Override MessageEventTarget's events' this-parameter type (#1882)

* Override MessageEventTarget's events' this type

* do not override this on globals

* Default to this: this and add overrides to exclude

There are only 3 right now.

* Switch to this:T for MessagePort and immediate subtypes

This allows more variable in non-immediate subtypes

baselines/audioworklet.generated.d.ts

@@ -682,14 +682,14 @@ interface MessageEventTargetEventMap {
     "messageerror": MessageEvent;
 }
 
-interface MessageEventTarget {
+interface MessageEventTarget<T> {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/message_event) */
-    onmessage: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
+    onmessage: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/messageerror_event) */
-    onmessageerror: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
-    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    onmessageerror: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
+    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
-    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
@@ -703,7 +703,7 @@ interface MessagePortEventMap extends MessageEventTargetEventMap {
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MessagePort)
  */
-interface MessagePort extends EventTarget, MessageEventTarget {
+interface MessagePort extends EventTarget, MessageEventTarget<MessagePort> {
     /**
      * Disconnects the port, so that it is no longer active.
      *

baselines/dom.generated.d.ts

@@ -16389,14 +16389,14 @@ interface MessageEventTargetEventMap {
     "messageerror": MessageEvent;
 }
 
-interface MessageEventTarget {
+interface MessageEventTarget<T> {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/message_event) */
-    onmessage: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
+    onmessage: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/messageerror_event) */
-    onmessageerror: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
-    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    onmessageerror: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
+    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
-    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
@@ -16410,7 +16410,7 @@ interface MessagePortEventMap extends MessageEventTargetEventMap {
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MessagePort)
  */
-interface MessagePort extends EventTarget, MessageEventTarget {
+interface MessagePort extends EventTarget, MessageEventTarget<MessagePort> {
     /**
      * Disconnects the port, so that it is no longer active.
      *
@@ -27259,16 +27259,14 @@ interface WindowSessionStorage {
 }
 
 interface WorkerEventMap extends AbstractWorkerEventMap, MessageEventTargetEventMap {
-    "message": MessageEvent;
-    "messageerror": MessageEvent;
 }
 
 /**
  * This Web Workers API interface represents a background task that can be easily created and can send messages back to its creator. Creating a worker is as simple as calling the Worker() constructor and specifying a script to be run in the worker thread.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Worker)
  */
-interface Worker extends EventTarget, AbstractWorker, MessageEventTarget {
+interface Worker extends EventTarget, AbstractWorker, MessageEventTarget<Worker> {
     /**
      * Clones message and transmits it to worker's global environment. transfer can be passed as a list of objects that are to be transferred rather than cloned.
      *

baselines/serviceworker.generated.d.ts

@@ -3759,14 +3759,14 @@ interface MessageEventTargetEventMap {
     "messageerror": MessageEvent;
 }
 
-interface MessageEventTarget {
+interface MessageEventTarget<T> {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/message_event) */
-    onmessage: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
+    onmessage: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/messageerror_event) */
-    onmessageerror: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
-    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    onmessageerror: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
+    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
-    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
@@ -3780,7 +3780,7 @@ interface MessagePortEventMap extends MessageEventTargetEventMap {
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MessagePort)
  */
-interface MessagePort extends EventTarget, MessageEventTarget {
+interface MessagePort extends EventTarget, MessageEventTarget<MessagePort> {
     /**
      * Disconnects the port, so that it is no longer active.
      *

baselines/sharedworker.generated.d.ts

@@ -3648,14 +3648,14 @@ interface MessageEventTargetEventMap {
     "messageerror": MessageEvent;
 }
 
-interface MessageEventTarget {
+interface MessageEventTarget<T> {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/message_event) */
-    onmessage: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
+    onmessage: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/messageerror_event) */
-    onmessageerror: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
-    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    onmessageerror: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
+    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
-    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
@@ -3669,7 +3669,7 @@ interface MessagePortEventMap extends MessageEventTargetEventMap {
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MessagePort)
  */
-interface MessagePort extends EventTarget, MessageEventTarget {
+interface MessagePort extends EventTarget, MessageEventTarget<MessagePort> {
     /**
      * Disconnects the port, so that it is no longer active.
      *
@@ -7841,16 +7841,14 @@ interface WindowOrWorkerGlobalScope {
 }
 
 interface WorkerEventMap extends AbstractWorkerEventMap, MessageEventTargetEventMap {
-    "message": MessageEvent;
-    "messageerror": MessageEvent;
 }
 
