circular constraint " +
 261                                                       "dependency involving `{0}' and `{1}'",
 262                                                       tparam.Name, expr.Name);
 263                                         return false;
 264                                 }
 265
 266                                 if (!CheckTypeParameterConstraints (expr.TypeParameter, seen))
 267                                         return false;
 268                         }
 269
 270                         return true;
 271                 }
 272
 273                 public bool ResolveTypes (EmitContext ec)
 274                 {
 275                         if (effective_base_type != null)
 276                                 return true;
 277
 278                         foreach (object obj in constraints) {
 279                                 ConstructedType cexpr = obj as ConstructedType;
 280                                 if (cexpr == null)
 281                                         continue;
 282
 283                                 if (!cexpr.CheckConstraints (ec))
 284                                         return false;
 285                         }
 286
 287                         foreach (TypeParameterExpr expr in type_param_constraints) {
 288                                 Hashtable seen = new Hashtable ();
 289                                 if (!CheckTypeParameterConstraints (expr.TypeParameter, seen))
 290                                         return false;
 291                         }
 292
 293                         ArrayList list = new ArrayList ();
 294
 295                         foreach (TypeExpr iface_constraint in iface_constraints) {
 296                                 foreach (Type type in list) {
 297                                         if (!type.Equals (iface_constraint.Type))
 298                                                 continue;
 299
 300                                         Report.Error (405, loc,
 301                                                       "Duplicate constraint `{0}' for type " +
 302                                                       "parameter `{1}'.", iface_constraint.Type,
 303                                                       name);
 304                                         return false;
 305                                 }
 306
 307                                 list.Add (iface_constraint.Type);
 308                         }
 309
 310                         foreach (TypeParameterExpr expr in type_param_constraints) {
 311                                 foreach (Type type in list) {
 312                                         if (!type.Equals (expr.Type))
 313                                                 continue;
 314
 315                                         Report.Error (405, loc,
 316                                                       "Duplicate constraint `{0}' for type " +
 317                                                       "parameter `{1}'.", expr.Type, name);
 318                                         return false;
 319                                 }
 320
 321                                 list.Add (expr.Type);
 322                         }
 323
 324                         iface_constraint_types = new Type [list.Count];
 325                         list.CopyTo (iface_constraint_types, 0);
 326
 327                         if (class_constraint != null) {
 328                                 class_constraint_type = class_constraint.Type;
 329                                 if (class_constraint_type == null)
 330                                         return false;
 331
 332                                 if (class_constraint_type.IsSealed) {
 333                                         Report.Error (701, loc,
 334                                                       "`{0}' is not a valid bound.  Bounds " +
 335                                                       "must be interfaces or non sealed " +
 336                                                       "classes", class_constraint_type);
 337                                         return false;
 338                                 }
 339
 340                                 if ((class_constraint_type == TypeManager.array_type) ||
 341                                     (class_constraint_type == TypeManager.delegate_type) ||
 342                                     (class_constraint_type == TypeManager.enum_type) ||
 343                                     (class_constraint_type == TypeManager.value_type) ||
 344                                     (class_constraint_type == TypeManager.object_type)) {
 345                                         Report.Error (702, loc,
 346                                                       "Bound cannot be special class `{0}'",
 347                                                       class_constraint_type);
 348                                         return false;
 349                                 }
 350                         }
 351
 352                         if (class_constraint_type != null)
 353                                 effective_base_type = class_constraint_type;
 354                         else if (HasValueTypeConstraint)
 355                                 effective_base_type = TypeManager.value_type;
 356                         else
 357                                 effective_base_type = TypeManager.object_type;
 358
 359                         return true;
 360                 }
 361
 362                 public bool CheckDependencies (EmitContext ec)
 363                 {
 364                         foreach (TypeParameterExpr expr in type_param_constraints) {
 365                                 if (!CheckDependencies (expr.TypeParameter, ec))
 366                                         return false;
 367                         }
 368
 369                         return true;
 370                 }
 371
 372                 bool CheckDependencies (TypeParameter tparam, EmitContext ec)
 373                 {
 374                         Constraints constraints = tparam.Constraints;
 375                         if (constraints == null)
 376                                 return true;
 377
 378                         if (HasValueTypeConstraint && constraints.HasClassConstraint) {
 379                                 Report.Error (455, loc, "Type parameter `{0}' inherits " +
 380                                               "conflicting constraints `{1}' and `{2}'",
 381                                               name, constraints.ClassConstraint,
 382                                               "System.ValueType");
 383                                 return false;
 384                         }
 385
 386                         if (HasClassConstraint && constraints.HasClassConstraint) {
 387                                 Type t1 = ClassConstraint;
 388                                 TypeExpr e1 = class_constraint;
 389                                 Type t2 = constraints.ClassConstraint;
 390                                 TypeExpr e2 = constraints.class_constraint;
 391
 392                                 if (!Convert.ImplicitReferenceConversionExists (ec, e1, t2) &&
 393                                     !Convert.ImplicitReferenceConversionExists (ec, e2, t1)) {
 394                                         Report.Error (455, loc,
 395                                                       "Type parameter `{0}' inherits " +
 396                                                       "conflicting constraints `{1}' and `{2}'",
 397                                                       name, t1, t2);
 398                                         return false;
 399                                 }
 400                         }
 401
 402                         if (constraints.type_param_constraints == null)
 403                                 return true;
 404
 405                         foreach (TypeParameterExpr expr in constraints.type_param_constraints) {
 406                                 if (!CheckDependencies (expr.TypeParameter, ec))
 407                                         return false;
 408                         }
 409
 410                         return true;
 411                 }
 412
 413                 public void Define (GenericTypeParameterBuilder type)
 414                 {
 415                         type.SetGenericParameterAttributes (attrs);
 416                 }
 417
 418                 public override GenericParameterAttributes Attributes {
 419                         get { return attrs; }
 420                 }
 421
 422                 public override bool HasClassConstraint {
 423                         get { return class_constraint != null; }
 424                 }
 425
 426                 public override Type ClassConstraint {
 427                         get { return class_constraint_type; }
 428                 }
 429
 430                 public override Type[] InterfaceConstraints {
 431                         get { return iface_constraint_types; }
 432                 }
 433
 434                 public override Type EffectiveBaseClass {
 435                         get { return effective_base_type; }
 436                 }
 437
 438                 internal bool IsSubclassOf (Type t)
 439                 {
 440                         if ((class_constraint_type != null) &&
 441                             class_constraint_type.IsSubclassOf (t))
 442                                 return true;
 443
 444                         if (iface_constraint_types == null)
 445                                 return false;
 446
 447                         foreach (Type iface in iface_constraint_types) {
 448                                 if (TypeManager.IsSubclassOf (iface, t))
 449                                         return true;
 450                         }
 451
 452                         return false;
 453                 }
 454
 455                 public bool CheckInterfaceMethod (EmitContext ec, GenericConstraints gc)
 456                 {
 457                         if (gc.Attributes != attrs)
 458                                 return false;
 459
 460                         if (HasClassConstraint != gc.HasClassConstraint)
 461                                 return false;
 462                         if (HasClassConstraint && !TypeManager.IsEqual (gc.ClassConstraint, ClassConstraint))
 463                                 return false;
 464
 465                         int gc_icount = gc.InterfaceConstraints != null ?
 466                                 gc.InterfaceConstraints.Length : 0;
 467                         int icount = InterfaceConstraints != null ?
