Goal:
  
  A : Type
  p : A → bool
  a : A
  l : list A
  IHl : ∀ n : nat, nth_error l n = Some a → forallb p l → p a
  H : p a ∧ forallb p l
  ============================
   (is_true (p a))


DEBUG:Going to execute:
destruct_hyp H
Level 2: Backtrace:

In environment
A : Type
p : A → bool
a : A
l : list A
IHl : ∀ n : nat, nth_error l n = Some a → forallb p l → p a
H : p a ∧ forallb p l
The term "H" has type "p a ∧ forallb p l" while it is expected to have type
 "is_true (p a)".
Level 2: Backtrace:

In environment
A : Type
p : A → bool
a : A
l : list A
IHl : ∀ n : nat, nth_error l n = Some a → forallb p l → p a
H : p a ∧ forallb p l
The term "H" has type "p a ∧ forallb p l" while it is expected to have type
 "is_true (p a)".