message: Property truncate snippet in call stack
  Summary:
  * count chars, not bytes
  * use `...` on long strings
diff: @@ -147,7 +147,7 @@ pub(crate) struct StrIndices<'a> {
  }
  /// Split the string at given char offset. `None` if offset is out of bounds.
  -fn split_at(x: &str, i: CharIndex) -> Option<(&str, &str)> {
  +pub(crate) fn split_at(x: &str, i: CharIndex) -> Option<(&str, &str)> {
  if i.0 == 0 {
  return Some(("", x));
  }
  