 468                                 InterfaceConstraints.Length : 0;
 469
 470                         if (gc_icount != icount)
 471                                 return false;
 472
 473                         foreach (Type iface in gc.InterfaceConstraints) {
 474                                 bool ok = false;
 475                                 foreach (Type check in InterfaceConstraints) {
 476                                         if (TypeManager.IsEqual (iface, check)) {
 477                                                 ok = true;
 478                                                 break;
 479                                         }
 480                                 }
 481
 482                                 if (!ok)
 483                                         return false;
 484                         }
 485
 486                         return true;
 487                 }
 488         }
 489
 490         //
 491         // This type represents a generic type parameter
 492         //
 493         public class TypeParameter : MemberCore, IMemberContainer {
 494                 string name;
 495                 GenericConstraints gc;
 496                 Constraints constraints;
 497                 Location loc;
 498                 GenericTypeParameterBuilder type;
 499
 500                 public TypeParameter (TypeContainer parent, string name,
 501                                       Constraints constraints, Location loc)
 502                         : base (parent, new MemberName (name), null, loc)
 503                 {
 504                         this.name = name;
 505                         this.constraints = constraints;
 506                         this.loc = loc;
 507                 }
 508
 509                 public GenericConstraints GenericConstraints {
 510                         get {
 511                                 return gc != null ? gc : constraints;
 512                         }
 513                 }
 514
 515                 public Constraints Constraints {
 516                         get {
 517                                 return constraints;
 518                         }
 519                 }
 520
 521                 public bool HasConstructorConstraint {
 522                         get {
 523                                 if (constraints != null)
 524                                         return constraints.HasConstructorConstraint;
 525
 526                                 return false;
 527                         }
 528                 }
 529
 530                 public Type Type {
 531                         get {
 532                                 return type;
 533                         }
 534                 }
 535
 536                 public bool Resolve (DeclSpace ds)
 537                 {
 538                         if (constraints != null) {
 539                                 if (!constraints.Resolve (ds.EmitContext)) {
 540                                         constraints = null;
 541                                         return false;
 542                                 }
 543                         }
 544
 545                         return true;
 546                 }
 547
 548                 public void Define (GenericTypeParameterBuilder type)
 549                 {
 550                         if (this.type != null)
 551                                 throw new InvalidOperationException ();
 552
 553                         this.type = type;
 554                         TypeManager.AddTypeParameter (type, this);
 555                 }
 556
 557                 public void DefineConstraints ()
 558                 {
 559                         if (constraints != null)
 560                                 constraints.Define (type);
 561                 }
 562
 563                 public bool ResolveType (EmitContext ec)
 564                 {
 565                         if (constraints != null) {
 566                                 if (!constraints.ResolveTypes (ec)) {
 567                                         constraints = null;
 568                                         return false;
 569                                 }
 570                         }
 571
 572                         return true;
 573                 }
 574
 575                 public bool DefineType (EmitContext ec)
 576                 {
 577                         return DefineType (ec, null, null, false);
 578                 }
 579
 580                 public bool DefineType (EmitContext ec, MethodBuilder builder,
 581                                         MethodInfo implementing, bool is_override)
 582                 {
 583                         if (!ResolveType (ec))
 584                                 return false;
 585
 586                         if (implementing != null) {
 587                                 if (is_override && (constraints != null)) {
 588                                         Report.Error (
 589                                                 460, loc, "Constraints for override and " +
 590                                                 "explicit interface implementation methods " +
 591                                                 "are inherited from the base method so they " +
 592                                                 "cannot be specified directly");
 593                                         return false;
 594                                 }
 595
 596                                 MethodBase mb = implementing;
 597                                 if (mb.Mono_IsInflatedMethod)
 598                                         mb = mb.GetGenericMethodDefinition ();
 599
 600                                 int pos = type.GenericParameterPosition;
 601                                 ParameterData pd = Invocation.GetParameterData (mb);
 602                                 GenericConstraints temp_gc = pd.GenericConstraints (pos);
 603                                 Type mparam = mb.GetGenericArguments () [pos];
 604
 605                                 if (temp_gc != null)
 606                                         gc = new InflatedConstraints (temp_gc, implementing.DeclaringType);
 607                                 else if (constraints != null)
 608                                         gc = new InflatedConstraints (constraints, implementing.DeclaringType);
 609
 610                                 bool ok = true;
 611                                 if (constraints != null) {
 612                                         if (temp_gc == null)
 613                                                 ok = false;
 614                                         else if (!constraints.CheckInterfaceMethod (ec, gc))
 615                                                 ok = false;
 616                                 } else {
 617                                         if (!is_override && (temp_gc != null))
 618                                                 ok = false;
 619                                 }
 620
 621                                 if (!ok) {
 622                                         Report.SymbolRelatedToPreviousError (implementing);
 623
 624                                         Report.Error (
 625                                                 425, loc, "The constraints for type " +
 626                                                 "parameter `{0}' of method `{1}' must match " +
 627                                                 "the constraints for type parameter `{2}' " +
 628                                                 "of interface method `{3}'.  Consider using " +
 629                                                 "an explicit interface implementation instead",
 630                                                 Name, TypeManager.CSharpSignature (builder),
 631                                                 mparam, TypeManager.CSharpSignature (mb));
 632                                         return false;
 633                                 }
 634                         } else {
 635                                 gc = (GenericConstraints) constraints;
 636                         }
 637
 638                         if (gc == null)
 639                                 return true;
 640
 641                         if (gc.HasClassConstraint)
 642                                 type.SetBaseTypeConstraint (gc.ClassConstraint);
 643
 644                         type.SetInterfaceConstraints (gc.InterfaceConstraints);
 645                         TypeManager.RegisterBuilder (type, gc.InterfaceConstraints);
 646
 647                         return true;
 648                 }
 649
 650                 public bool CheckDependencies (EmitContext ec)
 651                 {
 652                         if (constraints != null)
 653                                 return constraints.CheckDependencies (ec);
 654
 655                         return true;
 656                 }
 657
 658                 public override string DocCommentHeader {
 659                         get {
 660                                 throw new InvalidOperationException (
 661                                         "Unexpected attempt to get doc comment from " + this.GetType () + ".");
 662                         }
 663                 }
 664
 665                 //
 666                 // MemberContainer
 667                 //
 668
 669                 public override bool Define ()
 670                 {
 671                         return true;
 672                 }
 673
 674                 protected override void VerifyObsoleteAttribute ()
 675                 { }
 676
 677                 public override void ApplyAttributeBuilder (Attribute a,
 678                                                             CustomAttributeBuilder cb)
 679                 { }
 680
 681                 public override AttributeTargets AttributeTargets {
 682                         get {
 683                                 return (AttributeTargets) 0;
 684                         }
 685                 }
 686
 687                 public override string[] ValidAttributeTargets {
 688                         get {
 689                                 return new string [0];
 690                         }
 691                 }
 692
 693                 //
 694                 // IMemberContainer
 695                 //
 696
 697                 string IMemberContainer.Name {
 698                         get { return Name; }
 699                 }
 700
 701                 MemberCache IMemberContainer.BaseCache {
 702                         get { return null; }
 703                 }
 704
 705                 bool IMemberContainer.IsInterface {
 706                         get { return true; }
 707                 }
 708
 709                 MemberList IMemberContainer.GetMembers (MemberTypes mt, BindingFlags bf)
 710                 {
 711                         return FindMembers (mt, bf, null, null);
 712                 }
 713
 714                 MemberCache IMemberContainer.MemberCache {
 715                         get { return null; }
 716                 }
 717
 718                 public MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 719                                                MemberFilter filter, object criteria)
