Check usages of empty features

[ShadowJonathan]

What it does

Check for all "empty" features in Cargo.toml (a_feature = []), with no optional dependency name collisions, and try to find if any config attribute in the file has that feature, if it doesn't, raise.

Lint Name

unused_crate_feature

Category

pedantic

Advantage

• Allow libraries to clean up unused features, which could then signal downstream that something has changed.
• Cleaner code and crates, with less "cruft"

Drawbacks

Possible false-positives if cargo were to infer more from features in the future (other than optional dependencies and the likes)

Example

[features]
a_thing = []

This feature is nowhere to be found in any source code, so this raises the warning.

[ShadowJonathan]

#8301 and #1614 are related to this lint