`dict[str, str]` is not assignable to TypedDict key... [bad-typed-dict-key]

[lolpack]

Pyrefly infers that a dict is a typed dict and gives a confusing error as result. The root cause of this error is that we do not union an unknown value in a dict. pyright, mypy and ty all widen the value to include the union of unknown/Any whereas Pyrefly does not.

At a minimum this error should be a bad assignment or argument error like pyright mypy ty. But we probably should just allow the union and put the stricter behavior behind a flag.

https://pyrefly.org/sandbox/?project=N4IgZglgNgpgziAXKOBDAdgEwEYHsAeAdAA4CeS4ATrgLYAEArugNbq4Du6dENxulAFzoBVFm04AddFJrw0Acxh0AvHWBS6muhJCYYANwgBjGAH0ImHYm26DxmAFoLOgDQatOvYZOmATFZExDml0AF8pKUoDGFQoUwFSYhgAClk4BRgASgj0NIyAbR1UAQFUIwALWXQBHQBdFTUdHlRFAJ0BcoYabAcGSigdcPQQFxAyKLAoUkIBWigKAGI6AAVSCam6NCw8fDojXHRIeT7iiAPCKSWAZRglcpLiOEQAemfxmEnp-nlnmHRnzC4IxwZ77Q4QY6UU4HZ50MD8OiofSoaCobCwPYHI4nARnLi4Yi4g5wC7oMgdA4OfQwShwPENHQAZkIAEZ-CApBBDjSHOwIB0HJBaQJenAYMowLExVJ8jTqLTalImDw%2BIIYJgHJgIFEjLjqQ0AOQQthRA1SNgiqIARwY2vVDmYMFIDjKJnShvYqEo6DNw1CozKepgADFoDAKFscAQSORQkA