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jablkojablko
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Better typings for Array.concat() and .flatMap()
1 parent 20e2be1 commit 8c1e5e1

37 files changed

+108
-140
lines changed

‎src/harness/fourslash.ts

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4685,6 +4685,7 @@ namespace FourSlashInterface {
46854685
varEntry("JSON"),
46864686
interfaceEntry("ReadonlyArray"),
46874687
interfaceEntry("ConcatArray"),
4688+
typeEntry("ConcatFlatten"),
46884689
varEntry("Array"),
46894690
interfaceEntry("ArrayConstructor"),
46904691
interfaceEntry("TypedPropertyDescriptor"),

‎src/lib/es2019.array.d.ts

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -11,9 +11,9 @@ interface ReadonlyArray<T> {
1111
* thisArg is omitted, undefined is used as the this value.
1212
*/
1313
flatMap<U, This = undefined> (
14-
callback: (this: This, value: T, index: number, array: T[]) => U | ReadonlyArray<U>,
14+
callback: (this: This, value: T, index: number, array: T[]) => U,
1515
thisArg?: This
16-
): U[]
16+
): (U extends readonly (infer V)[] ? V : U)[]
1717

1818

1919
/**
@@ -125,9 +125,9 @@ interface Array<T> {
125125
* thisArg is omitted, undefined is used as the this value.
126126
*/
127127
flatMap<U, This = undefined> (
128-
callback: (this: This, value: T, index: number, array: T[]) => U | ReadonlyArray<U>,
128+
callback: (this: This, value: T, index: number, array: T[]) => U,
129129
thisArg?: This
130-
): U[]
130+
): (U extends readonly (infer V)[] ? V : U)[]
131131

132132
/**
133133
* Returns a new array with all sub-array elements concatenated into it recursively up to the

‎src/lib/es5.d.ts

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1085,7 +1085,7 @@ interface ReadonlyArray<T> {
10851085
* Combines two or more arrays.
10861086
* @param items Additional items to add to the end of array1.
10871087
*/
1088-
concat(...items: (T | ConcatArray<T>)[]): T[];
1088+
concat<U extends any[]>(...items: U): (T | ConcatFlatten<U[number]>)[];
10891089
/**
10901090
* Adds all the elements of an array separated by the specified separator string.
10911091
* @param separator A string used to separate one element of an array from the next in the resulting String. If omitted, the array elements are separated with a comma.
@@ -1181,6 +1181,7 @@ interface ConcatArray<T> {
11811181
join(separator?: string): string;
11821182
slice(start?: number, end?: number): T[];
11831183
}
1184+
type ConcatFlatten<T> = T extends ConcatArray<infer U> ? U : T;
11841185

11851186
interface Array<T> {
11861187
/**
@@ -1213,7 +1214,7 @@ interface Array<T> {
12131214
* Combines two or more arrays.
12141215
* @param items Additional items to add to the end of array1.
12151216
*/
1216-
concat(...items: (T | ConcatArray<T>)[]): T[];
1217+
concat<U extends any[]>(...items: U): (T | ConcatFlatten<U[number]>)[];
12171218
/**
12181219
* Adds all the elements of an array separated by the specified separator string.
12191220
* @param separator A string used to separate one element of an array from the next in the resulting String. If omitted, the array elements are separated with a comma.

‎tests/baselines/reference/arrayConcat2.types

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -5,17 +5,17 @@ var a: string[] = [];
55

66
a.concat("hello", 'world');
77
>a.concat("hello", 'world') : string[]
8-
>a.concat : { (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; }
8+
>a.concat : { (...items: ConcatArray<string>[]): string[]; <U extends any[]>(...items: U): (string | ConcatFlatten<U[number]>)[]; }
99
>a : string[]
10-
>concat : { (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; }
10+
>concat : { (...items: ConcatArray<string>[]): string[]; <U extends any[]>(...items: U): (string | ConcatFlatten<U[number]>)[]; }
1111
>"hello" : "hello"
1212
>'world' : "world"
1313

