test/SemaCXX/warn-using-namespace-in-header.cpp

// RUN: %clang_cc1 -fsyntax-only -Wheader-hygiene -verify %s

#include "warn-using-namespace-in-header.h"

namespace dont_warn {}
using namespace dont_warn;

// Warning is actually in the header but only the cpp file gets scanned.
// expected-warning {{using namespace directive in global context in header}}