From a9f234228c1fff54fbc4852dab167ede899944d3 Mon Sep 17 00:00:00 2001
From: Ed Catmur <edward.catmur@mavensecurities.com>
Date: Wed, 22 Feb 2023 19:42:12 +0000
Subject: [PATCH] Explicitly default copy assignment operator

The compiler-generated copy assignment operator is deprecated since C++11 on classes with user-declared copy constructor.

This change allows clean compilation with the -Wdeprecated-copy/-Wdeprecated-copy-with-user-provided-ctor flag.
---
 include/boost/range/sub_range.hpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/boost/range/sub_range.hpp b/include/boost/range/sub_range.hpp
index d1c3b99b0..02c5d45cf 100644
--- a/include/boost/range/sub_range.hpp
+++ b/include/boost/range/sub_range.hpp
@@ -185,6 +185,8 @@ class sub_range_base<ForwardRange, random_access_traversal_tag>
             : base(impl::adl_begin(const_cast<base&>(static_cast<const base&>(r))),
                    impl::adl_end(const_cast<base&>(static_cast<const base&>(r))))
         { }  
+#elif !(defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) || defined(BOOST_NO_CXX11_NON_PUBLIC_DEFAULTED_FUNCTIONS))
+        sub_range(const sub_range& r) = default;
 #endif
 
         template< class ForwardRange2 >