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From: "barry.revzin at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/97934] New: Defaulting <=> breaks other equality operators
Date: Sat, 21 Nov 2020 22:09:27 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97934

            Bug ID: 97934
           Summary: Defaulting <=3D> breaks other equality operators
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: barry.revzin at gmail dot com
  Target Milestone: ---

Reduced example:

#include <compare>

struct X
{
    auto operator<=3D>(X const&) const =3D default;
    auto operator=3D=3D(int i) const;
};

bool f(X x) {
    return x =3D=3D x;
}

gcc trunk rejects this saying no matching candidate. The presence of the
unrelated operator=3D=3D seems to prevent the generation of X::operator=3D=
=3D(X const&)
const from the defaulted <=3D>.=