Rollup merge of rust-lang#81741 - sdroege:zip-trusted-random-access-specialization-panic-safety, r=KodrAus

Increment `self.index` before calling `Iterator::self.a.__iterator_ge… …`t_unchecked` in `Zip` `TrustedRandomAccess` specialization Otherwise if `Iterator::self.a.__iterator_get_unchecked` panics the index would not have been incremented yet and another call to `Iterator::next` would read from the same index again, which is not allowed according to the API contract of `TrustedRandomAccess` for `!Clone`. Fixes rust-lang#81740

Author: Dylan-DPC

library/core/src/iter/adapters/zip.rs

@@ -198,12 +198,13 @@ where
  Some((self.a.__iterator_get_unchecked(i), self.b.__iterator_get_unchecked(i)))
  }
  } else if A::may_have_side_effect() && self.index < self.a.size() {
+ let i = self.index;
+ self.index += 1;
  // match the base implementation's potential side effects
- // SAFETY: we just checked that `self.index` < `self.a.len()`
+ // SAFETY: we just checked that `i` < `self.a.len()`
  unsafe {
- self.a.__iterator_get_unchecked(self.index);
+ self.a.__iterator_get_unchecked(i);
  }
- self.index += 1;
  None
  } else {
  None