Use implication constraints to improve type inference

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

diff --git a/compiler/typecheck/TcRules.lhs b/compiler/typecheck/TcRules.lhs
index ef8e388..0a2babe 100644 (file)
--- a/compiler/typecheck/TcRules.lhs
+++ b/compiler/typecheck/TcRules.lhs
@@ -78,7 +78,8 @@ tcRule (HsRule name act vars lhs fv_lhs rhs fv_rhs)
        --
        -- NB: tcSimplifyInferCheck zonks the forall_tvs, and 
        --     knocks out any that are constrained by the environment
-    tcSimplifyInferCheck (text "tcRule")
+    getInstLoc (SigOrigin (RuleSkol name))     `thenM` \ loc -> 
+    tcSimplifyInferCheck loc
                         forall_tvs
                         lhs_dicts rhs_lie      `thenM` \ (forall_tvs1, rhs_binds) ->
     mappM zonkQuantifiedTyVar forall_tvs1      `thenM` \ forall_tvs2 ->
@@ -100,7 +101,7 @@ tcRuleBndrs (RuleBndrSig var rn_ty : vars) thing_inside
 --  e.g        x :: a->a
 --  The tyvar 'a' is brought into scope first, just as if you'd written
 --             a::*, x :: a->a
-  = do { let ctxt = RuleSigCtxt (unLoc var)
+  = do { let ctxt = FunSigCtxt (unLoc var)
        ; (tyvars, ty) <- tcHsPatSigType ctxt rn_ty
        ; let skol_tvs = tcSkolSigTyVars (SigSkol ctxt) tyvars
              id_ty = substTyWith tyvars (mkTyVarTys skol_tvs) ty