Module#parent is deprecated in Rails 6 and will be removed in Rails 6.1

[aar0nr]

Module#parent is deprecated and has been renamed to Module#module_parent in Rails 6.

https://github.com/rails/rails/blob/v6.0.0.rc1/activesupport/lib/active_support/core_ext/module/introspection.rb#L46

def parent
  ActiveSupport::Deprecation.warn(<<-MSG.squish)
    `Module#parent` has been renamed to `module_parent`.
    `parent` is deprecated and will be removed in Rails 6.1.
  MSG
  module_parent
end

Used here:

https://github.com/ClosureTree/closure_tree/blob/master/lib/closure_tree/support.rb#L35