Definition compare_cont_correct' : ltac:(auto_for_auto compare_cont_correct) := compare_cont_correct.
Hint Resolve compare_cont_correct' : eval.

Lemma compare_correct p: forall q tp tq,
evaluates tp (value_of_pos p) ->
evaluates tq (value_of_pos q) ->
evaluates (compareF (: tp, tq :)) (value_of_comp (Pos.compare p q)).