 720                 {
 721                         if (constraints == null)
 722                                 return MemberList.Empty;
 723
 724                         ArrayList members = new ArrayList ();
 725
 726                         GenericConstraints gc = (GenericConstraints) constraints;
 727
 728                         if (gc.HasClassConstraint) {
 729                                 MemberList list = TypeManager.FindMembers (
 730                                         gc.ClassConstraint, mt, bf, filter, criteria);
 731
 732                                 members.AddRange (list);
 733                         }
 734
 735                         foreach (Type t in gc.InterfaceConstraints) {
 736                                 MemberList list = TypeManager.FindMembers (
 737                                         t, mt, bf, filter, criteria);
 738
 739                                 members.AddRange (list);
 740                         }
 741
 742                         return new MemberList (members);
 743                 }
 744
 745                 public bool IsSubclassOf (Type t)
 746                 {
 747                         if (type.Equals (t))
 748                                 return true;
 749
 750                         if (constraints != null)
 751                                 return constraints.IsSubclassOf (t);
 752
 753                         return false;
 754                 }
 755
 756                 public override string ToString ()
 757                 {
 758                         return "TypeParameter[" + name + "]";
 759                 }
 760
 761                 protected class InflatedConstraints : GenericConstraints
 762                 {
 763                         GenericConstraints gc;
 764                         Type base_type;
 765                         Type class_constraint;
 766                         Type[] iface_constraints;
 767                         Type[] dargs;
 768                         Type declaring;
 769
 770                         public InflatedConstraints (GenericConstraints gc, Type declaring)
 771                         {
 772                                 this.gc = gc;
 773                                 this.declaring = declaring;
 774
 775                                 dargs = TypeManager.GetTypeArguments (declaring);
 776
 777                                 ArrayList list = new ArrayList ();
 778                                 if (gc.HasClassConstraint)
 779                                         list.Add (inflate (gc.ClassConstraint));
 780                                 foreach (Type iface in gc.InterfaceConstraints)
 781                                         list.Add (inflate (iface));
 782
 783                                 bool has_class_constr = false;
 784                                 if (list.Count > 0) {
 785                                         Type first = (Type) list [0];
 786                                         has_class_constr = !first.IsInterface && !first.IsGenericParameter;
 787                                 }
 788
 789                                 if ((list.Count > 0) && has_class_constr) {
 790                                         class_constraint = (Type) list [0];
 791                                         iface_constraints = new Type [list.Count - 1];
 792                                         list.CopyTo (1, iface_constraints, 0, list.Count - 1);
 793                                 } else {
 794                                         iface_constraints = new Type [list.Count];
 795                                         list.CopyTo (iface_constraints, 0);
 796                                 }
 797
 798                                 if (HasValueTypeConstraint)
 799                                         base_type = TypeManager.value_type;
 800                                 else if (class_constraint != null)
 801                                         base_type = class_constraint;
 802                                 else
 803                                         base_type = TypeManager.object_type;
 804                         }
 805
 806                         Type inflate (Type t)
 807                         {
 808                                 if (t == null)
 809                                         return null;
 810                                 if (t.IsGenericParameter)
 811                                         return dargs [t.GenericParameterPosition];
 812                                 if (t.IsGenericInstance) {
 813                                         t = t.GetGenericTypeDefinition ();
 814                                         t = t.BindGenericParameters (dargs);
 815                                 }
 816
 817                                 return t;
 818                         }
 819
 820                         public override GenericParameterAttributes Attributes {
 821                                 get { return gc.Attributes; }
 822                         }
 823
 824                         public override Type ClassConstraint {
 825                                 get { return class_constraint; }
 826                         }
 827
 828                         public override Type EffectiveBaseClass {
 829                                 get { return base_type; }
 830                         }
 831
 832                         public override Type[] InterfaceConstraints {
 833                                 get { return iface_constraints; }
 834                         }
 835                 }
 836         }
 837
 838         //
 839         // This type represents a generic type parameter reference.
 840         //
 841         // These expressions are born in a fully resolved state.
 842         //
 843         public class TypeParameterExpr : TypeExpr {
 844                 TypeParameter type_parameter;
 845
 846                 public override string Name {
 847                         get {
 848                                 return type_parameter.Name;
 849                         }
 850                 }
 851
 852                 public override string FullName {
 853                         get {
 854                                 return type_parameter.Name;
 855                         }
 856                 }
 857
 858                 public TypeParameter TypeParameter {
 859                         get {
 860                                 return type_parameter;
 861                         }
 862                 }
 863
 864                 public TypeParameterExpr (TypeParameter type_parameter, Location loc)
 865                 {
 866                         this.type_parameter = type_parameter;
 867                         this.loc = loc;
 868                 }
 869
 870                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
 871                 {
 872                         type = type_parameter.Type;
 873
 874                         return this;
 875                 }
 876
 877                 public override bool IsInterface {
 878                         get { return false; }
 879                 }
 880
 881                 public override bool CheckAccessLevel (DeclSpace ds)
 882                 {
 883                         return true;
 884                 }
 885
 886                 public void Error_CannotUseAsUnmanagedType (Location loc)
 887                 {
 888                         Report.Error (-203, loc, "Can not use type parameter as unamanged type");
 889                 }
 890         }
 891
 892         public class TypeArguments {
 893                 public readonly Location Location;
 894                 ArrayList args;
 895                 Type[] atypes;
 896                 int dimension;
 897                 bool has_type_args;
 898                 bool created;
 899
 900                 public TypeArguments (Location loc)
 901                 {
 902                         args = new ArrayList ();
 903                         this.Location = loc;
 904                 }
 905
 906                 public TypeArguments (int dimension, Location loc)
 907                 {
 908                         this.dimension = dimension;
 909                         this.Location = loc;
 910                 }
 911
 912                 public void Add (Expression type)
 913                 {
 914                         if (created)
 915                                 throw new InvalidOperationException ();
 916
 917                         args.Add (type);
 918                 }
 919
 920                 public void Add (TypeArguments new_args)
 921                 {
 922                         if (created)
 923                                 throw new InvalidOperationException ();
 924
 925                         args.AddRange (new_args.args);
 926                 }
 927
 928                 public string[] GetDeclarations ()
 929                 {
 930                         string[] ret = new string [args.Count];
 931                         for (int i = 0; i < args.Count; i++) {
 932                                 SimpleName sn = args [i] as SimpleName;
 933                                 if (sn != null) {
 934                                         ret [i] = sn.Name;
 935                                         continue;
 936                                 }
 937
 938                                 Report.Error (81, Location, "Type parameter declaration " +
 939                                               "must be an identifier not a type");
 940                                 return null;
 941                         }
 942                         return ret;
 943                 }
 944
 945                 public Type[] Arguments {
 946                         get {
 947                                 return atypes;
 948                         }
 949                 }
 950
 951                 public bool HasTypeArguments {
 952                         get {
 953                                 return has_type_args;
 954                         }
 955                 }
 956
 957                 public int Count {
 958                         get {
 959                                 if (dimension > 0)
 960                                         return dimension;
 961                                 else
 962                                         return args.Count;
 963                         }
 964                 }
 965
 966                 public bool IsUnbound {
 967                         get {
 968                                 return dimension > 0;
 969                         }
 970                 }
 971
 972                 public override string ToString ()
 973                 {
 974                         StringBuilder s = new StringBuilder ();
 975
 976                         int count = Count;
 977                         for (int i = 0; i < count; i++){
 978                                 //
 979                                 // FIXME: Use TypeManager.CSharpname once we have the type
 980                                 //
 981                                 if (args != null)
 982                                         s.Append (args [i].ToString ());
 983                                 if (i+1 < count)
 984                                         s.Append (",");
 985                         }
