Pytype

New features and updates:
* Stop supporting target Python 2.
* Enable constant folding, a performance optimization that significantly speeds
up analysis of large data structure literals.

Bug fixes:
* Replace ParamSpec.{args,kwargs} with Any.

New features and updates:
* This is the last release of pytype that supports analyzing code in Python 2.7.
From the next release onward, pytype will only support Python 3.5+.
* Add a typing FAQ.
* Add a pytype_extensions.Dataclass protocol for matching any dataclass.

Bug fixes:
* Use [invalid-annotation] rather than [not-supported-yet] to report stray
TypeVars in variable annotations.
* Fix bugs in attribute matching for Protocol.
* Fix a bug in pytype's import resolution for relative imports.

New features and updates:
* Add more detailed [name-error] messages for UnboundLocalError and the like.
* Remove --check-parameter-types. Its behavior has been the default since
version 2021.07.19.
* Support generic namedtuples.
* Fix bugs and add features for --use-enum-overlay.
* Add a flag, --enforce-noniterable-strings, that forbids implicit iteration
over strings.
* Add support for attr converters.

Bug fixes:
* Get rid of a spurious 'appear only once in signature' TypeVar error.
* Fix a few protocol matching bugs.
* Fix exception handling bugs by tracking the frame state within
try/except/finally blocks.

New features and updates:
* Add a flag, --use-enum-overlay, for greatly improved support for the stdlib
enum library. The behavior of this flag will be enabled by default once it is
stable.
* Default --check-parameter-types to True.
* Take advantage of submodule version information in typeshed/stdlib/VERSIONS.
* typing.Protocol: support non-method attributes and modules, make error
messages more detailed, and fix several bugs.
* Remove --create-pyi-dataclasses and make its behavior the default.
* Do not try doing dead block elimination within try/except blocks.

Bug fixes:
* Handle unions correctly when dealing with exception types.
* Support adding typing.Mapping as a chex.dataclass base class.
* Get rid of some incorrect 'appears only once in signature' TypeVar errors.
* Fix a pyi error caused by _PropertyToConstant not recognizing imported
TypeVars.
* Allow more cases of valid typevars in variable annotations, typing.cast, and
attr.ib's 'type' argument.
* Allow bound class methods to match object.
* Allow bytearray.__contains__ to accept bytes.

New features and updates:
* Open source pytype_extensions, a library of type system extensions for use
with pytype.
* Add an assert_type statement to assert pytype's view of an expression type.
* Remove the [key-error] error class: it found few real type errors and produced
many false positives.

Bug fixes:
* Fix a bug that caused 'self' to be typed as 'Any' in property bodies
(temporarily requires --bind-properties flag).
* Add support for multiple and chained assignments in pyi files.
* Support the 'Protocol[T, ...]' shorthand for generic protocols.
* Typeshed: support py2-only third-party packages with no top-level stubs.

New features and updates:
* Add support for referencing class-scoped TypeVars in variable annotations.
* Add support for generic dataclasses and attrs.

Bug fixes:
* Fix a performance regression in pytype/pytd/typeshed.py.
* Generate mutations from __init__ parameter annotations in stubs.
* Use the typeshed stub for the array module instead of a custom one.