C++ NamedDecl::getLocation方法代码示例

/// \brief Give notes for a set of overloads.
///
/// A companion to isExprCallable. In cases when the name that the programmer
/// wrote was an overloaded function, we may be able to make some guesses about
/// plausible overloads based on their return types; such guesses can be handed
/// off to this method to be emitted as notes.
///
/// \param Overloads - The overloads to note.
/// \param FinalNoteLoc - If we've suppressed printing some overloads due to
///  -fshow-overloads=best, this is the location to attach to the note about too
///  many candidates. Typically this will be the location of the original
///  ill-formed expression.
static void noteOverloads(Sema &S, const UnresolvedSetImpl &Overloads,
                          const SourceLocation FinalNoteLoc) {
  int ShownOverloads = 0;
  int SuppressedOverloads = 0;
  for (UnresolvedSetImpl::iterator It = Overloads.begin(),
       DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
    // FIXME: Magic number for max shown overloads stolen from
    // OverloadCandidateSet::NoteCandidates.
    if (ShownOverloads >= 4 && S.Diags.getShowOverloads() == Ovl_Best) {
      ++SuppressedOverloads;
      continue;
    }

    NamedDecl *Fn = (*It)->getUnderlyingDecl();
    S.Diag(Fn->getLocation(), diag::note_possible_target_of_call);
    ++ShownOverloads;
  }

  if (SuppressedOverloads)
    S.Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates)
      << SuppressedOverloads;
}

//.........这里部分代码省略.........
    
    // We were not able to compute the declaration context for a dependent
    // base object type or prior nested-name-specifier, so this
    // nested-name-specifier refers to an unknown specialization. Just build
    // a dependent nested-name-specifier.
    SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc);
    return false;
  } 
  
  // FIXME: Deal with ambiguities cleanly.

  if (Found.empty() && !ErrorRecoveryLookup) {
    // We haven't found anything, and we're not recovering from a
    // different kind of error, so look for typos.
    DeclarationName Name = Found.getLookupName();
    TypoCorrection Corrected;
    Found.clear();
    if ((Corrected = CorrectTypo(Found.getLookupNameInfo(),
                                 Found.getLookupKind(), S, &SS, LookupCtx,
                                 EnteringContext, CTC_NoKeywords)) &&
        isAcceptableNestedNameSpecifier(Corrected.getCorrectionDecl())) {
      std::string CorrectedStr(Corrected.getAsString(getLangOptions()));
      std::string CorrectedQuotedStr(Corrected.getQuoted(getLangOptions()));
      if (LookupCtx)
        Diag(Found.getNameLoc(), diag::err_no_member_suggest)
          << Name << LookupCtx << CorrectedQuotedStr << SS.getRange()
          << FixItHint::CreateReplacement(Found.getNameLoc(), CorrectedStr);
      else
        Diag(Found.getNameLoc(), diag::err_undeclared_var_use_suggest)
          << Name << CorrectedQuotedStr
          << FixItHint::CreateReplacement(Found.getNameLoc(), CorrectedStr);
      
      if (NamedDecl *ND = Corrected.getCorrectionDecl()) {
        Diag(ND->getLocation(), diag::note_previous_decl) << CorrectedQuotedStr;
        Found.addDecl(ND);
      }
      Found.setLookupName(Corrected.getCorrection());
    } else {
      Found.setLookupName(&Identifier);
    }
  }

  NamedDecl *SD = Found.getAsSingle<NamedDecl>();
  if (isAcceptableNestedNameSpecifier(SD)) {
    if (!ObjectType.isNull() && !ObjectTypeSearchedInScope) {
      // C++ [basic.lookup.classref]p4:
      //   [...] If the name is found in both contexts, the
      //   class-name-or-namespace-name shall refer to the same entity.
      //
      // We already found the name in the scope of the object. Now, look
      // into the current scope (the scope of the postfix-expression) to
      // see if we can find the same name there. As above, if there is no
      // scope, reconstruct the result from the template instantiation itself.
      NamedDecl *OuterDecl;
      if (S) {
        LookupResult FoundOuter(*this, &Identifier, IdentifierLoc, 
                                LookupNestedNameSpecifierName);
        LookupName(FoundOuter, S);
        OuterDecl = FoundOuter.getAsSingle<NamedDecl>();
      } else
        OuterDecl = ScopeLookupResult;

      if (isAcceptableNestedNameSpecifier(OuterDecl) &&
          OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() &&
          (!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) ||
           !Context.hasSameType(

