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Implement type narrowing for Array.prototype.includes #58988

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920eeb8
Relax search element in Array.prototype.includes
jrandolf Jun 24, 2024
5752b7a
Relax search element in Array.prototype.includes
jrandolf Jun 24, 2024
0c1317b
chore: tests
jrandolf Jun 24, 2024
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4 changes: 2 additions & 2 deletions src/lib/es2016.array.include.d.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ interface Array<T> {
* @param searchElement The element to search for.
* @param fromIndex The position in this array at which to begin searching for searchElement.
*/
includes(searchElement: T, fromIndex?: number): boolean;
includes<U>(searchElement: U, fromIndex?: number): searchElement is T extends U ? T : never;
}

interface ReadonlyArray<T> {
Expand All @@ -13,7 +13,7 @@ interface ReadonlyArray<T> {
* @param searchElement The element to search for.
* @param fromIndex The position in this array at which to begin searching for searchElement.
*/
includes(searchElement: T, fromIndex?: number): boolean;
includes<U>(searchElement: U, fromIndex?: number): searchElement is T extends U ? T : never;
}

interface Int8Array {
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32 changes: 32 additions & 0 deletions tests/baselines/reference/arrayIncludes.errors.txt
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@@ -0,0 +1,32 @@
arrayIncludes.ts(10,12): error TS2339: Property 'length' does not exist on type 'never'.
arrayIncludes.ts(21,12): error TS2339: Property 'length' does not exist on type 'never'.


==== arrayIncludes.ts (2 errors) ====
const array1 = ['foo', 'bar'] as const;

const value1: string = 'baz';
if (array1.includes(value1)) {
value1.length;
}

const value2 = 'baz';
if (array1.includes(value2)) {
value2.length;
~~~~~~
!!! error TS2339: Property 'length' does not exist on type 'never'.
}

const value3 = 'bar';
if (array1.includes(value3)) {
value3.length;
}

const value4 = 'baz';
const result0 = array1.includes(value4);
if (result0) {
value4.length;
~~~~~~
!!! error TS2339: Property 'length' does not exist on type 'never'.
}

46 changes: 46 additions & 0 deletions tests/baselines/reference/arrayIncludes.js
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@@ -0,0 +1,46 @@
//// [tests/cases/compiler/arrayIncludes.ts] ////

//// [arrayIncludes.ts]
const array1 = ['foo', 'bar'] as const;

const value1: string = 'baz';
if (array1.includes(value1)) {
value1.length;
}

const value2 = 'baz';
if (array1.includes(value2)) {
value2.length;
}

const value3 = 'bar';
if (array1.includes(value3)) {
value3.length;
}

const value4 = 'baz';
const result0 = array1.includes(value4);
if (result0) {
value4.length;
}


//// [arrayIncludes.js]
const array1 = ['foo', 'bar'];
const value1 = 'baz';
if (array1.includes(value1)) {
value1.length;
}
const value2 = 'baz';
if (array1.includes(value2)) {
value2.length;
}
const value3 = 'bar';
if (array1.includes(value3)) {
value3.length;
}
const value4 = 'baz';
const result0 = array1.includes(value4);
if (result0) {
value4.length;
}
67 changes: 67 additions & 0 deletions tests/baselines/reference/arrayIncludes.symbols
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@@ -0,0 +1,67 @@
//// [tests/cases/compiler/arrayIncludes.ts] ////

=== arrayIncludes.ts ===
const array1 = ['foo', 'bar'] as const;
>array1 : Symbol(array1, Decl(arrayIncludes.ts, 0, 5))
>const : Symbol(const)

const value1: string = 'baz';
>value1 : Symbol(value1, Decl(arrayIncludes.ts, 2, 5))

if (array1.includes(value1)) {
>array1.includes : Symbol(ReadonlyArray.includes, Decl(lib.es2016.array.include.d.ts, --, --))
>array1 : Symbol(array1, Decl(arrayIncludes.ts, 0, 5))
>includes : Symbol(ReadonlyArray.includes, Decl(lib.es2016.array.include.d.ts, --, --))
>value1 : Symbol(value1, Decl(arrayIncludes.ts, 2, 5))

value1.length;
>value1.length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
>value1 : Symbol(value1, Decl(arrayIncludes.ts, 2, 5))
>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
}

const value2 = 'baz';
>value2 : Symbol(value2, Decl(arrayIncludes.ts, 7, 5))

if (array1.includes(value2)) {
>array1.includes : Symbol(ReadonlyArray.includes, Decl(lib.es2016.array.include.d.ts, --, --))
>array1 : Symbol(array1, Decl(arrayIncludes.ts, 0, 5))
>includes : Symbol(ReadonlyArray.includes, Decl(lib.es2016.array.include.d.ts, --, --))
>value2 : Symbol(value2, Decl(arrayIncludes.ts, 7, 5))

value2.length;
>value2 : Symbol(value2, Decl(arrayIncludes.ts, 7, 5))
}

const value3 = 'bar';
>value3 : Symbol(value3, Decl(arrayIncludes.ts, 12, 5))

