SemaCXXScopeSpec.cpp revision d10099e5c8238fa0327f03921cf2e3c8975c881e 
1//===--- SemaCXXScopeSpec.cpp - Semantic Analysis for C++ scope specifiers-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements C++ semantic analysis for scope specifiers.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Sema/SemaInternal.h"
15#include "clang/Sema/Lookup.h"
16#include "clang/Sema/Template.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclTemplate.h"
19#include "clang/AST/ExprCXX.h"
20#include "clang/AST/NestedNameSpecifier.h"
21#include "clang/Basic/PartialDiagnostic.h"
22#include "clang/Sema/DeclSpec.h"
23#include "TypeLocBuilder.h"
24#include "llvm/ADT/STLExtras.h"
25#include "llvm/Support/raw_ostream.h"
26using namespace clang;
27
28/// \brief Find the current instantiation that associated with the given type.
29static CXXRecordDecl *getCurrentInstantiationOf(QualType T,
30                                                DeclContext *CurContext) {
31  if (T.isNull())
32    return 0;
33
34  const Type *Ty = T->getCanonicalTypeInternal().getTypePtr();
35  if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
36    CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl());
37    if (!T->isDependentType())
38      return Record;
39
40    // This may be a member of a class template or class template partial
41    // specialization. If it's part of the current semantic context, then it's
42    // an injected-class-name;
43    for (; !CurContext->isFileContext(); CurContext = CurContext->getParent())
44      if (CurContext->Equals(Record))
45        return Record;
46
47    return 0;
48  } else if (isa<InjectedClassNameType>(Ty))
49    return cast<InjectedClassNameType>(Ty)->getDecl();
50  else
51    return 0;
52}
53
54/// \brief Compute the DeclContext that is associated with the given type.
55///
56/// \param T the type for which we are attempting to find a DeclContext.
57///
58/// \returns the declaration context represented by the type T,
59/// or NULL if the declaration context cannot be computed (e.g., because it is
60/// dependent and not the current instantiation).
61DeclContext *Sema::computeDeclContext(QualType T) {
62  if (!T->isDependentType())
63    if (const TagType *Tag = T->getAs<TagType>())
64      return Tag->getDecl();
65
66  return ::getCurrentInstantiationOf(T, CurContext);
67}
68
69/// \brief Compute the DeclContext that is associated with the given
70/// scope specifier.
71///
72/// \param SS the C++ scope specifier as it appears in the source
73///
74/// \param EnteringContext when true, we will be entering the context of
75/// this scope specifier, so we can retrieve the declaration context of a
76/// class template or class template partial specialization even if it is
77/// not the current instantiation.
78///
79/// \returns the declaration context represented by the scope specifier @p SS,
80/// or NULL if the declaration context cannot be computed (e.g., because it is
81/// dependent and not the current instantiation).
82DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
83                                      bool EnteringContext) {
84  if (!SS.isSet() || SS.isInvalid())
85    return 0;
86
87  NestedNameSpecifier *NNS
88    = static_cast<NestedNameSpecifier *>(SS.getScopeRep());
89  if (NNS->isDependent()) {
90    // If this nested-name-specifier refers to the current
91    // instantiation, return its DeclContext.
92    if (CXXRecordDecl *Record = getCurrentInstantiationOf(NNS))
93      return Record;
94
95    if (EnteringContext) {
96      const Type *NNSType = NNS->getAsType();
97      if (!NNSType) {
98        return 0;
99      }
100
101      // Look through type alias templates, per C++0x [temp.dep.type]p1.
102      NNSType = Context.getCanonicalType(NNSType);
103      if (const TemplateSpecializationType *SpecType
104            = NNSType->getAs<TemplateSpecializationType>()) {
105        // We are entering the context of the nested name specifier, so try to
106        // match the nested name specifier to either a primary class template
107        // or a class template partial specialization.
108        if (ClassTemplateDecl *ClassTemplate
109              = dyn_cast_or_null<ClassTemplateDecl>(
110                            SpecType->getTemplateName().getAsTemplateDecl())) {
111          QualType ContextType
112            = Context.getCanonicalType(QualType(SpecType, 0));
113
114          // If the type of the nested name specifier is the same as the
115          // injected class name of the named class template, we're entering
116          // into that class template definition.
117          QualType Injected
118            = ClassTemplate->getInjectedClassNameSpecialization();
119          if (Context.hasSameType(Injected, ContextType))
120            return ClassTemplate->getTemplatedDecl();
121
122          // If the type of the nested name specifier is the same as the
123          // type of one of the class template's class template partial
124          // specializations, we're entering into the definition of that
125          // class template partial specialization.
