SemaCXXScopeSpec.cpp revision 296417
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" 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 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). 55DeclContext *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). 76DeclContext *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 159bool 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. 171CXXRecordDecl *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. 191bool 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 // FIXME: The definition might not be visible; complain if it is not. 222 const EnumType *enumType = dyn_cast_or_null<EnumType>(tagType); 223 if (!enumType || enumType->getDecl()->isCompleteDefinition()) 224 return false; 225 226 // Try to instantiate the definition, if this is a specialization of an 227 // enumeration temploid. 228 EnumDecl *ED = enumType->getDecl(); 229 if (EnumDecl *Pattern = ED->getInstantiatedFromMemberEnum()) { 230 MemberSpecializationInfo *MSI = ED->getMemberSpecializationInfo(); 231 if (MSI->getTemplateSpecializationKind() != TSK_ExplicitSpecialization) { 232 if (InstantiateEnum(loc, ED, Pattern, getTemplateInstantiationArgs(ED), 233 TSK_ImplicitInstantiation)) { 234 SS.SetInvalid(SS.getRange()); 235 return true; 236 } 237 return false; 238 } 239 } 240 241 Diag(loc, diag::err_incomplete_nested_name_spec) 242 << type << SS.getRange(); 243 SS.SetInvalid(SS.getRange()); 244 return true; 245} 246 247bool Sema::ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc, 248 CXXScopeSpec &SS) { 249 SS.MakeGlobal(Context, CCLoc); 250 return false; 251} 252 253bool Sema::ActOnSuperScopeSpecifier(SourceLocation SuperLoc, 254 SourceLocation ColonColonLoc, 255 CXXScopeSpec &SS) { 256 CXXRecordDecl *RD = nullptr; 257 for (Scope *S = getCurScope(); S; S = S->getParent()) { 258 if (S->isFunctionScope()) { 259 if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(S->getEntity())) 260 RD = MD->getParent(); 261 break; 262 } 263 if (S->isClassScope()) { 264 RD = cast<CXXRecordDecl>(S->getEntity()); 265 break; 266 } 267 } 268 269 if (!RD) { 270 Diag(SuperLoc, diag::err_invalid_super_scope); 271 return true; 272 } else if (RD->isLambda()) { 273 Diag(SuperLoc, diag::err_super_in_lambda_unsupported); 274 return true; 275 } else if (RD->getNumBases() == 0) { 276 Diag(SuperLoc, diag::err_no_base_classes) << RD->getName(); 277 return true; 278 } 279 280 SS.MakeSuper(Context, RD, SuperLoc, ColonColonLoc); 281 return false; 282} 283 284/// \brief Determines whether the given declaration is an valid acceptable 285/// result for name lookup of a nested-name-specifier. 286/// \param SD Declaration checked for nested-name-specifier. 287/// \param IsExtension If not null and the declaration is accepted as an 288/// extension, the pointed variable is assigned true. 289bool Sema::isAcceptableNestedNameSpecifier(const NamedDecl *SD, 290 bool *IsExtension) { 291 if (!SD) 292 return false; 293 294 SD = SD->getUnderlyingDecl(); 295 296 // Namespace and namespace aliases are fine. 297 if (isa<NamespaceDecl>(SD)) 298 return true; 299 300 if (!isa<TypeDecl>(SD)) 301 return false; 302 303 // Determine whether we have a class (or, in C++11, an enum) or 304 // a typedef thereof. If so, build the nested-name-specifier. 305 QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD)); 306 if (T->isDependentType()) 307 return true; 308 if (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) { 309 if (TD->getUnderlyingType()->isRecordType()) 310 return true; 311 if (TD->getUnderlyingType()->isEnumeralType()) { 312 if (Context.getLangOpts().CPlusPlus11) 313 return true; 314 if (IsExtension) 315 *IsExtension = true; 316 } 317 } else if (isa<RecordDecl>(SD)) { 318 return true; 319 } else if (isa<EnumDecl>(SD)) { 320 if (Context.getLangOpts().CPlusPlus11) 321 return true; 322 if (IsExtension) 323 *IsExtension = true; 324 } 325 326 return false; 327} 328 329/// \brief If the given nested-name-specifier begins with a bare identifier 330/// (e.g., Base::), perform name lookup for that identifier as a 331/// nested-name-specifier within the given scope, and return the result of that 332/// name lookup. 