SafeMath has custom error messages for sub, div and mod but not add and mul?

@gitpusha asked on Telegram

why is it that the SafeMath lib provides custom error message options for sub div and mod but not for add and mul ?

Hi @gitpusha,

Limited to only those functions which were currently needed, see the discussion in the Pull Request:

Since Solidity v0.8.4 introduced custom errors as a type of entity in the contract ABI, it would be worth it to clarify that this is not what this historical post is referring to.

This post is about custom revert reason strings.