Singleton class of frozen object should be frozen

Before this patch:

  p (class << Object.new.freeze; self end).frozen?                #=> false
  sc = class << (o=Object.new); self end; o.freeze; p sc.frozen?  #=> false

After this patch / Ruby:

  p (class << Object.new.freeze; self end).frozen?                #=> true
  sc = class << (o=Object.new); self end; o.freeze; p sc.frozen?  #=> true

1 files changed, 1 insertions, 0 deletions

diff --git a/src/kernel.c b/src/kernel.c
index d9a1d36ce..45bca7558 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -438,6 +438,7 @@ mrb_obj_freeze(mrb_state *mrb, mrb_value self)
     struct RBasic *b = mrb_basic_ptr(self);
     if (!MRB_FROZEN_P(b)) {
       MRB_SET_FROZEN_FLAG(b);
+      if (b->c->tt == MRB_TT_SCLASS) MRB_SET_FROZEN_FLAG(b->c);
     }
   }
   return self;