Test Trac #8931

(cherry picked from commit 8bf8ce1e)

testsuite/tests/ghci/scripts/T8931.script

+:m +Data.Typeable
+let {f :: Typeable a => (a->Bool) -> Bool; f _ = True}
+f (\x -> (x == 3))

testsuite/tests/ghci/scripts/T8931.stdout

+True

testsuite/tests/ghci/scripts/all.T

@@ -169,3 +169,4 @@ test('T8696', normal, ghci_script, ['T8696.script'])
 test('T8776', normal, ghci_script, ['T8776.script'])
 test('T8831', normal, ghci_script, ['T8831.script'])
 test('T8917', normal, ghci_script, ['T8917.script'])
+test('T8931', normal, ghci_script, ['T8931.script'])