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2010-06-21 Atsushi Enomoto <atsushi@ximian.com>
[mcs.git] / mcs / generic.cs
blob797a285cc441e54111d02fa0b8072d2f0f7519ea
1 //
2 // generic.cs: Generics support
3 //
4 // Authors: Martin Baulig (martin@ximian.com)
5 // Miguel de Icaza (miguel@ximian.com)
6 // Marek Safar (marek.safar@gmail.com)
7 //
8 // Dual licensed under the terms of the MIT X11 or GNU GPL
9 //
10 // Copyright 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
11 // Copyright 2004-2008 Novell, Inc
12 //
13 using System;
14 using System.Reflection;
15 using System.Reflection.Emit;
16 using System.Globalization;
17 using System.Collections.Generic;
18 using System.Text;
19 using System.Linq;
20
21 namespace Mono.CSharp {
22 public enum Variance
23 {
24 //
25 // Don't add or modify internal values, they are used as -/+ calculation signs
26 //
27 None = 0,
28 Covariant = 1,
29 Contravariant = -1
30 }
31
32 [Flags]
33 public enum SpecialConstraint
34 {
35 None = 0,
36 Constructor = 1 << 2,
37 Class = 1 << 3,
38 Struct = 1 << 4
39 }
40
41 public class SpecialContraintExpr : FullNamedExpression
42 {
43 public SpecialContraintExpr (SpecialConstraint constraint, Location loc)
44 {
45 this.loc = loc;
46 this.Constraint = constraint;
47 }
48
49 public SpecialConstraint Constraint { get; private set; }
50
51 protected override Expression DoResolve (ResolveContext rc)
52 {
53 throw new NotImplementedException ();
54 }
55 }
56
57 //
58 // A set of parsed constraints for a type parameter
59 //
60 public class Constraints
61 {
62 SimpleMemberName tparam;
63 List<FullNamedExpression> constraints;
64 Location loc;
65 bool resolved;
66 bool resolving;
67
68 public Constraints (SimpleMemberName tparam, List<FullNamedExpression> constraints, Location loc)
69 {
70 this.tparam = tparam;
71 this.constraints = constraints;
72 this.loc = loc;
73 }
74
75 #region Properties
76
77 public Location Location {
78 get {
79 return loc;
80 }
81 }
82
83 public SimpleMemberName TypeParameter {
84 get {
85 return tparam;
86 }
87 }
88
89 #endregion
90
91 bool CheckConflictingInheritedConstraint (TypeSpec ba, TypeSpec bb, IMemberContext context, Location loc)
92 {
93 if (!TypeManager.IsSubclassOf (ba, bb) && !TypeManager.IsSubclassOf (bb, ba)) {
94 context.Compiler.Report.Error (455, loc,
95 "Type parameter `{0}' inherits conflicting constraints `{1}' and `{2}'",
96 tparam.Value,
97 ba.GetSignatureForError (), bb.GetSignatureForError ());
98 return false;
99 }
100
101 return true;
102 }
103
104 public void CheckGenericConstraints (IMemberContext context)
105 {
106 foreach (var c in constraints) {
107 var ge = c as GenericTypeExpr;
108 if (ge != null)
109 ge.CheckConstraints (context);
110 }
111 }
112
113 //
114 // Resolve the constraints types with only possible early checks, return
115 // value `false' is reserved for recursive failure
116 //
117 public bool Resolve (IMemberContext context, TypeParameter tp)
118 {
119 if (resolved)
120 return true;
121
122 if (resolving)
123 return false;
124
125 resolving = true;
126 var spec = tp.Type;
127 List<TypeParameterSpec> tparam_types = null;
128 bool iface_found = false;
129
130 spec.BaseType = TypeManager.object_type;
131
132 for (int i = 0; i < constraints.Count; ++i) {
133 var constraint = constraints[i];
134
135 if (constraint is SpecialContraintExpr) {
136 spec.SpecialConstraint |= ((SpecialContraintExpr) constraint).Constraint;
137 if (spec.HasSpecialStruct)
138 spec.BaseType = TypeManager.value_type;
139
140 // Set to null as it does not have a type
141 constraints[i] = null;
142 continue;
143 }
144
145 var type_expr = constraints[i] = constraint.ResolveAsTypeTerminal (context, false);
146 if (type_expr == null)
147 continue;
148
149 var gexpr = type_expr as GenericTypeExpr;
150 if (gexpr != null && gexpr.HasDynamicArguments ()) {
151 context.Compiler.Report.Error (1968, constraint.Location,
152 "A constraint cannot be the dynamic type `{0}'", gexpr.GetSignatureForError ());
153 continue;
154 }
155
156 var type = type_expr.Type;
157
158 if (!context.CurrentMemberDefinition.IsAccessibleAs (type)) {
159 context.Compiler.Report.SymbolRelatedToPreviousError (type);
160 context.Compiler.Report.Error (703, loc,
161 "Inconsistent accessibility: constraint type `{0}' is less accessible than `{1}'",
162 type.GetSignatureForError (), context.GetSignatureForError ());
163 }
164
165 if (type.IsInterface) {
166 if (!spec.AddInterface (type)) {
167 context.Compiler.Report.Error (405, constraint.Location,
168 "Duplicate constraint `{0}' for type parameter `{1}'", type.GetSignatureForError (), tparam.Value);
169 }
170
171 iface_found = true;
172 continue;
173 }
174
175
176 var constraint_tp = type as TypeParameterSpec;
177 if (constraint_tp != null) {
178 if (tparam_types == null) {
179 tparam_types = new List<TypeParameterSpec> (2);
180 } else if (tparam_types.Contains (constraint_tp)) {
181 context.Compiler.Report.Error (405, constraint.Location,
182 "Duplicate constraint `{0}' for type parameter `{1}'", type.GetSignatureForError (), tparam.Value);
183 continue;
184 }
185
186 //
187 // Checks whether each generic method parameter constraint type
188 // is valid with respect to T
189 //
190 if (tp.IsMethodTypeParameter) {
191 TypeManager.CheckTypeVariance (type, Variance.Contravariant, context);
192 }
193
194 var tp_def = constraint_tp.MemberDefinition as TypeParameter;
195 if (tp_def != null && !tp_def.ResolveConstraints (context)) {
196 context.Compiler.Report.Error (454, constraint.Location,
197 "Circular constraint dependency involving `{0}' and `{1}'",
198 constraint_tp.GetSignatureForError (), tp.GetSignatureForError ());
199 continue;
200 }
201
202 //
203 // Checks whether there are no conflicts between type parameter constraints
204 //
205 // class Foo<T, U>
206 // where T : A
207 // where U : B, T
208 //
209 // A and B are not convertible and only 1 class constraint is allowed
210 //
211 if (constraint_tp.HasTypeConstraint) {
212 if (spec.HasTypeConstraint || spec.HasSpecialStruct) {
213 if (!CheckConflictingInheritedConstraint (spec.BaseType, constraint_tp.BaseType, context, constraint.Location))
214 continue;
215 } else {
216 for (int ii = 0; ii < tparam_types.Count; ++ii) {
217 if (!tparam_types[ii].HasTypeConstraint)
218 continue;
219
220 if (!CheckConflictingInheritedConstraint (tparam_types[ii].BaseType, constraint_tp.BaseType, context, constraint.Location))
221 break;
222 }
223 }
224 }
225
226 if (constraint_tp.HasSpecialStruct) {
227 context.Compiler.Report.Error (456, constraint.Location,
228 "Type parameter `{0}' has the `struct' constraint, so it cannot be used as a constraint for `{1}'",
229 constraint_tp.GetSignatureForError (), tp.GetSignatureForError ());
230 continue;
231 }
232
233 tparam_types.Add (constraint_tp);
234 continue;
235 }
236
237 if (iface_found || spec.HasTypeConstraint) {
238 context.Compiler.Report.Error (406, constraint.Location,
239 "The class type constraint `{0}' must be listed before any other constraints. Consider moving type constraint to the beginning of the constraint list",
240 type.GetSignatureForError ());
241 }
242
243 if (spec.HasSpecialStruct || spec.HasSpecialClass) {
244 context.Compiler.Report.Error (450, type_expr.Location,
245 "`{0}': cannot specify both a constraint class and the `class' or `struct' constraint",
246 type.GetSignatureForError ());
247 }
248
249 if (type == InternalType.Dynamic) {
250 context.Compiler.Report.Error (1967, constraint.Location, "A constraint cannot be the dynamic type");
251 continue;
252 }
253
254 if (type.IsSealed || !type.IsClass) {
255 context.Compiler.Report.Error (701, loc,
256 "`{0}' is not a valid constraint. A constraint must be an interface, a non-sealed class or a type parameter",
257 TypeManager.CSharpName (type));
258 continue;
259 }
260
261 if (type.IsStatic) {
262 context.Compiler.Report.Error (717, constraint.Location,
263 "`{0}' is not a valid constraint. Static classes cannot be used as constraints",
264 type.GetSignatureForError ());
265 } else if (type == TypeManager.array_type || type == TypeManager.delegate_type ||
266 type == TypeManager.enum_type || type == TypeManager.value_type ||
267 type == TypeManager.object_type || type == TypeManager.multicast_delegate_type) {
268 context.Compiler.Report.Error (702, constraint.Location,
269 "A constraint cannot be special class `{0}'", type.GetSignatureForError ());
270 continue;
271 }
272
273 spec.BaseType = type;
274 }
275
276 if (tparam_types != null)
277 spec.TypeArguments = tparam_types.ToArray ();
278
279 resolving = false;
280 resolved = true;
281 return true;
282 }
283
284 public void VerifyClsCompliance (Report report)
285 {
286 foreach (var c in constraints)
287 {
288 if (c == null)
289 continue;
290
291 if (!c.Type.IsCLSCompliant ()) {
292 report.SymbolRelatedToPreviousError (c.Type);
293 report.Warning (3024, 1, loc, "Constraint type `{0}' is not CLS-compliant",
294 c.Type.GetSignatureForError ());
295 }
296 }
297 }
298 }
299
300 //
301 // A type parameter for a generic type or generic method definition
302 //
303 public class TypeParameter : MemberCore, ITypeDefinition
304 {
305 static readonly string[] attribute_target = new string [] { "type parameter" };
306
307 Constraints constraints;
308 GenericTypeParameterBuilder builder;
309 // Variance variance;
310 TypeParameterSpec spec;
311
312 public TypeParameter (DeclSpace parent, int index, MemberName name, Constraints constraints, Attributes attrs, Variance variance)
313 : base (parent, name, attrs)
314 {
315 this.constraints = constraints;
316 // this.variance = variance;
317 this.spec = new TypeParameterSpec (null, index, this, SpecialConstraint.None, variance, null);
318 }
319
320 #region Properties
321
322 public override AttributeTargets AttributeTargets {
323 get {
324 return AttributeTargets.GenericParameter;
325 }
326 }
327
328 public override string DocCommentHeader {
329 get {
330 throw new InvalidOperationException (
331 "Unexpected attempt to get doc comment from " + this.GetType ());
332 }
333 }
334
335 public bool IsMethodTypeParameter {
336 get {
337 return spec.IsMethodOwned;
338 }
339 }
340
341 public string Namespace {
342 get {
343 return null;
344 }
345 }
346
347 public TypeParameterSpec Type {
348 get {
349 return spec;
350 }
351 }
352
353 public int TypeParametersCount {
354 get {
355 return 0;
356 }
357 }
358
359 public TypeParameterSpec[] TypeParameters {
360 get {
361 return null;
362 }
363 }
364
365 public override string[] ValidAttributeTargets {
366 get {
367 return attribute_target;
368 }
369 }
370
371 public Variance Variance {
372 get {
373 return spec.Variance;
374 }
375 }
376
377 #endregion
378
379 //
380 // This is called for each part of a partial generic type definition.
