- -> ConDecl RdrName
-mkGadtDecl name (L _ (HsForAllTy _ qvars cxt ty)) = mk_gadt_con name qvars cxt ty
-mkGadtDecl name ty = mk_gadt_con name [] (noLoc []) ty
+ -> [ConDecl RdrName]
+-- We allow C,D :: ty
+-- and expand it as if it had been
+-- C :: ty; D :: ty
+-- (Just like type signatures in general.)
+mkGadtDecl names ty
+ = [mk_gadt_con name qvars cxt tau | name <- names]
+ where
+ (qvars,cxt,tau) = case ty of
+ L _ (HsForAllTy _ qvars cxt tau) -> (qvars, cxt, tau)
+ _ -> ([], noLoc [], ty)