333NamedDecl *Sema::FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS) { 334 if (!S || !NNS) 335 return nullptr; 336 337 while (NNS->getPrefix()) 338 NNS = NNS->getPrefix(); 339 340 if (NNS->getKind() != NestedNameSpecifier::Identifier) 341 return nullptr; 342 343 LookupResult Found(*this, NNS->getAsIdentifier(), SourceLocation(), 344 LookupNestedNameSpecifierName); 345 LookupName(Found, S); 346 assert(!Found.isAmbiguous() && "Cannot handle ambiguities here yet"); 347 348 if (!Found.isSingleResult()) 349 return nullptr; 350 351 NamedDecl *Result = Found.getFoundDecl(); 352 if (isAcceptableNestedNameSpecifier(Result)) 353 return Result; 354 355 return nullptr; 356} 357 358bool Sema::isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS, 359 SourceLocation IdLoc, 360 IdentifierInfo &II, 361 ParsedType ObjectTypePtr) { 362 QualType ObjectType = GetTypeFromParser(ObjectTypePtr); 363 LookupResult Found(*this, &II, IdLoc, LookupNestedNameSpecifierName); 364 365 // Determine where to perform name lookup 366 DeclContext *LookupCtx = nullptr; 367 bool isDependent = false; 368 if (!ObjectType.isNull()) { 369 // This nested-name-specifier occurs in a member access expression, e.g., 370 // x->B::f, and we are looking into the type of the object. 371 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist"); 372 LookupCtx = computeDeclContext(ObjectType); 373 isDependent = ObjectType->isDependentType(); 374 } else if (SS.isSet()) { 375 // This nested-name-specifier occurs after another nested-name-specifier, 376 // so long into the context associated with the prior nested-name-specifier. 377 LookupCtx = computeDeclContext(SS, false); 378 isDependent = isDependentScopeSpecifier(SS); 379 Found.setContextRange(SS.getRange()); 380 } 381 382 if (LookupCtx) { 383 // Perform "qualified" name lookup into the declaration context we 384 // computed, which is either the type of the base of a member access 385 // expression or the declaration context associated with a prior 386 // nested-name-specifier. 387 388 // The declaration context must be complete. 389 if (!LookupCtx->isDependentContext() && 390 RequireCompleteDeclContext(SS, LookupCtx)) 391 return false; 392 393 LookupQualifiedName(Found, LookupCtx); 394 } else if (isDependent) { 395 return false; 396 } else { 397 LookupName(Found, S); 398 } 399 Found.suppressDiagnostics(); 400 401 return Found.getAsSingle<NamespaceDecl>(); 402} 403 404namespace { 405 406// Callback to only accept typo corrections that can be a valid C++ member 407// intializer: either a non-static field member or a base class. 408class NestedNameSpecifierValidatorCCC : public CorrectionCandidateCallback { 409 public: 410 explicit NestedNameSpecifierValidatorCCC(Sema &SRef) 411 : SRef(SRef) {} 412 413 bool ValidateCandidate(const TypoCorrection &candidate) override { 414 return SRef.isAcceptableNestedNameSpecifier(candidate.getCorrectionDecl()); 415 } 416 417 private: 418 Sema &SRef; 419}; 420 421} 422 423/// \brief Build a new nested-name-specifier for "identifier::", as described 424/// by ActOnCXXNestedNameSpecifier. 425/// 426/// \param S Scope in which the nested-name-specifier occurs. 427/// \param Identifier Identifier in the sequence "identifier" "::". 428/// \param IdentifierLoc Location of the \p Identifier. 429/// \param CCLoc Location of "::" following Identifier. 430/// \param ObjectType Type of postfix expression if the nested-name-specifier 431/// occurs in construct like: <tt>ptr->nns::f</tt>. 432/// \param EnteringContext If true, enter the context specified by the 433/// nested-name-specifier. 434/// \param SS Optional nested name specifier preceding the identifier. 435/// \param ScopeLookupResult Provides the result of name lookup within the 436/// scope of the nested-name-specifier that was computed at template 437/// definition time. 438/// \param ErrorRecoveryLookup Specifies if the method is called to improve 439/// error recovery and what kind of recovery is performed. 