Auto merge of #58081 - Centril:liballoc-2018, r=oli-obk

Transition liballoc to Rust 2018

This transitions liballoc to Rust 2018 edition and applies relevant idiom lints.
I also did a small bit of drive-by cleanup along the way.

r? @oli-obk

I started with liballoc since it seemed easiest. In particular, adding `edition = "2018"` to libcore gave me way too many errors due to stdsimd. Ideally we should be able to continue this crate-by-crate until all crates use 2018.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/liballoc/lib.rs b/src/liballoc/lib.rs
index bd2d8461bf6..80097a128a5 100644
--- a/src/liballoc/lib.rs
+++ b/src/liballoc/lib.rs
@@ -63,6 +63,9 @@
 #![no_std]
 #![needs_allocator]
 
+#![deny(rust_2018_idioms)]
+#![allow(explicit_outlives_requirements)]
+
 #![warn(deprecated_in_future)]
 #![warn(intra_doc_link_resolution_failure)]
 #![warn(missing_debug_implementations)]
@@ -121,8 +124,6 @@
 extern crate std;
 #[cfg(test)]
 extern crate test;
-#[cfg(test)]
-extern crate rand;
 
 // Module with internal macros used by other modules (needs to be included before other modules).
 #[macro_use]
@@ -164,5 +165,5 @@ pub mod vec;
 
 #[cfg(not(test))]
 mod std {
-    pub use core::ops;      // RangeFull
+    pub use core::ops; // RangeFull
 }