126          if (ClassTemplatePartialSpecializationDecl *PartialSpec
127                = ClassTemplate->findPartialSpecialization(ContextType))
128            return PartialSpec;
129        }
130      } else if (const RecordType *RecordT = NNSType->getAs<RecordType>()) {
131        // The nested name specifier refers to a member of a class template.
132        return RecordT->getDecl();
133      }
134    }
135
136    return 0;
137  }
138
139  switch (NNS->getKind()) {
140  case NestedNameSpecifier::Identifier:
141    llvm_unreachable("Dependent nested-name-specifier has no DeclContext");
142
143  case NestedNameSpecifier::Namespace:
144    return NNS->getAsNamespace();
145
146  case NestedNameSpecifier::NamespaceAlias:
147    return NNS->getAsNamespaceAlias()->getNamespace();
148
149  case NestedNameSpecifier::TypeSpec:
150  case NestedNameSpecifier::TypeSpecWithTemplate: {
151    const TagType *Tag = NNS->getAsType()->getAs<TagType>();
152    assert(Tag && "Non-tag type in nested-name-specifier");
153    return Tag->getDecl();
154  }
155
156  case NestedNameSpecifier::Global:
157    return Context.getTranslationUnitDecl();
158  }
159
160  llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
161}
162
163bool Sema::isDependentScopeSpecifier(const CXXScopeSpec &SS) {
164  if (!SS.isSet() || SS.isInvalid())
165    return false;
166
167  NestedNameSpecifier *NNS
168    = static_cast<NestedNameSpecifier *>(SS.getScopeRep());
169  return NNS->isDependent();
170}
171
172// \brief Determine whether this C++ scope specifier refers to an
173// unknown specialization, i.e., a dependent type that is not the
174// current instantiation.
175bool Sema::isUnknownSpecialization(const CXXScopeSpec &SS) {
176  if (!isDependentScopeSpecifier(SS))
177    return false;
178
179  NestedNameSpecifier *NNS
180    = static_cast<NestedNameSpecifier *>(SS.getScopeRep());
181  return getCurrentInstantiationOf(NNS) == 0;
182}
183
184/// \brief If the given nested name specifier refers to the current
185/// instantiation, return the declaration that corresponds to that
186/// current instantiation (C++0x [temp.dep.type]p1).
187///
188/// \param NNS a dependent nested name specifier.
189CXXRecordDecl *Sema::getCurrentInstantiationOf(NestedNameSpecifier *NNS) {
190  assert(getLangOpts().CPlusPlus && "Only callable in C++");
191  assert(NNS->isDependent() && "Only dependent nested-name-specifier allowed");
192
193  if (!NNS->getAsType())
194    return 0;
195
196  QualType T = QualType(NNS->getAsType(), 0);
197  return ::getCurrentInstantiationOf(T, CurContext);
198}
199
200/// \brief Require that the context specified by SS be complete.
201///
202/// If SS refers to a type, this routine checks whether the type is
203/// complete enough (or can be made complete enough) for name lookup
204/// into the DeclContext. A type that is not yet completed can be
205/// considered "complete enough" if it is a class/struct/union/enum
206/// that is currently being defined. Or, if we have a type that names
207/// a class template specialization that is not a complete type, we
208/// will attempt to instantiate that class template.
209bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
210                                      DeclContext *DC) {
211  assert(DC != 0 && "given null context");
212
213  TagDecl *tag = dyn_cast<TagDecl>(DC);
214
215  // If this is a dependent type, then we consider it complete.
216  if (!tag || tag->isDependentContext())
217    return false;
218
219  // If we're currently defining this type, then lookup into the
220  // type is okay: don't complain that it isn't complete yet.
221  QualType type = Context.getTypeDeclType(tag);
222  const TagType *tagType = type->getAs<TagType>();
223  if (tagType && tagType->isBeingDefined())
224    return false;
225
226  SourceLocation loc = SS.getLastQualifierNameLoc();
227  if (loc.isInvalid()) loc = SS.getRange().getBegin();
228
229  // The type must be complete.
230  if (RequireCompleteType(loc, type, diag::err_incomplete_nested_name_spec,
231                          SS.getRange())) {
232    SS.SetInvalid(SS.getRange());
233    return true;
234  }
235
236  // Fixed enum types are complete, but they aren't valid as scopes
237  // until we see a definition, so awkwardly pull out this special
238  // case.
239  const EnumType *enumType = dyn_cast_or_null<EnumType>(tagType);
240  if (!enumType || enumType->getDecl()->isCompleteDefinition())
241    return false;
242
243  // Try to instantiate the definition, if this is a specialization of an
244  // enumeration temploid.
