Re: Putting the match expression in constant expressions in PHP 8.0 or 8.1

Hi internals, For unrelated reasons detailed in https://github.com/php/php-src/pull/5951#issuecomment-670969676 , I'm not planning on continuing work on this due to issues I found thinking about the proposal. I initially started work on this because the intended behavior seemed underspecified. "[No objections] from me, though I don't think I'd use it personally." sums up my current stance on that. > Such a construct would be compile-time evaluated, so not having a match should result in a > compile error. Constants in PHP are lazily evaluated under some circumstances, e.g. class constants in constant expressions defer evaluation if they refer to other class constants so that classes aren't unnecessarily autoloaded. https://github.com/php/php-src/pull/5951/files#diff-96ef697f12a482e3f2a7cb0966a6c5beR46 is an example of UnhandledMatchError in function default params, which are also deliberately not permanently cached by C. Compile-time evaluation was something left out of that implementation, but is something that would get added in zend_const_expr_to_zval, like it already is for AST_CONDITIONAL. - Tyson