module RSpec::Core::Metadata::GroupMetadataHash

def described_class
  warn_about_first_description_arg_behavioral_change_in_rspec_3
  value_for_rspec_2 = described_class_for_rspec_2
  value_for_rspec_3 = described_class_for_rspec_3
  if value_for_rspec_2 != value_for_rspec_3
    RSpec.warn_deprecation(<<-EOS.gsub(/^\s+\|/, ''))
      |The semantics of `described_class` in a nested `describe <SomeClass>`
      |example group are changing in RSpec 3. In RSpec 2.x, `described_class`
      |would return the outermost described class (#{value_for_rspec_2.inspect}).
      |In RSpec 3, it will return the innermost described class (#{value_for_rspec_3.inspect}).
      |In general, we recommend not describing multiple classes or objects in a
      |nested manner as it creates confusion.
      |
      |To make your code compatible with RSpec 3, change from `described_class` to a reference
      |to `#{value_for_rspec_3.inspect}`, or change the arg of the inner `describe` to a string.
      |(Called from #{CallerFilter.first_non_rspec_line})
    EOS
  end
  value_for_rspec_2
end