381 //
382 // If partial type parameters constraints are not null and we don't
383 // already have constraints they become our constraints. If we already
384 // have constraints, we must check that they're the same.
385 //
386 public bool AddPartialConstraints (TypeContainer part, TypeParameter tp)
387 {
388 if (builder == null)
389 throw new InvalidOperationException ();
390
391 var new_constraints = tp.constraints;
392 if (new_constraints == null)
393 return true;
394
395 // TODO: could create spec only
396 //tp.Define (null, -1, part.Definition);
397 tp.spec.DeclaringType = part.Definition;
398 if (!tp.ResolveConstraints (part))
399 return false;
400
401 if (constraints != null)
402 return spec.HasSameConstraintsDefinition (tp.Type);
403
404 // Copy constraint from resolved part to partial container
405 spec.SpecialConstraint = tp.spec.SpecialConstraint;
406 spec.InterfacesDefined = tp.spec.InterfacesDefined;
407 spec.TypeArguments = tp.spec.TypeArguments;
408 spec.BaseType = tp.spec.BaseType;
409
410 return true;
411 }
412
413 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
414 {
415 builder.SetCustomAttribute ((ConstructorInfo) ctor.GetMetaInfo (), cdata);
416 }
417
418 public void CheckGenericConstraints ()
419 {
420 if (constraints != null)
421 constraints.CheckGenericConstraints (this);
422 }
423
424 public TypeParameter CreateHoistedCopy (TypeSpec declaringType)
425 {
426 return new TypeParameter (Parent, spec.DeclaredPosition, MemberName, constraints, null, spec.Variance) {
427 spec = new TypeParameterSpec (declaringType, spec.DeclaredPosition, spec.MemberDefinition, spec.SpecialConstraint, spec.Variance, null) {
428 BaseType = spec.BaseType,
429 InterfacesDefined = spec.InterfacesDefined,
430 TypeArguments = spec.TypeArguments
431 }
432 };
433 }
434
435 public override bool Define ()
436 {
437 return true;
438 }
439
440 //
441 // This is the first method which is called during the resolving
442 // process; we're called immediately after creating the type parameters
443 // with SRE (by calling `DefineGenericParameters()' on the TypeBuilder /
444 // MethodBuilder).
445 //
446 public void Define (GenericTypeParameterBuilder type, TypeSpec declaringType)
447 {
448 if (builder != null)
449 throw new InternalErrorException ();
450
451 this.builder = type;
452 spec.DeclaringType = declaringType;
453 spec.SetMetaInfo (type);
454 }
455
456 public void EmitConstraints (GenericTypeParameterBuilder builder)
457 {
458 var attr = GenericParameterAttributes.None;
459 if (spec.Variance == Variance.Contravariant)
460 attr |= GenericParameterAttributes.Contravariant;
461 else if (spec.Variance == Variance.Covariant)
462 attr |= GenericParameterAttributes.Covariant;
463
464 if (spec.HasSpecialClass)
465 attr |= GenericParameterAttributes.ReferenceTypeConstraint;
466 else if (spec.HasSpecialStruct)
467 attr |= GenericParameterAttributes.NotNullableValueTypeConstraint | GenericParameterAttributes.DefaultConstructorConstraint;
468
469 if (spec.HasSpecialConstructor)
470 attr |= GenericParameterAttributes.DefaultConstructorConstraint;
471
472 if (spec.BaseType != TypeManager.object_type)
473 builder.SetBaseTypeConstraint (spec.BaseType.GetMetaInfo ());
474
475 if (spec.InterfacesDefined != null)
476 builder.SetInterfaceConstraints (spec.InterfacesDefined.Select (l => l.GetMetaInfo ()).ToArray ());
477
478 if (spec.TypeArguments != null)
479 builder.SetInterfaceConstraints (spec.TypeArguments.Select (l => l.GetMetaInfo ()).ToArray ());
480
481 builder.SetGenericParameterAttributes (attr);
482 }
483
484 public override void Emit ()
485 {
486 EmitConstraints (builder);
487
488 if (OptAttributes != null)
489 OptAttributes.Emit ();
490
491 base.Emit ();
492 }
493
494 public void ErrorInvalidVariance (IMemberContext mc, Variance expected)
495 {
496 Report.SymbolRelatedToPreviousError (mc.CurrentMemberDefinition);
497 string input_variance = Variance == Variance.Contravariant ? "contravariant" : "covariant";
498 string gtype_variance;
499 switch (expected) {
500 case Variance.Contravariant: gtype_variance = "contravariantly"; break;
501 case Variance.Covariant: gtype_variance = "covariantly"; break;
502 default: gtype_variance = "invariantly"; break;
503 }
504
505 Delegate d = mc as Delegate;
506 string parameters = d != null ? d.Parameters.GetSignatureForError () : "";
507
508 Report.Error (1961, Location,
509 "The {2} type parameter `{0}' must be {3} valid on `{1}{4}'",
510 GetSignatureForError (), mc.GetSignatureForError (), input_variance, gtype_variance, parameters);
511 }
512
513 public TypeSpec GetAttributeCoClass ()
514 {
515 return null;
516 }
517
518 public string GetAttributeDefaultMember ()
519 {
520 throw new NotSupportedException ();
521 }
522
523 public AttributeUsageAttribute GetAttributeUsage (PredefinedAttribute pa)
524 {
525 throw new NotSupportedException ();
526 }
527
528 public override string GetSignatureForError ()
529 {
530 return MemberName.Name;
531 }
532
533 public MemberCache LoadMembers (TypeSpec declaringType)
534 {
535 throw new NotSupportedException ("Not supported for compiled definition");
536 }
537
538 //
539 // Resolves all type parameter constraints
540 //
541 public bool ResolveConstraints (IMemberContext context)
542 {
543 if (constraints != null)
544 return constraints.Resolve (context, this);
545
546 spec.BaseType = TypeManager.object_type;
547 return true;
548 }
549
550 public static TypeParameter FindTypeParameter (TypeParameter[] tparams, string name)
551 {
552 foreach (var tp in tparams) {
553 if (tp.Name == name)
554 return tp;
555 }
556
557 return null;
558 }
559
560 public override bool IsClsComplianceRequired ()
561 {
562 return false;
563 }
564
565 public new void VerifyClsCompliance ()
566 {
567 if (constraints != null)
568 constraints.VerifyClsCompliance (Report);
569 }
570 }
571
572 [System.Diagnostics.DebuggerDisplay ("{DisplayDebugInfo()}")]
573 public class TypeParameterSpec : TypeSpec
574 {
575 public static readonly new TypeParameterSpec[] EmptyTypes = new TypeParameterSpec[0];
576
577 Variance variance;
578 SpecialConstraint spec;
579 readonly int tp_pos;
580 TypeSpec[] targs;
581 TypeSpec[] ifaces_defined;
582
583 //
584 // Creates type owned type parameter
585 //
586 public TypeParameterSpec (TypeSpec declaringType, int index, ITypeDefinition definition, SpecialConstraint spec, Variance variance, Type info)
587 : base (MemberKind.TypeParameter, declaringType, definition, info, Modifiers.PUBLIC)
588 {
589 this.variance = variance;
590 this.spec = spec;
591 state &= ~StateFlags.Obsolete_Undetected;
592 tp_pos = index;
593 }
594
595 //
596 // Creates method owned type parameter
597 //
598 public TypeParameterSpec (int index, ITypeDefinition definition, SpecialConstraint spec, Variance variance, Type info)
599 : this (null, index, definition, spec, variance, info)
600 {
601 }
602
603 #region Properties
604
605 public int DeclaredPosition {
606 get {
607 return tp_pos;
608 }
609 }
610
611 public bool HasSpecialConstructor {
612 get {
613 return (spec & SpecialConstraint.Constructor) != 0;
614 }
615 }
616
617 public bool HasSpecialClass {
618 get {
619 return (spec & SpecialConstraint.Class) != 0;
620 }
621 }
622
623 public bool HasSpecialStruct {
624 get {
625 return (spec & SpecialConstraint.Struct) != 0;
626 }
627 }
628
629 public bool HasTypeConstraint {
630 get {
631 return BaseType != TypeManager.object_type && BaseType != TypeManager.value_type;
632 }
633 }
634
635 public override IList<TypeSpec> Interfaces {
636 get {
637 if ((state & StateFlags.InterfacesExpanded) == 0) {
638 if (ifaces != null) {
639 for (int i = 0; i < ifaces.Count; ++i ) {
640 var iface_type = ifaces[i];
641 if (iface_type.Interfaces != null) {
642 if (ifaces_defined == null)
643 ifaces_defined = ifaces.ToArray ();
644
645 for (int ii = 0; ii < iface_type.Interfaces.Count; ++ii) {
646 var ii_iface_type = iface_type.Interfaces [ii];
647
648 AddInterface (ii_iface_type);
649 }
650 }
651 }
652 }
653
654 if (ifaces_defined == null && ifaces != null)
655 ifaces_defined = ifaces.ToArray ();
656
657 state |= StateFlags.InterfacesExpanded;
658 }
659
660 return ifaces;
661 }
662 }
663
664 //
665 // Unexpanded interfaces list
666 //
667 public TypeSpec[] InterfacesDefined {
668 get {
669 if (ifaces_defined == null && ifaces != null)
670 ifaces_defined = ifaces.ToArray ();
671
672 return ifaces_defined;
673 }
674 set {
675 ifaces_defined = value;
676 }
677 }
678
679 public bool IsConstrained {
680 get {
681 return spec != SpecialConstraint.None || ifaces != null || targs != null || HasTypeConstraint;
682 }
683 }
684
685 //
686 // Returns whether the type parameter is "known to be a reference type"
687 //
688 public bool IsReferenceType {
689 get {
690 return (spec & SpecialConstraint.Class) != 0 || HasTypeConstraint;
691 }
692 }
693
694 public bool IsValueType { // TODO: Do I need this ?
