The first draft of the PEP included support for explicit specialization of generic functions. (It also included support for default type parameter arguments, which is something you have proposed in the past as well.) The feedback I received was that this additional functionality should be moved into other PEPs. This PEP is already relatively complex both in terms of the changes to CPython and the work it will take for type checkers to support. Adding more "bells and whistles" makes it less likely that it will be accepted. If you feel strongly about explicit specialization of generic functions, you could draft another PEP to cover that. I can even provide you with the earlier draft of this PEP if you want to copy and paste the relevant sections. The only complexity is how to handle overloads in this case. -Eric