spec: comments on Selector example unclear #49141
Description
What version of Go are you using (go version)?
$ go version The playground uses the latest stable release of Go. The current version is go1.17.2.
Does this issue reproduce with the latest release?
Yes
What operating system and processor architecture are you using (go env)?
go env Output
$ go env
What did you do?
https://golang.org/ref/spec#Selectors
I tried the Selector example.
I ran the Selector example from Go playground.
https://play.golang.org/p/_kaX9_8vKez
func main() {
var t T2
var p *T2
fmt.Println(t.T0) // with t.T0 != nil (should be t.T0 == nil)
fmt.Println(p) // with p != nil (should be p == nil)
//fmt.Println((*p).T0) // (*p).T0 != nil (illegal invalid memory address or nil pointer dereference)
}
What did you expect to see?
type T0 struct {
x int
}
func (*T0) M0()
type T1 struct {
y int
}
func (T1) M1()
type T2 struct {
z int
T1
*T0
}
func (*T2) M2()
type Q *T2
var t T2 // with t.T0 != nil
var p *T2 // with p != nil and (*p).T0 != nil
func main() {
var t T2
var p *T2
fmt.Println(t.T0) // with t.T0 != nil (I expected t.T0 != nil but got nil)
fmt.Println(p) // with p != nil (I expected p != nil but got nil)
//fmt.Println((*p).T0) // (*p).T0 != nil (I expected (*p).T0 != nil but got illegal invalid memory address or nil pointer dereference)
}
What did you see instead?
type T0 struct {
x int
}
func (*T0) M0()
type T1 struct {
y int
}
func (T1) M1()
type T2 struct {
z int
T1
*T0
}
func (*T2) M2()
type Q *T2
var t T2 // with t.T0 == nil
var p *T2 // with p == nil and (*p).T0 == nil
func main() {
var t T2
var p *T2
fmt.Println(t.T0) // with t.T0 != nil (should be t.T0 == nil)
fmt.Println(p) // with p != nil (should be p == nil)
//fmt.Println((*p).T0) // (*p).T0 != nil (illegal invalid memory address or nil pointer dereference)
}