695 get {
696 // TODO MemberCache: probably wrong
697 return HasSpecialStruct;
698 }
699 }
700
701 public override string Name {
702 get {
703 return definition.Name;
704 }
705 }
706
707 public bool IsMethodOwned {
708 get {
709 return DeclaringType == null;
710 }
711 }
712
713 public SpecialConstraint SpecialConstraint {
714 get {
715 return spec;
716 }
717 set {
718 spec = value;
719 }
720 }
721
722 //
723 // Types used to inflate the generic type
724 //
725 public new TypeSpec[] TypeArguments {
726 get {
727 return targs;
728 }
729 set {
730 targs = value;
731 }
732 }
733
734 public Variance Variance {
735 get {
736 return variance;
737 }
738 }
739
740 #endregion
741
742 public string DisplayDebugInfo ()
743 {
744 var s = GetSignatureForError ();
745 return IsMethodOwned ? s + "!!" : s + "!";
746 }
747
748 //
749 // Finds effective base class
750 //
751 public TypeSpec GetEffectiveBase ()
752 {
753 if (HasSpecialStruct) {
754 return TypeManager.value_type;
755 }
756
757 if (BaseType != null && targs == null)
758 return BaseType;
759
760 var types = targs;
761 if (HasTypeConstraint) {
762 Array.Resize (ref types, types.Length + 1);
763 types[types.Length - 1] = BaseType;
764 }
765
766 if (types != null)
767 return Convert.FindMostEncompassedType (types.Select (l => l.BaseType));
768
769 return TypeManager.object_type;
770 }
771
772 public override string GetSignatureForError ()
773 {
774 return Name;
775 }
776
777 //
778 // Constraints have to match by definition but not position, used by
779 // partial classes or methods
780 //
781 public bool HasSameConstraintsDefinition (TypeParameterSpec other)
782 {
783 if (spec != other.spec)
784 return false;
785
786 if (BaseType != other.BaseType)
787 return false;
788
789 if (!TypeSpecComparer.Override.IsSame (InterfacesDefined, other.InterfacesDefined))
790 return false;
791
792 if (!TypeSpecComparer.Override.IsSame (targs, other.targs))
793 return false;
794
795 return true;
796 }
797
798 //
799 // Constraints have to match by using same set of types, used by
800 // implicit interface implementation
801 //
802 public bool HasSameConstraintsImplementation (TypeParameterSpec other)
803 {
804 if (spec != other.spec)
805 return false;
806
807 //
808 // It can be same base type or inflated type parameter
809 //
810 // interface I<T> { void Foo<U> where U : T; }
811 // class A : I<int> { void Foo<X> where X : int {} }
812 //
813 bool found;
814 if (!TypeSpecComparer.Override.IsEqual (BaseType, other.BaseType)) {
815 if (other.targs == null)
816 return false;
817
818 found = false;
819 foreach (var otarg in other.targs) {
820 if (TypeSpecComparer.Override.IsEqual (BaseType, otarg)) {
821 found = true;
822 break;
823 }
824 }
825
826 if (!found)
827 return false;
828 }
829
830 // Check interfaces implementation -> definition
831 if (InterfacesDefined != null) {
832 foreach (var iface in InterfacesDefined) {
833 found = false;
834 if (other.InterfacesDefined != null) {
835 foreach (var oiface in other.InterfacesDefined) {
836 if (TypeSpecComparer.Override.IsEqual (iface, oiface)) {
837 found = true;
838 break;
839 }
840 }
841 }
842
843 if (found)
844 continue;
845
846 if (other.targs != null) {
847 foreach (var otarg in other.targs) {
848 if (TypeSpecComparer.Override.IsEqual (BaseType, otarg)) {
849 found = true;
850 break;
851 }
852 }
853 }
854
855 if (!found)
856 return false;
857 }
858 }
859
860 // Check interfaces implementation <- definition
861 if (other.InterfacesDefined != null) {
862 if (InterfacesDefined == null)
863 return false;
864
865 foreach (var oiface in other.InterfacesDefined) {
866 found = false;
867 foreach (var iface in InterfacesDefined) {
868 if (TypeSpecComparer.Override.IsEqual (iface, oiface)) {
869 found = true;
870 break;
871 }
872 }
873
874 if (!found)
875 return false;
876 }
877 }
878
879 // Check type parameters implementation -> definition
880 if (targs != null) {
881 if (other.targs == null)
882 return false;
883
884 foreach (var targ in targs) {
885 found = false;
886 foreach (var otarg in other.targs) {
887 if (TypeSpecComparer.Override.IsEqual (targ, otarg)) {
888 found = true;
889 break;
890 }
891 }
892
893 if (!found)
894 return false;
895 }
896 }
897
898 // Check type parameters implementation <- definition
899 if (other.targs != null) {
900 foreach (var otarg in other.targs) {
901 // Ignore inflated type arguments, were checked above
902 if (!otarg.IsGenericParameter)
903 continue;
904
905 if (targs == null)
906 return false;
907
908 found = false;
909 foreach (var targ in targs) {
910 if (TypeSpecComparer.Override.IsEqual (targ, otarg)) {
911 found = true;
912 break;
913 }
914 }
915
916 if (!found)
917 return false;
918 }
919 }
920
921 return true;
922 }
923
924 public static TypeParameterSpec[] InflateConstraints (TypeParameterInflator inflator, TypeParameterSpec[] tparams)
925 {
926 TypeParameterSpec[] constraints = null;
927
928 for (int i = 0; i < tparams.Length; ++i) {
929 var tp = tparams[i];
930 if (tp.HasTypeConstraint || tp.Interfaces != null || tp.TypeArguments != null) {
931 if (constraints == null) {
932 constraints = new TypeParameterSpec[tparams.Length];
933 Array.Copy (tparams, constraints, constraints.Length);
934 }
935
936 constraints[i] = (TypeParameterSpec) constraints[i].InflateMember (inflator);
937 }
938 }
939
940 if (constraints == null)
941 constraints = tparams;
942
943 return constraints;
944 }
945
946 public void InflateConstraints (TypeParameterInflator inflator, TypeParameterSpec tps)
947 {
948 tps.BaseType = inflator.Inflate (BaseType);
949 if (ifaces != null) {
950 tps.ifaces = new List<TypeSpec> (ifaces.Count);
951 for (int i = 0; i < ifaces.Count; ++i)
952 tps.ifaces.Add (inflator.Inflate (ifaces[i]));
953 }
954 if (targs != null) {
955 tps.targs = new TypeSpec[targs.Length];
956 for (int i = 0; i < targs.Length; ++i)
957 tps.targs[i] = inflator.Inflate (targs[i]);
958 }
959 }
960
961 public override MemberSpec InflateMember (TypeParameterInflator inflator)
962 {
963 var tps = (TypeParameterSpec) MemberwiseClone ();
964 InflateConstraints (inflator, tps);
965 return tps;
966 }
967
968 //
969 // Populates type parameter members using type parameter constraints
970 // The trick here is to be called late enough but not too late to
971 // populate member cache with all members from other types
972 //
973 protected override void InitializeMemberCache (bool onlyTypes)
974 {
975 cache = new MemberCache ();
976 if (ifaces != null) {
977 foreach (var iface_type in Interfaces) {
978 cache.AddInterface (iface_type);
979 }
980 }
981 }
982
983 public bool IsConvertibleToInterface (TypeSpec iface)
984 {
985 if (Interfaces != null) {
986 foreach (var t in Interfaces) {
987 if (t == iface)
988 return true;
989 }
990 }
991
992 if (TypeArguments != null) {
993 foreach (var t in TypeArguments) {
994 if (((TypeParameterSpec) t).IsConvertibleToInterface (iface))
995 return true;
996 }
997 }
998
999 return false;
1000 }
1001
1002 public override TypeSpec Mutate (TypeParameterMutator mutator)
1003 {
1004 return mutator.Mutate (this);
1005 }
1006 }
1007
1008 public struct TypeParameterInflator
1009 {
1010 readonly TypeSpec type;
1011 readonly TypeParameterSpec[] tparams;
1012 readonly TypeSpec[] targs;
1013
1014 public TypeParameterInflator (TypeParameterInflator nested, TypeSpec type)
1015 : this (type, nested.tparams, nested.targs)
1016 {
1017 }
1018
1019 public TypeParameterInflator (TypeSpec type, TypeParameterSpec[] tparams, TypeSpec[] targs)
1020 {
1021 if (tparams.Length != targs.Length)
1022 throw new ArgumentException ("Invalid arguments");
1023
1024 this.tparams = tparams;
1025 this.targs = targs;
1026 this.type = type;
1027 }
1028
1029 //
1030 // Type parameters to inflate
1031 //
1032 public TypeParameterSpec[] TypeParameters {
1033 get {
1034 return tparams;
1035 }
1036 }
1037
1038 public TypeSpec Inflate (TypeSpec ts)
1039 {
1040 var tp = ts as TypeParameterSpec;
1041 if (tp != null)
1042 return Inflate (tp);
1043
1044 var ac = ts as ArrayContainer;
1045 if (ac != null) {
1046 var et = Inflate (ac.Element);
1047 if (et != ac.Element)
1048 return ArrayContainer.MakeType (et, ac.Rank);
1049
1050 return ac;
1051 }
1052
1053 //
1054 // When inflating a nested type, inflate its parent first
1055 // in case it's using same type parameters (was inflated within the type)
1056 //
1057 if (ts.IsNested) {
1058 var parent = Inflate (ts.DeclaringType);
1059 if (ts.DeclaringType != parent) {
1060 //
1061 // Keep the inflated type arguments
1062 //
1063 var targs = ts.TypeArguments;
1064
1065 //
1066 // Parent was inflated, find the same type on inflated type
1067 // to use same cache for nested types on same generic parent
1068 //
1069 // TODO: Should use BindingRestriction.DeclaredOnly or GetMember
1070 ts = MemberCache.FindNestedType (parent, ts.Name, targs.Length);
1071
1072 //
1073 // Handle the tricky case where parent shares local type arguments
1074 // which means inflating inflated type
1075 //
1076 // class Test<T> {
1077 // public static Nested<T> Foo () { return null; }
1078 //
1079 // public class Nested<U> {}
1080 // }
1081 //
1082 // return type of Test<string>.Foo() has to be Test<string>.Nested<string>
1083 //
1084 if (targs.Length > 0) {
1085 var inflated_targs = new TypeSpec [targs.Length];
1086 for (var i = 0; i < targs.Length; ++i)
1087 inflated_targs[i] = Inflate (targs[i]);
1088
1089 ts = ts.MakeGenericType (inflated_targs);
1090 }
1091
1092 return ts;
1093 }
1094 }
1095
1096 // Inflate generic type
1097 if (ts.Arity > 0)
1098 return InflateTypeParameters (ts);
1099
1100 return ts;
1101 }
1102
1103 public TypeSpec Inflate (TypeParameterSpec tp)
1104 {
1105 for (int i = 0; i < tparams.Length; ++i)
1106 if (tparams [i] == tp)
1107 return targs[i];
1108
1109 // This can happen when inflating nested types
1110 // without type arguments specified
1111 return tp;
1112 }
1113
1114 //
1115 // Inflates generic types
1116 //
1117 TypeSpec InflateTypeParameters (TypeSpec type)
1118 {
1119 var targs = new TypeSpec[type.Arity];
1120 var i = 0;
1121
1122 var gti = type as InflatedTypeSpec;
1123
1124 //
1125 // Inflating using outside type arguments, var v = new Foo<int> (), class Foo<T> {}
1126 //
1127 if (gti != null) {
1128 for (; i < targs.Length; ++i)
1129 targs[i] = Inflate (gti.TypeArguments[i]);
1130
1131 return gti.GetDefinition ().MakeGenericType (targs);
1132 }
1133
1134 //
1135 // Inflating parent using inside type arguments, class Foo<T> { ITest<T> foo; }
1136 //
1137 var args = type.MemberDefinition.TypeParameters;
1138 foreach (var ds_tp in args)
1139 targs[i++] = Inflate (ds_tp);
1140
1141 return type.MakeGenericType (targs);
1142 }
1143
1144 public TypeSpec TypeInstance {
1145 get { return type; }
1146 }
1147 }
1148
1149 //
1150 // Before emitting any code we have to change all MVAR references to VAR
1151 // when the method is of generic type and has hoisted variables
1152 //
1153 public class TypeParameterMutator
1154 {
1155 TypeParameter[] mvar;
1156 TypeParameter[] var;
1157 Dictionary<TypeSpec, TypeSpec> mutated_typespec = new Dictionary<TypeSpec, TypeSpec> ();
1158
1159 public TypeParameterMutator (TypeParameter[] mvar, TypeParameter[] var)
1160 {
1161 if (mvar.Length != var.Length)
1162 throw new ArgumentException ();
1163
1164 this.mvar = mvar;
1165 this.var = var;
1166 }
1167
1168 public TypeSpec Mutate (TypeSpec ts)
1169 {
1170 TypeSpec value;
1171 if (mutated_typespec.TryGetValue (ts, out value))
1172 return value;
1173
1174 value = ts.Mutate (this);
1175 mutated_typespec.Add (ts, value);
1176 return value;
1177 }
1178
1179 public FieldInfo Mutate (FieldSpec fs)
1180 {
1181 // TODO:
1182 return fs.GetMetaInfo ();
1183 }
1184
1185 public TypeParameterSpec Mutate (TypeParameterSpec tp)
1186 {
1187 for (int i = 0; i < mvar.Length; ++i) {
1188 if (mvar[i].Type == tp)
1189 return var[i].Type;
1190 }
1191
1192 return tp;
1193 }
1194
1195 public TypeSpec[] Mutate (TypeSpec[] targs)
1196 {
1197 TypeSpec[] mutated = new TypeSpec[targs.Length];
1198 bool changed = false;
1199 for (int i = 0; i < targs.Length; ++i) {
1200 mutated[i] = Mutate (targs[i]);
1201 changed |= targs[i] != mutated[i];
1202 }
1203
1204 return changed ? mutated : targs;
1205 }
1206 }
1207
1208 /// <summary>
1209 /// A TypeExpr which already resolved to a type parameter.
