Goal:
  
  A : Type
  f : nat → A → bool
  g : nat → A → bool
  fg : f =2 g
  y : nat
  y0 : list A
  ============================
   (∀ i : nat, f i =1 g i)


DEBUG:Going to execute:
solve
[ trivial
with eq_true
| reflexivity
| symmetry; trivial
| contradiction
| congruence ]