Is it possible to replace following ref-qualifiers with concepts?
That is, instead of
struct S
{
void func() && {}
void func() & {}
};
have something like this
struct S
{
void func() requires rvalue_concept< decltype(*this) > {}
void func() requires lvalue_concept< decltype(*this) > {}
};
Note: This is not a duplicate of How can I make a forwarding-reference parameter bind only to rvalue references? because my question is about checking whether the struct S is used as an r-value-reference, but the other question is about a function which shall only accept r-value-references.
Is it possible to replace ref-qualifiers with concepts?
You can use the explicit object parameter syntax introduced in c++23, which allows us to deduce the type of this.
With that, you could write:
template<typename T>
concept rvalue_concept = std::is_rvalue_reference_v<T&&>;
template<typename T>
concept lvalue_concept = !rvalue_concept<T>;
struct S
{
template<typename Self>
void func(this Self&& self) requires rvalue_concept<Self>
{
std::cout << "rvalue version called\n";
}
template<typename Self>
void func(this Self&& self) requires lvalue_concept<Self>
{
std::cout << "lvalue version called\n";
}
};