Index: imaps-frontend/node_modules/immutable/dist/immutable.js.flow
===================================================================
--- imaps-frontend/node_modules/immutable/dist/immutable.js.flow	(revision 0c6b92add4cfaedcb91bcd37b45849f142f7d152)
+++ imaps-frontend/node_modules/immutable/dist/immutable.js.flow	(revision 0c6b92add4cfaedcb91bcd37b45849f142f7d152)
@@ -0,0 +1,2414 @@
+/**
+ * This file provides type definitions for use with the Flow type checker.
+ *
+ * An important caveat when using these definitions is that the types for
+ * `Collection.Keyed`, `Collection.Indexed`, `Seq.Keyed`, and so on are stubs.
+ * When referring to those types, you can get the proper definitions by
+ * importing the types `KeyedCollection`, `IndexedCollection`, `KeyedSeq`, etc.
+ * For example,
+ *
+ *     import { Seq } from 'immutable'
+ *     import type { IndexedCollection, IndexedSeq } from 'immutable'
+ *
+ *     const someSeq: IndexedSeq<number> = Seq.Indexed.of(1, 2, 3)
+ *
+ *     function takesASeq<T, TS: IndexedCollection<T>>(iter: TS): TS {
+ *       return iter.butLast()
+ *     }
+ *
+ *     takesASeq(someSeq)
+ *
+ * @flow strict
+ */
+
+// Helper type that represents plain objects allowed as arguments to
+// some constructors and functions.
+type PlainObjInput<K, V> = { +[key: K]: V, __proto__: null };
+
+type K<T> = $Keys<T>;
+
+// Helper types to extract the "keys" and "values" use by the *In() methods.
+type $KeyOf<C> = $Call<
+  (<K>(?_Collection<K, mixed>) => K) &
+    (<T>(?$ReadOnlyArray<T>) => number) &
+    (<T>(?RecordInstance<T> | T) => $Keys<T>) &
+    (<T: Object>(T) => $Keys<T>),
+  C
+>;
+
+type $ValOf<C, K = $KeyOf<C>> = $Call<
+  (<V>(?_Collection<any, V>) => V) &
+    (<T>(?$ReadOnlyArray<T>) => T) &
+    (<T, K: $Keys<T>>(?RecordInstance<T> | T, K) => $ElementType<T, K>) &
+    (<T: Object>(T) => $Values<T>),
+  C,
+  K
+>;
+
+type $IterableOf<C> = $Call<
+  (<V: Array<any> | IndexedCollection<any> | SetCollection<any>>(
+    V
+  ) => Iterable<$ValOf<V>>) &
+    (<
+      V:
+        | KeyedCollection<any, any>
+        | RecordInstance<any>
+        | PlainObjInput<any, any>
+    >(
+      V
+    ) => Iterable<[$KeyOf<V>, $ValOf<V>]>),
+  C
+>;
+
+const PairSorting: $ReadOnly<{ LeftThenRight: number, RightThenLeft: number }> =
+  {
+    LeftThenRight: -1,
+    RightThenLeft: +1,
+  };
+
+type Comparator<T> = (left: T, right: T) => number;
+
+declare class _Collection<K, +V> implements ValueObject {
+  equals(other: mixed): boolean;
+  hashCode(): number;
+  get(key: K, ..._: []): V | void;
+  get<NSV>(key: K, notSetValue: NSV): V | NSV;
+  has(key: K): boolean;
+  includes(value: V): boolean;
+  contains(value: V): boolean;
+  first(): V | void;
+  first<NSV>(notSetValue: NSV): V | NSV;
+  last(): V | void;
+  last<NSV>(notSetValue: NSV): V | NSV;
+
+  hasIn(keyPath: Iterable<mixed>): boolean;
+
+  getIn(keyPath: [], notSetValue?: mixed): this;
+  getIn<NSV>(keyPath: [K], notSetValue: NSV): V | NSV;
+  getIn<NSV, K2: $KeyOf<V>>(
+    keyPath: [K, K2],
+    notSetValue: NSV
+  ): $ValOf<V, K2> | NSV;
+  getIn<NSV, K2: $KeyOf<V>, K3: $KeyOf<$ValOf<V, K2>>>(
+    keyPath: [K, K2, K3],
+    notSetValue: NSV
+  ): $ValOf<$ValOf<V, K2>, K3> | NSV;
+  getIn<
+    NSV,
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>
+  >(
+    keyPath: [K, K2, K3, K4],
+    notSetValue: NSV
+  ): $ValOf<$ValOf<$ValOf<V, K2>, K3>, K4> | NSV;
+  getIn<
+    NSV,
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>>
+  >(
+    keyPath: [K, K2, K3, K4, K5],
+    notSetValue: NSV
+  ): $ValOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>, K5> | NSV;
+
+  update<U>(updater: (value: this) => U): U;
+
+  toJS(): Array<any> | { [key: string]: mixed };
+  toJSON(): Array<V> | { [key: string]: V };
+  toArray(): Array<V> | Array<[K, V]>;
+  toObject(): { [key: string]: V };
+  toMap(): Map<K, V>;
+  toOrderedMap(): OrderedMap<K, V>;
+  toSet(): Set<V>;
+  toOrderedSet(): OrderedSet<V>;
+  toList(): List<V>;
+  toStack(): Stack<V>;
+  toSeq(): Seq<K, V>;
+  toKeyedSeq(): KeyedSeq<K, V>;
+  toIndexedSeq(): IndexedSeq<V>;
+  toSetSeq(): SetSeq<V>;
+
+  keys(): Iterator<K>;
+  values(): Iterator<V>;
+  entries(): Iterator<[K, V]>;
+
+  keySeq(): IndexedSeq<K>;
+  valueSeq(): IndexedSeq<V>;
+  entrySeq(): IndexedSeq<[K, V]>;
+
+  reverse(): this;
+  sort(comparator?: Comparator<V>): this;
+
+  sortBy<C>(
+    comparatorValueMapper: (value: V, key: K, iter: this) => C,
+    comparator?: Comparator<C>
+  ): this;
+
+  groupBy<G>(
+    grouper: (value: V, key: K, iter: this) => G,
+    context?: mixed
+  ): KeyedSeq<G, this>;
+
+  forEach(
+    sideEffect: (value: V, key: K, iter: this) => any,
+    context?: mixed
+  ): number;
+
+  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) => mixed,
+    context?: mixed
+  ): this;
+  skipUntil(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): this;
+  take(amount: number): this;
+  takeLast(amount: number): this;
+  takeWhile(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): this;
+  takeUntil(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): this;
+
+  filterNot(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): this;
+
+  reduce<R>(
+    reducer: (reduction: R, value: V, key: K, iter: this) => R,
+    initialReduction: R,
+    context?: mixed
+  ): 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?: mixed
+  ): R;
+  reduceRight<R>(
+    reducer: (reduction: V | R, value: V, key: K, iter: this) => R
+  ): R;
+
+  every(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): boolean;
+  some(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): boolean;
+  join(separator?: string): string;
+  isEmpty(): boolean;
+  count(
+    predicate?: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): number;
+  countBy<G>(
+    grouper: (value: V, key: K, iter: this) => G,
+    context?: mixed
+  ): Map<G, number>;
+
+  find(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed,
+    notSetValue?: V
+  ): V | void;
+  findLast(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed,
+    notSetValue?: V
+  ): V | void;
+
+  findEntry(predicate: (value: V, key: K, iter: this) => mixed): [K, V] | void;
+  findLastEntry(
+    predicate: (value: V, key: K, iter: this) => mixed
+  ): [K, V] | void;
+
+  findKey(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): K | void;
+  findLastKey(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): K | void;
+
+  keyOf(searchValue: V): K | void;
+  lastKeyOf(searchValue: V): K | void;
+
+  max(comparator?: Comparator<V>): V;
+  maxBy<C>(
+    comparatorValueMapper: (value: V, key: K, iter: this) => C,
+    comparator?: Comparator<C>
+  ): V;
+  min(comparator?: Comparator<V>): V;
+  minBy<C>(
+    comparatorValueMapper: (value: V, key: K, iter: this) => C,
+    comparator?: Comparator<C>
+  ): V;
+
+  isSubset(iter: Iterable<V>): boolean;
+  isSuperset(iter: Iterable<V>): boolean;
+}
+
+declare function isImmutable(
+  maybeImmutable: mixed
+): boolean %checks(maybeImmutable instanceof Collection);
+declare function isCollection(
+  maybeCollection: mixed
+): boolean %checks(maybeCollection instanceof Collection);