245  EnumDecl *ED = enumType->getDecl();
246  if (EnumDecl *Pattern = ED->getInstantiatedFromMemberEnum()) {
247    MemberSpecializationInfo *MSI = ED->getMemberSpecializationInfo();
248    if (MSI->getTemplateSpecializationKind() != TSK_ExplicitSpecialization) {
249      if (InstantiateEnum(loc, ED, Pattern, getTemplateInstantiationArgs(ED),
250                          TSK_ImplicitInstantiation)) {
251        SS.SetInvalid(SS.getRange());
252        return true;
253      }
254      return false;
255    }
256  }
257
258  Diag(loc, diag::err_incomplete_nested_name_spec)
259    << type << SS.getRange();
260  SS.SetInvalid(SS.getRange());
261  return true;
262}
263
264bool Sema::ActOnCXXGlobalScopeSpecifier(Scope *S, SourceLocation CCLoc,
265                                        CXXScopeSpec &SS) {
266  SS.MakeGlobal(Context, CCLoc);
267  return false;
268}
269
270/// \brief Determines whether the given declaration is an valid acceptable
271/// result for name lookup of a nested-name-specifier.
272bool Sema::isAcceptableNestedNameSpecifier(NamedDecl *SD) {
273  if (!SD)
274    return false;
275
276  // Namespace and namespace aliases are fine.
277  if (isa<NamespaceDecl>(SD) || isa<NamespaceAliasDecl>(SD))
278    return true;
279
280  if (!isa<TypeDecl>(SD))
281    return false;
282
283  // Determine whether we have a class (or, in C++11, an enum) or
284  // a typedef thereof. If so, build the nested-name-specifier.
285  QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
286  if (T->isDependentType())
287    return true;
288  else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) {
289    if (TD->getUnderlyingType()->isRecordType() ||
290        (Context.getLangOpts().CPlusPlus0x &&
291         TD->getUnderlyingType()->isEnumeralType()))
292      return true;
293  } else if (isa<RecordDecl>(SD) ||
294             (Context.getLangOpts().CPlusPlus0x && isa<EnumDecl>(SD)))
295    return true;
296
297  return false;
298}
299
300/// \brief If the given nested-name-specifier begins with a bare identifier
301/// (e.g., Base::), perform name lookup for that identifier as a
302/// nested-name-specifier within the given scope, and return the result of that
303/// name lookup.
304NamedDecl *Sema::FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS) {
305  if (!S || !NNS)
306    return 0;
307
308  while (NNS->getPrefix())
309    NNS = NNS->getPrefix();
310
311  if (NNS->getKind() != NestedNameSpecifier::Identifier)
312    return 0;
313
314  LookupResult Found(*this, NNS->getAsIdentifier(), SourceLocation(),
315                     LookupNestedNameSpecifierName);
316  LookupName(Found, S);
317  assert(!Found.isAmbiguous() && "Cannot handle ambiguities here yet");
318
319  if (!Found.isSingleResult())
320    return 0;
321
322  NamedDecl *Result = Found.getFoundDecl();
323  if (isAcceptableNestedNameSpecifier(Result))
324    return Result;
325
326  return 0;
327}
328
329bool Sema::isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
330                                        SourceLocation IdLoc,
331                                        IdentifierInfo &II,
332                                        ParsedType ObjectTypePtr) {
333  QualType ObjectType = GetTypeFromParser(ObjectTypePtr);
334  LookupResult Found(*this, &II, IdLoc, LookupNestedNameSpecifierName);
335
336  // Determine where to perform name lookup
337  DeclContext *LookupCtx = 0;
338  bool isDependent = false;
339  if (!ObjectType.isNull()) {
340    // This nested-name-specifier occurs in a member access expression, e.g.,
341    // x->B::f, and we are looking into the type of the object.
342    assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
343    LookupCtx = computeDeclContext(ObjectType);
344    isDependent = ObjectType->isDependentType();
345  } else if (SS.isSet()) {
346    // This nested-name-specifier occurs after another nested-name-specifier,
347    // so long into the context associated with the prior nested-name-specifier.
348    LookupCtx = computeDeclContext(SS, false);
349    isDependent = isDependentScopeSpecifier(SS);
350    Found.setContextRange(SS.getRange());
351  }
352
353  if (LookupCtx) {
354    // Perform "qualified" name lookup into the declaration context we
355    // computed, which is either the type of the base of a member access
356    // expression or the declaration context associated with a prior
357    // nested-name-specifier.
358
359    // The declaration context must be complete.