//.........这里部分代码省略.........
        (!cast<CXXRecordDecl>(LookupCtx)->hasDefinition() ||
         !cast<CXXRecordDecl>(LookupCtx)->hasAnyDependentBases()))) {
    // Don't speculate if we're just trying to improve error recovery.
    if (ErrorRecoveryLookup)
      return true;

    // We were not able to compute the declaration context for a dependent
    // base object type or prior nested-name-specifier, so this
    // nested-name-specifier refers to an unknown specialization. Just build
    // a dependent nested-name-specifier.
    SS.Extend(Context, IdInfo.Identifier, IdInfo.IdentifierLoc, IdInfo.CCLoc);
    return false;
  }

  if (Found.empty() && !ErrorRecoveryLookup) {
    // If identifier is not found as class-name-or-namespace-name, but is found
    // as other entity, don't look for typos.
    LookupResult R(*this, Found.getLookupNameInfo(), LookupOrdinaryName);
    if (LookupCtx)
      LookupQualifiedName(R, LookupCtx);
    else if (S && !isDependent)
      LookupName(R, S);
    if (!R.empty()) {
      // Don't diagnose problems with this speculative lookup.
      R.suppressDiagnostics();
      // The identifier is found in ordinary lookup. If correction to colon is
      // allowed, suggest replacement to ':'.
      if (IsCorrectedToColon) {
        *IsCorrectedToColon = true;
        Diag(IdInfo.CCLoc, diag::err_nested_name_spec_is_not_class)
            << IdInfo.Identifier << getLangOpts().CPlusPlus
            << FixItHint::CreateReplacement(IdInfo.CCLoc, ":");
        if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
          Diag(ND->getLocation(), diag::note_declared_at);
        return true;
      }
      // Replacement '::' -> ':' is not allowed, just issue respective error.
      Diag(R.getNameLoc(), OnlyNamespace
                               ? unsigned(diag::err_expected_namespace_name)
                               : unsigned(diag::err_expected_class_or_namespace))
          << IdInfo.Identifier << getLangOpts().CPlusPlus;
      if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
        Diag(ND->getLocation(), diag::note_entity_declared_at)
            << IdInfo.Identifier;
      return true;
    }
  }

  if (Found.empty() && !ErrorRecoveryLookup && !getLangOpts().MSVCCompat) {
    // We haven't found anything, and we're not recovering from a
    // different kind of error, so look for typos.
    DeclarationName Name = Found.getLookupName();
    Found.clear();
    NestedNameSpecifierValidatorCCC CCC(*this);
    if (TypoCorrection Corrected = CorrectTypo(
            Found.getLookupNameInfo(), Found.getLookupKind(), S, &SS, CCC,
            CTK_ErrorRecovery, LookupCtx, EnteringContext)) {
      if (LookupCtx) {
        bool DroppedSpecifier =
            Corrected.WillReplaceSpecifier() &&
            Name.getAsString() == Corrected.getAsString(getLangOpts());
        if (DroppedSpecifier)
          SS.clear();
        diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest)
                                  << Name << LookupCtx << DroppedSpecifier
                                  << SS.getRange());

  bool DeclExtractor::CheckTagDeclaration(TagDecl* NewTD,
                                          LookupResult& Previous){
    // If the decl is already known invalid, don't check it.
    if (NewTD->isInvalidDecl())
      return false;

    IdentifierInfo* Name = NewTD->getIdentifier();
    // If this is not a definition, it must have a name.
    assert((Name != 0 || NewTD->isThisDeclarationADefinition()) &&
           "Nameless record must be a definition!");

    // Figure out the underlying type if this a enum declaration. We need to do
    // this early, because it's needed to detect if this is an incompatible
    // redeclaration.

