Merge branch 'master' of ssh://bitbucket.org/czan/honours

1 files changed, 958 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaCXXScopeSpec.cpp b/clang/lib/Sema/SemaCXXScopeSpec.cpp
new file mode 100644
index 0000000..5a0fcec
--- /dev/null
+++ b/clang/lib/Sema/SemaCXXScopeSpec.cpp
@@ -0,0 +1,958 @@
+//===--- SemaCXXScopeSpec.cpp - Semantic Analysis for C++ scope specifiers-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements C++ semantic analysis for scope specifiers.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Sema/SemaInternal.h"
+#include "clang/Sema/Lookup.h"
+#include "clang/Sema/Template.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/NestedNameSpecifier.h"
+#include "clang/Basic/PartialDiagnostic.h"
+#include "clang/Sema/DeclSpec.h"
+#include "TypeLocBuilder.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace clang;
+
+/// \brief Find the current instantiation that associated with the given type.
+static CXXRecordDecl *getCurrentInstantiationOf(QualType T, 
+                                                DeclContext *CurContext) {
+  if (T.isNull())
+    return 0;
+
+  const Type *Ty = T->getCanonicalTypeInternal().getTypePtr();
+  if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
+    CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl());
+    if (!T->isDependentType())
+      return Record;
+
+    // This may be a member of a class template or class template partial
+    // specialization. If it's part of the current semantic context, then it's
+    // an injected-class-name;
+    for (; !CurContext->isFileContext(); CurContext = CurContext->getParent())
+      if (CurContext->Equals(Record))
+        return Record;
+    
+    return 0;
+  } else if (isa<InjectedClassNameType>(Ty))
+    return cast<InjectedClassNameType>(Ty)->getDecl();
+  else
+    return 0;
+}
+
+/// \brief Compute the DeclContext that is associated with the given type.
+///
+/// \param T the type for which we are attempting to find a DeclContext.
+///
+/// \returns the declaration context represented by the type T,
+/// or NULL if the declaration context cannot be computed (e.g., because it is
+/// dependent and not the current instantiation).
+DeclContext *Sema::computeDeclContext(QualType T) {
+  if (!T->isDependentType())
+    if (const TagType *Tag = T->getAs<TagType>())
+      return Tag->getDecl();
+
+  return ::getCurrentInstantiationOf(T, CurContext);
+}
+
+/// \brief Compute the DeclContext that is associated with the given
+/// scope specifier.
+///
+/// \param SS the C++ scope specifier as it appears in the source
+///
+/// \param EnteringContext when true, we will be entering the context of
+/// this scope specifier, so we can retrieve the declaration context of a
+/// class template or class template partial specialization even if it is
+/// not the current instantiation.
+///
+/// \returns the declaration context represented by the scope specifier @p SS,
+/// or NULL if the declaration context cannot be computed (e.g., because it is
+/// dependent and not the current instantiation).
+DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
+                                      bool EnteringContext) {
+  if (!SS.isSet() || SS.isInvalid())
+    return 0;
+
+  NestedNameSpecifier *NNS
+    = static_cast<NestedNameSpecifier *>(SS.getScopeRep());
+  if (NNS->isDependent()) {
+    // If this nested-name-specifier refers to the current
+    // instantiation, return its DeclContext.
+    if (CXXRecordDecl *Record = getCurrentInstantiationOf(NNS))
+      return Record;
+
+    if (EnteringContext) {
+      const Type *NNSType = NNS->getAsType();
+      if (!NNSType) {
+        return 0;
+      }
+
+      // Look through type alias templates, per C++0x [temp.dep.type]p1.
+      NNSType = Context.getCanonicalType(NNSType);
+      if (const TemplateSpecializationType *SpecType
+            = NNSType->getAs<TemplateSpecializationType>()) {
+        // We are entering the context of the nested name specifier, so try to
+        // match the nested name specifier to either a primary class template
+        // or a class template partial specialization.
+        if (ClassTemplateDecl *ClassTemplate
+              = dyn_cast_or_null<ClassTemplateDecl>(
+                            SpecType->getTemplateName().getAsTemplateDecl())) {
+          QualType ContextType
+            = Context.getCanonicalType(QualType(SpecType, 0));
+
+          // If the type of the nested name specifier is the same as the
+          // injected class name of the named class template, we're entering
+          // into that class template definition.