1210 /// </summary>
1211 public class TypeParameterExpr : TypeExpr {
1212
1213 public TypeParameterExpr (TypeParameter type_parameter, Location loc)
1214 {
1215 this.type = type_parameter.Type;
1216 this.eclass = ExprClass.TypeParameter;
1217 this.loc = loc;
1218 }
1219
1220 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
1221 {
1222 throw new NotSupportedException ();
1223 }
1224
1225 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
1226 {
1227 return this;
1228 }
1229
1230 public override bool CheckAccessLevel (IMemberContext ds)
1231 {
1232 return true;
1233 }
1234 }
1235
1236 public class InflatedTypeSpec : TypeSpec
1237 {
1238 TypeSpec[] targs;
1239 TypeParameterSpec[] constraints;
1240 readonly TypeSpec open_type;
1241
1242 public InflatedTypeSpec (TypeSpec openType, TypeSpec declaringType, TypeSpec[] targs)
1243 : base (openType.Kind, declaringType, openType.MemberDefinition, null, openType.Modifiers)
1244 {
1245 if (targs == null)
1246 throw new ArgumentNullException ("targs");
1247
1248 // this.state = openType.state;
1249 this.open_type = openType;
1250 this.targs = targs;
1251 }
1252
1253 #region Properties
1254
1255 public override TypeSpec BaseType {
1256 get {
1257 if (cache == null || (state & StateFlags.PendingBaseTypeInflate) != 0)
1258 InitializeMemberCache (true);
1259
1260 return base.BaseType;
1261 }
1262 }
1263
1264 //
1265 // Inflated type parameters with constraints array, mapping with type arguments is based on index
1266 //
1267 public TypeParameterSpec[] Constraints {
1268 get {
1269 if (constraints == null) {
1270 var inflator = new TypeParameterInflator (this, MemberDefinition.TypeParameters, targs);
1271 constraints = TypeParameterSpec.InflateConstraints (inflator, MemberDefinition.TypeParameters);
1272 }
1273
1274 return constraints;
1275 }
1276 }
1277
1278 public override IList<TypeSpec> Interfaces {
1279 get {
1280 if (cache == null)
1281 InitializeMemberCache (true);
1282
1283 return base.Interfaces;
1284 }
1285 }
1286
1287 public override MemberCache MemberCacheTypes {
1288 get {
1289 if (cache == null)
1290 InitializeMemberCache (true);
1291
1292 return cache;
1293 }
1294 }
1295
1296 //
1297 // Types used to inflate the generic type
1298 //
1299 public override TypeSpec[] TypeArguments {
1300 get {
1301 return targs;
1302 }
1303 }
1304
1305 #endregion
1306
1307 Type CreateMetaInfo (TypeParameterMutator mutator)
1308 {
1309 //
1310 // Converts nested type arguments into right order
1311 // Foo<string, bool>.Bar<int> => string, bool, int
1312 //
1313 var all = new List<Type> ();
1314 TypeSpec type = this;
1315 TypeSpec definition = type;
1316 do {
1317 if (type.GetDefinition().IsGeneric) {
1318 all.InsertRange (0,
1319 type.TypeArguments != TypeSpec.EmptyTypes ?
1320 type.TypeArguments.Select (l => l.GetMetaInfo ()) :
1321 type.MemberDefinition.TypeParameters.Select (l => l.GetMetaInfo ()));
1322 }
1323
1324 definition = definition.GetDefinition ();
1325 type = type.DeclaringType;
1326 } while (type != null);
1327
1328 return definition.GetMetaInfo ().MakeGenericType (all.ToArray ());
1329 }
1330
1331 public override ObsoleteAttribute GetAttributeObsolete ()
1332 {
1333 return open_type.GetAttributeObsolete ();
1334 }
1335
1336 protected override bool IsNotCLSCompliant ()
1337 {
1338 if (base.IsNotCLSCompliant ())
1339 return true;
1340
1341 foreach (var ta in TypeArguments) {
1342 if (ta.MemberDefinition.IsNotCLSCompliant ())
1343 return true;
1344 }
1345
1346 return false;
1347 }
1348
1349 public override TypeSpec GetDefinition ()
1350 {
1351 return open_type;
1352 }
1353
1354 public override Type GetMetaInfo ()
1355 {
1356 if (info == null)
1357 info = CreateMetaInfo (null);
1358
1359 return info;
1360 }
1361
1362 public override string GetSignatureForError ()
1363 {
1364 if (TypeManager.IsNullableType (open_type))
1365 return targs[0].GetSignatureForError () + "?";
1366
1367 if (MemberDefinition is AnonymousTypeClass)
1368 return ((AnonymousTypeClass) MemberDefinition).GetSignatureForError ();
1369
1370 return base.GetSignatureForError ();
1371 }
1372
1373 protected override string GetTypeNameSignature ()
1374 {
1375 if (targs.Length == 0 || MemberDefinition is AnonymousTypeClass)
1376 return null;
1377
1378 return "<" + TypeManager.CSharpName (targs) + ">";
1379 }
1380
1381 protected override void InitializeMemberCache (bool onlyTypes)
1382 {
1383 if (cache == null)
1384 cache = new MemberCache (onlyTypes ? open_type.MemberCacheTypes : open_type.MemberCache);
1385
1386 TypeParameterSpec[] tparams_full;
1387 TypeSpec[] targs_full = targs;
1388 if (IsNested) {
1389 //
1390 // Special case is needed when we are inflating an open type (nested type definition)
1391 // on inflated parent. Consider following case
1392 //
1393 // Foo<T>.Bar<U> => Foo<string>.Bar<U>
1394 //
1395 // Any later inflation of Foo<string>.Bar<U> has to also inflate T if used inside Bar<U>
1396 //
1397 List<TypeSpec> merged_targs = null;
1398 List<TypeParameterSpec> merged_tparams = null;
1399
1400 var type = DeclaringType;
1401
1402 do {
1403 if (type.TypeArguments.Length > 0) {
1404 if (merged_targs == null) {
1405 merged_targs = new List<TypeSpec> ();
1406 merged_tparams = new List<TypeParameterSpec> ();
1407 if (targs.Length > 0) {
1408 merged_targs.AddRange (targs);
1409 merged_tparams.AddRange (open_type.MemberDefinition.TypeParameters);
1410 }
1411 }
1412 merged_tparams.AddRange (type.MemberDefinition.TypeParameters);
1413 merged_targs.AddRange (type.TypeArguments);
1414 }
1415 type = type.DeclaringType;
1416 } while (type != null);
1417
1418 if (merged_targs != null) {
1419 // Type arguments are not in the right order but it should not matter in this case
1420 targs_full = merged_targs.ToArray ();
1421 tparams_full = merged_tparams.ToArray ();
1422 } else if (targs.Length == 0) {
1423 tparams_full = TypeParameterSpec.EmptyTypes;
1424 } else {
1425 tparams_full = open_type.MemberDefinition.TypeParameters;
1426 }
1427 } else if (targs.Length == 0) {
1428 tparams_full = TypeParameterSpec.EmptyTypes;
1429 } else {
1430 tparams_full = open_type.MemberDefinition.TypeParameters;
1431 }
1432
1433 var inflator = new TypeParameterInflator (this, tparams_full, targs_full);
1434
1435 //
1436 // Two stage inflate due to possible nested types recursive
1437 // references
1438 //
1439 // class A<T> {
1440 // B b;
1441 // class B {
1442 // T Value;
1443 // }
1444 // }
1445 //
1446 // When resolving type of `b' members of `B' cannot be
1447 // inflated because are not yet available in membercache
1448 //
1449 if ((state & StateFlags.PendingMemberCacheMembers) == 0) {
1450 open_type.MemberCacheTypes.InflateTypes (cache, inflator);
1451
1452 //
1453 // Inflate any implemented interfaces
1454 //
1455 if (open_type.Interfaces != null) {
1456 ifaces = new List<TypeSpec> (open_type.Interfaces.Count);
1457 foreach (var iface in open_type.Interfaces) {
1458 var iface_inflated = inflator.Inflate (iface);
1459 AddInterface (iface_inflated);
1460 }
1461 }
1462
1463 //
1464 // Handles the tricky case of recursive nested base generic type
1465 //
1466 // class A<T> : Base<A<T>.Nested> {
1467 // class Nested {}
1468 // }
1469 //
1470 // When inflating A<T>. base type is not yet known, secondary
1471 // inflation is required (not common case) once base scope
1472 // is known
1473 //
1474 if (open_type.BaseType == null) {
1475 if (IsClass)
1476 state |= StateFlags.PendingBaseTypeInflate;
1477 } else {
1478 BaseType = inflator.Inflate (open_type.BaseType);
1479 }
1480 } else if ((state & StateFlags.PendingBaseTypeInflate) != 0) {
1481 BaseType = inflator.Inflate (open_type.BaseType);
1482 state &= ~StateFlags.PendingBaseTypeInflate;
1483 }
1484
1485 if (onlyTypes) {
1486 state |= StateFlags.PendingMemberCacheMembers;
1487 return;
1488 }
1489
1490 var tc = open_type.MemberDefinition as TypeContainer;
1491 if (tc != null && !tc.HasMembersDefined)
1492 throw new InternalErrorException ("Inflating MemberCache with undefined members");
1493
1494 if ((state & StateFlags.PendingBaseTypeInflate) != 0) {
1495 BaseType = inflator.Inflate (open_type.BaseType);
1496 state &= ~StateFlags.PendingBaseTypeInflate;
1497 }
1498
1499 state &= ~StateFlags.PendingMemberCacheMembers;
1500 open_type.MemberCache.InflateMembers (cache, open_type, inflator);
1501 }
1502
1503 public override TypeSpec Mutate (TypeParameterMutator mutator)
1504 {
1505 var targs = TypeArguments;
1506 if (targs != null)
1507 targs = mutator.Mutate (targs);
1508
1509 var decl = DeclaringType;
1510 if (IsNested && DeclaringType.IsGenericOrParentIsGeneric)
1511 decl = mutator.Mutate (decl);
1512
1513 if (targs == TypeArguments && decl == DeclaringType)
1514 return this;
1515
1516 var mutated = (InflatedTypeSpec) MemberwiseClone ();
1517 if (decl != DeclaringType) {
1518 // Gets back MethodInfo in case of metaInfo was inflated
1519 //mutated.info = MemberCache.GetMember<TypeSpec> (DeclaringType.GetDefinition (), this).info;
1520
1521 mutated.declaringType = decl;
1522 mutated.state |= StateFlags.PendingMetaInflate;
1523 }
1524
1525 if (targs != null) {
1526 mutated.targs = targs;
1527 mutated.info = null;
1528 }
1529
1530 return mutated;
1531 }
1532 }
1533
1534
1535 //
1536 // Tracks the type arguments when instantiating a generic type. It's used
1537 // by both type arguments and type parameters
1538 //
1539 public class TypeArguments
1540 {
1541 List<FullNamedExpression> args;
1542 TypeSpec[] atypes;
1543
1544 public TypeArguments (params FullNamedExpression[] types)
1545 {
1546 this.args = new List<FullNamedExpression> (types);
1547 }
1548
1549 public void Add (FullNamedExpression type)
1550 {
1551 args.Add (type);
1552 }
1553
1554 // TODO: Kill this monster
1555 public TypeParameterName[] GetDeclarations ()
1556 {
1557 return args.ConvertAll (i => (TypeParameterName) i).ToArray ();
1558 }
1559
1560 /// <summary>
1561 /// We may only be used after Resolve() is called and return the fully
1562 /// resolved types.