    TagDecl::TagKind Kind = NewTD->getTagKind();
    bool Invalid = false;
    assert(NewTD->getNumTemplateParameterLists() == 0
           && "Cannot handle that yet!");
    bool isExplicitSpecialization = false;

    if (Kind == TTK_Enum) {
      EnumDecl* ED = cast<EnumDecl>(NewTD);
      bool ScopedEnum = ED->isScoped();
      const QualType QT = ED->getIntegerType();

      if (QT.isNull() && ScopedEnum)
        // No underlying type explicitly specified, or we failed to parse the
        // type, default to int.
        ; //EnumUnderlying = m_Context->IntTy.getTypePtr();
      else if (!QT.isNull()) {
        // C++0x 7.2p2: The type-specifier-seq of an enum-base shall name an
        // integral type; any cv-qualification is ignored.

        SourceLocation UnderlyingLoc;
        TypeSourceInfo* TI = 0;
        if ((TI = ED->getIntegerTypeSourceInfo()))
          UnderlyingLoc = TI->getTypeLoc().getBeginLoc();

        if (!QT->isDependentType() && !QT->isIntegralType(*m_Context)) {
          m_Sema->Diag(UnderlyingLoc, diag::err_enum_invalid_underlying)
            << QT;
        }
        if (TI)
          m_Sema->DiagnoseUnexpandedParameterPack(UnderlyingLoc, TI,
                                                Sema::UPPC_FixedUnderlyingType);
      }
    }

    DeclContext *SearchDC = m_Sema->CurContext;
    DeclContext *DC = m_Sema->CurContext;
    //bool isStdBadAlloc = false;
    SourceLocation NameLoc = NewTD->getLocation();
    // if (Name && SS.isNotEmpty()) {
    //   // We have a nested-name tag ('struct foo::bar').

    //   // Check for invalid 'foo::'.
    //   if (SS.isInvalid()) {
    //     Name = 0;
    //     goto CreateNewDecl;
    //   }

    //   // If this is a friend or a reference to a class in a dependent
    //   // context, don't try to make a decl for it.
    //   if (TUK == TUK_Friend || TUK == TUK_Reference) {
    //     DC = computeDeclContext(SS, false);
    //     if (!DC) {
    //       IsDependent = true;
    //       return 0;
    //     }
    //   } else {
    //     DC = computeDeclContext(SS, true);
    //     if (!DC) {
    //       Diag(SS.getRange().getBegin(),
    //            diag::err_dependent_nested_name_spec)
    //         << SS.getRange();
    //       return 0;
    //     }
    //   }

    //   if (RequireCompleteDeclContext(SS, DC))
    //     return 0;

    //   SearchDC = DC;
    //   // Look-up name inside 'foo::'.
    //   LookupQualifiedName(Previous, DC);

    //   if (Previous.isAmbiguous())
    //     return 0;

    //   if (Previous.empty()) {
    //     // Name lookup did not find anything. However, if the
    //     // nested-name-specifier refers to the current instantiation,
    //     // and that current instantiation has any dependent base
    //     // classes, we might find something at instantiation time: treat
    //     // this as a dependent elaborated-type-specifier.
    //     // But this only makes any sense for reference-like lookups.
    //     if (Previous.wasNotFoundInCurrentInstantiation() &&
    //         (TUK == TUK_Reference || TUK == TUK_Friend)) {
    //       IsDependent = true;
//.........这里部分代码省略.........

/// Look up the std::coroutine_traits<...>::promise_type for the given
/// function type.
static QualType lookupPromiseType(Sema &S, const FunctionProtoType *FnType,
                                  SourceLocation KwLoc,
                                  SourceLocation FuncLoc) {
  // FIXME: Cache std::coroutine_traits once we've found it.
  NamespaceDecl *StdExp = S.lookupStdExperimentalNamespace();
  if (!StdExp) {
    S.Diag(KwLoc, diag::err_implied_coroutine_type_not_found)
        << "std::experimental::coroutine_traits";
    return QualType();
  }

  LookupResult Result(S, &S.PP.getIdentifierTable().get("coroutine_traits"),
                      FuncLoc, Sema::LookupOrdinaryName);
  if (!S.LookupQualifiedName(Result, StdExp)) {
    S.Diag(KwLoc, diag::err_implied_coroutine_type_not_found)
        << "std::experimental::coroutine_traits";
    return QualType();
  }

