1.57 release notes are missing changes to dead code analysis

[nsunderland1]

#85200 landed in 1.57, causing derived Debug and Clone implementations to be ignored during dead code analysis. The release notes for 1.57 don't mention this change anywhere.

There's discussion in the original PR about including it in the release notes, but looks like nobody got around to it.

[nsunderland1]

I think this is also worth a mention in the compatibility notes for 1.57, given that it can break builds where deny(dead_code) is set.

[nsunderland1]

@rustbot label +D-incorrect +D-invalid-suggestion

[nsunderland1]

@rustbot label -D-incorrect -D-invalid-suggestion

[nsunderland1]

My bad there, had two different issues open.

[Mark-Simulacrum]

I'd be happy to approve a PR adding a line to the release notes about this.

[nsunderland1]

@rustbot claim