Changelog
### 1.10
```
We’ve just uploaded mypy 1.10 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)). 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](http://mypy.readthedocs.io).
Support TypeIs (PEP 742)
Mypy now supports `TypeIs` ([PEP 742](https://peps.python.org/pep-0742/)), 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:
python
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](https://github.com/python/mypy/pull/16898)).
Support TypeVar Defaults (PEP 696)
[PEP 696](https://peps.python.org/pep-0696/) adds support for type parameter defaults.
Example:
python
from typing import Generic
from typing_extensions import TypeVar
T = TypeVar("T", default=int)
class C(Generic[T]):
...
x: C = ...
y: C[str] = ...
reveal_type(x) C[int], because of the default
reveal_type(y) C[str]
TypeVar defaults will be added to the `typing` module in Python 3.13, but they
can be used with earlier Python releases by importing `TypeVar` from
`typing_extensions`.
This feature was contributed by Marc Mueller (PR [16878](https://github.com/python/mypy/pull/16878)
and PR [16925](https://github.com/python/mypy/pull/16925)).
Support TypeAliasType (PEP 695)
As part of the initial steps towards implementing [PEP 695](https://peps.python.org/pep-0695/), mypy now supports `TypeAliasType`.
`TypeAliasType` provides a backport of the new `type` statement in Python 3.12.
python
type ListOrSet[T] = list[T] | set[T]
is equivalent to:
python
T = TypeVar("T")
ListOrSet = TypeAliasType("ListOrSet", list[T] | set[T], type_params=(T,))
Example of use in mypy:
python
from typing_extensions import TypeAliasType, TypeVar
NewUnionType = TypeAliasType("NewUnionType", int | str)
x: NewUnionType = 42
y: NewUnionType = 'a'
z: NewUnionType = object() error: Incompatible types in assignment (expression has type "object", variable has type "int | str") [assignment]
T = TypeVar("T")
ListOrSet = TypeAliasType("ListOrSet", list[T] | set[T], type_params=(T,))
a: ListOrSet[int] = [1, 2]
b: ListOrSet[str] = {'a', 'b'}
c: ListOrSet[str] = 'test' error: Incompatible types in assignment (expression has type "str", variable has type "list[str] | set[str]") [assignment]
`TypeAliasType` was added to the `typing` module in Python 3.12, but it can be used with earlier Python releases by importing from `typing_extensions`.
This feature was contributed by Ali Hamdan (PR [16926](https://github.com/python/mypy/pull/16926), PR [17038](https://github.com/python/mypy/pull/17038) and PR [17053](https://github.com/python/mypy/pull/17053))
Detect Additional Unsafe Uses of super()
Mypy will reject unsafe uses of `super()` more consistently, when the target has a
trivial (empty) body. Example:
python
class Proto(Protocol):
def method(self) -> int: ...
class Sub(Proto):
def method(self) -> int:
return super().meth() Error (unsafe)
This feature was contributed by Shantanu (PR [16756](https://github.com/python/mypy/pull/16756)).