360    if (!LookupCtx->isDependentContext() &&
361        RequireCompleteDeclContext(SS, LookupCtx))
362      return false;
363
364    LookupQualifiedName(Found, LookupCtx);
365  } else if (isDependent) {
366    return false;
367  } else {
368    LookupName(Found, S);
369  }
370  Found.suppressDiagnostics();
371
372  if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
373    return isa<NamespaceDecl>(ND) || isa<NamespaceAliasDecl>(ND);
374
375  return false;
376}
377
378namespace {
379
380// Callback to only accept typo corrections that can be a valid C++ member
381// intializer: either a non-static field member or a base class.
382class NestedNameSpecifierValidatorCCC : public CorrectionCandidateCallback {
383 public:
384  explicit NestedNameSpecifierValidatorCCC(Sema &SRef)
385      : SRef(SRef) {}
386
387  virtual bool ValidateCandidate(const TypoCorrection &candidate) {
388    return SRef.isAcceptableNestedNameSpecifier(candidate.getCorrectionDecl());
389  }
390
391 private:
392  Sema &SRef;
393};
394
395}
396
397/// \brief Build a new nested-name-specifier for "identifier::", as described
398/// by ActOnCXXNestedNameSpecifier.
399///
400/// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
401/// that it contains an extra parameter \p ScopeLookupResult, which provides
402/// the result of name lookup within the scope of the nested-name-specifier
403/// that was computed at template definition time.
404///
405/// If ErrorRecoveryLookup is true, then this call is used to improve error
406/// recovery.  This means that it should not emit diagnostics, it should
407/// just return true on failure.  It also means it should only return a valid
408/// scope if it *knows* that the result is correct.  It should not return in a
409/// dependent context, for example. Nor will it extend \p SS with the scope
410/// specifier.
411bool Sema::BuildCXXNestedNameSpecifier(Scope *S,
412                                       IdentifierInfo &Identifier,
413                                       SourceLocation IdentifierLoc,
414                                       SourceLocation CCLoc,
415                                       QualType ObjectType,
416                                       bool EnteringContext,
417                                       CXXScopeSpec &SS,
418                                       NamedDecl *ScopeLookupResult,
419                                       bool ErrorRecoveryLookup) {
420  LookupResult Found(*this, &Identifier, IdentifierLoc,
421                     LookupNestedNameSpecifierName);
422
423  // Determine where to perform name lookup
424  DeclContext *LookupCtx = 0;
425  bool isDependent = false;
426  if (!ObjectType.isNull()) {
427    // This nested-name-specifier occurs in a member access expression, e.g.,
428    // x->B::f, and we are looking into the type of the object.
429    assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
430    LookupCtx = computeDeclContext(ObjectType);
431    isDependent = ObjectType->isDependentType();
432  } else if (SS.isSet()) {
433    // This nested-name-specifier occurs after another nested-name-specifier,
434    // so look into the context associated with the prior nested-name-specifier.
435    LookupCtx = computeDeclContext(SS, EnteringContext);
436    isDependent = isDependentScopeSpecifier(SS);
437    Found.setContextRange(SS.getRange());
438  }
439
440
441  bool ObjectTypeSearchedInScope = false;
442  if (LookupCtx) {
443    // Perform "qualified" name lookup into the declaration context we
444    // computed, which is either the type of the base of a member access
445    // expression or the declaration context associated with a prior
446    // nested-name-specifier.
447
448    // The declaration context must be complete.
449    if (!LookupCtx->isDependentContext() &&
450        RequireCompleteDeclContext(SS, LookupCtx))
451      return true;
452
453    LookupQualifiedName(Found, LookupCtx);
454
455    if (!ObjectType.isNull() && Found.empty()) {
456      // C++ [basic.lookup.classref]p4:
457      //   If the id-expression in a class member access is a qualified-id of
458      //   the form
459      //
460      //        class-name-or-namespace-name::...
461      //
462      //   the class-name-or-namespace-name following the . or -> operator is
463      //   looked up both in the context of the entire postfix-expression and in
464      //   the scope of the class of the object expression. If the name is found
465      //   only in the scope of the class of the object expression, the name
466      //   shall refer to a class-name. If the name is found only in the
467      //   context of the entire postfix-expression, the name shall refer to a
468      //   class-name or namespace-name. [...]
469      //
470      // Qualified name lookup into a class will not find a namespace-name,
471      // so we do not need to diagnose that case specifically. However,
472      // this qualified name lookup may find nothing. In that case, perform
473      // unqualified name lookup in the given scope (if available) or
474      // reconstruct the result from when name lookup was performed at template
475      // definition time.
476      if (S)
477        LookupName(Found, S);
478      else if (ScopeLookupResult)
479        Found.addDecl(ScopeLookupResult);
480
481      ObjectTypeSearchedInScope = true;
482    }
483  } else if (!isDependent) {
484    // Perform unqualified name lookup in the current scope.
