Fixed build on newest nightly.

ibabushkin · ibabushkin · commit d104e53ee25a · 2019-09-09T19:26:40.000Z
diff --git a/src/lib.rs b/src/lib.rs
@@ -1,4 +1,3 @@
-#![feature(rustc_diagnostic_macros)]
 #![feature(rustc_private)]
 #![allow(clippy::similar_names)]
 #![allow(clippy::single_match_else)]

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,3 @@`
`1`		`-#![feature(rustc_diagnostic_macros)]`
`2`	`1`	`#![feature(rustc_private)]`
`3`	`2`	`#![allow(clippy::similar_names)]`
`4`	`3`	`#![allow(clippy::single_match_else)]`