 986                         return s.ToString ();
 987                 }
 988
 989                 public bool Resolve (EmitContext ec)
 990                 {
 991                         int count = args.Count;
 992                         bool ok = true;
 993
 994                         atypes = new Type [count];
 995
 996                         for (int i = 0; i < count; i++){
 997                                 TypeExpr te = ((Expression) args [i]).ResolveAsTypeTerminal (ec);
 998                                 if (te == null) {
 999                                         ok = false;
1000                                         continue;
1001                                 }
1002                                 if (te is TypeParameterExpr)
1003                                         has_type_args = true;
1004
1005                                 atypes [i] = te.Type;
1006                         }
1007                         return ok;
1008                 }
1009         }
1010
1011         public class ConstructedType : TypeExpr {
1012                 string name, full_name;
1013                 TypeArguments args;
1014                 Type[] gen_params, atypes;
1015                 Type gt;
1016
1017                 public ConstructedType (string name, TypeArguments args, Location l)
1018                 {
1019                         loc = l;
1020                         this.name = MemberName.MakeName (name, args.Count);
1021                         this.args = args;
1022
1023                         eclass = ExprClass.Type;
1024                         full_name = name + "<" + args.ToString () + ">";
1025                 }
1026
1027                 public ConstructedType (string name, TypeParameter[] type_params, Location l)
1028                         : this (type_params, l)
1029                 {
1030                         loc = l;
1031
1032                         this.name = name;
1033                         full_name = name + "<" + args.ToString () + ">";
1034                 }
1035
1036                 public ConstructedType (FullNamedExpression fname, TypeArguments args, Location l)
1037                 {
1038                         loc = l;
1039                         this.name = fname.FullName;
1040                         this.args = args;
1041
1042                         eclass = ExprClass.Type;
1043                         full_name = name + "<" + args.ToString () + ">";
1044                 }
1045
1046                 protected ConstructedType (TypeArguments args, Location l)
1047                 {
1048                         loc = l;
1049                         this.args = args;
1050
1051                         eclass = ExprClass.Type;
1052                 }
1053
1054                 protected ConstructedType (TypeParameter[] type_params, Location l)
1055                 {
1056                         loc = l;
1057
1058                         args = new TypeArguments (l);
1059                         foreach (TypeParameter type_param in type_params)
1060                                 args.Add (new TypeParameterExpr (type_param, l));
1061
1062                         eclass = ExprClass.Type;
1063                 }
1064
1065                 public ConstructedType (Type t, TypeParameter[] type_params, Location l)
1066                         : this (type_params, l)
1067                 {
1068                         gt = t.GetGenericTypeDefinition ();
1069
1070                         this.name = gt.FullName;
1071                         full_name = gt.FullName + "<" + args.ToString () + ">";
1072                 }
1073
1074                 public ConstructedType (Type t, TypeArguments args, Location l)
1075                         : this (args, l)
1076                 {
1077                         gt = t.GetGenericTypeDefinition ();
1078
1079                         this.name = gt.FullName;
1080                         full_name = gt.FullName + "<" + args.ToString () + ">";
1081                 }
1082
1083                 public TypeArguments TypeArguments {
1084                         get { return args; }
1085                 }
1086
1087                 protected string DeclarationName {
1088                         get {
1089                                 StringBuilder sb = new StringBuilder ();
1090                                 sb.Append (gt.FullName);
1091                                 sb.Append ("<");
1092                                 for (int i = 0; i < gen_params.Length; i++) {
1093                                         if (i > 0)
1094                                                 sb.Append (",");
1095                                         sb.Append (gen_params [i]);
1096                                 }
1097                                 sb.Append (">");
1098                                 return sb.ToString ();
1099                         }
1100                 }
1101
1102                 protected bool CheckConstraint (EmitContext ec, Type ptype, Expression expr,
1103                                                 Type ctype)
1104                 {
1105                         if (TypeManager.HasGenericArguments (ctype)) {
1106                                 Type[] types = TypeManager.GetTypeArguments (ctype);
1107
1108                                 TypeArguments new_args = new TypeArguments (loc);
1109
1110                                 for (int i = 0; i < types.Length; i++) {
1111                                         Type t = types [i];
1112
1113                                         if (t.IsGenericParameter) {
1114                                                 int pos = t.GenericParameterPosition;
1115                                                 t = args.Arguments [pos];
1116                                         }
1117                                         new_args.Add (new TypeExpression (t, loc));
1118                                 }
1119
1120                                 TypeExpr ct = new ConstructedType (ctype, new_args, loc);
1121                                 if (ct.ResolveAsTypeTerminal (ec) == null)
1122                                         return false;
1123                                 ctype = ct.Type;
1124                         }
1125
1126                         return Convert.ImplicitStandardConversionExists (ec, expr, ctype);
1127                 }
1128
1129                 protected bool CheckConstraints (EmitContext ec, int index)
1130                 {
1131                         Type atype = atypes [index];
1132                         Type ptype = gen_params [index];
1133
1134                         if (atype == ptype)
1135                                 return true;
1136
1137                         Expression aexpr = new EmptyExpression (atype);
1138
1139                         GenericConstraints gc = TypeManager.GetTypeParameterConstraints (ptype);
1140                         if (gc == null)
1141                                 return true;
1142
1143                         bool is_class, is_struct;
1144                         if (atype.IsGenericParameter) {
1145                                 GenericConstraints agc = TypeManager.GetTypeParameterConstraints (atype);
1146                                 if (agc != null) {
1147                                         is_class = agc.HasReferenceTypeConstraint;
1148                                         is_struct = agc.HasValueTypeConstraint;
1149                                 } else {
1150                                         is_class = is_struct = false;
1151                                 }
1152                         } else {
1153                                 is_class = atype.IsClass;
1154                                 is_struct = atype.IsValueType;
1155                         }
1156
1157                         //
1158                         // First, check the `class' and `struct' constraints.
1159                         //
1160                         if (gc.HasReferenceTypeConstraint && !is_class) {
1161                                 Report.Error (452, loc, "The type `{0}' must be " +
1162                                               "a reference type in order to use it " +
1163                                               "as type parameter `{1}' in the " +
1164                                               "generic type or method `{2}'.",
1165                                               atype, ptype, DeclarationName);
1166                                 return false;
1167                         } else if (gc.HasValueTypeConstraint && !is_struct) {
1168                                 Report.Error (453, loc, "The type `{0}' must be " +
1169                                               "a value type in order to use it " +
1170                                               "as type parameter `{1}' in the " +
1171                                               "generic type or method `{2}'.",
1172                                               atype, ptype, DeclarationName);
1173                                 return false;
1174                         }
1175
1176                         //
1177                         // The class constraint comes next.
1178                         //
1179                         if (gc.HasClassConstraint) {
1180                                 if (!CheckConstraint (ec, ptype, aexpr, gc.ClassConstraint)) {
1181                                         Report.Error (309, loc, "The type `{0}' must be " +
1182                                                       "convertible to `{1}' in order to " +
1183                                                       "use it as parameter `{2}' in the " +
1184                                                       "generic type or method `{3}'",
1185                                                       atype, gc.ClassConstraint, ptype, DeclarationName);
1186                                         return false;
1187                                 }
1188                         }
1189
1190                         //
1191                         // Now, check the interface constraints.
1192                         //
1193                         foreach (Type it in gc.InterfaceConstraints) {
1194                                 Type itype;
1195                                 if (it.IsGenericParameter)
1196                                         itype = atypes [it.GenericParameterPosition];
1197                                 else
1198                                         itype = it;
1199
1200                                 if (!CheckConstraint (ec, ptype, aexpr, itype)) {
1201                                         Report.Error (309, loc, "The type `{0}' must be " +
1202                                                       "convertible to `{1}' in order to " +
1203                                                       "use it as parameter `{2}' in the " +
1204                                                       "generic type or method `{3}'",
1205                                                       atype, itype, ptype, DeclarationName);
1206                                         return false;
1207                                 }
1208                         }
1209
1210                         //
1211                         // Finally, check the constructor constraint.
