`warnings` is both a lint check and lint group

[sanmai-NL]

It appears impossible to deny all warnings and then warn for specific warning lint checks using rustc CLI parameters. One clear inconsistency that could be connected to this issue is that warnings is both a ‘lint check’ and a ‘lint group’.

rustc -W help

Lint checks provided by rustc:


                                         name  default  meaning
                                         ----  -------  -------
...
                                     warnings  warn     mass-change the level for lints which produce warnings
...
Lint groups provided by rustc:

                   name  sub-lints
                   ----  ---------
               warnings  all built-in lints

Meta

rustc 1.22.0-nightly (185cc5f26 2017-10-02)

[zackmdavis]

Duplicate of #41941. The relevant code is in librustc/lint/levels.rs.

[RalfJung]

Closing as duplicate.