Move FL_SINGLETON to FL_USER1

This frees FL_USER0 on both T_MODULE and T_CLASS.

Note: prior to this, FL_SINGLETON was never set on T_MODULE,
so checking for `FL_SINGLETON` without first checking that
`FL_TYPE` was `T_CLASS` was valid. That's no longer the case.

1 files changed, 1 insertions, 1 deletions

diff --git a/marshal.c b/marshal.c
index dabbdcd663..251626f09e 100644
--- a/marshal.c
+++ b/marshal.c
@@ -533,7 +533,7 @@ hash_each(VALUE key, VALUE value, VALUE v)
 static void
 w_extended(VALUE klass, struct dump_arg *arg, int check)
 {
-    if (check && FL_TEST(klass, FL_SINGLETON)) {
+    if (check && RCLASS_SINGLETON_P(klass)) {
         VALUE origin = RCLASS_ORIGIN(klass);
         if (SINGLETON_DUMP_UNABLE_P(klass) ||
             (origin != klass && SINGLETON_DUMP_UNABLE_P(origin))) {