Unlike the usual operations, these never overflow, preferring instead to raise.
val (+) : Base__Int63.t ‑> Base__Int63.t ‑> Base__Int63.tval (-) : Base__Int63.t ‑> Base__Int63.t ‑> Base__Int63.tval abs : Base__Int63.t ‑> Base__Int63.tval neg : Base__Int63.t ‑> Base__Int63.t