diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/BotImpl.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/BotImpl.kt
index 2fcd52f8c..2efa4d328 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/BotImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/BotImpl.kt
@@ -106,11 +106,9 @@ internal class BotImpl @PublishedApi internal constructor(
     // endregion
 
     // region contacts
-    @UseExperimental(MiraiInternalAPI::class)
-    override val groups: ContactList<Group> = ContactList(MutableContactList())
+    override val groups: ContactList<Group> = ContactList(LockFreeLinkedList())
 
-    @UseExperimental(MiraiInternalAPI::class)
-    override val qqs: ContactList<QQ> = ContactList(MutableContactList())
+    override val qqs: ContactList<QQ> = ContactList(LockFreeLinkedList())
 
     /**
      * 线程安全地获取缓存的 QQ 对象. 若没有对应的缓存, 则会创建一个.
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/ContactList.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/ContactList.kt
index b3aab356c..46ac648d5 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/ContactList.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/ContactList.kt
@@ -12,7 +12,7 @@ import net.mamoe.mirai.utils.joinToString
  */
 @UseExperimental(MiraiInternalAPI::class)
 @Suppress("unused")
-class ContactList<C : Contact>(@PublishedApi internal val delegate: MutableContactList<C>) {
+class ContactList<C : Contact>(@PublishedApi internal val delegate: LockFreeLinkedList<C>) {
     /**
      * ID 列表的字符串表示.
      * 如:
@@ -35,22 +35,14 @@ class ContactList<C : Contact>(@PublishedApi internal val delegate: MutableConta
     override fun toString(): String = delegate.joinToString(separator = ", ", prefix = "ContactList(", postfix = ")")
 }
 
-/**
- * 可修改联系人列表. 只会在内部使用.
- */
-@MiraiInternalAPI
-class MutableContactList<C : Contact> : LockFreeLinkedList<C>() {
-    override fun toString(): String = joinToString(separator = ", ", prefix = "MutableContactList(", postfix = ")")
+operator fun <C : Contact> LockFreeLinkedList<C>.get(id: UInt): C {
+    forEach { if (it.id == id) return it }
+    throw NoSuchElementException()
+}
 
-    operator fun get(id: UInt): C {
-        forEach { if (it.id == id) return it }
-        throw NoSuchElementException()
-    }
+fun <C : Contact> LockFreeLinkedList<C>.getOrNull(id: UInt): C? {
+    forEach { if (it.id == id) return it }
+    return null
+}
 
-    fun getOrNull(id: UInt): C? {
-        forEach { if (it.id == id) return it }
-        return null
-    }
-
-    fun getOrAdd(id: UInt, supplier: () -> C): C = super.filteringGetOrAdd({it.id == id}, supplier)
-}
\ No newline at end of file
+fun <C : Contact> LockFreeLinkedList<C>.getOrAdd(id: UInt, supplier: () -> C): C = filteringGetOrAdd({ it.id == id }, supplier)
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/network/protocol/tim/packet/action/GroupPacket.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/network/protocol/tim/packet/action/GroupPacket.kt
index 3595c197d..2f7b1bcf3 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/network/protocol/tim/packet/action/GroupPacket.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/network/protocol/tim/packet/action/GroupPacket.kt
@@ -10,6 +10,7 @@ import net.mamoe.mirai.message.internal.toPacket
 import net.mamoe.mirai.network.BotNetworkHandler
 import net.mamoe.mirai.network.protocol.tim.TIMProtocol
 import net.mamoe.mirai.network.protocol.tim.packet.*
+import net.mamoe.mirai.utils.LockFreeLinkedList
 import net.mamoe.mirai.utils.MiraiInternalAPI
 import net.mamoe.mirai.utils.io.*
 import net.mamoe.mirai.withSession
@@ -54,7 +55,7 @@ internal data class RawGroupInfo(
     @Suppress("NOTHING_TO_INLINE") // this function it only executed in one place.
     @UseExperimental(MiraiInternalAPI::class)
     inline fun parseBy(group: Group): GroupInfo = group.bot.withSession {
-        val memberList = MutableContactList<Member>()
+        val memberList = LockFreeLinkedList<Member>()
         members.forEach { entry: Map.Entry<UInt, MemberPermission> ->
             entry.key.qq().let { group.Member(it, entry.value, it.coroutineContext) }
         }