1 files changed, 10 insertions, 0 deletions
diff --git a/testsuite/tests/gadt/T3638.hs b/testsuite/tests/gadt/T3638.hs
new file mode 100644
index 0000000000..abb6a86169
--- /dev/null
+++ b/testsuite/tests/gadt/T3638.hs
@@ -0,0 +1,10 @@
+{-# LANGUAGE GADTs #-}
+
+module T3638 where
+
+data T a where TInt :: T Int
+
+foo :: T Int -> Int
+foo TInt = 0
+
+{-# RULES "foo"  forall x. foo x = case x of { TInt -> 0 } #-}