+declare function isKeyed(
+  maybeKeyed: mixed
+): boolean %checks(maybeKeyed instanceof KeyedCollection);
+declare function isIndexed(
+  maybeIndexed: mixed
+): boolean %checks(maybeIndexed instanceof IndexedCollection);
+declare function isAssociative(
+  maybeAssociative: mixed
+): boolean %checks(maybeAssociative instanceof KeyedCollection ||
+  maybeAssociative instanceof IndexedCollection);
+declare function isOrdered(
+  maybeOrdered: mixed
+): boolean %checks(maybeOrdered instanceof IndexedCollection ||
+  maybeOrdered instanceof OrderedMap ||
+  maybeOrdered instanceof OrderedSet);
+declare function isValueObject(maybeValue: mixed): boolean;
+
+declare function isSeq(maybeSeq: any): boolean %checks(maybeSeq instanceof Seq);
+declare function isList(maybeList: any): boolean %checks(maybeList instanceof
+  List);
+declare function isMap(maybeMap: any): boolean %checks(maybeMap instanceof Map);
+declare function isOrderedMap(
+  maybeOrderedMap: any
+): boolean %checks(maybeOrderedMap instanceof OrderedMap);
+declare function isStack(maybeStack: any): boolean %checks(maybeStack instanceof
+  Stack);
+declare function isSet(maybeSet: any): boolean %checks(maybeSet instanceof Set);
+declare function isOrderedSet(
+  maybeOrderedSet: any
+): boolean %checks(maybeOrderedSet instanceof OrderedSet);
+declare function isRecord(
+  maybeRecord: any
+): boolean %checks(maybeRecord instanceof Record);
+
+declare interface ValueObject {
+  equals(other: mixed): boolean;
+  hashCode(): number;
+}
+
+declare class Collection<K, +V> extends _Collection<K, V> {
+  static Keyed: typeof KeyedCollection;
+  static Indexed: typeof IndexedCollection;
+  static Set: typeof SetCollection;
+
+  static isCollection: typeof isCollection;
+  static isKeyed: typeof isKeyed;
+  static isIndexed: typeof isIndexed;
+  static isAssociative: typeof isAssociative;
+  static isOrdered: typeof isOrdered;
+}
+
+declare class KeyedCollection<K, +V> extends Collection<K, V> {
+  static <K, V>(
+    values?: Iterable<[K, V]> | PlainObjInput<K, V>
+  ): KeyedCollection<K, V>;
+
+  toJS(): { [key: string]: mixed };
+  toJSON(): { [key: string]: V };
+  toArray(): Array<[K, V]>;
+  @@iterator(): Iterator<[K, V]>;
+  toSeq(): KeyedSeq<K, V>;
+  flip(): KeyedCollection<V, K>;
+
+  concat<KC, VC>(
+    ...iters: Array<Iterable<[KC, VC]> | PlainObjInput<KC, VC>>
+  ): KeyedCollection<K | KC, V | VC>;
+
+  filter(predicate: typeof Boolean): KeyedCollection<K, $NonMaybeType<V>>;
+  filter(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): KeyedCollection<K, V>;
+
+  partition(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: V, key: K, iter: this) => M,
+    context?: mixed
+  ): KeyedCollection<K, M>;
+
+  mapKeys<M>(
+    mapper: (key: K, value: V, iter: this) => M,
+    context?: mixed
+  ): KeyedCollection<M, V>;
+
+  mapEntries<KM, VM>(
+    mapper: (entry: [K, V], index: number, iter: this) => [KM, VM],
+    context?: mixed
+  ): KeyedCollection<KM, VM>;
+
+  flatMap<KM, VM>(
+    mapper: (value: V, key: K, iter: this) => Iterable<[KM, VM]>,
+    context?: mixed
+  ): KeyedCollection<KM, VM>;
+
+  flatten(depth?: number): KeyedCollection<any, any>;
+  flatten(shallow?: boolean): KeyedCollection<any, any>;
+}
+
+Collection.Keyed = KeyedCollection;
+
+declare class IndexedCollection<+T> extends Collection<number, T> {
+  static <T>(iter?: Iterable<T>): IndexedCollection<T>;
+
+  toJS(): Array<mixed>;
+  toJSON(): Array<T>;
+  toArray(): Array<T>;
+  @@iterator(): Iterator<T>;
+  toSeq(): IndexedSeq<T>;
+  fromEntrySeq<K, V>(): KeyedSeq<K, V>;
+  interpose(separator: T): this;
+  interleave(...collections: Iterable<T>[]): this;
+  splice(index: number, removeNum: number, ...values: T[]): this;
+
+  zip<A>(a: Iterable<A>, ..._: []): IndexedCollection<[T, A]>;
+  zip<A, B>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): IndexedCollection<[T, A, B]>;
+  zip<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): IndexedCollection<[T, A, B, C]>;
+  zip<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): IndexedCollection<[T, A, B, C, D]>;
+  zip<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): IndexedCollection<[T, A, B, C, D, E]>;
+
+  zipAll<A>(a: Iterable<A>, ..._: []): IndexedCollection<[T | void, A | void]>;
+  zipAll<A, B>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): IndexedCollection<[T | void, A | void, B | void]>;
+  zipAll<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): IndexedCollection<[T | void, A | void, B | void, C | void]>;
+  zipAll<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): IndexedCollection<[T | void, A | void, B | void, C | void, D | void]>;
+  zipAll<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): IndexedCollection<
+    [T | void, A | void, B | void, C | void, D | void, E | void]
+  >;
+
+  zipWith<A, R>(
+    zipper: (value: T, a: A) => R,
+    a: Iterable<A>,
+    ..._: []
+  ): IndexedCollection<R>;
+  zipWith<A, B, R>(
+    zipper: (value: T, a: A, b: B) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): IndexedCollection<R>;
+  zipWith<A, B, C, R>(
+    zipper: (value: T, a: A, b: B, c: C) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): IndexedCollection<R>;
+  zipWith<A, B, C, D, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): IndexedCollection<R>;
+  zipWith<A, B, C, D, E, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D, e: E) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): IndexedCollection<R>;
+
+  indexOf(searchValue: T): number;
+  lastIndexOf(searchValue: T): number;
+  findIndex(
+    predicate: (value: T, index: number, iter: this) => mixed,
+    context?: mixed
+  ): number;
+  findLastIndex(
+    predicate: (value: T, index: number, iter: this) => mixed,
+    context?: mixed
+  ): number;
+
+  concat<C>(...iters: Array<Iterable<C> | C>): IndexedCollection<T | C>;
+
+  filter(predicate: typeof Boolean): IndexedCollection<$NonMaybeType<T>>;
+  filter(
+    predicate: (value: T, index: number, iter: this) => mixed,
+    context?: mixed
+  ): IndexedCollection<T>;
+
+  partition(
+    predicate: (value: T, index: number, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: T, index: number, iter: this) => M,
+    context?: mixed
+  ): IndexedCollection<M>;
+
+  flatMap<M>(
+    mapper: (value: T, index: number, iter: this) => Iterable<M>,
+    context?: mixed
+  ): IndexedCollection<M>;
+
+  flatten(depth?: number): IndexedCollection<any>;
+  flatten(shallow?: boolean): IndexedCollection<any>;
+}
+
+declare class SetCollection<+T> extends Collection<T, T> {
+  static <T>(iter?: Iterable<T>): SetCollection<T>;
+
+  toJS(): Array<mixed>;
+  toJSON(): Array<T>;
+  toArray(): Array<T>;
+  @@iterator(): Iterator<T>;
+  toSeq(): SetSeq<T>;
+
+  concat<U>(...collections: Iterable<U>[]): SetCollection<T | U>;
+
+  // `filter`, `map` and `flatMap` cannot be defined further up the hierarchy,
+  // because the implementation for `KeyedCollection` allows the value type to
+  // change without constraining the key type. That does not work for
+  // `SetCollection` - the value and key types *must* match.
