command-line help for -{W,A,D,F} is ambiguous (suggests presence of non-existent 'all' option)

[froydnj]

I downloaded the rust 1.3.0 distribution; rustc -W help says, in part:

Available lint options:
    -W <foo>           Warn about <foo>
    -A <foo>           Allow <foo>
    -D <foo>           Deny <foo>
    -F <foo>           Forbid <foo> (deny, and deny all overrides)

The documentation here for -F suggests to me that -F all would be acceptable (perhaps -W all or -A all too, perhaps). But that doesn't seem to work; rustc says:

error: unknown forbid flag: all
error: aborting due to previous error

Either adding the all group or clarifying the help output around -F would be most welcome. (It's also not immediately clear what the difference between -D and -F is, especially since -D would apparently override the presence of an earlier -F...?)

[pnkfelix]

Would "deny <foo> and all attempts to override" be clearer?

[froydnj]

I think so, yes.

[pnkfelix]

@froydnj in particular, -F is meant to prevent embedded uses of #[allow(..)] or #[warn(..)], which would normally override a -D .. or #[deny(..)]

[froydnj]

Indeed, stating it that way makes it much clearer what's going on. I think I was confused by the use of "deny" in multiple contexts here.

[steveklabnik]

Triage: no change. Seems easy enough, tagging as such.