∀ {R : Type u_2} {S : Type u_1} [inst : NonAssocSemiring R] [inst_1 : NonAssocSemiring S] (e : R ≃+* S) (x y : R),
  (↑e.toAddEquiv.toAddMonoidHom).toFun (x + y) =
    (↑e.toAddEquiv.toAddMonoidHom).toFun x + (↑e.toAddEquiv.toAddMonoidHom).toFun y