fix super call in list comprehension

[r04922101]

python doc super()

The zero argument form only works inside a class definition, as the compiler fills in the necessary details to correctly retrieve the class being defined, as well as accessing the current instance for ordinary methods.

List comprehension works in a separate scope, where doesn't have class information. Zero argument super call doesn't work in such a scope.

• fixes Flask 3.0.1 breaks path-separated command line arguments #5391

Checklist:

• Add tests that demonstrate the correct behavior of the change. Tests should fail without the change.
• Add or update relevant docs, in the docs folder and in code.
• Add an entry in CHANGES.rst summarizing the change and linking to the issue.
• Add .. versionchanged:: entries in any relevant code docs.
• Run pre-commit hooks and fix any issues.
• Run pytest and tox, no tests failed.

[davidism]

Ah, this was because in Python 3.12, list comprehensions no longer execute in a separate hidden function scope. So no-arg super() became valid, which is what I saw when cleaning up things locally, but still didn't work on older Python versions.

Thanks for adding a test, that's why it wasn't caught last time.

I've reverted the change that caused this, with a further note not to modify it until 3.12 is the minimum supported version.