From a64c1e5452dea9d227276c21e5457ccd30a202c1 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Tue, 8 Dec 2009 15:38:36 +0000
Subject: [PATCH] When performing unqualified name lookup in C++, don't look
 directly into transparent contexts; instead, we'll look into their nearest
 enclosing non-transparent contexts further up the stack. Fixes PR5479.

llvm-svn: 90859
---
 clang/lib/Sema/SemaLookup.cpp          |  7 ++++++-
 clang/test/SemaCXX/linkage-spec.cpp    | 14 ++++++++++++++
 clang/test/SemaCXX/using-directive.cpp |  9 +++++++++
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 1ddfef839fd6..48d7320d2e96 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -480,7 +480,12 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
       DeclContext *OuterCtx = findOuterContext(S);
       for (; Ctx && Ctx->getPrimaryContext() != OuterCtx; 
            Ctx = Ctx->getLookupParent()) {
-        if (Ctx->isFunctionOrMethod())
+        // We do not directly look into function or method contexts
+        // (since all local variables are found via the identifier
+        // changes) or in transparent contexts (since those entities
+        // will be found in the nearest enclosing non-transparent
+        // context).
+        if (Ctx->isFunctionOrMethod() || Ctx->isTransparentContext())
           continue;
         
         // Perform qualified name lookup into this context.
diff --git a/clang/test/SemaCXX/linkage-spec.cpp b/clang/test/SemaCXX/linkage-spec.cpp
index fc9b3ab51ead..d19727ac0766 100644
--- a/clang/test/SemaCXX/linkage-spec.cpp
+++ b/clang/test/SemaCXX/linkage-spec.cpp
@@ -40,3 +40,17 @@ namespace pr5430 {
 }
 using namespace pr5430;
 extern "C" void pr5430::func(void) { }
+
+// PR5404
+int f2(char *)
+{
+        return 0;
+}
+
+extern "C"
+{
+    int f2(int)
+    {
+        return f2((char *)0);
+    }
+}
diff --git a/clang/test/SemaCXX/using-directive.cpp b/clang/test/SemaCXX/using-directive.cpp
index 51f347dc7a73..b7583f27cb64 100644
--- a/clang/test/SemaCXX/using-directive.cpp
+++ b/clang/test/SemaCXX/using-directive.cpp
@@ -112,3 +112,12 @@ using namespace Alias;
 void testAlias() {
   inAliased();
 }
+
+namespace N { void f2(int); }
+
+extern "C++" {
+  using namespace N;
+  void f3() { f2(1); }
+}
+
+void f4() { f2(1); }