func `+`(x, y: Int128): Int128 {.inline, ...raises: [], tags: [], forbids: [].}

func `+`(x, y: UInt128): UInt128 {.inline, ...raises: [], tags: [], forbids: [].}

func `+`(x: Int128; y: uint64): Int128 {.inline, ...raises: [], tags: [],
    forbids: [].}

func `+`(x: UInt128; y: uint64): UInt128 {.inline, ...raises: [], tags: [],
    forbids: [].}

func `+=`[T: SomeInt128](x: var T; y: T) {.inline.}

func `+=`[T: SomeInt128](x: var T; y: uint64) {.inline.}

template `+`[T: SomeInt128](x: uint64; y: T): T