+          QualType Injected
+            = ClassTemplate->getInjectedClassNameSpecialization();
+          if (Context.hasSameType(Injected, ContextType))
+            return ClassTemplate->getTemplatedDecl();
+
+          // If the type of the nested name specifier is the same as the
+          // type of one of the class template's class template partial
+          // specializations, we're entering into the definition of that
+          // class template partial specialization.
+          if (ClassTemplatePartialSpecializationDecl *PartialSpec
+                = ClassTemplate->findPartialSpecialization(ContextType))
+            return PartialSpec;
+        }
+      } else if (const RecordType *RecordT = NNSType->getAs<RecordType>()) {
+        // The nested name specifier refers to a member of a class template.
+        return RecordT->getDecl();
+      }
+    }
+
+    return 0;
+  }
+
+  switch (NNS->getKind()) {
+  case NestedNameSpecifier::Identifier:
+    llvm_unreachable("Dependent nested-name-specifier has no DeclContext");
+
+  case NestedNameSpecifier::Namespace:
+    return NNS->getAsNamespace();
+
+  case NestedNameSpecifier::NamespaceAlias:
+    return NNS->getAsNamespaceAlias()->getNamespace();
+
+  case NestedNameSpecifier::TypeSpec:
+  case NestedNameSpecifier::TypeSpecWithTemplate: {
+    const TagType *Tag = NNS->getAsType()->getAs<TagType>();
+    assert(Tag && "Non-tag type in nested-name-specifier");
+    return Tag->getDecl();
+  }
+
+  case NestedNameSpecifier::Global:
+    return Context.getTranslationUnitDecl();
+  }
+
+  llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
+}
+
+bool Sema::isDependentScopeSpecifier(const CXXScopeSpec &SS) {
+  if (!SS.isSet() || SS.isInvalid())
+    return false;
+
+  NestedNameSpecifier *NNS
+    = static_cast<NestedNameSpecifier *>(SS.getScopeRep());
+  return NNS->isDependent();
+}
+
+// \brief Determine whether this C++ scope specifier refers to an
+// unknown specialization, i.e., a dependent type that is not the
+// current instantiation.
+bool Sema::isUnknownSpecialization(const CXXScopeSpec &SS) {
+  if (!isDependentScopeSpecifier(SS))
+    return false;
+
+  NestedNameSpecifier *NNS
+    = static_cast<NestedNameSpecifier *>(SS.getScopeRep());
+  return getCurrentInstantiationOf(NNS) == 0;
+}
+
+/// \brief If the given nested name specifier refers to the current
+/// instantiation, return the declaration that corresponds to that
+/// current instantiation (C++0x [temp.dep.type]p1).
+///
+/// \param NNS a dependent nested name specifier.
+CXXRecordDecl *Sema::getCurrentInstantiationOf(NestedNameSpecifier *NNS) {
+  assert(getLangOpts().CPlusPlus && "Only callable in C++");
+  assert(NNS->isDependent() && "Only dependent nested-name-specifier allowed");
+
+  if (!NNS->getAsType())
+    return 0;
+
+  QualType T = QualType(NNS->getAsType(), 0);
+  return ::getCurrentInstantiationOf(T, CurContext);
+}
+
+/// \brief Require that the context specified by SS be complete.
+///
+/// If SS refers to a type, this routine checks whether the type is
+/// complete enough (or can be made complete enough) for name lookup
+/// into the DeclContext. A type that is not yet completed can be
+/// considered "complete enough" if it is a class/struct/union/enum
+/// that is currently being defined. Or, if we have a type that names
+/// a class template specialization that is not a complete type, we
+/// will attempt to instantiate that class template.
+bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
+                                      DeclContext *DC) {
+  assert(DC != 0 && "given null context");
+
+  TagDecl *tag = dyn_cast<TagDecl>(DC);
+
+  // If this is a dependent type, then we consider it complete.
+  if (!tag || tag->isDependentContext())
+    return false;
+
+  // If we're currently defining this type, then lookup into the
+  // type is okay: don't complain that it isn't complete yet.
+  QualType type = Context.getTypeDeclType(tag);
+  const TagType *tagType = type->getAs<TagType>();
+  if (tagType && tagType->isBeingDefined())
+    return false;
+
+  SourceLocation loc = SS.getLastQualifierNameLoc();
+  if (loc.isInvalid()) loc = SS.getRange().getBegin();
+
+  // The type must be complete.