1563 /// </summary>
1564 // TODO: Not needed, just return type from resolve
1565 public TypeSpec[] Arguments {
1566 get {
1567 return atypes;
1568 }
1569 }
1570
1571 public int Count {
1572 get {
1573 return args.Count;
1574 }
1575 }
1576
1577 public virtual bool IsEmpty {
1578 get {
1579 return false;
1580 }
1581 }
1582
1583 public string GetSignatureForError()
1584 {
1585 StringBuilder sb = new StringBuilder ();
1586 for (int i = 0; i < Count; ++i) {
1587 var expr = args[i];
1588 if (expr != null)
1589 sb.Append (expr.GetSignatureForError ());
1590
1591 if (i + 1 < Count)
1592 sb.Append (',');
1593 }
1594
1595 return sb.ToString ();
1596 }
1597
1598 /// <summary>
1599 /// Resolve the type arguments.
1600 /// </summary>
1601 public virtual bool Resolve (IMemberContext ec)
1602 {
1603 if (atypes != null)
1604 return atypes.Length != 0;
1605
1606 int count = args.Count;
1607 bool ok = true;
1608
1609 atypes = new TypeSpec [count];
1610
1611 for (int i = 0; i < count; i++){
1612 TypeExpr te = args[i].ResolveAsTypeTerminal (ec, false);
1613 if (te == null) {
1614 ok = false;
1615 continue;
1616 }
1617
1618 atypes[i] = te.Type;
1619
1620 if (te.Type.IsStatic) {
1621 ec.Compiler.Report.Error (718, te.Location, "`{0}': static classes cannot be used as generic arguments",
1622 te.GetSignatureForError ());
1623 ok = false;
1624 }
1625
1626 if (te.Type.IsPointer || TypeManager.IsSpecialType (te.Type)) {
1627 ec.Compiler.Report.Error (306, te.Location,
1628 "The type `{0}' may not be used as a type argument",
1629 te.GetSignatureForError ());
1630 ok = false;
1631 }
1632 }
1633
1634 if (!ok)
1635 atypes = TypeSpec.EmptyTypes;
1636
1637 return ok;
1638 }
1639
1640 public TypeArguments Clone ()
1641 {
1642 TypeArguments copy = new TypeArguments ();
1643 foreach (var ta in args)
1644 copy.args.Add (ta);
1645
1646 return copy;
1647 }
1648 }
1649
1650 public class UnboundTypeArguments : TypeArguments
1651 {
1652 public UnboundTypeArguments (int arity)
1653 : base (new FullNamedExpression[arity])
1654 {
1655 }
1656
1657 public override bool IsEmpty {
1658 get {
1659 return true;
1660 }
1661 }
1662
1663 public override bool Resolve (IMemberContext ec)
1664 {
1665 // should not be called
1666 throw new NotSupportedException ();
1667 }
1668 }
1669
1670 public class TypeParameterName : SimpleName
1671 {
1672 Attributes attributes;
1673 Variance variance;
1674
1675 public TypeParameterName (string name, Attributes attrs, Location loc)
1676 : this (name, attrs, Variance.None, loc)
1677 {
1678 }
1679
1680 public TypeParameterName (string name, Attributes attrs, Variance variance, Location loc)
1681 : base (name, loc)
1682 {
1683 attributes = attrs;
1684 this.variance = variance;
1685 }
1686
1687 public Attributes OptAttributes {
1688 get {
1689 return attributes;
1690 }
1691 }
1692
1693 public Variance Variance {
1694 get {
1695 return variance;
1696 }
1697 }
1698 }
1699
1700 //
1701 // A type expression of generic type with type arguments
1702 //
1703 class GenericTypeExpr : TypeExpr
1704 {
1705 TypeArguments args;
1706 TypeSpec open_type;
1707 bool constraints_checked;
1708
1709 /// <summary>
1710 /// Instantiate the generic type `t' with the type arguments `args'.
1711 /// Use this constructor if you already know the fully resolved
1712 /// generic type.
1713 /// </summary>
1714 public GenericTypeExpr (TypeSpec open_type, TypeArguments args, Location l)
1715 {
1716 this.open_type = open_type;
1717 loc = l;
1718 this.args = args;
1719 }
1720
1721 public TypeArguments TypeArguments {
1722 get { return args; }
1723 }
1724
1725 public override string GetSignatureForError ()
1726 {
1727 return TypeManager.CSharpName (type);
1728 }
1729
1730 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
1731 {
1732 if (!args.Resolve (ec))
1733 return null;
1734
1735 TypeSpec[] atypes = args.Arguments;
1736
1737 //
1738 // Now bind the parameters
1739 //
1740 type = open_type.MakeGenericType (atypes);
1741
1742 //
1743 // Check constraints when context is not method/base type
1744 //
1745 if (!ec.HasUnresolvedConstraints)
1746 CheckConstraints (ec);
1747
1748 return this;
1749 }
1750
1751 //
1752 // Checks the constraints of open generic type against type
1753 // arguments. Has to be called onafter all members are defined
1754 //
1755 public bool CheckConstraints (IMemberContext ec)
1756 {
1757 if (constraints_checked)
1758 return true;
1759
1760 constraints_checked = true;
1761
1762 var gtype = (InflatedTypeSpec) type;
1763 var constraints = gtype.Constraints;
1764 if (constraints == null)
1765 return true;
1766
1767 return ConstraintChecker.CheckAll (open_type, args.Arguments, constraints, loc, ec.Compiler.Report);
1768 }
1769
1770 public override bool CheckAccessLevel (IMemberContext mc)
1771 {
1772 DeclSpace c = mc.CurrentMemberDefinition as DeclSpace;
1773 if (c == null)
1774 c = mc.CurrentMemberDefinition.Parent;
1775
1776 return c.CheckAccessLevel (open_type);
1777 }
1778
1779 public bool HasDynamicArguments ()
1780 {
1781 return HasDynamicArguments (args.Arguments);
1782 }
1783
1784 static bool HasDynamicArguments (TypeSpec[] args)
1785 {
1786 foreach (var item in args) {
1787 if (item == InternalType.Dynamic)
1788 return true;
1789
1790 if (TypeManager.IsGenericType (item))
1791 return HasDynamicArguments (TypeManager.GetTypeArguments (item));
1792 }
1793
1794 return false;
1795 }
1796
1797 public override bool Equals (object obj)
1798 {
1799 GenericTypeExpr cobj = obj as GenericTypeExpr;
1800 if (cobj == null)
1801 return false;
1802
1803 if ((type == null) || (cobj.type == null))
1804 return false;
1805
1806 return type == cobj.type;
1807 }
1808
1809 public override int GetHashCode ()
1810 {
1811 return base.GetHashCode ();
1812 }
1813 }
1814
1815 static class ConstraintChecker
1816 {
1817 /// <summary>
1818 /// Check the constraints; we're called from ResolveAsTypeTerminal()
1819 /// after fully resolving the constructed type.
1820 /// </summary>
1821 public static bool CheckAll (MemberSpec context, TypeSpec[] targs, TypeParameterSpec[] tparams, Location loc, Report report)
1822 {
1823 for (int i = 0; i < tparams.Length; i++) {
1824 if (!CheckConstraint (context, targs [i], tparams [i], loc, report))
1825 return false;
1826 }
1827
1828 return true;
1829 }
1830
1831 static bool CheckConstraint (MemberSpec context, TypeSpec atype, TypeParameterSpec tparam, Location loc, Report report)
1832 {
1833 //
1834 // First, check the `class' and `struct' constraints.
1835 //
1836 if (tparam.HasSpecialClass && !TypeManager.IsReferenceType (atype)) {
1837 report.Error (452, loc,
1838 "The type `{0}' must be a reference type in order to use it as type parameter `{1}' in the generic type or method `{2}'",
1839 TypeManager.CSharpName (atype), tparam.GetSignatureForError (), context.GetSignatureForError ());
1840 return false;
1841 }
1842
1843 if (tparam.HasSpecialStruct && (!TypeManager.IsValueType (atype) || TypeManager.IsNullableType (atype))) {
1844 report.Error (453, loc,
1845 "The type `{0}' must be a non-nullable value type in order to use it as type parameter `{1}' in the generic type or method `{2}'",
1846 TypeManager.CSharpName (atype), tparam.GetSignatureForError (), context.GetSignatureForError ());
1847 return false;
1848 }
1849
1850 //
1851 // The class constraint comes next.
1852 //
1853 if (tparam.HasTypeConstraint) {
1854 CheckConversion (context, atype, tparam, tparam.BaseType, loc, report);
1855 }
1856
1857 //
1858 // Now, check the interfaces and type parameters constraints
1859 //
1860 if (tparam.Interfaces != null) {
1861 if (TypeManager.IsNullableType (atype)) {
1862 report.Error (313, loc,
1863 "The type `{0}' cannot be used as type parameter `{1}' in the generic type or method `{2}'. The nullable type `{0}' never satisfies interface constraint",
1864 atype.GetSignatureForError (), tparam.GetSignatureForError (), context.GetSignatureForError ());
1865 } else {
1866 foreach (TypeSpec iface in tparam.Interfaces) {
1867 CheckConversion (context, atype, tparam, iface, loc, report);
1868 }
1869 }
1870 }
1871
1872 //
1873 // Finally, check the constructor constraint.
1874 //
1875 if (!tparam.HasSpecialConstructor)
1876 return true;
1877
1878 if (!HasDefaultConstructor (atype)) {
1879 report.SymbolRelatedToPreviousError (atype);
1880 report.Error (310, loc,
1881 "The type `{0}' must have a public parameterless constructor in order to use it as parameter `{1}' in the generic type or method `{2}'",
1882 TypeManager.CSharpName (atype), tparam.GetSignatureForError (), context.GetSignatureForError ());
1883 return false;
1884 }
1885
1886 return true;
1887 }
1888
1889 static void CheckConversion (MemberSpec context, TypeSpec atype, TypeParameterSpec tparam, TypeSpec ttype, Location loc, Report report)
1890 {
1891 var expr = new EmptyExpression (atype);
1892 if (!Convert.ImplicitStandardConversionExists (expr, ttype)) {
1893 report.SymbolRelatedToPreviousError (tparam);
1894 if (TypeManager.IsValueType (atype)) {
1895 report.Error (315, loc, "The type `{0}' cannot be used as type parameter `{1}' in the generic type or method `{2}'. There is no boxing conversion from `{0}' to `{3}'",
1896 atype.GetSignatureForError (), tparam.GetSignatureForError (), context.GetSignatureForError (), ttype.GetSignatureForError ());
1897 } else if (atype.IsGenericParameter) {
1898 report.Error (314, loc, "The type `{0}' cannot be used as type parameter `{1}' in the generic type or method `{2}'. There is no boxing or type parameter conversion from `{0}' to `{3}'",
1899 atype.GetSignatureForError (), tparam.GetSignatureForError (), context.GetSignatureForError (), ttype.GetSignatureForError ());
1900 } else {
1901 report.Error (311, loc, "The type `{0}' cannot be used as type parameter `{1}' in the generic type or method `{2}'. There is no implicit reference conversion from `{0}' to `{3}'",
1902 atype.GetSignatureForError (), tparam.GetSignatureForError (), context.GetSignatureForError (), ttype.GetSignatureForError ());
1903 }
1904 }
1905 }
1906
1907 static bool HasDefaultConstructor (TypeSpec atype)
1908 {
1909 var tp = atype as TypeParameterSpec;
1910 if (tp != null) {
1911 return tp.HasSpecialConstructor || tp.HasSpecialStruct;
1912 }
1913
1914 if (atype.IsStruct || atype.IsEnum)
1915 return true;
1916
1917 if (atype.IsAbstract)
1918 return false;
1919
1920 var tdef = atype.GetDefinition ();
1921
1922 //
1923 // In some circumstances MemberCache is not yet populated and members
1924 // cannot be defined yet (recursive type new constraints)
1925 //
1926 // class A<T> where T : B<T>, new () {}
1927 // class B<T> where T : A<T>, new () {}
1928 //
1929 var tc = tdef.MemberDefinition as Class;
1930 if (tc != null) {
1931 if (tc.InstanceConstructors == null) {
1932 // Default ctor will be generated later
1933 return true;
1934 }
1935
1936 foreach (var c in tc.InstanceConstructors) {
1937 if (c.ParameterInfo.IsEmpty) {
1938 if ((c.ModFlags & Modifiers.PUBLIC) != 0)
1939 return true;
1940 }
1941 }
1942
1943 return false;
1944 }
1945
1946 var found = MemberCache.FindMember (tdef,
1947 MemberFilter.Constructor (ParametersCompiled.EmptyReadOnlyParameters),
1948 BindingRestriction.DeclaredOnly | BindingRestriction.InstanceOnly);
1949
1950 return found != null && (found.Modifiers & Modifiers.PUBLIC) != 0;
1951 }
1952 }
1953
1954 /// <summary>
1955 /// A generic method definition.
