点运算符(The Dot Operator)点运算符(The Dot Operator)点运算符将执行很多魔术来转换类型.它将执行自动引用,自动解引用和强制转换,直到类型匹配. TODO:窃取信息自http://stackoverflow.com/questions/28519997/what-are-rusts-exact-auto-dereferencing-rules/28552082#28552082