  ClassTemplateDecl *CoroTraits = Result.getAsSingle<ClassTemplateDecl>();
  if (!CoroTraits) {
    Result.suppressDiagnostics();
    // We found something weird. Complain about the first thing we found.
    NamedDecl *Found = *Result.begin();
    S.Diag(Found->getLocation(), diag::err_malformed_std_coroutine_traits);
    return QualType();
  }

  // Form template argument list for coroutine_traits<R, P1, P2, ...>.
  TemplateArgumentListInfo Args(KwLoc, KwLoc);
  Args.addArgument(TemplateArgumentLoc(
      TemplateArgument(FnType->getReturnType()),
      S.Context.getTrivialTypeSourceInfo(FnType->getReturnType(), KwLoc)));
  // FIXME: If the function is a non-static member function, add the type
  // of the implicit object parameter before the formal parameters.
  for (QualType T : FnType->getParamTypes())
    Args.addArgument(TemplateArgumentLoc(
        TemplateArgument(T), S.Context.getTrivialTypeSourceInfo(T, KwLoc)));

  // Build the template-id.
  QualType CoroTrait =
      S.CheckTemplateIdType(TemplateName(CoroTraits), KwLoc, Args);
  if (CoroTrait.isNull())
    return QualType();
  if (S.RequireCompleteType(KwLoc, CoroTrait,
                            diag::err_coroutine_type_missing_specialization))
    return QualType();

  auto *RD = CoroTrait->getAsCXXRecordDecl();
  assert(RD && "specialization of class template is not a class?");

  // Look up the ::promise_type member.
  LookupResult R(S, &S.PP.getIdentifierTable().get("promise_type"), KwLoc,
                 Sema::LookupOrdinaryName);
  S.LookupQualifiedName(R, RD);
  auto *Promise = R.getAsSingle<TypeDecl>();
  if (!Promise) {
    S.Diag(FuncLoc,
           diag::err_implied_std_coroutine_traits_promise_type_not_found)
        << RD;
    return QualType();
  }
  // The promise type is required to be a class type.
  QualType PromiseType = S.Context.getTypeDeclType(Promise);

  auto buildElaboratedType = [&]() {
    auto *NNS = NestedNameSpecifier::Create(S.Context, nullptr, StdExp);
    NNS = NestedNameSpecifier::Create(S.Context, NNS, false,
                                      CoroTrait.getTypePtr());
    return S.Context.getElaboratedType(ETK_None, NNS, PromiseType);
  };

  if (!PromiseType->getAsCXXRecordDecl()) {
    S.Diag(FuncLoc,
           diag::err_implied_std_coroutine_traits_promise_type_not_class)
        << buildElaboratedType();
    return QualType();
  }
  if (S.RequireCompleteType(FuncLoc, buildElaboratedType(),
                            diag::err_coroutine_promise_type_incomplete))
    return QualType();

  return PromiseType;
}

Sema::ObjCMessageKind Sema::getObjCMessageKind(Scope *S,
                                               IdentifierInfo *Name,
                                               SourceLocation NameLoc,
                                               bool IsSuper,
                                               bool HasTrailingDot,
                                               ParsedType &ReceiverType) {
  ReceiverType = ParsedType();

  // If the identifier is "super" and there is no trailing dot, we're
  // messaging super. If the identifier is "super" and there is a
  // trailing dot, it's an instance message.
  if (IsSuper && S->isInObjcMethodScope())
    return HasTrailingDot? ObjCInstanceMessage : ObjCSuperMessage;
  
  LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
  LookupName(Result, S);
  
  switch (Result.getResultKind()) {
  case LookupResult::NotFound:
    // Normal name lookup didn't find anything. If we're in an
    // Objective-C method, look for ivars. If we find one, we're done!
    // FIXME: This is a hack. Ivar lookup should be part of normal
    // lookup.
    if (ObjCMethodDecl *Method = getCurMethodDecl()) {
      ObjCInterfaceDecl *ClassDeclared;
      if (Method->getClassInterface()->lookupInstanceVariable(Name, 
                                                              ClassDeclared))
        return ObjCInstanceMessage;
    }
  
