If there is a 2021 edition, what lints should have increased severity, if any?
Looking through the list of lints, a few are already listed as deprecated/being phased out but are allow by default:
- bare-trait-object — introduced in 2018 edition
- elided-lifetime-in-path — introduced in 2018 edition
Similarly, currently warn by default and deprecated/being phased out:
I think this is a good starting point, but there are definitely others (like const-err) that make perfect sense to increase the severity of.