diff --git a/uniuri.go b/uniuri.go
index 5296a30..596736a 100644
--- a/uniuri.go
+++ b/uniuri.go
@@ -67,4 +67,5 @@ func NewLenChars(length int, chars []byte) string {
 			}
 		}
 	}
+	panic("unreachable")
 }