Redesign Message.Key. #693.

- `ConstrainSingle` now extends a more general type `SingleMessage` instead of `MessageMetadata` for extendability
- `Message.Key` moved to `ConstrainSingle.Key`
- Delete `companion object Key`s from duplicable messages

mirai-core-api/src/commonMain/kotlin/message/data/At.kt

@@ -52,10 +52,7 @@ private constructor(
     public override fun toString(): String = "[mirai:at:$target,$display]"
     public override fun contentToString(): String = this.display
 
-    public companion object Key : Message.Key<At> {
+    public companion object {
-        public override val typeName: String
-            get() = "At"
-
         /**
          * 构造一个 [At], 仅供内部使用, 否则可能造成消息无法发出的问题.
          */

mirai-core-api/src/commonMain/kotlin/message/data/AtAll.kt

@@ -30,11 +30,8 @@ private const val displayA = "@全体成员"
  */
 @Serializable
 public object AtAll :
-    Message.Key<AtAll>,
     MessageContent, CodableMessage {
     public const val display: String = displayA
-    public override val typeName: String
-        get() = "AtAll"
 
     @Suppress("SpellCheckingInspection")
     public override fun toString(): String = "[mirai:atall]"

mirai-core-api/src/commonMain/kotlin/message/data/CustomMessage.kt

@@ -60,7 +60,7 @@ public sealed class CustomMessage : SingleMessage {
          * 应确保唯一且不变.
          */
         public final override val typeName: String
-    ) : Message.Key<M> {
+    ) : ConstrainSingle.Key<M> {
 
         init {
             @Suppress("LeakingThis")
@@ -114,8 +114,7 @@ public sealed class CustomMessage : SingleMessage {
         public override fun load(input: ByteArray): M = json.decodeFromString(serializer(), String(input))
     }
 
-    public companion object Key : Message.Key<CustomMessage> {
+    public companion object {
-        override val typeName: String get() = "CustomMessage"
         private val factories: LockFreeLinkedList<Factory<*>> = LockFreeLinkedList()
 
         internal fun register(factory: Factory<out CustomMessage>) {
@@ -196,14 +195,12 @@ public fun <T : CustomMessage> T.toByteArray(): ByteArray {
 @Serializable
 @MiraiExperimentalApi
 public abstract class CustomMessageMetadata : CustomMessage(), MessageMetadata {
-    public companion object Key : Message.Key<CustomMessageMetadata> {
-        override val typeName: String get() = "CustomMessageMetadata"
-    }
-
     public open fun customToString(): ByteArray = customToStringImpl(this.getFactory())
 
     final override fun toString(): String =
         "[mirai:custom:${getFactory().typeName}:${String(customToString())}]"
+
+    public companion object
 }
 
 

mirai-core-api/src/commonMain/kotlin/message/data/Face.kt

@@ -27,8 +27,7 @@ public data class Face(public val id: Int) : // used in delegation
 
     public override fun toString(): String = "[mirai:face:$id]"
     public override fun contentToString(): String =
-        if (id >= 0 && id <= 255)
+        if (id in 0..255) FaceName.names[id]
-            FaceName.names[id]
         else "[表情]"
 
     public override fun equals(other: Any?): Boolean = other is Face && other.id == this.id
@@ -38,10 +37,7 @@ public data class Face(public val id: Int) : // used in delegation
      * @author LamGC
      */
     @Suppress("SpellCheckingInspection", "unused")
-    public companion object IdList : Message.Key<Face> {
+    public companion object {
-        public override val typeName: String
-            get() = "Face"
-
         public const val unknown: Int = 0xff
         public const val jingya: Int = 0
         public const val piezui: Int = 1

mirai-core-api/src/commonMain/kotlin/message/data/ForwardMessage.kt

@@ -174,9 +174,7 @@ public data class ForwardMessage(
         public val message: Message
     }
 
-    public companion object Key : Message.Key<ForwardMessage> {
+    public companion object
-        public override val typeName: String get() = "ForwardMessage"
-    }
 }
 
