When we need the complete set of visible declarations from a
declaration context, check whether the primary context---not the
current context---has any external visible declarations. Fixes
PR13616.

llvm-svn: 162083
diff --git a/clang/test/Index/complete-preamble.h b/clang/test/Index/complete-preamble.h
new file mode 100644
index 0000000..e696284
--- /dev/null
+++ b/clang/test/Index/complete-preamble.h
@@ -0,0 +1,6 @@
+namespace std {
+  void wibble();
+}
+
+namespace std {
+}