std::make_shared needs default constructor to compile by jensa79

Hi,

I tried to use std::make_shared with a class that does only have a user-defined constructor and no default constructor. The compiler reports an error when I try to compile this:

#include <memory>
#include <utility>

struct A
{
A(int) {}
A(A&& a) {}
private:
// uncomment next line to make it work
// A() {}
A(A const&); // not needed, jsut to make sure that it isn't accessed
};

void f()
{
A b(1);
std::shared_ptr<A> a = std::make_shared<A>( std::move(b) );
}

When you declare the default constructor, the compiler does not have a problem and even links it although there is no definition available. I double-checked with gcc 4.6 and this compiler does not report any error.

It turns out that the problem only occurs when I use the compiler switch to turn some warnings into errors. I have prepared a complete project which reproduces the problem. If you remove the warnings in the advanced properties from the option "Treat some warning as errors", everything works fine.

Best regards,
Jens