tree 9e2d00ced92b64c12c7d1bcc3e54d02476dca4b2
parent eba9a4c39211b358437abd05be638f9996d236db
author Michael J. Sullivan <sully@msully.net> 1770086584 -0800
committer Michael J. Sullivan <sully@msully.net> 1770148538 -0800

Implement Unpack of TypeVars for **kwargs inference

Allow `**kwargs: Unpack[K]` where K is a TypeVar bound to TypedDict.
This enables inferring TypedDict types from keyword arguments at call sites.

Example:
    def f[K: BaseTypedDict](**kwargs: Unpack[K]) -> K: ...
    result = f(x=1, y="hello")  # K inferred as TypedDict({'x': int, 'y': str})

Changes:
- semanal.py: Accept TypeVar with TypedDict bound in remove_unpack_kwargs(),
  keep UnpackType for constraint inference
- semanal_typeargs.py: Allow TypeVar with TypedDict bound in visit_unpack_type()
- constraints.py: Generate TypedDict constraints from actual kwargs
- types.py: Handle TypeVar in with_unpacked_kwargs()
- checkexpr.py: Re-expand kwargs after TypeVar inference

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>