src/vs/workbench/services/history/browser/historyService.ts/HistoryService/reopenLastClosedEditor
class HistoryService:	async reopenLastClosedEditor(): Promise<void> {

		// Open editor if we have one
		const lastClosedEditor = this.recentlyClosedEditors.pop();
		let reopenClosedEditorPromise: Promise<void> | undefined = undefined;
		if (lastClosedEditor) {
			reopenClosedEditorPromise = this.doReopenLastClosedEditor(lastClosedEditor);
		}

		// Update context
		this.canReopenClosedEditorContextKey.set(this.recentlyClosedEditors.length > 0);

		return reopenClosedEditorPromise;
	}