method extend_with_hint env hint =
if not captured && axdef.a_name = hint.h_name then
let better = ref false in
let partials' = List.map
(function
| Svalue _ as s -> s
| Sclosure c ->
let s = apply_sigma env hint.h_sigma c in
(match s with Svalue _ -> better := true | _ -> ()) ; s)
partials in
if !better then Some(new instance axdef partials') else None
else None