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From: "jengelh at inai dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/103923] New: is_invocable<const T &, ...> inexplicably fails Date: Wed, 05 Jan 2022 23:16:17 +0000 [thread overview] Message-ID: <bug-103923-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103923 Bug ID: 103923 Summary: is_invocable<const T &, ...> inexplicably fails Product: gcc Version: 11.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: jengelh at inai dot de Target Milestone: --- Input: #include <cstdio> #include <typeinfo> #include <type_traits> #include <unordered_map> struct T { struct K { bool operator==(const K &) const { return 0; } bool operator<(const K &) const { return 0; } }; struct H { auto operator()(const K &) const { return 0; } }; std::unordered_map<T::K, int, T::H> m; }; int main() { printf("%d\n", std::is_invocable_v<const T::H &, const T::K &>); printf("%d\n", std::is_invocable_v<T::H, const T::K &>); //T().m[T::K()]; // for extra fun } Output: GNU C++17 (SUSE Linux) version 11.2.1 20211124 [revision 7510c23c1ec53aa4a62705f0384079661342ff7b] (x86_64-suse-linux) compiled by GNU C version 11.2.1 20211124 [revision 7510c23c1ec53aa4a62705f0384079661342ff7b], GMP version 6.2.1, MPFR version 4.1.0-p7, MPC version 1.2.1, isl version isl-0.24-GMP 0 1 Expected output: 1 1 Expectation based on it being possible to invoke on a const H &: { T::H h; const T::H &hh = h; hh(T::K()); }
next reply other threads:[~2022-01-05 23:16 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-05 23:16 jengelh at inai dot de [this message] 2022-01-05 23:19 ` [Bug libstdc++/103923] " pinskia at gcc dot gnu.org 2022-01-06 9:23 ` redi at gcc dot gnu.org 2022-01-06 9:31 ` redi at gcc dot gnu.org 2022-01-06 9:37 ` redi at gcc dot gnu.org 2022-01-06 9:39 ` redi at gcc dot gnu.org 2022-01-06 9:46 ` redi at gcc dot gnu.org 2022-01-06 14:30 ` redi at gcc dot gnu.org 2022-01-06 14:53 ` redi at gcc dot gnu.org 2022-01-06 16:00 ` redi at gcc dot gnu.org
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