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 "TypeLocBuilder.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/DeclTemplate.h"
18 #include "clang/AST/ExprCXX.h"
19 #include "clang/AST/NestedNameSpecifier.h"
20 #include "clang/Basic/PartialDiagnostic.h"
21 #include "clang/Sema/DeclSpec.h"
22 #include "clang/Sema/Lookup.h"
23 #include "clang/Sema/Template.h"
24 #include "llvm/ADT/STLExtras.h"
25 #include "llvm/Support/raw_ostream.h"
26 using namespace clang;
27
28 /// \brief Find the current instantiation that associated with the given type.
getCurrentInstantiationOf(QualType T,DeclContext * CurContext)29 static CXXRecordDecl *getCurrentInstantiationOf(QualType T,
30 DeclContext *CurContext) {
31 if (T.isNull())
32 return nullptr;
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 (!Record->isDependentContext() ||
38 Record->isCurrentInstantiation(CurContext))
39 return Record;
40
41 return nullptr;
42 } else if (isa<InjectedClassNameType>(Ty))
43 return cast<InjectedClassNameType>(Ty)->getDecl();
44 else
45 return nullptr;
46 }
47
48 /// \brief Compute the DeclContext that is associated with the given type.
49 ///
50 /// \param T the type for which we are attempting to find a DeclContext.
51 ///
52 /// \returns the declaration context represented by the type T,
53 /// or NULL if the declaration context cannot be computed (e.g., because it is
54 /// dependent and not the current instantiation).
computeDeclContext(QualType T)55 DeclContext *Sema::computeDeclContext(QualType T) {
56 if (!T->isDependentType())
57 if (const TagType *Tag = T->getAs<TagType>())
58 return Tag->getDecl();
59
60 return ::getCurrentInstantiationOf(T, CurContext);
61 }
62
63 /// \brief Compute the DeclContext that is associated with the given
64 /// scope specifier.
65 ///
66 /// \param SS the C++ scope specifier as it appears in the source
67 ///
68 /// \param EnteringContext when true, we will be entering the context of
69 /// this scope specifier, so we can retrieve the declaration context of a
70 /// class template or class template partial specialization even if it is
71 /// not the current instantiation.
72 ///
73 /// \returns the declaration context represented by the scope specifier @p SS,
74 /// or NULL if the declaration context cannot be computed (e.g., because it is
75 /// dependent and not the current instantiation).
computeDeclContext(const CXXScopeSpec & SS,bool EnteringContext)76 DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
77 bool EnteringContext) {
78 if (!SS.isSet() || SS.isInvalid())
79 return nullptr;
80
81 NestedNameSpecifier *NNS = SS.getScopeRep();
82 if (NNS->isDependent()) {
83 // If this nested-name-specifier refers to the current
84 // instantiation, return its DeclContext.
85 if (CXXRecordDecl *Record = getCurrentInstantiationOf(NNS))
86 return Record;
87
88 if (EnteringContext) {
89 const Type *NNSType = NNS->getAsType();
90 if (!NNSType) {
91 return nullptr;
92 }
93
94 // Look through type alias templates, per C++0x [temp.dep.type]p1.
95 NNSType = Context.getCanonicalType(NNSType);
96 if (const TemplateSpecializationType *SpecType
97 = NNSType->getAs<TemplateSpecializationType>()) {
98 // We are entering the context of the nested name specifier, so try to
99 // match the nested name specifier to either a primary class template
100 // or a class template partial specialization.
101 if (ClassTemplateDecl *ClassTemplate
102 = dyn_cast_or_null<ClassTemplateDecl>(
103 SpecType->getTemplateName().getAsTemplateDecl())) {
104 QualType ContextType
105 = Context.getCanonicalType(QualType(SpecType, 0));
106
107 // If the type of the nested name specifier is the same as the
108 // injected class name of the named class template, we're entering
109 // into that class template definition.
110 QualType Injected
111 = ClassTemplate->getInjectedClassNameSpecialization();
112 if (Context.hasSameType(Injected, ContextType))
113 return ClassTemplate->getTemplatedDecl();
114
115 // If the type of the nested name specifier is the same as the
116 // type of one of the class template's class template partial
117 // specializations, we're entering into the definition of that
118 // class template partial specialization.
119 if (ClassTemplatePartialSpecializationDecl *PartialSpec
120 = ClassTemplate->findPartialSpecialization(ContextType))
121 return PartialSpec;
122 }
123 } else if (const RecordType *RecordT = NNSType->getAs<RecordType>()) {
124 // The nested name specifier refers to a member of a class template.
125 return RecordT->getDecl();
126 }
127 }
128
129 return nullptr;
130 }
131
132 switch (NNS->getKind()) {
133 case NestedNameSpecifier::Identifier:
134 llvm_unreachable("Dependent nested-name-specifier has no DeclContext");
135
136 case NestedNameSpecifier::Namespace:
137 return NNS->getAsNamespace();
138
139 case NestedNameSpecifier::NamespaceAlias:
140 return NNS->getAsNamespaceAlias()->getNamespace();
141
142 case NestedNameSpecifier::TypeSpec:
143 case NestedNameSpecifier::TypeSpecWithTemplate: {
144 const TagType *Tag = NNS->getAsType()->getAs<TagType>();
145 assert(Tag && "Non-tag type in nested-name-specifier");
146 return Tag->getDecl();
147 }
148
149 case NestedNameSpecifier::Global:
150 return Context.getTranslationUnitDecl();
151
152 case NestedNameSpecifier::Super:
153 return NNS->getAsRecordDecl();
154 }
155
156 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
157 }
158
isDependentScopeSpecifier(const CXXScopeSpec & SS)159 bool Sema::isDependentScopeSpecifier(const CXXScopeSpec &SS) {
160 if (!SS.isSet() || SS.isInvalid())
161 return false;
162
163 return SS.getScopeRep()->isDependent();
164 }
165
166 /// \brief If the given nested name specifier refers to the current
167 /// instantiation, return the declaration that corresponds to that
168 /// current instantiation (C++0x [temp.dep.type]p1).
