model field values and Combinable errors?

[wynnw]

I'm getting started with mypy/django-stubs, and have run into this category of problem:

A model with an IntegerField gets used as index into an array - say

class MyModel(models.Model):
    id = models.AuthField(primary_key=True)
    mytype = models.IntegerField(choices=[1,2,3])
    
    
 def mymodel_func(m: MyModel, choices: list[int]) -> int:
    return choices[m]  # error is reported here.

Will get an error like: Invalid index type "int | Combinable" for "list[int]"; expected type "int".

I'd like to not use cast() or temporary typehinted variables to deal with this as I've got far too much code to update. Feels like I must be doing something wrong to not have this use case work. I get the same type of Combinable error with DateTimeField's and using datetime methods off of the field.

I know that it's super hard to reproduce these types of issues with big code bases. I'm curious if anyone has run into this type of problem and if there's an easy pattern to use that doesn't require widespread code changes. I'm using mypy 1.13 and django 4.2 and django-stubs 5.1.1, with the pyproject.toml configuration approach.

[wynnw]

I don't get these Combinable errors when I use mypy==1.7.1 django-stubs==4.2.7 django-stubs-ext==4.2.7

But I definitely don't get some of the nice features of the latest releases. So this must be an issue I should just upgrade django to deal with probably, but I am stuck on LTS releases.