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2010-05-25 Jb Evain <jbevain@novell.com>
[mcs.git] / mcs / generic.cs
blob00c6930d17f08497acee0d132163a4328227f2d6
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 (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 override MemberSpec InflateMember (TypeParameterInflator inflator)
947 {
948 var tps = (TypeParameterSpec) MemberwiseClone ();
949 tps.BaseType = inflator.Inflate (BaseType);
950 if (ifaces != null) {
951 tps.ifaces = new TypeSpec[ifaces.Count];
952 for (int i = 0; i < ifaces.Count; ++i)
953 tps.ifaces[i] = inflator.Inflate (ifaces[i]);
954 }
955 if (targs != null) {
956 tps.targs = new TypeSpec[targs.Length];
957 for (int i = 0; i < targs.Length; ++i)
958 tps.targs[i] = inflator.Inflate (targs[i]);
959 }
960
961 return tps;
962 }
963
964 //
965 // Populates type parameter members using type parameter constraints
966 // The trick here is to be called late enough but not too late to
967 // populate member cache with all members from other types
968 //
969 protected override void InitializeMemberCache (bool onlyTypes)
970 {
971 cache = new MemberCache ();
972 if (ifaces != null) {
973 foreach (var iface_type in Interfaces) {
974 cache.AddInterface (iface_type);
975 }
976 }
977 }
978
979 public override TypeSpec Mutate (TypeParameterMutator mutator)
980 {
981 return mutator.Mutate (this);
982 }
983 }
984
985 public struct TypeParameterInflator
986 {
987 readonly TypeSpec type;
988 readonly TypeParameterSpec[] tparams;
989 readonly TypeSpec[] targs;
990
991 public TypeParameterInflator (TypeParameterInflator nested, TypeSpec type)
992 : this (type, nested.tparams, nested.targs)
993 {
994 }
995
996 public TypeParameterInflator (TypeSpec type, TypeParameterSpec[] tparams, TypeSpec[] targs)
997 {
998 if (tparams.Length != targs.Length)
999 throw new ArgumentException ("Invalid arguments");
1000
1001 this.tparams = tparams;
1002 this.targs = targs;
1003 this.type = type;
1004 }
1005
1006 //
1007 // Type parameters to inflate
1008 //
1009 public TypeParameterSpec[] TypeParameters {
1010 get {
1011 return tparams;
1012 }
1013 }
1014
1015 public TypeSpec Inflate (TypeSpec ts)
1016 {
1017 var tp = ts as TypeParameterSpec;
1018 if (tp != null)
1019 return Inflate (tp);
1020
1021 var ac = ts as ArrayContainer;
1022 if (ac != null) {
1023 var et = Inflate (ac.Element);
1024 if (et != ac.Element)
1025 return ArrayContainer.MakeType (et, ac.Rank);
1026
1027 return ac;
1028 }
1029
1030 //
1031 // When inflating a nested type, inflate its parent first
1032 // in case it's using same type parameters (was inflated within the type)
1033 //
1034 if (ts.IsNested) {
1035 var parent = Inflate (ts.DeclaringType);
1036 if (ts.DeclaringType != parent) {
1037 //
1038 // Keep the inflated type arguments
1039 //
1040 var targs = ts.TypeArguments;
1041
1042 //
1043 // Parent was inflated, find the same type on inflated type
1044 // to use same cache for nested types on same generic parent
1045 //
1046 // TODO: Should use BindingRestriction.DeclaredOnly or GetMember
1047 ts = MemberCache.FindNestedType (parent, ts.Name, targs.Length);
1048
1049 //
1050 // Handle the tricky case where parent shares local type arguments
1051 // which means inflating inflated type
1052 //
1053 // class Test<T> {
1054 // public static Nested<T> Foo () { return null; }
1055 //
1056 // public class Nested<U> {}
1057 // }
1058 //
1059 // return type of Test<string>.Foo() has to be Test<string>.Nested<string>
1060 //
1061 if (targs.Length > 0) {
1062 var inflated_targs = new TypeSpec [targs.Length];
1063 for (var i = 0; i < targs.Length; ++i)
1064 inflated_targs[i] = Inflate (targs[i]);
1065
1066 ts = ts.MakeGenericType (inflated_targs);
1067 }
1068
1069 return ts;
1070 }
1071 }
1072
1073 // Inflate generic type
1074 if (ts.Arity > 0)
1075 return InflateTypeParameters (ts);
1076
1077 return ts;
1078 }
1079
1080 public TypeSpec Inflate (TypeParameterSpec tp)
1081 {
1082 for (int i = 0; i < tparams.Length; ++i)
1083 if (tparams [i] == tp)
1084 return targs[i];
1085
1086 // CECIL: This can happen when inflating nested types
1087 // without type arguments specified
1088 return tp;
1089 }
1090
1091 //
1092 // Inflates generic types
1093 //
1094 TypeSpec InflateTypeParameters (TypeSpec type)
1095 {
1096 var targs = new TypeSpec[type.Arity];
1097 var i = 0;
1098
1099 var gti = type as InflatedTypeSpec;
1100
1101 //
1102 // Inflating using outside type arguments, var v = new Foo<int> (), class Foo<T> {}
1103 //
1104 if (gti != null) {
1105 for (; i < targs.Length; ++i)
1106 targs[i] = Inflate (gti.TypeArguments[i]);
1107
1108 return gti.GetDefinition ().MakeGenericType (targs);
1109 }
1110
1111 //
1112 // Inflating parent using inside type arguments, class Foo<T> { ITest<T> foo; }
1113 //
1114 var args = type.MemberDefinition.TypeParameters;
1115 foreach (var ds_tp in args)
1116 targs[i++] = Inflate (ds_tp);
1117
1118 return type.MakeGenericType (targs);
1119 }
1120
1121 public TypeSpec TypeInstance {
1122 get { return type; }
1123 }
1124 }
1125
1126 //
1127 // Before emitting any code we have to change all MVAR references to VAR
1128 // when the method is of generic type and has hoisted variables
1129 //
1130 public class TypeParameterMutator
1131 {
1132 TypeParameter[] mvar;
1133 TypeParameter[] var;
1134 Dictionary<TypeSpec, TypeSpec> mutated_typespec = new Dictionary<TypeSpec, TypeSpec> ();
1135
1136 public TypeParameterMutator (TypeParameter[] mvar, TypeParameter[] var)
1137 {
1138 if (mvar.Length != var.Length)
1139 throw new ArgumentException ();
1140
1141 this.mvar = mvar;
1142 this.var = var;
1143 }
1144
1145 public TypeSpec Mutate (TypeSpec ts)
1146 {
1147 TypeSpec value;
1148 if (mutated_typespec.TryGetValue (ts, out value))
1149 return value;
1150
1151 value = ts.Mutate (this);
1152 mutated_typespec.Add (ts, value);
1153 return value;
1154 }
1155
1156 public FieldInfo Mutate (FieldSpec fs)
1157 {
1158 // TODO:
1159 return fs.GetMetaInfo ();
1160 }
1161
1162 public TypeParameterSpec Mutate (TypeParameterSpec tp)
1163 {
1164 for (int i = 0; i < mvar.Length; ++i) {
1165 if (mvar[i].Type == tp)
1166 return var[i].Type;
1167 }
1168
1169 return tp;
1170 }
1171
1172 public TypeSpec[] Mutate (TypeSpec[] targs)
1173 {
1174 TypeSpec[] mutated = new TypeSpec[targs.Length];
1175 bool changed = false;
1176 for (int i = 0; i < targs.Length; ++i) {
1177 mutated[i] = Mutate (targs[i]);
1178 changed |= targs[i] != mutated[i];
1179 }
1180
1181 return changed ? mutated : targs;
1182 }
1183 }
1184
1185 /// <summary>
1186 /// A TypeExpr which already resolved to a type parameter.
