From 40570911bccf451d6fc76426d912c7153bfb7587 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Sun, 29 Mar 2026 15:24:41 +0200
Subject: [PATCH] Avoid aliasing in merge scan

---
 include/boost/container/experimental/segmented_merge.hpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/boost/container/experimental/segmented_merge.hpp b/include/boost/container/experimental/segmented_merge.hpp
index cd2ec61..2d4c499 100644
--- a/include/boost/container/experimental/segmented_merge.hpp
+++ b/include/boost/container/experimental/segmented_merge.hpp
@@ -43,9 +43,10 @@ struct merge_default_less
 };
 
 template <class FwdIt, class Sent, class InIter2, class Sent2, class OutIter, class Comp>
-OutIter merge_scan(FwdIt first, Sent last, InIter2& first2, Sent2 last2, OutIter result, Comp comp,
+OutIter merge_scan(FwdIt first, Sent last, InIter2& first2_out, Sent2 last2, OutIter result, Comp comp,
    non_segmented_iterator_tag)
 {
+   InIter2 first2 = first2_out;
    while(first != last && first2 != last2) {
       if(comp(*first2, *first)) {
          *result = *first2;
@@ -57,6 +58,7 @@ OutIter merge_scan(FwdIt first, Sent last, InIter2& first2, Sent2 last2, OutIter
       }
       ++result;
    }
+   first2_out = first2;
    return (segmented_copy)(first, last, result);
 }