tests/cases/compiler/immutable.ts(341,22): error TS2430: Interface 'Keyed<K, V>' incorrectly extends interface 'Collection<K, V>'.
  Types of property 'toSeq' are incompatible.
    Type '() => Keyed<K, V>' is not assignable to type '() => this'.
      Type 'Keyed<K, V>' is not assignable to type 'this'.
tests/cases/compiler/immutable.ts(359,22): error TS2430: Interface 'Indexed<T>' incorrectly extends interface 'Collection<number, T>'.
  Types of property 'toSeq' are incompatible.
    Type '() => Indexed<T>' is not assignable to type '() => this'.
      Type 'Indexed<T>' is not assignable to type 'this'.
tests/cases/compiler/immutable.ts(391,22): error TS2430: Interface 'Set<T>' incorrectly extends interface 'Collection<never, T>'.
  Types of property 'toSeq' are incompatible.
    Type '() => Set<T>' is not assignable to type '() => this'.
      Type 'Set<T>' is not assignable to type 'this'.


==== tests/cases/compiler/complex.ts (0 errors) ====
    interface Ara<T> { t: T }
    interface Collection<K, V> {
        map<M>(mapper: (value: V, key: K, iter: this) => M): Collection<K, M>;
        flatMap<M>(mapper: (value: V, key: K, iter: this) => Ara<M>, context?: any): Collection<K, M>;
        // these seem necessary to push it over the top for memory usage
        reduce<R>(reducer: (reduction: R, value: V, key: K, iter: this) => R, initialReduction: R, context?: any): R;
        reduce<R>(reducer: (reduction: V | R, value: V, key: K, iter: this) => R): R;
        toSeq(): Seq<K, V>;
    }
    interface Seq<K, V> extends Collection<K, V> {
    }
    interface N1<T> extends Collection<void, T> {
        map<M>(mapper: (value: T, key: void, iter: this) => M): N1<M>;
        flatMap<M>(mapper: (value: T, key: void, iter: this) => Ara<M>, context?: any): N1<M>;
    }
    interface N2<T> extends N1<T> {
        map<M>(mapper: (value: T, key: void, iter: this) => M): N2<M>;
        flatMap<M>(mapper: (value: T, key: void, iter: this) => Ara<M>, context?: any): N2<M>;
        toSeq(): N2<T>;
    }
==== tests/cases/compiler/immutable.ts (3 errors) ====
    // Test that complex recursive collections can pass the `extends` assignability check without
    // running out of memory. This bug was exposed in Typescript 2.4 when more generic signatures
    // started being checked.
    declare module Immutable {
      export function fromJS(jsValue: any, reviver?: (key: string | number, sequence: Collection.Keyed<string, any> | Collection.Indexed<any>, path?: Array<string | number>) => any): any;
      export function is(first: any, second: any): boolean;
      export function hash(value: any): number;
      export function isImmutable(maybeImmutable: any): maybeImmutable is Collection<any, any>;
      export function isCollection(maybeCollection: any): maybeCollection is Collection<any, any>;
      export function isKeyed(maybeKeyed: any): maybeKeyed is Collection.Keyed<any, any>;
      export function isIndexed(maybeIndexed: any): maybeIndexed is Collection.Indexed<any>;
      export function isAssociative(maybeAssociative: any): maybeAssociative is Collection.Keyed<any, any> | Collection.Indexed<any>;
      export function isOrdered(maybeOrdered: any): boolean;
      export function isValueObject(maybeValue: any): maybeValue is ValueObject;
      export interface ValueObject {
        equals(other: any): boolean;
        hashCode(): number;
      }
      export module List {
        function isList(maybeList: any): maybeList is List<any>;
        function of<T>(...values: Array<T>): List<T>;
      }
      export function List(): List<any>;
      export function List<T>(): List<T>;
      export function List<T>(collection: Iterable<T>): List<T>;
      export interface List<T> extends Collection.Indexed<T> {
        // Persistent changes
        set(index: number, value: T): List<T>;
        delete(index: number): List<T>;
        remove(index: number): List<T>;
        insert(index: number, value: T): List<T>;
        clear(): List<T>;
        push(...values: Array<T>): List<T>;
        pop(): List<T>;
        unshift(...values: Array<T>): List<T>;
        shift(): List<T>;