1212                         //
1213
1214                         if (!gc.HasConstructorConstraint)
1215                                 return true;
1216
1217                         if (TypeManager.IsBuiltinType (atype) || atype.IsValueType)
1218                                 return true;
1219
1220                         MethodGroupExpr mg = Expression.MemberLookup (
1221                                 ec, atype, ".ctor", MemberTypes.Constructor,
1222                                 BindingFlags.Public | BindingFlags.Instance |
1223                                 BindingFlags.DeclaredOnly, loc)
1224                                 as MethodGroupExpr;
1225
1226                         if (atype.IsAbstract || (mg == null) || !mg.IsInstance) {
1227                                 Report.Error (310, loc, "The type `{0}' must have a public " +
1228                                               "parameterless constructor in order to use it " +
1229                                               "as parameter `{1}' in the generic type or " +
1230                                               "method `{2}'", atype, ptype, DeclarationName);
1231                                 return false;
1232                         }
1233
1234                         return true;
1235                 }
1236
1237                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
1238                 {
1239                         if (!ResolveConstructedType (ec))
1240                                 return null;
1241
1242                         return this;
1243                 }
1244
1245                 public bool CheckConstraints (EmitContext ec)
1246                 {
1247                         for (int i = 0; i < gen_params.Length; i++) {
1248                                 if (!CheckConstraints (ec, i))
1249                                         return false;
1250                         }
1251
1252                         return true;
1253                 }
1254
1255                 public override TypeExpr ResolveAsTypeTerminal (EmitContext ec)
1256                 {
1257                         if (base.ResolveAsTypeTerminal (ec) == null)
1258                                 return null;
1259
1260                         if (!CheckConstraints (ec))
1261                                 return null;
1262
1263                         return this;
1264                 }
1265
1266                 public bool ResolveConstructedType (EmitContext ec)
1267                 {
1268                         if (type != null)
1269                                 return true;
1270                         if (gt != null)
1271                                 return DoResolveType (ec);
1272
1273                         //
1274                         // First, resolve the generic type.
1275                         //
1276                         DeclSpace ds;
1277                         Type nested = ec.DeclSpace.FindNestedType (loc, name, out ds);
1278                         if (nested != null) {
1279                                 gt = nested.GetGenericTypeDefinition ();
1280
1281                                 TypeArguments new_args = new TypeArguments (loc);
1282                                 if (ds.IsGeneric) {
1283                                         foreach (TypeParameter param in ds.TypeParameters)
1284                                                 new_args.Add (new TypeParameterExpr (param, loc));
1285                                 }
1286                                 new_args.Add (args);
1287
1288                                 args = new_args;
1289                                 return DoResolveType (ec);
1290                         }
1291
1292                         Type t;
1293                         int num_args;
1294
1295                         SimpleName sn = new SimpleName (name, loc);
1296                         TypeExpr resolved = sn.ResolveAsTypeTerminal (ec);
1297                         if (resolved == null)
1298                                 return false;
1299
1300                         t = resolved.Type;
1301                         if (t == null) {
1302                                 Report.Error (246, loc, "Cannot find type `{0}'<...>",
1303                                               Basename);
1304                                 return false;
1305                         }
1306
1307                         num_args = TypeManager.GetNumberOfTypeArguments (t);
1308                         if (num_args == 0) {
1309                                 Report.Error (308, loc,
1310                                               "The non-generic type `{0}' cannot " +
1311                                               "be used with type arguments.",
1312                                               TypeManager.CSharpName (t));
1313                                 return false;
1314                         }
1315
1316                         gt = t.GetGenericTypeDefinition ();
1317                         return DoResolveType (ec);
1318                 }
1319
1320                 bool DoResolveType (EmitContext ec)
1321                 {
1322                         //
1323                         // Resolve the arguments.
1324                         //
1325                         if (args.Resolve (ec) == false)
1326                                 return false;
1327
1328                         gen_params = gt.GetGenericArguments ();
1329                         atypes = args.Arguments;
1330
1331                         if (atypes.Length != gen_params.Length) {
1332                                 Report.Error (305, loc,
1333                                               "Using the generic type `{0}' " +
1334                                               "requires {1} type arguments",
1335                                               TypeManager.GetFullName (gt),
1336                                               gen_params.Length);
1337                                 return false;
1338                         }
1339
1340                         //
1341                         // Now bind the parameters.
1342                         //
1343                         type = gt.BindGenericParameters (atypes);
1344                         return true;
1345                 }
1346
1347                 public Expression GetSimpleName (EmitContext ec)
1348                 {
1349                         return new SimpleName (Basename, args, loc);
1350                 }
1351
1352                 public override bool CheckAccessLevel (DeclSpace ds)
1353                 {
1354                         return ds.CheckAccessLevel (gt);
1355                 }
1356
1357                 public override bool AsAccessible (DeclSpace ds, int flags)
1358                 {
1359                         return ds.AsAccessible (gt, flags);
1360                 }
1361
1362                 public override bool IsClass {
1363                         get { return gt.IsClass; }
1364                 }
1365
1366                 public override bool IsValueType {
1367                         get { return gt.IsValueType; }
1368                 }
1369
1370                 public override bool IsInterface {
1371                         get { return gt.IsInterface; }
1372                 }
1373
1374                 public override bool IsSealed {
1375                         get { return gt.IsSealed; }
1376                 }
1377
1378                 public override bool IsAttribute {
1379                         get { return false; }
1380                 }
1381
1382                 public override bool Equals (object obj)
1383                 {
1384                         ConstructedType cobj = obj as ConstructedType;
1385                         if (cobj == null)
1386                                 return false;
1387
1388                         if ((type == null) || (cobj.type == null))
1389                                 return false;
1390
1391                         return type == cobj.type;
1392                 }
1393
1394                 public override int GetHashCode ()
1395                 {
1396                         return base.GetHashCode ();
1397                 }
1398
1399                 public string Basename {
1400                         get {
1401                                 int pos = name.LastIndexOf ('`');
1402                                 if (pos >= 0)
1403                                         return name.Substring (0, pos);
1404                                 else
1405                                         return name;
1406                         }
1407                 }
1408
1409                 public override string Name {
1410                         get {
1411                                 return full_name;
1412                         }
1413                 }
1414
1415
1416                 public override string FullName {
1417                         get {
1418                                 return full_name;
1419                         }
1420                 }
1421         }
1422
1423         public class GenericMethod : DeclSpace
1424         {
1425                 public GenericMethod (NamespaceEntry ns, TypeContainer parent,
1426                                       MemberName name, Location l)
1427                         : base (ns, parent, name, null, l)
1428                 { }
1429
1430                 public override TypeBuilder DefineType ()
1431                 {
1432                         throw new Exception ();
1433                 }
1434
1435                 public override bool Define ()
1436                 {
1437                         for (int i = 0; i < TypeParameters.Length; i++)
1438                                 if (!TypeParameters [i].Resolve (Parent))
1439                                         return false;
1440
1441                         return true;
1442                 }
1443
1444                 public bool Define (MethodBuilder mb, Type return_type)
1445                 {
1446                         if (!Define ())
1447                                 return false;
1448
1449                         GenericTypeParameterBuilder[] gen_params;
1450                         string[] names = MemberName.TypeArguments.GetDeclarations ();
1451                         gen_params = mb.DefineGenericParameters (names);
1452                         for (int i = 0; i < TypeParameters.Length; i++)
1453                                 TypeParameters [i].Define (gen_params [i]);
1454
1455                         ec = new EmitContext (
1456                                 this, this, Location, null, return_type, ModFlags, false);
1457
1458                         for (int i = 0; i < TypeParameters.Length; i++) {
1459                                 if (!TypeParameters [i].ResolveType (ec))
1460                                         return false;
1461                         }
1462
1463                         return true;
1464                 }
1465
1466                 public bool DefineType (EmitContext ec, MethodBuilder mb,
1467                                         MethodInfo implementing, bool is_override)
1468                 {
1469                         for (int i = 0; i < TypeParameters.Length; i++)
1470                                 if (!TypeParameters [i].DefineType (
1471                                             ec, mb, implementing, is_override))
1472                                         return false;
1473
1474                         return true;
1475                 }
1476
1477                 public override bool DefineMembers (TypeContainer parent)
1478                 {
1479                         return true;
1480                 }
1481
1482                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
1483                                                         MemberFilter filter, object criteria)
1484                 {
1485                         throw new Exception ();
1486                 }
1487
1488                 public override MemberCache MemberCache {
1489                         get {
1490                                 return null;
1491                         }
1492                 }
1493
1494                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
1495                 {
1496                         // FIXME
1497                 }
1498
1499                 protected override void VerifyObsoleteAttribute()
1500                 {
1501                         // FIXME
1502                 }
1503
1504                 public override AttributeTargets AttributeTargets {
1505                         get {
1506                                 return AttributeTargets.Method | AttributeTargets.ReturnValue;
1507                         }
1508                 }
1509
1510                 public override string DocCommentHeader {
1511                         get { return "M:"; }
1512                 }
1513         }
1514
1515         public class DefaultValueExpression : Expression
1516         {
1517                 Expression expr;
1518                 LocalTemporary temp_storage;
1519
1520                 public DefaultValueExpression (Expression expr, Location loc)
1521                 {
1522                         this.expr = expr;
1523                         this.loc = loc;
1524                 }
1525
1526                 public override Expression DoResolve (EmitContext ec)
1527                 {
1528                         TypeExpr texpr = expr.ResolveAsTypeTerminal (ec);
1529                         if (texpr == null)
1530                                 return null;
1531
1532                         type = texpr.Type;
1533                         if (type.IsGenericParameter || TypeManager.IsValueType (type))
1534                                 temp_storage = new LocalTemporary (ec, type);
1535
1536                         eclass = ExprClass.Variable;
1537                         return this;
1538                 }
1539
1540                 public override void Emit (EmitContext ec)
1541                 {
1542                         if (temp_storage != null) {
1543                                 temp_storage.AddressOf (ec, AddressOp.LoadStore);
1544                                 ec.ig.Emit (OpCodes.Initobj, type);
1545                                 temp_storage.Emit (ec);
1546                         } else
1547                                 ec.ig.Emit (OpCodes.Ldnull);
1548                 }
1549         }
1550
1551         public partial class TypeManager
1552         {
1553                 //
1554                 // A list of core types that the compiler requires or uses
1555                 //
1556                 static public Type new_constraint_attr_type;
1557                 static public Type activator_type;
1558                 static public Type generic_ienumerator_type;
1559                 static public Type generic_ienumerable_type;
1560                 static public Type generic_nullable_type;
1561
1562                 // <remarks>
1563                 //   Tracks the generic parameters.
