(************************************************************************) (* * The Coq Proof Assistant / The Coq Development Team *) (* v * INRIA, CNRS and contributors - Copyright 1999-2018 *) (* nat, f nat = 0). Proof. set (f:= fun _:Set =>0). by exists f. Qed. Goal (exists f: Set -> nat, f nat = 0). Proof. set f := (fun _:Set =>0). by exists f. Qed.