440/// \param IsCorrectedToColon If not null, suggestion of replace '::' -> ':' 441/// are allowed. The bool value pointed by this parameter is set to 442/// 'true' if the identifier is treated as if it was followed by ':', 443/// not '::'. 444/// 445/// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in 446/// that it contains an extra parameter \p ScopeLookupResult, which provides 447/// the result of name lookup within the scope of the nested-name-specifier 448/// that was computed at template definition time. 449/// 450/// If ErrorRecoveryLookup is true, then this call is used to improve error 451/// recovery. This means that it should not emit diagnostics, it should 452/// just return true on failure. It also means it should only return a valid 453/// scope if it *knows* that the result is correct. It should not return in a 454/// dependent context, for example. Nor will it extend \p SS with the scope 455/// specifier. 456bool Sema::BuildCXXNestedNameSpecifier(Scope *S, 457 IdentifierInfo &Identifier, 458 SourceLocation IdentifierLoc, 459 SourceLocation CCLoc, 460 QualType ObjectType, 461 bool EnteringContext, 462 CXXScopeSpec &SS, 463 NamedDecl *ScopeLookupResult, 464 bool ErrorRecoveryLookup, 465 bool *IsCorrectedToColon) { 466 LookupResult Found(*this, &Identifier, IdentifierLoc, 467 LookupNestedNameSpecifierName); 468 469 // Determine where to perform name lookup 470 DeclContext *LookupCtx = nullptr; 471 bool isDependent = false; 472 if (IsCorrectedToColon) 473 *IsCorrectedToColon = false; 474 if (!ObjectType.isNull()) { 475 // This nested-name-specifier occurs in a member access expression, e.g., 476 // x->B::f, and we are looking into the type of the object. 477 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist"); 478 LookupCtx = computeDeclContext(ObjectType); 479 isDependent = ObjectType->isDependentType(); 480 } else if (SS.isSet()) { 481 // This nested-name-specifier occurs after another nested-name-specifier, 482 // so look into the context associated with the prior nested-name-specifier. 483 LookupCtx = computeDeclContext(SS, EnteringContext); 484 isDependent = isDependentScopeSpecifier(SS); 485 Found.setContextRange(SS.getRange()); 486 } 487 488 bool ObjectTypeSearchedInScope = false; 489 if (LookupCtx) { 490 // Perform "qualified" name lookup into the declaration context we 491 // computed, which is either the type of the base of a member access 492 // expression or the declaration context associated with a prior 493 // nested-name-specifier. 494 495 // The declaration context must be complete. 496 if (!LookupCtx->isDependentContext() && 497 RequireCompleteDeclContext(SS, LookupCtx)) 498 return true; 499 500 LookupQualifiedName(Found, LookupCtx); 501 502 if (!ObjectType.isNull() && Found.empty()) { 503 // C++ [basic.lookup.classref]p4: 504 // If the id-expression in a class member access is a qualified-id of 505 // the form 506 // 507 // class-name-or-namespace-name::... 508 // 509 // the class-name-or-namespace-name following the . or -> operator is 510 // looked up both in the context of the entire postfix-expression and in 511 // the scope of the class of the object expression. If the name is found 512 // only in the scope of the class of the object expression, the name 513 // shall refer to a class-name. If the name is found only in the 514 // context of the entire postfix-expression, the name shall refer to a 515 // class-name or namespace-name. [...] 516 // 517 // Qualified name lookup into a class will not find a namespace-name, 518 // so we do not need to diagnose that case specifically. However, 519 // this qualified name lookup may find nothing. In that case, perform 520 // unqualified name lookup in the given scope (if available) or 521 // reconstruct the result from when name lookup was performed at template 522 // definition time. 523 if (S) 524 LookupName(Found, S); 525 else if (ScopeLookupResult) 526 Found.addDecl(ScopeLookupResult); 527 528 ObjectTypeSearchedInScope = true; 529 } 530 } else if (!isDependent) { 531 // Perform unqualified name lookup in the current scope. 