 

mirai-core-api/src/commonMain/kotlin/message/data/HummerMessage.kt

@@ -16,7 +16,6 @@ package net.mamoe.mirai.message.data
 import kotlinx.serialization.Contextual
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.message.code.CodableMessage
-import net.mamoe.mirai.message.data.PokeMessage.Types
 import net.mamoe.mirai.message.data.VipFace.Companion
 import net.mamoe.mirai.message.data.VipFace.Kind
 
@@ -28,10 +27,7 @@ import net.mamoe.mirai.message.data.VipFace.Kind
  */
 @Serializable
 public sealed class HummerMessage : MessageContent {
-    public companion object Key : Message.Key<HummerMessage> {
+    public companion object
-        public override val typeName: String
-            get() = "HummerMessage"
-    }
     // has service type etc.
 }
 
@@ -45,7 +41,7 @@ public sealed class HummerMessage : MessageContent {
  * ## mirai 码支持
  * 格式: &#91;mirai:poke:*[name]*,*[type]*,*[id]*&#93;
  *
- * @see Types 使用伴生对象中的常量
+ * @see PokeMessage.Companion 使用伴生对象中的常量
  */
 @Serializable
 public data class PokeMessage internal constructor(
@@ -58,10 +54,7 @@ public data class PokeMessage internal constructor(
     public val id: Int
 ) : HummerMessage(), CodableMessage {
     @Suppress("DEPRECATION_ERROR", "DEPRECATION", "INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
-    public companion object Types : Message.Key<PokeMessage> {
+    public companion object {
-        public override val typeName: String
-            get() = "PokeMessage"
-
         /** 戳一戳 */
         @JvmField
         public val Poke: PokeMessage = PokeMessage("戳一戳", 1, -1)
@@ -182,9 +175,7 @@ public data class VipFace internal constructor(
     }
 
     @Suppress("DEPRECATION_ERROR", "DEPRECATION", "INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
-    public companion object : Message.Key<VipFace> {
+    public companion object {
-        override val typeName: String get() = "VipFace"
-
         @JvmStatic
         public val LiuLian: Kind = 9 to "榴莲"
 
@@ -254,8 +245,12 @@ public data class VipFace internal constructor(
  * @see Image 查看图片相关信息
  */
 @Serializable
-public sealed class FlashImage : MessageContent, HummerMessage(), CodableMessage {
+public sealed class FlashImage : MessageContent, HummerMessage(), CodableMessage, ConstrainSingle<FlashImage> {
-    public companion object Key : Message.Key<FlashImage> {
+    override val key: ConstrainSingle.Key<FlashImage> get() = Key
+
+    public companion object Key : ConstrainSingle.Key<FlashImage> {
+        override val typeName: String get() = "FlashImage"
+
         /**
          * 将普通图片转换为闪照.
          */
@@ -280,9 +275,6 @@ public sealed class FlashImage : MessageContent, HummerMessage(), CodableMessage
         public operator fun invoke(imageId: String): FlashImage {
             return invoke(Image(imageId))
         }
-
-        public override val typeName: String
-            get() = "FlashImage"
     }
 
     /**
@@ -315,7 +307,7 @@ public inline fun FriendImage.flash(): FriendFlashImage = FlashImage(this) as Fr
  */
 @Serializable
 public data class GroupFlashImage(@Contextual override val image: GroupImage) : FlashImage() {
-    public companion object Key : Message.Key<GroupFlashImage> {
+    public companion object Key : ConstrainSingle.Key<GroupFlashImage> {
         public override val typeName: String get() = "GroupFlashImage"
     }
 }
@@ -325,7 +317,7 @@ public data class GroupFlashImage(@Contextual override val image: GroupImage) :
  */
 @Serializable
 public data class FriendFlashImage(@Contextual override val image: FriendImage) : FlashImage() {
-    public companion object Key : Message.Key<FriendFlashImage> {
+    public companion object Key : ConstrainSingle.Key<FriendFlashImage> {
         public override val typeName: String get() = "FriendFlashImage"
     }
 }

mirai-core-api/src/commonMain/kotlin/message/data/Image.kt

@@ -109,9 +109,7 @@ public interface Image : Message, MessageContent, CodableMessage {
         }
     }
 
