1 files changed, 2 insertions, 0 deletions
diff --git a/parse.y b/parse.y
index 492fd3da64..8d3df90b0a 100644
--- a/parse.y
+++ b/parse.y
@@ -11445,9 +11445,11 @@ ripper_initialize(int argc, VALUE *argv, VALUE self)
     parser->eofp = Qfalse;
     if (NIL_P(fname)) {
         fname = STR_NEW2("(ripper)");
+	OBJ_FREEZE(fname);
     }
     else {
         StringValue(fname);
+	fname = rb_str_new_frozen(fname);
     }
     parser_initialize(parser);