Yet another fail

fail.go

package main
import "fmt"

type R interface {
    A() string
    B() string
}
type C interface {
    R
    Method(string) func(C)string
}

// ---

type B struct {
    m map[string]func(R)string 
}
func(b B) A() string {
    return "A"
}
func(b B) B() string {
    return "B"
}
func(b B) Method(n string) func(C)string {
    return map[string]func(C)string {
        "A" : C.A,
        "B" : C.B,
    }[n]
}


func lookup(c C, n string){
    fmt.Println(c.Method(n)(c))
}
func main() {
  var b B
  lookup(b, "A")
}