From 779792ff384cd244f480ded0b60e5bf31124133b Mon Sep 17 00:00:00 2001
From: "Felix S. Klock II" <pnkfelix@pnkfx.org>
Date: Tue, 31 Jul 2018 23:00:01 +0200
Subject: [PATCH] address review feedback (`sort_by_key` is so much cleaner
 here than `sort_by`!).

---
 src/librustc_mir/borrow_check/mod.rs | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index 3b767bfdd40e..27221296ff31 100644
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -331,9 +331,7 @@ fn do_mir_borrowck<'a, 'gcx, 'tcx>(
     }
 
     if mbcx.errors_buffer.len() > 0 {
-        mbcx.errors_buffer.sort_by(|diag1, diag2| {
-            diag1.span.primary_span().cmp(&diag2.span.primary_span())
-        });
+        mbcx.errors_buffer.sort_by_key(|diag| diag.span.primary_span());
 
         if tcx.migrate_borrowck() {
             match tcx.borrowck(def_id).signalled_any_error {