diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index ef02a6a76..306b15f1a 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -13237,28 +13237,28 @@ interface Element extends Node, ARIAMixin, Animatable, ChildNode, NonDocumentTyp
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scroll)
      */
-    scroll(options?: ScrollToOptions): Promise<void>;
-    scroll(x: number, y: number): Promise<void>;
+    scroll(options?: ScrollToOptions): void;
+    scroll(x: number, y: number): void;
     /**
      * The **`scrollBy()`** method of the Element interface scrolls an element by the given amount.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollBy)
      */
-    scrollBy(options?: ScrollToOptions): Promise<void>;
-    scrollBy(x: number, y: number): Promise<void>;
+    scrollBy(options?: ScrollToOptions): void;
+    scrollBy(x: number, y: number): void;
     /**
      * The Element interface's **`scrollIntoView()`** method scrolls the element's ancestor containers such that the element on which scrollIntoView() is called is visible to the user.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollIntoView)
      */
-    scrollIntoView(arg?: boolean | ScrollIntoViewOptions): Promise<void>;
+    scrollIntoView(arg?: boolean | ScrollIntoViewOptions): void;
     /**
      * The **`scrollTo()`** method of the Element interface scrolls to a particular set of coordinates inside a given element.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollTo)
      */
-    scrollTo(options?: ScrollToOptions): Promise<void>;
-    scrollTo(x: number, y: number): Promise<void>;
+    scrollTo(options?: ScrollToOptions): void;
+    scrollTo(x: number, y: number): void;
     /**
      * The **`setAttribute()`** method of the Element interface sets the value of an attribute on the specified element. If the attribute already exists, the value is updated; otherwise a new attribute is added with the specified name and value.
      *
@@ -39325,22 +39325,22 @@ interface Window extends EventTarget, AnimationFrameProvider, GlobalEventHandler
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scroll)
      */
-    scroll(options?: ScrollToOptions): Promise<void>;
-    scroll(x: number, y: number): Promise<void>;
+    scroll(options?: ScrollToOptions): void;
+    scroll(x: number, y: number): void;
     /**
      * The **`Window.scrollBy()`** method scrolls the document in the window by the given amount.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollBy)
      */
-    scrollBy(options?: ScrollToOptions): Promise<void>;
-    scrollBy(x: number, y: number): Promise<void>;
+    scrollBy(options?: ScrollToOptions): void;
+    scrollBy(x: number, y: number): void;
     /**
      * **`Window.scrollTo()`** scrolls to a particular set of coordinates in the document.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollTo)
      */
-    scrollTo(options?: ScrollToOptions): Promise<void>;
-    scrollTo(x: number, y: number): Promise<void>;
+    scrollTo(options?: ScrollToOptions): void;
+    scrollTo(x: number, y: number): void;
     /**
      * The **`window.stop()`** stops further resource loading in the current browsing context, equivalent to the stop button in the browser.
      *
@@ -41489,22 +41489,22 @@ declare function resizeTo(width: number, height: number): void;
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scroll)
  */
-declare function scroll(options?: ScrollToOptions): Promise<void>;
-declare function scroll(x: number, y: number): Promise<void>;
+declare function scroll(options?: ScrollToOptions): void;
+declare function scroll(x: number, y: number): void;
 /**
  * The **`Window.scrollBy()`** method scrolls the document in the window by the given amount.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollBy)
  */
-declare function scrollBy(options?: ScrollToOptions): Promise<void>;
-declare function scrollBy(x: number, y: number): Promise<void>;
+declare function scrollBy(options?: ScrollToOptions): void;
+declare function scrollBy(x: number, y: number): void;
 /**
  * **`Window.scrollTo()`** scrolls to a particular set of coordinates in the document.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollTo)
  */
-declare function scrollTo(options?: ScrollToOptions): Promise<void>;
-declare function scrollTo(x: number, y: number): Promise<void>;
+declare function scrollTo(options?: ScrollToOptions): void;
+declare function scrollTo(x: number, y: number): void;
 /**
  * The **`window.stop()`** stops further resource loading in the current browsing context, equivalent to the stop button in the browser.