+  if (RequireCompleteType(loc, type,
+                          PDiag(diag::err_incomplete_nested_name_spec)
+                            << SS.getRange())) {
+    SS.SetInvalid(SS.getRange());
+    return true;
+  }
+
+  // Fixed enum types are complete, but they aren't valid as scopes
+  // until we see a definition, so awkwardly pull out this special
+  // case.
+  const EnumType *enumType = dyn_cast_or_null<EnumType>(tagType);
+  if (!enumType || enumType->getDecl()->isCompleteDefinition())
+    return false;
+
+  // Try to instantiate the definition, if this is a specialization of an
+  // enumeration temploid.
+  EnumDecl *ED = enumType->getDecl();
+  if (EnumDecl *Pattern = ED->getInstantiatedFromMemberEnum()) {
+    MemberSpecializationInfo *MSI = ED->getMemberSpecializationInfo();
+    if (MSI->getTemplateSpecializationKind() != TSK_ExplicitSpecialization) {
+      if (InstantiateEnum(loc, ED, Pattern, getTemplateInstantiationArgs(ED),
+                          TSK_ImplicitInstantiation)) {
+        SS.SetInvalid(SS.getRange());
+        return true;
+      }
+      return false;
+    }
+  }
+
+  Diag(loc, diag::err_incomplete_nested_name_spec)
+    << type << SS.getRange();
+  SS.SetInvalid(SS.getRange());
+  return true;
+}
+
+bool Sema::ActOnCXXGlobalScopeSpecifier(Scope *S, SourceLocation CCLoc,
+                                        CXXScopeSpec &SS) {
+  SS.MakeGlobal(Context, CCLoc);
+  return false;
+}
+
+/// \brief Determines whether the given declaration is an valid acceptable
+/// result for name lookup of a nested-name-specifier.
+bool Sema::isAcceptableNestedNameSpecifier(NamedDecl *SD) {
+  if (!SD)
+    return false;
+
+  // Namespace and namespace aliases are fine.
+  if (isa<NamespaceDecl>(SD) || isa<NamespaceAliasDecl>(SD))
+    return true;
+
+  if (!isa<TypeDecl>(SD))
+    return false;
+
+  // Determine whether we have a class (or, in C++11, an enum) or
+  // a typedef thereof. If so, build the nested-name-specifier.
+  QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
+  if (T->isDependentType())
+    return true;
+  else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) {
+    if (TD->getUnderlyingType()->isRecordType() ||
+        (Context.getLangOpts().CPlusPlus0x &&
+         TD->getUnderlyingType()->isEnumeralType()))
+      return true;
+  } else if (isa<RecordDecl>(SD) ||
+             (Context.getLangOpts().CPlusPlus0x && isa<EnumDecl>(SD)))
+    return true;
+
+  return false;
+}
+
+/// \brief If the given nested-name-specifier begins with a bare identifier
+/// (e.g., Base::), perform name lookup for that identifier as a
+/// nested-name-specifier within the given scope, and return the result of that
+/// name lookup.
+NamedDecl *Sema::FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS) {
+  if (!S || !NNS)
+    return 0;
+
+  while (NNS->getPrefix())
+    NNS = NNS->getPrefix();
+
+  if (NNS->getKind() != NestedNameSpecifier::Identifier)
+    return 0;
+
+  LookupResult Found(*this, NNS->getAsIdentifier(), SourceLocation(),
+                     LookupNestedNameSpecifierName);
+  LookupName(Found, S);
+  assert(!Found.isAmbiguous() && "Cannot handle ambiguities here yet");
+
+  if (!Found.isSingleResult())
+    return 0;
+
+  NamedDecl *Result = Found.getFoundDecl();
+  if (isAcceptableNestedNameSpecifier(Result))
+    return Result;
+
+  return 0;
+}
+
+bool Sema::isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
+                                        SourceLocation IdLoc,
+                                        IdentifierInfo &II,
+                                        ParsedType ObjectTypePtr) {
+  QualType ObjectType = GetTypeFromParser(ObjectTypePtr);
+  LookupResult Found(*this, &II, IdLoc, LookupNestedNameSpecifierName);
+  
+  // Determine where to perform name lookup
+  DeclContext *LookupCtx = 0;
+  bool isDependent = false;
+  if (!ObjectType.isNull()) {
+    // This nested-name-specifier occurs in a member access expression, e.g.,
+    // x->B::f, and we are looking into the type of the object.