532 LookupName(Found, S); 533 } 534 535 if (Found.isAmbiguous()) 536 return true; 537 538 // If we performed lookup into a dependent context and did not find anything, 539 // that's fine: just build a dependent nested-name-specifier. 540 if (Found.empty() && isDependent && 541 !(LookupCtx && LookupCtx->isRecord() && 542 (!cast<CXXRecordDecl>(LookupCtx)->hasDefinition() || 543 !cast<CXXRecordDecl>(LookupCtx)->hasAnyDependentBases()))) { 544 // Don't speculate if we're just trying to improve error recovery. 545 if (ErrorRecoveryLookup) 546 return true; 547 548 // We were not able to compute the declaration context for a dependent 549 // base object type or prior nested-name-specifier, so this 550 // nested-name-specifier refers to an unknown specialization. Just build 551 // a dependent nested-name-specifier. 552 SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc); 553 return false; 554 } 555 556 if (Found.empty() && !ErrorRecoveryLookup) { 557 // If identifier is not found as class-name-or-namespace-name, but is found 558 // as other entity, don't look for typos. 559 LookupResult R(*this, Found.getLookupNameInfo(), LookupOrdinaryName); 560 if (LookupCtx) 561 LookupQualifiedName(R, LookupCtx); 562 else if (S && !isDependent) 563 LookupName(R, S); 564 if (!R.empty()) { 565 // Don't diagnose problems with this speculative lookup. 566 R.suppressDiagnostics(); 567 // The identifier is found in ordinary lookup. If correction to colon is 568 // allowed, suggest replacement to ':'. 569 if (IsCorrectedToColon) { 570 *IsCorrectedToColon = true; 571 Diag(CCLoc, diag::err_nested_name_spec_is_not_class) 572 << &Identifier << getLangOpts().CPlusPlus 573 << FixItHint::CreateReplacement(CCLoc, ":"); 574 if (NamedDecl *ND = R.getAsSingle<NamedDecl>()) 575 Diag(ND->getLocation(), diag::note_declared_at); 576 return true; 577 } 578 // Replacement '::' -> ':' is not allowed, just issue respective error. 579 Diag(R.getNameLoc(), diag::err_expected_class_or_namespace) 580 << &Identifier << getLangOpts().CPlusPlus; 581 if (NamedDecl *ND = R.getAsSingle<NamedDecl>()) 582 Diag(ND->getLocation(), diag::note_entity_declared_at) << &Identifier; 583 return true; 584 } 585 } 586 587 if (Found.empty() && !ErrorRecoveryLookup && !getLangOpts().MSVCCompat) { 588 // We haven't found anything, and we're not recovering from a 589 // different kind of error, so look for typos. 590 DeclarationName Name = Found.getLookupName(); 591 Found.clear(); 592 if (TypoCorrection Corrected = CorrectTypo( 593 Found.getLookupNameInfo(), Found.getLookupKind(), S, &SS, 594 llvm::make_unique<NestedNameSpecifierValidatorCCC>(*this), 595 CTK_ErrorRecovery, LookupCtx, EnteringContext)) { 596 if (LookupCtx) { 597 bool DroppedSpecifier = 598 Corrected.WillReplaceSpecifier() && 599 Name.getAsString() == Corrected.getAsString(getLangOpts()); 600 if (DroppedSpecifier) 601 SS.clear(); 602 diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest) 603 << Name << LookupCtx << DroppedSpecifier 604 << SS.getRange()); 605 } else 606 diagnoseTypo(Corrected, PDiag(diag::err_undeclared_var_use_suggest) 607 << Name); 608 609 if (NamedDecl *ND = Corrected.getFoundDecl()) 610 Found.addDecl(ND); 611 Found.setLookupName(Corrected.getCorrection()); 612 } else { 613 Found.setLookupName(&Identifier); 614 } 615 } 616 617 NamedDecl *SD = 618 Found.isSingleResult() ? Found.getRepresentativeDecl() : nullptr; 619 bool IsExtension = false; 620 bool AcceptSpec = isAcceptableNestedNameSpecifier(SD, &IsExtension); 621 if (!AcceptSpec && IsExtension) { 622 AcceptSpec = true; 623 Diag(IdentifierLoc, diag::ext_nested_name_spec_is_enum); 624 } 625 if (AcceptSpec) { 626 if (!ObjectType.isNull() && !ObjectTypeSearchedInScope && 627 !getLangOpts().CPlusPlus11) { 628 // C++03 [basic.lookup.classref]p4: 629 // [...] If the name is found in both contexts, the 630 // class-name-or-namespace-name shall refer to the same entity. 