485    LookupName(Found, S);
486  }
487
488  // If we performed lookup into a dependent context and did not find anything,
489  // that's fine: just build a dependent nested-name-specifier.
490  if (Found.empty() && isDependent &&
491      !(LookupCtx && LookupCtx->isRecord() &&
492        (!cast<CXXRecordDecl>(LookupCtx)->hasDefinition() ||
493         !cast<CXXRecordDecl>(LookupCtx)->hasAnyDependentBases()))) {
494    // Don't speculate if we're just trying to improve error recovery.
495    if (ErrorRecoveryLookup)
496      return true;
497
498    // We were not able to compute the declaration context for a dependent
499    // base object type or prior nested-name-specifier, so this
500    // nested-name-specifier refers to an unknown specialization. Just build
501    // a dependent nested-name-specifier.
502    SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc);
503    return false;
504  }
505
506  // FIXME: Deal with ambiguities cleanly.
507
508  if (Found.empty() && !ErrorRecoveryLookup) {
509    // We haven't found anything, and we're not recovering from a
510    // different kind of error, so look for typos.
511    DeclarationName Name = Found.getLookupName();
512    NestedNameSpecifierValidatorCCC Validator(*this);
513    TypoCorrection Corrected;
514    Found.clear();
515    if ((Corrected = CorrectTypo(Found.getLookupNameInfo(),
516                                 Found.getLookupKind(), S, &SS, Validator,
517                                 LookupCtx, EnteringContext))) {
518      std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
519      std::string CorrectedQuotedStr(Corrected.getQuoted(getLangOpts()));
520      if (LookupCtx)
521        Diag(Found.getNameLoc(), diag::err_no_member_suggest)
522          << Name << LookupCtx << CorrectedQuotedStr << SS.getRange()
523          << FixItHint::CreateReplacement(Found.getNameLoc(), CorrectedStr);
524      else
525        Diag(Found.getNameLoc(), diag::err_undeclared_var_use_suggest)
526          << Name << CorrectedQuotedStr
527          << FixItHint::CreateReplacement(Found.getNameLoc(), CorrectedStr);
528
529      if (NamedDecl *ND = Corrected.getCorrectionDecl()) {
530        Diag(ND->getLocation(), diag::note_previous_decl) << CorrectedQuotedStr;
531        Found.addDecl(ND);
532      }
533      Found.setLookupName(Corrected.getCorrection());
534    } else {
535      Found.setLookupName(&Identifier);
536    }
537  }
538
539  NamedDecl *SD = Found.getAsSingle<NamedDecl>();
540  if (isAcceptableNestedNameSpecifier(SD)) {
541    if (!ObjectType.isNull() && !ObjectTypeSearchedInScope &&
542        !getLangOpts().CPlusPlus0x) {
543      // C++03 [basic.lookup.classref]p4:
544      //   [...] If the name is found in both contexts, the
545      //   class-name-or-namespace-name shall refer to the same entity.
546      //
547      // We already found the name in the scope of the object. Now, look
548      // into the current scope (the scope of the postfix-expression) to
549      // see if we can find the same name there. As above, if there is no
550      // scope, reconstruct the result from the template instantiation itself.
551      //
552      // Note that C++11 does *not* perform this redundant lookup.
553      NamedDecl *OuterDecl;
554      if (S) {
555        LookupResult FoundOuter(*this, &Identifier, IdentifierLoc,
556                                LookupNestedNameSpecifierName);
557        LookupName(FoundOuter, S);
558        OuterDecl = FoundOuter.getAsSingle<NamedDecl>();
559      } else
560        OuterDecl = ScopeLookupResult;
561
562      if (isAcceptableNestedNameSpecifier(OuterDecl) &&
563          OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() &&
564          (!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) ||
565           !Context.hasSameType(
566                            Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)),
567                               Context.getTypeDeclType(cast<TypeDecl>(SD))))) {
568         if (ErrorRecoveryLookup)
569           return true;
570
571         Diag(IdentifierLoc,
572              diag::err_nested_name_member_ref_lookup_ambiguous)
573           << &Identifier;
574         Diag(SD->getLocation(), diag::note_ambig_member_ref_object_type)
575           << ObjectType;
576         Diag(OuterDecl->getLocation(), diag::note_ambig_member_ref_scope);
577
578         // Fall through so that we'll pick the name we found in the object
579         // type, since that's probably what the user wanted anyway.
580       }
581    }
582
583    // If we're just performing this lookup for error-recovery purposes,
584    // don't extend the nested-name-specifier. Just return now.
