fails:Array#pack with format 'M' encodes a recursive array
fails:Array#pack with format 'M' calls #to_s to convert an object to a String
fails:Array#pack with format 'M' converts the object to a String representation if #to_s does not return a String
fails:Array#pack with format 'M' encodes a Symbol as a String
fails:Array#pack with format 'M' encodes an Integer as a String
fails:Array#pack with format 'm' raises a TypeError if passed an Integer
