Warning directives aren't respected when in front of methods in impls

[msullivan]

The following code shouldn't have any warnings, but does:

impl extensions for () {
    #[warn(no_while_true)]
    fn bar() { while true { } }
}

fn main() {}

[msullivan]

Oh, argh. This is because methods aren't items, and lint only grabs warning attributes from crates and items. Furthermore, the table holding the lint settings is keyed off of item ids...

[pcwalton]

I don't believe this is backwards incompatible, renominating.

[alexcrichton]

This works as of #6093