Support dict as parameter for `choices`

[Tenzer]

The Django documentation shows that you can provide a dict as input to the choices parameter on the CharField type: https://docs.djangoproject.com/en/6.0/ref/models/fields/#choices. It is, however, not accepted by the type annotations here.

Example file:

from django.db import models


class Foo(models.Model):
    STATUSES = {
        "new": "New",
        "open": "Open",
        "closed": "Closed",
        "archived": "Archived",
    }

    status = models.CharField(choices=STATUSES)

Output from mypy:

models.py:12: error: Argument "choices" to "CharField" has incompatible type "dict[str, str]"; expected "Iterable[tuple[Never, str] | tuple[str, Iterable[tuple[Never, str]]]] | type[TextChoices]"  [arg-type]

Output from Pyright:

models.py
  models.py:12:39 - error: Argument of type "dict[str, str]" cannot be assigned to parameter "choices" of type "Iterable[tuple[_C@CharField, str] | tuple[str, Iterable[tuple[_C@CharField, str]]]] | type[TextChoices]" in function "__new__"
    Type "dict[str, str]" is not assignable to type "Iterable[tuple[_C@CharField, str] | tuple[str, Iterable[tuple[_C@CharField, str]]]] | type[TextChoices]"
      "dict[str, str]" is not assignable to "Iterable[tuple[_C@CharField, str] | tuple[str, Iterable[tuple[_C@CharField, str]]]]"
        Type parameter "_T_co@Iterable" is covariant, but "str" is not a subtype of "tuple[_C@CharField, str] | tuple[str, Iterable[tuple[_C@CharField, str]]]"
          Type "str" is not assignable to type "tuple[_C@CharField, str] | tuple[str, Iterable[tuple[_C@CharField, str]]]"
            "str" is not assignable to "tuple[_C@CharField, str]"
            "str" is not assignable to "tuple[str, Iterable[tuple[_C@CharField, str]]]"
      Type "dict[str, str]" is not assignable to type "type[TextChoices]" (reportArgumentType)
1 error, 0 warnings, 0 informations

Ouput from ty:

error[[invalid-argument-type](https://ty.dev/rules#invalid-argument-type)]: Argument to constructor `CharField.__new__` is incorrect
  --> models.py:12:31
   |
12 |     status = models.CharField(choices=STATUSES)
   |                               ^^^^^^^^^^^^^^^^ Expected `Iterable[tuple[Unknown, str] | tuple[str, Iterable[tuple[Unknown, str]]]]`, found `dict[str, str]`
   |
info: type `dict[str, str]` is not assignable to protocol `Iterable[tuple[Unknown, str] | tuple[str, Iterable[tuple[Unknown, str]]]]`
info: └── protocol member `__iter__` is incompatible
info:     └── incompatible return types: `Iterator[str]` is not assignable to `Iterator[tuple[Unknown, str] | tuple[str, Iterable[tuple[Unknown, str]]]]`
info:         └── protocol `Iterator[str]` is not assignable to protocol `Iterator[tuple[Unknown, str] | tuple[str, Iterable[tuple[Unknown, str]]]]`
info:             └── protocol member `__next__` is incompatible
info:                 └── incompatible return types: `str` is not assignable to `tuple[Unknown, str] | tuple[str, Iterable[tuple[Unknown, str]]]`
info: Matching overload defined here
   --> venv/lib/python3.14/site-packages/django-stubs/db/models/fields/__init__.pyi:702:9
    |
702 |       def __new__(
    |           ^^^^^^^
    |
   ::: venv/lib/python3.14/site-packages/django-stubs/db/models/fields/__init__.pyi:722:9
    |
722 | /         choices: Iterable[tuple[_C, str] | tuple[str, Iterable[tuple[_C, str]]]]
723 | |         | type[TextChoices] = ...,
    | |_________________________________- Parameter declared here
    |
info: Non-matching overloads for function `__new__`:
info:   (cls, verbose_name: str | None = ..., *, name: str | None = ..., primary_key: bool = ..., max_length: int = ..., db_collation: str | None = ..., unique: bool = ..., blank: bool = ..., null: Literal[True], db_index: bool = ..., default: _C@CharField | (() -> _C@CharField) = ..., db_default: _C@CharField | Func = ..., editable: bool = ..., auto_created: bool = ..., serialize: bool = ..., unique_for_date: str | None = ..., unique_for_month: str | None = ..., unique_for_year: str | None = ..., choices: Iterable[tuple[_C@CharField, str] | tuple[str, Iterable[tuple[_C@CharField, str]]]] = ..., help_text: str = ..., db_column: str | None = ..., db_comment: str | None = ..., db_tablespace: str | None = ..., validators: Iterable[(...) -> None] = ..., error_messages: dict[str, Any] | None = ...) -> CharField[str | None]

Found 1 diagnostic

Tested with these versions:

Package           Version
----------------- ---------------
Django            6.0.7
django-types      0.24.0
mypy              2.2.0
pyright           1.1.411
ty                0.0.57

I can see there's already a type defined that allows for a dict to be passed to the choices parameter:

django-types/django-stubs/db/models/fields/__init__.pyi

Line 23 in 36159bf

_FieldChoices: TypeAlias = _LiteralFieldChoices | Callable[[], _LiteralFieldChoices]

It is, however, not used where the type checkers need it:

django-types/django-stubs/db/models/fields/__init__.pyi

Lines 730 to 731 in 36159bf

	choices: Iterable[tuple[_C, _StrOrPromise] | tuple[str, Iterable[tuple[_C, _StrOrPromise]]]]
	| type[TextChoices] = ...,

At first glance, it looks like it would be enough to change the latter lines to choices: _FieldChoices = ..., but I wonder if there's something deeper at play here which doesn't make it as straight forward?