X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;ds=sidebyside;f=compiler%2Ftypes%2FType.lhs;h=db90b8c828062c776604586e98437bd8226a0eb7;hb=fa56e2107bd1b097580fbd2cf2c5760a772cc402;hp=fd817956d23356001bbb09a08291ae30696a8a14;hpb=cd290fc88d35d5a32c994664baa56a5eae250e9e;p=ghc-hetmet.git

diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs
index fd81795..db90b8c 100644
--- a/compiler/types/Type.lhs
+++ b/compiler/types/Type.lhs
@@ -89,6 +89,7 @@ module Type (
 	mkTvSubst, mkOpenTvSubst, zipOpenTvSubst, zipTopTvSubst, mkTopTvSubst, notElemTvSubst,
 	getTvSubstEnv, setTvSubstEnv, getTvInScope, extendTvInScope,
  	extendTvSubst, extendTvSubstList, isInScope, composeTvSubst, zipTyEnv,
+        isEmptyTvSubst,
 
 	-- Performing substitution on types
 	substTy, substTys, substTyWith, substTheta, 
@@ -733,13 +734,17 @@ It doesn't change the uniques at all, just the print names.
 
 \begin{code}
 tidyTyVarBndr :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
-tidyTyVarBndr (tidy_env, subst) tyvar
+tidyTyVarBndr env@(tidy_env, subst) tyvar
   = case tidyOccName tidy_env (getOccName name) of
-      (tidy', occ') -> 	((tidy', subst'), tyvar')
-		    where
-			subst' = extendVarEnv subst tyvar tyvar'
-			tyvar' = setTyVarName tyvar name'
-			name'  = tidyNameOcc name occ'
+      (tidy', occ') -> ((tidy', subst'), tyvar'')
+	where
+	  subst' = extendVarEnv subst tyvar tyvar''
+	  tyvar' = setTyVarName tyvar name'
+	  name'  = tidyNameOcc name occ'
+		-- Don't forget to tidy the kind for coercions!
+	  tyvar'' | isCoVar tyvar = setTyVarKind tyvar' kind'
+		  | otherwise	  = tyvar'
+	  kind'  = tidyType env (tyVarKind tyvar)
   where
     name = tyVarName tyvar