1414
a.concat('Hello');
1515
>a.concat('Hello') : string[]
16-
>a.concat : { (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; }
16+
>a.concat : { (...items: ConcatArray<string>[]): string[]; <U extends any[]>(...items: U): (string | ConcatFlatten<U[number]>)[]; }
1717
>a : string[]
18-
>concat : { (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; }
18+
>concat : { (...items: ConcatArray<string>[]): string[]; <U extends any[]>(...items: U): (string | ConcatFlatten<U[number]>)[]; }
1919
>'Hello' : "Hello"
2020

2121
var b = new Array<string>();
@@ -25,8 +25,8 @@ var b = new Array<string>();
2525

2626
b.concat('hello');
2727
>b.concat('hello') : string[]
28-
>b.concat : { (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; }
28+
>b.concat : { (...items: ConcatArray<string>[]): string[]; <U extends any[]>(...items: U): (string | ConcatFlatten<U[number]>)[]; }
2929
>b : string[]
30-
>concat : { (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; }
30+
>concat : { (...items: ConcatArray<string>[]): string[]; <U extends any[]>(...items: U): (string | ConcatFlatten<U[number]>)[]; }
3131
>'hello' : "hello"
3232

‎tests/baselines/reference/arrayConcat3.types

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -11,9 +11,9 @@ function doStuff<T extends object, T1 extends T>(a: Array<Fn<T>>, b: Array<Fn<T1
1111

1212
b.concat(a);
1313
>b.concat(a) : Fn<T1>[]
14-
>b.concat : { (...items: ConcatArray<Fn<T1>>[]): Fn<T1>[]; (...items: (Fn<T1> | ConcatArray<Fn<T1>>)[]): Fn<T1>[]; }
14+
>b.concat : { (...items: ConcatArray<Fn<T1>>[]): Fn<T1>[]; <U extends any[]>(...items: U): (Fn<T1> | ConcatFlatten<U[number]>)[]; }
1515
>b : Fn<T1>[]
16-
>concat : { (...items: ConcatArray<Fn<T1>>[]): Fn<T1>[]; (...items: (Fn<T1> | ConcatArray<Fn<T1>>)[]): Fn<T1>[]; }
16+
>concat : { (...items: ConcatArray<Fn<T1>>[]): Fn<T1>[]; <U extends any[]>(...items: U): (Fn<T1> | ConcatFlatten<U[number]>)[]; }
1717
>a : Fn<T>[]
1818
}
1919

‎tests/baselines/reference/arrayConcatMap.types

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -4,9 +4,9 @@ var x = [].concat([{ a: 1 }], [{ a: 2 }])
44
>[].concat([{ a: 1 }], [{ a: 2 }]) .map(b => b.a) : any[]
55
>[].concat([{ a: 1 }], [{ a: 2 }]) .map : <U>(callbackfn: (value: any, index: number, array: any[]) => U, thisArg?: any) => U[]
66
>[].concat([{ a: 1 }], [{ a: 2 }]) : any[]
7-
>[].concat : { (...items: ConcatArray<any>[]): any[]; (...items: any[]): any[]; }
7+
>[].concat : { (...items: ConcatArray<any>[]): any[]; <U extends any[]>(...items: U): any[]; }
88
>[] : undefined[]
9-
>concat : { (...items: ConcatArray<any>[]): any[]; (...items: any[]): any[]; }
9+
>concat : { (...items: ConcatArray<any>[]): any[]; <U extends any[]>(...items: U): any[]; }
1010
>[{ a: 1 }] : { a: number; }[]
1111
>{ a: 1 } : { a: number; }
1212
>a : number

‎tests/baselines/reference/arrayFlatMap.types

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -9,17 +9,17 @@ const readonlyArray: ReadonlyArray<number> = [];
99

