1 files changed, 14 insertions, 0 deletions
diff --git a/testsuite/tests/numeric/should_run/T10011.hs b/testsuite/tests/numeric/should_run/T10011.hs
new file mode 100644
index 0000000000..91a0ecdba8
--- /dev/null
+++ b/testsuite/tests/numeric/should_run/T10011.hs
@@ -0,0 +1,14 @@
+{-# LANGUAGE ScopedTypeVariables, TypeOperators, GADTs #-}
+module Main
+       ( main -- :: IO ()
+       ) where
+import Data.Data
+import Data.Ratio
+
+main :: IO ()
+main =
+  let bad = gmapT (\(x :: b) ->
+              case eqT :: Maybe (b :~: Integer) of
+                Nothing -> x;
+                Just Refl -> x * 2) (1 % 2) :: Rational
+  in print (bad == numerator bad % denominator bad)