[andrepd]

But false is the correct result for those cases. Addition is addition and overflow is undefined (= can assume that doesn't happen), it's not addition modulo 2^n.

[Joker_vD]

We are not talking about C here. Imagine it was e.g. Java, or C#, or Rust in release mode, or heck, even Lean itself but with fixed-precision integers.

[alternatex]

Overflow/underflow does happen in C# though. You have to manually opt-out by using a `checked` block anywhere you do arithmetic.