1010
array.flatMap((): ReadonlyArray<number> => []); // ok
1111
>array.flatMap((): ReadonlyArray<number> => []) : number[]
12-
>array.flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | readonly U[], thisArg?: This) => U[]
12+
>array.flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U, thisArg?: This) => (U extends readonly (infer V)[] ? V : U)[]
1313
>array : number[]
14-
>flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | readonly U[], thisArg?: This) => U[]
14+
>flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U, thisArg?: This) => (U extends readonly (infer V)[] ? V : U)[]
1515
>(): ReadonlyArray<number> => [] : () => readonly number[]
1616
>[] : undefined[]
1717

1818
readonlyArray.flatMap((): ReadonlyArray<number> => []); // ok
1919
>readonlyArray.flatMap((): ReadonlyArray<number> => []) : number[]
20-
>readonlyArray.flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | readonly U[], thisArg?: This) => U[]
20+
>readonlyArray.flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U, thisArg?: This) => (U extends readonly (infer V)[] ? V : U)[]
2121
>readonlyArray : readonly number[]
22-
>flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | readonly U[], thisArg?: This) => U[]
22+
>flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U, thisArg?: This) => (U extends readonly (infer V)[] ? V : U)[]
2323
>(): ReadonlyArray<number> => [] : () => readonly number[]
2424
>[] : undefined[]
2525

‎tests/baselines/reference/arrayOfSubtypeIsAssignableToReadonlyArray.errors.txt

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(13,1): error TS2322: Type 'A[]' is not assignable to type 'readonly B[]'.
22
Property 'b' is missing in type 'A' but required in type 'B'.
33
tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(18,1): error TS2322: Type 'C<A>' is not assignable to type 'readonly B[]'.
4-
The types returned by 'concat(...)' are incompatible between these types.
4+
The types returned by 'slice(...)' are incompatible between these types.
55
Type 'A[]' is not assignable to type 'B[]'.
66
Type 'A' is not assignable to type 'B'.
77

