Make sure to zonk the kind of coercion variables

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

diff --git a/compiler/typecheck/TcHsSyn.lhs b/compiler/typecheck/TcHsSyn.lhs
index fe9c808..7e15770 100644 (file)
--- a/compiler/typecheck/TcHsSyn.lhs
+++ b/compiler/typecheck/TcHsSyn.lhs
@@ -251,11 +251,22 @@ zonkDictBndrs :: ZonkEnv -> [Var] -> TcM [Var]
 zonkDictBndrs env ids = mappM (zonkDictBndr env) ids
 
 zonkDictBndr :: ZonkEnv -> Var -> TcM Var
-zonkDictBndr env var | isTyVar var = return var
+zonkDictBndr env var | isTyVar var = zonkTyVarBndr env var
                     | otherwise   = zonkIdBndr env var
 
 zonkTopBndrs :: [TcId] -> TcM [Id]
 zonkTopBndrs ids = zonkIdBndrs emptyZonkEnv ids
+
+-- Zonk the kind of a non-TC tyvar in case it is a coercion variable (their
+-- kind contains types).
+--
+zonkTyVarBndr :: ZonkEnv -> TyVar -> TcM TyVar
+zonkTyVarBndr env tv
+  | isCoVar tv
+  = do { kind <- zonkTcTypeToType env (tyVarKind tv)
+       ; return $ setTyVarKind tv kind
+       }
+  | otherwise = return tv
 \end{code}
 
 
@@ -607,7 +618,8 @@ zonkCoFn env (WpLam id)     = do { id' <- zonkDictBndr env id
                                 ; let env1 = extendZonkEnv1 env id'
                                 ; return (env1, WpLam id') }
 zonkCoFn env (WpTyLam tv)   = ASSERT( isImmutableTyVar tv )
-                             return (env, WpTyLam tv)
+                              do { tv' <- zonkTyVarBndr env tv
+                                ; return (env, WpTyLam tv') }
 zonkCoFn env (WpApp v)
        | isTcTyVar v       = do { co <- zonkTcTyVar v
                                 ; return (env, WpTyApp co) }