class RuboCop::Cop::Performance::RedundantSplitRegexpArgument

def replacement(regexp_node)
  regexp_content = regexp_node.content
  stack = []
  chars = regexp_content.chars.each_with_object([]) do |char, strings|
    if stack.empty? && char == '\\'
      stack.push(char)
    else
      strings << "#{stack.pop}#{char}"
    end
  end
  chars.map do |char|
    char = char.dup
    char.delete!('\\') unless STR_SPECIAL_CHARS.include?(char)
    char
  end.join
end