error: unknown lint: `test_unstable_lint`
   |
   = note: the `test_unstable_lint` lint is unstable
   = help: add `-Zcrate-attr="feature(test_unstable_lint)"` to the command-line options to enable
   = note: requested on the command line with `-D unknown-lints`

error: unknown lint: `test_unstable_lint`
   |
   = note: the `test_unstable_lint` lint is unstable
   = help: add `-Zcrate-attr="feature(test_unstable_lint)"` to the command-line options to enable
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: unknown lint: `test_unstable_lint`
   |
   = note: the `test_unstable_lint` lint is unstable
   = help: add `-Zcrate-attr="feature(test_unstable_lint)"` to the command-line options to enable
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: aborting due to 3 previous errors