# File lib/brakeman/processors/lib/call_conversion_helper.rb, line 23
    def join_strings lhs, rhs, original_exp = nil
      if string? lhs and string? rhs
        result = Sexp.new(:str).line(lhs.line)
        result.value = lhs.value + rhs.value

        if result.value.length > 50
          # Avoid gigantic strings
          lhs
        else
          result
        end
      elsif call? lhs and lhs.method == :+ and string? lhs.first_arg and string? rhs
        joined = join_strings lhs.first_arg, rhs
        lhs.first_arg = joined
        lhs
      elsif safe_literal? lhs or safe_literal? rhs
        safe_literal(lhs.line)
      else
        original_exp
      end
    end