Which Ruby classes support .clone?

Question

Ruby defines #clone in Object. To my suprise, some classes raise Exceptions when calling it. I found NilClass, TrueCla

Answer 1

Rails appears to extend the classes you mention with a "duplicable?()" method.

http://api.rubyonrails.org/files/activesupport/lib/active_support/core_ext/object/duplicable_rb.html