Test #10770

testsuite/tests/typecheck/should_compile/T10770a.hs

+module T10770a where
+
+import Data.Typeable
+
+main = print $ foo $ Just ()
+
+foo :: Typeable (t a) => t a -> String
+foo x = let k = show $ typeOf x in k

testsuite/tests/typecheck/should_compile/T10770b.hs

+{-# LANGUAGE FlexibleContexts #-}
+{-# OPTIONS_GHC -fwarn-redundant-constraints #-}
+module T10770b where
+
+f :: (Show a, Show (Maybe a)) => Maybe a -> String
+f x = let k = show x in k
+
+g :: (Show a, Show (Maybe a)) => Maybe a -> String
+g x = show x

testsuite/tests/typecheck/should_compile/all.T

@@ -475,3 +475,5 @@ test('T10642', normal, compile, [''])
 test('T10744', normal, compile, [''])
 test('update-existential', normal, compile, [''])
 test('T10347', expect_broken(10347), compile, [''])
+test('T10770a', expect_broken(10770), compile, [''])
+test('T10770b', expect_broken(10770), compile, [''])