169 ///
170 /// \param NNS a dependent nested name specifier.
getCurrentInstantiationOf(NestedNameSpecifier * NNS)171 CXXRecordDecl *Sema::getCurrentInstantiationOf(NestedNameSpecifier *NNS) {
172 assert(getLangOpts().CPlusPlus && "Only callable in C++");
173 assert(NNS->isDependent() && "Only dependent nested-name-specifier allowed");
174
175 if (!NNS->getAsType())
176 return nullptr;
177
178 QualType T = QualType(NNS->getAsType(), 0);
179 return ::getCurrentInstantiationOf(T, CurContext);
180 }
181
182 /// \brief Require that the context specified by SS be complete.
183 ///
184 /// If SS refers to a type, this routine checks whether the type is
185 /// complete enough (or can be made complete enough) for name lookup
186 /// into the DeclContext. A type that is not yet completed can be
187 /// considered "complete enough" if it is a class/struct/union/enum
188 /// that is currently being defined. Or, if we have a type that names
189 /// a class template specialization that is not a complete type, we
190 /// will attempt to instantiate that class template.
RequireCompleteDeclContext(CXXScopeSpec & SS,DeclContext * DC)191 bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
192 DeclContext *DC) {
193 assert(DC && "given null context");
194
195 TagDecl *tag = dyn_cast<TagDecl>(DC);
196
197 // If this is a dependent type, then we consider it complete.
198 if (!tag || tag->isDependentContext())
199 return false;
200
201 // If we're currently defining this type, then lookup into the
202 // type is okay: don't complain that it isn't complete yet.
203 QualType type = Context.getTypeDeclType(tag);
204 const TagType *tagType = type->getAs<TagType>();
205 if (tagType && tagType->isBeingDefined())
206 return false;
207
208 SourceLocation loc = SS.getLastQualifierNameLoc();
209 if (loc.isInvalid()) loc = SS.getRange().getBegin();
210
211 // The type must be complete.
212 if (RequireCompleteType(loc, type, diag::err_incomplete_nested_name_spec,
213 SS.getRange())) {
214 SS.SetInvalid(SS.getRange());
215 return true;
216 }
217
218 // Fixed enum types are complete, but they aren't valid as scopes
219 // until we see a definition, so awkwardly pull out this special
220 // case.
221 const EnumType *enumType = dyn_cast_or_null<EnumType>(tagType);
222 if (!enumType || enumType->getDecl()->isCompleteDefinition())
223 return false;
224
225 // Try to instantiate the definition, if this is a specialization of an
226 // enumeration temploid.
227 EnumDecl *ED = enumType->getDecl();
228 if (EnumDecl *Pattern = ED->getInstantiatedFromMemberEnum()) {
229 MemberSpecializationInfo *MSI = ED->getMemberSpecializationInfo();
230 if (MSI->getTemplateSpecializationKind() != TSK_ExplicitSpecialization) {
231 if (InstantiateEnum(loc, ED, Pattern, getTemplateInstantiationArgs(ED),
232 TSK_ImplicitInstantiation)) {
233 SS.SetInvalid(SS.getRange());
234 return true;
235 }
236 return false;
237 }
238 }
239
240 Diag(loc, diag::err_incomplete_nested_name_spec)
241 << type << SS.getRange();
242 SS.SetInvalid(SS.getRange());
243 return true;
244 }
245
ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc,CXXScopeSpec & SS)246 bool Sema::ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc,
247 CXXScopeSpec &SS) {
248 SS.MakeGlobal(Context, CCLoc);
249 return false;
250 }
251
ActOnSuperScopeSpecifier(SourceLocation SuperLoc,SourceLocation ColonColonLoc,CXXScopeSpec & SS)252 bool Sema::ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
253 SourceLocation ColonColonLoc,
254 CXXScopeSpec &SS) {
255 CXXRecordDecl *RD = nullptr;
256 for (Scope *S = getCurScope(); S; S = S->getParent()) {
257 if (S->isFunctionScope()) {
258 if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(S->getEntity()))
259 RD = MD->getParent();
260 break;
261 }
262 if (S->isClassScope()) {
263 RD = cast<CXXRecordDecl>(S->getEntity());
264 break;
265 }
266 }
267
268 if (!RD) {
269 Diag(SuperLoc, diag::err_invalid_super_scope);
270 return true;
271 } else if (RD->isLambda()) {
272 Diag(SuperLoc, diag::err_super_in_lambda_unsupported);
273 return true;
274 } else if (RD->getNumBases() == 0) {
275 Diag(SuperLoc, diag::err_no_base_classes) << RD->getName();
276 return true;
277 }
278
279 SS.MakeSuper(Context, RD, SuperLoc, ColonColonLoc);
280 return false;
281 }
282
283 /// \brief Determines whether the given declaration is an valid acceptable
284 /// result for name lookup of a nested-name-specifier.
isAcceptableNestedNameSpecifier(const NamedDecl * SD)285 bool Sema::isAcceptableNestedNameSpecifier(const NamedDecl *SD) {
286 if (!SD)
287 return false;
288
289 // Namespace and namespace aliases are fine.
