# File lib/brakeman/checks/check_sql.rb, line 567
  def string_building? exp
    return false unless call? exp and STRING_METHODS.include? exp.method

    node_type? exp.target, :str, :dstr or
    node_type? exp.first_arg, :str, :dstr or
    string_building? exp.target or
    string_building? exp.first_arg
  end