585    if (ErrorRecoveryLookup)
586      return false;
587
588    if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD)) {
589      SS.Extend(Context, Namespace, IdentifierLoc, CCLoc);
590      return false;
591    }
592
593    if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD)) {
594      SS.Extend(Context, Alias, IdentifierLoc, CCLoc);
595      return false;
596    }
597
598    QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
599    TypeLocBuilder TLB;
600    if (isa<InjectedClassNameType>(T)) {
601      InjectedClassNameTypeLoc InjectedTL
602        = TLB.push<InjectedClassNameTypeLoc>(T);
603      InjectedTL.setNameLoc(IdentifierLoc);
604    } else if (isa<RecordType>(T)) {
605      RecordTypeLoc RecordTL = TLB.push<RecordTypeLoc>(T);
606      RecordTL.setNameLoc(IdentifierLoc);
607    } else if (isa<TypedefType>(T)) {
608      TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(T);
609      TypedefTL.setNameLoc(IdentifierLoc);
610    } else if (isa<EnumType>(T)) {
611      EnumTypeLoc EnumTL = TLB.push<EnumTypeLoc>(T);
612      EnumTL.setNameLoc(IdentifierLoc);
613    } else if (isa<TemplateTypeParmType>(T)) {
614      TemplateTypeParmTypeLoc TemplateTypeTL
615        = TLB.push<TemplateTypeParmTypeLoc>(T);
616      TemplateTypeTL.setNameLoc(IdentifierLoc);
617    } else if (isa<UnresolvedUsingType>(T)) {
618      UnresolvedUsingTypeLoc UnresolvedTL
619        = TLB.push<UnresolvedUsingTypeLoc>(T);
620      UnresolvedTL.setNameLoc(IdentifierLoc);
621    } else if (isa<SubstTemplateTypeParmType>(T)) {
622      SubstTemplateTypeParmTypeLoc TL
623        = TLB.push<SubstTemplateTypeParmTypeLoc>(T);
624      TL.setNameLoc(IdentifierLoc);
625    } else if (isa<SubstTemplateTypeParmPackType>(T)) {
626      SubstTemplateTypeParmPackTypeLoc TL
627        = TLB.push<SubstTemplateTypeParmPackTypeLoc>(T);
628      TL.setNameLoc(IdentifierLoc);
629    } else {
630      llvm_unreachable("Unhandled TypeDecl node in nested-name-specifier");
631    }
632
633    if (T->isEnumeralType())
634      Diag(IdentifierLoc, diag::warn_cxx98_compat_enum_nested_name_spec);
635
636    SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
637              CCLoc);
638    return false;
639  }
640
641  // Otherwise, we have an error case.  If we don't want diagnostics, just
642  // return an error now.
643  if (ErrorRecoveryLookup)
644    return true;
645
646  // If we didn't find anything during our lookup, try again with
647  // ordinary name lookup, which can help us produce better error
648  // messages.
649  if (Found.empty()) {
650    Found.clear(LookupOrdinaryName);
651    LookupName(Found, S);
652  }
653
654  // In Microsoft mode, if we are within a templated function and we can't
655  // resolve Identifier, then extend the SS with Identifier. This will have
656  // the effect of resolving Identifier during template instantiation.
657  // The goal is to be able to resolve a function call whose
658  // nested-name-specifier is located inside a dependent base class.
659  // Example:
660  //
661  // class C {
662  // public:
663  //    static void foo2() {  }
664  // };
665  // template <class T> class A { public: typedef C D; };
666  //
667  // template <class T> class B : public A<T> {
668  // public:
669  //   void foo() { D::foo2(); }
670  // };
671  if (getLangOpts().MicrosoftExt) {
672    DeclContext *DC = LookupCtx ? LookupCtx : CurContext;
673    if (DC->isDependentContext() && DC->isFunctionOrMethod()) {
674      SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc);
675      return false;
676    }
677  }
678
679  unsigned DiagID;
680  if (!Found.empty())
681    DiagID = diag::err_expected_class_or_namespace;
682  else if (SS.isSet()) {
683    Diag(IdentifierLoc, diag::err_no_member)
684      << &Identifier << LookupCtx << SS.getRange();
685    return true;
686  } else
687    DiagID = diag::err_undeclared_var_use;
688
689  if (SS.isSet())
690    Diag(IdentifierLoc, DiagID) << &Identifier << SS.getRange();
691  else
692    Diag(IdentifierLoc, DiagID) << &Identifier;
693
694  return true;
695}
696
697bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
698                                       IdentifierInfo &Identifier,
699                                       SourceLocation IdentifierLoc,
700                                       SourceLocation CCLoc,
701                                       ParsedType ObjectType,
702                                       bool EnteringContext,
703                                       CXXScopeSpec &SS) {
704  if (SS.isInvalid())
705    return true;
706
707  return BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, CCLoc,
708                                     GetTypeFromParser(ObjectType),
709                                     EnteringContext, SS,
710                                     /*ScopeLookupResult=*/0, false);
711}
712
713bool Sema::ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
714                                               const DeclSpec &DS,
715                                               SourceLocation ColonColonLoc) {
716  if (SS.isInvalid() || DS.getTypeSpecType() == DeclSpec::TST_error)
717    return true;
718
719  assert(DS.getTypeSpecType() == DeclSpec::TST_decltype);
720
721  QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
722  if (!T->isDependentType() && !T->getAs<TagType>()) {
723    Diag(DS.getTypeSpecTypeLoc(), diag::err_expected_class)
724      << T << getLangOpts().CPlusPlus;
725    return true;
726  }
727
728  TypeLocBuilder TLB;
729  DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T);
730  DecltypeTL.setNameLoc(DS.getTypeSpecTypeLoc());
731  SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
732            ColonColonLoc);
733  return false;
734}
735
736/// IsInvalidUnlessNestedName - This method is used for error recovery
737/// purposes to determine whether the specified identifier is only valid as
738/// a nested name specifier, for example a namespace name.  It is
739/// conservatively correct to always return false from this method.
