From 3eddc743f2ca3dbd5a5a41e3c2477ca9fbc7b97c Mon Sep 17 00:00:00 2001
From: Konrad Borowski <konrad@borowski.pw>
Date: Wed, 5 Dec 2018 16:44:10 +0100
Subject: [PATCH] Use inner iterator may_have_side_effect for Cloned

Previous implementation wasn't correct, as an inner iterator
could have had side effects.
---
 src/libcore/iter/mod.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/libcore/iter/mod.rs b/src/libcore/iter/mod.rs
index 62e1f9fcb640c..de7ab8843daed 100644
--- a/src/libcore/iter/mod.rs
+++ b/src/libcore/iter/mod.rs
@@ -602,7 +602,9 @@ unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Cloned<I>
     }
 
     #[inline]
-    fn may_have_side_effect() -> bool { false }
+    fn may_have_side_effect() -> bool {
+        I::may_have_side_effect()
+    }
 }
 
 #[unstable(feature = "trusted_len", issue = "37572")]