Test Trac #9222

testsuite/tests/polykinds/T9222.hs

+{-# LANGUAGE RankNTypes, GADTs, DataKinds, PolyKinds, TypeOperators, TypeFamilies #-}
+module T9222 where
+
+import Data.Proxy
+
+data Want :: (i,j) -> * where
+  Want :: (a ~ '(b,c) => Proxy b) -> Want a

testsuite/tests/polykinds/all.T

@@ -102,3 +102,4 @@ test('T8705', normal, compile, [''])
 test('T8985', normal, compile, [''])
 test('T9106', normal, compile_fail, [''])
 test('T9144', normal, compile_fail, [''])
+test('T9222', normal, compile, [''])