290 if (isa<NamespaceDecl>(SD) || isa<NamespaceAliasDecl>(SD))
291 return true;
292
293 if (!isa<TypeDecl>(SD))
294 return false;
295
296 // Determine whether we have a class (or, in C++11, an enum) or
297 // a typedef thereof. If so, build the nested-name-specifier.
298 QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
299 if (T->isDependentType())
300 return true;
301 else if (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) {
302 if (TD->getUnderlyingType()->isRecordType() ||
303 (Context.getLangOpts().CPlusPlus11 &&
304 TD->getUnderlyingType()->isEnumeralType()))
305 return true;
306 } else if (isa<RecordDecl>(SD) ||
307 (Context.getLangOpts().CPlusPlus11 && isa<EnumDecl>(SD)))
308 return true;
309
310 return false;
311 }
312
313 /// \brief If the given nested-name-specifier begins with a bare identifier
314 /// (e.g., Base::), perform name lookup for that identifier as a
315 /// nested-name-specifier within the given scope, and return the result of that
316 /// name lookup.
FindFirstQualifierInScope(Scope * S,NestedNameSpecifier * NNS)317 NamedDecl *Sema::FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS) {
318 if (!S || !NNS)
319 return nullptr;
320
321 while (NNS->getPrefix())
322 NNS = NNS->getPrefix();
323
324 if (NNS->getKind() != NestedNameSpecifier::Identifier)
325 return nullptr;
326
327 LookupResult Found(*this, NNS->getAsIdentifier(), SourceLocation(),
328 LookupNestedNameSpecifierName);
329 LookupName(Found, S);
330 assert(!Found.isAmbiguous() && "Cannot handle ambiguities here yet");
331
332 if (!Found.isSingleResult())
333 return nullptr;
334
335 NamedDecl *Result = Found.getFoundDecl();
336 if (isAcceptableNestedNameSpecifier(Result))
337 return Result;
338
339 return nullptr;
340 }
341
isNonTypeNestedNameSpecifier(Scope * S,CXXScopeSpec & SS,SourceLocation IdLoc,IdentifierInfo & II,ParsedType ObjectTypePtr)342 bool Sema::isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
343 SourceLocation IdLoc,
344 IdentifierInfo &II,
345 ParsedType ObjectTypePtr) {
346 QualType ObjectType = GetTypeFromParser(ObjectTypePtr);
347 LookupResult Found(*this, &II, IdLoc, LookupNestedNameSpecifierName);
348
349 // Determine where to perform name lookup
350 DeclContext *LookupCtx = nullptr;
351 bool isDependent = false;
352 if (!ObjectType.isNull()) {
353 // This nested-name-specifier occurs in a member access expression, e.g.,
354 // x->B::f, and we are looking into the type of the object.
355 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
356 LookupCtx = computeDeclContext(ObjectType);
357 isDependent = ObjectType->isDependentType();
358 } else if (SS.isSet()) {
359 // This nested-name-specifier occurs after another nested-name-specifier,
360 // so long into the context associated with the prior nested-name-specifier.
361 LookupCtx = computeDeclContext(SS, false);
362 isDependent = isDependentScopeSpecifier(SS);
363 Found.setContextRange(SS.getRange());
364 }
365
366 if (LookupCtx) {
367 // Perform "qualified" name lookup into the declaration context we
368 // computed, which is either the type of the base of a member access
369 // expression or the declaration context associated with a prior
370 // nested-name-specifier.
371
372 // The declaration context must be complete.
373 if (!LookupCtx->isDependentContext() &&
374 RequireCompleteDeclContext(SS, LookupCtx))
375 return false;
376
377 LookupQualifiedName(Found, LookupCtx);
378 } else if (isDependent) {
379 return false;
380 } else {
381 LookupName(Found, S);
382 }
383 Found.suppressDiagnostics();
384
385 if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
386 return isa<NamespaceDecl>(ND) || isa<NamespaceAliasDecl>(ND);
387
388 return false;
389 }
390
391 namespace {
392
393 // Callback to only accept typo corrections that can be a valid C++ member
394 // intializer: either a non-static field member or a base class.
395 class NestedNameSpecifierValidatorCCC : public CorrectionCandidateCallback {
396 public:
NestedNameSpecifierValidatorCCC(Sema & SRef)397 explicit NestedNameSpecifierValidatorCCC(Sema &SRef)
398 : SRef(SRef) {}
399
ValidateCandidate(const TypoCorrection & candidate)400 bool ValidateCandidate(const TypoCorrection &candidate) override {
401 return SRef.isAcceptableNestedNameSpecifier(candidate.getCorrectionDecl());
402 }
403
404 private:
405 Sema &SRef;
406 };
407
408 }
409
410 /// \brief Build a new nested-name-specifier for "identifier::", as described
411 /// by ActOnCXXNestedNameSpecifier.
412 ///
413 /// \param S Scope in which the nested-name-specifier occurs.
414 /// \param Identifier Identifier in the sequence "identifier" "::".
415 /// \param IdentifierLoc Location of the \p Identifier.
416 /// \param CCLoc Location of "::" following Identifier.
