diff --git a/src/lib.rs b/src/lib.rs
index 58dba71..0bf245d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -297,7 +297,7 @@ impl fmt::Display for ParseError {
                 f,
                 "Invalid byte count; Matched `{}` bytes ({:?})",
                 found,
-                &eui[..found]
+                eui
             ),
         }
     }
@@ -745,6 +745,10 @@ mod tests {
             "Err(InvalidByteCount(7, [18, 52, 86, 171, 205, 239]))".to_owned(),
             format!("{:?}", MacAddress::parse_str("123456ABCDEF1"))
         );
+        assert_eq!(
+            "Invalid byte count; Matched `7` bytes ([18, 52, 86, 171, 205, 239])".to_owned(),
+            format!("{}", MacAddress::parse_str("123456ABCDEF1").unwrap_err())
+        );
         assert_eq!(
             "Err(InvalidLength(19))",
             format!("{:?}", MacAddress::parse_str("12##45#67#89#AB#C#D"))