`try!()` macro is generating the `unused_qualifications` lint

[bluss]

The macro should not cause warnings in the user's code. This seems to show up due to other changes.

Seen here: https://internals.rust-lang.org/t/regression-report-stable-2016-10-20-vs-nightly-2016-10-21/4255

The lint is allow by default, but some configurations will enable it.

[bluss]

I don't think adding an allow in try!() is the right fix. Using explicit qualifications is the right thing to do in every macro, and we don't want every user-defined macro to have to add the allow attribute.

@jseyfried Do you know anything about this?

[jseyfried]

I'm not aware of any recent changes that would cause new warnings / regressions, but I could disable the lint for macro-expanded paths easily.

[TimNN]

Introduced between nightly-2016-10-19 and nightly-2016-10-21 (Changes).

@jseyfried: This could probably be a side effect of #37213.

[jseyfried]

@TimNN Indeed, fixed in #37361.

[retep998]

Totally just got bitten by this in winapi, can't wait for the next nightly.