VM implementation scratch space about artichoke HOT 3 OPEN

[2.6.3] > BasicObject.class
=> Class
[2.6.3] > Object.class
=> Class
[2.6.3] > Module.class
=> Class
[2.6.3] > Class.class
=> Class
[2.6.3] > Kernel.class
=> Module
[2.6.3] > Class.ancestors
=> [Class, Module, Object, Kernel, BasicObject]

[2.6.3] > module A; class B; end; end
=> nil
[2.6.3] > inst = A::B.new
=> #<A::B:0x00007fe939a08460>
[2.6.3] > inst.class
=> A::B
[2.6.3] > Object.send(:remove_const, :A)
=> A
[2.6.3] > inst.class
=> A::B
[2.6.3] > inst.class.name
=> "A::B"

$ irb
[3.0.1] > h = { a: "a", b: "b", c: "c" }
=> {:a=>"a", :b=>"b", :c=>"c"}
[3.0.1] > del = true
=> true
[3.0.1] > h.each_value { |v| puts v ; h.delete(:a) if del ; ins = true if del ; del = false ; h[:a] = "aaa" if ins }
a
(irb):3:in `block in <main>': can't add a new key into hash during iteration (RuntimeError)
        from (irb):3:in `each_value'
        from (irb):3:in `<main>'
        from /usr/local/var/rbenv/versions/3.0.1/lib/ruby/gems/3.0.0/gems/irb-1.3.5/exe/irb:11:in `<top (required)>'
        from /usr/local/var/rbenv/versions/3.0.1/bin/irb:23:in `load'
        from /usr/local/var/rbenv/versions/3.0.1/bin/irb:23:in `<main>'
[3.0.1] > h.each_key { |v| puts v ; h.delete(:a) if del ; ins = true if del ; del = false ; h[:a] = "aaa" if ins }
b
c
=> {:b=>"b", :c=>"c"}
[3.0.1] > h = { a: "a", b: "b", c: "c" }
=> {:a=>"a", :b=>"b", :c=>"c"}
[3.0.1] > del = true
=> true
[3.0.1] > h.each_key { |v| puts v ; h.delete(:a) if del ; ins = true if del ; del = false ; h[:a] = "aaa" if ins }
a
(irb):7:in `block in <main>': can't add a new key into hash during iteration (RuntimeError)
        from (irb):7:in `each_key'
        from (irb):7:in `<main>'
        from /usr/local/var/rbenv/versions/3.0.1/lib/ruby/gems/3.0.0/gems/irb-1.3.5/exe/irb:11:in `<top (required)>'
        from /usr/local/var/rbenv/versions/3.0.1/bin/irb:23:in `load'
        from /usr/local/var/rbenv/versions/3.0.1/bin/irb:23:in `<main>'
[3.0.1] > h = { a: "a", b: "b", c: "c" }
=> {:a=>"a", :b=>"b", :c=>"c"}
[3.0.1] > del = true
=> true
[3.0.1] > h.each_key { |v| puts v ; h.delete(:b) if del ; ins = true if del ; del = false }
a
c
=> {:a=>"a", :c=>"c"}