1 files changed, 63 insertions, 0 deletions
diff --git a/testsuite/tests/perf/compiler/T3064.hs b/testsuite/tests/perf/compiler/T3064.hs
new file mode 100644
index 0000000000..328da45976
--- /dev/null
+++ b/testsuite/tests/perf/compiler/T3064.hs
@@ -0,0 +1,63 @@
+{-# LANGUAGE Rank2Types, TypeSynonymInstances, FlexibleInstances #-}
+{-# LANGUAGE TypeFamilies, GeneralizedNewtypeDeriving #-}
+module Bug2 where
+
+newtype ReaderT r m a = ReaderT { runReaderT :: r -> m a }
+
+instance (Monad m) => Monad (ReaderT r m) where
+    return a = ReaderT $ \_ -> return a
+    m >>= k  = ReaderT $ \r -> do
+        a <- runReaderT m r
+        runReaderT (k a) r
+    fail msg = ReaderT $ \_ -> fail msg
+
+newtype ResourceT r s m v = ResourceT { unResourceT :: ReaderT r m v }
+  deriving (Monad)
+
+data Ctx = Ctx
+
+data Ch = Ch
+
+type CAT s c = ResourceT [Ch] (s,c)
+
+type CtxM c = ResourceT Ctx c IO
+
+newtype CA s c v = CA { unCA :: CAT s c (CtxM c) v }
+  deriving (Monad)
+
+class (Monad m) => MonadCA m where
+  type CtxLabel m
+
+instance MonadCA (CA s c) where
+  type CtxLabel (CA s c) = c
+
+instance (Monad m, MonadCA m, c ~ CtxLabel m) => MonadCA  (CAT s c m) where
+  type CtxLabel (CAT s c m) = c
+
+runCAT :: (forall s. CAT s c m v) -> m v
+runCAT action = runReaderT (unResourceT action) []
+
+newRgn :: MonadCA m => (forall s. CAT s (CtxLabel m) m v) -> m v
+newRgn = runCAT
+
+runCA :: (forall s c. CA s c v) -> IO v
+runCA action = runCtxM (runCAT (unCA action))
+
+runCtxM :: (forall c. CtxM c v) -> IO v
+runCtxM action = runReaderT (unResourceT action) Ctx
+
+-- test11 :: IO ()
+-- test11 = runCA(newRgn(newRgn(newRgn(newRgn(newRgn(
+--   newRgn(newRgn(newRgn(newRgn(return()))))))))))
+
+-- test12 :: IO ()
+-- test12 = runCA(newRgn(newRgn(newRgn(newRgn(newRgn(newRgn(
+--   newRgn(newRgn(newRgn(newRgn(return())))))))))))
+
+-- test13 :: IO ()
+-- test13 = runCA(newRgn(newRgn(newRgn(newRgn(newRgn(newRgn(newRgn(
+--   newRgn(newRgn(newRgn(newRgn(return()))))))))))))
+
+test14 :: IO ()
+test14 = runCA(newRgn(newRgn(newRgn(newRgn(newRgn(newRgn(newRgn(newRgn(
+  newRgn(newRgn(newRgn(newRgn(return())))))))))))))