golang 中的 (&t).value 和 t.value 有什么区别？ t 是一个结构

Question

我在 golang 中有这样一个结构，如下所示：

type test struct {
    value int
}

当我尝试这个时

t := test{1}
fmt.Println((&t).value)
fmt.Println(t.value)

编译器没有报错，和我一样的输出1, 这个输出 confused me.What is different between (&t).value and t.value in golang?

Answer 1

选择器表达式 p.f 其中 p 是指向某个结构类型的指针，而 f 是该结构类型的字段 shorthand for (*p).f.

您的表达式 (&t) 产生指针类型 *test 的值。所以这使得 (&t).value 成为 (*(&t)).value 的 shorthand。

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Selectors:

The following rules apply to selectors:

1. For a value x of type T or *T where T is not a pointer or interface type, x.f denotes the field or method at the shallowest depth in T where there is such an f. If there is not exactly one f with shallowest depth, the selector expression is illegal.
2. For a value x of type I where I is an interface type, x.f denotes the actual method with name f of the dynamic value of x. If there is no method with name f in the method set of I, the selector expression is illegal.
3. As an exception, if the type of x is a defined pointer type and (*x).f is a valid selector expression denoting a field (but not a method), x.f is shorthand for (*x).f.
4. In all other cases, x.f is illegal.
5. If x is of pointer type and has the value nil and x.f denotes a struct field, assigning to or evaluating x.f causes a run-time panic.
6. If x is of interface type and has the value nil, calling or evaluating the method x.f causes a run-time panic.