dead_code lint does not trigger for traits at all.

[oli-cosmian]

I'd expect some kind of warning for a crate defining but not exporting and not using a trait. While it would be great to also report traits that are implemented for types but whose implementation is never used, this may be significantly harder to detect, not sure.

trait Foo {
    fn foo(&self) {}
    fn bar(&self) {}
}

(Playground)

Errors:

   Compiling playground v0.0.1 (/playground)
    Finished dev [unoptimized + debuginfo] target(s) in 1.10s

[oskgo]

Triage: This was fixed at some point. The playground example now gives a dead code warning as it should.