+  filter(predicate: typeof Boolean): SetCollection<$NonMaybeType<T>>;
+  filter(
+    predicate: (value: T, value: T, iter: this) => mixed,
+    context?: mixed
+  ): SetCollection<T>;
+
+  partition(
+    predicate: (value: T, value: T, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: T, value: T, iter: this) => M,
+    context?: mixed
+  ): SetCollection<M>;
+
+  flatMap<M>(
+    mapper: (value: T, value: T, iter: this) => Iterable<M>,
+    context?: mixed
+  ): SetCollection<M>;
+
+  flatten(depth?: number): SetCollection<any>;
+  flatten(shallow?: boolean): SetCollection<any>;
+}
+
+declare function isSeq(maybeSeq: mixed): boolean %checks(maybeSeq instanceof
+  Seq);
+declare class Seq<K, +V> extends _Collection<K, V> {
+  static Keyed: typeof KeyedSeq;
+  static Indexed: typeof IndexedSeq;
+  static Set: typeof SetSeq;
+
+  static <K, V>(values: KeyedSeq<K, V>): KeyedSeq<K, V>;
+  static <T>(values: SetSeq<T>): SetSeq<K, V>;
+  static <T>(values: Iterable<T>): IndexedSeq<T>;
+  static <K, V>(values?: PlainObjInput<K, V>): KeyedSeq<K, V>;
+
+  static isSeq: typeof isSeq;
+
+  size: number | void;
+  cacheResult(): this;
+  toSeq(): this;
+}
+
+declare class KeyedSeq<K, +V> extends Seq<K, V> mixins KeyedCollection<K, V> {
+  static <K, V>(
+    values?: Iterable<[K, V]> | PlainObjInput<K, V>
+  ): KeyedSeq<K, V>;
+
+  // Override specialized return types
+  flip(): KeyedSeq<V, K>;
+
+  concat<KC, VC>(
+    ...iters: Array<Iterable<[KC, VC]> | PlainObjInput<KC, VC>>
+  ): KeyedSeq<K | KC, V | VC>;
+
+  filter(predicate: typeof Boolean): KeyedSeq<K, $NonMaybeType<V>>;
+  filter(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): KeyedSeq<K, V>;
+
+  partition(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: V, key: K, iter: this) => M,
+    context?: mixed
+  ): KeyedSeq<K, M>;
+
+  mapKeys<M>(
+    mapper: (key: K, value: V, iter: this) => M,
+    context?: mixed
+  ): KeyedSeq<M, V>;
+
+  mapEntries<KM, VM>(
+    mapper: (entry: [K, V], index: number, iter: this) => [KM, VM],
+    context?: mixed
+  ): KeyedSeq<KM, VM>;
+
+  flatMap<KM, VM>(
+    mapper: (value: V, key: K, iter: this) => Iterable<[KM, VM]>,
+    context?: mixed
+  ): KeyedSeq<KM, VM>;
+
+  flatten(depth?: number): KeyedSeq<any, any>;
+  flatten(shallow?: boolean): KeyedSeq<any, any>;
+}
+
+declare class IndexedSeq<+T>
+  extends Seq<number, T>
+  mixins IndexedCollection<T>
+{
+  static <T>(values?: Iterable<T>): IndexedSeq<T>;
+
+  static of<T>(...values: T[]): IndexedSeq<T>;
+
+  // Override specialized return types
+
+  concat<C>(...iters: Array<Iterable<C> | C>): IndexedSeq<T | C>;
+
+  filter(predicate: typeof Boolean): IndexedSeq<$NonMaybeType<T>>;
+  filter(
+    predicate: (value: T, index: number, iter: this) => mixed,
+    context?: mixed
+  ): IndexedSeq<T>;
+
+  partition(
+    predicate: (value: T, index: number, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: T, index: number, iter: this) => M,
+    context?: mixed
+  ): IndexedSeq<M>;
+
+  flatMap<M>(
+    mapper: (value: T, index: number, iter: this) => Iterable<M>,
+    context?: mixed
+  ): IndexedSeq<M>;
+
+  flatten(depth?: number): IndexedSeq<any>;
+  flatten(shallow?: boolean): IndexedSeq<any>;
+
+  zip<A>(a: Iterable<A>, ..._: []): IndexedSeq<[T, A]>;
+  zip<A, B>(a: Iterable<A>, b: Iterable<B>, ..._: []): IndexedSeq<[T, A, B]>;
+  zip<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): IndexedSeq<[T, A, B, C]>;
+  zip<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): IndexedSeq<[T, A, B, C, D]>;
+  zip<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): IndexedSeq<[T, A, B, C, D, E]>;
+
+  zipAll<A>(a: Iterable<A>, ..._: []): IndexedSeq<[T | void, A | void]>;
+  zipAll<A, B>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): IndexedSeq<[T | void, A | void, B | void]>;
+  zipAll<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): IndexedSeq<[T | void, A | void, B | void, C | void]>;
+  zipAll<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): IndexedSeq<[T | void, A | void, B | void, C | void, D | void]>;
+  zipAll<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): IndexedSeq<[T | void, A | void, B | void, C | void, D | void, E | void]>;
+
+  zipWith<A, R>(
+    zipper: (value: T, a: A) => R,
+    a: Iterable<A>,
+    ..._: []
+  ): IndexedSeq<R>;
+  zipWith<A, B, R>(
+    zipper: (value: T, a: A, b: B) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): IndexedSeq<R>;
+  zipWith<A, B, C, R>(
+    zipper: (value: T, a: A, b: B, c: C) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): IndexedSeq<R>;
+  zipWith<A, B, C, D, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): IndexedSeq<R>;
+  zipWith<A, B, C, D, E, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D, e: E) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): IndexedSeq<R>;
+}
+
+declare class SetSeq<+T> extends Seq<T, T> mixins SetCollection<T> {
+  static <T>(values?: Iterable<T>): SetSeq<T>;
+
+  static of<T>(...values: T[]): SetSeq<T>;
+
+  // Override specialized return types
+
+  concat<U>(...collections: Iterable<U>[]): SetSeq<T | U>;
+
+  filter(predicate: typeof Boolean): SetSeq<$NonMaybeType<T>>;
+  filter(
+    predicate: (value: T, value: T, iter: this) => mixed,
+    context?: mixed
+  ): SetSeq<T>;
+
+  partition(
+    predicate: (value: T, value: T, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: T, value: T, iter: this) => M,
+    context?: mixed
+  ): SetSeq<M>;
+
+  flatMap<M>(
+    mapper: (value: T, value: T, iter: this) => Iterable<M>,
+    context?: mixed
+  ): SetSeq<M>;
+
+  flatten(depth?: number): SetSeq<any>;
+  flatten(shallow?: boolean): SetSeq<any>;
+}
+
+declare class UpdatableInCollection<K, +V> {
+  setIn<S>(keyPath: [], value: S): S;
+  setIn(keyPath: [K], value: V): this;
+  setIn<K2: $KeyOf<V>, S: $ValOf<V, K2>>(keyPath: [K, K2], value: S): this;
+  setIn<K2: $KeyOf<V>, K3: $KeyOf<$ValOf<V, K2>>, S: $ValOf<$ValOf<V, K2>, K3>>(
+    keyPath: [K, K2, K3],
+    value: S
+  ): this;
+  setIn<
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>,
+    S: $ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>
+  >(
+    keyPath: [K, K2, K3, K4],
+    value: S
+  ): this;
+  setIn<
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>>,
+    S: $ValOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>, K5>
+  >(
+    keyPath: [K, K2, K3, K4, K5],
+    value: S
+  ): this;
+
+  deleteIn(keyPath: []): void;
+  deleteIn(keyPath: [K]): this;
+  deleteIn<K2: $KeyOf<V>>(keyPath: [K, K2]): this;
+  deleteIn<K2: $KeyOf<V>, K3: $KeyOf<$ValOf<V, K2>>>(
+    keyPath: [K, K2, K3]
+  ): this;
+  deleteIn<
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>
+  >(
+    keyPath: [K, K2, K3, K4]
+  ): this;
+  deleteIn<
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>>
+  >(
+    keyPath: [K, K2, K3, K4, K5]
+  ): this;