1956 /// </summary>
1957 public class GenericMethod : DeclSpace
1958 {
1959 ParametersCompiled parameters;
1960
1961 public GenericMethod (NamespaceEntry ns, DeclSpace parent, MemberName name,
1962 FullNamedExpression return_type, ParametersCompiled parameters)
1963 : base (ns, parent, name, null)
1964 {
1965 this.parameters = parameters;
1966 }
1967
1968 public GenericMethod (NamespaceEntry ns, DeclSpace parent, MemberName name, TypeParameter[] tparams,
1969 FullNamedExpression return_type, ParametersCompiled parameters)
1970 : this (ns, parent, name, return_type, parameters)
1971 {
1972 this.type_params = tparams;
1973 }
1974
1975 public override TypeParameter[] CurrentTypeParameters {
1976 get {
1977 return base.type_params;
1978 }
1979 }
1980
1981 public override TypeBuilder DefineType ()
1982 {
1983 throw new Exception ();
1984 }
1985
1986 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
1987 {
1988 throw new NotSupportedException ();
1989 }
1990
1991 public override bool Define ()
1992 {
1993 throw new NotSupportedException ();
1994 }
1995
1996 /// <summary>
1997 /// Define and resolve the type parameters.
1998 /// We're called from Method.Define().
1999 /// </summary>
2000 public bool Define (MethodOrOperator m)
2001 {
2002 TypeParameterName[] names = MemberName.TypeArguments.GetDeclarations ();
2003 string[] snames = new string [names.Length];
2004 for (int i = 0; i < names.Length; i++) {
2005 string type_argument_name = names[i].Name;
2006 int idx = parameters.GetParameterIndexByName (type_argument_name);
2007
2008 if (idx >= 0) {
2009 var b = m.Block;
2010 if (b == null)
2011 b = new ToplevelBlock (Compiler, Location);
2012
2013 b.Error_AlreadyDeclaredTypeParameter (parameters [i].Location,
2014 type_argument_name, "method parameter");
2015 }
2016
2017 if (m.Block != null) {
2018 var ikv = m.Block.GetKnownVariable (type_argument_name);
2019 if (ikv != null)
2020 ikv.Block.Error_AlreadyDeclaredTypeParameter (ikv.Location, type_argument_name, "local variable");
2021 }
2022
2023 snames[i] = type_argument_name;
2024 }
2025
2026 GenericTypeParameterBuilder[] gen_params = m.MethodBuilder.DefineGenericParameters (snames);
2027 for (int i = 0; i < TypeParameters.Length; i++)
2028 TypeParameters [i].Define (gen_params [i], null);
2029
2030 return true;
2031 }
2032
2033 public void EmitAttributes ()
2034 {
2035 if (OptAttributes != null)
2036 OptAttributes.Emit ();
2037 }
2038
2039 public override string GetSignatureForError ()
2040 {
2041 return base.GetSignatureForError () + parameters.GetSignatureForError ();
2042 }
2043
2044 public override AttributeTargets AttributeTargets {
2045 get {
2046 return AttributeTargets.Method | AttributeTargets.ReturnValue;
2047 }
2048 }
2049
2050 public override string DocCommentHeader {
2051 get { return "M:"; }
2052 }
2053
2054 public new void VerifyClsCompliance ()
2055 {
2056 foreach (TypeParameter tp in TypeParameters) {
2057 tp.VerifyClsCompliance ();
2058 }
2059 }
2060 }
2061
2062 public partial class TypeManager
2063 {
2064 public static Variance CheckTypeVariance (TypeSpec t, Variance expected, IMemberContext member)
2065 {
2066 var tp = t as TypeParameterSpec;
2067 if (tp != null) {
2068 Variance v = tp.Variance;
2069 if (expected == Variance.None && v != expected ||
2070 expected == Variance.Covariant && v == Variance.Contravariant ||
2071 expected == Variance.Contravariant && v == Variance.Covariant) {
2072 ((TypeParameter)tp.MemberDefinition).ErrorInvalidVariance (member, expected);
2073 }
2074
2075 return expected;
2076 }
2077
2078 if (t.TypeArguments.Length > 0) {
2079 var targs_definition = t.MemberDefinition.TypeParameters;
2080 TypeSpec[] targs = GetTypeArguments (t);
2081 for (int i = 0; i < targs.Length; ++i) {
2082 Variance v = targs_definition[i].Variance;
2083 CheckTypeVariance (targs[i], (Variance) ((int)v * (int)expected), member);
2084 }
2085
2086 return expected;
2087 }
2088
2089 if (t.IsArray)
2090 return CheckTypeVariance (GetElementType (t), expected, member);
2091
2092 return Variance.None;
2093 }
2094
2095 /// <summary>
2096 /// Type inference. Try to infer the type arguments from `method',
2097 /// which is invoked with the arguments `arguments'. This is used
2098 /// when resolving an Invocation or a DelegateInvocation and the user
2099 /// did not explicitly specify type arguments.
2100 /// </summary>
2101 public static int InferTypeArguments (ResolveContext ec, Arguments arguments, ref MethodSpec method)
2102 {
2103 ATypeInference ti = ATypeInference.CreateInstance (arguments);
2104 TypeSpec[] i_args = ti.InferMethodArguments (ec, method);
2105 if (i_args == null)
2106 return ti.InferenceScore;
2107
2108 if (i_args.Length == 0)
2109 return 0;
2110
2111 method = method.MakeGenericMethod (i_args);
2112 return 0;
2113 }
2114 }
2115
2116 abstract class ATypeInference
2117 {
2118 protected readonly Arguments arguments;
2119 protected readonly int arg_count;
2120
2121 protected ATypeInference (Arguments arguments)
2122 {
2123 this.arguments = arguments;
2124 if (arguments != null)
2125 arg_count = arguments.Count;
2126 }
2127
2128 public static ATypeInference CreateInstance (Arguments arguments)
2129 {
2130 return new TypeInference (arguments);
2131 }
2132
2133 public virtual int InferenceScore {
2134 get {
2135 return int.MaxValue;
2136 }
2137 }
2138
2139 public abstract TypeSpec[] InferMethodArguments (ResolveContext ec, MethodSpec method);
2140 }
2141
2142 //
2143 // Implements C# type inference
2144 //
2145 class TypeInference : ATypeInference
2146 {
2147 //
2148 // Tracks successful rate of type inference
2149 //
2150 int score = int.MaxValue;
2151
2152 public TypeInference (Arguments arguments)
2153 : base (arguments)
2154 {
2155 }
2156
2157 public override int InferenceScore {
2158 get {
2159 return score;
2160 }
2161 }
2162
2163 public override TypeSpec[] InferMethodArguments (ResolveContext ec, MethodSpec method)
2164 {
2165 var method_generic_args = method.GenericDefinition.TypeParameters;
2166 TypeInferenceContext context = new TypeInferenceContext (method_generic_args);
2167 if (!context.UnfixedVariableExists)
2168 return TypeSpec.EmptyTypes;
2169
2170 AParametersCollection pd = method.Parameters;
2171 if (!InferInPhases (ec, context, pd))
2172 return null;
2173
2174 return context.InferredTypeArguments;
2175 }
2176
2177 //
2178 // Implements method type arguments inference
2179 //
2180 bool InferInPhases (ResolveContext ec, TypeInferenceContext tic, AParametersCollection methodParameters)
2181 {
2182 int params_arguments_start;
2183 if (methodParameters.HasParams) {
2184 params_arguments_start = methodParameters.Count - 1;
2185 } else {
2186 params_arguments_start = arg_count;
2187 }
2188
2189 TypeSpec [] ptypes = methodParameters.Types;
2190
2191 //
2192 // The first inference phase
2193 //
2194 TypeSpec method_parameter = null;
2195 for (int i = 0; i < arg_count; i++) {
2196 Argument a = arguments [i];
2197 if (a == null)
2198 continue;
2199
2200 if (i < params_arguments_start) {
2201 method_parameter = methodParameters.Types [i];
2202 } else if (i == params_arguments_start) {
2203 if (arg_count == params_arguments_start + 1 && TypeManager.HasElementType (a.Type))
2204 method_parameter = methodParameters.Types [params_arguments_start];
2205 else
2206 method_parameter = TypeManager.GetElementType (methodParameters.Types [params_arguments_start]);
2207
2208 ptypes = (TypeSpec[]) ptypes.Clone ();
2209 ptypes [i] = method_parameter;
2210 }
2211
2212 //
2213 // When a lambda expression, an anonymous method
2214 // is used an explicit argument type inference takes a place
2215 //
2216 AnonymousMethodExpression am = a.Expr as AnonymousMethodExpression;
2217 if (am != null) {
2218 if (am.ExplicitTypeInference (ec, tic, method_parameter))
2219 --score;
2220 continue;
2221 }
2222
2223 if (a.IsByRef) {
2224 score -= tic.ExactInference (a.Type, method_parameter);
2225 continue;
2226 }
2227
2228 if (a.Expr.Type == InternalType.Null)
2229 continue;
2230
2231 if (TypeManager.IsValueType (method_parameter)) {
2232 score -= tic.LowerBoundInference (a.Type, method_parameter);
2233 continue;
2234 }
2235
2236 //
2237 // Otherwise an output type inference is made
2238 //
2239 score -= tic.OutputTypeInference (ec, a.Expr, method_parameter);
2240 }
2241
2242 //
2243 // Part of the second phase but because it happens only once
2244 // we don't need to call it in cycle
2245 //
2246 bool fixed_any = false;
2247 if (!tic.FixIndependentTypeArguments (ec, ptypes, ref fixed_any))
2248 return false;
2249
2250 return DoSecondPhase (ec, tic, ptypes, !fixed_any);
2251 }
2252
2253 bool DoSecondPhase (ResolveContext ec, TypeInferenceContext tic, TypeSpec[] methodParameters, bool fixDependent)
2254 {
2255 bool fixed_any = false;
2256 if (fixDependent && !tic.FixDependentTypes (ec, ref fixed_any))
2257 return false;
2258
2259 // If no further unfixed type variables exist, type inference succeeds
2260 if (!tic.UnfixedVariableExists)
2261 return true;
2262
2263 if (!fixed_any && fixDependent)
2264 return false;
2265
2266 // For all arguments where the corresponding argument output types
2267 // contain unfixed type variables but the input types do not,
2268 // an output type inference is made
2269 for (int i = 0; i < arg_count; i++) {
2270
2271 // Align params arguments
2272 TypeSpec t_i = methodParameters [i >= methodParameters.Length ? methodParameters.Length - 1: i];
2273
2274 if (!TypeManager.IsDelegateType (t_i)) {
2275 if (t_i.GetDefinition () != TypeManager.expression_type)
2276 continue;
2277
2278 t_i = TypeManager.GetTypeArguments (t_i) [0];
2279 }
2280
2281 var mi = Delegate.GetInvokeMethod (ec.Compiler, t_i);
2282 TypeSpec rtype = mi.ReturnType;
2283
2284 if (tic.IsReturnTypeNonDependent (ec, mi, rtype))
2285 score -= tic.OutputTypeInference (ec, arguments [i].Expr, t_i);
2286 }
2287
2288
2289 return DoSecondPhase (ec, tic, methodParameters, true);
2290 }
2291 }
2292
2293 public class TypeInferenceContext
2294 {
2295 enum BoundKind
2296 {
2297 Exact = 0,
2298 Lower = 1,
2299 Upper = 2
2300 }
2301
2302 class BoundInfo
2303 {
2304 public readonly TypeSpec Type;
2305 public readonly BoundKind Kind;
2306
2307 public BoundInfo (TypeSpec type, BoundKind kind)
2308 {
2309 this.Type = type;
2310 this.Kind = kind;
2311 }
2312
2313 public override int GetHashCode ()
2314 {
2315 return Type.GetHashCode ();
2316 }
2317
2318 public override bool Equals (object obj)
2319 {
2320 BoundInfo a = (BoundInfo) obj;
2321 return Type == a.Type && Kind == a.Kind;
2322 }
2323 }
2324
2325 readonly TypeSpec[] unfixed_types;
2326 readonly TypeSpec[] fixed_types;
2327 readonly List<BoundInfo>[] bounds;
2328 bool failed;
2329
2330 // TODO MemberCache: Could it be TypeParameterSpec[] ??