        update(index: number, notSetValue: T, updater: (value: T) => T): this;
        update(index: number, updater: (value: T) => T): this;
        update<R>(updater: (value: this) => R): R;
        merge(...collections: Array<Collection.Indexed<T> | Array<T>>): this;
        mergeWith(merger: (oldVal: T, newVal: T, key: number) => T, ...collections: Array<Collection.Indexed<T> | Array<T>>): this;
        mergeDeep(...collections: Array<Collection.Indexed<T> | Array<T>>): this;
        mergeDeepWith(merger: (oldVal: T, newVal: T, key: number) => T, ...collections: Array<Collection.Indexed<T> | Array<T>>): this;
        setSize(size: number): List<T>;
        // Deep persistent changes
        setIn(keyPath: Iterable<any>, value: any): this;
        deleteIn(keyPath: Iterable<any>): this;
        removeIn(keyPath: Iterable<any>): this;
        updateIn(keyPath: Iterable<any>, notSetValue: any, updater: (value: any) => any): this;
        updateIn(keyPath: Iterable<any>, updater: (value: any) => any): this;
        mergeIn(keyPath: Iterable<any>, ...collections: Array<any>): this;
        mergeDeepIn(keyPath: Iterable<any>, ...collections: Array<any>): this;
        // Transient changes
        withMutations(mutator: (mutable: this) => any): this;
        asMutable(): this;
        asImmutable(): this;
        // Sequence algorithms
        concat<C>(...valuesOrCollections: Array<Iterable<C> | C>): List<T | C>;
        map<M>(mapper: (value: T, key: number, iter: this) => M, context?: any): List<M>;
        flatMap<M>(mapper: (value: T, key: number, iter: this) => Iterable<M>, context?: any): List<M>;
        filter<F extends T>(predicate: (value: T, index: number, iter: this) => value is F, context?: any): List<F>;
        filter(predicate: (value: T, index: number, iter: this) => any, context?: any): this;
      }
      export module Map {
        function isMap(maybeMap: any): maybeMap is Map<any, any>;
        function of(...keyValues: Array<any>): Map<any, any>;
      }
      export function Map<K, V>(collection: Iterable<[K, V]>): Map<K, V>;
      export function Map<T>(collection: Iterable<Iterable<T>>): Map<T, T>;
      export function Map<V>(obj: {[key: string]: V}): Map<string, V>;
      export function Map<K, V>(): Map<K, V>;
      export function Map(): Map<any, any>;
      export interface Map<K, V> extends Collection.Keyed<K, V> {
        // Persistent changes
        set(key: K, value: V): this;
        delete(key: K): this;
        remove(key: K): this;
        deleteAll(keys: Iterable<K>): this;
        removeAll(keys: Iterable<K>): this;
        clear(): this;
        update(key: K, notSetValue: V, updater: (value: V) => V): this;
        update(key: K, updater: (value: V) => V): this;
        update<R>(updater: (value: this) => R): R;
        merge(...collections: Array<Collection<K, V> | {[key: string]: V}>): this;
        mergeWith(merger: (oldVal: V, newVal: V, key: K) => V, ...collections: Array<Collection<K, V> | {[key: string]: V}>): this;
        mergeDeep(...collections: Array<Collection<K, V> | {[key: string]: V}>): this;
        mergeDeepWith(merger: (oldVal: V, newVal: V, key: K) => V, ...collections: Array<Collection<K, V> | {[key: string]: V}>): this;
        // Deep persistent changes
        setIn(keyPath: Iterable<any>, value: any): this;
        deleteIn(keyPath: Iterable<any>): this;
        removeIn(keyPath: Iterable<any>): this;
        updateIn(keyPath: Iterable<any>, notSetValue: any, updater: (value: any) => any): this;
        updateIn(keyPath: Iterable<any>, updater: (value: any) => any): this;
        mergeIn(keyPath: Iterable<any>, ...collections: Array<any>): this;
        mergeDeepIn(keyPath: Iterable<any>, ...collections: Array<any>): this;
        // Transient changes
        withMutations(mutator: (mutable: this) => any): this;
        asMutable(): this;
        asImmutable(): this;
        // Sequence algorithms
        concat<KC, VC>(...collections: Array<Iterable<[KC, VC]>>): Map<K | KC, V | VC>;
        concat<C>(...collections: Array<{[key: string]: C}>): Map<K | string, V | C>;
