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From: "b.stanimirov at abv dot bg" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/108714] New: Algorithms in <algorithm> require
 predicates to be copyable
Date: Wed, 08 Feb 2023 08:56:27 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108714

            Bug ID: 108714
           Summary: Algorithms in <algorithm> require predicates to be
                    copyable
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: b.stanimirov at abv dot bg
  Target Milestone: ---

Simple repro:

```
#include <algorithm>
#include <vector>

struct noncopyable {
    noncopyable();
    noncopyable(const noncopyable&) =3D delete;
    noncopyable(noncopyable&&) noexcept =3D default;
    template <typename T>
    bool operator()(const T&);
};

bool all_of_vec(const std::vector<int>& vec) {
    return std::all_of(vec.begin(), vec.end(), noncopyable{});
}
```

This does not compile, because the predicate to `all_of` is not copyable. T=
he
same error appears for all other algorithms which allow a predicate.

It does compile and work and expected with Microsoft STL and with libc++

Live demo showing compilation errors with libstdc++ and successful compilat=
ion
with libc++ and Microsoft STL: https://godbolt.org/z/xaa35G35e=