Goal:
  
  b : Byte.byte
  xs : t
  ys : t
  IHxs : forall ys : t,
         eqb xs ys = match compare xs ys with
                     | Eq => true
                     | _ => false
                     end
  ============================
   (eqb (String b xs) ys =
    match compare (String b xs) ys with
    | Eq => true
    | _ => false
    end)


DEBUG:Going to execute:
<coq-core.plugins.ssreflect::ssrtclintros@0> arg