        map<M>(mapper: (value: V, key: K, iter: this) => M, context?: any): Map<K, M>;
        mapKeys<M>(mapper: (key: K, value: V, iter: this) => M, context?: any): Map<M, V>;
        mapEntries<KM, VM>(mapper: (entry: [K, V], index: number, iter: this) => [KM, VM], context?: any): Map<KM, VM>;
        flatMap<M>(mapper: (value: V, key: K, iter: this) => Iterable<M>, context?: any): Map<any, any>;
        filter<F extends V>(predicate: (value: V, key: K, iter: this) => value is F, context?: any): Map<K, F>;
        filter(predicate: (value: V, key: K, iter: this) => any, context?: any): this;
      }
      export module OrderedMap {
        function isOrderedMap(maybeOrderedMap: any): maybeOrderedMap is OrderedMap<any, any>;
      }
      export function OrderedMap<K, V>(collection: Iterable<[K, V]>): OrderedMap<K, V>;
      export function OrderedMap<T>(collection: Iterable<Iterable<T>>): OrderedMap<T, T>;
      export function OrderedMap<V>(obj: {[key: string]: V}): OrderedMap<string, V>;
      export function OrderedMap<K, V>(): OrderedMap<K, V>;
      export function OrderedMap(): OrderedMap<any, any>;
      export interface OrderedMap<K, V> extends Map<K, V> {
        // Sequence algorithms
        concat<KC, VC>(...collections: Array<Iterable<[KC, VC]>>): OrderedMap<K | KC, V | VC>;
        concat<C>(...collections: Array<{[key: string]: C}>): OrderedMap<K | string, V | C>;
        map<M>(mapper: (value: V, key: K, iter: this) => M, context?: any): OrderedMap<K, M>;
        mapKeys<M>(mapper: (key: K, value: V, iter: this) => M, context?: any): OrderedMap<M, V>;
        mapEntries<KM, VM>(mapper: (entry: [K, V], index: number, iter: this) => [KM, VM], context?: any): OrderedMap<KM, VM>;
        flatMap<M>(mapper: (value: V, key: K, iter: this) => Iterable<M>, context?: any): OrderedMap<any, any>;
        filter<F extends V>(predicate: (value: V, key: K, iter: this) => value is F, context?: any): OrderedMap<K, F>;
        filter(predicate: (value: V, key: K, iter: this) => any, context?: any): this;
      }
      export module Set {
        function isSet(maybeSet: any): maybeSet is Set<any>;
        function of<T>(...values: Array<T>): Set<T>;
        function fromKeys<T>(iter: Collection<T, any>): Set<T>;
        function fromKeys(obj: {[key: string]: any}): Set<string>;
        function intersect<T>(sets: Iterable<Iterable<T>>): Set<T>;
        function union<T>(sets: Iterable<Iterable<T>>): Set<T>;
      }
      export function Set(): Set<any>;
      export function Set<T>(): Set<T>;
      export function Set<T>(collection: Iterable<T>): Set<T>;
      export interface Set<T> extends Collection.Set<T> {
        // Persistent changes
        add(value: T): this;
        delete(value: T): this;
        remove(value: T): this;
        clear(): this;
        union(...collections: Array<Collection<any, T> | Array<T>>): this;
        merge(...collections: Array<Collection<any, T> | Array<T>>): this;
        intersect(...collections: Array<Collection<any, T> | Array<T>>): this;
        subtract(...collections: Array<Collection<any, T> | Array<T>>): this;
        // Transient changes
        withMutations(mutator: (mutable: this) => any): this;
        asMutable(): this;
        asImmutable(): this;
        // Sequence algorithms
        concat<C>(...valuesOrCollections: Array<Iterable<C> | C>): Set<T | C>;
        map<M>(mapper: (value: T, key: never, iter: this) => M, context?: any): Set<M>;
        flatMap<M>(mapper: (value: T, key: never, iter: this) => Iterable<M>, context?: any): Set<M>;
        filter<F extends T>(predicate: (value: T, key: never, iter: this) => value is F, context?: any): Set<F>;
        filter(predicate: (value: T, key: never, iter: this) => any, context?: any): this;
      }
      export module OrderedSet {
        function isOrderedSet(maybeOrderedSet: any): boolean;
        function of<T>(...values: Array<T>): OrderedSet<T>;
        function fromKeys<T>(iter: Collection<T, any>): OrderedSet<T>;
        function fromKeys(obj: {[key: string]: any}): OrderedSet<string>;
      }
      export function OrderedSet(): OrderedSet<any>;
      export function OrderedSet<T>(): OrderedSet<T>;
