class RuboCop::AST::ProcessedSource

def lines

possible __END__ and everything that comes after.
Returns the source lines, line break characters removed, excluding a 
def lines
  @lines ||= begin
    all_lines = @buffer.source_lines
    last_token_line = tokens.any? ? tokens.last.line : all_lines.size
    result = []
    all_lines.each_with_index do |line, ix|
      break if ix >= last_token_line && line == '__END__'
      result << line
    end
    result
  end
end