1 files changed, 15 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/ext/is_base_of_diagnostic.C b/gcc/testsuite/g++.dg/ext/is_base_of_diagnostic.C
new file mode 100644
index 000000000..8cb1ce38f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_base_of_diagnostic.C
@@ -0,0 +1,15 @@
+class A
+{ };
+
+class B;
+
+union C
+{ };
+
+union D;
+
+void f()
+{
+  __is_base_of(A, B);  // { dg-error "incomplete type" }
+  __is_base_of(C, D);  
+}