Support obj.clone(freeze: true) for freezing clone

This freezes the clone even if the receiver is not frozen.  It
is only for consistency with freeze: false not freezing the clone
even if the receiver is frozen.

Because Object#clone is now partially implemented in Ruby and
not fully implemented in C, freeze: nil must be supported to
provide the default behavior of only freezing the clone if the
receiver is frozen.

This requires modifying delegate and set, to set freeze: nil
instead of freeze: true as the keyword parameter for
initialize_clone.  Those are the two libraries in stdlib that
override initialize_clone.

Implements [Feature #16175]

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/set.rb b/lib/set.rb
index 684115539b..b8ab6ab172 100644
--- a/lib/set.rb
+++ b/lib/set.rb
@@ -137,7 +137,7 @@ class Set
   end
 
   # Clone internal hash.
-  def initialize_clone(orig, freeze: true)
+  def initialize_clone(orig, freeze: nil)
     super
     @hash = orig.instance_variable_get(:@hash).clone(freeze: freeze)
   end