Pyflakes

- Fix regression in 2.3.0: type annotations no longer redefine imports

- Recognize tuple concatenation in ``__all__`` export definitions
- Better support use of annotation-only assignments when using
``from __future__ import annotations``
- Recognize special-case typing for ``Annotated``
- Fix undefined name ``__qualname__`` in class scope
- Recognize special-cased typing for ``TypeVar``
- Errors for undefined exports in ``__all__`` are shown in a deterministic order
- Fix false positives in certain typing constructs (``TypeVar``,
``NamedTuple``, ``TypedDict``, ``cast``)

- Include column information in error messages
- Fix ``overload`` detection with other decorators and in non-global scopes
- Fix return-type annotation being a class member
- Fix assignment to ``_`` in doctests with existing ``_`` name
- Namespace attributes which are attached to ast nodes with ``_pyflakes_`` to
avoid conflicts with other libraries (notably bandit)
- Add check for f-strings without placeholders
- Add check for unused/extra/invalid ``'string literal'.format(...)``
- Add check for unused/extra/invalid ``'string literal % ...``
- Improve python shebang detection
- Allow type ignore to be followed by a code `` type: ignore[attr-defined]``
- Add support for assignment expressions (PEP 572)
- Support ``overload`` detection from ``typing_extensions`` as well
- Fix ``overload`` detection for async functions
- Allow ``continue`` inside ``finally`` in python 3.8+
- Fix handling of annotations in positional-only arguments
- Make pyflakes more resistant to future syntax additions
- Fix false positives in partially quoted type annotations
- Warn about ``is`` comparison to tuples
- Fix ``Checker`` usage with async function subtrees
- Add check for ``if`` of non-empty tuple
- Switch from ``optparse`` to ``argparse``
- Fix false positives in partially quoted type annotations in unusual contexts
- Be more cautious when identifying ``Literal`` type expressions

- Fix reported line number for type comment errors
- Fix typing.overload check to only check imported names

- Allow intentional assignment to variables named ``_``
- Recognize ``__module__`` as a valid name in class scope
- ``pyflakes.checker.Checker`` supports checking of partial ``ast`` trees
- Detect assign-before-use for local variables which shadow builtin names
- Detect invalid ``print`` syntax using ``>>`` operator
- Treat ``async for`` the same as a ``for`` loop for introducing variables
- Add detection for list concatenation in ``__all__``
- Exempt ``typing.overload`` from duplicate function declaration
- Importing a submodule of an ``as``-aliased ``import``-import is marked as
used
- Report undefined names from ``__all__`` as possibly coming from a ``*``
import
- Add support for changes in Python 3.8-dev
- Add support for PEP 563 (``from __future__ import annotations``)
- Include Python version and platform information in ``pyflakes --version``
- Recognize ``__annotations__`` as a valid magic global in Python 3.6+
- Mark names used in PEP 484 `` type: ...`` comments as used
- Add check for use of ``is`` operator with ``str``, ``bytes``, and ``int``
literals

- Drop support for EOL Python <2.7 and 3.2-3.3
- Check for unused exception binding in ``except:`` block
- Handle string literal type annotations
- Ignore redefinitions of ``_``, unless originally defined by import
- Support ``__class__`` without ``self`` in Python 3
- Issue an error for ``raise NotImplemented(...)``