In an AbsBinds, the 'dicts' can include EqInsts

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

diff --git a/compiler/typecheck/TcSimplify.lhs b/compiler/typecheck/TcSimplify.lhs
index f5bdc51..0516308 100644 (file)
--- a/compiler/typecheck/TcSimplify.lhs
+++ b/compiler/typecheck/TcSimplify.lhs
@@ -950,8 +950,10 @@ bindIrredsR loc qtvs co_vars reft givens irreds
   | null irreds
   = return emptyBag
   | otherwise
-  = do { let givens' = filter isDict givens
-               -- The givens can include methods
+  = do { let givens' = filter isAbstractableInst givens
+               -- The givens can (redundantly) include methods
+               -- We want to retain both EqInsts and Dicts
+               -- There should be no implicadtion constraints
                -- See Note [Pruning the givens in an implication constraint]
 
           -- If there are no 'givens' *and* the refinement is empty
@@ -987,7 +989,8 @@ makeImplicationBind :: InstLoc -> [TcTyVar] -> Refinement
 --
 -- This binding must line up the 'rhs' in reduceImplication
 makeImplicationBind loc all_tvs reft
-                   givens      -- Guaranteed all Dicts (TOMDO: true?)
+                   givens      -- Guaranteed all Dicts
+                               -- or EqInsts
                    irreds
  | null irreds                 -- If there are no irreds, we are done
  = return ([], emptyBag)