  *
diff --git a/baselines/ts5.5/dom.generated.d.ts b/baselines/ts5.5/dom.generated.d.ts
index 2c25f0954..8d3cc612d 100644
--- a/baselines/ts5.5/dom.generated.d.ts
+++ b/baselines/ts5.5/dom.generated.d.ts
@@ -13224,28 +13224,28 @@ interface Element extends Node, ARIAMixin, Animatable, ChildNode, NonDocumentTyp
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scroll)
      */
-    scroll(options?: ScrollToOptions): Promise<void>;
-    scroll(x: number, y: number): Promise<void>;
+    scroll(options?: ScrollToOptions): void;
+    scroll(x: number, y: number): void;
     /**
      * The **`scrollBy()`** method of the Element interface scrolls an element by the given amount.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollBy)
      */
-    scrollBy(options?: ScrollToOptions): Promise<void>;
-    scrollBy(x: number, y: number): Promise<void>;
+    scrollBy(options?: ScrollToOptions): void;
+    scrollBy(x: number, y: number): void;
     /**
      * The Element interface's **`scrollIntoView()`** method scrolls the element's ancestor containers such that the element on which scrollIntoView() is called is visible to the user.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollIntoView)
      */
-    scrollIntoView(arg?: boolean | ScrollIntoViewOptions): Promise<void>;
+    scrollIntoView(arg?: boolean | ScrollIntoViewOptions): void;
     /**
      * The **`scrollTo()`** method of the Element interface scrolls to a particular set of coordinates inside a given element.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollTo)
      */
-    scrollTo(options?: ScrollToOptions): Promise<void>;
-    scrollTo(x: number, y: number): Promise<void>;
+    scrollTo(options?: ScrollToOptions): void;
+    scrollTo(x: number, y: number): void;
     /**
      * The **`setAttribute()`** method of the Element interface sets the value of an attribute on the specified element. If the attribute already exists, the value is updated; otherwise a new attribute is added with the specified name and value.
      *
@@ -39299,22 +39299,22 @@ interface Window extends EventTarget, AnimationFrameProvider, GlobalEventHandler
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scroll)
      */
-    scroll(options?: ScrollToOptions): Promise<void>;
-    scroll(x: number, y: number): Promise<void>;
+    scroll(options?: ScrollToOptions): void;
+    scroll(x: number, y: number): void;
     /**
      * The **`Window.scrollBy()`** method scrolls the document in the window by the given amount.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollBy)
      */
-    scrollBy(options?: ScrollToOptions): Promise<void>;
-    scrollBy(x: number, y: number): Promise<void>;
+    scrollBy(options?: ScrollToOptions): void;
+    scrollBy(x: number, y: number): void;
     /**
      * **`Window.scrollTo()`** scrolls to a particular set of coordinates in the document.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollTo)
      */
-    scrollTo(options?: ScrollToOptions): Promise<void>;
-    scrollTo(x: number, y: number): Promise<void>;
+    scrollTo(options?: ScrollToOptions): void;
+    scrollTo(x: number, y: number): void;
     /**
      * The **`window.stop()`** stops further resource loading in the current browsing context, equivalent to the stop button in the browser.
      *
@@ -41463,22 +41463,22 @@ declare function resizeTo(width: number, height: number): void;
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scroll)
  */
-declare function scroll(options?: ScrollToOptions): Promise<void>;
-declare function scroll(x: number, y: number): Promise<void>;
+declare function scroll(options?: ScrollToOptions): void;
+declare function scroll(x: number, y: number): void;
 /**
  * The **`Window.scrollBy()`** method scrolls the document in the window by the given amount.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollBy)
  */
-declare function scrollBy(options?: ScrollToOptions): Promise<void>;
-declare function scrollBy(x: number, y: number): Promise<void>;
+declare function scrollBy(options?: ScrollToOptions): void;
+declare function scrollBy(x: number, y: number): void;
 /**
  * **`Window.scrollTo()`** scrolls to a particular set of coordinates in the document.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollTo)
  */
-declare function scrollTo(options?: ScrollToOptions): Promise<void>;
-declare function scrollTo(x: number, y: number): Promise<void>;
+declare function scrollTo(options?: ScrollToOptions): void;
+declare function scrollTo(x: number, y: number): void;
 /**
  * The **`window.stop()`** stops further resource loading in the current browsing context, equivalent to the stop button in the browser.