    // Break out; we'll perform typo correction below.
    break;

  case LookupResult::NotFoundInCurrentInstantiation:
  case LookupResult::FoundOverloaded:
  case LookupResult::FoundUnresolvedValue:
  case LookupResult::Ambiguous:
    Result.suppressDiagnostics();
    return ObjCInstanceMessage;

  case LookupResult::Found: {
    // If the identifier is a class or not, and there is a trailing dot,
    // it's an instance message.
    if (HasTrailingDot)
      return ObjCInstanceMessage;
    // We found something. If it's a type, then we have a class
    // message. Otherwise, it's an instance message.
    NamedDecl *ND = Result.getFoundDecl();
    QualType T;
    if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(ND))
      T = Context.getObjCInterfaceType(Class);
    else if (TypeDecl *Type = dyn_cast<TypeDecl>(ND))
      T = Context.getTypeDeclType(Type);
    else 
      return ObjCInstanceMessage;

    //  We have a class message, and T is the type we're
    //  messaging. Build source-location information for it.
    TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
    ReceiverType = CreateParsedType(T, TSInfo);
    return ObjCClassMessage;
  }
  }

  // Determine our typo-correction context.
  CorrectTypoContext CTC = CTC_Expression;
  if (ObjCMethodDecl *Method = getCurMethodDecl())
    if (Method->getClassInterface() &&
        Method->getClassInterface()->getSuperClass())
      CTC = CTC_ObjCMessageReceiver;
      
  if (DeclarationName Corrected = CorrectTypo(Result, S, 0, 0, false, CTC)) {
    if (Result.isSingleResult()) {
      // If we found a declaration, correct when it refers to an Objective-C
      // class.
      NamedDecl *ND = Result.getFoundDecl();
      if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(ND)) {
        Diag(NameLoc, diag::err_unknown_receiver_suggest)
          << Name << Result.getLookupName()
          << FixItHint::CreateReplacement(SourceRange(NameLoc),
                                          ND->getNameAsString());
        Diag(ND->getLocation(), diag::note_previous_decl)
          << Corrected;

        QualType T = Context.getObjCInterfaceType(Class);
        TypeSourceInfo *TSInfo = Context.getTrivialTypeSourceInfo(T, NameLoc);
        ReceiverType = CreateParsedType(T, TSInfo);
        return ObjCClassMessage;
      }
    } else if (Result.empty() && Corrected.getAsIdentifierInfo() &&
               Corrected.getAsIdentifierInfo()->isStr("super")) {
      // If we've found the keyword "super", this is a send to super.
      Diag(NameLoc, diag::err_unknown_receiver_suggest)
        << Name << Corrected
        << FixItHint::CreateReplacement(SourceRange(NameLoc), "super");
      return ObjCSuperMessage;
    }
  }
  
  // Fall back: let the parser try to parse it as an instance message.
//.........这里部分代码省略.........

/// Diagnose the path which caused the given declaration or base class
/// to become inaccessible.
static void DiagnoseAccessPath(Sema &S,
                               const EffectiveContext &EC,
                               AccessTarget &Entity) {
  AccessSpecifier Access = Entity.getAccess();
  const CXXRecordDecl *NamingClass = Entity.getNamingClass();
  NamingClass = NamingClass->getCanonicalDecl();

  NamedDecl *D = (Entity.isMemberAccess() ? Entity.getTargetDecl() : 0);
  const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();

  // Easy case: the decl's natural access determined its path access.
  // We have to check against AS_private here in case Access is AS_none,
  // indicating a non-public member of a private base class.
  if (D && (Access == D->getAccess() || D->getAccess() == AS_private)) {
    switch (HasAccess(S, EC, DeclaringClass, D->getAccess(), Entity)) {
    case AR_inaccessible: {
      S.Diag(D->getLocation(), diag::note_access_natural)
        << (unsigned) (Access == AS_protected)
        << /*FIXME: not implicitly*/ 0;
      return;
    }

    case AR_accessible: break;

    case AR_dependent:
      llvm_unreachable("can't diagnose dependent access failures");
      return;
    }
  }

