1 files changed, 45 insertions, 28 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 7be71ca49ea2..3c58f1d19c04 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -372,6 +372,7 @@ ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
   }
 
   NamedDecl *IIDecl = nullptr;
+  UsingShadowDecl *FoundUsingShadow = nullptr;
   switch (Result.getResultKind()) {
   case LookupResult::NotFound:
   case LookupResult::NotFoundInCurrentInstantiation:
@@ -441,8 +442,10 @@ ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
           (AllowDeducedTemplate && getAsTypeTemplateDecl(RealRes))) {
         if (!IIDecl ||
             // Make the selection of the recovery decl deterministic.
-            RealRes->getLocation() < IIDecl->getLocation())
+            RealRes->getLocation() < IIDecl->getLocation()) {
           IIDecl = RealRes;
+          FoundUsingShadow = dyn_cast<UsingShadowDecl>(*Res);
+        }
       }
     }
 
@@ -465,6 +468,7 @@ ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
 
   case LookupResult::Found:
     IIDecl = Result.getFoundDecl();
+    FoundUsingShadow = dyn_cast<UsingShadowDecl>(*Result.begin());
     break;
   }
 
@@ -491,14 +495,20 @@ ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
     (void)DiagnoseUseOfDecl(IDecl, NameLoc);
     if (!HasTrailingDot)
       T = Context.getObjCInterfaceType(IDecl);
+    FoundUsingShadow = nullptr; // FIXME: Target must be a TypeDecl.
   } else if (auto *UD = dyn_cast<UnresolvedUsingIfExistsDecl>(IIDecl)) {
     (void)DiagnoseUseOfDecl(UD, NameLoc);
     // Recover with 'int'
     T = Context.IntTy;
+    FoundUsingShadow = nullptr;
   } else if (AllowDeducedTemplate) {
-    if (auto *TD = getAsTypeTemplateDecl(IIDecl))
+    if (auto *TD = getAsTypeTemplateDecl(IIDecl)) {
+      // FIXME: TemplateName should include FoundUsingShadow sugar.
       T = Context.getDeducedTemplateSpecializationType(TemplateName(TD),
                                                        QualType(), false);
+      // Don't wrap in a further UsingType.
+      FoundUsingShadow = nullptr;
+    }
   }
 
   if (T.isNull()) {
@@ -507,6 +517,9 @@ ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
     return nullptr;
   }
 
+  if (FoundUsingShadow)
+    T = Context.getUsingType(FoundUsingShadow, T);
+
   // NOTE: avoid constructing an ElaboratedType(Loc) if this is a
   // constructor or destructor name (in such a case, the scope specifier
   // will be attached to the enclosing Expr or Decl node).
@@ -843,21 +856,6 @@ static bool isTagTypeWithMissingTag(Sema &SemaRef, LookupResult &Result,
   return false;
 }
 
-/// Build a ParsedType for a simple-type-specifier with a nested-name-specifier.
-static ParsedType buildNestedType(Sema &S, CXXScopeSpec &SS,
-                                  QualType T, SourceLocation NameLoc) {
-  ASTContext &Context = S.Context;
-
-  TypeLocBuilder Builder;
-  Builder.pushTypeSpec(T).setNameLoc(NameLoc);
-
-  T = S.getElaboratedType(ETK_None, SS, T);
-  ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
-  ElabTL.setElaboratedKeywordLoc(SourceLocation());
-  ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
-  return S.CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
-}
-
 Sema::NameClassification Sema::ClassifyName(Scope *S, CXXScopeSpec &SS,
                                             IdentifierInfo *&Name,
                                             SourceLocation NameLoc,
@@ -1134,14 +1132,28 @@ Corrected:
                          : NameClassification::TypeTemplate(Template);
   }
 
+  auto BuildTypeFor = [&](TypeDecl *Type, NamedDecl *Found) {
+    QualType T = Context.getTypeDeclType(Type);
+    if (const auto *USD = dyn_cast<UsingShadowDecl>(Found))
+      T = Context.getUsingType(USD, T);
+
+    if (SS.isEmpty()) // No elaborated type, trivial location info
+      return ParsedType::make(T);
+
+    TypeLocBuilder Builder;
+    Builder.pushTypeSpec(T).setNameLoc(NameLoc);
+    T = getElaboratedType(ETK_None, SS, T);
+    ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
+    ElabTL.setElaboratedKeywordLoc(SourceLocation());
+    ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
+    return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
+  };
+
   NamedDecl *FirstDecl = (*Result.begin())->getUnderlyingDecl();
   if (TypeDecl *Type = dyn_cast<TypeDecl>(FirstDecl)) {
     DiagnoseUseOfDecl(Type, NameLoc);
     MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
-    QualType T = Context.getTypeDeclType(Type);
-    if (SS.isNotEmpty())
-      return buildNestedType(*this, SS, T, NameLoc);
-    return ParsedType::make(T);
+    return BuildTypeFor(Type, *Result.begin());
   }
 
   ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(FirstDecl);
@@ -1190,10 +1202,7 @@ Corrected:
       isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
     TypeDecl *Type = Result.getAsSingle<TypeDecl>();
     DiagnoseUseOfDecl(Type, NameLoc);
-    QualType T = Context.getTypeDeclType(Type);
-    if (SS.isNotEmpty())
-      return buildNestedType(*this, SS, T, NameLoc);
-    return ParsedType::make(T);
+    return BuildTypeFor(Type, *Result.begin());
   }
 
   // If we already know which single declaration is referenced, just annotate
@@ -8504,7 +8513,14 @@ static NamedDecl *DiagnoseInvalidRedeclaration(
         << NewFD->getParamDecl(Idx - 1)->getType();
     } else if (FDisConst != NewFDisConst) {
       SemaRef.Diag(FD->getLocation(), diag::note_member_def_close_const_match)
-          << NewFDisConst << FD->getSourceRange().getEnd();
+          << NewFDisConst << FD->getSourceRange().getEnd()
+          << (NewFDisConst
+                  ? FixItHint::CreateRemoval(ExtraArgs.D.getFunctionTypeInfo()
+                                                 .getConstQualifierLoc())
+                  : FixItHint::CreateInsertion(ExtraArgs.D.getFunctionTypeInfo()
+                                                   .getRParenLoc()
+                                                   .getLocWithOffset(1),
+                                               " const"));
     } else
       SemaRef.Diag(FD->getLocation(),
                    IsMember ? diag::note_member_def_close_match
@@ -9195,6 +9211,7 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
             << Name << RemoveRange
             << FixItHint::CreateRemoval(RemoveRange)
             << FixItHint::CreateInsertion(InsertLoc, "<>");
+          Invalid = true;
         }
       }
     } else {
@@ -15359,7 +15376,7 @@ bool Sema::CheckEnumUnderlyingType(TypeSourceInfo *TI) {
     if (BT->isInteger())
       return false;
 
-  if (T->isExtIntType())
+  if (T->isBitIntType())
     return false;
 
   return Diag(UnderlyingLoc, diag::err_enum_invalid_underlying) << T;
@@ -18277,7 +18294,7 @@ static void CheckForDuplicateEnumValues(Sema &S, ArrayRef<Decl *> Elements,
 
     // Emit one note for each of the remaining enum constants with
     // the same value.
-    for (auto *ECD : llvm::make_range(Vec->begin() + 1, Vec->end()))
+    for (auto *ECD : llvm::drop_begin(*Vec))
       S.Diag(ECD->getLocation(), diag::note_duplicate_element)
         << ECD << toString(ECD->getInitVal(), 10)
         << ECD->getSourceRange();