Proof using.
intros.
unfold handleRequestVote in *.
repeat break_match; find_inversion; subst; auto;
simpl in *; apply advanceCurrentTerm_currentTerm.
Qed.

Lemma handleRequestVote_currentTerm_votedFor :
forall pDst t cid lli llt d d' m,
handleRequestVote pDst d t cid lli llt = (d', m) ->
(currentTerm d < currentTerm d' \/
(currentTerm d = currentTerm d' /\ votedFor d = None) \/
(currentTerm d = currentTerm d' /\ votedFor d = votedFor d')).