1187 /// </summary>
1188 public class TypeParameterExpr : TypeExpr {
1189
1190 public TypeParameterExpr (TypeParameter type_parameter, Location loc)
1191 {
1192 this.type = type_parameter.Type;
1193 this.eclass = ExprClass.TypeParameter;
1194 this.loc = loc;
1195 }
1196
1197 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
1198 {
1199 throw new NotSupportedException ();
1200 }
1201
1202 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
1203 {
1204 return this;
1205 }
1206
1207 public override bool CheckAccessLevel (IMemberContext ds)
1208 {
1209 return true;
1210 }
1211 }
1212
1213 public class InflatedTypeSpec : TypeSpec
1214 {
1215 TypeSpec[] targs;
1216 TypeParameterSpec[] constraints;
1217 readonly TypeSpec open_type;
1218
1219 public InflatedTypeSpec (TypeSpec openType, TypeSpec declaringType, TypeSpec[] targs)
1220 : base (openType.Kind, declaringType, openType.MemberDefinition, null, openType.Modifiers)
1221 {
1222 if (targs == null)
1223 throw new ArgumentNullException ("targs");
1224
1225 // this.state = openType.state;
1226 this.open_type = openType;
1227 this.targs = targs;
1228 }
1229
1230 #region Properties
1231
1232 public override TypeSpec BaseType {
1233 get {
1234 if (cache == null || (state & StateFlags.PendingBaseTypeInflate) != 0)
1235 InitializeMemberCache (true);
1236
1237 return base.BaseType;
1238 }
1239 }
1240
1241 //
1242 // Inflated type parameters with constraints array, mapping with type arguments is based on index
1243 //
1244 public TypeParameterSpec[] Constraints {
1245 get {
1246 if (constraints == null) {
1247 var inflator = new TypeParameterInflator (this, MemberDefinition.TypeParameters, targs);
1248 constraints = TypeParameterSpec.InflateConstraints (inflator, MemberDefinition.TypeParameters);
1249 }
1250
1251 return constraints;
1252 }
1253 }
1254
1255 public override IList<TypeSpec> Interfaces {
1256 get {
1257 if (cache == null)
1258 InitializeMemberCache (true);
1259
1260 return base.Interfaces;
1261 }
1262 }
1263
1264 public override MemberCache MemberCacheTypes {
1265 get {
1266 if (cache == null)
1267 InitializeMemberCache (true);
1268
1269 return cache;
1270 }
1271 }
1272
1273 //
1274 // Types used to inflate the generic type
1275 //
1276 public override TypeSpec[] TypeArguments {
1277 get {
1278 return targs;
1279 }
1280 }
1281
1282 #endregion
1283
1284 Type CreateMetaInfo (TypeParameterMutator mutator)
1285 {
1286 //
1287 // Converts nested type arguments into right order
1288 // Foo<string, bool>.Bar<int> => string, bool, int
1289 //
1290 var all = new List<Type> ();
1291 TypeSpec type = this;
1292 TypeSpec definition = type;
1293 do {
1294 if (type.GetDefinition().IsGeneric) {
1295 all.InsertRange (0,
1296 type.TypeArguments != TypeSpec.EmptyTypes ?
1297 type.TypeArguments.Select (l => l.GetMetaInfo ()) :
1298 type.MemberDefinition.TypeParameters.Select (l => l.GetMetaInfo ()));
1299 }
1300
1301 definition = definition.GetDefinition ();
1302 type = type.DeclaringType;
1303 } while (type != null);
1304
1305 return definition.GetMetaInfo ().MakeGenericType (all.ToArray ());
1306 }
1307
1308 public override ObsoleteAttribute GetAttributeObsolete ()
1309 {
1310 return open_type.GetAttributeObsolete ();
1311 }
1312
1313 protected override bool IsNotCLSCompliant ()
1314 {
1315 if (base.IsNotCLSCompliant ())
1316 return true;
1317
1318 foreach (var ta in TypeArguments) {
1319 if (ta.MemberDefinition.IsNotCLSCompliant ())
1320 return true;
1321 }
1322
1323 return false;
1324 }
1325
1326 public override TypeSpec GetDefinition ()
1327 {
1328 return open_type;
1329 }
1330
1331 public override Type GetMetaInfo ()
1332 {
1333 if (info == null)
1334 info = CreateMetaInfo (null);
1335
1336 return info;
1337 }
1338
1339 public override string GetSignatureForError ()
1340 {
1341 if (TypeManager.IsNullableType (open_type))
1342 return targs[0].GetSignatureForError () + "?";
1343
1344 if (MemberDefinition is AnonymousTypeClass)
1345 return ((AnonymousTypeClass) MemberDefinition).GetSignatureForError ();
1346
1347 return base.GetSignatureForError ();
1348 }
1349
1350 protected override string GetTypeNameSignature ()
1351 {
1352 if (targs.Length == 0 || MemberDefinition is AnonymousTypeClass)
1353 return null;
1354
1355 return "<" + TypeManager.CSharpName (targs) + ">";
1356 }
1357
1358 protected override void InitializeMemberCache (bool onlyTypes)
1359 {
1360 if (cache == null)
1361 cache = new MemberCache (open_type.MemberCache);
1362
1363 TypeParameterSpec[] tparams_full;
1364 TypeSpec[] targs_full = targs;
1365 if (IsNested) {
1366 //
1367 // Special case is needed when we are inflating an open type (nested type definition)
1368 // on inflated parent. Consider following case
1369 //
1370 // Foo<T>.Bar<U> => Foo<string>.Bar<U>
1371 //
1372 // Any later inflation of Foo<string>.Bar<U> has to also inflate T if used inside Bar<U>
1373 //
1374 List<TypeSpec> merged_targs = null;
1375 List<TypeParameterSpec> merged_tparams = null;
1376
1377 var type = DeclaringType;
1378
1379 do {
1380 if (type.TypeArguments.Length > 0) {
1381 if (merged_targs == null) {
1382 merged_targs = new List<TypeSpec> ();
1383 merged_tparams = new List<TypeParameterSpec> ();
1384 if (targs.Length > 0) {
1385 merged_targs.AddRange (targs);
1386 merged_tparams.AddRange (open_type.MemberDefinition.TypeParameters);
1387 }
1388 }
1389 merged_tparams.AddRange (type.MemberDefinition.TypeParameters);
1390 merged_targs.AddRange (type.TypeArguments);
1391 }
1392 type = type.DeclaringType;
1393 } while (type != null);
1394
1395 if (merged_targs != null) {
1396 // Type arguments are not in the right order but it should not matter in this case
1397 targs_full = merged_targs.ToArray ();
1398 tparams_full = merged_tparams.ToArray ();
1399 } else if (targs.Length == 0) {
1400 tparams_full = TypeParameterSpec.EmptyTypes;
1401 } else {
1402 tparams_full = open_type.MemberDefinition.TypeParameters;
1403 }
1404 } else if (targs.Length == 0) {
1405 tparams_full = TypeParameterSpec.EmptyTypes;
1406 } else {
1407 tparams_full = open_type.MemberDefinition.TypeParameters;
1408 }
1409
1410 var inflator = new TypeParameterInflator (this, tparams_full, targs_full);
1411
1412 //
1413 // Two stage inflate due to possible nested types recursive
1414 // references
1415 //
1416 // class A<T> {
1417 // B b;
1418 // class B {
1419 // T Value;
1420 // }
1421 // }
1422 //
1423 // When resolving type of `b' members of `B' cannot be
1424 // inflated because are not yet available in membercache
1425 //
1426 if ((state & StateFlags.PendingMemberCacheMembers) == 0) {
1427 open_type.MemberCache.InflateTypes (cache, inflator);
