Extended Interface not correctly visualized about goplantuml HOT 4 CLOSED

package tmp

type Lock struct {
}

type Buffer interface {
}

type Locker interface {
}

type ReadWriter interface {
	Read(b Buffer) bool
	Write(b Buffer) bool
}

type File interface {
	Buffer // same as adding the methods of ReadWriter
	Locker // same as adding the methods of Locker
	Close()
}

type LockedFile interface {
	Locker
	File   // illegal: Lock, Unlock not unique
	Lock() // illegal: Lock not unique
}

@startuml
namespace tmp {
    class Lock << (S,Aquamarine) >> {
    }
    interface Buffer  {
    }
    interface Locker  {
    }
    interface ReadWriter  {
        + Read(b Buffer) bool
        + Write(b Buffer) bool

    }
    interface File  {
        + Close() 

    }
    interface LockedFile  {
        + Lock() 

    }
}
tmp.Locker *-- tmp.File
tmp.Buffer *-- tmp.File
tmp.Locker *-- tmp.LockedFile
tmp.File *-- tmp.LockedFile


@enduml