fix the tacit use of flatten (#1724)

.changeset/eight-taxis-remain.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Chunk: fix the tacit use of flatten

.changeset/sweet-rings-play.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+ReadonlyArray: fix the tacit use of flatten

docs/modules/Chunk.ts.md

@@ -98,6 +98,7 @@ Added in v2.0.0
  - [unsafeLast](#unsafelast)
 - [utils](#utils)
  - [Chunk (namespace)](#chunk-namespace)
+ - [Flatten (type alias)](#flatten-type-alias)
  - [Infer (type alias)](#infer-type-alias)
  - [With (type alias)](#with-type-alias)
  - [With2 (type alias)](#with2-type-alias)
@@ -1047,10 +1048,7 @@ Flattens a chunk of chunks into a single chunk by concatenating all chunks.
 **Signature**
 
 ```ts
-export declare const flatten: {
- <A>(self: NonEmptyChunk<NonEmptyChunk<A>>): NonEmptyChunk<A>
- <A>(self: Chunk<Chunk<A>>): Chunk<A>
-}
+export declare const flatten: <T extends Chunk<Chunk<any>>>(self: T) => Chunk.Flatten<T>
 ```
 
 Added in v2.0.0
@@ -1149,6 +1147,20 @@ Added in v2.0.0
 
 Added in v2.0.0
 
+### Flatten (type alias)
+
+**Signature**
+
+```ts
+export type Flatten<T extends Chunk<Chunk<any>>> = T extends NonEmptyChunk<NonEmptyChunk<infer A>>
+ ? NonEmptyChunk<A>
+ : T extends Chunk<Chunk<infer A>>
+ ? Chunk<A>
+ : never
+```
+
+Added in v2.0.0
+
 ### Infer (type alias)
 
 **Signature**

docs/modules/ReadonlyArray.ts.md

@@ -124,6 +124,7 @@ Added in v2.0.0
  - [unsafeGet](#unsafeget)
 - [utils](#utils)
  - [ReadonlyArray (namespace)](#readonlyarray-namespace)
+ - [Flatten (type alias)](#flatten-type-alias)
  - [Infer (type alias)](#infer-type-alias)
  - [With (type alias)](#with-type-alias)
  - [With2 (type alias)](#with2-type-alias)
@@ -1496,10 +1497,7 @@ Flattens an array of arrays into a single array by concatenating all arrays.
 **Signature**
 
 ```ts
-export declare const flatten: {
- <A>(self: readonly [readonly [A, ...A[]], ...(readonly [A, ...A[]])[]]): [A, ...A[]]
- <A>(self: readonly (readonly A[])[]): A[]
-}
+export declare const flatten: <T extends readonly (readonly any[])[]>(self: T) => ReadonlyArray.Flatten<T>
 ```
 
 Added in v2.0.0
@@ -1578,6 +1576,22 @@ Added in v2.0.0
 
 Added in v2.0.0
 
+### Flatten (type alias)
+
+**Signature**
+
+```ts
+export type Flatten<T extends ReadonlyArray<ReadonlyArray<any>>> = T extends NonEmptyReadonlyArray<
+ NonEmptyReadonlyArray<infer A>
+>
+ ? NonEmptyArray<A>
+ : T extends ReadonlyArray<ReadonlyArray<infer A>>
+ ? Array<A>
+ : never
+```
+
+Added in v2.0.0
+
 ### Infer (type alias)
 
 **Signature**

dtslint/Chunk.ts

@@ -1,4 +1,5 @@
 import * as Chunk from "effect/Chunk"
+import * as Effect from "effect/Effect"
 import { hole, pipe } from "effect/Function"
 import * as Predicate from "effect/Predicate"
 
@@ -398,3 +399,18 @@ Chunk.flatten(hole<Chunk.NonEmptyChunk<Chunk.Chunk<number>>>())
 
 // $ExpectType NonEmptyChunk<number>
 Chunk.flatten(hole<Chunk.NonEmptyChunk<Chunk.NonEmptyChunk<number>>>())
+
+declare const flattenChunk: Effect.Effect<never, never, Chunk.Chunk<Chunk.Chunk<number>>>
+declare const flattenNonEmptyChunk: Effect.Effect<never, never, Chunk.NonEmptyChunk<Chunk.NonEmptyChunk<number>>>
+
+// $ExpectType Effect<never, never, Chunk<number>>
+flattenChunk.pipe(Effect.map((_) => Chunk.flatten(_)))
+
+// $ExpectType Effect<never, never, Chunk<number>>
+flattenChunk.pipe(Effect.map(Chunk.flatten))
+
+// $ExpectType Effect<never, never, NonEmptyChunk<number>>
+flattenNonEmptyChunk.pipe(Effect.map((_) => Chunk.flatten(_)))
+
+// $ExpectType Effect<never, never, NonEmptyChunk<number>>
+flattenNonEmptyChunk.pipe(Effect.map(Chunk.flatten))

dtslint/ReadonlyArray.ts

@@ -1,3 +1,4 @@
+import * as Effect from "effect/Effect"
 import * as Equal from "effect/Equal"
 import { hole, pipe } from "effect/Function"
 import * as Option from "effect/Option"
@@ -462,6 +463,25 @@ ReadonlyArray.flatten(hole<ReadonlyArray.NonEmptyArray<Array<number>>>())
 // $ExpectType [number, ...number[]]
 ReadonlyArray.flatten(hole<ReadonlyArray.NonEmptyReadonlyArray<ReadonlyArray.NonEmptyReadonlyArray<number>>>())
 
