1 files changed, 1 insertions, 1 deletions
diff --git a/regparse.h b/regparse.h
index 26ebb117e4..cd653f5a8e 100644
--- a/regparse.h
+++ b/regparse.h
@@ -279,7 +279,7 @@ typedef struct {
   OnigOptionType   option;
   OnigCaseFoldType case_fold_flag;
   OnigEncoding     enc;
-  OnigSyntaxType*  syntax;
+  const OnigSyntaxType* syntax;
   BitStatusType    capture_history;
   BitStatusType    bt_mem_start;
   BitStatusType    bt_mem_end;