417 /// \param ObjectType Type of postfix expression if the nested-name-specifier
418 /// occurs in construct like: <tt>ptr->nns::f</tt>.
419 /// \param EnteringContext If true, enter the context specified by the
420 /// nested-name-specifier.
421 /// \param SS Optional nested name specifier preceding the identifier.
422 /// \param ScopeLookupResult Provides the result of name lookup within the
423 /// scope of the nested-name-specifier that was computed at template
424 /// definition time.
425 /// \param ErrorRecoveryLookup Specifies if the method is called to improve
426 /// error recovery and what kind of recovery is performed.
427 /// \param IsCorrectedToColon If not null, suggestion of replace '::' -> ':'
428 /// are allowed. The bool value pointed by this parameter is set to
429 /// 'true' if the identifier is treated as if it was followed by ':',
430 /// not '::'.
431 ///
432 /// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
433 /// that it contains an extra parameter \p ScopeLookupResult, which provides
434 /// the result of name lookup within the scope of the nested-name-specifier
435 /// that was computed at template definition time.
436 ///
437 /// If ErrorRecoveryLookup is true, then this call is used to improve error
438 /// recovery. This means that it should not emit diagnostics, it should
439 /// just return true on failure. It also means it should only return a valid
440 /// scope if it *knows* that the result is correct. It should not return in a
441 /// dependent context, for example. Nor will it extend \p SS with the scope
442 /// specifier.
BuildCXXNestedNameSpecifier(Scope * S,IdentifierInfo & Identifier,SourceLocation IdentifierLoc,SourceLocation CCLoc,QualType ObjectType,bool EnteringContext,CXXScopeSpec & SS,NamedDecl * ScopeLookupResult,bool ErrorRecoveryLookup,bool * IsCorrectedToColon)443 bool Sema::BuildCXXNestedNameSpecifier(Scope *S,
444 IdentifierInfo &Identifier,
445 SourceLocation IdentifierLoc,
446 SourceLocation CCLoc,
447 QualType ObjectType,
448 bool EnteringContext,
449 CXXScopeSpec &SS,
450 NamedDecl *ScopeLookupResult,
451 bool ErrorRecoveryLookup,
452 bool *IsCorrectedToColon) {
453 LookupResult Found(*this, &Identifier, IdentifierLoc,
454 LookupNestedNameSpecifierName);
455
456 // Determine where to perform name lookup
457 DeclContext *LookupCtx = nullptr;
458 bool isDependent = false;
459 if (IsCorrectedToColon)
460 *IsCorrectedToColon = false;
461 if (!ObjectType.isNull()) {
462 // This nested-name-specifier occurs in a member access expression, e.g.,
463 // x->B::f, and we are looking into the type of the object.
464 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
465 LookupCtx = computeDeclContext(ObjectType);
466 isDependent = ObjectType->isDependentType();
467 } else if (SS.isSet()) {
468 // This nested-name-specifier occurs after another nested-name-specifier,
469 // so look into the context associated with the prior nested-name-specifier.
470 LookupCtx = computeDeclContext(SS, EnteringContext);
471 isDependent = isDependentScopeSpecifier(SS);
472 Found.setContextRange(SS.getRange());
473 }
474
475 bool ObjectTypeSearchedInScope = false;
476 if (LookupCtx) {
477 // Perform "qualified" name lookup into the declaration context we
478 // computed, which is either the type of the base of a member access
479 // expression or the declaration context associated with a prior
480 // nested-name-specifier.
481
482 // The declaration context must be complete.
483 if (!LookupCtx->isDependentContext() &&
484 RequireCompleteDeclContext(SS, LookupCtx))
485 return true;
486
487 LookupQualifiedName(Found, LookupCtx);
488
489 if (!ObjectType.isNull() && Found.empty()) {
490 // C++ [basic.lookup.classref]p4:
491 // If the id-expression in a class member access is a qualified-id of
492 // the form
493 //
494 // class-name-or-namespace-name::...
495 //
496 // the class-name-or-namespace-name following the . or -> operator is
497 // looked up both in the context of the entire postfix-expression and in
498 // the scope of the class of the object expression. If the name is found
499 // only in the scope of the class of the object expression, the name
500 // shall refer to a class-name. If the name is found only in the
501 // context of the entire postfix-expression, the name shall refer to a
502 // class-name or namespace-name. [...]
503 //
504 // Qualified name lookup into a class will not find a namespace-name,
505 // so we do not need to diagnose that case specifically. However,
506 // this qualified name lookup may find nothing. In that case, perform
507 // unqualified name lookup in the given scope (if available) or
508 // reconstruct the result from when name lookup was performed at template
509 // definition time.
510 if (S)
511 LookupName(Found, S);
512 else if (ScopeLookupResult)
513 Found.addDecl(ScopeLookupResult);
514
515 ObjectTypeSearchedInScope = true;
516 }
517 } else if (!isDependent) {
518 // Perform unqualified name lookup in the current scope.
519 LookupName(Found, S);
520 }
521
522 // If we performed lookup into a dependent context and did not find anything,
523 // that's fine: just build a dependent nested-name-specifier.
524 if (Found.empty() && isDependent &&
525 !(LookupCtx && LookupCtx->isRecord() &&
526 (!cast<CXXRecordDecl>(LookupCtx)->hasDefinition() ||
527 !cast<CXXRecordDecl>(LookupCtx)->hasAnyDependentBases()))) {
528 // Don't speculate if we're just trying to improve error recovery.
