declare module '@glimmer/util/lib/destroyable-key' {
    /**
     * Classes Glimmer constructs itself declare this slot, so that
     * `@glimmer/destroyable` can hold their meta directly rather than in its
     * `WeakMap`. It lives here so packages below `@glimmer/destroyable` can declare
     * the slot without depending on it.
     *
     * Never write this onto an object Glimmer did not construct. Destroyables are
     * public through `@ember/destroyable` and can be any object a user hands in.
     */
    export const DESTROYABLE_META_KEY: unique symbol;
    export interface HasDestroyableMetaSlot {
        [DESTROYABLE_META_KEY]?: object | undefined;
    }
}