+
+  removeIn(keyPath: []): void;
+  removeIn(keyPath: [K]): this;
+  removeIn<K2: $KeyOf<V>>(keyPath: [K, K2]): this;
+  removeIn<K2: $KeyOf<V>, K3: $KeyOf<$ValOf<V, K2>>>(
+    keyPath: [K, K2, K3]
+  ): this;
+  removeIn<
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>
+  >(
+    keyPath: [K, K2, K3, K4]
+  ): this;
+  removeIn<
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>>
+  >(
+    keyPath: [K, K2, K3, K4, K5]
+  ): this;
+
+  updateIn<U>(keyPath: [], notSetValue: mixed, updater: (value: this) => U): U;
+  updateIn<U>(keyPath: [], updater: (value: this) => U): U;
+  updateIn<NSV>(keyPath: [K], notSetValue: NSV, updater: (value: V) => V): this;
+  updateIn(keyPath: [K], updater: (value: V) => V): this;
+  updateIn<NSV, K2: $KeyOf<V>, S: $ValOf<V, K2>>(
+    keyPath: [K, K2],
+    notSetValue: NSV,
+    updater: (value: $ValOf<V, K2> | NSV) => S
+  ): this;
+  updateIn<K2: $KeyOf<V>, S: $ValOf<V, K2>>(
+    keyPath: [K, K2],
+    updater: (value: $ValOf<V, K2>) => S
+  ): this;
+  updateIn<
+    NSV,
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    S: $ValOf<$ValOf<V, K2>, K3>
+  >(
+    keyPath: [K, K2, K3],
+    notSetValue: NSV,
+    updater: (value: $ValOf<$ValOf<V, K2>, K3> | NSV) => S
+  ): this;
+  updateIn<
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    S: $ValOf<$ValOf<V, K2>, K3>
+  >(
+    keyPath: [K, K2, K3],
+    updater: (value: $ValOf<$ValOf<V, K2>, K3>) => S
+  ): this;
+  updateIn<
+    NSV,
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>,
+    S: $ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>
+  >(
+    keyPath: [K, K2, K3, K4],
+    notSetValue: NSV,
+    updater: (value: $ValOf<$ValOf<$ValOf<V, K2>, K3>, K4> | NSV) => S
+  ): this;
+  updateIn<
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>,
+    S: $ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>
+  >(
+    keyPath: [K, K2, K3, K4],
+    updater: (value: $ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>) => S
+  ): this;
+  updateIn<
+    NSV,
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>>,
+    S: $ValOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>, K5>
+  >(
+    keyPath: [K, K2, K3, K4, K5],
+    notSetValue: NSV,
+    updater: (
+      value: $ValOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>, K5> | NSV
+    ) => S
+  ): this;
+  updateIn<
+    K2: $KeyOf<V>,
+    K3: $KeyOf<$ValOf<V, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<V, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>>,
+    S: $ValOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>, K5>
+  >(
+    keyPath: [K, K2, K3, K4, K5],
+    updater: (value: $ValOf<$ValOf<$ValOf<$ValOf<V, K2>, K3>, K4>, K5>) => S
+  ): this;
+}
+
+declare function isList(maybeList: mixed): boolean %checks(maybeList instanceof
+  List);
+declare class List<+T>
+  extends IndexedCollection<T>
+  mixins UpdatableInCollection<number, T>
+{
+  static <T>(collection?: Iterable<T>): List<T>;
+
+  static of<T>(...values: T[]): List<T>;
+
+  static isList: typeof isList;
+
+  size: number;
+
+  set<U>(index: number, value: U): List<T | U>;
+  delete(index: number): this;
+  remove(index: number): this;
+  insert<U>(index: number, value: U): List<T | U>;
+  clear(): this;
+  push<U>(...values: U[]): List<T | U>;
+  pop(): this;
+  unshift<U>(...values: U[]): List<T | U>;
+  shift(): this;
+
+  update<U>(updater: (value: this) => U): U;
+  update<U>(index: number, updater: (value: T) => U): List<T | U>;
+  update<U>(
+    index: number,
+    notSetValue: U,
+    updater: (value: T) => U
+  ): List<T | U>;
+
+  merge<U>(...collections: Iterable<U>[]): List<T | U>;
+
+  setSize(size: number): this;
+
+  mergeIn(keyPath: Iterable<mixed>, ...collections: Iterable<mixed>[]): this;
+  mergeDeepIn(
+    keyPath: Iterable<mixed>,
+    ...collections: Iterable<mixed>[]
+  ): this;
+
+  withMutations(mutator: (mutable: this) => mixed): this;
+  asMutable(): this;
+  wasAltered(): boolean;
+  asImmutable(): this;
+
+  // Override specialized return types
+
+  concat<C>(...iters: Array<Iterable<C> | C>): List<T | C>;
+
+  filter(predicate: typeof Boolean): List<$NonMaybeType<T>>;
+  filter(
+    predicate: (value: T, index: number, iter: this) => mixed,
+    context?: mixed
+  ): List<T>;
+
+  partition(
+    predicate: (value: T, index: number, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: T, index: number, iter: this) => M,
+    context?: mixed
+  ): List<M>;
+
+  flatMap<M>(
+    mapper: (value: T, index: number, iter: this) => Iterable<M>,
+    context?: mixed
+  ): List<M>;
+
+  flatten(depth?: number): List<any>;
+  flatten(shallow?: boolean): List<any>;
+
+  zip<A>(a: Iterable<A>, ..._: []): List<[T, A]>;
+  zip<A, B>(a: Iterable<A>, b: Iterable<B>, ..._: []): List<[T, A, B]>;
+  zip<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): List<[T, A, B, C]>;
+  zip<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): List<[T, A, B, C, D]>;
+  zip<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): List<[T, A, B, C, D, E]>;
+
+  zipAll<A>(a: Iterable<A>, ..._: []): List<[T | void, A | void]>;
+  zipAll<A, B>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): List<[T | void, A | void, B | void]>;
+  zipAll<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): List<[T | void, A | void, B | void, C | void]>;
+  zipAll<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): List<[T | void, A | void, B | void, C | void, D | void]>;
+  zipAll<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): List<[T | void, A | void, B | void, C | void, D | void, E | void]>;
+
+  zipWith<A, R>(
+    zipper: (value: T, a: A) => R,
+    a: Iterable<A>,
+    ..._: []
+  ): List<R>;
+  zipWith<A, B, R>(
+    zipper: (value: T, a: A, b: B) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): List<R>;
+  zipWith<A, B, C, R>(
+    zipper: (value: T, a: A, b: B, c: C) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): List<R>;
+  zipWith<A, B, C, D, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): List<R>;
+  zipWith<A, B, C, D, E, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D, e: E) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): List<R>;
+}
+
+declare function isMap(maybeMap: mixed): boolean %checks(maybeMap instanceof
+  Map);
+declare class Map<K, +V>
+  extends KeyedCollection<K, V>
+  mixins UpdatableInCollection<K, V>
+{
+  static <K, V>(values?: Iterable<[K, V]> | PlainObjInput<K, V>): Map<K, V>;
+
+  static isMap: typeof isMap;
+
+  size: number;
+
+  set<K_, V_>(key: K_, value: V_): Map<K | K_, V | V_>;
+  delete(key: K): this;
+  remove(key: K): this;
+  clear(): this;
+
+  deleteAll(keys: Iterable<K>): Map<K, V>;
+  removeAll(keys: Iterable<K>): Map<K, V>;
+
+  update<U>(updater: (value: this) => U): U;
+  update<V_>(key: K, updater: (value: V) => V_): Map<K, V | V_>;
+  update<V_>(