      export function OrderedSet<T>(collection: Iterable<T>): OrderedSet<T>;
      export interface OrderedSet<T> extends Set<T> {
        // Sequence algorithms
        concat<C>(...valuesOrCollections: Array<Iterable<C> | C>): OrderedSet<T | C>;
        map<M>(mapper: (value: T, key: never, iter: this) => M, context?: any): OrderedSet<M>;
        flatMap<M>(mapper: (value: T, key: never, iter: this) => Iterable<M>, context?: any): OrderedSet<M>;
        filter<F extends T>(predicate: (value: T, key: never, iter: this) => value is F, context?: any): OrderedSet<F>;
        filter(predicate: (value: T, key: never, iter: this) => any, context?: any): this;
        zip(...collections: Array<Collection<any, any>>): OrderedSet<any>;
        zipWith<U, Z>(zipper: (value: T, otherValue: U) => Z, otherCollection: Collection<any, U>): OrderedSet<Z>;
        zipWith<U, V, Z>(zipper: (value: T, otherValue: U, thirdValue: V) => Z, otherCollection: Collection<any, U>, thirdCollection: Collection<any, V>): OrderedSet<Z>;
        zipWith<Z>(zipper: (...any: Array<any>) => Z, ...collections: Array<Collection<any, any>>): OrderedSet<Z>;
      }
      export module Stack {
        function isStack(maybeStack: any): maybeStack is Stack<any>;
        function of<T>(...values: Array<T>): Stack<T>;
      }
      export function Stack(): Stack<any>;
      export function Stack<T>(): Stack<T>;
      export function Stack<T>(collection: Iterable<T>): Stack<T>;
      export interface Stack<T> extends Collection.Indexed<T> {
        // Reading values
        peek(): T | undefined;
        // Persistent changes
        clear(): Stack<T>;
        unshift(...values: Array<T>): Stack<T>;
        unshiftAll(iter: Iterable<T>): Stack<T>;
        shift(): Stack<T>;
        push(...values: Array<T>): Stack<T>;
        pushAll(iter: Iterable<T>): Stack<T>;
        pop(): Stack<T>;
        // Transient changes
        withMutations(mutator: (mutable: this) => any): this;
        asMutable(): this;
        asImmutable(): this;
        // Sequence algorithms
        concat<C>(...valuesOrCollections: Array<Iterable<C> | C>): Stack<T | C>;
        map<M>(mapper: (value: T, key: number, iter: this) => M, context?: any): Stack<M>;
        flatMap<M>(mapper: (value: T, key: number, iter: this) => Iterable<M>, context?: any): Stack<M>;
        filter<F extends T>(predicate: (value: T, index: number, iter: this) => value is F, context?: any): Set<F>;
        filter(predicate: (value: T, index: number, iter: this) => any, context?: any): this;
      }
      export function Range(start?: number, end?: number, step?: number): Seq.Indexed<number>;
      export function Repeat<T>(value: T, times?: number): Seq.Indexed<T>;
      export module Record {
        export function isRecord(maybeRecord: any): maybeRecord is Record.Instance<any>;
        export function getDescriptiveName(record: Instance<any>): string;
        export interface Class<T extends Object> {
          (values?: Partial<T> | Iterable<[string, any]>): Instance<T> & Readonly<T>;
          new (values?: Partial<T> | Iterable<[string, any]>): Instance<T> & Readonly<T>;
        }
        export interface Instance<T extends Object> {
          readonly size: number;
          // Reading values
          has(key: string): boolean;
          get<K extends keyof T>(key: K): T[K];
          // Reading deep values
          hasIn(keyPath: Iterable<any>): boolean;
          getIn(keyPath: Iterable<any>): any;
          // Value equality
          equals(other: any): boolean;
          hashCode(): number;
          // Persistent changes
          set<K extends keyof T>(key: K, value: T[K]): this;
          update<K extends keyof T>(key: K, updater: (value: T[K]) => T[K]): this;
          merge(...collections: Array<Partial<T> | Iterable<[string, any]>>): this;
          mergeDeep(...collections: Array<Partial<T> | Iterable<[string, any]>>): this;
          mergeWith(merger: (oldVal: any, newVal: any, key: keyof T) => any, ...collections: Array<Partial<T> | Iterable<[string, any]>>): this;
