1 files changed, 16 insertions, 0 deletions
diff --git a/testsuite/tests/mdo/should_fail/mdofail001.hs b/testsuite/tests/mdo/should_fail/mdofail001.hs
new file mode 100644
index 0000000000..fe8f95e766
--- /dev/null
+++ b/testsuite/tests/mdo/should_fail/mdofail001.hs
@@ -0,0 +1,16 @@
+{-# OPTIONS -XRecursiveDo #-}
+
+-- let bindings are monomorphic if used prior to their definition
+
+module Main (main) where
+
+import Control.Monad.Fix 
+
+t :: IO (Int, Int)
+t = mdo x <- return (l "1", l [1,2,3])
+        let l [] = 0
+            l (x:xs) = 1 + l xs
+        return x
+
+main :: IO ()
+main = t >>= print