  *
diff --git a/baselines/ts5.6/dom.generated.d.ts b/baselines/ts5.6/dom.generated.d.ts
index 0103427c4..412c7b71a 100644
--- a/baselines/ts5.6/dom.generated.d.ts
+++ b/baselines/ts5.6/dom.generated.d.ts
@@ -13234,28 +13234,28 @@ interface Element extends Node, ARIAMixin, Animatable, ChildNode, NonDocumentTyp
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scroll)
      */
-    scroll(options?: ScrollToOptions): Promise<void>;
-    scroll(x: number, y: number): Promise<void>;
+    scroll(options?: ScrollToOptions): void;
+    scroll(x: number, y: number): void;
     /**
      * The **`scrollBy()`** method of the Element interface scrolls an element by the given amount.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollBy)
      */
-    scrollBy(options?: ScrollToOptions): Promise<void>;
-    scrollBy(x: number, y: number): Promise<void>;
+    scrollBy(options?: ScrollToOptions): void;
+    scrollBy(x: number, y: number): void;
     /**
      * The Element interface's **`scrollIntoView()`** method scrolls the element's ancestor containers such that the element on which scrollIntoView() is called is visible to the user.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollIntoView)
      */
-    scrollIntoView(arg?: boolean | ScrollIntoViewOptions): Promise<void>;
+    scrollIntoView(arg?: boolean | ScrollIntoViewOptions): void;
     /**
      * The **`scrollTo()`** method of the Element interface scrolls to a particular set of coordinates inside a given element.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollTo)
      */
-    scrollTo(options?: ScrollToOptions): Promise<void>;
-    scrollTo(x: number, y: number): Promise<void>;
+    scrollTo(options?: ScrollToOptions): void;
+    scrollTo(x: number, y: number): void;
     /**
      * The **`setAttribute()`** method of the Element interface sets the value of an attribute on the specified element. If the attribute already exists, the value is updated; otherwise a new attribute is added with the specified name and value.
      *
@@ -39322,22 +39322,22 @@ interface Window extends EventTarget, AnimationFrameProvider, GlobalEventHandler
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scroll)
      */
-    scroll(options?: ScrollToOptions): Promise<void>;
-    scroll(x: number, y: number): Promise<void>;
+    scroll(options?: ScrollToOptions): void;
+    scroll(x: number, y: number): void;
     /**
      * The **`Window.scrollBy()`** method scrolls the document in the window by the given amount.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollBy)
      */
-    scrollBy(options?: ScrollToOptions): Promise<void>;
-    scrollBy(x: number, y: number): Promise<void>;
+    scrollBy(options?: ScrollToOptions): void;
+    scrollBy(x: number, y: number): void;
     /**
      * **`Window.scrollTo()`** scrolls to a particular set of coordinates in the document.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollTo)
      */
-    scrollTo(options?: ScrollToOptions): Promise<void>;
-    scrollTo(x: number, y: number): Promise<void>;
+    scrollTo(options?: ScrollToOptions): void;
+    scrollTo(x: number, y: number): void;
     /**
      * The **`window.stop()`** stops further resource loading in the current browsing context, equivalent to the stop button in the browser.
      *
@@ -41486,22 +41486,22 @@ declare function resizeTo(width: number, height: number): void;
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scroll)
  */
-declare function scroll(options?: ScrollToOptions): Promise<void>;
-declare function scroll(x: number, y: number): Promise<void>;
+declare function scroll(options?: ScrollToOptions): void;
+declare function scroll(x: number, y: number): void;
 /**
  * The **`Window.scrollBy()`** method scrolls the document in the window by the given amount.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollBy)
  */
-declare function scrollBy(options?: ScrollToOptions): Promise<void>;
-declare function scrollBy(x: number, y: number): Promise<void>;
+declare function scrollBy(options?: ScrollToOptions): void;
+declare function scrollBy(x: number, y: number): void;
 /**
  * **`Window.scrollTo()`** scrolls to a particular set of coordinates in the document.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollTo)
  */
-declare function scrollTo(options?: ScrollToOptions): Promise<void>;
-declare function scrollTo(x: number, y: number): Promise<void>;
+declare function scrollTo(options?: ScrollToOptions): void;
+declare function scrollTo(x: number, y: number): void;
 /**
  * The **`window.stop()`** stops further resource loading in the current browsing context, equivalent to the stop button in the browser.