          mergeDeepWith(merger: (oldVal: any, newVal: any, key: any) => any, ...collections: Array<Partial<T> | Iterable<[string, any]>>): this;
          delete<K extends keyof T>(key: K): this;
          remove<K extends keyof T>(key: K): this;
          clear(): this;
          // Deep persistent changes
          setIn(keyPath: Iterable<any>, value: any): this;
          updateIn(keyPath: Iterable<any>, updater: (value: any) => any): this;
          mergeIn(keyPath: Iterable<any>, ...collections: Array<any>): this;
          mergeDeepIn(keyPath: Iterable<any>, ...collections: Array<any>): this;
          deleteIn(keyPath: Iterable<any>): this;
          removeIn(keyPath: Iterable<any>): this;
          // Conversion to JavaScript types
          toJS(): { [K in keyof T]: any };
          toJSON(): T;
          toObject(): T;
          // Transient changes
          withMutations(mutator: (mutable: this) => any): this;
          asMutable(): this;
          asImmutable(): this;
          // Sequence algorithms
          toSeq(): Seq.Keyed<keyof T, T[keyof T]>;
          [Symbol.iterator](): IterableIterator<[keyof T, T[keyof T]]>;
        }
      }
      export function Record<T>(defaultValues: T, name?: string): Record.Class<T>;
      export module Seq {
        function isSeq(maybeSeq: any): maybeSeq is Seq.Indexed<any> | Seq.Keyed<any, any>;
        function of<T>(...values: Array<T>): Seq.Indexed<T>;
        export module Keyed {}
        export function Keyed<K, V>(collection: Iterable<[K, V]>): Seq.Keyed<K, V>;
        export function Keyed<V>(obj: {[key: string]: V}): Seq.Keyed<string, V>;
        export function Keyed<K, V>(): Seq.Keyed<K, V>;
        export function Keyed(): Seq.Keyed<any, any>;
        export interface Keyed<K, V> extends Seq<K, V>, Collection.Keyed<K, V> {
          toJS(): Object;
          toJSON(): { [key: string]: V };
          toSeq(): this;
          concat<KC, VC>(...collections: Array<Iterable<[KC, VC]>>): Seq.Keyed<K | KC, V | VC>;
          concat<C>(...collections: Array<{[key: string]: C}>): Seq.Keyed<K | string, V | C>;
          map<M>(mapper: (value: V, key: K, iter: this) => M, context?: any): Seq.Keyed<K, M>;
          mapKeys<M>(mapper: (key: K, value: V, iter: this) => M, context?: any): Seq.Keyed<M, V>;
          mapEntries<KM, VM>(mapper: (entry: [K, V], index: number, iter: this) => [KM, VM], context?: any): Seq.Keyed<KM, VM>;
          flatMap<M>(mapper: (value: V, key: K, iter: this) => Iterable<M>, context?: any): Seq.Keyed<any, any>;
          filter<F extends V>(predicate: (value: V, key: K, iter: this) => value is F, context?: any): Seq.Keyed<K, F>;
          filter(predicate: (value: V, key: K, iter: this) => any, context?: any): this;
        }
        module Indexed {
          function of<T>(...values: Array<T>): Seq.Indexed<T>;
        }
        export function Indexed(): Seq.Indexed<any>;
        export function Indexed<T>(): Seq.Indexed<T>;
        export function Indexed<T>(collection: Iterable<T>): Seq.Indexed<T>;
        export interface Indexed<T> extends Seq<number, T>, Collection.Indexed<T> {
          toJS(): Array<any>;
          toJSON(): Array<T>;
          toSeq(): this;
          concat<C>(...valuesOrCollections: Array<Iterable<C> | C>): Seq.Indexed<T | C>;
          map<M>(mapper: (value: T, key: number, iter: this) => M, context?: any): Seq.Indexed<M>;
          flatMap<M>(mapper: (value: T, key: number, iter: this) => Iterable<M>, context?: any): Seq.Indexed<M>;
          filter<F extends T>(predicate: (value: T, index: number, iter: this) => value is F, context?: any): Seq.Indexed<F>;
          filter(predicate: (value: T, index: number, iter: this) => any, context?: any): this;
        }
        export module Set {
          function of<T>(...values: Array<T>): Seq.Set<T>;
        }
        export function Set(): Seq.Set<any>;
        export function Set<T>(): Seq.Set<T>;
        export function Set<T>(collection: Iterable<T>): Seq.Set<T>;
        export interface Set<T> extends Seq<never, T>, Collection.Set<T> {
          toJS(): Array<any>;
          toJSON(): Array<T>;
          toSeq(): this;
          concat<C>(...valuesOrCollections: Array<Iterable<C> | C>): Seq.Set<T | C>;