+    key: K,
+    notSetValue: V_,
+    updater: (value: V) => V_
+  ): Map<K, V | V_>;
+
+  merge<K_, V_>(
+    ...collections: (Iterable<[K_, V_]> | PlainObjInput<K_, V_>)[]
+  ): Map<K | K_, V | V_>;
+  concat<K_, V_>(
+    ...collections: (Iterable<[K_, V_]> | PlainObjInput<K_, V_>)[]
+  ): Map<K | K_, V | V_>;
+
+  mergeWith<K_, W, X>(
+    merger: (oldVal: V, newVal: W, key: K) => X,
+    ...collections: (Iterable<[K_, W]> | PlainObjInput<K_, W>)[]
+  ): Map<K | K_, V | W | X>;
+
+  mergeDeep<K_, V_>(
+    ...collections: (Iterable<[K_, V_]> | PlainObjInput<K_, V_>)[]
+  ): Map<K | K_, V | V_>;
+
+  mergeDeepWith<K_, V_>(
+    merger: (oldVal: any, newVal: any, key: any) => mixed,
+    ...collections: (Iterable<[K_, V_]> | PlainObjInput<K_, V_>)[]
+  ): Map<K | K_, V | V_>;
+
+  mergeIn(
+    keyPath: Iterable<mixed>,
+    ...collections: (Iterable<mixed> | PlainObjInput<mixed, mixed>)[]
+  ): this;
+  mergeDeepIn(
+    keyPath: Iterable<mixed>,
+    ...collections: (Iterable<mixed> | PlainObjInput<mixed, mixed>)[]
+  ): this;
+
+  withMutations(mutator: (mutable: this) => mixed): this;
+  asMutable(): this;
+  wasAltered(): boolean;
+  asImmutable(): this;
+
+  // Override specialized return types
+
+  flip(): Map<V, K>;
+
+  filter(predicate: typeof Boolean): Map<K, $NonMaybeType<V>>;
+  filter(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): Map<K, V>;
+
+  partition(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: V, key: K, iter: this) => M,
+    context?: mixed
+  ): Map<K, M>;
+
+  mapKeys<M>(
+    mapper: (key: K, value: V, iter: this) => M,
+    context?: mixed
+  ): Map<M, V>;
+
+  mapEntries<KM, VM>(
+    mapper: (entry: [K, V], index: number, iter: this) => [KM, VM],
+    context?: mixed
+  ): Map<KM, VM>;
+
+  flatMap<KM, VM>(
+    mapper: (value: V, key: K, iter: this) => Iterable<[KM, VM]>,
+    context?: mixed
+  ): Map<KM, VM>;
+
+  flatten(depth?: number): Map<any, any>;
+  flatten(shallow?: boolean): Map<any, any>;
+}
+
+declare function isOrderedMap(
+  maybeOrderedMap: mixed
+): boolean %checks(maybeOrderedMap instanceof OrderedMap);
+declare class OrderedMap<K, +V>
+  extends Map<K, V>
+  mixins UpdatableInCollection<K, V>
+{
+  static <K, V>(
+    values?: Iterable<[K, V]> | PlainObjInput<K, V>
+  ): OrderedMap<K, V>;
+
+  static isOrderedMap: typeof isOrderedMap;
+
+  size: number;
+
+  set<K_, V_>(key: K_, value: V_): OrderedMap<K | K_, V | V_>;
+  delete(key: K): this;
+  remove(key: K): this;
+  clear(): this;
+
+  update<U>(updater: (value: this) => U): U;
+  update<V_>(key: K, updater: (value: V) => V_): OrderedMap<K, V | V_>;
+  update<V_>(
+    key: K,
+    notSetValue: V_,
+    updater: (value: V) => V_
+  ): OrderedMap<K, V | V_>;
+
+  merge<K_, V_>(
+    ...collections: (Iterable<[K_, V_]> | PlainObjInput<K_, V_>)[]
+  ): OrderedMap<K | K_, V | V_>;
+  concat<K_, V_>(
+    ...collections: (Iterable<[K_, V_]> | PlainObjInput<K_, V_>)[]
+  ): OrderedMap<K | K_, V | V_>;
+
+  mergeWith<K_, W, X>(
+    merger: (oldVal: V, newVal: W, key: K) => X,
+    ...collections: (Iterable<[K_, W]> | PlainObjInput<K_, W>)[]
+  ): OrderedMap<K | K_, V | W | X>;
+
+  mergeDeep<K_, V_>(
+    ...collections: (Iterable<[K_, V_]> | PlainObjInput<K_, V_>)[]
+  ): OrderedMap<K | K_, V | V_>;
+
+  mergeDeepWith<K_, V_>(
+    merger: (oldVal: any, newVal: any, key: any) => mixed,
+    ...collections: (Iterable<[K_, V_]> | PlainObjInput<K_, V_>)[]
+  ): OrderedMap<K | K_, V | V_>;
+
+  mergeIn(
+    keyPath: Iterable<mixed>,
+    ...collections: (Iterable<mixed> | PlainObjInput<mixed, mixed>)[]
+  ): this;
+  mergeDeepIn(
+    keyPath: Iterable<mixed>,
+    ...collections: (Iterable<mixed> | PlainObjInput<mixed, mixed>)[]
+  ): this;
+
+  withMutations(mutator: (mutable: this) => mixed): this;
+  asMutable(): this;
+  wasAltered(): boolean;
+  asImmutable(): this;
+
+  // Override specialized return types
+
+  flip(): OrderedMap<V, K>;
+
+  filter(predicate: typeof Boolean): OrderedMap<K, $NonMaybeType<V>>;
+  filter(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): OrderedMap<K, V>;
+
+  partition(
+    predicate: (value: V, key: K, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: V, key: K, iter: this) => M,
+    context?: mixed
+  ): OrderedMap<K, M>;
+
+  mapKeys<M>(
+    mapper: (key: K, value: V, iter: this) => M,
+    context?: mixed
+  ): OrderedMap<M, V>;
+
+  mapEntries<KM, VM>(
+    mapper: (entry: [K, V], index: number, iter: this) => [KM, VM],
+    context?: mixed
+  ): OrderedMap<KM, VM>;
+
+  flatMap<KM, VM>(
+    mapper: (value: V, key: K, iter: this) => Iterable<[KM, VM]>,
+    context?: mixed
+  ): OrderedMap<KM, VM>;
+
+  flatten(depth?: number): OrderedMap<any, any>;
+  flatten(shallow?: boolean): OrderedMap<any, any>;
+}
+
+declare function isSet(maybeSet: mixed): boolean %checks(maybeSet instanceof
+  Set);
+declare class Set<+T> extends SetCollection<T> {
+  static <T>(values?: Iterable<T>): Set<T>;
+
+  static of<T>(...values: T[]): Set<T>;
+  static fromKeys<T>(
+    values: Iterable<[T, mixed]> | PlainObjInput<T, mixed>
+  ): Set<T>;
+
+  static intersect<T>(sets: Iterable<Iterable<T>>): Set<T>;
+  static union<T>(sets: Iterable<Iterable<T>>): Set<T>;
+
+  static isSet: typeof isSet;
+
+  size: number;
+
+  add<U>(value: U): Set<T | U>;
+  delete(value: T): this;
+  remove(value: T): this;
+  clear(): this;
+  union<U>(...collections: Iterable<U>[]): Set<T | U>;
+  merge<U>(...collections: Iterable<U>[]): Set<T | U>;
+  concat<U>(...collections: Iterable<U>[]): Set<T | U>;
+  intersect<U>(...collections: Iterable<U>[]): Set<T & U>;
+  subtract(...collections: Iterable<mixed>[]): this;
+
+  withMutations(mutator: (mutable: this) => mixed): this;
+  asMutable(): this;
+  wasAltered(): boolean;
+  asImmutable(): this;
+
+  // Override specialized return types
+
+  filter(predicate: typeof Boolean): Set<$NonMaybeType<T>>;
+  filter(
+    predicate: (value: T, value: T, iter: this) => mixed,
+    context?: mixed
+  ): Set<T>;
+
+  partition(
+    predicate: (value: T, value: T, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: T, value: T, iter: this) => M,
+    context?: mixed
+  ): Set<M>;
+
+  flatMap<M>(
+    mapper: (value: T, value: T, iter: this) => Iterable<M>,
+    context?: mixed
+  ): Set<M>;
+
+  flatten(depth?: number): Set<any>;
+  flatten(shallow?: boolean): Set<any>;
+}
+
+// Overrides except for `isOrderedSet` are for specialized return types
+declare function isOrderedSet(
+  maybeOrderedSet: mixed
+): boolean %checks(maybeOrderedSet instanceof OrderedSet);
+declare class OrderedSet<+T> extends Set<T> {
+  static <T>(values?: Iterable<T>): OrderedSet<T>;
+
+  static of<T>(...values: T[]): OrderedSet<T>;
+  static fromKeys<T>(
+    values: Iterable<[T, mixed]> | PlainObjInput<T, mixed>
+  ): OrderedSet<T>;
+
+  static isOrderedSet: typeof isOrderedSet;