-    public companion object : Message.Key<Image> {
+    public companion object {
-        override val typeName: String get() = "Image"
-
         /**
          * 通过 [Image.imageId] 构造一个 [Image] 以便发送.
          * 这个图片必须是服务器已经存在的图片.
@@ -189,9 +187,7 @@ public val Image.md5: ByteArray
 // NotOnlineImage
 public abstract class FriendImage @MiraiInternalApi public constructor() :
     AbstractImage() { // change to sealed in the future.
-    public companion object Key : Message.Key<FriendImage> {
+    public companion object
-        public override val typeName: String get() = "FriendImage"
-    }
 }
 
 /**
@@ -203,9 +199,7 @@ public abstract class FriendImage @MiraiInternalApi public constructor() :
 // CustomFace
 public abstract class GroupImage @MiraiInternalApi public constructor() :
     AbstractImage() { // change to sealed in the future.
-    public companion object Key : Message.Key<GroupImage> {
+    public companion object
-        public override val typeName: String get() = "GroupImage"
-    }
 }
 
 /**

mirai-core-api/src/commonMain/kotlin/message/data/Message.kt

@@ -27,9 +27,10 @@ import net.mamoe.mirai.message.MessageEvent
 import net.mamoe.mirai.message.MessageReceipt
 import net.mamoe.mirai.message.MessageSerializer
 import net.mamoe.mirai.message.MessageSerializerImpl
-import net.mamoe.mirai.message.data.Message.Key
+import net.mamoe.mirai.message.data.ConstrainSingle.Key
 import net.mamoe.mirai.utils.MiraiExperimentalApi
 import kotlin.contracts.contract
+import kotlin.reflect.KClass
 
 /**
  * 可发送的或从服务器接收的消息.
@@ -78,23 +79,6 @@ import kotlin.contracts.contract
  */
 @Serializable(Message.Serializer::class)
 public interface Message { // must be interface. Don't consider any changes.
-    /**
-     * 类型 Key. 由伴生对象实现, 表示一个 [Message] 对象的类型.
-     *
-     * 除 [MessageChain] 外, 每个 [Message] 类型都拥有一个`伴生对象`(companion object) 来持有一个 Key
-     * 在 [MessageChain.get] 时将会使用到这个 Key 进行判断类型.
-     *
-     * #### 用例
-     * [MessageChain.get]: 允许使用数组访问操作符获取指定类型的消息元素 ```val image: Image = chain[Image]```
-     *
-     * @param M 指代持有这个 Key 的消息类型
-     */
-    public interface Key<out M : Message> {
-        /**
-         * 此 [Key] 指代的 [Message] 类型名. 一般为 `class.simpleName`, 如 "QuoteReply", "PlainText"
-         */
-        public val typeName: String
-    }
 
     /**
      * 将 `this` 和 [tail] 连接.
@@ -311,12 +295,36 @@ public interface MessageMetadata : SingleMessage {
  *
  * 实现此接口的元素将会在连接时自动处理替换.
  */
-public interface ConstrainSingle<out M : Message> : MessageMetadata {
+public interface ConstrainSingle<out M : Message> : SingleMessage {
     /**
      * 用于判断是否为同一种元素的 [Key]
      * @see Key 查看更多信息
      */
     public val key: Key<M>
+
+    /**
+     * 类型 Key. 由伴生对象实现, 表示一个 [Message] 对象的类型.
+     *
+     * 除 [MessageChain] 外, 每个 [Message] 类型都拥有一个伴生对象 (companion object) 来持有一个 Key
+     *
+     * 在 [MessageChain.get] 时将会使用到这个 Key 进行判断类型.
+     *
+     * #### 用例
+     * [MessageChain.get][MessageChain.get]: 允许使用数组访问操作符获取指定类型的消息元素
+     * ```
+     * val image: Image = chain[Image]
+     * ```
+     *
+     * @param M 指代持有这个 Key 的消息类型
+     */
+    public interface Key<out M : Message> {
+        /**
+         * 此 [Key] 指代的 [Message] 类型名. 一般为 [KClass.simpleName], 如 "QuoteReply", "PlainText"
+         *
+         * 仅用于提示作用.
+         */
+        public val typeName: String
+    }
 }
 
