[vlmutolo]

Rust often has convenience methods in its standard library for things like this that are common and tend to produce bugs when re-implemented over and over, and have a reasonable way to do it without making tradeoffs that will annoy some people over others.

In this case, it’s:

    10i64.checked_add(20i64)
    10i64.checked_mul(20i64)

Both expressions return an Option type, which is effectively a tagged union with type safety on top so you can’t misuse it. You can either call “unwrap” to get the value out and trigger stack unwinding on error, or pattern match on the Option and its inner value in a more functional style.