From 7af83dcd03b0de52bd67546b51b6a4f7ee98fd72 Mon Sep 17 00:00:00 2001
From: Justin Ridgewell <justin@ridgewell.name>
Date: Wed, 22 May 2019 23:51:09 -0400
Subject: [PATCH] Simplify CharIndices.next

Char.len_utf8 is stable since #49698, making this a little easier to follow.
---
 src/libcore/str/mod.rs | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 0e8a2da3c110d..bf35541c28daa 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -663,16 +663,10 @@ impl<'a> Iterator for CharIndices<'a> {
 
     #[inline]
     fn next(&mut self) -> Option<(usize, char)> {
-        let pre_len = self.iter.iter.len();
-        match self.iter.next() {
-            None => None,
-            Some(ch) => {
-                let index = self.front_offset;
-                let len = self.iter.iter.len();
-                self.front_offset += pre_len - len;
-                Some((index, ch))
-            }
-        }
+        let ch = self.iter.next()?;
+        let index = self.front_offset;
+        self.front_offset += ch.len_utf8();
+        Some((index, ch))
     }
 
     #[inline]