class RuboCop::Cop::Lint::DuplicateRegexpCharacterClassElement

def each_repeated_character_class_element_loc(node)
  node.parsed_tree&.each_expression do |expr|
    next if skip_expression?(expr)
    seen = Set.new
    group_expressions(node, expr.expressions) do |group|
      group_source = group.map(&:to_s).join
      yield source_range(group) if seen.include?(group_source)
      seen << group_source
    end
  end
end