1 files changed, 32 insertions, 0 deletions
diff --git a/testsuite/tests/simplCore/should_compile/T5168.hs b/testsuite/tests/simplCore/should_compile/T5168.hs
new file mode 100644
index 0000000000..22b4349fa2
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+++ b/testsuite/tests/simplCore/should_compile/T5168.hs
@@ -0,0 +1,32 @@
+-- In this test we do -ddump-simpl, and grep for 'patError.
+-- We expect *not* to see patError in the output
+-- because the branch is inaccessible.  
+-- In GHC 7.0 and earlier, we did get a patError in the output program.
+
+{-# LANGUAGE TypeFamilies, GADTs #-}
+module NoMatch where
+
+data Tag
+data TagExtra
+
+--------
+
+data Foo a where
+  Foo :: String -> Foo a
+  FooExtra :: Int -> Foo TagExtra
+
+-- The cmm code for fooName does not match against 'FooExtra'
+fooName :: Foo Tag -> String
+fooName (Foo s) = s
+
+--------
+
+data Bar a where
+  Bar :: String -> Bar a
+  BarExtra :: a ~ TagExtra => Int -> Bar a
+
+-- The cmm code for barName will try to pattern-match against 'BarExtra'
+barName :: Bar Tag -> String
+barName (Bar s) = s
+
+