if (array1.includes(value3)) {
>array1.includes : Symbol(ReadonlyArray.includes, Decl(lib.es2016.array.include.d.ts, --, --))
>array1 : Symbol(array1, Decl(arrayIncludes.ts, 0, 5))
>includes : Symbol(ReadonlyArray.includes, Decl(lib.es2016.array.include.d.ts, --, --))
>value3 : Symbol(value3, Decl(arrayIncludes.ts, 12, 5))

value3.length;
>value3.length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
>value3 : Symbol(value3, Decl(arrayIncludes.ts, 12, 5))
>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
}

const value4 = 'baz';
>value4 : Symbol(value4, Decl(arrayIncludes.ts, 17, 5))

const result0 = array1.includes(value4);
>result0 : Symbol(result0, Decl(arrayIncludes.ts, 18, 5))
>array1.includes : Symbol(ReadonlyArray.includes, Decl(lib.es2016.array.include.d.ts, --, --))
>array1 : Symbol(array1, Decl(arrayIncludes.ts, 0, 5))
>includes : Symbol(ReadonlyArray.includes, Decl(lib.es2016.array.include.d.ts, --, --))
>value4 : Symbol(value4, Decl(arrayIncludes.ts, 17, 5))

if (result0) {
>result0 : Symbol(result0, Decl(arrayIncludes.ts, 18, 5))

value4.length;
>value4 : Symbol(value4, Decl(arrayIncludes.ts, 17, 5))
}

129 changes: 129 additions & 0 deletions tests/baselines/reference/arrayIncludes.types
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@@ -0,0 +1,129 @@
//// [tests/cases/compiler/arrayIncludes.ts] ////

=== arrayIncludes.ts ===
const array1 = ['foo', 'bar'] as const;
>array1 : readonly ["foo", "bar"]
> : ^^^^^^^^^^^^^^^^^^^^^^^
>['foo', 'bar'] as const : readonly ["foo", "bar"]
> : ^^^^^^^^^^^^^^^^^^^^^^^
>['foo', 'bar'] : readonly ["foo", "bar"]
> : ^^^^^^^^^^^^^^^^^^^^^^^
>'foo' : "foo"
> : ^^^^^
>'bar' : "bar"
> : ^^^^^

const value1: string = 'baz';
>value1 : string
> : ^^^^^^
>'baz' : "baz"
> : ^^^^^

if (array1.includes(value1)) {
>array1.includes(value1) : boolean
> : ^^^^^^^
>array1.includes : <U>(searchElement: U, fromIndex?: number) => searchElement is ("foo" extends infer T ? T extends "foo" ? T extends U ? U & ("foo" | "bar") : never : never : never) | ("bar" extends infer T_1 ? T_1 extends "bar" ? T_1 extends U ? U & ("foo" | "bar") : never : never : never)
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>array1 : readonly ["foo", "bar"]
> : ^^^^^^^^^^^^^^^^^^^^^^^
>includes : <U>(searchElement: U, fromIndex?: number) => searchElement is ("foo" extends infer T ? T extends "foo" ? T extends U ? U & ("foo" | "bar") : never : never : never) | ("bar" extends infer T_1 ? T_1 extends "bar" ? T_1 extends U ? U & ("foo" | "bar") : never : never : never)
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>value1 : string
> : ^^^^^^

value1.length;
>value1.length : number
> : ^^^^^^
>value1 : "foo" | "bar"
> : ^^^^^^^^^^^^^
>length : number
> : ^^^^^^
}

const value2 = 'baz';
>value2 : "baz"
> : ^^^^^
>'baz' : "baz"
> : ^^^^^

if (array1.includes(value2)) {
>array1.includes(value2) : boolean
> : ^^^^^^^
>array1.includes : <U>(searchElement: U, fromIndex?: number) => searchElement is ("foo" extends infer T ? T extends "foo" ? T extends U ? U & ("foo" | "bar") : never : never : never) | ("bar" extends infer T_1 ? T_1 extends "bar" ? T_1 extends U ? U & ("foo" | "bar") : never : never : never)
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>array1 : readonly ["foo", "bar"]
> : ^^^^^^^^^^^^^^^^^^^^^^^
>includes : <U>(searchElement: U, fromIndex?: number) => searchElement is ("foo" extends infer T ? T extends "foo" ? T extends U ? U & ("foo" | "bar") : never : never : never) | ("bar" extends infer T_1 ? T_1 extends "bar" ? T_1 extends U ? U & ("foo" | "bar") : never : never : never)
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>value2 : "baz"
> : ^^^^^

value2.length;
>value2.length : any
> : ^^^
>value2 : never
> : ^^^^^
>length : any
> : ^^^
}

