cmd/go2go: instantiate generic redeclared in this block

[kylelemons]

What version of Go are you using (go version)?

go2goplay.golang.org

What did you do?

https://go2goplay.golang.org/p/s37l9l0m7Du

type End struct{}

type Dimension(type P) struct {
	Name   string
	Parent P
}

func Dim(type Parent)(name string, p Parent) Dimension(Parent) {
	return Dimension(Parent){
		Name:   name,
		Parent: p,
	}
}

func main() {
	d := Dim("a", Dim("b", Dim("c", End{})))
	fmt.Printf("%T", d)
}

What did you expect to see?

Something like Dim(Dim(Dim(End))) except mangled as successful output

What did you see instead?

The following error:

./prog.go2:23: instantiate୦୦Dimension୦main୮aEnd redeclared in this block
	previous declaration at ./prog.go2:28
./prog.go2:21: cannot use p (type instantiate୦୦Dimension୦main୮aEnd) as type instantiate୦୦Dimension୦main୮aEnd in field value

This is either an incorrect error (if the code should be fine) or an error message that I am unable to interpret to be able to figure out what I did wrong.

[kylelemons]

It seems to work fine with one and two levels of nesting, but not three.

[andybons]

@griesemer @ianlancetaylor

[griesemer]

This looks like a bug in the translator part (type checking is fine).

[gopherbot]

Change https://golang.org/cl/238618 mentions this issue: [dev.go2go] go/go2go: make uses of typeInstantiations consistent

[ianlancetaylor]

Thanks, this should be fixed now.