+    assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
+    LookupCtx = computeDeclContext(ObjectType);
+    isDependent = ObjectType->isDependentType();
+  } else if (SS.isSet()) {
+    // This nested-name-specifier occurs after another nested-name-specifier,
+    // so long into the context associated with the prior nested-name-specifier.
+    LookupCtx = computeDeclContext(SS, false);
+    isDependent = isDependentScopeSpecifier(SS);
+    Found.setContextRange(SS.getRange());
+  }
+  
+  if (LookupCtx) {
+    // Perform "qualified" name lookup into the declaration context we
+    // computed, which is either the type of the base of a member access
+    // expression or the declaration context associated with a prior
+    // nested-name-specifier.
+    
+    // The declaration context must be complete.
+    if (!LookupCtx->isDependentContext() &&
+        RequireCompleteDeclContext(SS, LookupCtx))
+      return false;
+    
+    LookupQualifiedName(Found, LookupCtx);
+  } else if (isDependent) {
+    return false;
+  } else {
+    LookupName(Found, S);
+  }
+  Found.suppressDiagnostics();
+  
+  if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
+    return isa<NamespaceDecl>(ND) || isa<NamespaceAliasDecl>(ND);
+  
+  return false;
+}
+
+namespace {
+
+// Callback to only accept typo corrections that can be a valid C++ member
+// intializer: either a non-static field member or a base class.
+class NestedNameSpecifierValidatorCCC : public CorrectionCandidateCallback {
+ public:
+  explicit NestedNameSpecifierValidatorCCC(Sema &SRef)
+      : SRef(SRef) {}
+
+  virtual bool ValidateCandidate(const TypoCorrection &candidate) {
+    return SRef.isAcceptableNestedNameSpecifier(candidate.getCorrectionDecl());
+  }
+
+ private:
+  Sema &SRef;
+};
+
+}
+
+/// \brief Build a new nested-name-specifier for "identifier::", as described
+/// by ActOnCXXNestedNameSpecifier.
+///
+/// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
+/// that it contains an extra parameter \p ScopeLookupResult, which provides
+/// the result of name lookup within the scope of the nested-name-specifier
+/// that was computed at template definition time.
+///
+/// If ErrorRecoveryLookup is true, then this call is used to improve error
+/// recovery.  This means that it should not emit diagnostics, it should
+/// just return true on failure.  It also means it should only return a valid
+/// scope if it *knows* that the result is correct.  It should not return in a
+/// dependent context, for example. Nor will it extend \p SS with the scope
+/// specifier.
+bool Sema::BuildCXXNestedNameSpecifier(Scope *S,
+                                       IdentifierInfo &Identifier,
+                                       SourceLocation IdentifierLoc,
+                                       SourceLocation CCLoc,
+                                       QualType ObjectType,
+                                       bool EnteringContext,
+                                       CXXScopeSpec &SS,
+                                       NamedDecl *ScopeLookupResult,
+                                       bool ErrorRecoveryLookup) {
+  LookupResult Found(*this, &Identifier, IdentifierLoc, 
+                     LookupNestedNameSpecifierName);
+
+  // Determine where to perform name lookup
+  DeclContext *LookupCtx = 0;
+  bool isDependent = false;
+  if (!ObjectType.isNull()) {
+    // This nested-name-specifier occurs in a member access expression, e.g.,
+    // x->B::f, and we are looking into the type of the object.
+    assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
+    LookupCtx = computeDeclContext(ObjectType);
+    isDependent = ObjectType->isDependentType();
+  } else if (SS.isSet()) {
+    // This nested-name-specifier occurs after another nested-name-specifier,
+    // so look into the context associated with the prior nested-name-specifier.
+    LookupCtx = computeDeclContext(SS, EnteringContext);
+    isDependent = isDependentScopeSpecifier(SS);
+    Found.setContextRange(SS.getRange());
+  }
+
+
+  bool ObjectTypeSearchedInScope = false;
+  if (LookupCtx) {
+    // Perform "qualified" name lookup into the declaration context we
+    // computed, which is either the type of the base of a member access
+    // expression or the declaration context associated with a prior
+    // nested-name-specifier.