Stubgen Improvements
- Preserve empty tuple annotation (Ali Hamdan, PR [16907](https://github.com/python/mypy/pull/16907))
- Add support for PEP 570 positional-only parameters (Ali Hamdan, PR [16904](https://github.com/python/mypy/pull/16904))
- Replace obsolete typing aliases with builtin containers (Ali Hamdan, PR [16780](https://github.com/python/mypy/pull/16780))
- Fix generated dataclass `__init__` signature (Ali Hamdan, PR [16906](https://github.com/python/mypy/pull/16906))
Mypyc Improvements
- Provide an easier way to define IR-to-IR transforms (Jukka Lehtosalo, PR [16998](https://github.com/python/mypy/pull/16998))
- Implement lowering pass and add primitives for int (in)equality (Jukka Lehtosalo, PR [17027](https://github.com/python/mypy/pull/17027))
- Implement lowering for remaining tagged integer comparisons (Jukka Lehtosalo, PR [17040](https://github.com/python/mypy/pull/17040))
- Optimize away some bool/bit registers (Jukka Lehtosalo, PR [17022](https://github.com/python/mypy/pull/17022))
- Remangle redefined names produced by async with (Richard Si, PR [16408](https://github.com/python/mypy/pull/16408))
- Optimize TYPE_CHECKING to False at Runtime (Srinivas Lade, PR [16263](https://github.com/python/mypy/pull/16263))
- Fix compilation of unreachable comprehensions (Richard Si, PR [15721](https://github.com/python/mypy/pull/15721))
- Don't crash on non-inlinable final local reads (Richard Si, PR [15719](https://github.com/python/mypy/pull/15719))
Documentation Improvements
- Import `TypedDict` from `typing` instead of `typing_extensions` (Riccardo Di Maio, PR [16958](https://github.com/python/mypy/pull/16958))
- Add missing `mutable-override` to section title (James Braza, PR [16886](https://github.com/python/mypy/pull/16886))
Error Reporting Improvements
- Use lower-case generics more consistently in error messages (Jukka Lehtosalo, PR [17035](https://github.com/python/mypy/pull/17035))
Other Notable Changes and Fixes
- Fix incorrect inferred type when accessing descriptor on union type (Matthieu Devlin, PR [16604](https://github.com/python/mypy/pull/16604))
- Fix crash when expanding invalid `Unpack` in a `Callable` alias (Ali Hamdan, PR [17028](https://github.com/python/mypy/pull/17028))
- Fix false positive when string formatting with string enum (roberfi, PR [16555](https://github.com/python/mypy/pull/16555))
- Narrow individual items when matching a tuple to a sequence pattern (Loïc Simon, PR [16905](https://github.com/python/mypy/pull/16905))
- Fix false positive from type variable within TypeGuard or TypeIs (Evgeniy Slobodkin, PR [17071](https://github.com/python/mypy/pull/17071))
- Improve `yield from` inference for unions of generators (Shantanu, PR [16717](https://github.com/python/mypy/pull/16717))
- Fix emulating hash method logic in `attrs` classes (Hashem, PR [17016](https://github.com/python/mypy/pull/17016))
- Add reverted typeshed commit that uses `ParamSpec` for `functools.wraps` (Tamir Duberstein, PR [16942](https://github.com/python/mypy/pull/16942))
- Fix type narrowing for `types.EllipsisType` (Shantanu, PR [17003](https://github.com/python/mypy/pull/17003))
- Fix single item enum match type exhaustion (Oskari Lehto, PR [16966](https://github.com/python/mypy/pull/16966))
- Improve type inference with empty collections (Marc Mueller, PR [16994](https://github.com/python/mypy/pull/16994))
- Fix override checking for decorated property (Shantanu, PR [16856](https://github.com/python/mypy/pull/16856))
- Fix narrowing on match with function subject (Edward Paget, PR [16503](https://github.com/python/mypy/pull/16503))
- Allow `+N` within `Literal[...]` (Spencer Brown, PR [16910](https://github.com/python/mypy/pull/16910))
- Experimental: Support TypedDict within `type[...]` (Marc Mueller, PR [16963](https://github.com/python/mypy/pull/16963))
- Experimtental: Fix issue with TypedDict with optional keys in `type[...]` (Marc Mueller, PR [17068](https://github.com/python/mypy/pull/17068))
Typeshed Updates
Please see [git log](https://github.com/python/typeshed/commits/main?after=7c8e82fe483a40ec4cb0a2505cfdb0f3e7cc81d9+0&branch=main&path=stdlib) for full list of standard library typeshed stub changes.
Acknowledgements
Thanks to all mypy contributors who contributed to this release:
- Alex Waygood
- Ali Hamdan
- Edward Paget
- Evgeniy Slobodkin
- Hashem
- hesam
- Hugo van Kemenade
- Ihor
- James Braza
- Jelle Zijlstra
- jhance
- Jukka Lehtosalo
- Loïc Simon
- Marc Mueller
- Matthieu Devlin
- Michael R. Crusoe
- Nikita Sobolev
- Oskari Lehto
- Riccardo Di Maio
- Richard Si
- roberfi
- Roman Solomatin
- Sam Xifaras
- Shantanu
- Spencer Brown
- Srinivas Lade
- Tamir Duberstein
- youkaichao
I’d also like to thank my employer, Dropbox, for supporting mypy development.