  CXXBasePaths Paths;
  CXXBasePath &Path = *FindBestPath(S, EC, Entity, AS_public, Paths);

  CXXBasePath::iterator I = Path.end(), E = Path.begin();
  while (I != E) {
    --I;

    const CXXBaseSpecifier *BS = I->Base;
    AccessSpecifier BaseAccess = BS->getAccessSpecifier();

    // If this is public inheritance, or the derived class is a friend,
    // skip this step.
    if (BaseAccess == AS_public)
      continue;

    switch (GetFriendKind(S, EC, I->Class)) {
    case AR_accessible: continue;
    case AR_inaccessible: break;
    case AR_dependent:
      llvm_unreachable("can't diagnose dependent access failures");
    }

    // Check whether this base specifier is the tighest point
    // constraining access.  We have to check against AS_private for
    // the same reasons as above.
    if (BaseAccess == AS_private || BaseAccess >= Access) {

      // We're constrained by inheritance, but we want to say
      // "declared private here" if we're diagnosing a hierarchy
      // conversion and this is the final step.
      unsigned diagnostic;
      if (D) diagnostic = diag::note_access_constrained_by_path;
      else if (I + 1 == Path.end()) diagnostic = diag::note_access_natural;
      else diagnostic = diag::note_access_constrained_by_path;

      S.Diag(BS->getSourceRange().getBegin(), diagnostic)
        << BS->getSourceRange()
        << (BaseAccess == AS_protected)
        << (BS->getAccessSpecifierAsWritten() == AS_none);
      return;
    }
  }

  llvm_unreachable("access not apparently constrained by path");
}

NamespaceDecl *Sema::ActOnRogerNamespaceHeaderPart(DeclContext *DeclContext, IdentifierInfo *II,
        SourceLocation IdentLoc,
        AttributeList *AttrList) {
    // set CurContext

    SourceLocation NamespaceLoc;
    SourceLocation InlineLoc;
    SourceLocation StartLoc = InlineLoc.isValid() ? InlineLoc : NamespaceLoc;

    assert(II);
    SourceLocation Loc = IdentLoc;
    bool IsInline = false;
    bool IsInvalid = false;
    bool IsStd = false;
    bool AddToKnown = false;
    //Scope *DeclRegionScope = NamespcScope->getParent();

    NamespaceDecl *PrevNS = 0;
    // C++ [namespace.def]p2:
    //   The identifier in an original-namespace-definition shall not
    //   have been previously defined in the declarative region in
    //   which the original-namespace-definition appears. The
    //   identifier in an original-namespace-definition is the name of
    //   the namespace. Subsequently in that declarative region, it is
    //   treated as an original-namespace-name.
    //
    // Since namespace names are unique in their scope, and we don't
    // look through using directives, just look for any ordinary names.

    const unsigned IDNS = Decl::IDNS_Ordinary | Decl::IDNS_Member |
                          Decl::IDNS_Type | Decl::IDNS_Using | Decl::IDNS_Tag |
                          Decl::IDNS_Namespace;
    NamedDecl *PrevDecl = 0;
    DeclContext::lookup_result R = DeclContext->getRedeclContext()->lookup(II);
    for (DeclContext::lookup_iterator I = R.begin(), E = R.end(); I != E;
            ++I) {
        if ((*I)->getIdentifierNamespace() & IDNS) {
            PrevDecl = *I;
            break;
        }
    }

    PrevNS = dyn_cast_or_null<NamespaceDecl>(PrevDecl);

    if (PrevNS) {
        // This is an extended namespace definition.
        if (IsInline != PrevNS->isInline()) {
//      DiagnoseNamespaceInlineMismatch(*this, NamespaceLoc, Loc, II,
//                                      &IsInline, PrevNS);
            assert(false && "need to implement this");
        }
        return PrevNS;
    } else if (PrevDecl) {
        // This is an invalid name redefinition.
        Diag(Loc, diag::err_redefinition_different_kind)
                << II;
        Diag(PrevDecl->getLocation(), diag::note_previous_definition);
        IsInvalid = true;
        // Continue on to push Namespc as current DeclContext and return it.
    } else if (II->isStr("std") &&
               DeclContext->getRedeclContext()->isTranslationUnit()) {
        // This is the first "real" definition of the namespace "std", so update
        // our cache of the "std" namespace to point at this definition.
        PrevNS = getStdNamespace();
        IsStd = true;
        AddToKnown = !IsInline;
    } else {
        // We've seen this namespace for the first time.
        AddToKnown = !IsInline;
    }

