I'm having a problem compiling code where an explicit user-defined conversion operator isn't being found for a wrapper class. It happens when the wrapper class is storing a reference type
template<typename T>
class Wrapper
{
private:
int dummy_;
T data_;
public:
Wrapper(T data) : data_(data) { dummy_ = 9999; }
explicit operator T&()
{
std::cout << "In operator T&\n";
return data_;
}
};
int main(void)
{
int i = 5;
Wrapper<int &> wi(i);
// Won't compile
std::cout << "value: " << static_cast<int &>(wi) << "\n";
// Prints "9999", since it isn't calling Wrapper::operator T&()
std::cout << "value: " << (int &)(wi) << "\n";
return 0;
}
In the above, the static_cast version won't compile (error: invalid type conversion: "Wrapper<int &>" to "int &"). The C-style cast compiles, but since the operator T& still isn't being called, the result is garbage, more or less.
Both versions work fine with g++ and clang. It works with Intel if the "explicit" is removed. Is this a bug?
EDIT: Actually, seems to happen even if the wrapper doesn't store a reference type (ie, Wrapper<int> wi(i) )
