On Sunday, February 24, 2019 at 9:36:07 PM UTC, rog wrote: > > Foo is declared as a new type, and no methods are declared on that that > type. If you had declared: > > type Foo = *Foo > > it would have been a different matter. >
true. however, i don't want a type alias because that would make it possible to copy f2 by dereferencing the pointer (f3 = *f2). the reason i don't want that is because in my real use case foo contains a pointer to a CGo struct, which has its lifetime managed by a finalizer. i don't want copies of that pointer made, so i thought that i can force pointer-only usage of foo (via Foo) and that'd be that. it's also not possible to declare methods on pointer types (for a reason explained here <https://groups.google.com/d/msg/golang-nuts/qf76N-uDcHA/DTCDNgaF_p4J>, which makes sense), so `func (f Foo) GetBar() { ... }` is a no-go. it still seems to me that Foo.GetBar should resolve to (*foo).GetBar, since Foo -> *foo is unambiguous. why not? > > On Sun, 24 Feb 2019, 10:30 pm , <roj...@gmail.com <javascript:>> wrote: > >> Why can't Go resolve methods declared on the pointer receiver of the >> destination type? >> >> consider: >> >> type foo struct{ >> bar int >> } >> >> type Foo *foo >> >> func (f *foo) GetBar() int { >> return f.bar >> } >> >> func NewFoo(bar int) Foo { >> return &foo{bar: bar} >> } >> >> func main() { >> f1 := &foo{bar: 123} >> fmt.Printf("%d\n", f1.GetBar()) >> f2 := NewFoo(456) >> fmt.Printf("%d\n", f2.GetBar()) >> } >> >> >> (playground link: https://play.golang.org/p/v0f9pYaTJAa ) >> >> it fails to compile with "prog.go:25:23: f2.GetBar undefined (type Foo >> has no field or method GetBar)" but it's not clear to me, why Foo doesn't >> get pointer methods from *foo. >> >> -- >> 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...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > -- 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. For more options, visit https://groups.google.com/d/optout.
