class RuboCop::Cop::Style::FormatStringToken

def str_contents(source_map)
  if source_map.is_a?(Parser::Source::Map::Heredoc)
    source_map.heredoc_body
  elsif source_map.begin
    source_map.expression.adjust(begin_pos: +1, end_pos: -1)
  else
    source_map.expression
  end
end