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


DEBUG:Going to execute:
match goal with
           | H:let _ := fixproto in _
             |- _ => red in H; CoreTactics.destruct_calls H; clear H
           end