Introduce experimental common super interface `Identified` for Contact and Bot

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/Bot.kt

@@ -48,7 +48,7 @@ suspend inline fun <B : Bot> B.alsoLogin(): B = also { login() }
  */
 @Suppress("INAPPLICABLE_JVM_NAME")
 @OptIn(MiraiInternalAPI::class, LowLevelAPI::class)
-abstract class Bot : CoroutineScope, LowLevelBotAPIAccessor, BotJavaFriendlyAPI() {
+abstract class Bot : CoroutineScope, LowLevelBotAPIAccessor, BotJavaFriendlyAPI(), Identified {
     companion object {
         /**
          * 复制一份此时的 [Bot] 实例列表.
@@ -85,7 +85,7 @@ abstract class Bot : CoroutineScope, LowLevelBotAPIAccessor, BotJavaFriendlyAPI(
      * QQ 号码. 实际类型为 uint
      */
     @SinceMirai("0.32.0")
-    abstract val id: Long
+    abstract override val id: Long
 
     /**
      * 昵称

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt

@@ -7,7 +7,7 @@
  * https://github.com/mamoe/mirai/blob/master/LICENSE
  */
 
-@file:Suppress("EXPERIMENTAL_API_USAGE", "NOTHING_TO_INLINE")
+@file:Suppress("EXPERIMENTAL_API_USAGE", "NOTHING_TO_INLINE", "EXPERIMENTAL_OVERRIDE")
 
 package net.mamoe.mirai.contact
 
@@ -36,7 +36,7 @@ import kotlin.jvm.JvmSynthetic
  * @author Him188moe
  */ // 不要删除多平台结构 !!! kotlin bug
 @OptIn(MiraiInternalAPI::class, JavaFriendlyAPI::class)
-abstract class Contact : CoroutineScope, ContactJavaFriendlyAPI() {
+abstract class Contact : CoroutineScope, ContactJavaFriendlyAPI(), Identified {
     /**
      * 这个联系人所属 [Bot].
      */
@@ -52,7 +52,7 @@ abstract class Contact : CoroutineScope, ContactJavaFriendlyAPI() {
      * @see QQ.id
      * @see Group.id
      */
-    abstract val id: Long
+    abstract override val id: Long
 
     /**
      * 向这个对象发送消息.

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Identified.kt

+/*
+ * Copyright 2020 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.contact
+
+import net.mamoe.mirai.Bot
+import net.mamoe.mirai.utils.MiraiExperimentalAPI
+import net.mamoe.mirai.utils.SinceMirai
+
+/**
+ * 拥有 [id] 的对象.
+ * 此为 [Contact] 与 [Bot] 的唯一公共接口.
+ *
+ * @see Contact
+ * @see Bot
+ */
+@MiraiExperimentalAPI("classname may change")
+@SinceMirai("0.38.0")
+interface Identified {
+    /**
+     * QQ 号或群号.
+     */
+    val id: Long
+}
\ No newline at end of file