1 files changed, 60 insertions, 0 deletions
diff --git a/testsuite/tests/indexed-types/should_fail/T4174.hs b/testsuite/tests/indexed-types/should_fail/T4174.hs
new file mode 100644
index 0000000000..784c0baa08
--- /dev/null
+++ b/testsuite/tests/indexed-types/should_fail/T4174.hs
@@ -0,0 +1,60 @@
+{-# LANGUAGE TypeFamilies, TypeOperators, EmptyDataDecls #-}
+
+module T4174 where
+
+data True
+data False
+
+data Minor1
+
+data GHC6'8 m
+data GHC6'10 m
+
+type family a :<=: b :: {-Bool-}*
+type instance GHC6'10 m1 :<=: GHC6'8 m2 = False
+
+type a :>=: b = b :<=: a
+
+data Way ghcVersion tablesNextToCode profiling threaded
+
+type family GHCVersion way :: {-GHCVersion-} *
+type instance GHCVersion (Way v n p t) = v
+
+type family Threaded way :: {-Bool-} *
+type instance Threaded (Way v n p t) = t
+
+data Field w s t
+data SmStep
+data RtsSpinLock
+
+field :: String -> m (Field w a b)
+field = undefined
+
+type family WayOf (m :: * -> *) :: *
+
+sync_large_objects :: (Monad m, 
+                       (GHCVersion (WayOf m) :>=: GHC6'10 Minor1) ~ True, 
+                       Threaded (WayOf m) ~ True) 
+                   => m (Field (WayOf m) SmStep RtsSpinLock)
+sync_large_objects = field "sync_large_objects"
+
+testcase :: Monad m => m (Field (Way (GHC6'8 minor) n t p) a b)
+testcase = sync_large_objects
+
+{- Wanted constraints from the occurrence of sync_large_objects
+
+   (WayOf m) ~ (Way (GHC6'8 minor) n t p)
+   a ~ SmStep
+   b ~ RtsSpinLock
+
+   Threaded (WayOf m) ~ True 
+     == Threaded (Way (GHC6'8 minor) n t p) ~ True 
+     == p ~ True   
+
+   (GHCVersion (WayOf m) :>=: GHC6'10 Minor1) ~ True, 
+     == (GHC6'10 Minor1 :<=: GHCVersion (WayOf m)) ~ True, 
+     == (GHC6'10 Minor1 :<=: GHCVersion (Way (GHC6'8 minor) n t p))) ~ True, 
+     == (GHC6'10 Minor1 :<=: GHC6'8 minor) ~ True
+     == False ~ True
+
+-}
+\ No newline at end of file