Consider the following code:
class Outer
{
class Inner
{
public:
Inner(Inner&& i):outers(std::move(i.outers)),test(std::move(test))
{}
void addOuter(const Outer& o) {outers.push_back(std::move(o));}
private:
std::vector<Outer> outers;
std::unique_ptr<std::string> test;
};
public:
Outer(Outer&& o):inners(std::move(o.inners))
{}
private:
std::vector<Inner> inners;
};
When I try to compile the code above on Visual Studio 2012, I get the following error:
Error 1 error C2248: 'std::unique_ptr<_Ty>::unique_ptr' : cannot access private member declared in class 'std::unique_ptr<_Ty>'
Apparently the compiler invokes the copy constructor instead of the move constructor in the push_back found in the addOuter
method. Is this a compiler bug? If not why, for this specific case, isn't the move constructor called?
Because
o
is passed as aconst
reference toaddOuter
.