          map<M>(mapper: (value: T, key: never, iter: this) => M, context?: any): Seq.Set<M>;
          flatMap<M>(mapper: (value: T, key: never, iter: this) => Iterable<M>, context?: any): Seq.Set<M>;
          filter<F extends T>(predicate: (value: T, key: never, iter: this) => value is F, context?: any): Seq.Set<F>;
          filter(predicate: (value: T, key: never, iter: this) => any, context?: any): this;
        }
      }
      export function Seq<S extends Seq<any, any>>(seq: S): S;
      export function Seq<K, V>(collection: Collection.Keyed<K, V>): Seq.Keyed<K, V>;
      export function Seq<T>(collection: Collection.Indexed<T>): Seq.Indexed<T>;
      export function Seq<T>(collection: Collection.Set<T>): Seq.Set<T>;
      export function Seq<T>(collection: Iterable<T>): Seq.Indexed<T>;
      export function Seq<V>(obj: {[key: string]: V}): Seq.Keyed<string, V>;
      export function Seq(): Seq<any, any>;
      export interface Seq<K, V> extends Collection<K, V> {
        readonly size: number | undefined;
        // Force evaluation
        cacheResult(): this;
        // Sequence algorithms
        map<M>(mapper: (value: V, key: K, iter: this) => M, context?: any): Seq<K, M>;
        flatMap<M>(mapper: (value: V, key: K, iter: this) => Iterable<M>, context?: any): Seq<K, M>;
        filter<F extends V>(predicate: (value: V, key: K, iter: this) => value is F, context?: any): Seq<K, F>;
        filter(predicate: (value: V, key: K, iter: this) => any, context?: any): this;
      }
      export module Collection {
        function isKeyed(maybeKeyed: any): maybeKeyed is Collection.Keyed<any, any>;
        function isIndexed(maybeIndexed: any): maybeIndexed is Collection.Indexed<any>;
        function isAssociative(maybeAssociative: any): maybeAssociative is Collection.Keyed<any, any> | Collection.Indexed<any>;
        function isOrdered(maybeOrdered: any): boolean;
        export module Keyed {}
        export function Keyed<K, V>(collection: Iterable<[K, V]>): Collection.Keyed<K, V>;
        export function Keyed<V>(obj: {[key: string]: V}): Collection.Keyed<string, V>;
        export interface Keyed<K, V> extends Collection<K, V> {
                         ~~~~~
!!! error TS2430: Interface 'Keyed<K, V>' incorrectly extends interface 'Collection<K, V>'.
!!! error TS2430:   Types of property 'toSeq' are incompatible.
!!! error TS2430:     Type '() => Keyed<K, V>' is not assignable to type '() => this'.
!!! error TS2430:       Type 'Keyed<K, V>' is not assignable to type 'this'.
          toJS(): Object;
          toJSON(): { [key: string]: V };
          toSeq(): Seq.Keyed<K, V>;
          // Sequence functions
          flip(): this;
          concat<KC, VC>(...collections: Array<Iterable<[KC, VC]>>): Collection.Keyed<K | KC, V | VC>;
          concat<C>(...collections: Array<{[key: string]: C}>): Collection.Keyed<K | string, V | C>;
          map<M>(mapper: (value: V, key: K, iter: this) => M, context?: any): Collection.Keyed<K, M>;
          mapKeys<M>(mapper: (key: K, value: V, iter: this) => M, context?: any): Collection.Keyed<M, V>;
          mapEntries<KM, VM>(mapper: (entry: [K, V], index: number, iter: this) => [KM, VM], context?: any): Collection.Keyed<KM, VM>;
          flatMap<M>(mapper: (value: V, key: K, iter: this) => Iterable<M>, context?: any): Collection.Keyed<any, any>;
          filter<F extends V>(predicate: (value: V, key: K, iter: this) => value is F, context?: any): Collection.Keyed<K, F>;
          filter(predicate: (value: V, key: K, iter: this) => any, context?: any): this;
          [Symbol.iterator](): IterableIterator<[K, V]>;
        }
        export module Indexed {}
        export function Indexed<T>(collection: Iterable<T>): Collection.Indexed<T>;
        export interface Indexed<T> extends Collection<number, T> {
                         ~~~~~~~
!!! error TS2430: Interface 'Indexed<T>' incorrectly extends interface 'Collection<number, T>'.
!!! error TS2430:   Types of property 'toSeq' are incompatible.
!!! error TS2430:     Type '() => Indexed<T>' is not assignable to type '() => this'.