1428
1429 //
1430 // Inflate any implemented interfaces
1431 //
1432 if (open_type.Interfaces != null) {
1433 ifaces = new List<TypeSpec> (open_type.Interfaces.Count);
1434 foreach (var iface in open_type.Interfaces) {
1435 var iface_inflated = inflator.Inflate (iface);
1436 AddInterface (iface_inflated);
1437 }
1438 }
1439
1440 //
1441 // Handles the tricky case of recursive nested base generic type
1442 //
1443 // class A<T> : Base<A<T>.Nested> {
1444 // class Nested {}
1445 // }
1446 //
1447 // When inflating A<T>. base type is not yet known, secondary
1448 // inflation is required (not common case) once base scope
1449 // is known
1450 //
1451 if (open_type.BaseType == null) {
1452 if (IsClass)
1453 state |= StateFlags.PendingBaseTypeInflate;
1454 } else {
1455 BaseType = inflator.Inflate (open_type.BaseType);
1456 }
1457 } else if ((state & StateFlags.PendingBaseTypeInflate) != 0) {
1458 BaseType = inflator.Inflate (open_type.BaseType);
1459 state &= ~StateFlags.PendingBaseTypeInflate;
1460 }
1461
1462 if (onlyTypes) {
1463 state |= StateFlags.PendingMemberCacheMembers;
1464 return;
1465 }
1466
1467 var tc = open_type.MemberDefinition as TypeContainer;
1468 if (tc != null && !tc.HasMembersDefined)
1469 throw new InternalErrorException ("Inflating MemberCache with undefined members");
1470
1471 if ((state & StateFlags.PendingBaseTypeInflate) != 0) {
1472 BaseType = inflator.Inflate (open_type.BaseType);
1473 state &= ~StateFlags.PendingBaseTypeInflate;
1474 }
1475
1476 state &= ~StateFlags.PendingMemberCacheMembers;
1477 open_type.MemberCache.InflateMembers (cache, open_type, inflator);
1478 }
1479
1480 public override TypeSpec Mutate (TypeParameterMutator mutator)
1481 {
1482 var targs = TypeArguments;
1483 if (targs != null)
1484 targs = mutator.Mutate (targs);
1485
1486 var decl = DeclaringType;
1487 if (IsNested && DeclaringType.IsGenericOrParentIsGeneric)
1488 decl = mutator.Mutate (decl);
1489
1490 if (targs == TypeArguments && decl == DeclaringType)
1491 return this;
1492
1493 var mutated = (InflatedTypeSpec) MemberwiseClone ();
1494 if (decl != DeclaringType) {
1495 // Gets back MethodInfo in case of metaInfo was inflated
1496 //mutated.info = MemberCache.GetMember<TypeSpec> (DeclaringType.GetDefinition (), this).info;
1497
1498 mutated.declaringType = decl;
1499 mutated.state |= StateFlags.PendingMetaInflate;
1500 }
1501
1502 if (targs != null) {
1503 mutated.targs = targs;
1504 mutated.info = null;
1505 }
1506
1507 return mutated;
1508 }
1509 }
1510
1511
1512 //
1513 // Tracks the type arguments when instantiating a generic type. It's used
1514 // by both type arguments and type parameters
1515 //
1516 public class TypeArguments
1517 {
1518 List<FullNamedExpression> args;
1519 TypeSpec[] atypes;
1520
1521 public TypeArguments (params FullNamedExpression[] types)
1522 {
1523 this.args = new List<FullNamedExpression> (types);
1524 }
1525
1526 public void Add (FullNamedExpression type)
1527 {
1528 args.Add (type);
1529 }
1530
1531 // TODO: Kill this monster
1532 public TypeParameterName[] GetDeclarations ()
1533 {
1534 return args.ConvertAll (i => (TypeParameterName) i).ToArray ();
1535 }
1536
1537 /// <summary>
1538 /// We may only be used after Resolve() is called and return the fully
1539 /// resolved types.
1540 /// </summary>
1541 // TODO: Not needed, just return type from resolve
1542 public TypeSpec[] Arguments {
1543 get {
1544 return atypes;
1545 }
1546 }
1547
1548 public int Count {
1549 get {
1550 return args.Count;
1551 }
1552 }
1553
1554 public virtual bool IsEmpty {
1555 get {
1556 return false;
1557 }
1558 }
1559
1560 public string GetSignatureForError()
1561 {
1562 StringBuilder sb = new StringBuilder ();
1563 for (int i = 0; i < Count; ++i) {
1564 var expr = args[i];
1565 if (expr != null)
1566 sb.Append (expr.GetSignatureForError ());
1567
1568 if (i + 1 < Count)
1569 sb.Append (',');
1570 }
1571
1572 return sb.ToString ();
1573 }
1574
1575 /// <summary>
1576 /// Resolve the type arguments.
1577 /// </summary>
1578 public virtual bool Resolve (IMemberContext ec)
1579 {
1580 if (atypes != null)
1581 return atypes.Length != 0;
1582
1583 int count = args.Count;
1584 bool ok = true;
1585
1586 atypes = new TypeSpec [count];
1587
1588 for (int i = 0; i < count; i++){
1589 TypeExpr te = args[i].ResolveAsTypeTerminal (ec, false);
1590 if (te == null) {
1591 ok = false;
1592 continue;
1593 }
1594
1595 atypes[i] = te.Type;
1596
1597 if (te.Type.IsStatic) {
1598 ec.Compiler.Report.Error (718, te.Location, "`{0}': static classes cannot be used as generic arguments",
1599 te.GetSignatureForError ());
1600 ok = false;
1601 }
1602
1603 if (te.Type.IsPointer || TypeManager.IsSpecialType (te.Type)) {
1604 ec.Compiler.Report.Error (306, te.Location,
1605 "The type `{0}' may not be used as a type argument",
1606 te.GetSignatureForError ());
1607 ok = false;
1608 }
1609 }
1610
1611 if (!ok)
1612 atypes = TypeSpec.EmptyTypes;
1613
1614 return ok;
1615 }
1616
1617 public TypeArguments Clone ()
1618 {
1619 TypeArguments copy = new TypeArguments ();
1620 foreach (var ta in args)
1621 copy.args.Add (ta);
1622
1623 return copy;
1624 }
1625 }
1626
1627 public class UnboundTypeArguments : TypeArguments
1628 {
1629 public UnboundTypeArguments (int arity)
1630 : base (new FullNamedExpression[arity])
1631 {
1632 }
1633
1634 public override bool IsEmpty {
1635 get {
1636 return true;
1637 }
1638 }
1639
1640 public override bool Resolve (IMemberContext ec)
1641 {
1642 // should not be called
1643 throw new NotSupportedException ();
1644 }
1645 }
1646
1647 public class TypeParameterName : SimpleName
1648 {
1649 Attributes attributes;
1650 Variance variance;
1651
1652 public TypeParameterName (string name, Attributes attrs, Location loc)
1653 : this (name, attrs, Variance.None, loc)
1654 {
1655 }
1656
1657 public TypeParameterName (string name, Attributes attrs, Variance variance, Location loc)
1658 : base (name, loc)
1659 {
1660 attributes = attrs;
1661 this.variance = variance;
1662 }
1663
1664 public Attributes OptAttributes {
1665 get {
1666 return attributes;
1667 }
1668 }
1669
1670 public Variance Variance {
1671 get {
1672 return variance;
1673 }
1674 }
1675 }
1676
1677 //
1678 // A type expression of generic type with type arguments
1679 //
1680 class GenericTypeExpr : TypeExpr
1681 {
1682 TypeArguments args;
1683 TypeSpec open_type;
1684 bool constraints_checked;
1685
1686 /// <summary>
1687 /// Instantiate the generic type `t' with the type arguments `args'.
1688 /// Use this constructor if you already know the fully resolved
1689 /// generic type.
