Add slice::check_range by dylni · Pull Request #75207 · rust-lang/rust (original) (raw)

There are 3 more ad-hoc implementations:

• match (range.start_bound(), range.end_bound()) {
  (Excluded(s), Excluded(e)) if s == e => {
  panic!("range start and end are equal and excluded in BTreeMap")
  }
  (Included(s) | Excluded(s), Included(e)	Excluded(e)) if s > e => {
  panic!("range start is greater than range end in BTreeMap")
  }
  _ => {}
  };

The bounds aren't integers, and they're not used for a slice.

• let start = match start {
  Bound::Included(lo) => lo,
  Bound::Excluded(lo) => lo + 1,
  Bound::Unbounded => 0,
  };

| let end = match end { |
| Bound::Included(hi) => hi + 1, |
| Bound::Excluded(hi) => hi, |
| Bound::Unbounded => length, |
| }; |

I don't think this method is allowed to panic, but it also doesn't use a slice.

• let start = match range.start_bound() {
  Bound::Included(ref k) => match self.lookup_index_for(k) {
  Ok(index) | Err(index) => index,
  },
  Bound::Excluded(ref k) => match self.lookup_index_for(k) {
  Ok(index) => index + 1,
  Err(index) => index,
  },
  Bound::Unbounded => 0,
  };

| let end = match range.end_bound() { |
| Bound::Included(ref k) => match self.lookup_index_for(k) { |
| Ok(index) => index + 1, |
| Err(index) => index, |
| }, |
| Bound::Excluded(ref k) => match self.lookup_index_for(k) { |
| Ok(index) | Err(index) => index, |
| }, |
| Bound::Unbounded => self.data.len(), |
| }; |

I don't see any way check_range could be defined that would help here.