From 77f31ef2b29e0ff16b9db8907327741c057bea8e Mon Sep 17 00:00:00 2001
From: Yuri Astrakhan <YuriAstrakhan@gmail.com>
Date: Thu, 25 Jan 2024 20:56:52 -0500
Subject: [PATCH] use checked_add for upper bound

---
 library/core/src/iter/adapters/intersperse.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/core/src/iter/adapters/intersperse.rs b/library/core/src/iter/adapters/intersperse.rs
index f436fe02dca..c97a59b614f 100644
--- a/library/core/src/iter/adapters/intersperse.rs
+++ b/library/core/src/iter/adapters/intersperse.rs
@@ -200,10 +200,10 @@ fn intersperse_size_hint<I>(iter: &I, started: bool, next_is_some: bool) -> (usi
         lo.saturating_sub(!started as usize)
             .saturating_add(next_is_some as usize)
             .saturating_add(lo),
-        hi.map(|hi| {
+        hi.and_then(|hi| {
             hi.saturating_sub(!started as usize)
                 .saturating_add(next_is_some as usize)
-                .saturating_add(hi)
+                .checked_add(hi)
         }),
     )
 }