    NamespaceDecl *Namespc = NamespaceDecl::Create(Context, DeclContext, IsInline,
                             StartLoc, Loc, II, PrevNS);
    Namespc->IsRogerNamespace = true;

    if (IsInvalid)
        Namespc->setInvalidDecl();

    //ProcessDeclAttributeList(DeclRegionScope, Namespc, AttrList);

    // FIXME: Should we be merging attributes?
    if (const VisibilityAttr *Attr = Namespc->getAttr<VisibilityAttr>())
        PushNamespaceVisibilityAttr(Attr, Loc);

    if (IsStd)
        StdNamespace = Namespc;
    if (AddToKnown)
        KnownNamespaces[Namespc] = false;

    DeclContext->addDecl(Namespc);

    if (PrevNS) {
        return PrevNS;
    } else {
        return Namespc;
    }
}

//.........这里部分代码省略.........
    // base object type or prior nested-name-specifier, so this
    // nested-name-specifier refers to an unknown specialization. Just build
    // a dependent nested-name-specifier.
    if (!Prefix)
      return NestedNameSpecifier::Create(Context, &II);

    return NestedNameSpecifier::Create(Context, Prefix, &II);
  } else {
    // Perform unqualified name lookup in the current scope.
    LookupName(Found, S);
  }

  // FIXME: Deal with ambiguities cleanly.

  if (Found.empty() && !ErrorRecoveryLookup) {
    // We haven't found anything, and we're not recovering from a
    // different kind of error, so look for typos.
    DeclarationName Name = Found.getLookupName();
    if (CorrectTypo(Found, S, &SS, LookupCtx, EnteringContext) &&
        Found.isSingleResult() &&
        isAcceptableNestedNameSpecifier(Found.getAsSingle<NamedDecl>())) {
      if (LookupCtx)
        Diag(Found.getNameLoc(), diag::err_no_member_suggest)
          << Name << LookupCtx << Found.getLookupName() << SS.getRange()
          << CodeModificationHint::CreateReplacement(Found.getNameLoc(),
                                           Found.getLookupName().getAsString());
      else
        Diag(Found.getNameLoc(), diag::err_undeclared_var_use_suggest)
          << Name << Found.getLookupName()
          << CodeModificationHint::CreateReplacement(Found.getNameLoc(),
                                           Found.getLookupName().getAsString());
      
      if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
        Diag(ND->getLocation(), diag::note_previous_decl)
          << ND->getDeclName();
    } else
      Found.clear();
  }

  NamedDecl *SD = Found.getAsSingle<NamedDecl>();
  if (isAcceptableNestedNameSpecifier(SD)) {
    if (!ObjectType.isNull() && !ObjectTypeSearchedInScope) {
      // C++ [basic.lookup.classref]p4:
      //   [...] If the name is found in both contexts, the
      //   class-name-or-namespace-name shall refer to the same entity.
      //
      // We already found the name in the scope of the object. Now, look
      // into the current scope (the scope of the postfix-expression) to
      // see if we can find the same name there. As above, if there is no
      // scope, reconstruct the result from the template instantiation itself.
      NamedDecl *OuterDecl;
      if (S) {
        LookupResult FoundOuter(*this, &II, IdLoc, LookupNestedNameSpecifierName);
        LookupName(FoundOuter, S);
        OuterDecl = FoundOuter.getAsSingle<NamedDecl>();
      } else
        OuterDecl = ScopeLookupResult;

      if (isAcceptableNestedNameSpecifier(OuterDecl) &&
          OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() &&
          (!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) ||
           !Context.hasSameType(
                            Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)),
                               Context.getTypeDeclType(cast<TypeDecl>(SD))))) {
             if (ErrorRecoveryLookup)
               return 0;

