src/vs/workbench/contrib/search/browser/anythingQuickAccess.ts/AnythingQuickAccessProvider/getEditorSymbolPicks
class AnythingQuickAccessProvider:	private getEditorSymbolPicks(query: IPreparedQuery, disposables: DisposableStore, token: CancellationToken): Promise<Picks<IAnythingQuickPickItem>> | null {
		const filterSegments = query.original.split(GotoSymbolQuickAccessProvider.PREFIX);
		const filter = filterSegments.length > 1 ? filterSegments[filterSegments.length - 1].trim() : undefined;
		if (typeof filter !== 'string') {
			return null; // we need to be searched for editor symbols via `@`
		}

		const activeGlobalPick = this.pickState.lastGlobalPicks?.active;
		if (!activeGlobalPick) {
			return null; // we need an active global pick to find symbols for
		}

		const activeGlobalResource = activeGlobalPick.resource;
		if (!activeGlobalResource || (!this.fileService.hasProvider(activeGlobalResource) && activeGlobalResource.scheme !== Schemas.untitled)) {
			return null; // we need a resource that we can resolve
		}

		if (activeGlobalPick.label.includes(GotoSymbolQuickAccessProvider.PREFIX) || activeGlobalPick.description?.includes(GotoSymbolQuickAccessProvider.PREFIX)) {
			if (filterSegments.length < 3) {
				return null; // require at least 2 `@` if our active pick contains `@` in label or description
			}
		}

		return this.doGetEditorSymbolPicks(activeGlobalPick, activeGlobalResource, filter, disposables, token);
	}