diff --git a/xo-tokenizer/include/xo/tokenizer/tokenizer.hpp b/xo-tokenizer/include/xo/tokenizer/tokenizer.hpp
index ba340b1a..b9782b10 100644
--- a/xo-tokenizer/include/xo/tokenizer/tokenizer.hpp
+++ b/xo-tokenizer/include/xo/tokenizer/tokenizer.hpp
@@ -213,7 +213,7 @@ namespace xo {
                 }
 
                 /** fall through to numeric literal code below **/
-                ;
+                [[fallthrough]];
             case '.':
             case '0':
             case '1':