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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/46004] New: [C++0x] template constructor used to copy object Date: Wed, 13 Oct 2010 12:01:00 -0000 [thread overview] Message-ID: <bug-46004-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46004 Summary: [C++0x] template constructor used to copy object Product: gcc Version: 4.6.0 Status: UNCONFIRMED Keywords: rejects-valid Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned@gcc.gnu.org ReportedBy: redi@gcc.gnu.org CC: jason@gcc.gnu.org [class.copy]p7 says "A member function template is never instantiated to perform the copy of a class object to an object of its class type." struct B { int i; template<typename I> explicit B(I&& ii) : i(ii) { } B(const B&) = default; }; int main() { B b(0); B bb(b); } cc.cc: In constructor 'B::B(I&&) [with I = B&]': cc.cc:15:11: instantiated from here cc.cc:7:25: error: cannot convert 'B' to 'int' in initialization Even with an explicitly declared copy constructor the template is still chosen. This only happens if the template constructor parameter type is an rvalue-reference, so only affects C++0x mode. In http://gcc.gnu.org/viewcvs?view=revision&revision=165144 I had to workaround this behaviour by replacing the template constructor by a pair of overloads, one for lvalues and one for rvalues: explicit B(const int& ii) : i(ii) { } explicit B(int&& ii) : i(ii) { }
next reply other threads:[~2010-10-13 12:01 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-10-13 12:01 redi at gcc dot gnu.org [this message] 2010-10-13 13:10 ` [Bug c++/46004] " jason at gcc dot gnu.org 2010-10-13 13:25 ` redi at gcc dot gnu.org 2011-09-23 13:08 ` redi at gcc dot gnu.org 2011-10-31 12:21 ` paolo.carlini at oracle dot com
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