不能在字段值中将（* struct）用作（* interface）

Question

我有以下代码：// eventloop.gotype Object interface {    ActivateSlot(name string, parameters vector.Vector);}// main.goimport loop "./eventloop"// ...const slotname = "printer"type printer struct {    slot loop.Slot;}func (p *printer) Init() {    p.slot = loop.Slot{slotname, p}; // offending line}func (p *printer) ActivateSlot(name string, parameters vector.Vector) {    fmt.Println("Slot called: ", name); }当我尝试编译时，出现以下错误：jurily@jurily ~/workspace/go $ ./build.shmain.go:23: cannot use p (type *printer) as type *eventloop.Object in field value如果我将有问题的行注释掉，它可以编译并运行良好。这里发生了什么事？我想念什么？