1 files changed, 13 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_fail/T18398.hs b/testsuite/tests/typecheck/should_fail/T18398.hs
new file mode 100644
index 0000000000..80b21c715f
--- /dev/null
+++ b/testsuite/tests/typecheck/should_fail/T18398.hs
@@ -0,0 +1,13 @@
+{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies,
+             ExistentialQuantification, GADTSyntax, FlexibleContexts #-}
+{-# OPTIONS_GHC -ddump-types #-}
+
+module FloatFDs2 where
+
+class C a b | a -> b where
+  meth :: a -> b -> ()
+
+data Ex where
+  MkEx :: a -> Ex
+
+f x = (\y -> case x of MkEx _ -> meth x y, \z -> case x of MkEx _ -> meth x z)