//.........这里部分代码省略.........
  if (R.empty()) {
    // FIXME: make sure this prints the '*' for pointer-to-struct types (?)
    //DeclContext *DC = BaseType->getAs<StructType>()->getDecl();
    // FIXME: clang prints DC instead of BaseExprType here. Don't do that,
    // else we don't print struct names right. However, make sure ParenTypes
    // get desugared once they exist.
    Diag(R.getNameLoc(), diag::no_field) << II << BaseExprType;
    //Diag(R.getNameLoc(), diag::err_no_member)
      //<< MemberName << DC
      //<< (BaseExpr ? BaseExpr->getSourceRange() : SourceRange());
    return ExprError();
  }

  assert(R.isSingleResult());
  NamedDecl *MemberDecl = R.getFoundDecl();
#if 0
  DeclAccessPair FoundDecl = R.begin().getPair();

  // If the decl being referenced had an error, return an error for this
  // sub-expr without emitting another error, in order to avoid cascading
  // error cases.
  if (MemberDecl->isInvalidDecl())
    return ExprError();

  bool ShouldCheckUse = true;
  if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MemberDecl)) {
    // Don't diagnose the use of a virtual member function unless it's
    // explicitly qualified.
    if (MD->isVirtual())
      ShouldCheckUse = false;
  }

  // Check the use of this member.
  if (ShouldCheckUse && DiagnoseUseOfDecl(MemberDecl, MemberLoc)) {
    Owned(BaseExpr);
    return ExprError();
  }
#endif

  if (FieldDecl *FD = dyn_cast<FieldDecl>(MemberDecl)) {
    //return BuildFieldReferenceExpr(*this, BaseExpr, IsArrow,
                                   //FD, FoundDecl, MemberNameInfo);
    return Owned(BuildMemberExpr(*this, Context, BaseExpr, FD,
                                 R.getNameLoc(), FD->getType()));
  }

#if 0
  if (IndirectFieldDecl *FD = dyn_cast<IndirectFieldDecl>(MemberDecl))
    // We may have found a field within an anonymous union or struct
    // (C++ [class.union]).
    return BuildAnonymousStructUnionMemberReference(MemberLoc, FD,
                                                    BaseExpr, OpLoc);

  if (VarDecl *Var = dyn_cast<VarDecl>(MemberDecl)) {
    return Owned(BuildMemberExpr(*this, Context, BaseExpr, IsArrow,
                                 Var, FoundDecl, MemberNameInfo,
                                 Var->getType().getNonReferenceType(),
                                 VK_LValue, OK_Ordinary));
  }

  if (CXXMethodDecl *MemberFn = dyn_cast<CXXMethodDecl>(MemberDecl)) {
    ExprValueKind valueKind;
    QualType type;
    if (MemberFn->isInstance()) {
      valueKind = VK_RValue;
      type = Context.BoundMemberTy;
    } else {
      valueKind = VK_LValue;
      type = MemberFn->getType();
    }

    return Owned(BuildMemberExpr(*this, Context, BaseExpr, IsArrow,
                                 MemberFn, FoundDecl, 
                                 MemberNameInfo, type, valueKind,
                                 OK_Ordinary));
  }
  assert(!isa<FunctionDecl>(MemberDecl) && "member function not C++ method?");

  if (EnumConstantDecl *Enum = dyn_cast<EnumConstantDecl>(MemberDecl)) {
    return Owned(BuildMemberExpr(*this, Context, BaseExpr, IsArrow,
                                 Enum, FoundDecl, MemberNameInfo,
                                 Enum->getType(), VK_RValue, OK_Ordinary));
  }

  Owned(BaseExpr);

  // We found something that we didn't expect. Complain.
  if (isa<TypeDecl>(MemberDecl))
    Diag(MemberLoc, diag::err_typecheck_member_reference_type)
      << MemberName << BaseType << int(IsArrow);
  else
    Diag(MemberLoc, diag::err_typecheck_member_reference_unknown)
      << MemberName << BaseType << int(IsArrow);

  Diag(MemberDecl->getLocation(), diag::note_member_declared_here)
    << MemberName;
  R.suppressDiagnostics();
#endif
  return ExprError();
}