Auto merge of #83726 - the8472:large-trustedlen-fail-fast, r=kennytm

panic early when `TrustedLen` indicates a `length > usize::MAX`

Changes `TrustedLen` specializations to immediately panic when `size_hint().1 == None`.

As far as I can tell this is ~not a change~ a minimal change in observable behavior for anything except ZSTs because the fallback path would go through `extend_desugared()` which tries to `reserve(lower_bound)` which already is `usize::MAX` and that would also lead to a panic. Before it might have popped somewhere between zero and a few elements from the iterator before panicking while it now panics immediately.

Overall this should reduce codegen by eliminating the fallback paths.

While looking into the `with_capacity()` behavior I also noticed that its documentation didn't have a *Panics* section, so I added that.

0 files changed, 0 insertions, 0 deletions