Goal:
    A : Type  HA : ReflectEq A  x : option A  y : option A
  ============================
   (reflectProp (x = y) (eq_option eqb x y))


DEBUG:Going to execute:
subst *
Level 0: Backtrace:

Failed to progress.
Level 1: Backtrace:

Failed to progress.
Level 0: Backtrace:

Failed to progress.
Level 0: Backtrace:

Failed to progress.