[ruby/json] Use rb_str_new_frozen

https://github.com/ruby/json/commit/90c8aaaa6a

1 files changed, 1 insertions, 1 deletions

diff --git a/ext/json/generator/generator.c b/ext/json/generator/generator.c
index 362eff7f73..1213f42497 100644
--- a/ext/json/generator/generator.c
+++ b/ext/json/generator/generator.c
@@ -1113,7 +1113,7 @@ static VALUE string_config(VALUE config)
     if (RTEST(config)) {
         Check_Type(config, T_STRING);
         if (RSTRING_LEN(config)) {
-            return RB_OBJ_FROZEN(config) ? config : rb_str_freeze(rb_str_dup(config));
+            return rb_str_new_frozen(config);
         }
     }
     return Qfalse;