import { Collection, MutationContext, PreferredContext } from '@collectable/core';
import { HashMap } from '@collectable/map';
export declare class HashSetStructure<T> implements Collection<T, T[]> {
    _map: HashMap.Instance<T, null>;
    /** @internal */
    constructor(mctx: MutationContext, _map: HashMap.Instance<T, null>);
    /** @internal */
    readonly '@@size': number;
    /** @internal */
    readonly '@@mctx': MutationContext;
    /** @internal */
    readonly '@@is-collection': true;
    /** @internal */
    '@@clone'(mctx: MutationContext): HashSetStructure<T>;
    /** @internal */
    '@@equals'(other: HashSetStructure<T>): boolean;
    /** @internal */
    '@@hash'(): number;
    /** @internal */
    '@@unwrap'(): T[];
    /** @internal */
    '@@unwrapInto'(target: T[]): T[];
    /** @internal */
    '@@createUnwrapTarget'(): T[];
    [Symbol.iterator](): IterableIterator<T>;
}
export declare function isHashSet<T>(arg: any): arg is HashSetStructure<T>;
export declare function cloneHashSet<T>(set: HashSetStructure<T>, mutability?: PreferredContext): HashSetStructure<T>;
export declare function createSet<T>(values?: T[] | Iterable<T>): HashSetStructure<T>;
export declare function extractMap<T>(set: HashSetStructure<T>): HashMap.Instance<T, null>;
export declare function emptySet<T>(mutability?: PreferredContext): HashSetStructure<T>;