Goal:
    A : Type  B : Type  R : nat → A → B → Type  n : nat
  ============================
   (eq_refl = eq_refl)


DEBUG:Going to execute:
simpl; DepElim.hnf_eq; DepElim.rewrite_refl_id
Level 3: Backtrace:

No matching clauses for match.
Level 2: Backtrace:

No matching clauses for match.
Level 1: Backtrace:

No matching clauses for match.
Level 1: Backtrace:

Failed to progress.
Level 1: Backtrace:

Failed to progress.
Level 1: Backtrace:

Failed to progress.