; wrapErrTcS $ setCtFlavorLoc fl $
do { -- Apply the current substitition
-- and zonk to get rid of flatten-skolems
- ; ty_binds_bag <- readTcRef ty_binds_var
- ; let subst = mkOpenTvSubst (mkVarEnv (bagToList ty_binds_bag))
+ ; ty_binds_map <- readTcRef ty_binds_var
+ ; let subst = mkOpenTvSubst (mapVarEnv snd ty_binds_map)
; env0 <- tcInitTidyEnv
; (env1, ty1) <- zonkSubstTidy env0 subst ty1
; (env2, ty2) <- zonkSubstTidy env1 subst ty2