let subst = List.filter (fun (j,_) -> j <> i) subst in
metasenv, ((i, (name, ctx, term, ty)) :: subst)
with Not_found -> assert false))
| NCic.Meta (n, _), _ when is_locked n subst && swap ->
let subst = List.filter (fun (j,_) -> j <> i) subst in
metasenv, ((i, (name, ctx, term, ty)) :: subst)
with Not_found -> assert false))
| NCic.Meta (n, _), _ when is_locked n subst && swap ->