[Bug c++/31156] New: creates reference to copy constructor on use of temporary object

["charles at vmware dot com" <gcc-bugzilla at gcc dot gnu dot org>]

The following code fails to compile:

>>>> begin
#include <iostream>

class Foo
{
        Foo(const Foo&); // private
public:
        Foo(int x) { }
};

std::ostream &operator <<(std::ostream &out, const Foo &)
{
        return out;
}

int main()
{
        std::cout << Foo(5);
}

// test.cpp:5: error: 'Foo::Foo(const Foo&)' is private
// test.cpp:17: error: within this context
<<<< end

It does compile with EDG's C++ frontend.

reproduced on gcc version 4.1.2 (Gentoo 4.1.2)
reproduced on gcc version 4.1.1 (Gentoo 4.1.1-r3)
_not_ reproduced on gcc version 3.3.6 (Debian 1:3.3.6-15)

The following also fails on (Debian 4.1.1-21):

>>>> begin
class Foo
{
        Foo(const Foo&); // private
public:
        Foo(int x) { }
};

void foo(const Foo &) { }

int main()
{
        foo(Foo(5));
}

// test.cpp:3: error: 'Foo::Foo(const Foo&)' is private
// test.cpp:12: error: within this context
<<<< end

Likewise, the following test, demonstrating that it's based on temporaries,
successfully compiles:

>>>> begin
class Foo
{
        Foo(const Foo&); // private
public:
        Foo(int x) { }
};

void foo(const Foo &) { }

int main()
{
        Foo f(5);
        foo(f);
}
<<<< end


-- 
           Summary: creates reference to copy constructor on use of
                    temporary object
           Product: gcc
           Version: 4.1.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: charles at vmware dot com
 GCC build triplet: gcc version 4.1.2 20061115 (prerelease) (Debian 4.1.1-
                    21)
  GCC host triplet: gcc version 4.1.2 20061115 (prerelease) (Debian 4.1.1-
                    21)
GCC target triplet: gcc version 4.1.2 20061115 (prerelease) (Debian 4.1.1-
                    21)


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31156