+declare const flattenArray: Effect.Effect<never, never, ReadonlyArray<ReadonlyArray<number>>>
+declare const flattenNonEmptyArray: Effect.Effect<
+ never,
+ never,
+ ReadonlyArray.NonEmptyReadonlyArray<ReadonlyArray.NonEmptyReadonlyArray<number>>
+>
+
+// $ExpectType Effect<never, never, number[]>
+flattenArray.pipe(Effect.map((_) => ReadonlyArray.flatten(_)))
+
+// $ExpectType Effect<never, never, number[]>
+flattenArray.pipe(Effect.map(ReadonlyArray.flatten))
+
+// $ExpectType Effect<never, never, [number, ...number[]]>
+flattenNonEmptyArray.pipe(Effect.map((_) => ReadonlyArray.flatten(_)))
+
+// $ExpectType Effect<never, never, [number, ...number[]]>
+flattenNonEmptyArray.pipe(Effect.map(ReadonlyArray.flatten))
+
 // -------------------------------------------------------------------------------------
 // prependAll
 // -------------------------------------------------------------------------------------

src/Chunk.ts

@@ -720,10 +720,7 @@ export const forEach: {
  * @since 2.0.0
  * @category sequencing
  */
-export const flatten: {
- <A>(self: NonEmptyChunk<NonEmptyChunk<A>>): NonEmptyChunk<A>
- <A>(self: Chunk<Chunk<A>>): Chunk<A>
-} = flatMap(identity) as any
+export const flatten: <T extends Chunk<Chunk<any>>>(self: T) => Chunk.Flatten<T> = flatMap(identity) as any
 
 /**
  * Groups elements in chunks of up to `n` elements.
@@ -843,6 +840,13 @@ export declare namespace Chunk {
  export type With2<S extends Chunk<any>, T extends Chunk<any>, A> = S extends NonEmptyChunk<any> ? NonEmptyChunk<A>
  : T extends NonEmptyChunk<any> ? NonEmptyChunk<A>
  : Chunk<A>
+
+ /**
+ * @since 2.0.0
+ */
+ export type Flatten<T extends Chunk<Chunk<any>>> = T extends NonEmptyChunk<NonEmptyChunk<infer A>> ? NonEmptyChunk<A>
+ : T extends Chunk<Chunk<infer A>> ? Chunk<A>
+ : never
 }
 
 /**

src/ReadonlyArray.ts

@@ -1417,6 +1417,14 @@ export declare namespace ReadonlyArray {
  S extends NonEmptyReadonlyArray<any> ? NonEmptyArray<A>
  : T extends NonEmptyReadonlyArray<any> ? NonEmptyArray<A>
  : Array<A>
+
+ /**
+ * @since 2.0.0
+ */
+ export type Flatten<T extends ReadonlyArray<ReadonlyArray<any>>> = T extends
+ NonEmptyReadonlyArray<NonEmptyReadonlyArray<infer A>> ? NonEmptyArray<A>
+ : T extends ReadonlyArray<ReadonlyArray<infer A>> ? Array<A>
+ : never
 }
 
 /**
@@ -1462,10 +1470,9 @@ export const flatMap: {
  * @category sequencing
  * @since 2.0.0
  */
-export const flatten: {
- <A>(self: NonEmptyReadonlyArray<NonEmptyReadonlyArray<A>>): NonEmptyArray<A>
- <A>(self: ReadonlyArray<ReadonlyArray<A>>): Array<A>
-} = flatMap(identity) as any
+export const flatten: <T extends ReadonlyArray<ReadonlyArray<any>>>(self: T) => ReadonlyArray.Flatten<T> = flatMap(
+ identity
+) as any
 
 /**
  * @category filtering

src/internal/fiberRuntime.ts

@@ -3081,7 +3081,7 @@ export const fiberAll = <E, A>(fibers: Iterable<Fiber.Fiber<E, A>>): Fiber.Fiber
  [internalFiber.FiberTypeId]: internalFiber.fiberVariance,
  id: () => RA.fromIterable(fibers).reduce((id, fiber) => FiberId.combine(id, fiber.id()), FiberId.none),
  await: core.exit(forEachParUnbounded(fibers, (fiber) => core.flatten(fiber.await), false)),
- children: core.map(forEachParUnbounded(fibers, (fiber) => fiber.children, false), (children) => RA.flatten(children)),
+ children: core.map(forEachParUnbounded(fibers, (fiber) => fiber.children, false), RA.flatten),
  inheritAll: core.forEachSequentialDiscard(fibers, (fiber) => fiber.inheritAll),
  poll: core.map(
  core.forEachSequential(fibers, (fiber) => fiber.poll),