Importing functions from a static class would equally require to have all functions in the same file. I was proposing an alternative to that, not "symbol to file" autoloading.
Though, I know that problem well, sadly. I've suggested PHP should just deprecate the fallback to root namespace, and remove the feature altogether in PHP8. Imho it's the only way to actually solve this. Some say it would be a huge BC break, but in reality old applications could maintain compatibility only by adding a simple autoloader that would alias the global function/constant into the calling namespace. Roave wrote this https://github.com/Roave/FunctionFQNReplacer , PHPStorm is supporting the no-fallback referencing: https://youtrack.jetbrains.com/issue/WI-27425 (recently implemented) https://youtrack.jetbrains.com/issue/WI-34446 (recently implemented) https://youtrack.jetbrains.com/issue/WI-34858 So... it could be the right time to deprecate the fallback to root namespace, before PHP8 gets too close.