1690 /// </summary>
1691 public GenericTypeExpr (TypeSpec open_type, TypeArguments args, Location l)
1692 {
1693 this.open_type = open_type;
1694 loc = l;
1695 this.args = args;
1696 }
1697
1698 public TypeArguments TypeArguments {
1699 get { return args; }
1700 }
1701
1702 public override string GetSignatureForError ()
1703 {
1704 return TypeManager.CSharpName (type);
1705 }
1706
1707 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
1708 {
1709 if (!args.Resolve (ec))
1710 return null;
1711
1712 TypeSpec[] atypes = args.Arguments;
1713
1714 //
1715 // Now bind the parameters
1716 //
1717 type = open_type.MakeGenericType (atypes);
1718
1719 //
1720 // Check constraints when context is not method/base type
1721 //
1722 if (!ec.HasUnresolvedConstraints)
1723 CheckConstraints (ec);
1724
1725 return this;
1726 }
1727
1728 //
1729 // Checks the constraints of open generic type against type
1730 // arguments. Has to be called onafter all members are defined
1731 //
1732 public bool CheckConstraints (IMemberContext ec)
1733 {
1734 if (constraints_checked)
1735 return true;
1736
1737 constraints_checked = true;
1738
1739 var gtype = (InflatedTypeSpec) type;
1740 var constraints = gtype.Constraints;
1741 if (constraints == null)
1742 return true;
1743
1744 return ConstraintChecker.CheckAll (open_type, args.Arguments, constraints, loc, ec.Compiler.Report);
1745 }
1746
1747 public override bool CheckAccessLevel (IMemberContext mc)
1748 {
1749 DeclSpace c = mc.CurrentMemberDefinition as DeclSpace;
1750 if (c == null)
1751 c = mc.CurrentMemberDefinition.Parent;
1752
1753 return c.CheckAccessLevel (open_type);
1754 }
1755
1756 public bool HasDynamicArguments ()
1757 {
1758 return HasDynamicArguments (args.Arguments);
1759 }
1760
1761 static bool HasDynamicArguments (TypeSpec[] args)
1762 {
1763 foreach (var item in args) {
1764 if (item == InternalType.Dynamic)
1765 return true;
1766
1767 if (TypeManager.IsGenericType (item))
1768 return HasDynamicArguments (TypeManager.GetTypeArguments (item));
1769 }
1770
1771 return false;
1772 }
1773
1774 public override bool Equals (object obj)
1775 {
1776 GenericTypeExpr cobj = obj as GenericTypeExpr;
1777 if (cobj == null)
1778 return false;
1779
1780 if ((type == null) || (cobj.type == null))
1781 return false;
1782
1783 return type == cobj.type;
1784 }
1785
1786 public override int GetHashCode ()
1787 {
1788 return base.GetHashCode ();
1789 }
1790 }
1791
1792 static class ConstraintChecker
1793 {
1794 /// <summary>
1795 /// Check the constraints; we're called from ResolveAsTypeTerminal()
1796 /// after fully resolving the constructed type.
1797 /// </summary>
1798 public static bool CheckAll (MemberSpec context, TypeSpec[] targs, TypeParameterSpec[] tparams, Location loc, Report report)
1799 {
1800 for (int i = 0; i < tparams.Length; i++) {
1801 if (!CheckConstraint (context, targs [i], tparams [i], loc, report))
1802 return false;
1803 }
1804
1805 return true;
1806 }
1807
1808 static bool CheckConstraint (MemberSpec context, TypeSpec atype, TypeParameterSpec tparam, Location loc, Report report)
1809 {
1810 //
1811 // First, check the `class' and `struct' constraints.
1812 //
1813 if (tparam.HasSpecialClass && !TypeManager.IsReferenceType (atype)) {
1814 report.Error (452, loc,
1815 "The type `{0}' must be a reference type in order to use it as type parameter `{1}' in the generic type or method `{2}'",
1816 TypeManager.CSharpName (atype), tparam.GetSignatureForError (), context.GetSignatureForError ());
1817 return false;
1818 }
1819
1820 if (tparam.HasSpecialStruct && (!TypeManager.IsValueType (atype) || TypeManager.IsNullableType (atype))) {
1821 report.Error (453, loc,
1822 "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}'",
1823 TypeManager.CSharpName (atype), tparam.GetSignatureForError (), context.GetSignatureForError ());
1824 return false;
1825 }
1826
1827 //
1828 // The class constraint comes next.
1829 //
1830 if (tparam.HasTypeConstraint) {
1831 CheckConversion (context, atype, tparam, tparam.BaseType, loc, report);
1832 }
1833
1834 //
1835 // Now, check the interfaces and type parameters constraints
1836 //
1837 if (tparam.Interfaces != null) {
1838 if (TypeManager.IsNullableType (atype)) {
1839 report.Error (313, loc,
1840 "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",
1841 atype.GetSignatureForError (), tparam.GetSignatureForError (), context.GetSignatureForError ());
1842 } else {
1843 foreach (TypeSpec iface in tparam.Interfaces) {
1844 CheckConversion (context, atype, tparam, iface, loc, report);
1845 }
1846 }
1847 }
1848
1849 //
1850 // Finally, check the constructor constraint.
1851 //
1852 if (!tparam.HasSpecialConstructor)
1853 return true;
1854
1855 if (!HasDefaultConstructor (atype)) {
1856 report.SymbolRelatedToPreviousError (atype);
1857 report.Error (310, loc,
1858 "The type `{0}' must have a public parameterless constructor in order to use it as parameter `{1}' in the generic type or method `{2}'",
1859 TypeManager.CSharpName (atype), tparam.GetSignatureForError (), context.GetSignatureForError ());
1860 return false;
1861 }
1862
1863 return true;
1864 }
1865
1866 static void CheckConversion (MemberSpec context, TypeSpec atype, TypeParameterSpec tparam, TypeSpec ttype, Location loc, Report report)
1867 {
1868 var expr = new EmptyExpression (atype);
1869 if (!Convert.ImplicitStandardConversionExists (expr, ttype)) {
1870 report.SymbolRelatedToPreviousError (tparam);
1871 if (TypeManager.IsValueType (atype)) {
1872 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}'",
1873 atype.GetSignatureForError (), tparam.GetSignatureForError (), context.GetSignatureForError (), ttype.GetSignatureForError ());
1874 } else if (atype.IsGenericParameter) {
1875 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}'",
1876 atype.GetSignatureForError (), tparam.GetSignatureForError (), context.GetSignatureForError (), ttype.GetSignatureForError ());
1877 } else {
1878 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}'",
1879 atype.GetSignatureForError (), tparam.GetSignatureForError (), context.GetSignatureForError (), ttype.GetSignatureForError ());
1880 }
1881 }
1882 }
1883
1884 static bool HasDefaultConstructor (TypeSpec atype)
1885 {
1886 var tp = atype as TypeParameterSpec;
1887 if (tp != null) {
1888 return tp.HasSpecialConstructor || tp.HasSpecialStruct;
1889 }
1890
1891 if (atype.IsStruct || atype.IsEnum)
1892 return true;
1893
1894 if (atype.IsAbstract)
1895 return false;
1896
1897 var tdef = atype.GetDefinition ();
1898
1899 //
1900 // In some circumstances MemberCache is not yet populated and members
1901 // cannot be defined yet (recursive type new constraints)
1902 //
1903 // class A<T> where T : B<T>, new () {}
1904 // class B<T> where T : A<T>, new () {}
1905 //
1906 var tc = tdef.MemberDefinition as Class;
1907 if (tc != null) {
1908 if (tc.InstanceConstructors == null) {
1909 // Default ctor will be generated later
1910 return true;
1911 }
1912
1913 foreach (var c in tc.InstanceConstructors) {
1914 if (c.ParameterInfo.IsEmpty) {
1915 if ((c.ModFlags & Modifiers.PUBLIC) != 0)
1916 return true;
1917 }
1918 }
1919
1920 return false;
1921 }
1922
1923 var found = MemberCache.FindMember (tdef,
1924 MemberFilter.Constructor (ParametersCompiled.EmptyReadOnlyParameters),
1925 BindingRestriction.DeclaredOnly | BindingRestriction.InstanceOnly);
1926
1927 return found != null && (found.Modifiers & Modifiers.PUBLIC) != 0;
1928 }
1929 }
1930
1931 /// <summary>
1932 /// A generic method definition.
1933 /// </summary>
1934 public class GenericMethod : DeclSpace
1935 {
1936 ParametersCompiled parameters;
1937
1938 public GenericMethod (NamespaceEntry ns, DeclSpace parent, MemberName name,
1939 FullNamedExpression return_type, ParametersCompiled parameters)
1940 : base (ns, parent, name, null)
1941 {
1942 this.parameters = parameters;
1943 }
1944
1945 public GenericMethod (NamespaceEntry ns, DeclSpace parent, MemberName name, TypeParameter[] tparams,
1946 FullNamedExpression return_type, ParametersCompiled parameters)
1947 : this (ns, parent, name, return_type, parameters)
1948 {
1949 this.type_params = tparams;
1950 }
1951
1952 public override TypeParameter[] CurrentTypeParameters {
1953 get {
1954 return base.type_params;
1955 }
1956 }
1957
1958 public override TypeBuilder DefineType ()
1959 {
1960 throw new Exception ();
1961 }
1962
1963 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
1964 {
1965 throw new NotSupportedException ();
1966 }
1967
1968 public override bool Define ()
1969 {
1970 throw new NotSupportedException ();
1971 }
1972
1973 /// <summary>
1974 /// Define and resolve the type parameters.