```
Links
- PyPI: https://pypi.org/project/mypy
- Changelog: https://data.safetycli.com/changelogs/mypy/
- Homepage: https://www.mypy-lang.org/
This PR updates mypy from 1.9.0 to 1.10.0.
Changelog
### 1.10 ``` We’ve just uploaded mypy 1.10 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)). 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](http://mypy.readthedocs.io). Support TypeIs (PEP 742) Mypy now supports `TypeIs` ([PEP 742](https://peps.python.org/pep-0742/)), 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: python 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](https://github.com/python/mypy/pull/16898)). Support TypeVar Defaults (PEP 696) [PEP 696](https://peps.python.org/pep-0696/) adds support for type parameter defaults. Example: python from typing import Generic from typing_extensions import TypeVar T = TypeVar("T", default=int) class C(Generic[T]): ... x: C = ... y: C[str] = ... reveal_type(x) C[int], because of the default reveal_type(y) C[str] TypeVar defaults will be added to the `typing` module in Python 3.13, but they can be used with earlier Python releases by importing `TypeVar` from `typing_extensions`. This feature was contributed by Marc Mueller (PR [16878](https://github.com/python/mypy/pull/16878) and PR [16925](https://github.com/python/mypy/pull/16925)). Support TypeAliasType (PEP 695) As part of the initial steps towards implementing [PEP 695](https://peps.python.org/pep-0695/), mypy now supports `TypeAliasType`. `TypeAliasType` provides a backport of the new `type` statement in Python 3.12. python type ListOrSet[T] = list[T] | set[T] is equivalent to: python T = TypeVar("T") ListOrSet = TypeAliasType("ListOrSet", list[T] | set[T], type_params=(T,)) Example of use in mypy: python from typing_extensions import TypeAliasType, TypeVar NewUnionType = TypeAliasType("NewUnionType", int | str) x: NewUnionType = 42 y: NewUnionType = 'a' z: NewUnionType = object() error: Incompatible types in assignment (expression has type "object", variable has type "int | str") [assignment] T = TypeVar("T") ListOrSet = TypeAliasType("ListOrSet", list[T] | set[T], type_params=(T,)) a: ListOrSet[int] = [1, 2] b: ListOrSet[str] = {'a', 'b'} c: ListOrSet[str] = 'test' error: Incompatible types in assignment (expression has type "str", variable has type "list[str] | set[str]") [assignment] `TypeAliasType` was added to the `typing` module in Python 3.12, but it can be used with earlier Python releases by importing from `typing_extensions`. This feature was contributed by Ali Hamdan (PR [16926](https://github.com/python/mypy/pull/16926), PR [17038](https://github.com/python/mypy/pull/17038) and PR [17053](https://github.com/python/mypy/pull/17053)) Detect Additional Unsafe Uses of super() Mypy will reject unsafe uses of `super()` more consistently, when the target has a trivial (empty) body. Example: python class Proto(Protocol): def method(self) -> int: ... class Sub(Proto): def method(self) -> int: return super().meth() Error (unsafe) This feature was contributed by Shantanu (PR [16756](https://github.com/python/mypy/pull/16756)). Stubgen Improvements - Preserve empty tuple annotation (Ali Hamdan, PR [16907](https://github.com/python/mypy/pull/16907)) - Add support for PEP 570 positional-only parameters (Ali Hamdan, PR [16904](https://github.com/python/mypy/pull/16904)) - Replace obsolete typing aliases with builtin containers (Ali Hamdan, PR [16780](https://github.com/python/mypy/pull/16780)) - Fix generated dataclass `__init__` signature (Ali Hamdan, PR [16906](https://github.com/python/mypy/pull/16906)) Mypyc Improvements - Provide an easier way to define IR-to-IR transforms (Jukka Lehtosalo, PR [16998](https://github.com/python/mypy/pull/16998)) - Implement lowering pass and add primitives for int (in)equality (Jukka Lehtosalo, PR [17027](https://github.com/python/mypy/pull/17027)) - Implement lowering for remaining tagged integer comparisons (Jukka Lehtosalo, PR [17040](https://github.com/python/mypy/pull/17040)) - Optimize