PEP 749: classmethod and staticmethod do not implement annotation wrapper semantics

Feature

PEP 749 specifies writable __annotate__ and __annotations__ attributes for classmethod and staticmethod. Reading should retrieve and cache the wrapped callable's value in the wrapper's __dict__; writing should update only the wrapper, not the wrapped callable.

Minimal reproduction:

def f() -> Missing:
    pass

for wrapper in (classmethod(f), staticmethod(f)):
    Missing = int
    print(type(wrapper).__name__, wrapper.__annotations__)
    print("__annotations__" in wrapper.__dict__)

    wrapper.__annotations__ = {"x": str}
    print("wrapper:", wrapper.__annotations__)
    print("wrapped:", f.__annotations__)

CPython 3.14.6 caches __annotations__ in each wrapper and leaves f.__annotations__ unchanged after assignment.

RustPython does not cache the delegated value in the wrapper for the unresolved-name case, and assignment mutates the wrapped function's annotations. This is already represented by the expectedFailure marker on ClassPropertiesAndMethods.test_classmethod_staticmethod_annotations in Lib/test/test_descr.py.

Python Documentation or reference to CPython source code

• PEP 749, “Wrappers that provide __annotations__”: https://peps.python.org/pep-0749/#wrappers-that-provide-annotations
• CPython regression test: https://github.com/python/cpython/blob/3.14/Lib/test/test_descr.py