1564                 // </remarks>
1565                 static PtrHashtable builder_to_type_param;
1566
1567                 //
1568                 // These methods are called by code generated by the compiler
1569                 //
1570                 static public MethodInfo activator_create_instance;
1571
1572                 static void InitGenerics ()
1573                 {
1574                         builder_to_type_param = new PtrHashtable ();
1575                 }
1576
1577                 static void CleanUpGenerics ()
1578                 {
1579                         builder_to_type_param = null;
1580                 }
1581
1582                 static void InitGenericCoreTypes ()
1583                 {
1584                         activator_type = CoreLookupType ("System.Activator");
1585                         new_constraint_attr_type = CoreLookupType (
1586                                 "System.Runtime.CompilerServices.NewConstraintAttribute");
1587
1588                         generic_ienumerator_type = CoreLookupType ("System.Collections.Generic.IEnumerator", 1);
1589                         generic_ienumerable_type = CoreLookupType ("System.Collections.Generic.IEnumerable", 1);
1590                         generic_nullable_type = CoreLookupType ("System.Nullable", 1);
1591                 }
1592
1593                 static void InitGenericCodeHelpers ()
1594                 {
1595                         // Activator
1596                         Type [] type_arg = { type_type };
1597                         activator_create_instance = GetMethod (
1598                                 activator_type, "CreateInstance", type_arg);
1599                 }
1600
1601                 static Type CoreLookupType (string name, int arity)
1602                 {
1603                         return CoreLookupType (MemberName.MakeName (name, arity));
1604                 }
1605
1606                 public static void AddTypeParameter (Type t, TypeParameter tparam)
1607                 {
1608                         if (!builder_to_type_param.Contains (t))
1609                                 builder_to_type_param.Add (t, tparam);
1610                 }
1611
1612                 public static TypeContainer LookupGenericTypeContainer (Type t)
1613                 {
1614                         while (t.IsGenericInstance)
1615                                 t = t.GetGenericTypeDefinition ();
1616
1617                         return LookupTypeContainer (t);
1618                 }
1619
1620                 public static TypeParameter LookupTypeParameter (Type t)
1621                 {
1622                         return (TypeParameter) builder_to_type_param [t];
1623                 }
1624
1625                 public static bool HasConstructorConstraint (Type t)
1626                 {
1627                         GenericConstraints gc = GetTypeParameterConstraints (t);
1628                         if (gc == null)
1629                                 return false;
1630
1631                         return (gc.Attributes & GenericParameterAttributes.DefaultConstructorConstraint) != 0;
1632                 }
1633
1634                 public static GenericConstraints GetTypeParameterConstraints (Type t)
1635                 {
1636                         if (!t.IsGenericParameter)
1637                                 throw new InvalidOperationException ();
1638
1639                         TypeParameter tparam = LookupTypeParameter (t);
1640                         if (tparam != null)
1641                                 return tparam.GenericConstraints;
1642
1643                         return new ReflectionConstraints (t);
1644                 }
1645
1646                 public static bool IsGeneric (Type t)
1647                 {
1648                         DeclSpace ds = (DeclSpace) builder_to_declspace [t];
1649
1650                         return ds.IsGeneric;
1651                 }
1652
1653                 public static bool HasGenericArguments (Type t)
1654                 {
1655                         return GetNumberOfTypeArguments (t) > 0;
1656                 }
1657
1658                 public static int GetNumberOfTypeArguments (Type t)
1659                 {
1660                         DeclSpace tc = LookupDeclSpace (t);
1661                         if (tc != null)
1662                                 return tc.IsGeneric ? tc.CountTypeParameters : 0;
1663                         else
1664                                 return t.HasGenericArguments ? t.GetGenericArguments ().Length : 0;
1665                 }
1666
1667                 public static Type[] GetTypeArguments (Type t)
1668                 {
1669                         DeclSpace tc = LookupDeclSpace (t);
1670                         if (tc != null) {
1671                                 if (!tc.IsGeneric)
1672                                         return Type.EmptyTypes;
1673
1674                                 TypeParameter[] tparam = tc.TypeParameters;
1675                                 Type[] ret = new Type [tparam.Length];
1676                                 for (int i = 0; i < tparam.Length; i++) {
1677                                         ret [i] = tparam [i].Type;
1678                                         if (ret [i] == null)
1679                                                 throw new InternalErrorException ();
1680                                 }
1681
1682                                 return ret;
1683                         } else
1684                                 return t.GetGenericArguments ();
1685                 }
1686
1687                 public static bool IsEqual (Type a, Type b)
1688                 {
1689                         if (a.Equals (b))
1690                                 return true;
1691
1692                         if ((a is TypeBuilder) && a.IsGenericTypeDefinition && b.IsGenericInstance) {
1693                                 //
1694                                 // `a' is a generic type definition's TypeBuilder and `b' is a
1695                                 // generic instance of the same type.
1696                                 //
1697                                 // Example:
1698                                 //
1699                                 // class Stack<T>
1700                                 // {
1701                                 //     void Test (Stack<T> stack) { }
1702                                 // }
1703                                 //
1704                                 // The first argument of `Test' will be the generic instance
1705                                 // "Stack<!0>" - which is the same type than the "Stack" TypeBuilder.
1706                                 //
1707                                 //
1708                                 // We hit this via Closure.Filter() for gen-82.cs.