+
+    // The declaration context must be complete.
+    if (!LookupCtx->isDependentContext() &&
+        RequireCompleteDeclContext(SS, LookupCtx))
+      return true;
+
+    LookupQualifiedName(Found, LookupCtx);
+
+    if (!ObjectType.isNull() && Found.empty()) {
+      // C++ [basic.lookup.classref]p4:
+      //   If the id-expression in a class member access is a qualified-id of
+      //   the form
+      //
+      //        class-name-or-namespace-name::...
+      //
+      //   the class-name-or-namespace-name following the . or -> operator is
+      //   looked up both in the context of the entire postfix-expression and in
+      //   the scope of the class of the object expression. If the name is found
+      //   only in the scope of the class of the object expression, the name
+      //   shall refer to a class-name. If the name is found only in the
+      //   context of the entire postfix-expression, the name shall refer to a
+      //   class-name or namespace-name. [...]
+      //
+      // Qualified name lookup into a class will not find a namespace-name,
+      // so we do not need to diagnose that case specifically. However,
+      // this qualified name lookup may find nothing. In that case, perform
+      // unqualified name lookup in the given scope (if available) or
+      // reconstruct the result from when name lookup was performed at template
+      // definition time.
+      if (S)
+        LookupName(Found, S);
+      else if (ScopeLookupResult)
+        Found.addDecl(ScopeLookupResult);
+
+      ObjectTypeSearchedInScope = true;
+    }
+  } else if (!isDependent) {
+    // Perform unqualified name lookup in the current scope.
+    LookupName(Found, S);
+  }
+
+  // If we performed lookup into a dependent context and did not find anything,
+  // that's fine: just build a dependent nested-name-specifier.
+  if (Found.empty() && isDependent &&
+      !(LookupCtx && LookupCtx->isRecord() &&
+        (!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, &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();
+    NestedNameSpecifierValidatorCCC Validator(*this);
+    TypoCorrection Corrected;
+    Found.clear();
+    if ((Corrected = CorrectTypo(Found.getLookupNameInfo(),
+                                 Found.getLookupKind(), S, &SS, Validator,
+                                 LookupCtx, EnteringContext))) {
+      std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
+      std::string CorrectedQuotedStr(Corrected.getQuoted(getLangOpts()));
+      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(
+                            Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)),
+                               Context.getTypeDeclType(cast<TypeDecl>(SD))))) {
+         if (ErrorRecoveryLookup)
+           return true;
+
+         Diag(IdentifierLoc, 
+              diag::err_nested_name_member_ref_lookup_ambiguous)
+           << &Identifier;
+         Diag(SD->getLocation(), diag::note_ambig_member_ref_object_type)
+           << ObjectType;
+         Diag(OuterDecl->getLocation(), diag::note_ambig_member_ref_scope);
+
+         // Fall through so that we'll pick the name we found in the object
+         // type, since that's probably what the user wanted anyway.
+       }
+    }
+
+    // If we're just performing this lookup for error-recovery purposes, 
+    // don't extend the nested-name-specifier. Just return now.