1975 /// We're called from Method.Define().
1976 /// </summary>
1977 public bool Define (MethodOrOperator m)
1978 {
1979 TypeParameterName[] names = MemberName.TypeArguments.GetDeclarations ();
1980 string[] snames = new string [names.Length];
1981 for (int i = 0; i < names.Length; i++) {
1982 string type_argument_name = names[i].Name;
1983 int idx = parameters.GetParameterIndexByName (type_argument_name);
1984 if (idx >= 0) {
1985 Block b = m.Block;
1986 if (b == null)
1987 b = new Block (null);
1988
1989 b.Error_AlreadyDeclaredTypeParameter (Report, parameters [i].Location,
1990 type_argument_name, "method parameter");
1991 }
1992
1993 snames[i] = type_argument_name;
1994 }
1995
1996 GenericTypeParameterBuilder[] gen_params = m.MethodBuilder.DefineGenericParameters (snames);
1997 for (int i = 0; i < TypeParameters.Length; i++)
1998 TypeParameters [i].Define (gen_params [i], null);
1999
2000 return true;
2001 }
2002
2003 public void EmitAttributes ()
2004 {
2005 if (OptAttributes != null)
2006 OptAttributes.Emit ();
2007 }
2008
2009 public override string GetSignatureForError ()
2010 {
2011 return base.GetSignatureForError () + parameters.GetSignatureForError ();
2012 }
2013
2014 public override AttributeTargets AttributeTargets {
2015 get {
2016 return AttributeTargets.Method | AttributeTargets.ReturnValue;
2017 }
2018 }
2019
2020 public override string DocCommentHeader {
2021 get { return "M:"; }
2022 }
2023
2024 public new void VerifyClsCompliance ()
2025 {
2026 foreach (TypeParameter tp in TypeParameters) {
2027 tp.VerifyClsCompliance ();
2028 }
2029 }
2030 }
2031
2032 public partial class TypeManager
2033 {
2034 public static Variance CheckTypeVariance (TypeSpec t, Variance expected, IMemberContext member)
2035 {
2036 var tp = t as TypeParameterSpec;
2037 if (tp != null) {
2038 Variance v = tp.Variance;
2039 if (expected == Variance.None && v != expected ||
2040 expected == Variance.Covariant && v == Variance.Contravariant ||
2041 expected == Variance.Contravariant && v == Variance.Covariant) {
2042 ((TypeParameter)tp.MemberDefinition).ErrorInvalidVariance (member, expected);
2043 }
2044
2045 return expected;
2046 }
2047
2048 if (t.TypeArguments.Length > 0) {
2049 var targs_definition = t.MemberDefinition.TypeParameters;
2050 TypeSpec[] targs = GetTypeArguments (t);
2051 for (int i = 0; i < targs.Length; ++i) {
2052 Variance v = targs_definition[i].Variance;
2053 CheckTypeVariance (targs[i], (Variance) ((int)v * (int)expected), member);
2054 }
2055
2056 return expected;
2057 }
2058
2059 if (t.IsArray)
2060 return CheckTypeVariance (GetElementType (t), expected, member);
2061
2062 return Variance.None;
2063 }
2064
2065 /// <summary>
2066 /// Type inference. Try to infer the type arguments from `method',
2067 /// which is invoked with the arguments `arguments'. This is used
2068 /// when resolving an Invocation or a DelegateInvocation and the user
2069 /// did not explicitly specify type arguments.
2070 /// </summary>
2071 public static int InferTypeArguments (ResolveContext ec, Arguments arguments, ref MethodSpec method)
2072 {
2073 ATypeInference ti = ATypeInference.CreateInstance (arguments);
2074 TypeSpec[] i_args = ti.InferMethodArguments (ec, method);
2075 if (i_args == null)
2076 return ti.InferenceScore;
2077
2078 if (i_args.Length == 0)
2079 return 0;
2080
2081 method = method.MakeGenericMethod (i_args);
2082 return 0;
2083 }
2084 }
2085
2086 abstract class ATypeInference
2087 {
2088 protected readonly Arguments arguments;
2089 protected readonly int arg_count;
2090
2091 protected ATypeInference (Arguments arguments)
2092 {
2093 this.arguments = arguments;
2094 if (arguments != null)
2095 arg_count = arguments.Count;
2096 }
2097
2098 public static ATypeInference CreateInstance (Arguments arguments)
2099 {
2100 return new TypeInference (arguments);
2101 }
2102
2103 public virtual int InferenceScore {
2104 get {
2105 return int.MaxValue;
2106 }
2107 }
2108
2109 public abstract TypeSpec[] InferMethodArguments (ResolveContext ec, MethodSpec method);
2110 }
2111
2112 //
2113 // Implements C# type inference
2114 //
2115 class TypeInference : ATypeInference
2116 {
2117 //
2118 // Tracks successful rate of type inference
2119 //
2120 int score = int.MaxValue;
2121
2122 public TypeInference (Arguments arguments)
2123 : base (arguments)
2124 {
2125 }
2126
2127 public override int InferenceScore {
2128 get {
2129 return score;
2130 }
2131 }
2132
2133 public override TypeSpec[] InferMethodArguments (ResolveContext ec, MethodSpec method)
2134 {
2135 var method_generic_args = method.GenericDefinition.TypeParameters;
2136 TypeInferenceContext context = new TypeInferenceContext (method_generic_args);
2137 if (!context.UnfixedVariableExists)
2138 return TypeSpec.EmptyTypes;
2139
2140 AParametersCollection pd = method.Parameters;
2141 if (!InferInPhases (ec, context, pd))
2142 return null;
2143
2144 return context.InferredTypeArguments;
2145 }
2146
2147 //
2148 // Implements method type arguments inference
2149 //
2150 bool InferInPhases (ResolveContext ec, TypeInferenceContext tic, AParametersCollection methodParameters)
2151 {
2152 int params_arguments_start;
2153 if (methodParameters.HasParams) {
2154 params_arguments_start = methodParameters.Count - 1;
2155 } else {
2156 params_arguments_start = arg_count;
2157 }
2158
2159 TypeSpec [] ptypes = methodParameters.Types;
2160
2161 //
2162 // The first inference phase
2163 //
2164 TypeSpec method_parameter = null;
2165 for (int i = 0; i < arg_count; i++) {
2166 Argument a = arguments [i];
2167 if (a == null)
2168 continue;
2169
2170 if (i < params_arguments_start) {
2171 method_parameter = methodParameters.Types [i];
2172 } else if (i == params_arguments_start) {
2173 if (arg_count == params_arguments_start + 1 && TypeManager.HasElementType (a.Type))
2174 method_parameter = methodParameters.Types [params_arguments_start];
2175 else
2176 method_parameter = TypeManager.GetElementType (methodParameters.Types [params_arguments_start]);
2177
2178 ptypes = (TypeSpec[]) ptypes.Clone ();
2179 ptypes [i] = method_parameter;
2180 }
2181
2182 //
2183 // When a lambda expression, an anonymous method
2184 // is used an explicit argument type inference takes a place
2185 //
2186 AnonymousMethodExpression am = a.Expr as AnonymousMethodExpression;
2187 if (am != null) {
2188 if (am.ExplicitTypeInference (ec, tic, method_parameter))
2189 --score;
2190 continue;
2191 }
2192
2193 if (a.IsByRef) {
2194 score -= tic.ExactInference (a.Type, method_parameter);
2195 continue;
2196 }
2197
2198 if (a.Expr.Type == InternalType.Null)
2199 continue;
2200
2201 if (TypeManager.IsValueType (method_parameter)) {
2202 score -= tic.LowerBoundInference (a.Type, method_parameter);
