From: simonpj@microsoft.com <unknown>
Date: Wed, 11 Aug 2010 14:35:55 +0000 (+0000)
Subject: Remember to zonk FlatSkols!
X-Git-Tag: 2010-11-18~391
X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=9d193eceb5f287ac3dfa90b40e22d9c992cf9f66

Remember to zonk FlatSkols!
---

diff --git a/compiler/typecheck/TcMType.lhs b/compiler/typecheck/TcMType.lhs
index 492cbf9..d5c794b 100644
--- a/compiler/typecheck/TcMType.lhs
+++ b/compiler/typecheck/TcMType.lhs
@@ -946,14 +946,14 @@ zonkType unbound_var_fn ty
 zonk_tc_tyvar :: (TcTyVar -> TcM Type)	-- What to do for an unbound mutable var
  	      -> TcTyVar -> TcM TcType
 zonk_tc_tyvar unbound_var_fn tyvar 
-  | not (isMetaTyVar tyvar)	-- Skolems
-  = return (TyVarTy tyvar)
-
-  | otherwise			-- Mutables
-  = do	{ cts <- readMetaTyVar tyvar
-	; case cts of
-	    Flexi       -> unbound_var_fn tyvar    -- Unbound meta type variable
-	    Indirect ty -> zonkType unbound_var_fn ty  }
+  = ASSERT( isTcTyVar tyvar )
+    case tcTyVarDetails tyvar of
+      SkolemTv {}  -> return (TyVarTy tyvar)
+      FlatSkol ty  -> zonkType unbound_var_fn ty
+      MetaTv _ ref -> do { cts <- readMutVar ref
+			 ; case cts of    
+			     Flexi       -> unbound_var_fn tyvar  
+			     Indirect ty -> zonkType unbound_var_fn ty  }
 
 -- Zonk the kind of a non-TC tyvar in case it is a coercion variable (their
 -- kind contains types).