+    if (ErrorRecoveryLookup)
+      return false;
+    
+    if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD)) {
+      SS.Extend(Context, Namespace, IdentifierLoc, CCLoc);
+      return false;
+    }
+
+    if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD)) {
+      SS.Extend(Context, Alias, IdentifierLoc, CCLoc);
+      return false;
+    }
+
+    QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
+    TypeLocBuilder TLB;
+    if (isa<InjectedClassNameType>(T)) {
+      InjectedClassNameTypeLoc InjectedTL
+        = TLB.push<InjectedClassNameTypeLoc>(T);
+      InjectedTL.setNameLoc(IdentifierLoc);
+    } else if (isa<RecordType>(T)) {
+      RecordTypeLoc RecordTL = TLB.push<RecordTypeLoc>(T);
+      RecordTL.setNameLoc(IdentifierLoc);
+    } else if (isa<TypedefType>(T)) {
+      TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(T);
+      TypedefTL.setNameLoc(IdentifierLoc);
+    } else if (isa<EnumType>(T)) {
+      EnumTypeLoc EnumTL = TLB.push<EnumTypeLoc>(T);
+      EnumTL.setNameLoc(IdentifierLoc);
+    } else if (isa<TemplateTypeParmType>(T)) {
+      TemplateTypeParmTypeLoc TemplateTypeTL
+        = TLB.push<TemplateTypeParmTypeLoc>(T);
+      TemplateTypeTL.setNameLoc(IdentifierLoc);
+    } else if (isa<UnresolvedUsingType>(T)) {
+      UnresolvedUsingTypeLoc UnresolvedTL
+        = TLB.push<UnresolvedUsingTypeLoc>(T);
+      UnresolvedTL.setNameLoc(IdentifierLoc);
+    } else if (isa<SubstTemplateTypeParmType>(T)) {
+      SubstTemplateTypeParmTypeLoc TL 
+        = TLB.push<SubstTemplateTypeParmTypeLoc>(T);
+      TL.setNameLoc(IdentifierLoc);
+    } else if (isa<SubstTemplateTypeParmPackType>(T)) {
+      SubstTemplateTypeParmPackTypeLoc TL
+        = TLB.push<SubstTemplateTypeParmPackTypeLoc>(T);
+      TL.setNameLoc(IdentifierLoc);
+    } else {
+      llvm_unreachable("Unhandled TypeDecl node in nested-name-specifier");
+    }
+
+    if (T->isEnumeralType())
+      Diag(IdentifierLoc, diag::warn_cxx98_compat_enum_nested_name_spec);
+
+    SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
+              CCLoc);
+    return false;
+  }
+
+  // Otherwise, we have an error case.  If we don't want diagnostics, just
+  // return an error now.
+  if (ErrorRecoveryLookup)
+    return true;
+
+  // If we didn't find anything during our lookup, try again with
+  // ordinary name lookup, which can help us produce better error
+  // messages.
+  if (Found.empty()) {
+    Found.clear(LookupOrdinaryName);
+    LookupName(Found, S);
+  }
+
+  // In Microsoft mode, if we are within a templated function and we can't
+  // resolve Identifier, then extend the SS with Identifier. This will have 
+  // the effect of resolving Identifier during template instantiation. 
+  // The goal is to be able to resolve a function call whose
+  // nested-name-specifier is located inside a dependent base class.
+  // Example: 
+  //
+  // class C {
+  // public:
+  //    static void foo2() {  }
+  // };
+  // template <class T> class A { public: typedef C D; };
+  //
+  // template <class T> class B : public A<T> {
+  // public:
+  //   void foo() { D::foo2(); }
+  // };
+  if (getLangOpts().MicrosoftExt) {
+    DeclContext *DC = LookupCtx ? LookupCtx : CurContext;
+    if (DC->isDependentContext() && DC->isFunctionOrMethod()) {
+      SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc);
+      return false;
+    }
+  }
+
+  unsigned DiagID;
+  if (!Found.empty())
+    DiagID = diag::err_expected_class_or_namespace;
+  else if (SS.isSet()) {
+    Diag(IdentifierLoc, diag::err_no_member) 
+      << &Identifier << LookupCtx << SS.getRange();
+    return true;
+  } else
+    DiagID = diag::err_undeclared_var_use;
+
+  if (SS.isSet())
+    Diag(IdentifierLoc, DiagID) << &Identifier << SS.getRange();
+  else
+    Diag(IdentifierLoc, DiagID) << &Identifier;
+
+  return true;
+}
+
+bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
+                                       IdentifierInfo &Identifier,
+                                       SourceLocation IdentifierLoc,
+                                       SourceLocation CCLoc,
+                                       ParsedType ObjectType,
+                                       bool EnteringContext,
+                                       CXXScopeSpec &SS) {
+  if (SS.isInvalid())
+    return true;
+  
+  return BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, CCLoc,
+                                     GetTypeFromParser(ObjectType),
+                                     EnteringContext, SS, 
+                                     /*ScopeLookupResult=*/0, false);
+}
+
+bool Sema::ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
+                                               const DeclSpec &DS,
+                                               SourceLocation ColonColonLoc) {
+  if (SS.isInvalid() || DS.getTypeSpecType() == DeclSpec::TST_error)
+    return true;
+
+  assert(DS.getTypeSpecType() == DeclSpec::TST_decltype);
+
+  QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
+  if (!T->isDependentType() && !T->getAs<TagType>()) {
+    Diag(DS.getTypeSpecTypeLoc(), diag::err_expected_class) 
+      << T << getLangOpts().CPlusPlus;
+    return true;
+  }
+
+  TypeLocBuilder TLB;
+  DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T);
+  DecltypeTL.setNameLoc(DS.getTypeSpecTypeLoc());
+  SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
+            ColonColonLoc);
+  return false;
+}
+
+/// IsInvalidUnlessNestedName - This method is used for error recovery
+/// purposes to determine whether the specified identifier is only valid as
+/// a nested name specifier, for example a namespace name.  It is
+/// conservatively correct to always return false from this method.