away some bool/bit registers (Jukka Lehtosalo, PR [17022](https://github.com/python/mypy/pull/17022)) - Remangle redefined names produced by async with (Richard Si, PR [16408](https://github.com/python/mypy/pull/16408)) - Optimize TYPE_CHECKING to False at Runtime (Srinivas Lade, PR [16263](https://github.com/python/mypy/pull/16263)) - Fix compilation of unreachable comprehensions (Richard Si, PR [15721](https://github.com/python/mypy/pull/15721)) - Don't crash on non-inlinable final local reads (Richard Si, PR [15719](https://github.com/python/mypy/pull/15719)) Documentation Improvements - Import `TypedDict` from `typing` instead of `typing_extensions` (Riccardo Di Maio, PR [16958](https://github.com/python/mypy/pull/16958)) - Add missing `mutable-override` to section title (James Braza, PR [16886](https://github.com/python/mypy/pull/16886)) Error Reporting Improvements - Use lower-case generics more consistently in error messages (Jukka Lehtosalo, PR [17035](https://github.com/python/mypy/pull/17035)) Other Notable Changes and Fixes - Fix incorrect inferred type when accessing descriptor on union type (Matthieu Devlin, PR [16604](https://github.com/python/mypy/pull/16604)) - Fix crash when expanding invalid `Unpack` in a `Callable` alias (Ali Hamdan, PR [17028](https://github.com/python/mypy/pull/17028)) - Fix false positive when string formatting with string enum (roberfi, PR [16555](https://github.com/python/mypy/pull/16555)) - Narrow individual items when matching a tuple to a sequence pattern (Loïc Simon, PR [16905](https://github.com/python/mypy/pull/16905)) - Fix false positive from type variable within TypeGuard or TypeIs (Evgeniy Slobodkin, PR [17071](https://github.com/python/mypy/pull/17071)) - Improve `yield from` inference for unions of generators (Shantanu, PR [16717](https://github.com/python/mypy/pull/16717)) - Fix emulating hash method logic in `attrs` classes (Hashem, PR [17016](https://github.com/python/mypy/pull/17016)) - Add reverted typeshed commit that uses `ParamSpec` for `functools.wraps` (Tamir Duberstein, PR [16942](https://github.com/python/mypy/pull/16942)) - Fix type narrowing for `types.EllipsisType` (Shantanu, PR [17003](https://github.com/python/mypy/pull/17003)) - Fix single item enum match type exhaustion (Oskari Lehto, PR [16966](https://github.com/python/mypy/pull/16966)) - Improve type inference with empty collections (Marc Mueller, PR [16994](https://github.com/python/mypy/pull/16994)) - Fix override checking for decorated property (Shantanu, PR [16856](https://github.com/python/mypy/pull/16856)) - Fix narrowing on match with function subject (Edward Paget, PR [16503](https://github.com/python/mypy/pull/16503)) - Allow `+N` within `Literal[...]` (Spencer Brown, PR [16910](https://github.com/python/mypy/pull/16910)) - Experimental: Support TypedDict within `type[...]` (Marc Mueller, PR [16963](https://github.com/python/mypy/pull/16963)) - Experimtental: Fix issue with TypedDict with optional keys in `type[...]` (Marc Mueller, PR [17068](https://github.com/python/mypy/pull/17068)) Typeshed Updates Please see [git log](https://github.com/python/typeshed/commits/main?after=7c8e82fe483a40ec4cb0a2505cfdb0f3e7cc81d9+0&branch=main&path=stdlib) for full list of standard library typeshed stub changes. Acknowledgements Thanks to all mypy contributors who contributed to this release: - Alex Waygood - Ali Hamdan - Edward Paget - Evgeniy Slobodkin - Hashem - hesam - Hugo van Kemenade - Ihor - James Braza - Jelle Zijlstra - jhance - Jukka Lehtosalo - Loïc Simon - Marc Mueller - Matthieu Devlin - Michael R. Crusoe - Nikita Sobolev - Oskari Lehto - Riccardo Di Maio - Richard Si - roberfi - Roman Solomatin - Sam Xifaras - Shantanu - Spencer Brown - Srinivas Lade - Tamir Duberstein - youkaichao I’d also like to thank my employer, Dropbox, for supporting mypy development. ```Links
- PyPI: https://pypi.org/project/mypy - Changelog: https://data.safetycli.com/changelogs/mypy/ - Homepage: https://www.mypy-lang.org/