Cleaned up version of Tom's unflattened skolemOccurs

[ghc-hetmet.git] / compiler / types / Coercion.lhs

diff --git a/compiler/types/Coercion.lhs b/compiler/types/Coercion.lhs
index fa4a6b7..770988d 100644 (file)
--- a/compiler/types/Coercion.lhs
+++ b/compiler/types/Coercion.lhs
@@ -371,7 +371,10 @@ transCoercionTyCon =
   where
     composeCoercionKindsOf (co1:co2:rest)
       = ASSERT( null rest )
-        WARN( not (r1 `coreEqType` a2), text "Strange! Type mismatch in trans coercion, probably a bug")
+        WARN( not (r1 `coreEqType` a2), 
+              text "Strange! Type mismatch in trans coercion, probably a bug"
+              $$
+              ppr r1 <+> text "=/=" <+> ppr a2)
         (a1, r2)
       where
         (a1, r1) = coercionKind co1