const value3 = 'bar';
>value3 : "bar"
> : ^^^^^
>'bar' : "bar"
> : ^^^^^

if (array1.includes(value3)) {
>array1.includes(value3) : boolean
> : ^^^^^^^
>array1.includes : <U>(searchElement: U, fromIndex?: number) => searchElement is ("foo" extends infer T ? T extends "foo" ? T extends U ? U & ("foo" | "bar") : never : never : never) | ("bar" extends infer T_1 ? T_1 extends "bar" ? T_1 extends U ? U & ("foo" | "bar") : never : never : never)
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>array1 : readonly ["foo", "bar"]
> : ^^^^^^^^^^^^^^^^^^^^^^^
>includes : <U>(searchElement: U, fromIndex?: number) => searchElement is ("foo" extends infer T ? T extends "foo" ? T extends U ? U & ("foo" | "bar") : never : never : never) | ("bar" extends infer T_1 ? T_1 extends "bar" ? T_1 extends U ? U & ("foo" | "bar") : never : never : never)
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>value3 : "bar"
> : ^^^^^

value3.length;
>value3.length : number
> : ^^^^^^
>value3 : "bar"
> : ^^^^^
>length : number
> : ^^^^^^
}

const value4 = 'baz';
>value4 : "baz"
> : ^^^^^
>'baz' : "baz"
> : ^^^^^

const result0 = array1.includes(value4);
>result0 : boolean
> : ^^^^^^^
>array1.includes(value4) : boolean
> : ^^^^^^^
>array1.includes : <U>(searchElement: U, fromIndex?: number) => searchElement is ("foo" extends infer T ? T extends "foo" ? T extends U ? U & ("foo" | "bar") : never : never : never) | ("bar" extends infer T_1 ? T_1 extends "bar" ? T_1 extends U ? U & ("foo" | "bar") : never : never : never)
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>array1 : readonly ["foo", "bar"]
> : ^^^^^^^^^^^^^^^^^^^^^^^
>includes : <U>(searchElement: U, fromIndex?: number) => searchElement is ("foo" extends infer T ? T extends "foo" ? T extends U ? U & ("foo" | "bar") : never : never : never) | ("bar" extends infer T_1 ? T_1 extends "bar" ? T_1 extends U ? U & ("foo" | "bar") : never : never : never)
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>value4 : "baz"
> : ^^^^^

if (result0) {
>result0 : boolean
> : ^^^^^^^

value4.length;
>value4.length : any
> : ^^^
>value4 : never
> : ^^^^^
>length : any
> : ^^^
}

8 changes: 4 additions & 4 deletions tests/baselines/reference/discriminantNarrowingCouldBeCircular.types
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Expand Up @@ -120,12 +120,12 @@ function getImplicitAriaRole(element: SomeRecord) {
> : ^^^^^^^
>parents.includes(parent.a) : boolean
> : ^^^^^^^
>parents.includes : (searchElement: string, fromIndex?: number) => boolean
> : ^ ^^^^^^^^^^ ^^^ ^^^^^
>parents.includes : <U>(searchElement: U, fromIndex?: number) => searchElement is string extends infer T ? T extends string ? T extends U ? U & string : never : never : never
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>parents : string[]
> : ^^^^^^^^
>includes : (searchElement: string, fromIndex?: number) => boolean
> : ^ ^^^^^^^^^^ ^^^ ^^^^^
>includes : <U>(searchElement: U, fromIndex?: number) => searchElement is string extends infer T ? T extends string ? T extends U ? U & string : never : never : never
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>parent.a : string
> : ^^^^^^
>parent : SomeRecord
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2 changes: 1 addition & 1 deletion tests/baselines/reference/excessiveStackDepthFlatArray.types
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@@ -1,7 +1,7 @@
//// [tests/cases/compiler/excessiveStackDepthFlatArray.ts] ////

=== Performance Stats ===
Instantiation count: 1,000
Instantiation count: 2,500

=== index.tsx ===
interface MiddlewareArray<T> extends Array<T> {}
Expand Down
8 changes: 4 additions & 4 deletions tests/baselines/reference/keyofAndIndexedAccess2.types
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Expand Up @@ -649,12 +649,12 @@ export function getEntity<E extends Entity>(id: IdOf<E>, state: EntityState<E>):
> : ^^^^^^^
>ids.includes(id) : boolean
> : ^^^^^^^
>ids.includes : (searchElement: IdOf<E>, fromIndex?: number) => boolean
> : ^ ^^^^^^^^^^^ ^^^ ^^^^^
>ids.includes : <U>(searchElement: U, fromIndex?: number) => searchElement is IdOf<E> extends infer T ? T extends IdOf<E> ? T extends U ? IdOf<E> : never : never : never
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>ids : IdOf<E>[]
> : ^^^^^^^^^
>includes : (searchElement: IdOf<E>, fromIndex?: number) => boolean
> : ^ ^^^^^^^^^^^ ^^^ ^^^^^
>includes : <U>(searchElement: U, fromIndex?: number) => searchElement is IdOf<E> extends infer T ? T extends IdOf<E> ? T extends U ? IdOf<E> : never : never : never
> : ^ ^^ ^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>id : IdOf<E>
> : ^^^^^^^

Expand Down
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