529 if (ErrorRecoveryLookup)
530 return true;
531
532 // We were not able to compute the declaration context for a dependent
533 // base object type or prior nested-name-specifier, so this
534 // nested-name-specifier refers to an unknown specialization. Just build
535 // a dependent nested-name-specifier.
536 SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc);
537 return false;
538 }
539
540 // FIXME: Deal with ambiguities cleanly.
541
542 if (Found.empty() && !ErrorRecoveryLookup) {
543 // If identifier is not found as class-name-or-namespace-name, but is found
544 // as other entity, don't look for typos.
545 LookupResult R(*this, Found.getLookupNameInfo(), LookupOrdinaryName);
546 if (LookupCtx)
547 LookupQualifiedName(R, LookupCtx);
548 else if (S && !isDependent)
549 LookupName(R, S);
550 if (!R.empty()) {
551 // The identifier is found in ordinary lookup. If correction to colon is
552 // allowed, suggest replacement to ':'.
553 if (IsCorrectedToColon) {
554 *IsCorrectedToColon = true;
555 Diag(CCLoc, diag::err_nested_name_spec_is_not_class)
556 << &Identifier << getLangOpts().CPlusPlus
557 << FixItHint::CreateReplacement(CCLoc, ":");
558 if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
559 Diag(ND->getLocation(), diag::note_declared_at);
560 return true;
561 }
562 // Replacement '::' -> ':' is not allowed, just issue respective error.
563 Diag(R.getNameLoc(), diag::err_expected_class_or_namespace)
564 << &Identifier << getLangOpts().CPlusPlus;
565 if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
566 Diag(ND->getLocation(), diag::note_entity_declared_at) << &Identifier;
567 return true;
568 }
569 }
570
571 if (Found.empty() && !ErrorRecoveryLookup && !getLangOpts().MSVCCompat) {
572 // We haven't found anything, and we're not recovering from a
573 // different kind of error, so look for typos.
574 DeclarationName Name = Found.getLookupName();
575 Found.clear();
576 if (TypoCorrection Corrected = CorrectTypo(
577 Found.getLookupNameInfo(), Found.getLookupKind(), S, &SS,
578 llvm::make_unique<NestedNameSpecifierValidatorCCC>(*this),
579 CTK_ErrorRecovery, LookupCtx, EnteringContext)) {
580 if (LookupCtx) {
581 bool DroppedSpecifier =
582 Corrected.WillReplaceSpecifier() &&
583 Name.getAsString() == Corrected.getAsString(getLangOpts());
584 if (DroppedSpecifier)
585 SS.clear();
586 diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest)
587 << Name << LookupCtx << DroppedSpecifier
588 << SS.getRange());
589 } else
590 diagnoseTypo(Corrected, PDiag(diag::err_undeclared_var_use_suggest)
591 << Name);
592
593 if (NamedDecl *ND = Corrected.getCorrectionDecl())
594 Found.addDecl(ND);
595 Found.setLookupName(Corrected.getCorrection());
596 } else {
597 Found.setLookupName(&Identifier);
598 }
599 }
600
601 NamedDecl *SD = Found.getAsSingle<NamedDecl>();
602 if (isAcceptableNestedNameSpecifier(SD)) {
603 if (!ObjectType.isNull() && !ObjectTypeSearchedInScope &&
604 !getLangOpts().CPlusPlus11) {
605 // C++03 [basic.lookup.classref]p4:
606 // [...] If the name is found in both contexts, the
607 // class-name-or-namespace-name shall refer to the same entity.
608 //
609 // We already found the name in the scope of the object. Now, look
610 // into the current scope (the scope of the postfix-expression) to
611 // see if we can find the same name there. As above, if there is no
612 // scope, reconstruct the result from the template instantiation itself.
613 //
614 // Note that C++11 does *not* perform this redundant lookup.
615 NamedDecl *OuterDecl;
616 if (S) {
617 LookupResult FoundOuter(*this, &Identifier, IdentifierLoc,
618 LookupNestedNameSpecifierName);
619 LookupName(FoundOuter, S);
620 OuterDecl = FoundOuter.getAsSingle<NamedDecl>();
621 } else
622 OuterDecl = ScopeLookupResult;
623
624 if (isAcceptableNestedNameSpecifier(OuterDecl) &&
625 OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() &&
626 (!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) ||
627 !Context.hasSameType(
628 Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)),
629 Context.getTypeDeclType(cast<TypeDecl>(SD))))) {
630 if (ErrorRecoveryLookup)
631 return true;
632
633 Diag(IdentifierLoc,
634 diag::err_nested_name_member_ref_lookup_ambiguous)
635 << &Identifier;
636 Diag(SD->getLocation(), diag::note_ambig_member_ref_object_type)
637 << ObjectType;
638 Diag(OuterDecl->getLocation(), diag::note_ambig_member_ref_scope);
639
640 // Fall through so that we'll pick the name we found in the object
641 // type, since that's probably what the user wanted anyway.
642 }
643 }
644
645 if (auto *TD = dyn_cast_or_null<TypedefNameDecl>(SD))
646 MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
647
648 // If we're just performing this lookup for error-recovery purposes,
649 // don't extend the nested-name-specifier. Just return now.
650 if (ErrorRecoveryLookup)
651 return false;
652
653 // The use of a nested name specifier may trigger deprecation warnings.