!!! error TS2430:       Type 'Indexed<T>' is not assignable to type 'this'.
          toJS(): Array<any>;
          toJSON(): Array<T>;
          // Reading values
          get<NSV>(index: number, notSetValue: NSV): T | NSV;
          get(index: number): T | undefined;
          // Conversion to Seq
          toSeq(): Seq.Indexed<T>;
          fromEntrySeq(): Seq.Keyed<any, any>;
          // Combination
          interpose(separator: T): this;
          interleave(...collections: Array<Collection<any, T>>): this;
          splice(index: number, removeNum: number, ...values: Array<T>): this;
          zip(...collections: Array<Collection<any, any>>): Collection.Indexed<any>;
          zipWith<U, Z>(zipper: (value: T, otherValue: U) => Z, otherCollection: Collection<any, U>): Collection.Indexed<Z>;
          zipWith<U, V, Z>(zipper: (value: T, otherValue: U, thirdValue: V) => Z, otherCollection: Collection<any, U>, thirdCollection: Collection<any, V>): Collection.Indexed<Z>;
          zipWith<Z>(zipper: (...any: Array<any>) => Z, ...collections: Array<Collection<any, any>>): Collection.Indexed<Z>;
          // Search for value
          indexOf(searchValue: T): number;
          lastIndexOf(searchValue: T): number;
          findIndex(predicate: (value: T, index: number, iter: this) => boolean, context?: any): number;
          findLastIndex(predicate: (value: T, index: number, iter: this) => boolean, context?: any): number;
          // Sequence algorithms
          concat<C>(...valuesOrCollections: Array<Iterable<C> | C>): Collection.Indexed<T | C>;
          map<M>(mapper: (value: T, key: number, iter: this) => M, context?: any): Collection.Indexed<M>;
          flatMap<M>(mapper: (value: T, key: number, iter: this) => Iterable<M>, context?: any): Collection.Indexed<M>;
          filter<F extends T>(predicate: (value: T, index: number, iter: this) => value is F, context?: any): Collection.Indexed<F>;
          filter(predicate: (value: T, index: number, iter: this) => any, context?: any): this;
          [Symbol.iterator](): IterableIterator<T>;
        }
        export module Set {}
        export function Set<T>(collection: Iterable<T>): Collection.Set<T>;
        export interface Set<T> extends Collection<never, T> {
                         ~~~
!!! error TS2430: Interface 'Set<T>' incorrectly extends interface 'Collection<never, T>'.
!!! error TS2430:   Types of property 'toSeq' are incompatible.
!!! error TS2430:     Type '() => Set<T>' is not assignable to type '() => this'.
!!! error TS2430:       Type 'Set<T>' is not assignable to type 'this'.
          toJS(): Array<any>;
          toJSON(): Array<T>;
          toSeq(): Seq.Set<T>;
          // Sequence algorithms
          concat<C>(...valuesOrCollections: Array<Iterable<C> | C>): Collection.Set<T | C>;
          map<M>(mapper: (value: T, key: never, iter: this) => M, context?: any): Collection.Set<M>;
          flatMap<M>(mapper: (value: T, key: never, iter: this) => Iterable<M>, context?: any):  Collection.Set<M>;
          filter<F extends T>(predicate: (value: T, key: never, iter: this) => value is F, context?: any): Collection.Set<F>;
          filter(predicate: (value: T, key: never, iter: this) => any, context?: any): this;
          [Symbol.iterator](): IterableIterator<T>;
        }
      }
      export function Collection<I extends Collection<any, any>>(collection: I): I;
      export function Collection<T>(collection: Iterable<T>): Collection.Indexed<T>;
      export function Collection<V>(obj: {[key: string]: V}): Collection.Keyed<string, V>;
      export interface Collection<K, V> extends ValueObject {
        // Value equality
        equals(other: any): boolean;
        hashCode(): number;
        // Reading values
        get<NSV>(key: K, notSetValue: NSV): V | NSV;
        get(key: K): V | undefined;
        has(key: K): boolean;
        includes(value: V): boolean;
        contains(value: V): boolean;
        first(): V | undefined;
        last(): V | undefined;
        // Reading deep values
        getIn(searchKeyPath: Iterable<any>, notSetValue?: any): any;
        hasIn(searchKeyPath: Iterable<any>): boolean;
        // Persistent changes
        update<R>(updater: (value: this) => R): R;
        // Conversion to JavaScript types
        toJS(): Array<any> | { [key: string]: any };
        toJSON(): Array<V> | { [key: string]: V };
        toArray(): Array<V>;
        toObject(): { [key: string]: V };
        // Conversion to Collections
        toMap(): Map<K, V>;
        toOrderedMap(): OrderedMap<K, V>;
        toSet(): Set<V>;
        toOrderedSet(): OrderedSet<V>;
        toList(): List<V>;
        toStack(): Stack<V>;
