| NCic.Implicit `Hole -> idref (Ast.UserInput)
| NCic.Implicit _ -> idref (Ast.Implicit)
| NCic.Prod (n,s,t) ->
+ let n = if n.[0] = '_' then "_" else n in
let binder_kind = `Forall in
idref (Ast.Binder (binder_kind, (Ast.Ident (n,None), Some (k ctx s)),
k ((n,NCic.Decl s)::ctx) t))