2331 public TypeInferenceContext (TypeSpec[] typeArguments)
2332 {
2333 if (typeArguments.Length == 0)
2334 throw new ArgumentException ("Empty generic arguments");
2335
2336 fixed_types = new TypeSpec [typeArguments.Length];
2337 for (int i = 0; i < typeArguments.Length; ++i) {
2338 if (typeArguments [i].IsGenericParameter) {
2339 if (bounds == null) {
2340 bounds = new List<BoundInfo> [typeArguments.Length];
2341 unfixed_types = new TypeSpec [typeArguments.Length];
2342 }
2343 unfixed_types [i] = typeArguments [i];
2344 } else {
2345 fixed_types [i] = typeArguments [i];
2346 }
2347 }
2348 }
2349
2350 //
2351 // Used together with AddCommonTypeBound fo implement
2352 // 7.4.2.13 Finding the best common type of a set of expressions
2353 //
2354 public TypeInferenceContext ()
2355 {
2356 fixed_types = new TypeSpec [1];
2357 unfixed_types = new TypeSpec [1];
2358 unfixed_types[0] = InternalType.Arglist; // it can be any internal type
2359 bounds = new List<BoundInfo> [1];
2360 }
2361
2362 public TypeSpec[] InferredTypeArguments {
2363 get {
2364 return fixed_types;
2365 }
2366 }
2367
2368 public void AddCommonTypeBound (TypeSpec type)
2369 {
2370 AddToBounds (new BoundInfo (type, BoundKind.Lower), 0);
2371 }
2372
2373 void AddToBounds (BoundInfo bound, int index)
2374 {
2375 //
2376 // Some types cannot be used as type arguments
2377 //
2378 if (bound.Type == TypeManager.void_type || bound.Type.IsPointer)
2379 return;
2380
2381 var a = bounds [index];
2382 if (a == null) {
2383 a = new List<BoundInfo> ();
2384 bounds [index] = a;
2385 } else {
2386 if (a.Contains (bound))
2387 return;
2388 }
2389
2390 //
2391 // SPEC: does not cover type inference using constraints
2392 //
2393 //if (TypeManager.IsGenericParameter (t)) {
2394 // GenericConstraints constraints = TypeManager.GetTypeParameterConstraints (t);
2395 // if (constraints != null) {
2396 // //if (constraints.EffectiveBaseClass != null)
2397 // // t = constraints.EffectiveBaseClass;
2398 // }
2399 //}
2400 a.Add (bound);
2401 }
2402
2403 bool AllTypesAreFixed (TypeSpec[] types)
2404 {
2405 foreach (TypeSpec t in types) {
2406 if (t.IsGenericParameter) {
2407 if (!IsFixed (t))
2408 return false;
2409 continue;
2410 }
2411
2412 if (TypeManager.IsGenericType (t))
2413 return AllTypesAreFixed (TypeManager.GetTypeArguments (t));
2414 }
2415
2416 return true;
2417 }
2418
2419 //
2420 // 26.3.3.8 Exact Inference
2421 //
2422 public int ExactInference (TypeSpec u, TypeSpec v)
2423 {
2424 // If V is an array type
2425 if (v.IsArray) {
2426 if (!u.IsArray)
2427 return 0;
2428
2429 // TODO MemberCache: GetMetaInfo ()
2430 if (u.GetMetaInfo ().GetArrayRank () != v.GetMetaInfo ().GetArrayRank ())
2431 return 0;
2432
2433 return ExactInference (TypeManager.GetElementType (u), TypeManager.GetElementType (v));
2434 }
2435
2436 // If V is constructed type and U is constructed type
2437 if (TypeManager.IsGenericType (v)) {
2438 if (!TypeManager.IsGenericType (u))
2439 return 0;
2440
2441 TypeSpec [] ga_u = TypeManager.GetTypeArguments (u);
2442 TypeSpec [] ga_v = TypeManager.GetTypeArguments (v);
2443 if (ga_u.Length != ga_v.Length)
2444 return 0;
2445
2446 int score = 0;
2447 for (int i = 0; i < ga_u.Length; ++i)
2448 score += ExactInference (ga_u [i], ga_v [i]);
2449
2450 return score > 0 ? 1 : 0;
2451 }
2452
2453 // If V is one of the unfixed type arguments
2454 int pos = IsUnfixed (v);
2455 if (pos == -1)
2456 return 0;
2457
2458 AddToBounds (new BoundInfo (u, BoundKind.Exact), pos);
2459 return 1;
2460 }
2461
2462 public bool FixAllTypes (ResolveContext ec)
2463 {
2464 for (int i = 0; i < unfixed_types.Length; ++i) {
2465 if (!FixType (ec, i))
2466 return false;
2467 }
2468 return true;
2469 }
2470
2471 //
2472 // All unfixed type variables Xi are fixed for which all of the following hold:
2473 // a, There is at least one type variable Xj that depends on Xi
2474 // b, Xi has a non-empty set of bounds
2475 //
2476 public bool FixDependentTypes (ResolveContext ec, ref bool fixed_any)
2477 {
2478 for (int i = 0; i < unfixed_types.Length; ++i) {
2479 if (unfixed_types[i] == null)
2480 continue;
2481
2482 if (bounds[i] == null)
2483 continue;
2484
2485 if (!FixType (ec, i))
2486 return false;
2487
2488 fixed_any = true;
2489 }
2490
2491 return true;
2492 }
2493
2494 //
2495 // All unfixed type variables Xi which depend on no Xj are fixed
2496 //
2497 public bool FixIndependentTypeArguments (ResolveContext ec, TypeSpec[] methodParameters, ref bool fixed_any)
2498 {
2499 var types_to_fix = new List<TypeSpec> (unfixed_types);
2500 for (int i = 0; i < methodParameters.Length; ++i) {
2501 TypeSpec t = methodParameters[i];
2502
2503 if (!TypeManager.IsDelegateType (t)) {
2504 if (TypeManager.expression_type == null || t.MemberDefinition != TypeManager.expression_type.MemberDefinition)
2505 continue;
2506
2507 t = TypeManager.GetTypeArguments (t) [0];
2508 }
2509
2510 if (t.IsGenericParameter)
2511 continue;
2512
2513 var invoke = Delegate.GetInvokeMethod (ec.Compiler, t);
2514 TypeSpec rtype = invoke.ReturnType;
2515 if (!rtype.IsGenericParameter && !TypeManager.IsGenericType (rtype))
2516 continue;
2517
2518 // Remove dependent types, they cannot be fixed yet
2519 RemoveDependentTypes (types_to_fix, rtype);
2520 }
2521
2522 foreach (TypeSpec t in types_to_fix) {
2523 if (t == null)
2524 continue;
2525
2526 int idx = IsUnfixed (t);
2527 if (idx >= 0 && !FixType (ec, idx)) {
2528 return false;
2529 }
2530 }
2531
2532 fixed_any = types_to_fix.Count > 0;
2533 return true;
2534 }
2535
2536 //
2537 // 26.3.3.10 Fixing
2538 //
2539 public bool FixType (ResolveContext ec, int i)
2540 {
2541 // It's already fixed
2542 if (unfixed_types[i] == null)
2543 throw new InternalErrorException ("Type argument has been already fixed");
2544
2545 if (failed)
2546 return false;
2547
2548 var candidates = bounds [i];
2549 if (candidates == null)
2550 return false;
2551
2552 if (candidates.Count == 1) {
2553 unfixed_types[i] = null;
2554 TypeSpec t = candidates[0].Type;
2555 if (t == InternalType.Null)
2556 return false;
2557
2558 fixed_types [i] = t;
2559 return true;
2560 }
2561
2562 //
2563 // Determines a unique type from which there is
2564 // a standard implicit conversion to all the other
2565 // candidate types.
