Hi Ian, Axel (Glad to see you here;-)
Thank you for your quick explanation. However, I would like to point out that selector rule 3 states: 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), then x.f is shorthand for (**x).f.* The emphasis here is on "defined pointer type." In the code, *s is a composite pointer literal type, not a defined pointer type. Therefore, I believe this rule does not apply in this case. Furthermore, in selector rule 1, it only states that "x.f denotes the field or method." The term "denotes" is somewhat ambiguous and does not imply implicit pointer indirection. 在2024年7月17日星期三 UTC+8 12:51:48<Ian Lance Taylor> 写道： > On Tue, Jul 16, 2024 at 9:29 PM 王旭东 <wxd...@gmail.com> wrote: > > > > Hi, I have a question about "addressable." > > > > The following code illustrates my question (see the comments): > > https://go.dev/play/p/xpiPXuEqh0O?v=gotip > > > > > > > > I also posted question in the Gopher Slack channel, and @Axel Wagner > provided a detailed explanation, suggesting that this might be a gap in the > Go specification. > > @Jason Phillips recommended that I ask this question in the GitHub > issues and the golang-nuts mailing list. > > > > I really appreciate everyone’s help mentioned, but I still don’t have a > clear conclusion. > > > > To simplify: my question is why the result of myfunReturnPointer() is > addressable if we strictly follow the specification. > > > In https://go.dev/ref/spec#Selectors the spec explains that if the > type of x is a pointer, then the selector expression x.f is shorthand > for (*x).f. That is the case in your playground example: the > expression myfunReturnPointer().i is short for > (*myfunReturnPointer()).i. The pointer indirection > *myfunReturnPointer() is addressable according to > https://go.dev/ref/spec#Address_operators. So this is a field > selector of an addressable struct operand. > > Ian > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/0fb5aa3e-4568-4520-bd42-ff01c1a2bd54n%40googlegroups.com.