 /**

mirai-core-api/src/commonMain/kotlin/message/data/MessageChain.kt

@@ -83,7 +83,7 @@ public interface MessageChain : Message, List<SingleMessage>, RandomAccess {
      * @see MessageChain.getOrFail 在找不到此类型的元素时抛出 [NoSuchElementException]
      */
     @JvmName("first")
-    public operator fun <M : Message> get(key: Message.Key<M>): M? = firstOrNull(key)
+    public operator fun <M : Message> get(key: ConstrainSingle.Key<M>): M? = firstOrNull(key)
 
     public object Serializer : KSerializer<MessageChain> {
         private val delegate = ListSerializer(Message.Serializer)
@@ -102,8 +102,8 @@ public interface MessageChain : Message, List<SingleMessage>, RandomAccess {
  */
 @JvmOverloads
 public inline fun <M : Message> MessageChain.getOrFail(
-    key: Message.Key<M>,
+    key: ConstrainSingle.Key<M>,
-    crossinline lazyMessage: (key: Message.Key<M>) -> String = { key.typeName }
+    crossinline lazyMessage: (key: ConstrainSingle.Key<M>) -> String = { key.typeName }
 ): M = firstOrNull(key) ?: throw NoSuchElementException(lazyMessage(key))
 
 
@@ -174,7 +174,7 @@ public inline fun <reified M : Message> MessageChain.anyIsInstance(): Boolean =
  */
 @JvmSynthetic
 @Suppress("UNCHECKED_CAST")
-public fun <M : Message> MessageChain.firstOrNull(key: Message.Key<M>): M? = firstOrNullImpl(key)
+public fun <M : Message> MessageChain.firstOrNull(key: ConstrainSingle.Key<M>): M? = firstOrNullImpl(key)
 
 /**
  * 获取第一个 [M] 类型的 [Message] 实例
@@ -182,7 +182,7 @@ public fun <M : Message> MessageChain.firstOrNull(key: Message.Key<M>): M? = fir
  */
 @JvmSynthetic
 @Suppress("UNCHECKED_CAST")
-public inline fun <M : Message> MessageChain.first(key: Message.Key<M>): M =
+public inline fun <M : Message> MessageChain.first(key: ConstrainSingle.Key<M>): M =
     firstOrNull(key) ?: throw NoSuchElementException("Message type ${key.typeName} not found in chain $this")
 
 /**
@@ -190,7 +190,7 @@ public inline fun <M : Message> MessageChain.first(key: Message.Key<M>): M =
  */
 @JvmSynthetic
 @Suppress("UNCHECKED_CAST")
-public inline fun <M : Message> MessageChain.any(key: Message.Key<M>): Boolean = firstOrNull(key) != null
+public inline fun <M : Message> MessageChain.any(key: ConstrainSingle.Key<M>): Boolean = firstOrNull(key) != null
 
 // endregion accessors
 

mirai-core-api/src/commonMain/kotlin/message/data/MessageSource.kt

@@ -63,7 +63,7 @@ import net.mamoe.mirai.utils.LazyProperty
  */
 @Serializable(MessageSourceSerializer::class)
 public sealed class MessageSource : Message, MessageMetadata, ConstrainSingle<MessageSource> {
-    public final override val key: Message.Key<MessageSource> get() = Key
+    public final override val key: ConstrainSingle.Key<MessageSource> get() = Key
 
     /**
      * 所属 [Bot.id]
@@ -132,7 +132,7 @@ public sealed class MessageSource : Message, MessageMetadata, ConstrainSingle<Me
      */
     public final override fun toString(): String = "[mirai:source:$ids,$internalIds]"
 
