--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/gomp/pr84791.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,15 @@
+// PR c++/84791
+// { dg-do compile }
+
+typedef int I;
+
+template <int>
+void
+foo ()
+{
+  I i;
+  #pragma omp parallel reduction (I::I: i)	// { dg-error "'I' is not a class, namespace, or enumeration" "" { target c++11 } }
+    ;						// { dg-error "'I' is not a class or namespace" "" { target c++98_only } .-1 }
+}
+
+template void foo<0> ();