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* [Bug c++/68888] No Warning when converting an array of a subclass to its parent [not found] <bug-68888-4@http.gcc.gnu.org/bugzilla/> @ 2021-08-10 2:30 ` pinskia at gcc dot gnu.org 2021-08-10 10:25 ` redi at gcc dot gnu.org 2021-10-27 5:14 ` egallager at gcc dot gnu.org 2 siblings, 0 replies; 3+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-08-10 2:30 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68888 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |diagnostic Severity|normal |enhancement ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/68888] No Warning when converting an array of a subclass to its parent [not found] <bug-68888-4@http.gcc.gnu.org/bugzilla/> 2021-08-10 2:30 ` [Bug c++/68888] No Warning when converting an array of a subclass to its parent pinskia at gcc dot gnu.org @ 2021-08-10 10:25 ` redi at gcc dot gnu.org 2021-10-27 5:14 ` egallager at gcc dot gnu.org 2 siblings, 0 replies; 3+ messages in thread From: redi at gcc dot gnu.org @ 2021-08-10 10:25 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68888 Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2021-08-10 Ever confirmed|0 |1 --- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- This is undefined behaviour, and should definitely warn (and UBsan should give an error too). The implicit conversion sequence of array-to-pointer decay followed by derived-to-base conversion should warn. If the derived-to-base conversion is really desired (because no pointer arithmetic will be done on the result) then users can get a pointer to the first element of the array explicitly, so there is no implicit decay e.g. any of these would not warn: go(&bs[0]); go(&*bs); go((B*)bs); go(std::begin(bs)); (of course the code would still have undefined behaviour due to the arithmetic in go, but it wouldn't warn because there's no implicit decay). ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/68888] No Warning when converting an array of a subclass to its parent [not found] <bug-68888-4@http.gcc.gnu.org/bugzilla/> 2021-08-10 2:30 ` [Bug c++/68888] No Warning when converting an array of a subclass to its parent pinskia at gcc dot gnu.org 2021-08-10 10:25 ` redi at gcc dot gnu.org @ 2021-10-27 5:14 ` egallager at gcc dot gnu.org 2 siblings, 0 replies; 3+ messages in thread From: egallager at gcc dot gnu.org @ 2021-10-27 5:14 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68888 Eric Gallager <egallager at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |egallager at gcc dot gnu.org --- Comment #2 from Eric Gallager <egallager at gcc dot gnu.org> --- Any ideas for a proposed name for the flag that would control this warning? ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-10-27 5:14 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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[not found] <bug-68888-4@http.gcc.gnu.org/bugzilla/>
2021-08-10 2:30 ` [Bug c++/68888] No Warning when converting an array of a subclass to its parent pinskia at gcc dot gnu.org
2021-08-10 10:25 ` redi at gcc dot gnu.org
2021-10-27 5:14 ` egallager at gcc dot gnu.org
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