Allow type families to use GADT syntax (and be GADTs)

[ghc-hetmet.git] / compiler / iface / TcIface.lhs

diff --git a/compiler/iface/TcIface.lhs b/compiler/iface/TcIface.lhs
index d9072f8..42dd3a8 100644 (file)
--- a/compiler/iface/TcIface.lhs
+++ b/compiler/iface/TcIface.lhs
@@ -494,11 +494,15 @@ tcIfaceDataCons tycon_name tycon _ if_cons
        ; arg_tys <- forkM (mk_doc name) (mapM tcIfaceType args)
        ; lbl_names <- mapM lookupIfaceTop field_lbls
 
+       -- Remember, tycon is the representation tycon
+       ; let orig_res_ty = mkFamilyTyConApp tycon 
+                               (substTyVars (mkTopTvSubst eq_spec) univ_tyvars)
+
        ; buildDataCon name is_infix {- Not infix -}
                       stricts lbl_names
                       univ_tyvars ex_tyvars 
                        eq_spec theta 
-                      arg_tys tycon
+                      arg_tys orig_res_ty tycon
        }
     mk_doc con_name = ptext (sLit "Constructor") <+> ppr con_name