Sometimes during development I would like to allow warnings. For example, for dead_code. Yet, in CI and pre_commit git hooks, I have RUSTFLAGS="--deny warnings".
So I'm thinking that what I would like is an attribute such as
#[expect(dead_code)]
fn foo() {
todo!();
}
It would work similar to TypesScript's @ts-expect-error and yet be more specific, expecting a specific list of warnings.
Not sure whether it would make sense for expecting errors, as well.
This is supported experimentally. The RFC is called Lint Reasons. The form is exactly what you would expect: #[expect(lint)].
#![feature(lint_reasons)]
#[expect(dead_code)]
fn foo() {
todo!();
}
If the expectation is not fulfilled, a warning is raised. You can #[deny(unfulfilled_lint_expectations)] to make it into an error.
If you only want to allow the warning (but not warn when it is not raised), use #[allow(lint)]:
#[allow(dead_code)]
fn foo() {
todo!();
}