add proposal of CancellationError, https://github.com/microsoft/vscode/issues/93686

src/vs/base/common/errors.ts

@@ -142,6 +142,15 @@ export function isPromiseCanceledError(error: any): boolean {
 	return error instanceof Error && error.name === canceledName && error.message === canceledName;
 }
 
+// !!!IMPORTANT!!!
+// Do NOT change this class because it is also used as an API-type.
+export class CancellationError extends Error {
+	constructor() {
+		super(canceledName);
+		this.name = this.message;
+	}
+}
+
 /**
  * Returns an error that signals cancellation.
  */

src/vs/vscode.proposed.d.ts

@@ -18,6 +18,25 @@ import { Command } from 'vscode';
 
 declare module 'vscode' {
 
+	//#region https://github.com/microsoft/vscode/issues/93686
+
+	/**
+	 * An error type should be used to signal cancellation of an operation.
+	 *
+	 * This type can be used in response to a cancellation token or when an
+	 * operation is being cancelled by the executor of that operation.
+	 */
+	export class CancellationError extends Error {
+
+		/**
+		 * Creates a new cancellation error.
+		 */
+		constructor();
+	}
+
+
+	//#endregion
+
 	// #region auth provider: https://github.com/microsoft/vscode/issues/88309
 
 	/**

src/vs/workbench/api/common/extHost.api.impl.ts

@@ -1212,6 +1212,9 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 			ViewColumn: extHostTypes.ViewColumn,
 			WorkspaceEdit: extHostTypes.WorkspaceEdit,
 			// proposed api types
+			get CancellationError() {
+				return errors.CancellationError;
+			},
 			get RemoteAuthorityResolverError() {
 				// checkProposedApiEnabled(extension);
 				return extHostTypes.RemoteAuthorityResolverError;