654 DiagnoseUseOfDecl(SD, CCLoc);
655
656
657 if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD)) {
658 SS.Extend(Context, Namespace, IdentifierLoc, CCLoc);
659 return false;
660 }
661
662 if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD)) {
663 SS.Extend(Context, Alias, IdentifierLoc, CCLoc);
664 return false;
665 }
666
667 QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
668 TypeLocBuilder TLB;
669 if (isa<InjectedClassNameType>(T)) {
670 InjectedClassNameTypeLoc InjectedTL
671 = TLB.push<InjectedClassNameTypeLoc>(T);
672 InjectedTL.setNameLoc(IdentifierLoc);
673 } else if (isa<RecordType>(T)) {
674 RecordTypeLoc RecordTL = TLB.push<RecordTypeLoc>(T);
675 RecordTL.setNameLoc(IdentifierLoc);
676 } else if (isa<TypedefType>(T)) {
677 TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(T);
678 TypedefTL.setNameLoc(IdentifierLoc);
679 } else if (isa<EnumType>(T)) {
680 EnumTypeLoc EnumTL = TLB.push<EnumTypeLoc>(T);
681 EnumTL.setNameLoc(IdentifierLoc);
682 } else if (isa<TemplateTypeParmType>(T)) {
683 TemplateTypeParmTypeLoc TemplateTypeTL
684 = TLB.push<TemplateTypeParmTypeLoc>(T);
685 TemplateTypeTL.setNameLoc(IdentifierLoc);
686 } else if (isa<UnresolvedUsingType>(T)) {
687 UnresolvedUsingTypeLoc UnresolvedTL
688 = TLB.push<UnresolvedUsingTypeLoc>(T);
689 UnresolvedTL.setNameLoc(IdentifierLoc);
690 } else if (isa<SubstTemplateTypeParmType>(T)) {
691 SubstTemplateTypeParmTypeLoc TL
692 = TLB.push<SubstTemplateTypeParmTypeLoc>(T);
693 TL.setNameLoc(IdentifierLoc);
694 } else if (isa<SubstTemplateTypeParmPackType>(T)) {
695 SubstTemplateTypeParmPackTypeLoc TL
696 = TLB.push<SubstTemplateTypeParmPackTypeLoc>(T);
697 TL.setNameLoc(IdentifierLoc);
698 } else {
699 llvm_unreachable("Unhandled TypeDecl node in nested-name-specifier");
700 }
701
702 if (T->isEnumeralType())
703 Diag(IdentifierLoc, diag::warn_cxx98_compat_enum_nested_name_spec);
704
705 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
706 CCLoc);
707 return false;
708 }
709
710 // Otherwise, we have an error case. If we don't want diagnostics, just
711 // return an error now.
712 if (ErrorRecoveryLookup)
713 return true;
714
715 // If we didn't find anything during our lookup, try again with
716 // ordinary name lookup, which can help us produce better error
717 // messages.
718 if (Found.empty()) {
719 Found.clear(LookupOrdinaryName);
720 LookupName(Found, S);
721 }
722
723 // In Microsoft mode, if we are within a templated function and we can't
724 // resolve Identifier, then extend the SS with Identifier. This will have
725 // the effect of resolving Identifier during template instantiation.
726 // The goal is to be able to resolve a function call whose
727 // nested-name-specifier is located inside a dependent base class.
728 // Example:
729 //
730 // class C {
731 // public:
732 // static void foo2() { }
733 // };
734 // template <class T> class A { public: typedef C D; };
735 //
736 // template <class T> class B : public A<T> {
737 // public:
738 // void foo() { D::foo2(); }
739 // };
740 if (getLangOpts().MSVCCompat) {
741 DeclContext *DC = LookupCtx ? LookupCtx : CurContext;
742 if (DC->isDependentContext() && DC->isFunctionOrMethod()) {
743 CXXRecordDecl *ContainingClass = dyn_cast<CXXRecordDecl>(DC->getParent());
744 if (ContainingClass && ContainingClass->hasAnyDependentBases()) {
745 Diag(IdentifierLoc, diag::ext_undeclared_unqual_id_with_dependent_base)
746 << &Identifier << ContainingClass;
747 SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc);
748 return false;
749 }
750 }
751 }
752
753 if (!Found.empty()) {
754 if (TypeDecl *TD = Found.getAsSingle<TypeDecl>())
755 Diag(IdentifierLoc, diag::err_expected_class_or_namespace)
756 << QualType(TD->getTypeForDecl(), 0) << getLangOpts().CPlusPlus;
757 else {
758 Diag(IdentifierLoc, diag::err_expected_class_or_namespace)
759 << &Identifier << getLangOpts().CPlusPlus;
760 if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
761 Diag(ND->getLocation(), diag::note_entity_declared_at) << &Identifier;
762 }
763 } else if (SS.isSet())
764 Diag(IdentifierLoc, diag::err_no_member) << &Identifier << LookupCtx
765 << SS.getRange();
766 else
767 Diag(IdentifierLoc, diag::err_undeclared_var_use) << &Identifier;
768
769 return true;
770 }
771
ActOnCXXNestedNameSpecifier(Scope * S,IdentifierInfo & Identifier,SourceLocation IdentifierLoc,SourceLocation CCLoc,ParsedType ObjectType,bool EnteringContext,CXXScopeSpec & SS,bool ErrorRecoveryLookup,bool * IsCorrectedToColon)772 bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
773 IdentifierInfo &Identifier,
774 SourceLocation IdentifierLoc,
775 SourceLocation CCLoc,
776 ParsedType ObjectType,
777 bool EnteringContext,
778 CXXScopeSpec &SS,
779 bool ErrorRecoveryLookup,
780 bool *IsCorrectedToColon) {
781 if (SS.isInvalid())
782 return true;
783
784 return BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, CCLoc,
785 GetTypeFromParser(ObjectType),
786 EnteringContext, SS,
787 /*ScopeLookupResult=*/nullptr, false,
788 IsCorrectedToColon);
789 }
790
ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec & SS,const DeclSpec & DS,SourceLocation ColonColonLoc)791 bool Sema::ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
792 const DeclSpec &DS,
793 SourceLocation ColonColonLoc) {
794 if (SS.isInvalid() || DS.getTypeSpecType() == DeclSpec::TST_error)
795 return true;
796
797 assert(DS.getTypeSpecType() == DeclSpec::TST_decltype);
798
799 QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
800 if (!T->isDependentType() && !T->getAs<TagType>()) {
801 Diag(DS.getTypeSpecTypeLoc(), diag::err_expected_class_or_namespace)
802 << T << getLangOpts().CPlusPlus;
803 return true;
804 }
805
806 TypeLocBuilder TLB;
807 DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T);
808 DecltypeTL.setNameLoc(DS.getTypeSpecTypeLoc());
809 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
810 ColonColonLoc);
811 return false;
812 }
813
814 /// IsInvalidUnlessNestedName - This method is used for error recovery
815 /// purposes to determine whether the specified identifier is only valid as
816 /// a nested name specifier, for example a namespace name. It is
817 /// conservatively correct to always return false from this method.