+
+  size: number;
+
+  add<U>(value: U): OrderedSet<T | U>;
+  union<U>(...collections: Iterable<U>[]): OrderedSet<T | U>;
+  merge<U>(...collections: Iterable<U>[]): OrderedSet<T | U>;
+  concat<U>(...collections: Iterable<U>[]): OrderedSet<T | U>;
+  intersect<U>(...collections: Iterable<U>[]): OrderedSet<T & U>;
+
+  filter(predicate: typeof Boolean): OrderedSet<$NonMaybeType<T>>;
+  filter(
+    predicate: (value: T, value: T, iter: this) => mixed,
+    context?: mixed
+  ): OrderedSet<T>;
+
+  partition(
+    predicate: (value: T, value: T, iter: this) => mixed,
+    context?: mixed
+  ): [this, this];
+
+  map<M>(
+    mapper: (value: T, value: T, iter: this) => M,
+    context?: mixed
+  ): OrderedSet<M>;
+
+  flatMap<M>(
+    mapper: (value: T, value: T, iter: this) => Iterable<M>,
+    context?: mixed
+  ): OrderedSet<M>;
+
+  flatten(depth?: number): OrderedSet<any>;
+  flatten(shallow?: boolean): OrderedSet<any>;
+
+  zip<A>(a: Iterable<A>, ..._: []): OrderedSet<[T, A]>;
+  zip<A, B>(a: Iterable<A>, b: Iterable<B>, ..._: []): OrderedSet<[T, A, B]>;
+  zip<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): OrderedSet<[T, A, B, C]>;
+  zip<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): OrderedSet<[T, A, B, C, D]>;
+  zip<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): OrderedSet<[T, A, B, C, D, E]>;
+
+  zipAll<A>(a: Iterable<A>, ..._: []): OrderedSet<[T | void, A | void]>;
+  zipAll<A, B>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): OrderedSet<[T | void, A | void, B | void]>;
+  zipAll<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): OrderedSet<[T | void, A | void, B | void, C | void]>;
+  zipAll<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): OrderedSet<[T | void, A | void, B | void, C | void, D | void]>;
+  zipAll<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): OrderedSet<[T | void, A | void, B | void, C | void, D | void, E | void]>;
+
+  zipWith<A, R>(
+    zipper: (value: T, a: A) => R,
+    a: Iterable<A>,
+    ..._: []
+  ): OrderedSet<R>;
+  zipWith<A, B, R>(
+    zipper: (value: T, a: A, b: B) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): OrderedSet<R>;
+  zipWith<A, B, C, R>(
+    zipper: (value: T, a: A, b: B, c: C) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): OrderedSet<R>;
+  zipWith<A, B, C, D, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): OrderedSet<R>;
+  zipWith<A, B, C, D, E, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D, e: E) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): OrderedSet<R>;
+}
+
+declare function isStack(
+  maybeStack: mixed
+): boolean %checks(maybeStack instanceof Stack);
+declare class Stack<+T> extends IndexedCollection<T> {
+  static <T>(collection?: Iterable<T>): Stack<T>;
+
+  static isStack(maybeStack: mixed): boolean;
+  static of<T>(...values: T[]): Stack<T>;
+
+  static isStack: typeof isStack;
+
+  size: number;
+
+  peek(): T;
+  clear(): this;
+  unshift<U>(...values: U[]): Stack<T | U>;
+  unshiftAll<U>(iter: Iterable<U>): Stack<T | U>;
+  shift(): this;
+  push<U>(...values: U[]): Stack<T | U>;
+  pushAll<U>(iter: Iterable<U>): Stack<T | U>;
+  pop(): this;
+
+  withMutations(mutator: (mutable: this) => mixed): this;
+  asMutable(): this;
+  wasAltered(): boolean;
+  asImmutable(): this;
+
+  // Override specialized return types
+
+  concat<C>(...iters: Array<Iterable<C> | C>): Stack<T | C>;
+
+  filter(predicate: typeof Boolean): Stack<$NonMaybeType<T>>;
+  filter(
+    predicate: (value: T, index: number, iter: this) => mixed,
+    context?: mixed
+  ): Stack<T>;
+
+  map<M>(
+    mapper: (value: T, index: number, iter: this) => M,
+    context?: mixed
+  ): Stack<M>;
+
+  flatMap<M>(
+    mapper: (value: T, index: number, iter: this) => Iterable<M>,
+    context?: mixed
+  ): Stack<M>;
+
+  flatten(depth?: number): Stack<any>;
+  flatten(shallow?: boolean): Stack<any>;
+
+  zip<A>(a: Iterable<A>, ..._: []): Stack<[T, A]>;
+  zip<A, B>(a: Iterable<A>, b: Iterable<B>, ..._: []): Stack<[T, A, B]>;
+  zip<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): Stack<[T, A, B, C]>;
+  zip<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): Stack<[T, A, B, C, D]>;
+  zip<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): Stack<[T, A, B, C, D, E]>;
+
+  zipAll<A>(a: Iterable<A>, ..._: []): Stack<[T | void, A | void]>;
+  zipAll<A, B>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): Stack<[T | void, A | void, B | void]>;
+  zipAll<A, B, C>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): Stack<[T | void, A | void, B | void, C | void]>;
+  zipAll<A, B, C, D>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): Stack<[T | void, A | void, B | void, C | void, D | void]>;
+  zipAll<A, B, C, D, E>(
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): Stack<[T | void, A | void, B | void, C | void, D | void, E | void]>;
+
+  zipWith<A, R>(
+    zipper: (value: T, a: A) => R,
+    a: Iterable<A>,
+    ..._: []
+  ): Stack<R>;
+  zipWith<A, B, R>(
+    zipper: (value: T, a: A, b: B) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    ..._: []
+  ): Stack<R>;
+  zipWith<A, B, C, R>(
+    zipper: (value: T, a: A, b: B, c: C) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    ..._: []
+  ): Stack<R>;
+  zipWith<A, B, C, D, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    ..._: []
+  ): Stack<R>;
+  zipWith<A, B, C, D, E, R>(
+    zipper: (value: T, a: A, b: B, c: C, d: D, e: E) => R,
+    a: Iterable<A>,
+    b: Iterable<B>,
+    c: Iterable<C>,
+    d: Iterable<D>,
+    e: Iterable<E>,
+    ..._: []
+  ): Stack<R>;
+}
+
+declare function Range(
+  start?: number,
+  end?: number,
+  step?: number
+): IndexedSeq<number>;
+declare function Repeat<T>(value: T, times?: number): IndexedSeq<T>;
+
+// The type of a Record factory function.
+type RecordFactory<Values: Object> = Class<RecordInstance<Values>>;
+
+// The type of runtime Record instances.
+type RecordOf<Values: Object> = RecordInstance<Values> & $ReadOnly<Values>;
+
+// The values of a Record instance.
+type _RecordValues<T, R: RecordInstance<T> | T> = R;
+type RecordValues<R> = _RecordValues<*, R>;
+
+declare function isRecord(
+  maybeRecord: any
+): boolean %checks(maybeRecord instanceof RecordInstance);
+declare class Record {
+  static <Values: Object>(spec: Values, name?: string): typeof RecordInstance;
+  constructor<Values: Object>(
+    spec: Values,
+    name?: string
+  ): typeof RecordInstance;
+
+  static isRecord: typeof isRecord;
+
+  static getDescriptiveName(record: RecordInstance<any>): string;
+}
+
+declare class RecordInstance<T: Object = Object> {
+  static (values?: Iterable<[$Keys<T>, $ValOf<T>]> | $Shape<T>): RecordOf<T>;
+  // Note: a constructor can only create an instance of RecordInstance<T>,
+  // it's encouraged to not use `new` when creating Records.
