Goal:
  
  A : Type
  RA : ReflectEq A
  a : A
  x : list A
  IHx : forall y : list A, reflectProp (x = y) (eqb_list eqb x y)
  ============================
   (a :: x <> [])


DEBUG:Going to execute:
<coq-core.plugins.ltac::discriminate@0>