Fix handling of redeclaration lookup for using declarations, where the prior

declaration is not visible. Previously we didn't find hidden friend names in
this redeclaration lookup, because we forgot to treat it as a redeclaration
lookup. Conversely, we did find some local extern names, but those don't
actually conflict with a namespace-scope using declaration, because the only
conflicts we can get are scope conflicts, not conflicts due to the entities
being members of the same namespace.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@206011 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 850db26e9afa02efdc682547856029bef2f1ac55..fbc3fd7eb8169c0297a3b657b32adbfaa0c1b911 100644 (file)
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -7379,6 +7379,13 @@ NamedDecl *Sema::BuildUsingDeclaration(Scope *S, AccessSpecifier AS,
       NamedDecl *D = F.next();
       if (!isDeclInScope(D, CurContext, S))
         F.erase();
+      // If we found a local extern declaration that's not ordinarily visible,
+      // and this declaration is being added to a non-block scope, ignore it.
+      // We're only checking for scope conflicts here, not also for violations
+      // of the linkage rules.
+      else if (!CurContext->isFunctionOrMethod() && D->isLocalExternDecl() &&
+               !(D->getIdentifierNamespace() & Decl::IDNS_Ordinary))
+        F.erase();
     }
     F.done();
   } else {

diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index 39a1ceaa57ecc2a6c01b586bf0e48accd1bac2b7..172a07906da014fdf4d38c6b32ad72cefdcc29d4 100644 (file)
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -244,10 +244,11 @@ static inline unsigned getIDNS(Sema::LookupNameKind NameKind,
       IDNS = Decl::IDNS_Tag;
     }
     break;
+
   case Sema::LookupLabel:
     IDNS = Decl::IDNS_Label;
     break;
-      
+
   case Sema::LookupMemberName:
     IDNS = Decl::IDNS_Member;
     if (CPlusPlus)
@@ -263,8 +264,10 @@ static inline unsigned getIDNS(Sema::LookupNameKind NameKind,
     break;
 
   case Sema::LookupUsingDeclName:
-    IDNS = Decl::IDNS_Ordinary | Decl::IDNS_Tag
-         | Decl::IDNS_Member | Decl::IDNS_Using;
+    assert(Redeclaration && "should only be used for redecl lookup");
+    IDNS = Decl::IDNS_Ordinary | Decl::IDNS_Tag | Decl::IDNS_Member |
+           Decl::IDNS_Using | Decl::IDNS_TagFriend | Decl::IDNS_OrdinaryFriend |
+           Decl::IDNS_LocalExtern;
     break;
 
   case Sema::LookupObjCProtocolName:

diff --git a/test/SemaCXX/using-decl-1.cpp b/test/SemaCXX/using-decl-1.cpp
index 24d92f175c302d271df2a19869f4f1e69fdc17d3..21aa107e219d8b1b12026f85ef302bd66b2522c4 100644 (file)
--- a/test/SemaCXX/using-decl-1.cpp
+++ b/test/SemaCXX/using-decl-1.cpp
@@ -160,3 +160,37 @@ namespace M { }
 }
 using N::M::FFF; // expected-error {{no member named 'FFF' in namespace 'using_suggestion_val_dropped_nested_specifier::N::M'; did you mean 'N::FFF'?}}
 }
+
+namespace UsingDeclVsHiddenName {
+  namespace A {
+    enum HiddenTag1 {}; // expected-note {{previous use is here}}
+    enum HiddenTag2 {}; // expected-note {{target}}
+    int HiddenFn1; // expected-note {{target}}
+    int HiddenFn2; // expected-note {{target}}
+    int HiddenLocalExtern1;
+    int HiddenLocalExtern2;
+  }
+
+  namespace B {
+    using A::HiddenTag1;
+    using A::HiddenFn1; // expected-note {{using declaration}}
+    using A::HiddenLocalExtern1;
+
+    struct S {
+      friend struct HiddenTag1; // expected-error {{tag type that does not match previous}}
+      friend struct HiddenTag2; // expected-note {{conflicting declaration}}
+      friend void HiddenFn1(); // expected-error {{cannot befriend target of using declaration}}
+      friend void HiddenFn2(); // expected-note {{conflicting declaration}}
+      void f() {
+        // OK, these are not in the scope of namespace B, even though they're
+        // members of the namespace.
+        void HiddenLocalExtern1();
+        void HiddenLocalExtern2();
+      }
+    };
+
+    using A::HiddenTag2; // expected-error {{conflicts with declaration already in scope}}
+    using A::HiddenFn2; // expected-error {{conflicts with declaration already in scope}}
+    using A::HiddenLocalExtern2;
+  }
+}