Model NamespaceAliasDecls as having their nominated namespace as an underlying

declaration. This fixes an issue where we would reject (due to a claimed
ambiguity) a case where lookup finds multiple NamespaceAliasDecls from
different scopes that nominate the same namespace.

The C++ standard doesn't make it clear that such a case is in fact valid (which
I'm working on fixing), but there are no relevant rules that distinguish using
declarations and namespace alias declarations here, so it makes sense to treat
them the same way.

llvm-svn: 256601

1 files changed, 7 insertions, 10 deletions

diff --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index 5aa5fc5ebde..21cf6258514 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -494,6 +494,7 @@ bool ResultBuilder::isInterestingDecl(const NamedDecl *ND,
                                       bool &AsNestedNameSpecifier) const {
   AsNestedNameSpecifier = false;
 
+  auto *Named = ND;
   ND = ND->getUnderlyingDecl();
 
   // Skip unnamed entities.
@@ -526,14 +527,14 @@ bool ResultBuilder::isInterestingDecl(const NamedDecl *ND,
         return false;
 
   if (Filter == &ResultBuilder::IsNestedNameSpecifier ||
-      ((isa<NamespaceDecl>(ND) || isa<NamespaceAliasDecl>(ND)) &&
+      (isa<NamespaceDecl>(ND) &&
        Filter != &ResultBuilder::IsNamespace &&
        Filter != &ResultBuilder::IsNamespaceOrAlias &&
        Filter != nullptr))
     AsNestedNameSpecifier = true;
 
   // Filter out any unwanted results.
-  if (Filter && !(this->*Filter)(ND)) {
+  if (Filter && !(this->*Filter)(Named)) {
     // Check whether it is interesting as a nested-name-specifier.
     if (AllowNestedNameSpecifiers && SemaRef.getLangOpts().CPlusPlus && 
         IsNestedNameSpecifier(ND) &&
@@ -1142,14 +1143,12 @@ bool ResultBuilder::IsNamespace(const NamedDecl *ND) const {
 /// \brief Determines whether the given declaration is a namespace or 
 /// namespace alias.
 bool ResultBuilder::IsNamespaceOrAlias(const NamedDecl *ND) const {
-  return isa<NamespaceDecl>(ND) || isa<NamespaceAliasDecl>(ND);
+  return isa<NamespaceDecl>(ND->getUnderlyingDecl());
 }
 
 /// \brief Determines whether the given declaration is a type.
 bool ResultBuilder::IsType(const NamedDecl *ND) const {
-  if (const UsingShadowDecl *Using = dyn_cast<UsingShadowDecl>(ND))
-    ND = Using->getTargetDecl();
-  
+  ND = ND->getUnderlyingDecl();
   return isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND);
 }
 
@@ -1157,11 +1156,9 @@ bool ResultBuilder::IsType(const NamedDecl *ND) const {
 /// "." or "->".  Only value declarations, nested name specifiers, and
 /// using declarations thereof should show up.
 bool ResultBuilder::IsMember(const NamedDecl *ND) const {
-  if (const UsingShadowDecl *Using = dyn_cast<UsingShadowDecl>(ND))
-    ND = Using->getTargetDecl();
-
+  ND = ND->getUnderlyingDecl();
   return isa<ValueDecl>(ND) || isa<FunctionTemplateDecl>(ND) ||
-    isa<ObjCPropertyDecl>(ND);
+         isa<ObjCPropertyDecl>(ND);
 }
 
 static bool isObjCReceiverType(ASTContext &C, QualType T) {