[project @ 2002-02-07 12:51:34 by simonpj]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcUnify.lhs

diff --git a/ghc/compiler/typecheck/TcUnify.lhs b/ghc/compiler/typecheck/TcUnify.lhs
index 6b74930..8ee07bc 100644 (file)
--- a/ghc/compiler/typecheck/TcUnify.lhs
+++ b/ghc/compiler/typecheck/TcUnify.lhs
@@ -637,19 +637,18 @@ uUnboundVar swapped tv1 maybe_ty1 ps_ty2 non_var_ty2
 
 checkKinds swapped tv1 ty2
 -- We're about to unify a type variable tv1 with a non-tyvar-type ty2.
--- ty2 has been zonked at this stage
+-- ty2 has been zonked at this stage.
 
-  | tk1 `eqKind` liftedTypeKind && tk2 `eqKind` unliftedTypeKind
-       -- Check that we don't unify a lifted type variable with an
-       -- unlifted type: e.g.  (id 3#) is illegal
+  | tk2 `hasMoreBoxityInfo` tk1 = returnTc ()
+
+  | otherwise
+       -- Either the kinds aren't compatible
+       --      (can happen if we unify (a b) with (c d))
+       -- or we are unifying a lifted type variable with an
+       --      unlifted type: e.g.  (id 3#) is illegal
   = tcAddErrCtxtM (unifyKindCtxt swapped tv1 ty2)      $
     unifyMisMatch k1 k2
 
-  | otherwise
-  =    -- Check that we aren't losing boxity info (shouldn't happen)
-    WARN (not (tk2 `hasMoreBoxityInfo` tk1),
-         (ppr tv1 <+> ppr tk1) $$ (ppr ty2 <+> ppr tk2))
-    returnTc ()
   where
     (k1,k2) | swapped   = (tk2,tk1)
            | otherwise = (tk1,tk2)