631 // 632 // We already found the name in the scope of the object. Now, look 633 // into the current scope (the scope of the postfix-expression) to 634 // see if we can find the same name there. As above, if there is no 635 // scope, reconstruct the result from the template instantiation itself. 636 // 637 // Note that C++11 does *not* perform this redundant lookup. 638 NamedDecl *OuterDecl; 639 if (S) { 640 LookupResult FoundOuter(*this, &Identifier, IdentifierLoc, 641 LookupNestedNameSpecifierName); 642 LookupName(FoundOuter, S); 643 OuterDecl = FoundOuter.getAsSingle<NamedDecl>(); 644 } else 645 OuterDecl = ScopeLookupResult; 646 647 if (isAcceptableNestedNameSpecifier(OuterDecl) && 648 OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() && 649 (!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) || 650 !Context.hasSameType( 651 Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)), 652 Context.getTypeDeclType(cast<TypeDecl>(SD))))) { 653 if (ErrorRecoveryLookup) 654 return true; 655 656 Diag(IdentifierLoc, 657 diag::err_nested_name_member_ref_lookup_ambiguous) 658 << &Identifier; 659 Diag(SD->getLocation(), diag::note_ambig_member_ref_object_type) 660 << ObjectType; 661 Diag(OuterDecl->getLocation(), diag::note_ambig_member_ref_scope); 662 663 // Fall through so that we'll pick the name we found in the object 664 // type, since that's probably what the user wanted anyway. 665 } 666 } 667 668 if (auto *TD = dyn_cast_or_null<TypedefNameDecl>(SD)) 669 MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false); 670 671 // If we're just performing this lookup for error-recovery purposes, 672 // don't extend the nested-name-specifier. Just return now. 673 if (ErrorRecoveryLookup) 674 return false; 675 676 // The use of a nested name specifier may trigger deprecation warnings. 677 DiagnoseUseOfDecl(SD, CCLoc); 678 679 680 if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD)) { 681 SS.Extend(Context, Namespace, IdentifierLoc, CCLoc); 682 return false; 683 } 684 685 if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD)) { 686 SS.Extend(Context, Alias, IdentifierLoc, CCLoc); 687 return false; 688 } 689 690 QualType T = 691 Context.getTypeDeclType(cast<TypeDecl>(SD->getUnderlyingDecl())); 692 TypeLocBuilder TLB; 693 if (isa<InjectedClassNameType>(T)) { 694 InjectedClassNameTypeLoc InjectedTL 695 = TLB.push<InjectedClassNameTypeLoc>(T); 696 InjectedTL.setNameLoc(IdentifierLoc); 697 } else if (isa<RecordType>(T)) { 698 RecordTypeLoc RecordTL = TLB.push<RecordTypeLoc>(T); 699 RecordTL.setNameLoc(IdentifierLoc); 700 } else if (isa<TypedefType>(T)) { 701 TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(T); 702 TypedefTL.setNameLoc(IdentifierLoc); 703 } else if (isa<EnumType>(T)) { 704 EnumTypeLoc EnumTL = TLB.push<EnumTypeLoc>(T); 705 EnumTL.setNameLoc(IdentifierLoc); 706 } else if (isa<TemplateTypeParmType>(T)) { 707 TemplateTypeParmTypeLoc TemplateTypeTL 708 = TLB.push<TemplateTypeParmTypeLoc>(T); 709 TemplateTypeTL.setNameLoc(IdentifierLoc); 710 } else if (isa<UnresolvedUsingType>(T)) { 711 UnresolvedUsingTypeLoc UnresolvedTL 712 = TLB.push<UnresolvedUsingTypeLoc>(T); 713 UnresolvedTL.setNameLoc(IdentifierLoc); 714 } else if (isa<SubstTemplateTypeParmType>(T)) { 715 SubstTemplateTypeParmTypeLoc TL 716 = TLB.push<SubstTemplateTypeParmTypeLoc>(T); 717 TL.setNameLoc(IdentifierLoc); 718 } else if (isa<SubstTemplateTypeParmPackType>(T)) { 719 SubstTemplateTypeParmPackTypeLoc TL 720 = TLB.push<SubstTemplateTypeParmPackTypeLoc>(T); 721 TL.setNameLoc(IdentifierLoc); 722 } else { 723 llvm_unreachable("Unhandled TypeDecl node in nested-name-specifier"); 724 } 725 726 if (T->isEnumeralType()) 727 Diag(IdentifierLoc, diag::warn_cxx98_compat_enum_nested_name_spec); 728 729 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T), 730 CCLoc); 731 return false; 732 } 733 734 // Otherwise, we have an error case. If we don't want diagnostics, just 735 // return an error now. 736 if (ErrorRecoveryLookup) 737 return true; 738 739 // If we didn't find anything during our lookup, try again with 740 // ordinary name lookup, which can help us produce better error 741 // messages. 