X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcType.lhs;h=74100920bbf1aa4dea009b7a3b35d9c715edd1d4;hb=25bff7fe1a22edbafa188af8d844c67057fa5eb8;hp=b20d32eec3a04810a22f513a53170575816ff62c;hpb=27225b0c9f799a251c96242f502e8cfd6bf76d7c;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcType.lhs b/compiler/typecheck/TcType.lhs
index b20d32e..7410092 100644
--- a/compiler/typecheck/TcType.lhs
+++ b/compiler/typecheck/TcType.lhs
@@ -30,7 +30,7 @@ module TcType (
   isImmutableTyVar, isSkolemTyVar, isMetaTyVar,  isMetaTyVarTy,
   isSigTyVar, isExistentialTyVar,  isTyConableTyVar,
   metaTvRef, 
-  isFlexi, isIndirect, isRuntimeUnk, isUnk,
+  isFlexi, isIndirect, isUnkSkol, isRuntimeUnkSkol,
 
   --------------------------------
   -- Builders
@@ -123,7 +123,8 @@ module TcType (
   -- Type substitutions
   TvSubst(..), 	-- Representation visible to a few friends
   TvSubstEnv, emptyTvSubst, substEqSpec,
-  mkOpenTvSubst, zipOpenTvSubst, zipTopTvSubst, mkTopTvSubst, notElemTvSubst,
+  mkOpenTvSubst, zipOpenTvSubst, zipTopTvSubst, 
+  mkTopTvSubst, notElemTvSubst, unionTvSubst,
   getTvSubstEnv, setTvSubstEnv, getTvInScope, extendTvInScope, lookupTyVar,
   extendTvSubst, extendTvSubstList, isInScope, mkTvSubst, zipTyEnv,
   substTy, substTys, substTyWith, substTheta, substTyVar, substTyVars, substTyVarBndr,
@@ -334,6 +335,7 @@ data SkolemInfo
 
   | RuleSkol RuleName	-- The LHS of a RULE
   | GenSkol TcType	-- Bound when doing a subsumption check for ty
+
   | RuntimeUnkSkol      -- a type variable used to represent an unknown
                         -- runtime type (used in the GHCi debugger)
 
@@ -669,15 +671,21 @@ isFlexi _     = False
 isIndirect (Indirect _) = True
 isIndirect _            = False
 
-isRuntimeUnk :: TyVar -> Bool
-isRuntimeUnk x | isTcTyVar x
-               , SkolemTv RuntimeUnkSkol <- tcTyVarDetails x = True
-               | otherwise = False
-
-isUnk :: TyVar -> Bool
-isUnk x | isTcTyVar x
-        , SkolemTv UnkSkol <- tcTyVarDetails x = True
-        | otherwise = False
+isRuntimeUnkSkol :: TyVar -> Bool
+-- Called only in TcErrors; see Note [Runtime skolems] there
+isRuntimeUnkSkol x 
+  | isTcTyVar x
+  , SkolemTv info <- tcTyVarDetails x 
+  = case info of 
+       UnkSkol -> True
+       RuntimeUnkSkol -> True
+       _ -> False
+  | otherwise = False
+
+isUnkSkol :: TyVar -> Bool
+isUnkSkol x | isTcTyVar x
+            , SkolemTv UnkSkol <- tcTyVarDetails x = True
+            | otherwise = False
 \end{code}