Merge remote-tracking branch 'origin/command' into command

# Conflicts:
#	backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/internal/command/executeCommandInternal.kt

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/command/CommandExecuteResult.kt

@@ -62,7 +62,7 @@ public sealed class CommandExecuteResult {
     /** 执行执行时发生了一个非法参数错误 */
     public class IllegalArgument(
         /** 指令执行时发生的错误 */
-        public override val exception: IllegalArgumentException,
+        public override val exception: IllegalCommandArgumentException,
         /** 尝试执行的指令 */
         public override val command: Command,
         /** 尝试执行的指令名 */
@@ -184,7 +184,7 @@ public fun CommandExecuteResult.isExecutionException(): Boolean {
 }
 
 /**
- * 当 [this] 为 [CommandExecuteResult.ExecutionFailed] 时返回 `true`
+ * 当 [this] 为 [CommandExecuteResult.PermissionDenied] 时返回 `true`
  */
 @JvmSynthetic
 public fun CommandExecuteResult.isPermissionDenied(): Boolean {
@@ -196,7 +196,7 @@ public fun CommandExecuteResult.isPermissionDenied(): Boolean {
 }
 
 /**
- * 当 [this] 为 [CommandExecuteResult.ExecutionFailed] 时返回 `true`
+ * 当 [this] 为 [CommandExecuteResult.CommandNotFound] 时返回 `true`
  */
 @JvmSynthetic
 public fun CommandExecuteResult.isCommandNotFound(): Boolean {
@@ -208,7 +208,7 @@ public fun CommandExecuteResult.isCommandNotFound(): Boolean {
 }
 
 /**
- * 当 [this] 为 [CommandExecuteResult.ExecutionFailed] 或 [CommandExecuteResult.CommandNotFound] 时返回 `true`
+ * 当 [this] 为 [CommandExecuteResult.ExecutionFailed], [CommandExecuteResult.IllegalArgument] 或 [CommandExecuteResult.CommandNotFound] 时返回 `true`
  */
 @JvmSynthetic
 public fun CommandExecuteResult.isFailure(): Boolean {

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/command/CommandSender.kt

@@ -281,6 +281,13 @@ public sealed class AbstractCommandSender : CommandSender, CoroutineScope {
         if (this is CommandSenderOnMessage<*>) {
             val cause = e.rootCauseOrSelf
 
+            // TODO: 2020/10/17
+            //      CommandArgumentParserException 作为 IllegalCommandArgumentException 不会再进入此函数
+            //      已在
+            //       - [console]  CommandManagerImpl.commandListener
+            //       - [terminal] ConsoleThread.kt
+            //      处理
+
             val message = cause
                 .takeIf { it is CommandArgumentParserException }?.message
                 ?: "${cause::class.simpleName.orEmpty()}: ${cause.message}"

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/command/IllegalCommandArgumentException.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2019-2020 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 AFFERO GENERAL PUBLIC LICENSE version 3 license that can be found via the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ *
+ */
+
+@file:Suppress("unused")
+
+package net.mamoe.mirai.console.command
+
+import net.mamoe.mirai.console.command.descriptor.CommandArgumentParserException
+
+/**
+ * 在处理参数时遇到的 _正常_ 错误. 如参数不符合规范, 参数值越界等.
+ *
+ * [message] 将会发送给指令调用方.
+ *
+ * @see CommandArgumentParserException
+ */
+public open class IllegalCommandArgumentException : IllegalArgumentException {
+    public constructor() : super()
+    public constructor(message: String?) : super(message)
+    public constructor(message: String?, cause: Throwable?) : super(message, cause)
+    public constructor(cause: Throwable?) : super(cause)
+}

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/command/descriptor/CommandArgumentParserException.kt

@@ -11,15 +11,18 @@
 
 package net.mamoe.mirai.console.command.descriptor
 
+import net.mamoe.mirai.console.command.IllegalCommandArgumentException
+
 /**
  * 在解析参数时遇到的 _正常_ 错误. 如参数不符合规范等.
  *
  * [message] 将会发送给指令调用方.
  *
+ * @see IllegalCommandArgumentException
  * @see CommandValueArgumentParser
  * @see CommandValueArgumentParser.illegalArgument
  */
-public class CommandArgumentParserException : RuntimeException {
+public class CommandArgumentParserException : IllegalCommandArgumentException {
     public constructor() : super()
     public constructor(message: String?) : super(message)
     public constructor(message: String?, cause: Throwable?) : super(message, cause)

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/command/descriptor/TypeVariant.kt

@@ -9,11 +9,18 @@
 
 package net.mamoe.mirai.console.command.descriptor
 
+import net.mamoe.mirai.console.command.parse.CommandCall
+import net.mamoe.mirai.console.command.parse.CommandCallParser
 import net.mamoe.mirai.console.command.parse.RawCommandArgument
 import net.mamoe.mirai.message.data.MessageContent
 import kotlin.reflect.KType
 import kotlin.reflect.typeOf
 
+/**
+ * Implicit type variant specified by [CommandCallParser].
+ *
+ * [TypeVariant] is not necessary for all [CommandCall]s.
+ */
 @ExperimentalCommandDescriptors
 public interface TypeVariant<out OutType> {
     /**