Deprecate two methods of creating typing.TypedDict classes with 0 fields using the functional syntax: `TD = TypedDict("TD")` and `TD = TypedDict("TD", None)`. Both will be disallowed in Python 3.15. To create a TypedDict class with 0 fields, either use `class TD(TypedDict): pass` or `TD = TypedDict("TD", {})`.
Deprecate creating a typing.NamedTuple class using keyword arguments to denote the fields (`NT = NamedTuple("NT", x=int, y=str)`). This will be disallowed in Python 3.15. Use the class-based syntax or the functional syntax instead.
Two methods of creating `NamedTuple` classes with 0 fields using the functional syntax are also deprecated, and will be disallowed in Python 3.15: `NT = NamedTuple("NT")` and `NT = NamedTuple("NT", None)`. To create a `NamedTuple` class with 0 fields, either use `class NT(NamedTuple): pass` or `NT = NamedTuple("NT", [])`.
During the PEP 695 implementation at one point I made
TypeVar.__name__ return garbage, and all of test_typing passed.
So I decided to add a few more tests. In the process I discovered
a minor incompatibility from the C implementation of TypeVar:
empty constraints were returned as None instead of an empty tuple.
This implements PEP 695, Type Parameter Syntax. It adds support for:
- Generic functions (def func[T](): ...)
- Generic classes (class X[T](): ...)
- Type aliases (type X = ...)
- New scoping when the new syntax is used within a class body
- Compiler and interpreter changes to support the new syntax and scoping rules
Co-authored-by: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Co-authored-by: Eric Traut <eric@traut.com>
Co-authored-by: Larry Hastings <larry@hastings.org>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Previously, this used to fail:
```py
from typing import *
T = TypeVar("T")
P = ParamSpec("P")
class X(Generic[P]):
f: Callable[P, int]
Y = X[[int, T]]
Z = Y[str]
```
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
As part of investigation issue https://github.com/python/cpython/issues/102433, I discovered what I believe to be an error where two classes `CI` and `DI` are not being used. The assertions beneath them act on `C` and `D`, duplicating existing assertions in this test.
Automerge-Triggered-By: GH:AlexWaygood
* Fix substitution of TypeVarTuple and ParamSpec together in user generics.
* Fix substitution of ParamSpec followed by TypeVarTuple in generic aliases.
* Check the number of arguments in substitution in user generics containing a
TypeVarTuple and one or more TypeVar.
Fix subscription of type aliases containing bare generic types or types
like TypeVar: for example tuple[A, T][int] and tuple[TypeVar, T][int],
where A is a generic type, and T is a type variable.
Alex Waygood