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From: "de34 at live dot cn" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/111358] New: libstdc++'s optional::and_then and optional::transform are not ADL-proof Date: Sun, 10 Sep 2023 08:18:32 +0000 [thread overview] Message-ID: <bug-111358-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111358 Bug ID: 111358 Summary: libstdc++'s optional::and_then and optional::transform are not ADL-proof Product: gcc Version: 14.0 Status: UNCONFIRMED Keywords: rejects-valid Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: de34 at live dot cn Target Milestone: --- The following program is incorrectly rejected when using libstdc++ (https://godbolt.org/z/eavTYjEdx): ``` #include <optional> namespace fvs { struct Foo {}; void operator*(std::optional<fvs::Foo>) = delete; } int main() { std::optional<fvs::Foo>{}.and_then( [](auto&&){ return std::optional<char>{}; }); std::optional<fvs::Foo>{}.transform( [](auto&&){ return 0; }); } ``` The reason of compilation error is that libstdc++ uses **this in and_then and transform functions, which triggers ADL and finds unwanted operator*(). These monadic operations are currently specified in [optional.monadic] with value(), so they should be ADL-proof.
next reply other threads:[~2023-09-10 8:18 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-09-10 8:18 de34 at live dot cn [this message] 2023-09-10 8:23 ` [Bug libstdc++/111358] " de34 at live dot cn
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