@@ -31,7 +31,7 @@ tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(18,1): error T
3131
rrb = cra; // error: 'A' is not assignable to 'B'
3232
~~~
3333
!!! error TS2322: Type 'C<A>' is not assignable to type 'readonly B[]'.
34-
!!! error TS2322: The types returned by 'concat(...)' are incompatible between these types.
34+
!!! error TS2322: The types returned by 'slice(...)' are incompatible between these types.
3535
!!! error TS2322: Type 'A[]' is not assignable to type 'B[]'.
3636
!!! error TS2322: Type 'A' is not assignable to type 'B'.
3737

‎tests/baselines/reference/concatError.types

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -15,19 +15,19 @@ fa = fa.concat([0]);
1515
>fa = fa.concat([0]) : number[]
1616
>fa : number[]
1717
>fa.concat([0]) : number[]
18-
>fa.concat : { (...items: ConcatArray<number>[]): number[]; (...items: (number | ConcatArray<number>)[]): number[]; }
18+
>fa.concat : { (...items: ConcatArray<number>[]): number[]; <U extends any[]>(...items: U): (number | ConcatFlatten<U[number]>)[]; }
1919
>fa : number[]
20-
>concat : { (...items: ConcatArray<number>[]): number[]; (...items: (number | ConcatArray<number>)[]): number[]; }
20+
>concat : { (...items: ConcatArray<number>[]): number[]; <U extends any[]>(...items: U): (number | ConcatFlatten<U[number]>)[]; }
2121
>[0] : number[]
2222
>0 : 0
2323

2424
fa = fa.concat(0);
2525
>fa = fa.concat(0) : number[]
2626
>fa : number[]
2727
>fa.concat(0) : number[]
28-
>fa.concat : { (...items: ConcatArray<number>[]): number[]; (...items: (number | ConcatArray<number>)[]): number[]; }
28+
>fa.concat : { (...items: ConcatArray<number>[]): number[]; <U extends any[]>(...items: U): (number | ConcatFlatten<U[number]>)[]; }
2929
>fa : number[]
30-
>concat : { (...items: ConcatArray<number>[]): number[]; (...items: (number | ConcatArray<number>)[]): number[]; }
30+
>concat : { (...items: ConcatArray<number>[]): number[]; <U extends any[]>(...items: U): (number | ConcatFlatten<U[number]>)[]; }
3131
>0 : 0
3232

3333

‎tests/baselines/reference/concatTuples.types

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -10,9 +10,9 @@ ijs = ijs.concat([[3, 4], [5, 6]]);
1010
>ijs = ijs.concat([[3, 4], [5, 6]]) : [number, number][]
1111
>ijs : [number, number][]
1212
>ijs.concat([[3, 4], [5, 6]]) : [number, number][]
13-
>ijs.concat : { (...items: ConcatArray<[number, number]>[]): [number, number][]; (...items: ([number, number] | ConcatArray<[number, number]>)[]): [number, number][]; }
13+
>ijs.concat : { (...items: ConcatArray<[number, number]>[]): [number, number][]; <U extends any[]>(...items: U): ([number, number] | ConcatFlatten<U[number]>)[]; }
1414
>ijs : [number, number][]
15-
>concat : { (...items: ConcatArray<[number, number]>[]): [number, number][]; (...items: ([number, number] | ConcatArray<[number, number]>)[]): [number, number][]; }
15+
>concat : { (...items: ConcatArray<[number, number]>[]): [number, number][]; <U extends any[]>(...items: U): ([number, number] | ConcatFlatten<U[number]>)[]; }
1616
>[[3, 4], [5, 6]] : [number, number][]
1717
>[3, 4] : [number, number]
1818
>3 : 3

‎tests/baselines/reference/contextualExpressionTypecheckingDoesntBlowStack.types

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -69,15 +69,15 @@ export default class Operation {
6969

7070
// Commenting out this line will fix the problem.
7171
result = (result || []).concat(innerResult);
72-
>result = (result || []).concat(innerResult) : IValidationError[]
72+
>result = (result || []).concat(innerResult) : any[]
7373
>result : IValidationError[] | null
74-
>(result || []).concat(innerResult) : IValidationError[]
75-
>(result || []).concat : { (...items: ConcatArray<IValidationError>[]): IValidationError[]; (...items: (IValidationError | ConcatArray<IValidationError>)[]): IValidationError[]; }
74+
>(result || []).concat(innerResult) : any[]
75+
>(result || []).concat : { (...items: ConcatArray<IValidationError>[]): IValidationError[]; <U extends any[]>(...items: U): (IValidationError | ConcatFlatten<U[number]>)[]; }
7676
>(result || []) : IValidationError[]
7777
>result || [] : IValidationError[]
7878
>result : IValidationError[] | null
