David

I vote yes because this solves a real problem for library authors. In my own Result Flow library, the API depends on generic relationships like Result<TSuccess, TFailure> flowing through methods such as map, then, flatMap, match, and unwrap. Today those relationships mostly live in PHPDoc and PHPStan, not as native PHP syntax that the parser, Reflection, and tools can rely on. This RFC would make those types clearer and more useful to the PHP ecosystem, while keeping PHP’s runtime model practical through bound erasure.