742 if (Found.empty()) { 743 Found.clear(LookupOrdinaryName); 744 LookupName(Found, S); 745 } 746 747 // In Microsoft mode, if we are within a templated function and we can't 748 // resolve Identifier, then extend the SS with Identifier. This will have 749 // the effect of resolving Identifier during template instantiation. 750 // The goal is to be able to resolve a function call whose 751 // nested-name-specifier is located inside a dependent base class. 752 // Example: 753 // 754 // class C { 755 // public: 756 // static void foo2() { } 757 // }; 758 // template <class T> class A { public: typedef C D; }; 759 // 760 // template <class T> class B : public A<T> { 761 // public: 762 // void foo() { D::foo2(); } 763 // }; 764 if (getLangOpts().MSVCCompat) { 765 DeclContext *DC = LookupCtx ? LookupCtx : CurContext; 766 if (DC->isDependentContext() && DC->isFunctionOrMethod()) { 767 CXXRecordDecl *ContainingClass = dyn_cast<CXXRecordDecl>(DC->getParent()); 768 if (ContainingClass && ContainingClass->hasAnyDependentBases()) { 769 Diag(IdentifierLoc, diag::ext_undeclared_unqual_id_with_dependent_base) 770 << &Identifier << ContainingClass; 771 SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc); 772 return false; 773 } 774 } 775 } 776 777 if (!Found.empty()) { 778 if (TypeDecl *TD = Found.getAsSingle<TypeDecl>()) 779 Diag(IdentifierLoc, diag::err_expected_class_or_namespace) 780 << QualType(TD->getTypeForDecl(), 0) << getLangOpts().CPlusPlus; 781 else { 782 Diag(IdentifierLoc, diag::err_expected_class_or_namespace) 783 << &Identifier << getLangOpts().CPlusPlus; 784 if (NamedDecl *ND = Found.getAsSingle<NamedDecl>()) 785 Diag(ND->getLocation(), diag::note_entity_declared_at) << &Identifier; 786 } 787 } else if (SS.isSet()) 788 Diag(IdentifierLoc, diag::err_no_member) << &Identifier << LookupCtx 789 << SS.getRange(); 790 else 791 Diag(IdentifierLoc, diag::err_undeclared_var_use) << &Identifier; 792 793 return true; 794} 795 796bool Sema::ActOnCXXNestedNameSpecifier(Scope *S, 797 IdentifierInfo &Identifier, 798 SourceLocation IdentifierLoc, 799 SourceLocation CCLoc, 800 ParsedType ObjectType, 801 bool EnteringContext, 802 CXXScopeSpec &SS, 803 bool ErrorRecoveryLookup, 804 bool *IsCorrectedToColon) { 805 if (SS.isInvalid()) 806 return true; 807 808 return BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, CCLoc, 809 GetTypeFromParser(ObjectType), 810 EnteringContext, SS, 811 /*ScopeLookupResult=*/nullptr, false, 812 IsCorrectedToColon); 813} 814 815bool Sema::ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS, 816 const DeclSpec &DS, 817 SourceLocation ColonColonLoc) { 818 if (SS.isInvalid() || DS.getTypeSpecType() == DeclSpec::TST_error) 819 return true; 820 821 assert(DS.getTypeSpecType() == DeclSpec::TST_decltype); 822 823 QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc()); 824 if (!T->isDependentType() && !T->getAs<TagType>()) { 825 Diag(DS.getTypeSpecTypeLoc(), diag::err_expected_class_or_namespace) 826 << T << getLangOpts().CPlusPlus; 827 return true; 828 } 829 830 TypeLocBuilder TLB; 831 DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T); 832 DecltypeTL.setNameLoc(DS.getTypeSpecTypeLoc()); 833 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T), 834 ColonColonLoc); 835 return false; 836} 837 838/// IsInvalidUnlessNestedName - This method is used for error recovery 839/// purposes to determine whether the specified identifier is only valid as 840/// a nested name specifier, for example a namespace name. It is 841/// conservatively correct to always return false from this method. 