diff --git a/grammar.js b/grammar.js
index d687d56..4402212 100644
--- a/grammar.js
+++ b/grammar.js
@@ -93,6 +93,7 @@ module.exports = grammar({
 
     _block_item: $ => choice(
       $.function_definition,
+      alias($._old_style_function_definition, $.function_definition),
       $.linkage_specification,
       $.declaration,
       $._statement,