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From: "nickhuang99 at hotmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/104255] New: parsing trailing return type fails with parameter pack expansion when two parameter packs at present Date: Wed, 26 Jan 2022 22:51:32 +0000 [thread overview] Message-ID: <bug-104255-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104255 Bug ID: 104255 Summary: parsing trailing return type fails with parameter pack expansion when two parameter packs at present Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: nickhuang99 at hotmail dot com Target Milestone: --- The following template function causes error when we define trailing return type which is identical to what function body actual returning ( https://www.godbolt.org/z/n3nbW785o ) template<size_t N, size_t...Is> constexpr size_t identity2(index_sequence<Is...>seq){ return N; } template<size_t...Seq1, size_t...Seq2> auto getSeq2(index_sequence<Seq1...>seq1, index_sequence<Seq2...>seq2) // this trailing return type causing parsing error of parameter pack ->index_sequence<(identity2<Seq1, Seq2...>(seq2))...>; { return index_sequence<(identity2<Seq1, Seq2...>(seq2))...>{}; } As a positive example against above, when "identity1" takes no parameter pack as template argument, it works fine. template<size_t N> constexpr size_t identity1(){ return N; } template<size_t...Indexes> auto getSeq1(index_sequence<Indexes...>indexes) // trailing return type works, no need to define function body at all. ->index_sequence<(identity1<Indexes>())...>; clang13/MSVC all work as expected.
next reply other threads:[~2022-01-26 22:51 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-26 22:51 nickhuang99 at hotmail dot com [this message] 2022-01-27 20:49 ` [Bug c++/104255] " nickhuang99 at hotmail dot com 2022-01-28 15:11 ` ppalka at gcc dot gnu.org 2022-01-28 18:48 ` [Bug c++/104255] parsing function signature fails when it uses a function parameter outside of an unevaluated context nickhuang99 at hotmail dot com 2022-01-28 22:40 ` nickhuang99 at hotmail dot com 2022-02-02 15:13 ` ppalka at gcc dot gnu.org 2023-10-06 13:42 ` ppalka at gcc dot gnu.org 2023-11-08 21:54 ` ppalka at gcc dot gnu.org 2023-11-08 21:55 ` ppalka at gcc dot gnu.org 2024-02-27 5:12 ` barry.revzin at gmail dot com
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