No programatic way to check ability to dup/clone an object
We can't dup a Fixnum, and it's ok. But I'm wondering «why is Fixnum saying it can dup?»
1.respond_to?(:dup) #=> true
Don't you think that the
dup method should be undefined in the class Fixnum?
Currently I can do
class Fixnum; undef :dup; end, but that should be in the core Ruby, isn't it?