-    public companion object Key : Message.Key<MessageSource> {
+    public companion object Key : ConstrainSingle.Key<MessageSource> {
         override val typeName: String get() = "MessageSource"
 
         /**
@@ -258,7 +258,7 @@ public inline val MessageSource.botOrNull: Bot?
  * @see OnlineMessageSource.toOffline 转为 [OfflineMessageSource]
  */
 public sealed class OnlineMessageSource : MessageSource() {
-    public companion object Key : Message.Key<OnlineMessageSource> {
+    public companion object Key : ConstrainSingle.Key<OnlineMessageSource> {
         public override val typeName: String get() = "OnlineMessageSource"
     }
 
@@ -294,7 +294,7 @@ public sealed class OnlineMessageSource : MessageSource() {
      * 由 [机器人主动发送消息][Contact.sendMessage] 产生的 [MessageSource], 可通过 [MessageReceipt] 获得.
      */
     public sealed class Outgoing : OnlineMessageSource() {
-        public companion object Key : Message.Key<Outgoing> {
+        public companion object Key : ConstrainSingle.Key<Outgoing> {
             public override val typeName: String get() = "OnlineMessageSource.Outgoing"
         }
 
@@ -305,7 +305,7 @@ public sealed class OnlineMessageSource : MessageSource() {
         public final override val targetId: Long get() = target.id
 
         public abstract class ToFriend : Outgoing() {
-            public companion object Key : Message.Key<ToFriend> {
+            public companion object Key : ConstrainSingle.Key<ToFriend> {
                 public override val typeName: String get() = "OnlineMessageSource.Outgoing.ToFriend"
             }
 
@@ -315,7 +315,7 @@ public sealed class OnlineMessageSource : MessageSource() {
         }
 
         public abstract class ToTemp : Outgoing() {
-            public companion object Key : Message.Key<ToTemp> {
+            public companion object Key : ConstrainSingle.Key<ToTemp> {
                 public override val typeName: String get() = "OnlineMessageSource.Outgoing.ToTemp"
             }
 
@@ -325,7 +325,7 @@ public sealed class OnlineMessageSource : MessageSource() {
         }
 
         public abstract class ToGroup : Outgoing() {
-            public companion object Key : Message.Key<ToGroup> {
+            public companion object Key : ConstrainSingle.Key<ToGroup> {
                 public override val typeName: String get() = "OnlineMessageSource.Outgoing.ToGroup"
             }
 
@@ -338,7 +338,7 @@ public sealed class OnlineMessageSource : MessageSource() {
      * 接收到的一条消息的 [MessageSource]
      */
     public sealed class Incoming : OnlineMessageSource() {
-        public companion object Key : Message.Key<Incoming> {
+        public companion object Key : ConstrainSingle.Key<Incoming> {
             public override val typeName: String get() = "OnlineMessageSource.Incoming"
         }
 
@@ -348,7 +348,7 @@ public sealed class OnlineMessageSource : MessageSource() {
         public final override val targetId: Long get() = target.id
 
         public abstract class FromFriend : Incoming() {
-            public companion object Key : Message.Key<FromFriend> {
+            public companion object Key : ConstrainSingle.Key<FromFriend> {
                 public override val typeName: String get() = "OnlineMessageSource.Incoming.FromFriend"
             }
 
@@ -359,7 +359,7 @@ public sealed class OnlineMessageSource : MessageSource() {
         }
 
         public abstract class FromTemp : Incoming() {
-            public companion object Key : Message.Key<FromTemp> {
+            public companion object Key : ConstrainSingle.Key<FromTemp> {
                 public override val typeName: String get() = "OnlineMessageSource.Incoming.FromTemp"
             }
 
@@ -370,7 +370,7 @@ public sealed class OnlineMessageSource : MessageSource() {
         }
 
         public abstract class FromGroup : Incoming() {
-            public companion object Key : Message.Key<FromGroup> {
+            public companion object Key : ConstrainSingle.Key<FromGroup> {
                 public override val typeName: String get() = "OnlineMessageSource.Incoming.FromGroup"
             }
 