1709                                 //
1710                                 if (a != b.GetGenericTypeDefinition ())
1711                                         return false;
1712
1713                                 Type[] aparams = a.GetGenericArguments ();
1714                                 Type[] bparams = b.GetGenericArguments ();
1715
1716                                 if (aparams.Length != bparams.Length)
1717                                         return false;
1718
1719                                 for (int i = 0; i < aparams.Length; i++)
1720                                         if (!IsEqual (aparams [i], bparams [i]))
1721                                                 return false;
1722
1723                                 return true;
1724                         }
1725
1726                         if (a.IsGenericParameter && b.IsGenericParameter) {
1727                                 if ((a.DeclaringMethod == null) || (b.DeclaringMethod == null))
1728                                         return false;
1729                                 return a.GenericParameterPosition == b.GenericParameterPosition;
1730                         }
1731
1732                         if (a.IsArray && b.IsArray) {
1733                                 if (a.GetArrayRank () != b.GetArrayRank ())
1734                                         return false;
1735                                 return IsEqual (a.GetElementType (), b.GetElementType ());
1736                         }
1737
1738                         if (a.IsGenericInstance && b.IsGenericInstance) {
1739                                 if (a.GetGenericTypeDefinition () != b.GetGenericTypeDefinition ())
1740                                         return false;
1741
1742                                 Type[] aargs = a.GetGenericArguments ();
1743                                 Type[] bargs = b.GetGenericArguments ();
1744
1745                                 if (aargs.Length != bargs.Length)
1746                                         return false;
1747
1748                                 for (int i = 0; i < aargs.Length; i++) {
1749                                         if (!IsEqual (aargs [i], bargs [i]))
1750                                                 return false;
1751                                 }
1752
1753                                 return true;
1754                         }
1755
1756                         return false;
1757                 }
1758
1759                 public static bool MayBecomeEqualGenericTypes (Type a, Type b, Type[] class_infered, Type[] method_infered)
1760                 {
1761                         if (a.IsGenericParameter) {
1762                                 //
1763                                 // If a is an array of a's type, they may never
1764                                 // become equal.
1765                                 //
1766                                 while (b.IsArray) {
1767                                         b = b.GetElementType ();
1768                                         if (a.Equals (b))
1769                                                 return false;
1770                                 }
1771
1772                                 //
1773                                 // If b is a generic parameter or an actual type,
1774                                 // they may become equal:
1775                                 //
1776                                 //    class X<T,U> : I<T>, I<U>
1777                                 //    class X<T> : I<T>, I<float>
1778                                 //
1779                                 if (b.IsGenericParameter || !b.IsGenericInstance) {
1780                                         int pos = a.GenericParameterPosition;
1781                                         Type[] args = a.DeclaringMethod != null ? method_infered : class_infered;
1782                                         if (args [pos] == null) {
1783                                                 args [pos] = b;
1784                                                 return true;
1785                                         }
1786
1787                                         return args [pos] == a;
1788                                 }
1789
1790                                 //
1791                                 // We're now comparing a type parameter with a
1792                                 // generic instance.  They may become equal unless
1793                                 // the type parameter appears anywhere in the
1794                                 // generic instance:
1795                                 //
1796                                 //    class X<T,U> : I<T>, I<X<U>>
1797                                 //        -> error because you could instanciate it as
1798                                 //           X<X<int>,int>
1799                                 //
1800                                 //    class X<T> : I<T>, I<X<T>> -> ok
1801                                 //
1802
1803                                 Type[] bargs = GetTypeArguments (b);
1804                                 for (int i = 0; i < bargs.Length; i++) {
1805                                         if (a.Equals (bargs [i]))
1806                                                 return false;
1807                                 }
1808
1809                                 return true;
1810                         }
1811
1812                         if (b.IsGenericParameter)
1813                                 return MayBecomeEqualGenericTypes (b, a, class_infered, method_infered);
1814
1815                         //
1816                         // At this point, neither a nor b are a type parameter.
1817                         //
1818                         // If one of them is a generic instance, let
1819                         // MayBecomeEqualGenericInstances() compare them (if the
1820                         // other one is not a generic instance, they can never
1821                         // become equal).
1822                         //
1823
1824                         if (a.IsGenericInstance || b.IsGenericInstance)
1825                                 return MayBecomeEqualGenericInstances (a, b, class_infered, method_infered);
1826
1827                         //
1828                         // If both of them are arrays.
1829                         //
1830
1831                         if (a.IsArray && b.IsArray) {
1832                                 if (a.GetArrayRank () != b.GetArrayRank ())
1833                                         return false;
1834
1835                                 a = a.GetElementType ();
1836                                 b = b.GetElementType ();
1837
1838                                 return MayBecomeEqualGenericTypes (a, b, class_infered, method_infered);
1839                         }
1840
1841                         //
1842                         // Ok, two ordinary types.
1843                         //
1844
1845                         return a.Equals (b);
1846                 }
1847
1848                 //
1849                 // Checks whether two generic instances may become equal for some
1850                 // particular instantiation (26.3.1).
1851                 //
1852                 public static bool MayBecomeEqualGenericInstances (Type a, Type b,
1853                                                                    Type[] class_infered, Type[] method_infered)
1854                 {
1855                         if (!a.IsGenericInstance || !b.IsGenericInstance)
1856                                 return false;
1857                         if (a.GetGenericTypeDefinition () != b.GetGenericTypeDefinition ())
1858                                 return false;
1859
1860                         return MayBecomeEqualGenericInstances (
1861                                 GetTypeArguments (a), GetTypeArguments (b), class_infered, method_infered);
1862                 }
1863
1864                 public static bool MayBecomeEqualGenericInstances (Type[] aargs, Type[] bargs,
1865                                                                    Type[] class_infered, Type[] method_infered)
1866                 {
1867                         if (aargs.Length != bargs.Length)
1868                                 return false;
1869
1870                         for (int i = 0; i < aargs.Length; i++) {
1871                                 if (!MayBecomeEqualGenericTypes (aargs [i], bargs [i], class_infered, method_infered))
1872                                         return false;
1873                         }
1874
1875                         return true;
1876                 }
1877
1878                 public static bool IsEqualGenericInstance (Type type, Type parent)
1879                 {
1880                         int tcount = GetNumberOfTypeArguments (type);
1881                         int pcount = GetNumberOfTypeArguments (parent);
1882
1883                         if (type.IsGenericInstance)
1884                                 type = type.GetGenericTypeDefinition ();
1885                         if (parent.IsGenericInstance)
1886                                 parent = parent.GetGenericTypeDefinition ();
1887
1888                         if (tcount != pcount)
1889                                 return false;
1890
1891                         return type.Equals (parent);
1892                 }
1893
1894                 static public bool IsGenericMethod (MethodBase mb)
1895                 {
1896                         if (mb.DeclaringType is TypeBuilder) {
1897                                 IMethodData method = (IMethodData) builder_to_method [mb];
1898                                 if (method == null)
1899                                         return false;
1900
1901                                 return method.GenericMethod != null;
1902                         }
1903
1904                         return mb.IsGenericMethodDefinition;
1905                 }
1906
1907                 //
1908                 // Type inference.
