Goal:
  
  elt : Type
  eq_elt : elt -> elt -> Prop
  m : t elt
  m' : t elt
  H : forall x y : key, E.eq x y -> find x m = find y m
  H0 : forall x y : key, E.eq x y -> find x m' = find y m'
  H3 : forall (k : key) (e e' : elt),
       find k m = Some e -> find k m' = Some e' -> eq_elt e e'
  k : key
  x : elt
  H1 : find k m = Some x
  H4 : forall k : key,
       (exists e : elt, find k m = Some e) ->
       exists e : elt, find k m' = Some e
  H5 : forall k : key,
       (exists e : elt, find k m' = Some e) ->
       exists e : elt, find k m = Some e
  ============================
   ?T0


DEBUG:Going to execute:
refine v
DEBUG LTAC Evaluated term: ex_intro
DEBUG LTAC Evaluated term: (H5 ?k
                              (ex_intro (fun e : elt => find ?k m' = Some e)
                                 ?e ?Goal10))
Level 6: evaluation returns
H5 ?k (ex_intro (fun e : elt => find ?k m' = Some e) ?e ?Goal10) of type
constr

Level 2: evaluation returns
H5 ?k (ex_intro (fun e : elt => find ?k m' = Some e) ?e ?Goal10) of type
constr

Level 1: evaluation returns
H5 ?k (ex_intro (fun e : elt => find ?k m' = Some e) ?e ?Goal10) of type
constr