diff --git a/src/formatting.rs b/src/formatting.rs
index 6a4640b..c1853da 100644
--- a/src/formatting.rs
+++ b/src/formatting.rs
@@ -40,10 +40,7 @@ impl StrExt for str {
             .iter()
             .filter_map(|delimiter| self.rfind(delimiter).map(|i| (delimiter, i)))
             .max_by_key(|(_, i)| *i)
-            .map(|(delimiter, _)| {
-                let (prefix, suffix) = self.rsplit_once(delimiter).unwrap();
-                (prefix, *delimiter, suffix)
-            })
+            .map(|(delimiter, i)| (&self[..i], *delimiter, &self[i + delimiter.len()..]))
             .unwrap_or(("", "", self))
     }
 }