        // Conversion to Seq
        toSeq(): this;
        toKeyedSeq(): Seq.Keyed<K, V>;
        toIndexedSeq(): Seq.Indexed<V>;
        toSetSeq(): Seq.Set<V>;
        // Iterators
        keys(): IterableIterator<K>;
        values(): IterableIterator<V>;
        entries(): IterableIterator<[K, V]>;
        // Collections (Seq)
        keySeq(): Seq.Indexed<K>;
        valueSeq(): Seq.Indexed<V>;
        entrySeq(): Seq.Indexed<[K, V]>;
        // Sequence algorithms
        map<M>(mapper: (value: V, key: K, iter: this) => M, context?: any): Collection<K, M>;
        filter<F extends V>(predicate: (value: V, key: K, iter: this) => value is F, context?: any): Collection<K, F>;
        filter(predicate: (value: V, key: K, iter: this) => any, context?: any): this;
        filterNot(predicate: (value: V, key: K, iter: this) => boolean, context?: any): this;
        reverse(): this;
        sort(comparator?: (valueA: V, valueB: V) => number): this;
        sortBy<C>(comparatorValueMapper: (value: V, key: K, iter: this) => C, comparator?: (valueA: C, valueB: C) => number): this;
        groupBy<G>(grouper: (value: V, key: K, iter: this) => G, context?: any): /*Map*/Seq.Keyed<G, /*this*/Collection<K, V>>;
        // Side effects
        forEach(sideEffect: (value: V, key: K, iter: this) => any, context?: any): number;
        // Creating subsets
        slice(begin?: number, end?: number): this;
        rest(): this;
        butLast(): this;
        skip(amount: number): this;
        skipLast(amount: number): this;
        skipWhile(predicate: (value: V, key: K, iter: this) => boolean, context?: any): this;
        skipUntil(predicate: (value: V, key: K, iter: this) => boolean, context?: any): this;
        take(amount: number): this;
        takeLast(amount: number): this;
        takeWhile(predicate: (value: V, key: K, iter: this) => boolean, context?: any): this;
        takeUntil(predicate: (value: V, key: K, iter: this) => boolean, context?: any): this;
        // Combination
        concat(...valuesOrCollections: Array<any>): Collection<any, any>;
        flatten(depth?: number): Collection<any, any>;
        flatten(shallow?: boolean): Collection<any, any>;
        flatMap<M>(mapper: (value: V, key: K, iter: this) => Iterable<M>, context?: any): Collection<K, M>;
        // Reducing a value
        reduce<R>(reducer: (reduction: R, value: V, key: K, iter: this) => R, initialReduction: R, context?: any): R;
        reduce<R>(reducer: (reduction: V | R, value: V, key: K, iter: this) => R): R;
        reduceRight<R>(reducer: (reduction: R, value: V, key: K, iter: this) => R, initialReduction: R, context?: any): R;
        reduceRight<R>(reducer: (reduction: V | R, value: V, key: K, iter: this) => R): R;
        every(predicate: (value: V, key: K, iter: this) => boolean, context?: any): boolean;
        some(predicate: (value: V, key: K, iter: this) => boolean, context?: any): boolean;
        join(separator?: string): string;
        isEmpty(): boolean;
        count(): number;
        count(predicate: (value: V, key: K, iter: this) => boolean, context?: any): number;
        countBy<G>(grouper: (value: V, key: K, iter: this) => G, context?: any): Map<G, number>;
        // Search for value
        find(predicate: (value: V, key: K, iter: this) => boolean, context?: any, notSetValue?: V): V | undefined;
        findLast(predicate: (value: V, key: K, iter: this) => boolean, context?: any, notSetValue?: V): V | undefined;
        findEntry(predicate: (value: V, key: K, iter: this) => boolean, context?: any, notSetValue?: V): [K, V] | undefined;
        findLastEntry(predicate: (value: V, key: K, iter: this) => boolean, context?: any, notSetValue?: V): [K, V] | undefined;
        findKey(predicate: (value: V, key: K, iter: this) => boolean, context?: any): K | undefined;
        findLastKey(predicate: (value: V, key: K, iter: this) => boolean, context?: any): K | undefined;
        keyOf(searchValue: V): K | undefined;
        lastKeyOf(searchValue: V): K | undefined;
        max(comparator?: (valueA: V, valueB: V) => number): V | undefined;
        maxBy<C>(comparatorValueMapper: (value: V, key: K, iter: this) => C, comparator?: (valueA: C, valueB: C) => number): V | undefined;
        min(comparator?: (valueA: V, valueB: V) => number): V | undefined;
        minBy<C>(comparatorValueMapper: (value: V, key: K, iter: this) => C, comparator?: (valueA: C, valueB: C) => number): V | undefined;
        // Comparison
        isSubset(iter: Iterable<V>): boolean;
        isSuperset(iter: Iterable<V>): boolean;
        readonly size: number;
      }
    }
    declare module "immutable" {
      export = Immutable
    }