pointer-to-member-function type requires an rvalue

Question

What is the matter of the error, which produces the following code?

struct foo
{
    void call(void (foo::*ptr)()) &&
    {
        (*this.*ptr)();
    }
};

How to fix this error?

Answer 1

由于成员指针具有 rvalue 限定符，因此必须告诉编译器*this将通过在其上使用std::move被视为右值：

(std::move(*this).*ptr)();