From 154d6bb19872f513b08d0fc51716fbe6c10c2a03 Mon Sep 17 00:00:00 2001
From: John Maddock <john@johnmaddock.co.uk>
Date: Mon, 26 Jan 2004 11:29:07 +0000
Subject: [PATCH] When we have a compressed pair of two types that are the
 same, and both empty, then we must still have two distict objects in the
 pair.

[SVN r21958]
---
 include/boost/detail/compressed_pair.hpp    | 14 +++++++++-----
 include/boost/detail/ob_compressed_pair.hpp | 12 +++++++-----
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/include/boost/detail/compressed_pair.hpp b/include/boost/detail/compressed_pair.hpp
index 9c9ac7e..af1e9bd 100644
--- a/include/boost/detail/compressed_pair.hpp
+++ b/include/boost/detail/compressed_pair.hpp
@@ -8,6 +8,9 @@
 // compressed_pair: pair that "compresses" empty members
 // (see libs/utility/compressed_pair.htm)
 //
+// JM changes 25 Jan 2004:
+// For the case where T1 == T2 and both are empty, then first() and second()
+// should return different objects.
 // JM changes 25 Jan 2000:
 // Removed default arguments from compressed_pair_switch to get
 // C++ Builder 4 to accept them
@@ -268,20 +271,21 @@ namespace details
 
       compressed_pair_imp() {}
 
-      compressed_pair_imp(first_param_type x, second_param_type)
-         : first_type(x) {}
+      compressed_pair_imp(first_param_type x, second_param_type y)
+         : first_type(x), m_second(y) {}
 
       compressed_pair_imp(first_param_type x)
-         : first_type(x) {}
+         : first_type(x), m_second(x) {}
 
       first_reference       first()       {return *this;}
       first_const_reference first() const {return *this;}
 
-      second_reference       second()       {return *this;}
-      second_const_reference second() const {return *this;}
+      second_reference       second()       {return m_second;}
+      second_const_reference second() const {return m_second;}
 
       void swap(::boost::compressed_pair<T1,T2>&) {}
    private:
+      T2 m_second;
    };
 
    // 5    T1 == T2 and are not empty:   //JM
diff --git a/include/boost/detail/ob_compressed_pair.hpp b/include/boost/detail/ob_compressed_pair.hpp
index c316a06..727acab 100644
--- a/include/boost/detail/ob_compressed_pair.hpp
+++ b/include/boost/detail/ob_compressed_pair.hpp
@@ -292,22 +292,24 @@ public:
    typedef typename call_traits<second_type>::const_reference second_const_reference;
 
             compressed_pair_4() : T1() {}
-            compressed_pair_4(first_param_type x, second_param_type) : T1(x) {}
+            compressed_pair_4(first_param_type x, second_param_type y) : T1(x), m_second(y) {}
    // only one single argument constructor since T1 == T2
-   explicit compressed_pair_4(first_param_type x) : T1(x) {}
+   explicit compressed_pair_4(first_param_type x) : T1(x), m_second(x) {}
    compressed_pair_4(const ::boost::compressed_pair<T1,T2>& x)
-      : T1(x.first()){}
+      : T1(x.first()), m_second(x.second()) {}
 
    first_reference       first()       { return *this; }
    first_const_reference first() const { return *this; }
 
-   second_reference       second()       { return *this; }
-   second_const_reference second() const { return *this; }
+   second_reference       second()       { return m_second; }
+   second_const_reference second() const { return m_second; }
 
    void swap(compressed_pair_4& y)
    {
       // no need to swap empty base classes:
    }
+private:
+   T2 m_second;
 };
 
 // T1 == T2, not empty