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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/98835] False positive -Wclass-memaccess with class with ref-qualified copy-assignment operator Date: Tue, 26 Jan 2021 19:38:53 +0000 [thread overview] Message-ID: <bug-98835-4-ZJ31Pnkc8o@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-98835-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98835 Martin Sebor <msebor at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Keywords| |diagnostic CC| |msebor at gcc dot gnu.org Resolution|--- |INVALID --- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> --- The warning is issued on the basis that the left-hand operand of Bad's assignment cannot be a temporary. I.e., that this isn't valid: Bad() = Bad(). In the modified test case below the warning detects the memcpy call bypassing the constraint the assignment operator puts on assigning to objects of the class. So unless there's a compelling use case showing otherwise I'm inclined to say the warning is justified and helpful here (its wording shouldn't be expected to perfectly reflect all the subtleties involved in the decision). There isn't a test case for this in the test suite so let me add this one. class Bad { public: Bad* operator& () { return this; } Bad & operator=(Bad const &) & = default; }; template<typename T> void test() { static_assert (__has_trivial_copy (T)); // T () = T (); // error memcpy (&T (), &T (), sizeof(T)); // warning } int main() { test<Bad>(); }
next prev parent reply other threads:[~2021-01-26 19:38 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-26 9:33 [Bug c++/98835] New: " jchl at arista dot com 2021-01-26 19:38 ` msebor at gcc dot gnu.org [this message] 2021-02-01 15:48 ` [Bug c++/98835] " cvs-commit at gcc dot gnu.org
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