2566 //
2567 TypeSpec best_candidate = null;
2568 int cii;
2569 int candidates_count = candidates.Count;
2570 for (int ci = 0; ci < candidates_count; ++ci) {
2571 BoundInfo bound = candidates [ci];
2572 for (cii = 0; cii < candidates_count; ++cii) {
2573 if (cii == ci)
2574 continue;
2575
2576 BoundInfo cbound = candidates[cii];
2577
2578 // Same type parameters with different bounds
2579 if (cbound.Type == bound.Type) {
2580 if (bound.Kind != BoundKind.Exact)
2581 bound = cbound;
2582
2583 continue;
2584 }
2585
2586 if (bound.Kind == BoundKind.Exact || cbound.Kind == BoundKind.Exact) {
2587 if (cbound.Kind != BoundKind.Exact) {
2588 if (!Convert.ImplicitConversionExists (ec, new TypeExpression (cbound.Type, Location.Null), bound.Type)) {
2589 break;
2590 }
2591
2592 continue;
2593 }
2594
2595 if (bound.Kind != BoundKind.Exact) {
2596 if (!Convert.ImplicitConversionExists (ec, new TypeExpression (bound.Type, Location.Null), cbound.Type)) {
2597 break;
2598 }
2599
2600 bound = cbound;
2601 continue;
2602 }
2603
2604 break;
2605 }
2606
2607 if (bound.Kind == BoundKind.Lower) {
2608 if (!Convert.ImplicitConversionExists (ec, new TypeExpression (cbound.Type, Location.Null), bound.Type)) {
2609 break;
2610 }
2611 } else {
2612 if (!Convert.ImplicitConversionExists (ec, new TypeExpression (bound.Type, Location.Null), cbound.Type)) {
2613 break;
2614 }
2615 }
2616 }
2617
2618 if (cii != candidates_count)
2619 continue;
2620
2621 if (best_candidate != null && best_candidate != bound.Type)
2622 return false;
2623
2624 best_candidate = bound.Type;
2625 }
2626
2627 if (best_candidate == null)
2628 return false;
2629
2630 unfixed_types[i] = null;
2631 fixed_types[i] = best_candidate;
2632 return true;
2633 }
2634
2635 //
2636 // Uses inferred or partially infered types to inflate delegate type argument. Returns
2637 // null when type parameter was not yet inferres
2638 //
2639 public TypeSpec InflateGenericArgument (TypeSpec parameter)
2640 {
2641 var tp = parameter as TypeParameterSpec;
2642 if (tp != null) {
2643 //
2644 // Type inference work on generic arguments (MVAR) only
2645 //
2646 if (!tp.IsMethodOwned)
2647 return parameter;
2648
2649 return fixed_types [tp.DeclaredPosition] ?? parameter;
2650 }
2651
2652 var gt = parameter as InflatedTypeSpec;
2653 if (gt != null) {
2654 var inflated_targs = new TypeSpec [gt.TypeArguments.Length];
2655 for (int ii = 0; ii < inflated_targs.Length; ++ii) {
2656 var inflated = InflateGenericArgument (gt.TypeArguments [ii]);
2657 if (inflated == null)
2658 return null;
2659
2660 inflated_targs[ii] = inflated;
2661 }
2662
2663 return gt.GetDefinition ().MakeGenericType (inflated_targs);
2664 }
2665
2666 return parameter;
2667 }
2668
2669 //
2670 // Tests whether all delegate input arguments are fixed and generic output type
2671 // requires output type inference
2672 //
2673 public bool IsReturnTypeNonDependent (ResolveContext ec, MethodSpec invoke, TypeSpec returnType)
2674 {
2675 if (returnType.IsGenericParameter) {
2676 if (IsFixed (returnType))
2677 return false;
2678 } else if (TypeManager.IsGenericType (returnType)) {
2679 if (TypeManager.IsDelegateType (returnType)) {
2680 invoke = Delegate.GetInvokeMethod (ec.Compiler, returnType);
2681 return IsReturnTypeNonDependent (ec, invoke, invoke.ReturnType);
2682 }
2683
2684 TypeSpec[] g_args = TypeManager.GetTypeArguments (returnType);
2685
2686 // At least one unfixed return type has to exist
2687 if (AllTypesAreFixed (g_args))
2688 return false;
2689 } else {
2690 return false;
2691 }
2692
2693 // All generic input arguments have to be fixed
2694 AParametersCollection d_parameters = invoke.Parameters;
2695 return AllTypesAreFixed (d_parameters.Types);
2696 }
2697
2698 bool IsFixed (TypeSpec type)
2699 {
2700 return IsUnfixed (type) == -1;
2701 }
2702
2703 int IsUnfixed (TypeSpec type)
2704 {
2705 if (!type.IsGenericParameter)
2706 return -1;
2707
2708 //return unfixed_types[type.GenericParameterPosition] != null;
2709 for (int i = 0; i < unfixed_types.Length; ++i) {
2710 if (unfixed_types [i] == type)
2711 return i;
2712 }
2713
2714 return -1;
2715 }
2716
2717 //
2718 // 26.3.3.9 Lower-bound Inference
2719 //
2720 public int LowerBoundInference (TypeSpec u, TypeSpec v)
2721 {
2722 return LowerBoundInference (u, v, false);
2723 }
2724
2725 //
2726 // Lower-bound (false) or Upper-bound (true) inference based on inversed argument
2727 //
2728 int LowerBoundInference (TypeSpec u, TypeSpec v, bool inversed)
2729 {
2730 // If V is one of the unfixed type arguments
2731 int pos = IsUnfixed (v);
2732 if (pos != -1) {
2733 AddToBounds (new BoundInfo (u, inversed ? BoundKind.Upper : BoundKind.Lower), pos);
2734 return 1;
2735 }
2736
2737 // If U is an array type
2738 var u_ac = u as ArrayContainer;
2739 if (u_ac != null) {
2740 var v_ac = v as ArrayContainer;
2741 if (v_ac != null) {
2742 if (u_ac.Rank != v_ac.Rank)
2743 return 0;
2744
2745 if (TypeManager.IsValueType (u_ac.Element))
2746 return ExactInference (u_ac.Element, v_ac.Element);
2747
2748 return LowerBoundInference (u_ac.Element, v_ac.Element, inversed);
2749 }
2750
2751 if (u_ac.Rank != 1)
2752 return 0;
2753
2754 if (TypeManager.IsGenericType (v)) {
2755 TypeSpec g_v = v.GetDefinition ();
2756 if (g_v != TypeManager.generic_ilist_type &&
2757 g_v != TypeManager.generic_icollection_type &&
2758 g_v != TypeManager.generic_ienumerable_type)
2759 return 0;
2760
2761 var v_i = TypeManager.GetTypeArguments (v) [0];
2762 if (TypeManager.IsValueType (u_ac.Element))
2763 return ExactInference (u_ac.Element, v_i);
2764
2765 return LowerBoundInference (u_ac.Element, v_i);
2766 }
2767 } else if (TypeManager.IsGenericType (v)) {
2768 //
2769 // if V is a constructed type C<V1..Vk> and there is a unique type C<U1..Uk>
2770 // such that U is identical to, inherits from (directly or indirectly),
2771 // or implements (directly or indirectly) C<U1..Uk>
2772 //
2773 var u_candidates = new List<TypeSpec> ();
2774 var open_v = v.MemberDefinition;
2775
2776 for (TypeSpec t = u; t != null; t = t.BaseType) {
2777 if (open_v == t.MemberDefinition)
2778 u_candidates.Add (t);
2779
2780 if (t.Interfaces != null) {
2781 foreach (var iface in t.Interfaces) {
2782 if (open_v == iface.MemberDefinition)
2783 u_candidates.Add (iface);
2784 }
2785 }
2786 }
2787
2788 TypeSpec [] unique_candidate_targs = null;
2789 TypeSpec[] ga_v = TypeManager.GetTypeArguments (v);
2790 foreach (TypeSpec u_candidate in u_candidates) {
2791 //
2792 // The unique set of types U1..Uk means that if we have an interface I<T>,
2793 // class U : I<int>, I<long> then no type inference is made when inferring
2794 // type I<T> by applying type U because T could be int or long
2795 //
2796 if (unique_candidate_targs != null) {
2797 TypeSpec[] second_unique_candidate_targs = TypeManager.GetTypeArguments (u_candidate);
2798 if (TypeSpecComparer.Default.Equals (unique_candidate_targs, second_unique_candidate_targs)) {
2799 unique_candidate_targs = second_unique_candidate_targs;
2800 continue;
2801 }
2802
2803 //
2804 // This should always cause type inference failure
2805 //
2806 failed = true;
2807 return 1;
2808 }
2809
2810 unique_candidate_targs = TypeManager.GetTypeArguments (u_candidate);
2811 }
2812
2813 if (unique_candidate_targs != null) {
2814 var ga_open_v = open_v.TypeParameters;
2815 int score = 0;
2816 for (int i = 0; i < unique_candidate_targs.Length; ++i) {
2817 Variance variance = ga_open_v [i].Variance;
2818
2819 TypeSpec u_i = unique_candidate_targs [i];
2820 if (variance == Variance.None || TypeManager.IsValueType (u_i)) {
2821 if (ExactInference (u_i, ga_v [i]) == 0)
2822 ++score;
2823 } else {
2824 bool upper_bound = (variance == Variance.Contravariant && !inversed) ||
2825 (variance == Variance.Covariant && inversed);
2826
2827 if (LowerBoundInference (u_i, ga_v [i], upper_bound) == 0)
2828 ++score;
2829 }
2830 }
2831 return score;
2832 }
2833 }
2834
2835 return 0;
2836 }
2837
2838 //
2839 // 26.3.3.6 Output Type Inference
2840 //
2841 public int OutputTypeInference (ResolveContext ec, Expression e, TypeSpec t)
2842 {
2843 // If e is a lambda or anonymous method with inferred return type
2844 AnonymousMethodExpression ame = e as AnonymousMethodExpression;
2845 if (ame != null) {
2846 TypeSpec rt = ame.InferReturnType (ec, this, t);
2847 var invoke = Delegate.GetInvokeMethod (ec.Compiler, t);
2848
2849 if (rt == null) {
2850 AParametersCollection pd = invoke.Parameters;
2851 return ame.Parameters.Count == pd.Count ? 1 : 0;
2852 }
2853
2854 TypeSpec rtype = invoke.ReturnType;
2855 return LowerBoundInference (rt, rtype) + 1;
2856 }
2857
2858 //
2859 // if E is a method group and T is a delegate type or expression tree type
2860 // return type Tb with parameter types T1..Tk and return type Tb, and overload
2861 // resolution of E with the types T1..Tk yields a single method with return type U,
2862 // then a lower-bound inference is made from U for Tb.
2863 //
2864 if (e is MethodGroupExpr) {
2865 if (!TypeManager.IsDelegateType (t)) {
2866 if (TypeManager.expression_type == null || t.MemberDefinition != TypeManager.expression_type.MemberDefinition)
2867 return 0;
2868
2869 t = TypeManager.GetTypeArguments (t)[0];
2870 }
2871
2872 var invoke = Delegate.GetInvokeMethod (ec.Compiler, t);
2873 TypeSpec rtype = invoke.ReturnType;
2874
2875 if (!rtype.IsGenericParameter && !TypeManager.IsGenericType (rtype))
2876 return 0;
2877
2878 // LAMESPEC: Standard does not specify that all methodgroup arguments
2879 // has to be fixed but it does not specify how to do recursive type inference
2880 // either. We choose the simple option and infer return type only
2881 // if all delegate generic arguments are fixed.
2882 TypeSpec[] param_types = new TypeSpec [invoke.Parameters.Count];
2883 for (int i = 0; i < param_types.Length; ++i) {
2884 var inflated = InflateGenericArgument (invoke.Parameters.Types[i]);
2885 if (inflated == null)
2886 return 0;
2887
2888 param_types[i] = inflated;
2889 }
2890
2891 MethodGroupExpr mg = (MethodGroupExpr) e;
2892 Arguments args = DelegateCreation.CreateDelegateMethodArguments (invoke.Parameters, param_types, e.Location);
2893 mg = mg.OverloadResolve (ec, ref args, true, e.Location);
2894 if (mg == null)
2895 return 0;
2896
2897 return LowerBoundInference (mg.BestCandidate.ReturnType, rtype) + 1;
2898 }
2899
2900 //
2901 // if e is an expression with type U, then
2902 // a lower-bound inference is made from U for T
2903 //
2904 return LowerBoundInference (e.Type, t) * 2;
2905 }
2906
2907 void RemoveDependentTypes (List<TypeSpec> types, TypeSpec returnType)
2908 {
2909 int idx = IsUnfixed (returnType);
2910 if (idx >= 0) {
2911 types [idx] = null;
2912 return;
2913 }
2914
2915 if (TypeManager.IsGenericType (returnType)) {
2916 foreach (TypeSpec t in TypeManager.GetTypeArguments (returnType)) {
2917 RemoveDependentTypes (types, t);
2918 }
2919 }
2920 }
2921
2922 public bool UnfixedVariableExists {
2923 get {
2924 if (unfixed_types == null)
2925 return false;
2926
2927 foreach (TypeSpec ut in unfixed_types)
2928 if (ut != null)
2929 return true;
2930 return false;
2931 }
2932 }
2933 }
2934 }
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