[Boost-users] [move] Movable but not copyable bug?

Subject: [Boost-users] [move] Movable but not copyable bug?
From: Mostafa (mostafa_working_away_at_[hidden])
Date: 2014-08-23 20:55:06

Given the following code, if (1) is uncommented then it fails to compile
under C++03 mode yet works in C++11 mode. If commented out, then it
compiles successfully under both modes. (g++ 4.8.2 is being used) Is this
behavior expected or a bug?

#include <boost/move/core.hpp>
#include <boost/move/utility.hpp>

struct Foo
{
     Foo(int x, int y)
     {}

     Foo(BOOST_RV_REF(Foo) rhs)
     {}

private:
     //Purposefully declared and not defined.
     Foo & operator=(Foo);
private:
     BOOST_MOVABLE_BUT_NOT_COPYABLE(Foo)
};

template <typename T>
struct Bar
{
     Bar()
     : f(0, 1)
     {}

     // (1)
     // Bar(Bar const & rhs)
     // : f(rhs.f)
     // {}

     Bar(BOOST_RV_REF(Bar) rhs)
     : f(::boost::move(rhs.f))
     {}

private:
     //Purposefully declared and not defined.
     Bar & operator=(Bar);
private:
     BOOST_COPYABLE_AND_MOVABLE(Bar)
private:
     T f;
};

Foo f1()
{
     // (2)
     // Foo f(0, 1);
     // return f;

     // (3)
     return Foo(0, 1);
}

Bar<Foo> f2()
{
     return Bar<Foo>();
}

int main()
{
     // Foo f( f1() );

     Bar<Foo> b(Bar<Foo>());

     return 0;
}