X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypes%2FType.lhs;h=8ff78fbccfa5f2c082fcb1b7d39b8d1c6e4a13ab;hb=ca9e79e1c70a26b12ea4b63f3a1c5a804462c1a5;hp=09cbdb011d3ee682096dfda7ae6ba7f6d23df57f;hpb=d2ce0f52d42edf32bb9f13796e6ba6edba8bd516;p=ghc-hetmet.git

diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs
index 09cbdb0..8ff78fb 100644
--- a/compiler/types/Type.lhs
+++ b/compiler/types/Type.lhs
@@ -105,7 +105,7 @@ module Type (
 	getTvSubstEnv, setTvSubstEnv, zapTvSubstEnv, getTvInScope, 
         extendTvInScope, extendTvInScopeList,
  	extendTvSubst, extendTvSubstList, isInScope, composeTvSubst, zipTyEnv,
-        isEmptyTvSubst,
+        isEmptyTvSubst, unionTvSubst,
 
 	-- ** Performing substitution on types
 	substTy, substTys, substTyWith, substTysWith, substTheta, 
@@ -829,12 +829,18 @@ isDictTy ty = case splitTyConApp_maybe ty of
 \begin{code}
 tyVarsOfType :: Type -> TyVarSet
 -- ^ NB: for type synonyms tyVarsOfType does /not/ expand the synonym
-tyVarsOfType (TyVarTy tv)		= unitVarSet tv
-tyVarsOfType (TyConApp _ tys)           = tyVarsOfTypes tys
-tyVarsOfType (PredTy sty)		= tyVarsOfPred sty
-tyVarsOfType (FunTy arg res)		= tyVarsOfType arg `unionVarSet` tyVarsOfType res
-tyVarsOfType (AppTy fun arg)		= tyVarsOfType fun `unionVarSet` tyVarsOfType arg
-tyVarsOfType (ForAllTy tyvar ty)	= delVarSet (tyVarsOfType ty) tyvar
+tyVarsOfType (TyVarTy tv)     = unitVarSet tv
+tyVarsOfType (TyConApp _ tys) = tyVarsOfTypes tys
+tyVarsOfType (PredTy sty)     = tyVarsOfPred sty
+tyVarsOfType (FunTy arg res)  = tyVarsOfType arg `unionVarSet` tyVarsOfType res
+tyVarsOfType (AppTy fun arg)  = tyVarsOfType fun `unionVarSet` tyVarsOfType arg
+tyVarsOfType (ForAllTy tv ty) -- The kind of a coercion binder 
+	     	       	      -- can mention type variables!
+  | isTyVar tv		      = inner_tvs `delVarSet` tv
+  | otherwise  {- Coercion -} = -- ASSERT( not (tv `elemVarSet` inner_tvs) )
+                                inner_tvs `unionVarSet` tyVarsOfType (tyVarKind tv)
+  where
+    inner_tvs = tyVarsOfType ty
 
 tyVarsOfTypes :: [Type] -> TyVarSet
 tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys
@@ -1314,6 +1320,13 @@ extendTvSubstList :: TvSubst -> [TyVar] -> [Type] -> TvSubst
 extendTvSubstList (TvSubst in_scope env) tvs tys 
   = TvSubst in_scope (extendVarEnvList env (tvs `zip` tys))
 
+unionTvSubst :: TvSubst -> TvSubst -> TvSubst
+-- Works when the ranges are disjoint
+unionTvSubst (TvSubst in_scope1 env1) (TvSubst in_scope2 env2)
+  = ASSERT( not (env1 `intersectsVarEnv` env2) )
+    TvSubst (in_scope1 `unionInScope` in_scope2)
+            (env1      `plusVarEnv`   env2)
+
 -- mkOpenTvSubst and zipOpenTvSubst generate the in-scope set from
 -- the types given; but it's just a thunk so with a bit of luck
 -- it'll never be evaluated