Goal:
  
  A : Type
  B : Type
  C : Type
  D : Type
  R : A → B → bool
  f : C → A
  g : D → B
  ============================
   (forallb2 R (map f []) (map g []) =
    forallb2 (λ (x : C) (y : D), R (f x) (g y)) [] [])


DEBUG:Going to execute:
<coq-core.plugins.ltac::trivial@0> $1 $2

Goals:

DEBUG:Going to execute:
hnf

Goals:

DEBUG:Going to execute:
intros

Goals:

DEBUG:Going to execute:
solve
[ do
![ solve
 [ trivial | apply : eq_sym ; trivial ]
 | discriminate
 | contradiction
 | Ltac.split ]
| case not_locked_false_eq_true; Ltac.assumption
| match goal with
  | H:¬ _ |- _ => solve [ case H; trivial ]
  end ]