+  constructor(values?: Iterable<[$Keys<T>, $ValOf<T>]> | $Shape<T>): void;
+
+  size: number;
+
+  has(key: string): boolean;
+
+  get<K: $Keys<T>>(key: K, ..._: []): $ElementType<T, K>;
+  get<K: $Keys<T>, NSV>(key: K, notSetValue: NSV): $ElementType<T, K> | NSV;
+
+  hasIn(keyPath: Iterable<mixed>): boolean;
+
+  getIn(keyPath: [], notSetValue?: mixed): this & $ReadOnly<T>;
+  getIn<K: $Keys<T>>(keyPath: [K], notSetValue?: mixed): $ElementType<T, K>;
+  getIn<NSV, K: $Keys<T>, K2: $KeyOf<$ValOf<T, K>>>(
+    keyPath: [K, K2],
+    notSetValue: NSV
+  ): $ValOf<$ValOf<T, K>, K2> | NSV;
+  getIn<
+    NSV,
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>
+  >(
+    keyPath: [K, K2, K3],
+    notSetValue: NSV
+  ): $ValOf<$ValOf<$ValOf<T, K>, K2>, K3> | NSV;
+  getIn<
+    NSV,
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>
+  >(
+    keyPath: [K, K2, K3, K4],
+    notSetValue: NSV
+  ): $ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4> | NSV;
+  getIn<
+    NSV,
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>>
+  >(
+    keyPath: [K, K2, K3, K4, K5],
+    notSetValue: NSV
+  ): $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>, K5> | NSV;
+
+  equals(other: any): boolean;
+  hashCode(): number;
+
+  set<K: $Keys<T>>(key: K, value: $ElementType<T, K>): this & $ReadOnly<T>;
+  update<K: $Keys<T>>(
+    key: K,
+    updater: (value: $ElementType<T, K>) => $ElementType<T, K>
+  ): this & $ReadOnly<T>;
+  merge(
+    ...collections: Array<Iterable<[$Keys<T>, $ValOf<T>]> | $Shape<T>>
+  ): this & $ReadOnly<T>;
+  mergeDeep(
+    ...collections: Array<Iterable<[$Keys<T>, $ValOf<T>]> | $Shape<T>>
+  ): this & $ReadOnly<T>;
+
+  mergeWith(
+    merger: (oldVal: $ValOf<T>, newVal: $ValOf<T>, key: $Keys<T>) => $ValOf<T>,
+    ...collections: Array<Iterable<[$Keys<T>, $ValOf<T>]> | $Shape<T>>
+  ): this & $ReadOnly<T>;
+  mergeDeepWith(
+    merger: (oldVal: any, newVal: any, key: any) => any,
+    ...collections: Array<Iterable<[$Keys<T>, $ValOf<T>]> | $Shape<T>>
+  ): this & $ReadOnly<T>;
+
+  delete<K: $Keys<T>>(key: K): this & $ReadOnly<T>;
+  remove<K: $Keys<T>>(key: K): this & $ReadOnly<T>;
+  clear(): this & $ReadOnly<T>;
+
+  setIn<S>(keyPath: [], value: S): S;
+  setIn<K: $Keys<T>, S: $ValOf<T, K>>(
+    keyPath: [K],
+    value: S
+  ): this & $ReadOnly<T>;
+  setIn<K: $Keys<T>, K2: $KeyOf<$ValOf<T, K>>, S: $ValOf<$ValOf<T, K>, K2>>(
+    keyPath: [K, K2],
+    value: S
+  ): this & $ReadOnly<T>;
+  setIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    S: $ValOf<$ValOf<$ValOf<T, K>, K2>, K3>
+  >(
+    keyPath: [K, K2, K3],
+    value: S
+  ): this & $ReadOnly<T>;
+  setIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>,
+    S: $ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>
+  >(
+    keyPath: [K, K2, K3, K4],
+    value: S
+  ): this & $ReadOnly<T>;
+  setIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>>,
+    S: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>, K5>
+  >(
+    keyPath: [K, K2, K3, K4, K5],
+    value: S
+  ): this & $ReadOnly<T>;
+
+  deleteIn(keyPath: []): void;
+  deleteIn<K: $Keys<T>>(keyPath: [K]): this & $ReadOnly<T>;
+  deleteIn<K: $Keys<T>, K2: $KeyOf<$ValOf<T, K>>>(
+    keyPath: [K, K2]
+  ): this & $ReadOnly<T>;
+  deleteIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>
+  >(
+    keyPath: [K, K2, K3]
+  ): this & $ReadOnly<T>;
+  deleteIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>
+  >(
+    keyPath: [K, K2, K3, K4]
+  ): this & $ReadOnly<T>;
+  deleteIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>>
+  >(
+    keyPath: [K, K2, K3, K4, K5]
+  ): this & $ReadOnly<T>;
+
+  removeIn(keyPath: []): void;
+  removeIn<K: $Keys<T>>(keyPath: [K]): this & $ReadOnly<T>;
+  removeIn<K: $Keys<T>, K2: $KeyOf<$ValOf<T, K>>>(
+    keyPath: [K, K2]
+  ): this & $ReadOnly<T>;
+  removeIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>
+  >(
+    keyPath: [K, K2, K3]
+  ): this & $ReadOnly<T>;
+  removeIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>
+  >(
+    keyPath: [K, K2, K3, K4]
+  ): this & $ReadOnly<T>;
+  removeIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>>
+  >(
+    keyPath: [K, K2, K3, K4, K5]
+  ): this & $ReadOnly<T>;
+
+  updateIn<U>(
+    keyPath: [],
+    notSetValue: mixed,
+    updater: (value: this & T) => U
+  ): U;
+  updateIn<U>(keyPath: [], updater: (value: this & T) => U): U;
+  updateIn<NSV, K: $Keys<T>, S: $ValOf<T, K>>(
+    keyPath: [K],
+    notSetValue: NSV,
+    updater: (value: $ValOf<T, K>) => S
+  ): this & $ReadOnly<T>;
+  updateIn<K: $Keys<T>, S: $ValOf<T, K>>(
+    keyPath: [K],
+    updater: (value: $ValOf<T, K>) => S
+  ): this & $ReadOnly<T>;
+  updateIn<
+    NSV,
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    S: $ValOf<$ValOf<T, K>, K2>
+  >(
+    keyPath: [K, K2],
+    notSetValue: NSV,
+    updater: (value: $ValOf<$ValOf<T, K>, K2> | NSV) => S
+  ): this & $ReadOnly<T>;
+  updateIn<K: $Keys<T>, K2: $KeyOf<$ValOf<T, K>>, S: $ValOf<$ValOf<T, K>, K2>>(
+    keyPath: [K, K2],
+    updater: (value: $ValOf<$ValOf<T, K>, K2>) => S
+  ): this & $ReadOnly<T>;
+  updateIn<
+    NSV,
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    S: $ValOf<$ValOf<$ValOf<T, K>, K2>, K3>
+  >(
+    keyPath: [K, K2, K3],
+    notSetValue: NSV,
+    updater: (value: $ValOf<$ValOf<$ValOf<T, K>, K2>, K3> | NSV) => S
+  ): this & $ReadOnly<T>;
+  updateIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    S: $ValOf<$ValOf<$ValOf<T, K>, K2>, K3>
+  >(
+    keyPath: [K, K2, K3],
+    updater: (value: $ValOf<$ValOf<$ValOf<T, K>, K2>, K3>) => S
+  ): this & $ReadOnly<T>;
+  updateIn<
+    NSV,
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>,
+    S: $ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>
+  >(
+    keyPath: [K, K2, K3, K4],
+    notSetValue: NSV,
+    updater: (
+      value: $ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4> | NSV
+    ) => S
+  ): this & $ReadOnly<T>;
+  updateIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>,
+    S: $ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>
+  >(
+    keyPath: [K, K2, K3, K4],
+    updater: (value: $ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>) => S
+  ): this & $ReadOnly<T>;
+  updateIn<
+    NSV,
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>>,
+    S: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>, K5>
+  >(
+    keyPath: [K, K2, K3, K4, K5],
+    notSetValue: NSV,
+    updater: (
+      value: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>, K5> | NSV
+    ) => S
+  ): this & $ReadOnly<T>;
+  updateIn<
+    K: $Keys<T>,
+    K2: $KeyOf<$ValOf<T, K>>,
+    K3: $KeyOf<$ValOf<$ValOf<T, K>, K2>>,
+    K4: $KeyOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>>,
+    K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>>,
+    S: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>, K5>
+  >(
+    keyPath: [K, K2, K3, K4, K5],
+    updater: (
+      value: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<T, K>, K2>, K3>, K4>, K5>
+    ) => S
+  ): this & $ReadOnly<T>;
+
+  mergeIn(
+    keyPath: Iterable<mixed>,
+    ...collections: Array<any>
+  ): this & $ReadOnly<T>;
+  mergeDeepIn(
+    keyPath: Iterable<mixed>,
+    ...collections: Array<any>
+  ): this & $ReadOnly<T>;
+
+  toSeq(): KeyedSeq<$Keys<T>, any>;
+
+  toJS(): { [key: $Keys<T>]: mixed };
+  toJSON(): T;
+  toObject(): T;
+
+  withMutations(mutator: (mutable: this & T) => mixed): this & $ReadOnly<T>;
+  asMutable(): this & $ReadOnly<T>;
+  wasAltered(): boolean;
+  asImmutable(): this & $ReadOnly<T>;
+
+  @@iterator(): Iterator<[$Keys<T>, $ValOf<T>]>;
+}
+
+declare function fromJS(
+  jsValue: mixed,
+  reviver?: (
+    key: string | number,
+    sequence: KeyedCollection<string, mixed> | IndexedCollection<mixed>,
+    path?: Array<string | number>
+  ) => mixed
+): Collection<mixed, mixed>;
+
+declare function is(first: mixed, second: mixed): boolean;
+declare function hash(value: mixed): number;
+
+declare function get<C: Object, K: $Keys<C>>(
+  collection: C,
+  key: K,
+  notSetValue: mixed
+): $ValOf<C, K>;
+declare function get<C, K: $KeyOf<C>, NSV>(
+  collection: C,
+  key: K,
+  notSetValue: NSV
+): $ValOf<C, K> | NSV;
+
+declare function has(collection: Object, key: mixed): boolean;