@@ -389,7 +389,7 @@ public sealed class OnlineMessageSource : MessageSource() {
  * @see buildMessageSource 构建一个 [OfflineMessageSource]
  */
 public abstract class OfflineMessageSource : MessageSource() {
-    public companion object Key : Message.Key<OfflineMessageSource> {
+    public companion object Key : ConstrainSingle.Key<OfflineMessageSource> {
         public override val typeName: String get() = "OfflineMessageSource"
     }
 

mirai-core-api/src/commonMain/kotlin/message/data/PlainText.kt

@@ -30,9 +30,7 @@ public data class PlainText(
     public override fun toString(): String = content
     public override fun contentToString(): String = content
 
-    public companion object Key : Message.Key<PlainText> {
+    public companion object
-        public override val typeName: String get() = "PlainText"
-    }
 }
 
 /**

mirai-core-api/src/commonMain/kotlin/message/data/QuoteReply.kt

@@ -40,12 +40,12 @@ import net.mamoe.mirai.message.data.MessageSource.Key.recall
  */
 @Serializable
 public data class QuoteReply(public val source: MessageSource) : Message, MessageMetadata, ConstrainSingle<QuoteReply> {
-    public companion object Key : Message.Key<QuoteReply> {
+    public companion object Key : ConstrainSingle.Key<QuoteReply> {
         public override val typeName: String
             get() = "QuoteReply"
     }
 
-    public override val key: Message.Key<QuoteReply> get() = Key
+    public override val key: ConstrainSingle.Key<QuoteReply> get() = Key
 
     // TODO: 2020/12/2 QuoteReply.toString
     public override fun toString(): String = "[mirai:quote:${source.ids},${source.internalIds}]"

mirai-core-api/src/commonMain/kotlin/message/data/RichMessage.kt

@@ -45,7 +45,7 @@ public interface RichMessage : MessageContent {
      * @suppress 此 API 不稳定, 可能在任意时刻被删除
      */
     @MiraiExperimentalApi
-    public companion object Templates : Message.Key<RichMessage> {
+    public companion object Templates : ConstrainSingle.Key<RichMessage> {
 
         /**
          * @suppress 此 API 不稳定, 可能在任意时刻被删除
@@ -93,7 +93,7 @@ public interface RichMessage : MessageContent {
  */
 @Serializable
 public data class LightApp(override val content: String) : RichMessage {
-    public companion object Key : Message.Key<LightApp> {
+    public companion object Key : ConstrainSingle.Key<LightApp> {
         public override val typeName: String get() = "LightApp"
     }
 
@@ -116,7 +116,7 @@ public class SimpleServiceMessage(
     public override val serviceId: Int,
     public override val content: String
 ) : ServiceMessage {
-    public companion object Key : Message.Key<ServiceMessage> {
+    public companion object Key : ConstrainSingle.Key<ServiceMessage> {
         public override val typeName: String get() = "ServiceMessage"
     }
 
@@ -146,7 +146,7 @@ public class SimpleServiceMessage(
  * @see SimpleServiceMessage
  */
 public interface ServiceMessage : RichMessage {
-    public companion object Key : Message.Key<ServiceMessage> {
+    public companion object Key : ConstrainSingle.Key<ServiceMessage> {
         public override val typeName: String get() = "ServiceMessage"
     }
 
@@ -258,7 +258,7 @@ internal class LongMessage internal constructor(override val content: String, va
     AbstractServiceMessage() {
     override val serviceId: Int get() = 35
 
-    companion object Key : Message.Key<LongMessage> {
+    companion object Key : ConstrainSingle.Key<LongMessage> {
         override val typeName: String get() = "LongMessage"
     }
 }

mirai-core-api/src/commonMain/kotlin/message/data/Voice.kt

@@ -21,7 +21,7 @@ import net.mamoe.mirai.utils.MiraiInternalApi
 @MiraiExperimentalApi
 public abstract class PttMessage : MessageContent {
 
