Goal:
    A : Type  P : A → Type  Q : A → Type  Hl'1 : list A  Hl' : All Q Hl'1
  ============================
   ([] = Hl'1
    → let H := CoreTactics.block in
      let H0 := CoreTactics.block in All (λ x : A, P x × Q x) [])


DEBUG:Going to execute:
cont id'1 id
Level 2: Backtrace:

Not a one-to-one name mapping
Level 2: Backtrace:

Not a one-to-one name mapping