Test Trac #9318

testsuite/tests/indexed-types/should_fail/T9318.hs

+{-# LANGUAGE TypeFamilies #-}
+
+module T9318 where
+
+type family F x
+type instance F Int = Bool
+
+foo :: F Int -> ()
+foo True = ()
+
+bar :: F Int -> ()
+bar 'x' = ()

testsuite/tests/indexed-types/should_fail/T9318.stderr

+
+T9318.hs:12:5:
+    Couldn't match type ‘Bool’ with ‘Char’
+    Expected type: F Int
+      Actual type: Char
+    In the pattern: 'x'
+    In an equation for ‘bar’: bar 'x' = ()

testsuite/tests/indexed-types/should_fail/all.T

@@ -131,3 +131,4 @@ test('BadSock', normal, compile_fail, [''])
 test('T9580', normal, multimod_compile_fail, ['T9580', ''])
 test('T9662', normal, compile_fail, [''])
 test('T7862', normal, compile_fail, [''])
+test('T9318', normal, compile_fail, [''])