740///
741/// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
742bool Sema::IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
743                                     IdentifierInfo &Identifier,
744                                     SourceLocation IdentifierLoc,
745                                     SourceLocation ColonLoc,
746                                     ParsedType ObjectType,
747                                     bool EnteringContext) {
748  if (SS.isInvalid())
749    return false;
750
751  return !BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, ColonLoc,
752                                      GetTypeFromParser(ObjectType),
753                                      EnteringContext, SS,
754                                      /*ScopeLookupResult=*/0, true);
755}
756
757bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
758                                       CXXScopeSpec &SS,
759                                       SourceLocation TemplateKWLoc,
760                                       TemplateTy Template,
761                                       SourceLocation TemplateNameLoc,
762                                       SourceLocation LAngleLoc,
763                                       ASTTemplateArgsPtr TemplateArgsIn,
764                                       SourceLocation RAngleLoc,
765                                       SourceLocation CCLoc,
766                                       bool EnteringContext) {
767  if (SS.isInvalid())
768    return true;
769
770  // Translate the parser's template argument list in our AST format.
771  TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
772  translateTemplateArguments(TemplateArgsIn, TemplateArgs);
773
774  if (DependentTemplateName *DTN = Template.get().getAsDependentTemplateName()){
775    // Handle a dependent template specialization for which we cannot resolve
776    // the template name.
777    assert(DTN->getQualifier()
778             == static_cast<NestedNameSpecifier*>(SS.getScopeRep()));
779    QualType T = Context.getDependentTemplateSpecializationType(ETK_None,
780                                                          DTN->getQualifier(),
781                                                          DTN->getIdentifier(),
782                                                                TemplateArgs);
783
784    // Create source-location information for this type.
785    TypeLocBuilder Builder;
786    DependentTemplateSpecializationTypeLoc SpecTL
787      = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
788    SpecTL.setElaboratedKeywordLoc(SourceLocation());
789    SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
790    SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
791    SpecTL.setTemplateNameLoc(TemplateNameLoc);
792    SpecTL.setLAngleLoc(LAngleLoc);
793    SpecTL.setRAngleLoc(RAngleLoc);
794    for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
795      SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
796
797    SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
798              CCLoc);
799    return false;
800  }
801
802
803  if (Template.get().getAsOverloadedTemplate() ||
804      isa<FunctionTemplateDecl>(Template.get().getAsTemplateDecl())) {
805    SourceRange R(TemplateNameLoc, RAngleLoc);
806    if (SS.getRange().isValid())
807      R.setBegin(SS.getRange().getBegin());
808
809    Diag(CCLoc, diag::err_non_type_template_in_nested_name_specifier)
810      << Template.get() << R;
811    NoteAllFoundTemplates(Template.get());
812    return true;
813  }
814
815  // We were able to resolve the template name to an actual template.
816  // Build an appropriate nested-name-specifier.
817  QualType T = CheckTemplateIdType(Template.get(), TemplateNameLoc,
818                                   TemplateArgs);
819  if (T.isNull())
820    return true;
821
822  // Alias template specializations can produce types which are not valid
823  // nested name specifiers.
824  if (!T->isDependentType() && !T->getAs<TagType>()) {
825    Diag(TemplateNameLoc, diag::err_nested_name_spec_non_tag) << T;
826    NoteAllFoundTemplates(Template.get());
827    return true;
828  }
829
830  // Provide source-location information for the template specialization type.
