SortedSet remove at index does not work

[pnewell]

Removing items from a SortedSet by index does remove the item, but does not update the count correctly.

Information

• Package version: main
• Platform version: macOS 15.3
• Swift version: 6.0.3

Checklist

• If possible, I've reproduced the issue using the main branch of this package.
• I've searched for existing GitHub issues.

Steps to Reproduce

let set = Set(0 ..< 40)
var sorted = SortedSet(set)
print(sorted.count)
print(sorted.remove(at: sorted.startIndex))
print(sorted)
print(sorted.count)

Expected behavior

40
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39]
0
39

Actual behavior

40
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39]
0
40

[pnewell]

Been playing around with this more, it ultimately leads to a runtime error the next time it checks its count. An easy way to see that is to convert to an array after the remove.