  *
diff --git a/baselines/ts5.9/dom.generated.d.ts b/baselines/ts5.9/dom.generated.d.ts
index 857e9bd69..a54dfb796 100644
--- a/baselines/ts5.9/dom.generated.d.ts
+++ b/baselines/ts5.9/dom.generated.d.ts
@@ -13234,28 +13234,28 @@ interface Element extends Node, ARIAMixin, Animatable, ChildNode, NonDocumentTyp
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scroll)
      */
-    scroll(options?: ScrollToOptions): Promise<void>;
-    scroll(x: number, y: number): Promise<void>;
+    scroll(options?: ScrollToOptions): void;
+    scroll(x: number, y: number): void;
     /**
      * The **`scrollBy()`** method of the Element interface scrolls an element by the given amount.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollBy)
      */
-    scrollBy(options?: ScrollToOptions): Promise<void>;
-    scrollBy(x: number, y: number): Promise<void>;
+    scrollBy(options?: ScrollToOptions): void;
+    scrollBy(x: number, y: number): void;
     /**
      * The Element interface's **`scrollIntoView()`** method scrolls the element's ancestor containers such that the element on which scrollIntoView() is called is visible to the user.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollIntoView)
      */
-    scrollIntoView(arg?: boolean | ScrollIntoViewOptions): Promise<void>;
+    scrollIntoView(arg?: boolean | ScrollIntoViewOptions): void;
     /**
      * The **`scrollTo()`** method of the Element interface scrolls to a particular set of coordinates inside a given element.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/scrollTo)
      */
-    scrollTo(options?: ScrollToOptions): Promise<void>;
-    scrollTo(x: number, y: number): Promise<void>;
+    scrollTo(options?: ScrollToOptions): void;
+    scrollTo(x: number, y: number): void;
     /**
      * The **`setAttribute()`** method of the Element interface sets the value of an attribute on the specified element. If the attribute already exists, the value is updated; otherwise a new attribute is added with the specified name and value.
      *
@@ -39322,22 +39322,22 @@ interface Window extends EventTarget, AnimationFrameProvider, GlobalEventHandler
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scroll)
      */
-    scroll(options?: ScrollToOptions): Promise<void>;
-    scroll(x: number, y: number): Promise<void>;
+    scroll(options?: ScrollToOptions): void;
+    scroll(x: number, y: number): void;
     /**
      * The **`Window.scrollBy()`** method scrolls the document in the window by the given amount.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollBy)
      */
-    scrollBy(options?: ScrollToOptions): Promise<void>;
-    scrollBy(x: number, y: number): Promise<void>;
+    scrollBy(options?: ScrollToOptions): void;
+    scrollBy(x: number, y: number): void;
     /**
      * **`Window.scrollTo()`** scrolls to a particular set of coordinates in the document.
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollTo)
      */
-    scrollTo(options?: ScrollToOptions): Promise<void>;
-    scrollTo(x: number, y: number): Promise<void>;
+    scrollTo(options?: ScrollToOptions): void;
+    scrollTo(x: number, y: number): void;
     /**
      * The **`window.stop()`** stops further resource loading in the current browsing context, equivalent to the stop button in the browser.
      *
@@ -41486,22 +41486,22 @@ declare function resizeTo(width: number, height: number): void;
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scroll)
  */
-declare function scroll(options?: ScrollToOptions): Promise<void>;
-declare function scroll(x: number, y: number): Promise<void>;
+declare function scroll(options?: ScrollToOptions): void;
+declare function scroll(x: number, y: number): void;
 /**
  * The **`Window.scrollBy()`** method scrolls the document in the window by the given amount.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollBy)
  */
-declare function scrollBy(options?: ScrollToOptions): Promise<void>;
-declare function scrollBy(x: number, y: number): Promise<void>;
+declare function scrollBy(options?: ScrollToOptions): void;
+declare function scrollBy(x: number, y: number): void;
 /**
  * **`Window.scrollTo()`** scrolls to a particular set of coordinates in the document.