+declare function remove<C>(collection: C, key: $KeyOf<C>): C;
+declare function set<C, K: $KeyOf<C>, V: $ValOf<C, K>>(
+  collection: C,
+  key: K,
+  value: V
+): C;
+declare function update<C, K: $KeyOf<C>, V: $ValOf<C, K>, NSV>(
+  collection: C,
+  key: K,
+  notSetValue: NSV,
+  updater: ($ValOf<C, K> | NSV) => V
+): C;
+declare function update<C, K: $KeyOf<C>, V: $ValOf<C, K>>(
+  collection: C,
+  key: K,
+  updater: ($ValOf<C, K>) => V
+): C;
+
+declare function getIn<C>(collection: C, keyPath: [], notSetValue?: mixed): C;
+declare function getIn<C, K: $KeyOf<C>, NSV>(
+  collection: C,
+  keyPath: [K],
+  notSetValue: NSV
+): $ValOf<C, K> | NSV;
+declare function getIn<C, K: $KeyOf<C>, K2: $KeyOf<$ValOf<C, K>>, NSV>(
+  collection: C,
+  keyPath: [K, K2],
+  notSetValue: NSV
+): $ValOf<$ValOf<C, K>, K2> | NSV;
+declare function getIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  NSV
+>(
+  collection: C,
+  keyPath: [K, K2, K3],
+  notSetValue: NSV
+): $ValOf<$ValOf<$ValOf<C, K>, K2>, K3> | NSV;
+declare function getIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>,
+  NSV
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4],
+  notSetValue: NSV
+): $ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4> | NSV;
+declare function getIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>,
+  K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>>,
+  NSV
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4, K5],
+  notSetValue: NSV
+): $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>, K5> | NSV;
+
+declare function hasIn(collection: Object, keyPath: Iterable<mixed>): boolean;
+
+declare function removeIn<C>(collection: C, keyPath: []): void;
+declare function removeIn<C, K: $KeyOf<C>>(collection: C, keyPath: [K]): C;
+declare function removeIn<C, K: $KeyOf<C>, K2: $KeyOf<$ValOf<C, K>>>(
+  collection: C,
+  keyPath: [K, K2]
+): C;
+declare function removeIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>
+>(
+  collection: C,
+  keyPath: [K, K2, K3]
+): C;
+declare function removeIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4]
+): C;
+declare function removeIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>,
+  K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>>
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4, K5]
+): C;
+
+declare function setIn<S>(collection: Object, keyPath: [], value: S): S;
+declare function setIn<C, K: $KeyOf<C>, S: $ValOf<C, K>>(
+  collection: C,
+  keyPath: [K],
+  value: S
+): C;
+declare function setIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  S: $ValOf<$ValOf<C, K>, K2>
+>(
+  collection: C,
+  keyPath: [K, K2],
+  value: S
+): C;
+declare function setIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  S: $ValOf<$ValOf<$ValOf<C, K>, K2>, K3>
+>(
+  collection: C,
+  keyPath: [K, K2, K3],
+  value: S
+): C;
+declare function setIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>,
+  S: $ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4],
+  value: S
+): C;
+declare function setIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>,
+  K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>>,
+  S: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>, K5>
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4, K5],
+  value: S
+): C;
+
+declare function updateIn<C, S>(
+  collection: C,
+  keyPath: [],
+  notSetValue: mixed,
+  updater: (value: C) => S
+): S;
+declare function updateIn<C, S>(
+  collection: C,
+  keyPath: [],
+  updater: (value: C) => S
+): S;
+declare function updateIn<C, K: $KeyOf<C>, S: $ValOf<C, K>, NSV>(
+  collection: C,
+  keyPath: [K],
+  notSetValue: NSV,
+  updater: (value: $ValOf<C, K> | NSV) => S
+): C;
+declare function updateIn<C, K: $KeyOf<C>, S: $ValOf<C, K>>(
+  collection: C,
+  keyPath: [K],
+  updater: (value: $ValOf<C, K>) => S
+): C;
+declare function updateIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  S: $ValOf<$ValOf<C, K>, K2>,
+  NSV
+>(
+  collection: C,
+  keyPath: [K, K2],
+  notSetValue: NSV,
+  updater: (value: $ValOf<$ValOf<C, K>, K2> | NSV) => S
+): C;
+declare function updateIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  S: $ValOf<$ValOf<C, K>, K2>
+>(
+  collection: C,
+  keyPath: [K, K2],
+  updater: (value: $ValOf<$ValOf<C, K>, K2>) => S
+): C;
+declare function updateIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  S: $ValOf<$ValOf<$ValOf<C, K>, K2>, K3>,
+  NSV
+>(
+  collection: C,
+  keyPath: [K, K2, K3],
+  notSetValue: NSV,
+  updater: (value: $ValOf<$ValOf<$ValOf<C, K>, K2>, K3> | NSV) => S
+): C;
+declare function updateIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  S: $ValOf<$ValOf<$ValOf<C, K>, K2>, K3>
+>(
+  collection: C,
+  keyPath: [K, K2, K3],
+  updater: (value: $ValOf<$ValOf<$ValOf<C, K>, K2>, K3>) => S
+): C;
+declare function updateIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>,
+  S: $ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>,
+  NSV
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4],
+  notSetValue: NSV,
+  updater: (value: $ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4> | NSV) => S
+): C;
+declare function updateIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>,
+  S: $ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4],
+  updater: (value: $ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>) => S
+): C;
+declare function updateIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>,
+  K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>>,
+  S: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>, K5>,
+  NSV
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4, K5],
+  notSetValue: NSV,
+  updater: (
+    value: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>, K5> | NSV
+  ) => S
+): C;
+declare function updateIn<
+  C,
+  K: $KeyOf<C>,
+  K2: $KeyOf<$ValOf<C, K>>,
+  K3: $KeyOf<$ValOf<$ValOf<C, K>, K2>>,
+  K4: $KeyOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>>,
+  K5: $KeyOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>>,
+  S: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>, K5>
+>(
+  collection: C,
+  keyPath: [K, K2, K3, K4, K5],
+  updater: (
+    value: $ValOf<$ValOf<$ValOf<$ValOf<$ValOf<C, K>, K2>, K3>, K4>, K5>
+  ) => S
+): C;
+
+declare function merge<C>(
+  collection: C,
+  ...collections: Array<
+    | $IterableOf<C>
+    | $Shape<RecordValues<C>>
+    | PlainObjInput<$KeyOf<C>, $ValOf<C>>
+  >
+): C;
+declare function mergeWith<C>(
+  merger: (oldVal: $ValOf<C>, newVal: $ValOf<C>, key: $KeyOf<C>) => $ValOf<C>,
+  collection: C,
+  ...collections: Array<
+    | $IterableOf<C>
+    | $Shape<RecordValues<C>>
+    | PlainObjInput<$KeyOf<C>, $ValOf<C>>
+  >
+): C;
+declare function mergeDeep<C>(
+  collection: C,
+  ...collections: Array<
+    | $IterableOf<C>
+    | $Shape<RecordValues<C>>
+    | PlainObjInput<$KeyOf<C>, $ValOf<C>>
+  >
+): C;
+declare function mergeDeepWith<C>(
+  merger: (oldVal: any, newVal: any, key: any) => mixed,
+  collection: C,
+  ...collections: Array<
+    | $IterableOf<C>
+    | $Shape<RecordValues<C>>
+    | PlainObjInput<$KeyOf<C>, $ValOf<C>>
+  >
+): C;
+
+export {
+  Collection,
+  Seq,
+  List,
+  Map,
+  OrderedMap,
+  OrderedSet,
+  Range,
+  Repeat,
+  Record,
+  Set,
+  Stack,
+  fromJS,
+  is,
+  hash,
+  isImmutable,
+  isCollection,
+  isKeyed,
+  isIndexed,
+  isAssociative,
+  isOrdered,
+  isRecord,
+  isValueObject,
+  get,
+  has,
+  remove,
+  set,
+  update,
+  getIn,
+  hasIn,
+  removeIn,
+  setIn,
+  updateIn,
+  merge,
+  mergeWith,
+  mergeDeep,
+  mergeDeepWith,
+};
+
+export default {
+  Collection,
+  Seq,
+
+  List,
+  Map,
+  OrderedMap,
+  OrderedSet,
+  PairSorting,
+  Range,
+  Repeat,
+  Record,
+  Set,
+  Stack,
+
+  fromJS,
+  is,
+  hash,
+
+  isImmutable,
+  isCollection,
+  isKeyed,
+  isIndexed,
+  isAssociative,
+  isOrdered,
+  isRecord,
+  isValueObject,
+
+  get,
+  has,
+  remove,
+  set,
+  update,
+  getIn,
+  hasIn,
+  removeIn,
+  setIn,
+  updateIn,
+  merge,
+  mergeWith,
+  mergeDeep,
+  mergeDeepWith,
+};
+
+export type {
+  Comparator,
+  KeyedCollection,
+  IndexedCollection,
+  SetCollection,
+  KeyedSeq,
+  IndexedSeq,
+  SetSeq,
+  RecordFactory,
+  RecordOf,
+  RecordInstance,
+  ValueObject,
+  $KeyOf,
+  $ValOf,
+};