831  TypeLocBuilder Builder;
832  TemplateSpecializationTypeLoc SpecTL
833    = Builder.push<TemplateSpecializationTypeLoc>(T);
834  SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
835  SpecTL.setTemplateNameLoc(TemplateNameLoc);
836  SpecTL.setLAngleLoc(LAngleLoc);
837  SpecTL.setRAngleLoc(RAngleLoc);
838  for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
839    SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
840
841
842  SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
843            CCLoc);
844  return false;
845}
846
847namespace {
848  /// \brief A structure that stores a nested-name-specifier annotation,
849  /// including both the nested-name-specifier
850  struct NestedNameSpecifierAnnotation {
851    NestedNameSpecifier *NNS;
852  };
853}
854
855void *Sema::SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS) {
856  if (SS.isEmpty() || SS.isInvalid())
857    return 0;
858
859  void *Mem = Context.Allocate((sizeof(NestedNameSpecifierAnnotation) +
860                                                        SS.location_size()),
861                               llvm::alignOf<NestedNameSpecifierAnnotation>());
862  NestedNameSpecifierAnnotation *Annotation
863    = new (Mem) NestedNameSpecifierAnnotation;
864  Annotation->NNS = SS.getScopeRep();
865  memcpy(Annotation + 1, SS.location_data(), SS.location_size());
866  return Annotation;
867}
868
869void Sema::RestoreNestedNameSpecifierAnnotation(void *AnnotationPtr,
870                                                SourceRange AnnotationRange,
871                                                CXXScopeSpec &SS) {
872  if (!AnnotationPtr) {
873    SS.SetInvalid(AnnotationRange);
874    return;
875  }
876
877  NestedNameSpecifierAnnotation *Annotation
878    = static_cast<NestedNameSpecifierAnnotation *>(AnnotationPtr);
879  SS.Adopt(NestedNameSpecifierLoc(Annotation->NNS, Annotation + 1));
880}
881
882bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
883  assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
884
885  NestedNameSpecifier *Qualifier =
886    static_cast<NestedNameSpecifier*>(SS.getScopeRep());
887
888  // There are only two places a well-formed program may qualify a
889  // declarator: first, when defining a namespace or class member
890  // out-of-line, and second, when naming an explicitly-qualified
891  // friend function.  The latter case is governed by
892  // C++03 [basic.lookup.unqual]p10:
893  //   In a friend declaration naming a member function, a name used
894  //   in the function declarator and not part of a template-argument
895  //   in a template-id is first looked up in the scope of the member
896  //   function's class. If it is not found, or if the name is part of
897  //   a template-argument in a template-id, the look up is as
898  //   described for unqualified names in the definition of the class
899  //   granting friendship.
900  // i.e. we don't push a scope unless it's a class member.
901
902  switch (Qualifier->getKind()) {
903  case NestedNameSpecifier::Global:
904  case NestedNameSpecifier::Namespace:
905  case NestedNameSpecifier::NamespaceAlias:
906    // These are always namespace scopes.  We never want to enter a
907    // namespace scope from anything but a file context.
908    return CurContext->getRedeclContext()->isFileContext();
909
910  case NestedNameSpecifier::Identifier:
911  case NestedNameSpecifier::TypeSpec:
912  case NestedNameSpecifier::TypeSpecWithTemplate:
913    // These are never namespace scopes.
914    return true;
915  }
916
917  llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
918}
919
920/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
921/// scope or nested-name-specifier) is parsed, part of a declarator-id.
922/// After this method is called, according to [C++ 3.4.3p3], names should be
923/// looked up in the declarator-id's scope, until the declarator is parsed and
924/// ActOnCXXExitDeclaratorScope is called.
925/// The 'SS' should be a non-empty valid CXXScopeSpec.
926bool Sema::ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS) {
927  assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
928
929  if (SS.isInvalid()) return true;
930
931  DeclContext *DC = computeDeclContext(SS, true);
932  if (!DC) return true;
933
934  // Before we enter a declarator's context, we need to make sure that
935  // it is a complete declaration context.
936  if (!DC->isDependentContext() && RequireCompleteDeclContext(SS, DC))
937    return true;
938
939  EnterDeclaratorContext(S, DC);
940
941  // Rebuild the nested name specifier for the new scope.
942  if (DC->isDependentContext())
943    RebuildNestedNameSpecifierInCurrentInstantiation(SS);
944
945  return false;
946}
947
948/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
949/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
950/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
951/// Used to indicate that names should revert to being looked up in the
952/// defining scope.
953void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
954  assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
955  if (SS.isInvalid())
956    return;
957  assert(!SS.isInvalid() && computeDeclContext(SS, true) &&
958         "exiting declarator scope we never really entered");
959  ExitDeclaratorContext(S);
960}
961