23.10.0

• Introduce Y090, which warns if you have an annotation such as tuple[int] or Tuple[int]. These mean "a tuple of length 1, in which the sole element is of type int". This is sometimes what you want, but more usually you'll want tuple[int, ...], which means "a tuple of arbitrary (possibly 0) length, in which all elements are of type int".

  This error code is disabled by default due to the risk of false-positive errors. To enable it, use the --extend-select=Y090 option.

• Y011 now ignores sentinel and _typeshed.sentinel in default values.