為什麼在 Go 中從鍊錶中刪除元素時應該將指標設為 Nil 以防止記憶體洩漏？

package main

import (
    "fmt"
    "runtime/pprof"
)

type Element struct {
    value       int
    prev, next *Element
}

type List struct {
    head, tail *Element
    length    int
}

func main() {
    f, _ := pprof.CreateProfile("memleak")
    defer f.Stop()

    list := List{}
    e1 := &Element{value: 1}
    e2 := &Element{value: 2}
    e3 := &Element{value: 3}

    // Create a cycle by setting e2 as the next of e1 and the prev of e3.
    e1.next = e2
    e3.prev = e2

    // Add the elements to the list.
    list.PushBack(e1)
    list.PushBack(e2)
    list.PushBack(e3)

    // Remove e2 from the list without setting e1.next and e3.prev to nil.
    list.Remove(e2)

    // Print the elements of the list, which should be [1, 3].
    fmt.Println("List:", list.Values())

    // Check for memory leaks.
    fmt.Println("Memory Profile:", pprof.Lookup("heap").String())
}