diff --git a/ast.c b/ast.c
index 92542a2e22dcd8..cf7d8a8a44702c 100644
--- a/ast.c
+++ b/ast.c
@@ -131,8 +131,7 @@ rb_ast_parse_file(VALUE path, VALUE keep_script_lines, VALUE error_tolerant, VAL
 static VALUE
 lex_array(struct parser_params *p, rb_parser_input_data data, int index)
 {
-    /* TODO */
-    VALUE array;
+    VALUE array = (VALUE)data;
     VALUE str = rb_ary_entry(array, index);
     if (!NIL_P(str)) {
         StringValue(str);