 /**
  * This Web Workers API interface represents a background task that can be easily created and can send messages back to its creator. Creating a worker is as simple as calling the Worker() constructor and specifying a script to be run in the worker thread.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Worker)
  */
-interface Worker extends EventTarget, AbstractWorker, MessageEventTarget {
+interface Worker extends EventTarget, AbstractWorker, MessageEventTarget<Worker> {
     /**
      * Clones message and transmits it to worker's global environment. transfer can be passed as a list of objects that are to be transferred rather than cloned.
      *

baselines/ts5.5/audioworklet.generated.d.ts

@@ -682,14 +682,14 @@ interface MessageEventTargetEventMap {
     "messageerror": MessageEvent;
 }
 
-interface MessageEventTarget {
+interface MessageEventTarget<T> {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/message_event) */
-    onmessage: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
+    onmessage: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/messageerror_event) */
-    onmessageerror: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
-    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    onmessageerror: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
+    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
-    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
@@ -703,7 +703,7 @@ interface MessagePortEventMap extends MessageEventTargetEventMap {
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MessagePort)
  */
-interface MessagePort extends EventTarget, MessageEventTarget {
+interface MessagePort extends EventTarget, MessageEventTarget<MessagePort> {
     /**
      * Disconnects the port, so that it is no longer active.
      *

baselines/ts5.5/dom.generated.d.ts

@@ -16369,14 +16369,14 @@ interface MessageEventTargetEventMap {
     "messageerror": MessageEvent;
 }
 
-interface MessageEventTarget {
+interface MessageEventTarget<T> {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/message_event) */
-    onmessage: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
+    onmessage: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/messageerror_event) */
-    onmessageerror: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
-    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    onmessageerror: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
+    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
-    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
@@ -16390,7 +16390,7 @@ interface MessagePortEventMap extends MessageEventTargetEventMap {
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MessagePort)
  */
-interface MessagePort extends EventTarget, MessageEventTarget {
+interface MessagePort extends EventTarget, MessageEventTarget<MessagePort> {
     /**
      * Disconnects the port, so that it is no longer active.
      *
@@ -27237,16 +27237,14 @@ interface WindowSessionStorage {
 }
 
 interface WorkerEventMap extends AbstractWorkerEventMap, MessageEventTargetEventMap {
-    "message": MessageEvent;
-    "messageerror": MessageEvent;
 }
 
 /**
  * This Web Workers API interface represents a background task that can be easily created and can send messages back to its creator. Creating a worker is as simple as calling the Worker() constructor and specifying a script to be run in the worker thread.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Worker)
  */
-interface Worker extends EventTarget, AbstractWorker, MessageEventTarget {
+interface Worker extends EventTarget, AbstractWorker, MessageEventTarget<Worker> {
     /**
      * Clones message and transmits it to worker's global environment. transfer can be passed as a list of objects that are to be transferred rather than cloned.
      *

baselines/ts5.5/serviceworker.generated.d.ts

@@ -3759,14 +3759,14 @@ interface MessageEventTargetEventMap {
     "messageerror": MessageEvent;
 }
 
-interface MessageEventTarget {
+interface MessageEventTarget<T> {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/message_event) */
-    onmessage: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
+    onmessage: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/DedicatedWorkerGlobalScope/messageerror_event) */
-    onmessageerror: ((this: MessageEventTarget, ev: MessageEvent) => any) | null;
-    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    onmessageerror: ((this: MessageEventTarget<T>, ev: MessageEvent) => any) | null;
+    addEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
-    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener<K extends keyof MessageEventTargetEventMap>(type: K, listener: (this: MessageEventTarget<T>, ev: MessageEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
@@ -3780,7 +3780,7 @@ interface MessagePortEventMap extends MessageEventTargetEventMap {
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MessagePort)
  */
-interface MessagePort extends EventTarget, MessageEventTarget {
+interface MessagePort extends EventTarget, MessageEventTarget<MessagePort> {
     /**
      * Disconnects the port, so that it is no longer active.
      *