Sourced from mypy's changelog.

Mypy Release Notes

Next release

Mypy 1.12

We’ve just uploaded mypy 1.12 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 Python 3.12 Syntax for Generics (PEP 695)

Support for the new type parameter syntax introduced in Python 3.12 is now enabled by default, documented, and no longer experimental. It was available through a feature flag in mypy 1.11 as an experimental feature.

This example demonstrates the new syntax:

# Generic function
def f[T](https://github.com/python/mypy/blob/master/x: T) -> T: ...
reveal_type(f(1))  # Revealed type is 'int'
Generic class
class C[T]:
def init(self, x: T) -> None:
self.x = x
c = C('a')
reveal_type(c.x)  # Revealed type is 'str'
Type alias
type A[T] = C[list[T]]

For more information, refer to the documentation.

These improvements are included:

• Document Python 3.12 type parameter syntax (Jukka Lehtosalo, PR 17816)
• Further documentation updates (Jukka Lehtosalo, PR 17826)
• Allow Self return types with contravariance (Jukka Lehtosalo, PR 17786)
• Enable new type parameter syntax by default (Jukka Lehtosalo, PR 17798)
• Generate error if new-style type alias used as base class (Jukka Lehtosalo, PR 17789)
• Inherit variance if base class has explicit variance (Jukka Lehtosalo, PR 17787)

... (truncated)

• f2a39b1 Update version to 1.12.0
• b4ec37a Add one more 1.12 changelog item (#17936)
• cc1c679 Better handling of generic functions in partial plugin (#17925)
• d65a013 Add latest 1.12 changes to changelog (#17921)
• 2e38965 Fix union callees with functools.partial (#17903)
• c5d3673 Document ReadOnly (PEP 705) (#17905)
• 964a7a5 Make ReadOnly TypedDict items covariant (#17904)
• 24bfb34 Include CHANGELOG.md in sdists (#17882)
• 21d46ed documentation for TypeIs (#17821)
• c692943 Improvements to functools.partial of types (#17898)
• Additional commits viewable in compare view

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