From 811a2bfe5332081d7145de6c488ea7f6c5cf42a5 Mon Sep 17 00:00:00 2001
From: Nathan West <Lucretiel@users.noreply.github.com>
Date: Wed, 5 Dec 2018 17:46:03 -0800
Subject: Added explainatory comments

---
 src/liballoc/string.rs | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'src/liballoc')

diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index 6962f2ba852..f0a64f4631a 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -1734,6 +1734,9 @@ impl FromIterator<String> for String {
     fn from_iter<I: IntoIterator<Item = String>>(iter: I) -> String {
         let mut iterator = iter.into_iter();
 
+        // Because we're iterating over `String`s, we can avoid at least
+        // one allocation by getting the first string from the iterator
+        // and appending to it all the subsequent strings.
         match iterator.next() {
             None => String::new(),
             Some(mut buf) => {
@@ -1749,6 +1752,9 @@ impl<'a> FromIterator<Cow<'a, str>> for String {
     fn from_iter<I: IntoIterator<Item = Cow<'a, str>>>(iter: I) -> String {
         let mut iterator = iter.into_iter();
 
+        // Because we're iterating over CoWs, we can (potentially) avoid at least
+        // one allocation by getting the first item and appending to it all the
+        // subsequent items.
         match iterator.next() {
             None => String::new(),
             Some(cow) => {
-- 
cgit 1.4.1-3-g733a5