unused_extern_crates lint trigged after return of extern crate syntax for non-Cargo crates (alloc, etc.) #54381
Description
Fallout from #54116, which fixed the syntax for imports from extern crates, a temporary solution to #53166.
This code:
extern crate alloc;Leads to an unused_extern_crates lint failure.
error: `extern crate` is not idiomatic in the new edition --> bla/src/lib.rs:31:1 | 31 | extern crate alloc; | ^^^^^^^^^^^^^^^^^^^ help: convert it to a `use` | note: lint level defined here --> bla/src/lib.rs:15:5 | 15 | unused, | ^^^^^^ = note: #[deny(unused_extern_crates)] implied by #[deny(unused)] Meta
rustc 1.30.0-nightly (20dc0c507 2018-09-19)