Test Trac #7477

testsuite/tests/th/T7477.hs

+{-# LANGUAGE DataKinds, KindSignatures, PolyKinds, TypeFamilies, TemplateHaskell #-}
+
+module T7477 where
+
+import Language.Haskell.TH
+
+type family F (a :: k)
+type instance F Int = Bool
+
+$( do { info <- reifyInstances ''F [ConT ''Int]
+      ; reportWarning (pprint info)
+      ; return [] })

testsuite/tests/th/T7477.stderr

+
+T7477.hs:10:4: Warning:
+    type instance T7477.F GHC.Prim.* GHC.Types.Int = GHC.Types.Bool

testsuite/tests/th/all.T

@@ -304,3 +304,4 @@ test('T7667', normal, compile, ['-v0'])
 test('T7667a', normal, compile_fail, ['-v0'])
 test('T8455', normal, compile, ['-v0'])
 test('T8499', normal, compile, ['-v0'])
+test('T7477', normal, compile, ['-v0'])