+///
+/// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
+bool Sema::IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
+                                     IdentifierInfo &Identifier, 
+                                     SourceLocation IdentifierLoc,
+                                     SourceLocation ColonLoc,
+                                     ParsedType ObjectType,
+                                     bool EnteringContext) {
+  if (SS.isInvalid())
+    return false;
+  
+  return !BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, ColonLoc,
+                                      GetTypeFromParser(ObjectType),
+                                      EnteringContext, SS, 
+                                      /*ScopeLookupResult=*/0, true);
+}
+
+bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
+                                       CXXScopeSpec &SS,
+                                       SourceLocation TemplateKWLoc,
+                                       TemplateTy Template,
+                                       SourceLocation TemplateNameLoc,
+                                       SourceLocation LAngleLoc,
+                                       ASTTemplateArgsPtr TemplateArgsIn,
+                                       SourceLocation RAngleLoc,
+                                       SourceLocation CCLoc,
+                                       bool EnteringContext) {
+  if (SS.isInvalid())
+    return true;
+  
+  // Translate the parser's template argument list in our AST format.
+  TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
+  translateTemplateArguments(TemplateArgsIn, TemplateArgs);
+
+  if (DependentTemplateName *DTN = Template.get().getAsDependentTemplateName()){
+    // Handle a dependent template specialization for which we cannot resolve
+    // the template name.
+    assert(DTN->getQualifier()
+             == static_cast<NestedNameSpecifier*>(SS.getScopeRep()));
+    QualType T = Context.getDependentTemplateSpecializationType(ETK_None,
+                                                          DTN->getQualifier(),
+                                                          DTN->getIdentifier(),
+                                                                TemplateArgs);
+    
+    // Create source-location information for this type.
+    TypeLocBuilder Builder;
+    DependentTemplateSpecializationTypeLoc SpecTL
+      = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
+    SpecTL.setElaboratedKeywordLoc(SourceLocation());
+    SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
+    SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
+    SpecTL.setTemplateNameLoc(TemplateNameLoc);
+    SpecTL.setLAngleLoc(LAngleLoc);
+    SpecTL.setRAngleLoc(RAngleLoc);
+    for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
+      SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
+    
+    SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
+              CCLoc);
+    return false;
+  }
+  
+  
+  if (Template.get().getAsOverloadedTemplate() ||
+      isa<FunctionTemplateDecl>(Template.get().getAsTemplateDecl())) {
+    SourceRange R(TemplateNameLoc, RAngleLoc);
+    if (SS.getRange().isValid())
+      R.setBegin(SS.getRange().getBegin());
+      
+    Diag(CCLoc, diag::err_non_type_template_in_nested_name_specifier)
+      << Template.get() << R;
+    NoteAllFoundTemplates(Template.get());
+    return true;
+  }
+                                
+  // We were able to resolve the template name to an actual template. 
+  // Build an appropriate nested-name-specifier.
+  QualType T = CheckTemplateIdType(Template.get(), TemplateNameLoc, 
+                                   TemplateArgs);
+  if (T.isNull())
+    return true;
+
+  // Alias template specializations can produce types which are not valid
+  // nested name specifiers.
+  if (!T->isDependentType() && !T->getAs<TagType>()) {
+    Diag(TemplateNameLoc, diag::err_nested_name_spec_non_tag) << T;
+    NoteAllFoundTemplates(Template.get());
+    return true;
+  }
+
+  // Provide source-location information for the template specialization type.
