Goal:
    A : Type  P : list A → A → Type  x : A  a : All_fold P []  p : P [] x
  ============================
   (let H := CoreTactics.block in let H0 := CoreTactics.block in P [] x)


DEBUG:Going to execute:
DepElim.simplify_IH_hyps
Level 2: Backtrace:

Tactic failure (level 1).
Level 1: Backtrace:

Tactic failure.
Level 0: Backtrace:

Tactic failure.