Have any Clippy warnings be added to rustc? Many of them look like real bugs that would benefit more people if included in rustc itself.
Not yet. Adding warnings is tough; some part of the ecosystem compiles with "warnings == errors", and so adding new lints can cause ecosystem breakage.
And not to mention that "soft" warnings not included to the list would essentially have the same problem as `-Wall` vs. `-Weverything`. wink
Crates.io should have a check for things that get published to it that objects if you try to upload something with `#![deny(warnings)]` on the crate. It’s fine for your own code, but production libraries should never use it.