842/// 843/// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier. 844bool Sema::IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS, 845 IdentifierInfo &Identifier, 846 SourceLocation IdentifierLoc, 847 SourceLocation ColonLoc, 848 ParsedType ObjectType, 849 bool EnteringContext) { 850 if (SS.isInvalid()) 851 return false; 852 853 return !BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, ColonLoc, 854 GetTypeFromParser(ObjectType), 855 EnteringContext, SS, 856 /*ScopeLookupResult=*/nullptr, true); 857} 858 859bool Sema::ActOnCXXNestedNameSpecifier(Scope *S, 860 CXXScopeSpec &SS, 861 SourceLocation TemplateKWLoc, 862 TemplateTy Template, 863 SourceLocation TemplateNameLoc, 864 SourceLocation LAngleLoc, 865 ASTTemplateArgsPtr TemplateArgsIn, 866 SourceLocation RAngleLoc, 867 SourceLocation CCLoc, 868 bool EnteringContext) { 869 if (SS.isInvalid()) 870 return true; 871 872 // Translate the parser's template argument list in our AST format. 873 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc); 874 translateTemplateArguments(TemplateArgsIn, TemplateArgs); 875 876 DependentTemplateName *DTN = Template.get().getAsDependentTemplateName(); 877 if (DTN && DTN->isIdentifier()) { 878 // Handle a dependent template specialization for which we cannot resolve 879 // the template name. 880 assert(DTN->getQualifier() == SS.getScopeRep()); 881 QualType T = Context.getDependentTemplateSpecializationType(ETK_None, 882 DTN->getQualifier(), 883 DTN->getIdentifier(), 884 TemplateArgs); 885 886 // Create source-location information for this type. 887 TypeLocBuilder Builder; 888 DependentTemplateSpecializationTypeLoc SpecTL 889 = Builder.push<DependentTemplateSpecializationTypeLoc>(T); 890 SpecTL.setElaboratedKeywordLoc(SourceLocation()); 891 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context)); 892 SpecTL.setTemplateKeywordLoc(TemplateKWLoc); 893 SpecTL.setTemplateNameLoc(TemplateNameLoc); 894 SpecTL.setLAngleLoc(LAngleLoc); 895 SpecTL.setRAngleLoc(RAngleLoc); 896 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 897 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo()); 898 899 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T), 900 CCLoc); 901 return false; 902 } 903 904 TemplateDecl *TD = Template.get().getAsTemplateDecl(); 905 if (Template.get().getAsOverloadedTemplate() || DTN || 906 isa<FunctionTemplateDecl>(TD) || isa<VarTemplateDecl>(TD)) { 907 SourceRange R(TemplateNameLoc, RAngleLoc); 908 if (SS.getRange().isValid()) 909 R.setBegin(SS.getRange().getBegin()); 910 911 Diag(CCLoc, diag::err_non_type_template_in_nested_name_specifier) 912 << (TD && isa<VarTemplateDecl>(TD)) << Template.get() << R; 913 NoteAllFoundTemplates(Template.get()); 914 return true; 915 } 916 917 // We were able to resolve the template name to an actual template. 918 // Build an appropriate nested-name-specifier. 919 QualType T = CheckTemplateIdType(Template.get(), TemplateNameLoc, 920 TemplateArgs); 921 if (T.isNull()) 922 return true; 923 924 // Alias template specializations can produce types which are not valid 925 // nested name specifiers. 926 if (!T->isDependentType() && !T->getAs<TagType>()) { 927 Diag(TemplateNameLoc, diag::err_nested_name_spec_non_tag) << T; 928 NoteAllFoundTemplates(Template.get()); 929 return true; 930 } 931 932 // Provide source-location information for the template specialization type. 933 TypeLocBuilder Builder; 934 TemplateSpecializationTypeLoc SpecTL 935 = Builder.push<TemplateSpecializationTypeLoc>(T); 936 SpecTL.setTemplateKeywordLoc(TemplateKWLoc); 937 SpecTL.setTemplateNameLoc(TemplateNameLoc); 938 SpecTL.setLAngleLoc(LAngleLoc); 939 SpecTL.setRAngleLoc(RAngleLoc); 940 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 941 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo()); 942 943 944 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T), 945 CCLoc); 946 return false; 947} 948 949namespace { 950 /// \brief A structure that stores a nested-name-specifier annotation, 951 /// including both the nested-name-specifier 952 struct NestedNameSpecifierAnnotation { 953 NestedNameSpecifier *NNS; 954 }; 955} 956 957void *Sema::SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS) { 958 if (SS.isEmpty() || SS.isInvalid()) 959 return nullptr; 960 961 void *Mem = Context.Allocate((sizeof(NestedNameSpecifierAnnotation) + 962 SS.location_size()), 963 llvm::alignOf<NestedNameSpecifierAnnotation>()); 964 