818 ///
819 /// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
IsInvalidUnlessNestedName(Scope * S,CXXScopeSpec & SS,IdentifierInfo & Identifier,SourceLocation IdentifierLoc,SourceLocation ColonLoc,ParsedType ObjectType,bool EnteringContext)820 bool Sema::IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
821 IdentifierInfo &Identifier,
822 SourceLocation IdentifierLoc,
823 SourceLocation ColonLoc,
824 ParsedType ObjectType,
825 bool EnteringContext) {
826 if (SS.isInvalid())
827 return false;
828
829 return !BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, ColonLoc,
830 GetTypeFromParser(ObjectType),
831 EnteringContext, SS,
832 /*ScopeLookupResult=*/nullptr, true);
833 }
834
ActOnCXXNestedNameSpecifier(Scope * S,CXXScopeSpec & SS,SourceLocation TemplateKWLoc,TemplateTy Template,SourceLocation TemplateNameLoc,SourceLocation LAngleLoc,ASTTemplateArgsPtr TemplateArgsIn,SourceLocation RAngleLoc,SourceLocation CCLoc,bool EnteringContext)835 bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
836 CXXScopeSpec &SS,
837 SourceLocation TemplateKWLoc,
838 TemplateTy Template,
839 SourceLocation TemplateNameLoc,
840 SourceLocation LAngleLoc,
841 ASTTemplateArgsPtr TemplateArgsIn,
842 SourceLocation RAngleLoc,
843 SourceLocation CCLoc,
844 bool EnteringContext) {
845 if (SS.isInvalid())
846 return true;
847
848 // Translate the parser's template argument list in our AST format.
849 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
850 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
851
852 DependentTemplateName *DTN = Template.get().getAsDependentTemplateName();
853 if (DTN && DTN->isIdentifier()) {
854 // Handle a dependent template specialization for which we cannot resolve
855 // the template name.
856 assert(DTN->getQualifier() == SS.getScopeRep());
857 QualType T = Context.getDependentTemplateSpecializationType(ETK_None,
858 DTN->getQualifier(),
859 DTN->getIdentifier(),
860 TemplateArgs);
861
862 // Create source-location information for this type.
863 TypeLocBuilder Builder;
864 DependentTemplateSpecializationTypeLoc SpecTL
865 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
866 SpecTL.setElaboratedKeywordLoc(SourceLocation());
867 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
868 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
869 SpecTL.setTemplateNameLoc(TemplateNameLoc);
870 SpecTL.setLAngleLoc(LAngleLoc);
871 SpecTL.setRAngleLoc(RAngleLoc);
872 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
873 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
874
875 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
876 CCLoc);
877 return false;
878 }
879
880 TemplateDecl *TD = Template.get().getAsTemplateDecl();
881 if (Template.get().getAsOverloadedTemplate() || DTN ||
882 isa<FunctionTemplateDecl>(TD) || isa<VarTemplateDecl>(TD)) {
883 SourceRange R(TemplateNameLoc, RAngleLoc);
884 if (SS.getRange().isValid())
885 R.setBegin(SS.getRange().getBegin());
886
887 Diag(CCLoc, diag::err_non_type_template_in_nested_name_specifier)
888 << (TD && isa<VarTemplateDecl>(TD)) << Template.get() << R;
889 NoteAllFoundTemplates(Template.get());
890 return true;
891 }
892
893 // We were able to resolve the template name to an actual template.
894 // Build an appropriate nested-name-specifier.
895 QualType T = CheckTemplateIdType(Template.get(), TemplateNameLoc,
896 TemplateArgs);
897 if (T.isNull())
898 return true;
899
900 // Alias template specializations can produce types which are not valid
901 // nested name specifiers.
902 if (!T->isDependentType() && !T->getAs<TagType>()) {
903 Diag(TemplateNameLoc, diag::err_nested_name_spec_non_tag) << T;
904 NoteAllFoundTemplates(Template.get());
905 return true;
906 }
907
908 // Provide source-location information for the template specialization type.
