Goal:
  
  A : Type
  p : A → bool
  x : A
  l : list A
  H : is_true (p x)
  H0 : Forall (λ x : A, p x) l
  IHForall : is_true (forallb p l)
  ============================
   (is_true (true && true))


DEBUG:Going to execute:
done
Level 0: Backtrace:

No matching clauses for match.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 1: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
DEBUG LTAC Evaluated term: H
DEBUG LTAC Evaluated term: H
DEBUG LTAC Evaluated term: IHForall
DEBUG LTAC Evaluated term: IHForall
DEBUG LTAC Evaluated term: Prop
DEBUG LTAC Evaluated term: Prop