2203 continue;
2204 }
2205
2206 //
2207 // Otherwise an output type inference is made
2208 //
2209 score -= tic.OutputTypeInference (ec, a.Expr, method_parameter);
2210 }
2211
2212 //
2213 // Part of the second phase but because it happens only once
2214 // we don't need to call it in cycle
2215 //
2216 bool fixed_any = false;
2217 if (!tic.FixIndependentTypeArguments (ec, ptypes, ref fixed_any))
2218 return false;
2219
2220 return DoSecondPhase (ec, tic, ptypes, !fixed_any);
2221 }
2222
2223 bool DoSecondPhase (ResolveContext ec, TypeInferenceContext tic, TypeSpec[] methodParameters, bool fixDependent)
2224 {
2225 bool fixed_any = false;
2226 if (fixDependent && !tic.FixDependentTypes (ec, ref fixed_any))
2227 return false;
2228
2229 // If no further unfixed type variables exist, type inference succeeds
2230 if (!tic.UnfixedVariableExists)
2231 return true;
2232
2233 if (!fixed_any && fixDependent)
2234 return false;
2235
2236 // For all arguments where the corresponding argument output types
2237 // contain unfixed type variables but the input types do not,
2238 // an output type inference is made
2239 for (int i = 0; i < arg_count; i++) {
2240
2241 // Align params arguments
2242 TypeSpec t_i = methodParameters [i >= methodParameters.Length ? methodParameters.Length - 1: i];
2243
2244 if (!TypeManager.IsDelegateType (t_i)) {
2245 if (t_i.GetDefinition () != TypeManager.expression_type)
2246 continue;
2247
2248 t_i = TypeManager.GetTypeArguments (t_i) [0];
2249 }
2250
2251 var mi = Delegate.GetInvokeMethod (ec.Compiler, t_i);
2252 TypeSpec rtype = mi.ReturnType;
2253
2254 if (tic.IsReturnTypeNonDependent (ec, mi, rtype))
2255 score -= tic.OutputTypeInference (ec, arguments [i].Expr, t_i);
2256 }
2257
2258
2259 return DoSecondPhase (ec, tic, methodParameters, true);
2260 }
2261 }
2262
2263 public class TypeInferenceContext
2264 {
2265 enum BoundKind
2266 {
2267 Exact = 0,
2268 Lower = 1,
2269 Upper = 2
2270 }
2271
2272 class BoundInfo
2273 {
2274 public readonly TypeSpec Type;
2275 public readonly BoundKind Kind;
2276
2277 public BoundInfo (TypeSpec type, BoundKind kind)
2278 {
2279 this.Type = type;
2280 this.Kind = kind;
2281 }
2282
2283 public override int GetHashCode ()
2284 {
2285 return Type.GetHashCode ();
2286 }
2287
2288 public override bool Equals (object obj)
2289 {
2290 BoundInfo a = (BoundInfo) obj;
2291 return Type == a.Type && Kind == a.Kind;
2292 }
2293 }
2294
2295 readonly TypeSpec[] unfixed_types;
2296 readonly TypeSpec[] fixed_types;
2297 readonly List<BoundInfo>[] bounds;
2298 bool failed;
2299
2300 // TODO MemberCache: Could it be TypeParameterSpec[] ??
2301 public TypeInferenceContext (TypeSpec[] typeArguments)
2302 {
2303 if (typeArguments.Length == 0)
2304 throw new ArgumentException ("Empty generic arguments");
2305
2306 fixed_types = new TypeSpec [typeArguments.Length];
2307 for (int i = 0; i < typeArguments.Length; ++i) {
2308 if (typeArguments [i].IsGenericParameter) {
2309 if (bounds == null) {
2310 bounds = new List<BoundInfo> [typeArguments.Length];
2311 unfixed_types = new TypeSpec [typeArguments.Length];
2312 }
2313 unfixed_types [i] = typeArguments [i];
2314 } else {
2315 fixed_types [i] = typeArguments [i];
2316 }
2317 }
2318 }
2319
2320 //
2321 // Used together with AddCommonTypeBound fo implement
2322 // 7.4.2.13 Finding the best common type of a set of expressions
2323 //
2324 public TypeInferenceContext ()
2325 {
2326 fixed_types = new TypeSpec [1];
2327 unfixed_types = new TypeSpec [1];
2328 unfixed_types[0] = InternalType.Arglist; // it can be any internal type
2329 bounds = new List<BoundInfo> [1];
2330 }
2331
2332 public TypeSpec[] InferredTypeArguments {
2333 get {
2334 return fixed_types;
2335 }
2336 }
2337
2338 public void AddCommonTypeBound (TypeSpec type)
2339 {
2340 AddToBounds (new BoundInfo (type, BoundKind.Lower), 0);
2341 }
2342
2343 void AddToBounds (BoundInfo bound, int index)
2344 {
2345 //
2346 // Some types cannot be used as type arguments
2347 //
2348 if (bound.Type == TypeManager.void_type || bound.Type.IsPointer)
2349 return;
2350
2351 var a = bounds [index];
2352 if (a == null) {
2353 a = new List<BoundInfo> ();
2354 bounds [index] = a;
2355 } else {
2356 if (a.Contains (bound))
2357 return;
2358 }
2359
2360 //
2361 // SPEC: does not cover type inference using constraints
2362 //
2363 //if (TypeManager.IsGenericParameter (t)) {
2364 // GenericConstraints constraints = TypeManager.GetTypeParameterConstraints (t);
2365 // if (constraints != null) {
2366 // //if (constraints.EffectiveBaseClass != null)
2367 // // t = constraints.EffectiveBaseClass;
2368 // }
2369 //}
2370 a.Add (bound);
2371 }
2372
2373 bool AllTypesAreFixed (TypeSpec[] types)
2374 {
2375 foreach (TypeSpec t in types) {
2376 if (t.IsGenericParameter) {
2377 if (!IsFixed (t))
2378 return false;
2379 continue;
2380 }
2381
2382 if (TypeManager.IsGenericType (t))
2383 return AllTypesAreFixed (TypeManager.GetTypeArguments (t));
2384 }
2385
2386 return true;
2387 }
2388
2389 //
2390 // 26.3.3.8 Exact Inference
2391 //
2392 public int ExactInference (TypeSpec u, TypeSpec v)
2393 {
2394 // If V is an array type
2395 if (v.IsArray) {
2396 if (!u.IsArray)
2397 return 0;
2398
2399 // TODO MemberCache: GetMetaInfo ()
2400 if (u.GetMetaInfo ().GetArrayRank () != v.GetMetaInfo ().GetArrayRank ())
2401 return 0;
2402
2403 return ExactInference (TypeManager.GetElementType (u), TypeManager.GetElementType (v));
2404 }
2405
2406 // If V is constructed type and U is constructed type
2407 if (TypeManager.IsGenericType (v)) {
2408 if (!TypeManager.IsGenericType (u))
2409 return 0;
2410
2411 TypeSpec [] ga_u = TypeManager.GetTypeArguments (u);
2412 TypeSpec [] ga_v = TypeManager.GetTypeArguments (v);
2413 if (ga_u.Length != ga_v.Length)
2414 return 0;
2415
2416 int score = 0;
2417 for (int i = 0; i < ga_u.Length; ++i)
2418 score += ExactInference (ga_u [i], ga_v [i]);
2419
2420 return score > 0 ? 1 : 0;
2421 }
2422
2423 // If V is one of the unfixed type arguments
2424 int pos = IsUnfixed (v);
2425 if (pos == -1)
2426 return 0;
2427
2428 AddToBounds (new BoundInfo (u, BoundKind.Exact), pos);
2429 return 1;
2430 }
2431
2432 public bool FixAllTypes (ResolveContext ec)
2433 {
2434 for (int i = 0; i < unfixed_types.Length; ++i) {
2435 if (!FixType (ec, i))
2436 return false;
2437 }
2438 return true;
2439 }
2440
2441 //
2442 // All unfixed type variables Xi are fixed for which all of the following hold:
2443 // a, There is at least one type variable Xj that depends on Xi
2444 // b, Xi has a non-empty set of bounds
2445 //
2446 public bool FixDependentTypes (ResolveContext ec, ref bool fixed_any)
2447 {
2448 for (int i = 0; i < unfixed_types.Length; ++i) {