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/scrollTo)
  */
-declare function scrollTo(options?: ScrollToOptions): Promise<void>;
-declare function scrollTo(x: number, y: number): Promise<void>;
+declare function scrollTo(options?: ScrollToOptions): void;
+declare function scrollTo(x: number, y: number): void;
 /**
  * The **`window.stop()`** stops further resource loading in the current browsing context, equivalent to the stop button in the browser.
  *
diff --git a/inputfiles/patches/cssom-view.kdl b/inputfiles/patches/cssom-view.kdl
index 58dc5121c..64c9b582c 100644
--- a/inputfiles/patches/cssom-view.kdl
+++ b/inputfiles/patches/cssom-view.kdl
@@ -14,3 +14,23 @@ interface-mixin DocumentOrShadowRoot {
     param y type=long
   }
 }
+
+// No implementation of Promise return values as of 2025-11
+interface Element {
+  method scroll returns=void signatureIndex=0
+  method scroll returns=void signatureIndex=1
+  method scrollBy returns=void signatureIndex=0
+  method scrollBy returns=void signatureIndex=1
+  method scrollTo returns=void signatureIndex=0
+  method scrollTo returns=void signatureIndex=1
+  method scrollIntoView returns=void signatureIndex=0
+}
+
+interface Window {
+  method scroll returns=void signatureIndex=0
+  method scroll returns=void signatureIndex=1
+  method scrollBy returns=void signatureIndex=0
+  method scrollBy returns=void signatureIndex=1
+  method scrollTo returns=void signatureIndex=0
+  method scrollTo returns=void signatureIndex=1
+}
diff --git a/src/build/patches.ts b/src/build/patches.ts
index 48b18c179..6ba1f1b3e 100644
--- a/src/build/patches.ts
+++ b/src/build/patches.ts
@@ -9,6 +9,7 @@ import type {
   Typed,
   Dictionary,
   Member,
+  Signature,
 } from "./types.js";
 import { readdir, readFile } from "fs/promises";
 import { merge } from "./helpers.js";
@@ -17,6 +18,10 @@ type DeepPartial<T> = T extends object
   ? { [K in keyof T]?: DeepPartial<T[K]> }
   : T;
 
+interface OverridableMethod extends Omit<Method, "signature"> {
+  signature: DeepPartial<Signature>[] | Record<number, DeepPartial<Signature>>;
+}
+
 function optionalMember<const T>(prop: string, type: T, value?: Value) {
   if (value === undefined) {
     return {};
@@ -154,7 +159,7 @@ function handleMixinandInterfaces(
 
   const event: Event[] = [];
   const property: Record<string, Partial<Property>> = {};
-  const method: Record<string, Partial<Method>> = {};
+  let method: Record<string, DeepPartial<OverridableMethod>> = {};
 
   for (const child of node.children) {
     switch (child.name) {
@@ -168,7 +173,10 @@ function handleMixinandInterfaces(
       }
       case "method": {
         const methodName = string(child.values[0]);
-        method[methodName] = handleMethod(child);
+        const m = handleMethod(child);
+        method = merge(method, {
+          [methodName]: m,
+        });
         break;
       }
       default:
@@ -238,7 +246,7 @@ function handleProperty(child: Node): Partial<Property> {
  * Handles a child node of type "method" and adds it to the method object.
  * @param child The child node to handle.
  */
-function handleMethod(child: Node): Partial<Method> {
+function handleMethod(child: Node): DeepPartial<OverridableMethod> {
   const name = string(child.values[0]);
 
   let typeNode: Node | undefined;
@@ -265,14 +273,24 @@ function handleMethod(child: Node): Partial<Method> {
     }
   }
 
-  const signature: Method["signature"] = [
-    {
-      param: params,
-      ...(typeNode
-        ? handleTyped(typeNode)
-        : { type: string(child.properties?.returns) }),
-    },
-  ];
+  // Determine the actual signature object
+  const signatureObj: DeepPartial<Signature> = {
+    param: params,
+    ...(typeNode
+      ? handleTyped(typeNode)
+      : {
+          type: string(child.properties?.returns),
+          subtype: undefined,
+        }),
+  };
+
+  let signature: OverridableMethod["signature"];
+  const signatureIndex = child.properties?.signatureIndex;
+  if (typeof signatureIndex == "number") {
+    signature = { [signatureIndex]: signatureObj };
+  } else {
+    signature = [signatureObj];
+  }
   return { name, signature };
 }