When declaring a namespace alias, ignore previous declarations that

aren't in scope. Fixes PR7014.

llvm-svn: 102915

clang/lib/Sema/SemaDeclCXX.cpp

@@ -4004,9 +4004,13 @@ Sema::DeclPtrTy Sema::ActOnNamespaceAliasDef(Scope *S,
   LookupParsedName(R, S, &SS);
 
   // Check if we have a previous declaration with the same name.
-  if (NamedDecl *PrevDecl
-        = LookupSingleName(S, Alias, AliasLoc, LookupOrdinaryName, 
-                           ForRedeclaration)) {
+  NamedDecl *PrevDecl
+    = LookupSingleName(S, Alias, AliasLoc, LookupOrdinaryName, 
+                       ForRedeclaration);
+  if (PrevDecl && !isDeclInScope(PrevDecl, CurContext, S))
+    PrevDecl = 0;
+
+  if (PrevDecl) {
     if (NamespaceAliasDecl *AD = dyn_cast<NamespaceAliasDecl>(PrevDecl)) {
       // We already have an alias with the same name that points to the same
       // namespace, so don't create a new one.

clang/test/SemaCXX/namespace-alias.cpp

@@ -91,3 +91,13 @@ namespace A = N;
 
 A::X nx;
 
+namespace PR7014 {
+  namespace X
+  {
+    namespace Y {}
+  }
+
+  using namespace X;
+
+  namespace Y = X::Y;
+}