In the worst case, new lints are only available in nightly for 2 weeks, before
hitting beta and ultimately stable. This and the fact that fewer people use
nightly Rust nowadays makes it more probable that a lint with many FPs hits
stable. This leads to annoyed users, that will disable these new lints in the
best case and to more annoyed users, that will stop using Clippy in the worst.
A process should be developed and implemented to prevent this from happening.

#6429

Steps to completion:

• Implement crater aka cargo dev-lintcheck for Clippy (add "cargo dev crater" to run clippy on a fixed set of crates and diff the lint warnings #6469)
• Implement framework so that lints can be enabled in nightly only
  • Previous attempt to implement this in Clippy Implement framework so that lints can be enabled in nightly only #8211
• Define clear process for stabilizing lints
  • We now have a FCP process where 2 team members have to approve on a new lint and no other team member vetos it.
• CFP: Ask people using Clippy to submit their crates, so we can check new lints on them before releasing the lints to stable
  • We test ~200 crates on CI, so that wouldn't help much more.
• Make it easy to run the crater tool on peoples private code / CI to get even more input
  • Lintcheck is now run on CI