+  TypeLocBuilder Builder;
+  TemplateSpecializationTypeLoc SpecTL
+    = Builder.push<TemplateSpecializationTypeLoc>(T);
+  SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
+  SpecTL.setTemplateNameLoc(TemplateNameLoc);
+  SpecTL.setLAngleLoc(LAngleLoc);
+  SpecTL.setRAngleLoc(RAngleLoc);
+  for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
+    SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
+
+
+  SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
+            CCLoc);
+  return false;
+}
+
+namespace {
+  /// \brief A structure that stores a nested-name-specifier annotation,
+  /// including both the nested-name-specifier 
+  struct NestedNameSpecifierAnnotation {
+    NestedNameSpecifier *NNS;
+  };
+}
+
+void *Sema::SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS) {
+  if (SS.isEmpty() || SS.isInvalid())
+    return 0;
+  
+  void *Mem = Context.Allocate((sizeof(NestedNameSpecifierAnnotation) +
+                                                        SS.location_size()),
+                               llvm::alignOf<NestedNameSpecifierAnnotation>());
+  NestedNameSpecifierAnnotation *Annotation
+    = new (Mem) NestedNameSpecifierAnnotation;
+  Annotation->NNS = SS.getScopeRep();
+  memcpy(Annotation + 1, SS.location_data(), SS.location_size());
+  return Annotation;
+}
+
+void Sema::RestoreNestedNameSpecifierAnnotation(void *AnnotationPtr, 
+                                                SourceRange AnnotationRange,
+                                                CXXScopeSpec &SS) {
+  if (!AnnotationPtr) {
+    SS.SetInvalid(AnnotationRange);
+    return;
+  }
+  
+  NestedNameSpecifierAnnotation *Annotation
+    = static_cast<NestedNameSpecifierAnnotation *>(AnnotationPtr);
+  SS.Adopt(NestedNameSpecifierLoc(Annotation->NNS, Annotation + 1));
+}
+
+bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
+  assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
+
+  NestedNameSpecifier *Qualifier =
+    static_cast<NestedNameSpecifier*>(SS.getScopeRep());
+
+  // There are only two places a well-formed program may qualify a
+  // declarator: first, when defining a namespace or class member
+  // out-of-line, and second, when naming an explicitly-qualified
+  // friend function.  The latter case is governed by
+  // C++03 [basic.lookup.unqual]p10:
+  //   In a friend declaration naming a member function, a name used
+  //   in the function declarator and not part of a template-argument
+  //   in a template-id is first looked up in the scope of the member
+  //   function's class. If it is not found, or if the name is part of
+  //   a template-argument in a template-id, the look up is as
+  //   described for unqualified names in the definition of the class
+  //   granting friendship.
+  // i.e. we don't push a scope unless it's a class member.
+
+  switch (Qualifier->getKind()) {
+  case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Namespace:
+  case NestedNameSpecifier::NamespaceAlias:
+    // These are always namespace scopes.  We never want to enter a
+    // namespace scope from anything but a file context.
+    return CurContext->getRedeclContext()->isFileContext();
+
+  case NestedNameSpecifier::Identifier:
+  case NestedNameSpecifier::TypeSpec:
+  case NestedNameSpecifier::TypeSpecWithTemplate:
+    // These are never namespace scopes.
+    return true;
+  }
+
+  llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
+}
+
+/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
+/// scope or nested-name-specifier) is parsed, part of a declarator-id.
+/// After this method is called, according to [C++ 3.4.3p3], names should be
+/// looked up in the declarator-id's scope, until the declarator is parsed and
+/// ActOnCXXExitDeclaratorScope is called.
+/// The 'SS' should be a non-empty valid CXXScopeSpec.
+bool Sema::ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS) {
+  assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
+
+  if (SS.isInvalid()) return true;
+
+  DeclContext *DC = computeDeclContext(SS, true);
+  if (!DC) return true;
+
+  // Before we enter a declarator's context, we need to make sure that
+  // it is a complete declaration context.
+  if (!DC->isDependentContext() && RequireCompleteDeclContext(SS, DC))
+    return true;
+    
+  EnterDeclaratorContext(S, DC);
+
+  // Rebuild the nested name specifier for the new scope.
+  if (DC->isDependentContext())
+    RebuildNestedNameSpecifierInCurrentInstantiation(SS);
+
+  return false;
+}
+
+/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
+/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
+/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
+/// Used to indicate that names should revert to being looked up in the
+/// defining scope.
+void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
+  assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
+  if (SS.isInvalid())
+    return;
+  assert(!SS.isInvalid() && computeDeclContext(SS, true) &&
+         "exiting declarator scope we never really entered");
+  ExitDeclaratorContext(S);
+}