1909                 //
1910
1911                 static bool InferType (Type pt, Type at, Type[] infered)
1912                 {
1913                         if (pt.IsGenericParameter && (pt.DeclaringMethod != null)) {
1914                                 int pos = pt.GenericParameterPosition;
1915
1916                                 if (infered [pos] == null) {
1917                                         Type check = at;
1918                                         while (check.IsArray)
1919                                                 check = check.GetElementType ();
1920
1921                                         if (pt == check)
1922                                                 return false;
1923
1924                                         infered [pos] = at;
1925                                         return true;
1926                                 }
1927
1928                                 if (infered [pos] != at)
1929                                         return false;
1930
1931                                 return true;
1932                         }
1933
1934                         if (!pt.ContainsGenericParameters) {
1935                                 if (at.ContainsGenericParameters)
1936                                         return InferType (at, pt, infered);
1937                                 else
1938                                         return true;
1939                         }
1940
1941                         if (at.IsArray) {
1942                                 if (!pt.IsArray ||
1943                                     (at.GetArrayRank () != pt.GetArrayRank ()))
1944                                         return false;
1945
1946                                 return InferType (pt.GetElementType (), at.GetElementType (), infered);
1947                         }
1948
1949                         if (pt.IsArray) {
1950                                 if (!at.IsArray ||
1951                                     (pt.GetArrayRank () != at.GetArrayRank ()))
1952                                         return false;
1953
1954                                 return InferType (pt.GetElementType (), at.GetElementType (), infered);
1955                         }
1956
1957                         if (pt.IsByRef && at.IsByRef)
1958                                 return InferType (pt.GetElementType (), at.GetElementType (), infered);
1959                         ArrayList list = new ArrayList ();
1960                         if (at.IsGenericInstance)
1961                                 list.Add (at);
1962                         else {
1963                                 for (Type bt = at.BaseType; bt != null; bt = bt.BaseType)
1964                                         list.Add (bt);
1965
1966                                 list.AddRange (TypeManager.GetInterfaces (at));
1967                         }
1968
1969                         bool found_one = false;
1970
1971                         foreach (Type type in list) {
1972                                 if (!type.IsGenericInstance)
1973                                         continue;
1974
1975                                 Type[] infered_types = new Type [infered.Length];
1976
1977                                 if (!InferGenericInstance (pt, type, infered_types))
1978                                         continue;
1979
1980                                 for (int i = 0; i < infered_types.Length; i++) {
1981                                         if (infered [i] == null) {
1982                                                 infered [i] = infered_types [i];
1983                                                 continue;
1984                                         }
1985
1986                                         if (infered [i] != infered_types [i])
1987                                                 return false;
1988                                 }
1989
1990                                 found_one = true;
1991                         }
1992
1993                         return found_one;
1994                 }
1995
1996                 static bool InferGenericInstance (Type pt, Type at, Type[] infered_types)
1997                 {
1998                         Type[] at_args = at.GetGenericArguments ();
1999                         Type[] pt_args = pt.GetGenericArguments ();
2000
2001                         if (at_args.Length != pt_args.Length)
2002                                 return false;
2003
2004                         for (int i = 0; i < at_args.Length; i++) {
2005                                 if (!InferType (pt_args [i], at_args [i], infered_types))
2006                                         return false;
2007                         }
2008
2009                         for (int i = 0; i < infered_types.Length; i++) {
2010                                 if (infered_types [i] == null)
2011                                         return false;
2012                         }
2013
2014                         return true;
2015                 }
2016
2017                 public static bool InferParamsTypeArguments (EmitContext ec, ArrayList arguments,
2018                                                              ref MethodBase method)
2019                 {
2020                         if ((arguments == null) || !TypeManager.IsGenericMethod (method))
2021                                 return true;
2022
2023                         int arg_count;
2024
2025                         if (arguments == null)
2026                                 arg_count = 0;
2027                         else
2028                                 arg_count = arguments.Count;
2029
2030                         ParameterData pd = Invocation.GetParameterData (method);
2031
2032                         int pd_count = pd.Count;
2033
2034                         if (pd_count == 0)
2035                                 return false;
2036
2037                         if (pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS)
2038                                 return false;
2039
2040                         if (pd_count - 1 > arg_count)
2041                                 return false;
2042
2043                         if (pd_count == 1 && arg_count == 0)
2044                                 return true;
2045
2046                         Type[] method_args = method.GetGenericArguments ();
2047                         Type[] infered_types = new Type [method_args.Length];
2048
2049                         //
2050                         // If we have come this far, the case which
2051                         // remains is when the number of parameters is
2052                         // less than or equal to the argument count.
2053                         //
2054                         for (int i = 0; i < pd_count - 1; ++i) {
2055                                 Argument a = (Argument) arguments [i];
2056
2057                                 if ((a.Expr is NullLiteral) || (a.Expr is MethodGroupExpr))
2058                                         continue;
2059
2060                                 Type pt = pd.ParameterType (i);
2061                                 Type at = a.Type;
2062
2063                                 if (!InferType (pt, at, infered_types))
2064                                         return false;
2065                         }
2066
2067                         Type element_type = TypeManager.GetElementType (pd.ParameterType (pd_count - 1));
2068
2069                         for (int i = pd_count - 1; i < arg_count; i++) {
2070                                 Argument a = (Argument) arguments [i];
2071
2072                                 if ((a.Expr is NullLiteral) || (a.Expr is MethodGroupExpr))
2073                                         continue;
2074
2075                                 if (!InferType (element_type, a.Type, infered_types))
2076                                         return false;
2077                         }
2078
2079                         for (int i = 0; i < infered_types.Length; i++)
2080                                 if (infered_types [i] == null)
2081                                         return false;
2082
2083                         method = method.BindGenericParameters (infered_types);
2084                         return true;
2085                 }
2086
2087                 public static bool InferTypeArguments (Type[] param_types, Type[] arg_types, Type[] infered_types)
2088                 {
2089                         if (infered_types == null)
2090                                 return false;
2091
2092                         for (int i = 0; i < arg_types.Length; i++) {
2093                                 if (arg_types [i] == null)
2094                                         continue;
2095
2096                                 if (!InferType (param_types [i], arg_types [i], infered_types))
2097                                         return false;
2098                         }
2099
2100                         for (int i = 0; i < infered_types.Length; i++)
2101                                 if (infered_types [i] == null)
2102                                         return false;
2103
2104                         return true;
2105                 }
2106
2107                 public static bool InferTypeArguments (EmitContext ec, ArrayList arguments,
2108                                                        ref MethodBase method)
2109                 {
2110                         if (!TypeManager.IsGenericMethod (method))
2111                                 return true;
2112
2113                         int arg_count;
2114                         if (arguments != null)
2115                                 arg_count = arguments.Count;
2116                         else
2117                                 arg_count = 0;
2118
2119                         ParameterData pd = Invocation.GetParameterData (method);
2120                         if (arg_count != pd.Count)
2121                                 return false;
2122
2123                         Type[] method_args = method.GetGenericArguments ();
2124
2125                         bool is_open = false;
2126                         for (int i = 0; i < method_args.Length; i++) {
2127                                 if (method_args [i].IsGenericParameter) {
2128                                         is_open = true;
2129                                         break;
2130                                 }
2131                         }
2132                         if (!is_open)
2133                                 return true;
2134
2135                         Type[] infered_types = new Type [method_args.Length];
2136
2137                         Type[] param_types = new Type [pd.Count];
2138                         Type[] arg_types = new Type [pd.Count];
2139
2140                         for (int i = 0; i < arg_count; i++) {
2141                                 param_types [i] = pd.ParameterType (i);
2142
2143                                 Argument a = (Argument) arguments [i];
2144                                 if ((a.Expr is NullLiteral) || (a.Expr is MethodGroupExpr))
2145                                         continue;
2146
2147                                 arg_types [i] = a.Type;
2148                         }
2149
2150                         if (!InferTypeArguments (param_types, arg_types, infered_types))
2151                                 return false;
2152
2153                         method = method.BindGenericParameters (infered_types);
2154                         return true;
2155                 }
2156
2157                 public static bool InferTypeArguments (EmitContext ec, ParameterData apd,
2158                                                        ref MethodBase method)
2159                 {
2160                         if (!TypeManager.IsGenericMethod (method))
2161                                 return true;
2162
2163                         ParameterData pd = Invocation.GetParameterData (method);
2164                         if (apd.Count != pd.Count)
2165                                 return false;
2166
2167                         Type[] method_args = method.GetGenericArguments ();
2168                         Type[] infered_types = new Type [method_args.Length];
2169
2170                         Type[] param_types = new Type [pd.Count];
2171                         Type[] arg_types = new Type [pd.Count];
2172
2173                         for (int i = 0; i < apd.Count; i++) {
2174                                 param_types [i] = pd.ParameterType (i);
2175                                 arg_types [i] = apd.ParameterType (i);
2176                         }
2177
2178                         if (!InferTypeArguments (param_types, arg_types, infered_types))
2179                                 return false;
2180
2181                         method = method.BindGenericParameters (infered_types);
2182                         return true;
2183                 }
2184         }
2185 }