golang类型有一个与之相关的方法集，这决定了它是否实现某个接口
- 类型T方法集包含所有reciver T方法
- 类型*T方法集包含所有receiver T+*T方法
- 匿名嵌入S，则T方法集包含所有receiver S方法
- 匿名嵌入*S，则T方法集包含所有receiver S+*S方法
- 匿名嵌入S或*S，则*T方法集包含所有receiver S+*S方法
package main
import "fmt"
type tester interface {
tVal()
tPtr()
}
type T2 struct {
*S
}
type T1 struct {
S
}
type S struct {
}
func (p *S) tPtr() { fmt.Printf("caller‘s type is: %#T\n", p) }
func (v S) tVal() { fmt.Printf("caller‘s type is: %#T\n", v) }
func main() {
var t tester
s := S{}
//type S include method tVal(receiver S) but not tPtr(receiver *S)
//t = s
//type *S include method tVal and tPtr
t = &s
t.tPtr()
t.tVal()
//type T1 with annonymous S embedded, include method tVal but not tPtr
//d := T1{S{}}
//t = d
//type T2 with annonymous *S embedded, include method tVal and tPtr
d1 := T2{&S{}}
t = d1
t.tPtr()
t.tVal()
//type *T1 with annonymous S embedded, include method tVal and tPtr
d2 := &T1{S{}}
t = d2
t.tPtr()
t.tVal()
//type *T2 with annonymous *S embedded, include method tVal and tPtr
d3 := &T2{&S{}}
t = d3
t.tPtr()
t.tVal()
}