7979
>[] : never[]
80-
>concat : { (...items: ConcatArray<IValidationError>[]): IValidationError[]; (...items: (IValidationError | ConcatArray<IValidationError>)[]): IValidationError[]; }
80+
>concat : { (...items: ConcatArray<IValidationError>[]): IValidationError[]; <U extends any[]>(...items: U): (IValidationError | ConcatFlatten<U[number]>)[]; }
8181
>innerResult : any
8282
}
8383
}

‎tests/baselines/reference/destructuringParameterDeclaration4.errors.txt

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -41,7 +41,7 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts(
4141
a1(...array2); // Error parameter type is (number|string)[]
4242
~~~~~~
4343
!!! error TS2552: Cannot find name 'array2'. Did you mean 'Array'?
44-
!!! related TS2728 /.ts/lib.es5.d.ts:1373:13: 'Array' is declared here.
44+
!!! related TS2728 /.ts/lib.es5.d.ts:1374:13: 'Array' is declared here.
4545
a5([1, 2, "string", false, true]); // Error, parameter type is [any, any, [[any]]]
4646
~~~~~~~~
4747
!!! error TS2322: Type 'string' is not assignable to type '[[any]]'.

‎tests/baselines/reference/destructuringTuple.errors.txt

Lines changed: 17 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -1,12 +1,13 @@
1-
tests/cases/compiler/destructuringTuple.ts(11,8): error TS2493: Tuple type '[]' of length '0' has no element at index '0'.
2-
tests/cases/compiler/destructuringTuple.ts(11,60): error TS2769: No overload matches this call.
3-
Overload 1 of 2, '(...items: ConcatArray<never>[]): never[]', gave the following error.
4-
Argument of type 'number' is not assignable to parameter of type 'ConcatArray<never>'.
5-
Overload 2 of 2, '(...items: ConcatArray<never>[]): never[]', gave the following error.
6-
Argument of type 'number' is not assignable to parameter of type 'ConcatArray<never>'.
1+
tests/cases/compiler/destructuringTuple.ts(11,48): error TS2769: No overload matches this call.
2+
Overload 1 of 3, '(callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number, initialValue: number): number', gave the following error.
3+
Type 'number[]' is not assignable to type 'number'.
4+
Overload 2 of 3, '(callbackfn: (previousValue: [], currentValue: number, currentIndex: number, array: number[]) => [], initialValue: []): []', gave the following error.
5+
Type 'number[]' is not assignable to type '[]'.
6+
Types of property 'length' are incompatible.
7+
Type 'number' is not assignable to type '0'.
78

89

9-
==== tests/cases/compiler/destructuringTuple.ts (2 errors) ====
10+
==== tests/cases/compiler/destructuringTuple.ts (1 errors) ====
1011
declare var tuple: [boolean, number, ...string[]];
1112

1213
const [a, b, c, ...rest] = tuple;
@@ -18,14 +19,16 @@ tests/cases/compiler/destructuringTuple.ts(11,60): error TS2769: No overload mat
1819
// Repros from #32140
1920

2021
const [oops1] = [1, 2, 3].reduce((accu, el) => accu.concat(el), []);
21-
~~~~~
22-
!!! error TS2493: Tuple type '[]' of length '0' has no element at index '0'.
23-
~~
22+
~~~~~~~~~~~~~~~
2423
!!! error TS2769: No overload matches this call.
25-
!!! error TS2769: Overload 1 of 2, '(...items: ConcatArray<never>[]): never[]', gave the following error.
26-
!!! error TS2769: Argument of type 'number' is not assignable to parameter of type 'ConcatArray<never>'.
27-
!!! error TS2769: Overload 2 of 2, '(...items: ConcatArray<never>[]): never[]', gave the following error.
28-
!!! error TS2769: Argument of type 'number' is not assignable to parameter of type 'ConcatArray<never>'.
24+
!!! error TS2769: Overload 1 of 3, '(callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number, initialValue: number): number', gave the following error.
25+
!!! error TS2769: Type 'number[]' is not assignable to type 'number'.
26+
!!! error TS2769: Overload 2 of 3, '(callbackfn: (previousValue: [], currentValue: number, currentIndex: number, array: number[]) => [], initialValue: []): []', gave the following error.
27+
!!! error TS2769: Type 'number[]' is not assignable to type '[]'.
28+
!!! error TS2769: Types of property 'length' are incompatible.
29+
!!! error TS2769: Type 'number' is not assignable to type '0'.
30+
