The code is not compliant with the rules T2 is larger than T1 and no guarantee of the same layout either.
> On May 7, 2022, at 7:54 AM, 'Axel Wagner' via golang-nuts > <golang-nuts@googlegroups.com> wrote: > > > >> On Sat, May 7, 2022 at 1:20 PM Jan Mercl <0xj...@gmail.com> wrote: >> ^ Breaking the unsafe rules enables the code to behave non predictably. > > Sure, that's why I'm asking :) In the hope of either a) learning that it is, > indeed, breaking the rules and thus should not be done, or b) learning that > the rules are incomplete and eventually having them clarified. > >> AFAICT, interior pointers do and must keep the entire allocation block >> alive, > > Is there any "official" documentation on the "must"? > >> but a sufficiently smart compiler is IMO free to ignore setting >> of the 23 value - or allocating the actual storage for .Y in F(), >> because no one can observe it - unless breaking the unsafe rules. > > If internal pointers do, indeed, *must* keep the allocation alive, I can't > see how this would be allowed. After all, the code is unambiguous about > allocating a large object and returning a pointer into it - and if that > pointer must keep the entire object alive, surely a compiler can't just > decide to allocate a smaller one. > > FWIW it seems at least currently, gc is not doing doing it: > https://godbolt.org/z/h74MchcT4 > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/CAEkBMfEFcAWA8TN_UGv_dc8wbM%2BPZ1_ia0g18eGQ4hEju08vLg%40mail.gmail.com. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/7F3F5804-B359-473D-97CA-9E5AD543F337%40ix.netcom.com.