-    public companion object Key : Message.Key<PttMessage> {
+    public companion object Key : ConstrainSingle.Key<PttMessage> {
         public override val typeName: String
             get() = "PttMessage"
     }
@@ -43,7 +43,7 @@ public class Voice @MiraiInternalApi constructor(
     private val _url: String
 ) : PttMessage() {
 
-    public companion object Key : Message.Key<Voice> {
+    public companion object Key : ConstrainSingle.Key<Voice> {
         override val typeName: String
             get() = "Voice"
     }

mirai-core-api/src/commonMain/kotlin/message/data/impl.kt

@@ -14,9 +14,6 @@
 package net.mamoe.mirai.message.data
 
 import net.mamoe.mirai.utils.MiraiExperimentalApi
-import kotlin.jvm.JvmMultifileClass
-import kotlin.jvm.JvmName
-import kotlin.jvm.JvmSynthetic
 import kotlin.native.concurrent.SharedImmutable
 
 // region image
@@ -25,7 +22,7 @@ import kotlin.native.concurrent.SharedImmutable
 //// IMPLEMENTATIONS ////
 /////////////////////////
 
-private fun Message.hasDuplicationOfConstrain(key: Message.Key<*>): Boolean {
+private fun Message.hasDuplicationOfConstrain(key: ConstrainSingle.Key<*>): Boolean {
     return when (this) {
         is SingleMessage -> (this as? ConstrainSingle<*>)?.key == key
         is CombinedMessage -> return this.left.hasDuplicationOfConstrain(key) || this.tail.hasDuplicationOfConstrain(key)
@@ -191,16 +188,9 @@ internal inline fun <T> List<T>.indexOfFirst(offset: Int, predicate: (T) -> Bool
 
 @JvmSynthetic
 @Suppress("UNCHECKED_CAST", "DEPRECATION_ERROR", "DEPRECATION")
-internal fun <M : Message> MessageChain.firstOrNullImpl(key: Message.Key<M>): M? = when (key) {
+internal fun <M : Message> MessageChain.firstOrNullImpl(key: ConstrainSingle.Key<M>): M? = when (key) {
-    At -> firstIsInstanceOrNull<At>()
-    AtAll -> firstIsInstanceOrNull<AtAll>()
-    PlainText -> firstIsInstanceOrNull<PlainText>()
-    Image -> firstIsInstanceOrNull<Image>()
     //  OnlineImage -> firstIsInstanceOrNull<OnlineImage>()
     //  OfflineImage -> firstIsInstanceOrNull<OfflineImage>()
-    GroupImage -> firstIsInstanceOrNull<GroupImage>()
-    FriendImage -> firstIsInstanceOrNull<FriendImage>()
-    Face -> firstIsInstanceOrNull<Face>()
     QuoteReply -> firstIsInstanceOrNull<QuoteReply>()
     MessageSource -> firstIsInstanceOrNull<MessageSource>()
     OnlineMessageSource -> firstIsInstanceOrNull<OnlineMessageSource>()
@@ -215,14 +205,9 @@ internal fun <M : Message> MessageChain.firstOrNullImpl(key: Message.Key<M>): M?
     LongMessage -> firstIsInstanceOrNull()
     RichMessage -> firstIsInstanceOrNull<RichMessage>()
     LightApp -> firstIsInstanceOrNull<LightApp>()
-    PokeMessage -> firstIsInstanceOrNull<PokeMessage>()
-    HummerMessage -> firstIsInstanceOrNull<HummerMessage>()
     FlashImage -> firstIsInstanceOrNull<FlashImage>()
     GroupFlashImage -> firstIsInstanceOrNull<GroupFlashImage>()
     FriendFlashImage -> firstIsInstanceOrNull<FriendFlashImage>()
-    CustomMessage -> firstIsInstanceOrNull()
-    CustomMessageMetadata -> firstIsInstanceOrNull()
-    ForwardMessage -> firstIsInstanceOrNull()
     PttMessage -> firstIsInstanceOrNull<PttMessage>()
     Voice -> firstIsInstanceOrNull<Voice>()
     else -> {

