Goal:
    A : Type  P : list A → A → Type
  ============================
   (eq_refl = eq_refl)


DEBUG:Going to execute:
try DepElim.rewrite_sigma2_refl
Level 1: Backtrace:

Rewriting base refl_id does not exist.
Level 1: Backtrace:

Rewriting base refl_id does not exist.