diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -1212,7 +1212,7 @@
     return getPrimaryContext()->Encloses(DC);
 
   for (; DC; DC = DC->getParent())
-    if (DC->getPrimaryContext() == this)
+    if (!isa<LinkageSpecDecl>(DC) && DC->getPrimaryContext() == this)
       return true;
   return false;
 }
diff --git a/clang/test/SemaCXX/lookup-through-linkage.cpp b/clang/test/SemaCXX/lookup-through-linkage.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/SemaCXX/lookup-through-linkage.cpp
@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 %s -verify
+
+// expected-no-diagnostics
+
+extern "C++" {
+namespace A {
+namespace B {
+int bar;
+}
+} // namespace A
+namespace C {
+void foo() {
+  using namespace A;
+  (void)B::bar;
+}
+} // namespace C
+}
+
+extern "C" {
+extern "C++" {
+namespace D {
+namespace E {
+int bar;
+}
+} // namespace A
+namespace F {
+void foo() {
+  using namespace D;
+  (void)E::bar;
+}
+} // namespace C
+}
+}