Merging upstream version 127.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/third_party/rust/indexmap/src/util.rs b/third_party/rust/indexmap/src/util.rs
index a24dfafde7..377ff516f0 100644
--- a/third_party/rust/indexmap/src/util.rs
+++ b/third_party/rust/indexmap/src/util.rs
@@ -29,3 +29,25 @@ where
     }
     start..end
 }
+
+pub(crate) fn try_simplify_range<R>(range: R, len: usize) -> Option<Range<usize>>
+where
+    R: RangeBounds<usize>,
+{
+    let start = match range.start_bound() {
+        Bound::Unbounded => 0,
+        Bound::Included(&i) if i <= len => i,
+        Bound::Excluded(&i) if i < len => i + 1,
+        _ => return None,
+    };
+    let end = match range.end_bound() {
+        Bound::Unbounded => len,
+        Bound::Excluded(&i) if i <= len => i,
+        Bound::Included(&i) if i < len => i + 1,
+        _ => return None,
+    };
+    if start > end {
+        return None;
+    }
+    Some(start..end)
+}