mirai-core-api/src/commonTest/kotlin/message.data/ConstrainSingleTest.kt

@@ -15,14 +15,15 @@ import kotlin.test.assertTrue
 
 
 internal class TestConstrainSingleMessage : ConstrainSingle<TestConstrainSingleMessage>, Any() {
-    companion object Key : Message.Key<TestConstrainSingleMessage> {
+    companion object Key : ConstrainSingle.Key<TestConstrainSingleMessage> {
         override val typeName: String
             get() = "TestMessage"
     }
 
     override fun toString(): String = "<TestConstrainSingleMessage#${super.hashCode()}>"
+    override fun contentToString(): String = ""
 
-    override val key: Message.Key<TestConstrainSingleMessage>
+    override val key: ConstrainSingle.Key<TestConstrainSingleMessage>
         get() = Key
 }
 

mirai-core/src/commonMain/kotlin/message/conversions.kt

@@ -436,14 +436,14 @@ internal fun List<ImMsgBody.Elem>.joinToMessageChain(groupIdOrZero: Long, botId:
                         CustomMessage.load(this)
                     }.fold(
                         onFailure = {
-                            if (it is CustomMessage.Key.CustomMessageFullDataDeserializeInternalException) {
+                            if (it is CustomMessage.Companion.CustomMessageFullDataDeserializeInternalException) {
                                 throw IllegalStateException(
                                     "Internal error: " +
                                             "exception while deserializing CustomMessage head data," +
                                             " data=${element.customElem.data.toUHexString()}", it
                                 )
                             } else {
-                                it as CustomMessage.Key.CustomMessageFullDataDeserializeUserException
+                                it as CustomMessage.Companion.CustomMessageFullDataDeserializeUserException
                                 throw IllegalStateException(
                                     "User error: " +
                                             "exception while deserializing CustomMessage body," +

mirai-core/src/commonMain/kotlin/message/imagesImpl.kt

@@ -146,7 +146,7 @@ internal val firstOnlineBotInstance: Bot get() = Bot.botInstancesSequence.firstO
 
 @Suppress("EXPOSED_SUPER_INTERFACE")
 internal interface OnlineImage : Image, ConstOriginUrlAware {
-    companion object Key : Message.Key<OnlineImage> {
+    companion object Key : ConstrainSingle.Key<OnlineImage> {
         override val typeName: String get() = "OnlineImage"
     }
 
@@ -160,7 +160,7 @@ internal interface OnlineImage : Image, ConstOriginUrlAware {
  * 一般由 [Contact.uploadImage] 得到
  */
 internal interface OfflineImage : Image {
-    companion object Key : Message.Key<OfflineImage> {
+    companion object Key : ConstrainSingle.Key<OfflineImage> {
         override val typeName: String get() = "OfflineImage"
     }
 }

mirai-core/src/jvmTest/kotlin/ContentEqualsTest.kt

@@ -11,21 +11,21 @@ package net.mamoe.mirai.internal
 
 import net.mamoe.mirai.message.data.ConstrainSingle
 import net.mamoe.mirai.message.data.Image
-import net.mamoe.mirai.message.data.Message
 import net.mamoe.mirai.message.data.buildMessageChain
 import kotlin.test.Test
 import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
 internal class TestConstrainSingleMessage : ConstrainSingle<TestConstrainSingleMessage>, Any() {
-    companion object Key : Message.Key<TestConstrainSingleMessage> {
+    companion object Key : ConstrainSingle.Key<TestConstrainSingleMessage> {
         override val typeName: String
             get() = "TestMessage"
     }
 
     override fun toString(): String = "<TestConstrainSingleMessage#${super.hashCode()}>"
+    override fun contentToString(): String = ""
 
-    override val key: Message.Key<TestConstrainSingleMessage>
+    override val key: ConstrainSingle.Key<TestConstrainSingleMessage>
         get() = Key
 }