Regression resolving enum variant with name of struct when both are imported

[brson]

rotor-http commit 42fc6cc9424bc32b8e2a36798f6f33ac4f065420 does not build on nightly 2fb0c5e with this error:

src/server/response.rs:43:37: 43:41 error: `Head` is the name of a struct or struct variant, but this expression uses it like a function name [E0423]
src/server/response.rs:43             body: if head.method == Head { Ignored } else { Normal },
                                                              ^~~~
src/server/response.rs:43:37: 43:41 help: run `rustc --explain E0423` to see a detailed explanation
src/server/response.rs:43:37: 43:41 help: did you mean to write: `Head { /* fields */ }`?

This worked as of nightly-2015-12-01, commit a2866e3.

Head is both a hyper::message::Message enum variant and a rotor-http struct and both are imported.

cc @rust-lang/lang @tailhook

[aturon]

cc @rust-lang/compiler

[nrc]

cc @petrochenkov

[petrochenkov]

This is due to #30896
The name conflict is legitimate, but it wasn't reported in cross-crate scenarios.
However, I expected this to be broken by #30882, not by #30896 o_O
cc #30882 (comment)

[nikomatsakis]

@petrochenkov to be clear, are you saying this is a bug fix?

[petrochenkov]

@nikomatsakis Yes

[nikomatsakis]

Nominating for compiler team meeting, but I am inclined to flag this in the relnotes and take no action. Seems like it was a bug fix and I'm guessing rotor-http has fixed it downstream by now in any case, and there is no indication of widespread impact.