Foo
foo(Foo)
a = Foo

::Foo
::Foo::Bar::Baz
Foo::Bar::Baz
Foo::  Bar::
  Baz

Foo::
  # a

  Bar::
  Baz:: # b
  Qux # c

self.class::Foo
a.b(1, 2)[3]::C::D

self
self.foo # foo

$'
$&
$1
$99999

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