Re: [RFC] [Discussion] Bound-Erased Generic Types

On Sun, 10 May 2026 at 21:04, Seifeddine Gmati <azjezz@carthage.software> wrote: > Hello Internals, > > I'd like to start the discussion on a new RFC adding bound-erased > generics types to PHP. > > Generic type parameters can be declared on classes, interfaces, > traits, functions, methods, closures, and arrow functions, with > bounds, defaults, and variance markers. Type parameters erase to their > bound at runtime; the pre-erasure form is preserved for Reflection and > consumed by static analyzers. > > - RFC: https://wiki.php.net/rfc/bound_erased_generic_types > - Implementation: https://github.com/php/php-src/pull/21969 > > Thanks, > Seifeddine. > Hi Seifeddine, Many thanks for such a detailed and interesting proposal. There is one thing that I have not seen specifically addressed in the RFC which is performance. What is the performance cost of this implementation for: a) code that does not use Generics b) code that uses Generics If you could provide some data about this I think it would be a great addition to the RFC Cheers Carlos