rustfmt_skip should have the same effect on warnings when inside and outside a module

[8573]

I'm using LALRPOP, which generates a Rust file from a build script,
which file I then reference with a mod <filename> item.

The generated file is large and, relative to the style used by
rustfmt, densely formatted, and has many long lines, at which rustfmt
always emits error messages about being unable to shorten them.
rustfmt does, however, manage to format much of the file — expanding
it from 3010 lines to 8265.

How, if at all, could I instruct rustfmt to ignore this file?

[nrc]

You can add a rustfmt_skip annotation to the mod declaration and then the file will be skipped. See the README for more info on the annotation.

[8573]

Ah! I had put the attribute inside the file (as #![cfg_attr(rustfmt, rustfmt_skip)]), noted that this resulted in more overlong-line messages, saw that that's intentional (#1298), and didn't think that the behavior would be different were I to put the attribute on the mod item; thanks, and my apologies for not trying that earlier.

[solson]

@nrc If #[rustfmt_skip] mod foo; works, then #![rustfmt_skip] at the top-level inside foo.rs should have the same behavior, IMO. It'd be better if a module can be self-contained in that way.

[nikomatsakis]

I agree with @solson on this point -- also, to me, it's just plain surprising for #![foo] in mod.rs and #[foo] mod to have distinct effects.

[topecongiro]

Confirmed that this is supported in 0.3.1-nightly.