Fix false positive on anonymous namespaces in headers.

Summary:
Anynoumous namespaces inject a using directive into the AST to import
the names into the containing namespace.
We should not have them in headers, but there is another warning for
that.

Reviewers: djasper

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D8443

llvm-svn: 233087

clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.cpp

@@ -45,6 +45,16 @@ void GlobalNamesInHeadersCheck::check(const MatchFinder::MatchResult &Result) {
       return;
   }
 
+  if (const auto* UsingDirective = dyn_cast<UsingDirectiveDecl>(D)) {
+    if (UsingDirective->getNominatedNamespace()->isAnonymousNamespace()) {
+      // Anynoumous namespaces inject a using directive into the AST to import
+      // the names into the containing namespace.
+      // We should not have them in headers, but there is another warning for
+      // that.
+      return;
+    }
+  }
+
   diag(D->getLocStart(),
        "using declarations in the global namespace in headers are prohibited");
 }

clang-tools-extra/unittests/clang-tidy/GoogleModuleTest.cpp

@@ -101,6 +101,10 @@ TEST_F(GlobalNamesInHeadersCheckTest, UsingDirectives) {
   EXPECT_FALSE(runCheckOnCode("SOME_MACRO(namespace std);", "foo.h"));
 }
 
+TEST_F(GlobalNamesInHeadersCheckTest, RegressionAnonymousNamespace) {
+  EXPECT_FALSE(runCheckOnCode("namespace {}", "foo.h"));
+}
+
 } // namespace test
 } // namespace tidy
 } // namespace clang