Sourced from mypy's changelog.

Mypy Release Notes

Next release

Mypy 1.10

We’ve just uploaded mypy 1.10 to the Python Package Index (PyPI). Mypy is a static type checker for Python. This release includes new features, performance improvements and bug fixes. You can install it as follows:

python3 -m pip install -U mypy

You can read the full documentation for this release on Read the Docs.

Support TypeIs (PEP 742)

Mypy now supports TypeIs (PEP 742), which allows functions to narrow the type of a value, similar to isinstance(). Unlike TypeGuard, TypeIs can narrow in both the if and else branches of an if statement:

from typing_extensions import TypeIs
def is_str(s: object) -> TypeIs[str]:
return isinstance(s, str)
def f(o: str | int) -> None:
if is_str(o):
# Type of o is 'str'
...
else:
# Type of o is 'int'
...

TypeIs will be added to the typing module in Python 3.13, but it can be used on earlier Python versions by importing it from typing_extensions.

This feature was contributed by Jelle Zijlstra (PR 16898).

Support TypeVar Defaults (PEP 696)

PEP 696 adds support for type parameter defaults. Example:

from typing import Generic
from typing_extensions import TypeVar
</tr></table>

... (truncated)

• 3faf0fc Remove +dev for version for release 1.10
• a5998d2 Update CHANGELOG.md (#17159)
• 62ea5b0 Various updates to changelog for 1.10 (#17158)
• 2f0864c Update CHANGELOG.md with draft for release 1.10 (#17150)
• e1443bb fix: incorrect returned type of access descriptors on unions of types (#16604)
• 5161ac2 Sync typeshed (#17124)
• e2fc1f2 Fix crash when expanding invalid Unpack in a Callable alias (#17028)
• 3ff6e47 Docs: docstrings in checker.py, ast_helpers.py (#16908)
• 732d98e Fix string formatting for string enums (#16555)
• 8019010 Narrow individual items when matching a tuple to a sequence pattern (#16905)
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