英文:
Method sets for T and *T
问题
Golang语言规范中指出：
> 任何其他类型T的方法集由所有接收器类型为T的方法组成。相应指针类型*T的方法集是所有接收器为*T或T的方法的集合（也就是说，它还包含了T的方法集）。
为什么会这样呢？为什么接收器为T的方法属于*T的方法集，但反过来却不成立？
英文:
The Golang language specification states:
> The method set of any other type T consists of all methods with receiver type T. The method set of the corresponding pointer type *T is the set of all methods with receiver *T or T (that is, it also contains the method set of T).
Why is this? Why do the methods receiving T belong to the method set for *T but not vice versa?
答案1
得分: 6
从FAQ中：
> 如果一个接口值包含一个指针*T，方法调用可以通过解引用指针来获取值，但是如果一个接口值包含一个值T，方法调用无法以有用的方式获取指针。
顺便说一下，具有指针接收器的方法可以更改其接收器，就像它可以更改指针参数一样。将非指针接收器作为指针接收器传递（假设这是可能的），允许方法更改它，这是不应该的。
建议为类型的所有方法使用一致的接收器类型，并避免混合使用指针和直接接收器。对于大型类型，建议使用指针接收器。
英文:
From the FAQ:
> If an interface value contains a pointer *T, a method call can obtain a value by dereferencing the pointer, but if an interface value contains a value T, there is no useful way for a method call to obtain a pointer.
By the way, a method with pointer receiver can change its receiver, just like it can change a pointer parameter. Passing a non-pointer receiver as a pointer one (assuming this is possible), allows the method to change it, which should not.
It is recommended to use one consistent receiver type for all methods of a type and avoid mixing pointer and direct receivers. It is also recommended to use pointer receiver for large types.
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