C++20 concepts are not being removed

[Karthikeya Kona]

Declarations of concepts, a feature introduced in C++ 20, are not being removed.

In the example below, the Printable concept is unused and should be removed.

input.cpp:

#include <iostream>
#include <concepts>

template<typename T>
concept Addable = requires(T a, T b) {
    {a + b} -> std::same_as<T>;
};

template<typename T>
concept Printable = requires(T t) { // this concept is unused but it is not removed
    {std::cout << t};
};

template<Addable T>
T add(T a, T b) {
    return a + b;
}

int main() {
    std::cout << add(5, 3) << std::endl;
    std::cout << add(2.5, 3.7) << std::endl;
    return 0;
}

result.cpp (identical to input):

#include <iostream>
#include <concepts>

template<typename T>
concept Addable = requires(T a, T b) {
    {a + b} -> std::same_as<T>;
};

template<typename T>
concept Printable = requires(T t) { // this concept is unused but it is not removed
    {std::cout << t};
};

template<Addable T>
T add(T a, T b) {
    return a + b;
}

int main() {
    std::cout << add(5, 3) << std::endl;
    std::cout << add(2.5, 3.7) << std::endl;
    return 0;
}