!!! related TS6502 /.ts/lib.es5.d.ts:1339:24: The expected type comes from the return type of this signature.
31+
!!! related TS6502 /.ts/lib.es5.d.ts:1345:27: The expected type comes from the return type of this signature.
2932

3033
const [oops2] = [1, 2, 3].reduce((acc: number[], e) => acc.concat(e), []);
3134

‎tests/baselines/reference/destructuringTuple.types

Lines changed: 9 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -23,23 +23,23 @@ declare var receiver: typeof tuple;
2323
// Repros from #32140
2424

2525
const [oops1] = [1, 2, 3].reduce((accu, el) => accu.concat(el), []);
26-
>oops1 : undefined
27-
>[1, 2, 3].reduce((accu, el) => accu.concat(el), []) : []
26+
>oops1 : any
27+
>[1, 2, 3].reduce((accu, el) => accu.concat(el), []) : any
2828
>[1, 2, 3].reduce : { (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number): number; (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number, initialValue: number): number; <U>(callbackfn: (previousValue: U, currentValue: number, currentIndex: number, array: number[]) => U, initialValue: U): U; }
2929
>[1, 2, 3] : number[]
3030
>1 : 1
3131
>2 : 2
3232
>3 : 3
3333
>reduce : { (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number): number; (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number, initialValue: number): number; <U>(callbackfn: (previousValue: U, currentValue: number, currentIndex: number, array: number[]) => U, initialValue: U): U; }
34-
>(accu, el) => accu.concat(el) : (accu: [], el: number) => any
34+
>(accu, el) => accu.concat(el) : (accu: [], el: number) => number[]
3535
>accu : []
3636
>el : number
37-
>accu.concat(el) : any
38-
>accu.concat : { (...items: ConcatArray<never>[]): never[]; (...items: ConcatArray<never>[]): never[]; }
37+
>accu.concat(el) : number[]
38+
>accu.concat : { (...items: ConcatArray<never>[]): never[]; <U extends any[]>(...items: U): ConcatFlatten<U[number]>[]; }
3939
>accu : []
40-
>concat : { (...items: ConcatArray<never>[]): never[]; (...items: ConcatArray<never>[]): never[]; }
40+
>concat : { (...items: ConcatArray<never>[]): never[]; <U extends any[]>(...items: U): ConcatFlatten<U[number]>[]; }
4141
>el : number
42-
>[] : []
42+
>[] : never[]
4343

4444
const [oops2] = [1, 2, 3].reduce((acc: number[], e) => acc.concat(e), []);
4545
>oops2 : number
@@ -54,9 +54,9 @@ const [oops2] = [1, 2, 3].reduce((acc: number[], e) => acc.concat(e), []);
5454
>acc : number[]
5555
>e : number
5656
>acc.concat(e) : number[]
57-
>acc.concat : { (...items: ConcatArray<number>[]): number[]; (...items: (number | ConcatArray<number>)[]): number[]; }
57+
>acc.concat : { (...items: ConcatArray<number>[]): number[]; <U extends any[]>(...items: U): (number | ConcatFlatten<U[number]>)[]; }
5858
>acc : number[]
59-
>concat : { (...items: ConcatArray<number>[]): number[]; (...items: (number | ConcatArray<number>)[]): number[]; }
59+
>concat : { (...items: ConcatArray<number>[]): number[]; <U extends any[]>(...items: U): (number | ConcatFlatten<U[number]>)[]; }
6060
>e : number
6161
>[] : never[]
6262

‎tests/baselines/reference/emitSkipsThisWithRestParameter.types

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -18,10 +18,10 @@ function rebase(fn: (base: any, ...args: any[]) => any): (...args: any[]) => any
1818
>apply : (this: Function, thisArg: any, argArray?: any) => any
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>this : any
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>[ this ].concat(args) : any[]
21-
>[ this ].concat : { (...items: ConcatArray<any>[]): any[]; (...items: any[]): any[]; }
21+
>[ this ].concat : { (...items: ConcatArray<any>[]): any[]; <U extends any[]>(...items: U): any[]; }
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>[ this ] : any[]
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>this : any
24-
>concat : { (...items: ConcatArray<any>[]): any[]; (...items: any[]): any[]; }
24+
>concat : { (...items: ConcatArray<any>[]): any[]; <U extends any[]>(...items: U): any[]; }
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>args : any[]
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2727
};

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