909 TypeLocBuilder Builder;
910 TemplateSpecializationTypeLoc SpecTL
911 = Builder.push<TemplateSpecializationTypeLoc>(T);
912 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
913 SpecTL.setTemplateNameLoc(TemplateNameLoc);
914 SpecTL.setLAngleLoc(LAngleLoc);
915 SpecTL.setRAngleLoc(RAngleLoc);
916 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
917 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
918
919
920 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
921 CCLoc);
922 return false;
923 }
924
925 namespace {
926 /// \brief A structure that stores a nested-name-specifier annotation,
927 /// including both the nested-name-specifier
928 struct NestedNameSpecifierAnnotation {
929 NestedNameSpecifier *NNS;
930 };
931 }
932
SaveNestedNameSpecifierAnnotation(CXXScopeSpec & SS)933 void *Sema::SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS) {
934 if (SS.isEmpty() || SS.isInvalid())
935 return nullptr;
936
937 void *Mem = Context.Allocate((sizeof(NestedNameSpecifierAnnotation) +
938 SS.location_size()),
939 llvm::alignOf<NestedNameSpecifierAnnotation>());
940 NestedNameSpecifierAnnotation *Annotation
941 = new (Mem) NestedNameSpecifierAnnotation;
942 Annotation->NNS = SS.getScopeRep();
943 memcpy(Annotation + 1, SS.location_data(), SS.location_size());
944 return Annotation;
945 }
946
RestoreNestedNameSpecifierAnnotation(void * AnnotationPtr,SourceRange AnnotationRange,CXXScopeSpec & SS)947 void Sema::RestoreNestedNameSpecifierAnnotation(void *AnnotationPtr,
948 SourceRange AnnotationRange,
949 CXXScopeSpec &SS) {
950 if (!AnnotationPtr) {
951 SS.SetInvalid(AnnotationRange);
952 return;
953 }
954
955 NestedNameSpecifierAnnotation *Annotation
956 = static_cast<NestedNameSpecifierAnnotation *>(AnnotationPtr);
957 SS.Adopt(NestedNameSpecifierLoc(Annotation->NNS, Annotation + 1));
958 }
959
ShouldEnterDeclaratorScope(Scope * S,const CXXScopeSpec & SS)960 bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
961 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
962
963 NestedNameSpecifier *Qualifier = SS.getScopeRep();
964
965 // There are only two places a well-formed program may qualify a
966 // declarator: first, when defining a namespace or class member
967 // out-of-line, and second, when naming an explicitly-qualified
968 // friend function. The latter case is governed by
969 // C++03 [basic.lookup.unqual]p10:
970 // In a friend declaration naming a member function, a name used
971 // in the function declarator and not part of a template-argument
972 // in a template-id is first looked up in the scope of the member
973 // function's class. If it is not found, or if the name is part of
974 // a template-argument in a template-id, the look up is as
975 // described for unqualified names in the definition of the class
976 // granting friendship.
977 // i.e. we don't push a scope unless it's a class member.
978
979 switch (Qualifier->getKind()) {
980 case NestedNameSpecifier::Global:
981 case NestedNameSpecifier::Namespace:
982 case NestedNameSpecifier::NamespaceAlias:
983 // These are always namespace scopes. We never want to enter a
984 // namespace scope from anything but a file context.
985 return CurContext->getRedeclContext()->isFileContext();
986
987 case NestedNameSpecifier::Identifier:
988 case NestedNameSpecifier::TypeSpec:
989 case NestedNameSpecifier::TypeSpecWithTemplate:
990 case NestedNameSpecifier::Super:
991 // These are never namespace scopes.
992 return true;
993 }
994
995 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
996 }
997
998 /// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
999 /// scope or nested-name-specifier) is parsed, part of a declarator-id.
1000 /// After this method is called, according to [C++ 3.4.3p3], names should be
1001 /// looked up in the declarator-id's scope, until the declarator is parsed and
1002 /// ActOnCXXExitDeclaratorScope is called.
1003 /// The 'SS' should be a non-empty valid CXXScopeSpec.
ActOnCXXEnterDeclaratorScope(Scope * S,CXXScopeSpec & SS)1004 bool Sema::ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS) {
1005 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1006
1007 if (SS.isInvalid()) return true;
1008
1009 DeclContext *DC = computeDeclContext(SS, true);
1010 if (!DC) return true;
1011
1012 // Before we enter a declarator's context, we need to make sure that
1013 // it is a complete declaration context.
1014 if (!DC->isDependentContext() && RequireCompleteDeclContext(SS, DC))
1015 return true;
1016
1017 EnterDeclaratorContext(S, DC);
1018
1019 // Rebuild the nested name specifier for the new scope.
1020 if (DC->isDependentContext())
1021 RebuildNestedNameSpecifierInCurrentInstantiation(SS);
1022
1023 return false;
1024 }
1025
1026 /// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
1027 /// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
1028 /// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
1029 /// Used to indicate that names should revert to being looked up in the
1030 /// defining scope.
ActOnCXXExitDeclaratorScope(Scope * S,const CXXScopeSpec & SS)1031 void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
1032 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1033 if (SS.isInvalid())
1034 return;
1035 assert(!SS.isInvalid() && computeDeclContext(SS, true) &&
1036 "exiting declarator scope we never really entered");
1037 ExitDeclaratorContext(S);
1038 }
1039