NestedNameSpecifierAnnotation *Annotation 965 = new (Mem) NestedNameSpecifierAnnotation; 966 Annotation->NNS = SS.getScopeRep(); 967 memcpy(Annotation + 1, SS.location_data(), SS.location_size()); 968 return Annotation; 969} 970 971void Sema::RestoreNestedNameSpecifierAnnotation(void *AnnotationPtr, 972 SourceRange AnnotationRange, 973 CXXScopeSpec &SS) { 974 if (!AnnotationPtr) { 975 SS.SetInvalid(AnnotationRange); 976 return; 977 } 978 979 NestedNameSpecifierAnnotation *Annotation 980 = static_cast<NestedNameSpecifierAnnotation *>(AnnotationPtr); 981 SS.Adopt(NestedNameSpecifierLoc(Annotation->NNS, Annotation + 1)); 982} 983 984bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) { 985 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec."); 986 987 NestedNameSpecifier *Qualifier = SS.getScopeRep(); 988 989 // There are only two places a well-formed program may qualify a 990 // declarator: first, when defining a namespace or class member 991 // out-of-line, and second, when naming an explicitly-qualified 992 // friend function. The latter case is governed by 993 // C++03 [basic.lookup.unqual]p10: 994 // In a friend declaration naming a member function, a name used 995 // in the function declarator and not part of a template-argument 996 // in a template-id is first looked up in the scope of the member 997 // function's class. If it is not found, or if the name is part of 998 // a template-argument in a template-id, the look up is as 999 // described for unqualified names in the definition of the class 1000 // granting friendship. 1001 // i.e. we don't push a scope unless it's a class member. 1002 1003 switch (Qualifier->getKind()) { 1004 case NestedNameSpecifier::Global: 1005 case NestedNameSpecifier::Namespace: 1006 case NestedNameSpecifier::NamespaceAlias: 1007 // These are always namespace scopes. We never want to enter a 1008 // namespace scope from anything but a file context. 1009 return CurContext->getRedeclContext()->isFileContext(); 1010 1011 case NestedNameSpecifier::Identifier: 1012 case NestedNameSpecifier::TypeSpec: 1013 case NestedNameSpecifier::TypeSpecWithTemplate: 1014 case NestedNameSpecifier::Super: 1015 // These are never namespace scopes. 1016 return true; 1017 } 1018 1019 llvm_unreachable("Invalid NestedNameSpecifier::Kind!"); 1020} 1021 1022/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global 1023/// scope or nested-name-specifier) is parsed, part of a declarator-id. 1024/// After this method is called, according to [C++ 3.4.3p3], names should be 1025/// looked up in the declarator-id's scope, until the declarator is parsed and 1026/// ActOnCXXExitDeclaratorScope is called. 1027/// The 'SS' should be a non-empty valid CXXScopeSpec. 1028bool Sema::ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS) { 1029 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec."); 1030 1031 if (SS.isInvalid()) return true; 1032 1033 DeclContext *DC = computeDeclContext(SS, true); 1034 if (!DC) return true; 1035 1036 // Before we enter a declarator's context, we need to make sure that 1037 // it is a complete declaration context. 1038 if (!DC->isDependentContext() && RequireCompleteDeclContext(SS, DC)) 1039 return true; 1040 1041 EnterDeclaratorContext(S, DC); 1042 1043 // Rebuild the nested name specifier for the new scope. 1044 if (DC->isDependentContext()) 1045 RebuildNestedNameSpecifierInCurrentInstantiation(SS); 1046 1047 return false; 1048} 1049 1050/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously 1051/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same 1052/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well. 1053/// Used to indicate that names should revert to being looked up in the 1054/// defining scope. 1055void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) { 1056 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec."); 1057 if (SS.isInvalid()) 1058 return; 1059 assert(!SS.isInvalid() && computeDeclContext(SS, true) && 1060 "exiting declarator scope we never really entered"); 1061 ExitDeclaratorContext(S); 1062} 1063