diff --git a/mrbgems/mruby-compiler/core/parse.y b/mrbgems/mruby-compiler/core/parse.y
index 7ca2e088f..c5d1e61b1 100644
--- a/mrbgems/mruby-compiler/core/parse.y
+++ b/mrbgems/mruby-compiler/core/parse.y
@@ -1330,7 +1330,7 @@ heredoc_end(parser_state *p)
 
 %}
 
-%define api.pure
+%pure-parser
 %parse-param {parser_state *p}
 %lex-param {parser_state *p}