Rename `allow-mixed-uninlined-format-args`

[smoelius]

Description

I humbly suggest that allow-mixed-uninlined-format-args (i.e, the configuration affecting uninlined_format_args) be renamed.

Recall, changing this configuration from true (its default) to false causes Clippy to flag the following code:

format!("{} {}", var, 1+2); // Clippy suggests: format!("{var} {}", 1+2);

I personally find the configuration name confusing and difficult to read. Also, it recently confused Codex. 😬

Transcript

So you think the configuration name is confusing?

Yes. I initially read:

allow-mixed-uninlined-format-args = false

as “mixed positional and captured arguments are forbidden.”

Its actual meaning is closer to: “do not exempt an uninlined variable merely because the same format call also contains an expression that cannot be inlined.”

Thus Clippy accepts—and may produce—the mixed result:

panic!("Could not parse config as `{}`: {error}", type_name::<T>())

Here, error is inlined, while the non-capturable expression remains positional. The configuration name describes when the lint tolerates uninlined arguments, not whether mixed formatting syntax itself is allowed, which makes it easy to misread.

Adding to the above, the fact that the default is true feels odd to me. A default of false feels more natural. Currently, there are 26 configurations that default to false, but only 14 that default to true, which I think supports this view.

Personally, I suggest the configuration be renamed to lint-inlinable-args-in-mixed-format-calls and have the default be false. Modulo the change in name and polarity, everything else about the configuration would stay the same.

I could submit a PR if the maintainers and @nyurik are agreeable to the change.

P.S. @nyurik I love the unlined_format_args lint! 🙏

[nyurik]

thx, and ironically i also got confused by that name... naming is hard. I don't know of the best name, but yours does sound better.

[smoelius]

@nyurik Sorry to bikeshed this, but I asked Codex to suggest some alternative configuration names, and here is what it proposed:

• inline-format-args-where-possible
• lint-partially-inlinable-format-args

I now think I like the last one (lint-partially-inlinable-format-args). Would you be okay with that? Or is there another one you would like to suggest?