2449 if (unfixed_types[i] == null)
2450 continue;
2451
2452 if (bounds[i] == null)
2453 continue;
2454
2455 if (!FixType (ec, i))
2456 return false;
2457
2458 fixed_any = true;
2459 }
2460
2461 return true;
2462 }
2463
2464 //
2465 // All unfixed type variables Xi which depend on no Xj are fixed
2466 //
2467 public bool FixIndependentTypeArguments (ResolveContext ec, TypeSpec[] methodParameters, ref bool fixed_any)
2468 {
2469 var types_to_fix = new List<TypeSpec> (unfixed_types);
2470 for (int i = 0; i < methodParameters.Length; ++i) {
2471 TypeSpec t = methodParameters[i];
2472
2473 if (!TypeManager.IsDelegateType (t)) {
2474 if (TypeManager.expression_type == null || t.MemberDefinition != TypeManager.expression_type.MemberDefinition)
2475 continue;
2476
2477 t = TypeManager.GetTypeArguments (t) [0];
2478 }
2479
2480 if (t.IsGenericParameter)
2481 continue;
2482
2483 var invoke = Delegate.GetInvokeMethod (ec.Compiler, t);
2484 TypeSpec rtype = invoke.ReturnType;
2485 if (!rtype.IsGenericParameter && !TypeManager.IsGenericType (rtype))
2486 continue;
2487
2488 // Remove dependent types, they cannot be fixed yet
2489 RemoveDependentTypes (types_to_fix, rtype);
2490 }
2491
2492 foreach (TypeSpec t in types_to_fix) {
2493 if (t == null)
2494 continue;
2495
2496 int idx = IsUnfixed (t);
2497 if (idx >= 0 && !FixType (ec, idx)) {
2498 return false;
2499 }
2500 }
2501
2502 fixed_any = types_to_fix.Count > 0;
2503 return true;
2504 }
2505
2506 //
2507 // 26.3.3.10 Fixing
2508 //
2509 public bool FixType (ResolveContext ec, int i)
2510 {
2511 // It's already fixed
2512 if (unfixed_types[i] == null)
2513 throw new InternalErrorException ("Type argument has been already fixed");
2514
2515 if (failed)
2516 return false;
2517
2518 var candidates = bounds [i];
2519 if (candidates == null)
2520 return false;
2521
2522 if (candidates.Count == 1) {
2523 unfixed_types[i] = null;
2524 TypeSpec t = candidates[0].Type;
2525 if (t == InternalType.Null)
2526 return false;
2527
2528 fixed_types [i] = t;
2529 return true;
2530 }
2531
2532 //
2533 // Determines a unique type from which there is
2534 // a standard implicit conversion to all the other
2535 // candidate types.
2536 //
2537 TypeSpec best_candidate = null;
2538 int cii;
2539 int candidates_count = candidates.Count;
2540 for (int ci = 0; ci < candidates_count; ++ci) {
2541 BoundInfo bound = candidates [ci];
2542 for (cii = 0; cii < candidates_count; ++cii) {
2543 if (cii == ci)
2544 continue;
2545
2546 BoundInfo cbound = candidates[cii];
2547
2548 // Same type parameters with different bounds
2549 if (cbound.Type == bound.Type) {
2550 if (bound.Kind != BoundKind.Exact)
2551 bound = cbound;
2552
2553 continue;
2554 }
2555
2556 if (bound.Kind == BoundKind.Exact || cbound.Kind == BoundKind.Exact) {
2557 if (cbound.Kind != BoundKind.Exact) {
2558 if (!Convert.ImplicitConversionExists (ec, new TypeExpression (cbound.Type, Location.Null), bound.Type)) {
2559 break;
2560 }
2561
2562 continue;
2563 }
2564
2565 if (bound.Kind != BoundKind.Exact) {
2566 if (!Convert.ImplicitConversionExists (ec, new TypeExpression (bound.Type, Location.Null), cbound.Type)) {
2567 break;
2568 }
2569
2570 bound = cbound;
2571 continue;
2572 }
2573
2574 break;
2575 }
2576
2577 if (bound.Kind == BoundKind.Lower) {
2578 if (!Convert.ImplicitConversionExists (ec, new TypeExpression (cbound.Type, Location.Null), bound.Type)) {
2579 break;
2580 }
2581 } else {
2582 if (!Convert.ImplicitConversionExists (ec, new TypeExpression (bound.Type, Location.Null), cbound.Type)) {
2583 break;
2584 }
2585 }
2586 }
2587
2588 if (cii != candidates_count)
2589 continue;
2590
2591 if (best_candidate != null && best_candidate != bound.Type)
2592 return false;
2593
2594 best_candidate = bound.Type;
2595 }
2596
2597 if (best_candidate == null)
2598 return false;
2599
2600 unfixed_types[i] = null;
2601 fixed_types[i] = best_candidate;
2602 return true;
2603 }
2604
2605 //
2606 // Uses inferred or partially infered types to inflate delegate type argument. Returns
2607 // null when type parameter was not yet inferres
2608 //
2609 public TypeSpec InflateGenericArgument (TypeSpec parameter)
2610 {
2611 var tp = parameter as TypeParameterSpec;
2612 if (tp != null) {
2613 //
2614 // Type inference work on generic arguments (MVAR) only
2615 //
2616 if (!tp.IsMethodOwned)
2617 return parameter;
2618
2619 return fixed_types [tp.DeclaredPosition] ?? parameter;
2620 }
2621
2622 var gt = parameter as InflatedTypeSpec;
2623 if (gt != null) {
2624 var inflated_targs = new TypeSpec [gt.TypeArguments.Length];
2625 for (int ii = 0; ii < inflated_targs.Length; ++ii) {
2626 var inflated = InflateGenericArgument (gt.TypeArguments [ii]);
2627 if (inflated == null)
2628 return null;
2629
2630 inflated_targs[ii] = inflated;
2631 }
2632
2633 return gt.GetDefinition ().MakeGenericType (inflated_targs);
2634 }
2635
2636 return parameter;
2637 }
2638
2639 //
2640 // Tests whether all delegate input arguments are fixed and generic output type
2641 // requires output type inference
2642 //
2643 public bool IsReturnTypeNonDependent (ResolveContext ec, MethodSpec invoke, TypeSpec returnType)
2644 {
2645 if (returnType.IsGenericParameter) {
2646 if (IsFixed (returnType))
2647 return false;
2648 } else if (TypeManager.IsGenericType (returnType)) {
2649 if (TypeManager.IsDelegateType (returnType)) {
2650 invoke = Delegate.GetInvokeMethod (ec.Compiler, returnType);
2651 return IsReturnTypeNonDependent (ec, invoke, invoke.ReturnType);
2652 }
2653
2654 TypeSpec[] g_args = TypeManager.GetTypeArguments (returnType);
2655
2656 // At least one unfixed return type has to exist
2657 if (AllTypesAreFixed (g_args))
2658 return false;
2659 } else {
2660 return false;
2661 }
2662
2663 // All generic input arguments have to be fixed
2664 AParametersCollection d_parameters = invoke.Parameters;
2665 return AllTypesAreFixed (d_parameters.Types);
2666 }
2667
2668 bool IsFixed (TypeSpec type)
2669 {
2670 return IsUnfixed (type) == -1;
2671 }
2672
2673 int IsUnfixed (TypeSpec type)
2674 {
2675 if (!type.IsGenericParameter)
2676 return -1;
2677
2678 //return unfixed_types[type.GenericParameterPosition] != null;
2679 for (int i = 0; i < unfixed_types.Length; ++i) {
2680 if (unfixed_types [i] == type)
2681 return i;
2682 }
2683
2684 return -1;
2685 }
2686
2687 //
2688 // 26.3.3.9 Lower-bound Inference
2689 //
2690 public int LowerBoundInference (TypeSpec u, TypeSpec v)
2691 {
2692 return LowerBoundInference (u, v, false);
2693 }
2694
2695 //
2696 // Lower-bound (false) or Upper-bound (true) inference based on inversed argument
2697 //
2698 int LowerBoundInference (TypeSpec u, TypeSpec v, bool inversed)
2699 {
