class RuboCop::Cop::RSpec::OverwritingSetup

def find_duplicates(node)
  setup_expressions = Set.new
  node.each_child_node(:block) do |child|
    next unless common_setup?(child)
    name = if child.send_node.arguments?
             first_argument_name(child.send_node).to_sym
           else
             :subject
           end
    yield child, name unless setup_expressions.add?(name)
  end
end