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From: "de34 at live dot cn" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/104264] New: __is_trivially_copyable fails to report non-recursively trivially copyable classes Date: Fri, 28 Jan 2022 03:34:55 +0000 [thread overview] Message-ID: <bug-104264-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104264 Bug ID: 104264 Summary: __is_trivially_copyable fails to report non-recursively trivially copyable classes Product: gcc Version: 12.0 Status: UNCONFIRMED Keywords: accepts-invalid, rejects-valid Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: de34 at live dot cn Target Milestone: --- The current definition of trivially copyable class ([class.prop] /2) is not recursive. I.e. a trivially copyable class may have a base class or data member of a non-trivially copyable class type. The following example is accepted by clang, msvc, and icc, but rejected by gcc (all of which use __is_trivially_copyable). Perhaps gcc considers Supressor as non-trivially copyable because it has a non-trivially copyable data member. struct Weird { Weird() = default; Weird(const Weird&) = default; Weird &operator=(const Weird&) = default; // non-trivial constexpr Weird(Weird&&) noexcept {} constexpr Weird &operator=(Weird&&) noexcept { return *this; } }; struct Supressor { Weird w; Supressor() = default; Supressor(const Supressor&) = default; Supressor &operator=(const Supressor&) = default; // move functions are supressed // non-trivial move functions are not called }; int main() { static_assert(!__is_trivially_copyable(Weird), ""); static_assert(__is_trivially_copyable(Supressor), ""); } Compiler Explorer link: https://gcc.godbolt.org/z/4o1vPdz86 The issue might be related to CWG 2463 (https://wg21.link/cwg2463). CWG DR 1734 seems unrelated,
next reply other threads:[~2022-01-28 3:34 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-28 3:34 de34 at live dot cn [this message] 2023-09-23 13:44 ` [Bug c++/104264] " jason at gcc dot gnu.org
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