Hi Internals, I've recently realized that class constant values cannot always be trusted when late static binding is involved (e.g. static::FOO or $this::FOO), since they can be freely overridden in child classes. That's why the engine knows neither the type and the value before run-time.
Doctrine coding standards has a specific rule which disallows referencing a possibly overridden class constant ( https://github.com/doctrine/coding-standard/blob/8d75920bb04a9be4c73c2a775ee5766262cf2a0d/lib/Doctrine/ruleset.xml#L123 ), but I'm wondering if it would be better to simply make it possible to allow declaring class constants final (thus disallowing overriding) instead? In my opinion, final constants would come with two advantages: - make class constant declarations paranoidly safe - allow the engine to optimize class constants references in LSB context Although I admit that the win is not extra huge, I do think that it would still be useful to have this feature, especially considering that the implementation is very straightforward ( https://github.com/php/php-src/pull/6878). So that's why I'm proposing this as an RFC. Recently, a similar attempt to make class constant declarations safer was the Typed Constants RFC (https://externals.io/message/110755#110755), but unfortunately it has halted since then. I think final and typed constants would be a nice little addition, and would complement each other well. Regards, Máté
