public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
* [Bug c++/99399] New: why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC @ 2021-03-05 7:20 xmh970252187 at gmail dot com 2021-03-05 7:22 ` [Bug c++/99399] " xmh970252187 at gmail dot com ` (5 more replies) 0 siblings, 6 replies; 7+ messages in thread From: xmh970252187 at gmail dot com @ 2021-03-05 7:20 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99399 Bug ID: 99399 Summary: why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC Product: gcc Version: 10.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: xmh970252187 at gmail dot com Target Milestone: --- template<typename...T> struct A:T...{ using T::T...; }; int main() { } This should have to be well-formed code is rejected by GCC while Clang accepts it. Here is the result (https://godbolt.org/z/a583Po) As per [temp.variadic#5.2] > In a using-declaration; the pattern is a using-declarator. Which means the pattern is `T::T`. As per [temp.variadic#7]: > The pattern of a pack expansion shall name one or more packs that are not expanded by a nested pack expansion; such packs are called unexpanded packs in the pattern. All of the packs expanded by a pack expansion shall have the same number of arguments specified. There are two unexpanded packs in the pattern and they have the same number of arguments. As per [temp.variadic#6] and [temp.variadic#8.1] > For the purpose of determining whether a pack satisfies a rule regarding entities other than packs, the pack is considered to be the entity that would result from an instantiation of the pattern in which it appears. > if the pack is a template parameter pack, the element is a template parameter ([temp.param]) of the corresponding kind (type or non-type) designating the ith corresponding type or value template argument; That means `T` in the pattern would be considered as a type template parameter designating the corresponding template type argument. Eventually, as per [class.qual#2.2] > In a lookup in which function names are not ignored26 and the nested-name-specifier nominates a class C: >> in a using-declarator of a using-declaration that is a member-declaration, if the name specified after the nested-name-specifier is the same as the identifier or the simple-template-id's template-name in the last component of the nested-name-specifier Assume the template parameters would be `class T0, class T1,class T2, ... ,class Tn` , the result of instantiating the pattern `T::T` will produce the list `T0::T0,T1::T1,T2::T2,...Tn::Tn`, which will satisfy the above rule. Hence, the result of instantiating `T::T` can be considered to nominate the corresponding constructor of the class named in the nested-name-specifier. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/99399] why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC 2021-03-05 7:20 [Bug c++/99399] New: why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC xmh970252187 at gmail dot com @ 2021-03-05 7:22 ` xmh970252187 at gmail dot com 2021-08-12 21:52 ` pinskia at gcc dot gnu.org ` (4 subsequent siblings) 5 siblings, 0 replies; 7+ messages in thread From: xmh970252187 at gmail dot com @ 2021-03-05 7:22 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99399 --- Comment #1 from jim x <xmh970252187 at gmail dot com> --- All the quotes refer to n4861. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/99399] why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC 2021-03-05 7:20 [Bug c++/99399] New: why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC xmh970252187 at gmail dot com 2021-03-05 7:22 ` [Bug c++/99399] " xmh970252187 at gmail dot com @ 2021-08-12 21:52 ` pinskia at gcc dot gnu.org 2021-12-08 14:12 ` marxin at gcc dot gnu.org ` (3 subsequent siblings) 5 siblings, 0 replies; 7+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-08-12 21:52 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99399 --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Seems fixed in GCC 11+. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/99399] why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC 2021-03-05 7:20 [Bug c++/99399] New: why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC xmh970252187 at gmail dot com 2021-03-05 7:22 ` [Bug c++/99399] " xmh970252187 at gmail dot com 2021-08-12 21:52 ` pinskia at gcc dot gnu.org @ 2021-12-08 14:12 ` marxin at gcc dot gnu.org 2021-12-08 15:46 ` pinskia at gcc dot gnu.org ` (2 subsequent siblings) 5 siblings, 0 replies; 7+ messages in thread From: marxin at gcc dot gnu.org @ 2021-12-08 14:12 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99399 Martin Liška <marxin at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Keywords|needs-bisection | Status|UNCONFIRMED |NEW Last reconfirmed| |2021-12-08 Known to work| |12.0 CC| |marxin at gcc dot gnu.org --- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> --- Fixed by r11-6942-g9cd7c32549fa3348. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/99399] why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC 2021-03-05 7:20 [Bug c++/99399] New: why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC xmh970252187 at gmail dot com ` (2 preceding siblings ...) 2021-12-08 14:12 ` marxin at gcc dot gnu.org @ 2021-12-08 15:46 ` pinskia at gcc dot gnu.org 2021-12-08 15:47 ` pinskia at gcc dot gnu.org 2021-12-09 5:52 ` pinskia at gcc dot gnu.org 5 siblings, 0 replies; 7+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-12-08 15:46 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99399 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |FIXED --- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- g++.dg/cpp1z/inh-ctor39.C testcase covers this one so closing. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/99399] why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC 2021-03-05 7:20 [Bug c++/99399] New: why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC xmh970252187 at gmail dot com ` (3 preceding siblings ...) 2021-12-08 15:46 ` pinskia at gcc dot gnu.org @ 2021-12-08 15:47 ` pinskia at gcc dot gnu.org 2021-12-09 5:52 ` pinskia at gcc dot gnu.org 5 siblings, 0 replies; 7+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-12-08 15:47 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99399 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |11.0 ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/99399] why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC 2021-03-05 7:20 [Bug c++/99399] New: why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC xmh970252187 at gmail dot com ` (4 preceding siblings ...) 2021-12-08 15:47 ` pinskia at gcc dot gnu.org @ 2021-12-09 5:52 ` pinskia at gcc dot gnu.org 5 siblings, 0 replies; 7+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-12-09 5:52 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99399 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|FIXED |DUPLICATE --- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Dup of bug 80417. *** This bug has been marked as a duplicate of bug 80417 *** ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2021-12-09 5:52 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-03-05 7:20 [Bug c++/99399] New: why does not a pack expansion that is a using-delcaration which intends to introduce the base classes's constructor accept by GCC xmh970252187 at gmail dot com 2021-03-05 7:22 ` [Bug c++/99399] " xmh970252187 at gmail dot com 2021-08-12 21:52 ` pinskia at gcc dot gnu.org 2021-12-08 14:12 ` marxin at gcc dot gnu.org 2021-12-08 15:46 ` pinskia at gcc dot gnu.org 2021-12-08 15:47 ` pinskia at gcc dot gnu.org 2021-12-09 5:52 ` pinskia at gcc dot gnu.org
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).