Goal:
  
  A : Type
  P : A → Type
  x : A
  x0 : A
  l : list A
  H : x0 = x ∨ In x l
  p : P x0
  X : All P l
  IHX : In x l → ∥ P x ∥
  ============================
   (locked false = true)


DEBUG:Going to execute:
Ltac.assumption
DEBUG LTAC Evaluated term: not_locked_false_eq_true