2700 // If V is one of the unfixed type arguments
2701 int pos = IsUnfixed (v);
2702 if (pos != -1) {
2703 AddToBounds (new BoundInfo (u, inversed ? BoundKind.Upper : BoundKind.Lower), pos);
2704 return 1;
2705 }
2706
2707 // If U is an array type
2708 var u_ac = u as ArrayContainer;
2709 if (u_ac != null) {
2710 var v_ac = v as ArrayContainer;
2711 if (v_ac != null) {
2712 if (u_ac.Rank != v_ac.Rank)
2713 return 0;
2714
2715 if (TypeManager.IsValueType (u_ac.Element))
2716 return ExactInference (u_ac.Element, v_ac.Element);
2717
2718 return LowerBoundInference (u_ac.Element, v_ac.Element, inversed);
2719 }
2720
2721 if (u_ac.Rank != 1)
2722 return 0;
2723
2724 if (TypeManager.IsGenericType (v)) {
2725 TypeSpec g_v = v.GetDefinition ();
2726 if (g_v != TypeManager.generic_ilist_type &&
2727 g_v != TypeManager.generic_icollection_type &&
2728 g_v != TypeManager.generic_ienumerable_type)
2729 return 0;
2730
2731 var v_i = TypeManager.GetTypeArguments (v) [0];
2732 if (TypeManager.IsValueType (u_ac.Element))
2733 return ExactInference (u_ac.Element, v_i);
2734
2735 return LowerBoundInference (u_ac.Element, v_i);
2736 }
2737 } else if (TypeManager.IsGenericType (v)) {
2738 //
2739 // if V is a constructed type C<V1..Vk> and there is a unique type C<U1..Uk>
2740 // such that U is identical to, inherits from (directly or indirectly),
2741 // or implements (directly or indirectly) C<U1..Uk>
2742 //
2743 var u_candidates = new List<TypeSpec> ();
2744 var open_v = v.MemberDefinition;
2745
2746 for (TypeSpec t = u; t != null; t = t.BaseType) {
2747 if (open_v == t.MemberDefinition)
2748 u_candidates.Add (t);
2749
2750 if (t.Interfaces != null) {
2751 foreach (var iface in t.Interfaces) {
2752 if (open_v == iface.MemberDefinition)
2753 u_candidates.Add (iface);
2754 }
2755 }
2756 }
2757
2758 TypeSpec [] unique_candidate_targs = null;
2759 TypeSpec[] ga_v = TypeManager.GetTypeArguments (v);
2760 foreach (TypeSpec u_candidate in u_candidates) {
2761 //
2762 // The unique set of types U1..Uk means that if we have an interface I<T>,
2763 // class U : I<int>, I<long> then no type inference is made when inferring
2764 // type I<T> by applying type U because T could be int or long
2765 //
2766 if (unique_candidate_targs != null) {
2767 TypeSpec[] second_unique_candidate_targs = TypeManager.GetTypeArguments (u_candidate);
2768 if (TypeSpecComparer.Default.Equals (unique_candidate_targs, second_unique_candidate_targs)) {
2769 unique_candidate_targs = second_unique_candidate_targs;
2770 continue;
2771 }
2772
2773 //
2774 // This should always cause type inference failure
2775 //
2776 failed = true;
2777 return 1;
2778 }
2779
2780 unique_candidate_targs = TypeManager.GetTypeArguments (u_candidate);
2781 }
2782
2783 if (unique_candidate_targs != null) {
2784 var ga_open_v = open_v.TypeParameters;
2785 int score = 0;
2786 for (int i = 0; i < unique_candidate_targs.Length; ++i) {
2787 Variance variance = ga_open_v [i].Variance;
2788
2789 TypeSpec u_i = unique_candidate_targs [i];
2790 if (variance == Variance.None || TypeManager.IsValueType (u_i)) {
2791 if (ExactInference (u_i, ga_v [i]) == 0)
2792 ++score;
2793 } else {
2794 bool upper_bound = (variance == Variance.Contravariant && !inversed) ||
2795 (variance == Variance.Covariant && inversed);
2796
2797 if (LowerBoundInference (u_i, ga_v [i], upper_bound) == 0)
2798 ++score;
2799 }
2800 }
2801 return score;
2802 }
2803 }
2804
2805 return 0;
2806 }
2807
2808 //
2809 // 26.3.3.6 Output Type Inference
2810 //
2811 public int OutputTypeInference (ResolveContext ec, Expression e, TypeSpec t)
2812 {
2813 // If e is a lambda or anonymous method with inferred return type
2814 AnonymousMethodExpression ame = e as AnonymousMethodExpression;
2815 if (ame != null) {
2816 TypeSpec rt = ame.InferReturnType (ec, this, t);
2817 var invoke = Delegate.GetInvokeMethod (ec.Compiler, t);
2818
2819 if (rt == null) {
2820 AParametersCollection pd = invoke.Parameters;
2821 return ame.Parameters.Count == pd.Count ? 1 : 0;
2822 }
2823
2824 TypeSpec rtype = invoke.ReturnType;
2825 return LowerBoundInference (rt, rtype) + 1;
2826 }
2827
2828 //
2829 // if E is a method group and T is a delegate type or expression tree type
2830 // return type Tb with parameter types T1..Tk and return type Tb, and overload
2831 // resolution of E with the types T1..Tk yields a single method with return type U,
2832 // then a lower-bound inference is made from U for Tb.
2833 //
2834 if (e is MethodGroupExpr) {
2835 if (!TypeManager.IsDelegateType (t)) {
2836 if (TypeManager.expression_type == null || t.MemberDefinition != TypeManager.expression_type.MemberDefinition)
2837 return 0;
2838
2839 t = TypeManager.GetTypeArguments (t)[0];
2840 }
2841
2842 var invoke = Delegate.GetInvokeMethod (ec.Compiler, t);
2843 TypeSpec rtype = invoke.ReturnType;
2844
2845 if (!rtype.IsGenericParameter && !TypeManager.IsGenericType (rtype))
2846 return 0;
2847
2848 // LAMESPEC: Standard does not specify that all methodgroup arguments
2849 // has to be fixed but it does not specify how to do recursive type inference
2850 // either. We choose the simple option and infer return type only
2851 // if all delegate generic arguments are fixed.
2852 TypeSpec[] param_types = new TypeSpec [invoke.Parameters.Count];
2853 for (int i = 0; i < param_types.Length; ++i) {
2854 var inflated = InflateGenericArgument (invoke.Parameters.Types[i]);
2855 if (inflated == null)
2856 return 0;
2857
2858 param_types[i] = inflated;
2859 }
2860
2861 MethodGroupExpr mg = (MethodGroupExpr) e;
2862 Arguments args = DelegateCreation.CreateDelegateMethodArguments (invoke.Parameters, param_types, e.Location);
2863 mg = mg.OverloadResolve (ec, ref args, true, e.Location);
2864 if (mg == null)
2865 return 0;
2866
2867 return LowerBoundInference (mg.BestCandidate.ReturnType, rtype) + 1;
2868 }
2869
2870 //
2871 // if e is an expression with type U, then
2872 // a lower-bound inference is made from U for T
2873 //
2874 return LowerBoundInference (e.Type, t) * 2;
2875 }
2876
2877 void RemoveDependentTypes (List<TypeSpec> types, TypeSpec returnType)
2878 {
2879 int idx = IsUnfixed (returnType);
2880 if (idx >= 0) {
2881 types [idx] = null;
2882 return;
2883 }
2884
2885 if (TypeManager.IsGenericType (returnType)) {
2886 foreach (TypeSpec t in TypeManager.GetTypeArguments (returnType)) {
2887 RemoveDependentTypes (types, t);
2888 }
2889 }
2890 }
2891
2892 public bool UnfixedVariableExists {
2893 get {
2894 if (unfixed_types == null)
2895 return false;
2896
2897 foreach (TypeSpec ut in unfixed_types)
2898 if (ut != null)
2899 return true;
2900 return false;
2901 }
2902 }
2903 }
2904 }
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