[3.12] gh-105578: Add more usage examples to `typing.AnyStr` docs (GH-107045) by miss-islington · Pull Request #107503 · python/cpython

Expand Up @@ -849,6 +849,21 @@ using ``[]``. concat(b"foo", b"bar") # OK, output has type 'bytes' concat("foo", b"bar") # Error, cannot mix str and bytes
Note that, despite its name, ``AnyStr`` has nothing to do with the :class:`Any` type, nor does it mean "any string". In particular, ``AnyStr`` and ``str | bytes`` are different from each other and have different use cases::
# Invalid use of AnyStr: # The type variable is used only once in the function signature, # so cannot be "solved" by the type checker def greet_bad(cond: bool) -> AnyStr: return "hi there!" if cond else b"greetings!"
# The better way of annotating this function: def greet_proper(cond: bool) -> str | bytes: return "hi there!" if cond else b"greetings!"
.. data:: LiteralString
Special type that includes only literal strings. Expand Down