fix UsingNamespaceInHeaderCheck

Author: guwirth

cxx-checks/src/main/java/org/sonar/cxx/checks/UsingNamespaceInHeaderCheck.java

@@ -68,10 +68,14 @@ public void visitFile(AstNode astNode) {
   @Override
   public void visitNode(AstNode node) {
     if (isHeader) {
-      final boolean containsNamespace = node.getChildren().stream()
-        .anyMatch(childNode -> CxxKeyword.NAMESPACE.equals(childNode.getToken().getType()));
-      if (containsNamespace) {
-        getContext().createLineViolation(this, "Using namespace are not allowed in header files.", node);
+      // declaration directly in translation unit
+      if (node.getParent().is(CxxGrammarImpl.declaration)
+        && node.getParent().getParent().is(CxxGrammarImpl.translationUnit)) {
+        final boolean containsNamespace = node.getChildren().stream()
+          .anyMatch(childNode -> CxxKeyword.NAMESPACE.equals(childNode.getToken().getType()));
+        if (containsNamespace) {
+          getContext().createLineViolation(this, "Using namespace are not allowed in header files.", node);
+        }
       }
     }
   }

cxx-checks/src/test/resources/checks/UsingNamespaceInHeader.h

@@ -8,7 +8,7 @@ namespace Foo
     void fooFunc( );
 }
 
-using namespace std;
+using namespace std; // error
 
 // alias for types or template shall not be detected
 // see more details http://en.cppreference.com/w/cpp/language/type_alias
@@ -30,3 +30,13 @@ namespace Foo
         privateFunction( );
     }
 }
+
+void fooFunc()
+{
+    using namespace std;
+}
+
+namespace X
+{
+    using namespace std;
+};