[Bug libstdc++/118185] New: ranges::clamp doesn't perfectly forward its projected arguments

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118185

            Bug ID: 118185
           Summary: ranges::clamp doesn't perfectly forward its projected
                    arguments
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ppalka at gcc dot gnu.org
                CC: de34 at live dot cn, hewillk at gmail dot com, ppalka at gcc dot gnu.org,
                    unassigned at gcc dot gnu.org, webrown.cpp at gmail dot com
        Depends on: 100249
  Target Milestone: ---

+++ This bug was initially created as a clone of Bug #100249 +++

(In reply to Jiang An from comment #13)
> This is not completely fixed.
> 
> See
> - https://github.com/microsoft/STL/issues/3970#issuecomment-1681524306
> - https://gcc.godbolt.org/z/3fsdbTx5Y

#include <algorithm>
#include <concepts>

struct Comp {
    bool operator()(const int&& x, const int&& y) const {
        return x < y;
    }
    bool operator()(const int&& x, int& y) const {
        return x < y;
    }
    bool operator()(int& x, const int&& y) const {
        return x < y;
    }
    bool operator()(int& x, int& y) const {
        return x < y;
    }
    bool operator()(std::same_as<const int&> auto && x, std::same_as<const
int&> auto && y) const {
        return x < y;
    }
};

struct Proj {
    const int&& operator()(const int& x) const { return std::move(x); }
};


static_assert(std::indirect_strict_weak_order<Comp, std::projected<const int*,
Proj>>);

void f() {
    std::ranges::clamp(0, 1, 2, Comp{}, Proj{});
}


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100249
[Bug 100249] missing forwarding std::__invoke result in ranges::is_permutation
and ranges::clamp