substructural type (affine type).cxx

template<auto, auto>                                         
struct ADLType {
    friend consteval auto ADLFunc(ADLType, auto...);
};

template<auto InstanceIdentifier, auto x>
struct InjectDefinitionForADLFunc {
    friend consteval auto ADLFunc(ADLType<InstanceIdentifier, x>, auto...) {}
};

template<auto InstanceIdentifier, auto x = 0, auto = []{}>
consteval auto ExtractThenUpdateCurrentState()->decltype(x) {
    if constexpr (requires { ADLFunc(ADLType<InstanceIdentifier, x>{}); })
        return ExtractThenUpdateCurrentState<InstanceIdentifier, x + 1>();
    else 
        InjectDefinitionForADLFunc<InstanceIdentifier, x>{};
    return x;
}

template<auto InstanceIdentifier = []{}>
struct AffineType {};

template<auto InstanceIdentifier, auto x = ExtractThenUpdateCurrentState<InstanceIdentifier>()>
auto Use(AffineType<InstanceIdentifier>) requires (x == 0) {}

auto main()->int {
    auto x = AffineType{};
    auto y = AffineType{};

    Use(x);
    Use(y);

    // Use(x); <- type level failure
}