On Wed, Mar 26, 2025 at 6:15 PM Benno Lossin <benno.lossin@xxxxxxxxx> wrote: > > On Wed Mar 26, 2025 at 11:09 PM CET, Tamir Duberstein wrote: > > On Wed, Mar 26, 2025 at 5:09 PM Benno Lossin <benno.lossin@xxxxxxxxx> wrote: > >> On Wed Mar 26, 2025 at 8:06 PM CET, Tamir Duberstein wrote: > >> > On Wed, Mar 26, 2025 at 1:36 PM Benno Lossin <benno.lossin@xxxxxxxxx> wrote: > >> >> On Wed Mar 26, 2025 at 5:57 PM CET, Tamir Duberstein wrote: > >> >> > > >> >> > Yeah, we should do this - but again: not relevant in this discussion. > >> >> > >> >> I think it's pretty relevant. > >> > > >> > It's not relevant because we're no longer talking about transmuting > >> > pointer to pointer. The two options are: > >> > 1. transmute reference to reference. > >> > 2. coerce reference to pointer, `as` cast pointer to pointer (triggers > >> > `ptr_as_ptr`), reborrow pointer to reference. > >> > > >> > If anyone can help me understand why (2) is better than (1), I'd > >> > certainly appreciate it. > >> > >> I am very confident that (2) is correct. With (1) I'm not sure (see > >> above), so that's why I mentioned it. > > > > Can you help me understand why you're confident about (2) but not (1)? > > My explanation from above explains why I'm not confident about (1): > > For ptr-to-int transmutes, I know that they will probably remove > provenance, hence I am a bit cautious about using them for ptr-to-ptr or > ref-to-ref. > > The reason I'm confident about (2) is that that is the canonical way to > cast the type of a reference pointing to an `!Sized` value. Do you have a citation, other than the transmute doc?
