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tests/cases/conformance/types/conditional/inferTypes1.ts(36,23): error TS2344: Type 'string' does not satisfy the constraint '(...args: any) => any'.
tests/cases/conformance/types/conditional/inferTypes1.ts(37,23): error TS2344: Type 'Function' does not satisfy the constraint '(...args: any) => any'.
Type 'Function' provides no match for the signature '(...args: any): any'.
tests/cases/conformance/types/conditional/inferTypes1.ts(43,25): error TS2344: Type 'string' does not satisfy the constraint 'abstract new (...args: any) => any'.
tests/cases/conformance/types/conditional/inferTypes1.ts(44,25): error TS2344: Type 'Function' does not satisfy the constraint 'abstract new (...args: any) => any'.
Type 'Function' provides no match for the signature 'new (...args: any): any'.
tests/cases/conformance/types/conditional/inferTypes1.ts(55,25): error TS2344: Type '(x: string, y: string) => number' does not satisfy the constraint '(x: any) => any'.
tests/cases/conformance/types/conditional/inferTypes1.ts(56,25): error TS2344: Type 'Function' does not satisfy the constraint '(x: any) => any'.
Type 'Function' provides no match for the signature '(x: any): any'.
tests/cases/conformance/types/conditional/inferTypes1.ts(82,12): error TS1338: 'infer' declarations are only permitted in the 'extends' clause of a conditional type.
tests/cases/conformance/types/conditional/inferTypes1.ts(83,16): error TS1338: 'infer' declarations are only permitted in the 'extends' clause of a conditional type.
tests/cases/conformance/types/conditional/inferTypes1.ts(83,43): error TS1338: 'infer' declarations are only permitted in the 'extends' clause of a conditional type.
tests/cases/conformance/types/conditional/inferTypes1.ts(83,53): error TS1338: 'infer' declarations are only permitted in the 'extends' clause of a conditional type.
tests/cases/conformance/types/conditional/inferTypes1.ts(84,15): error TS2304: Cannot find name 'U'.
tests/cases/conformance/types/conditional/inferTypes1.ts(84,15): error TS4081: Exported type alias 'T62' has or is using private name 'U'.
tests/cases/conformance/types/conditional/inferTypes1.ts(84,43): error TS2304: Cannot find name 'U'.
tests/cases/conformance/types/conditional/inferTypes1.ts(84,43): error TS4081: Exported type alias 'T62' has or is using private name 'U'.
tests/cases/conformance/types/conditional/inferTypes1.ts(91,44): error TS2344: Type 'U' does not satisfy the constraint 'string'.
Type 'number' is not assignable to type 'string'.
tests/cases/conformance/types/conditional/inferTypes1.ts(153,40): error TS2322: Type 'T' is not assignable to type 'string | number | symbol'.
==== tests/cases/conformance/types/conditional/inferTypes1.ts (16 errors) ====
type Unpacked<T> =
T extends (infer U)[] ? U :
T extends (...args: any[]) => infer U ? U :
T extends Promise<infer U> ? U :
T;
type T00 = Unpacked<string>; // string
type T01 = Unpacked<string[]>; // string
type T02 = Unpacked<() => string>; // string
type T03 = Unpacked<Promise<string>>; // string
type T04 = Unpacked<Unpacked<Promise<string>[]>>; // string
type T05 = Unpacked<any>; // any
type T06 = Unpacked<never>; // never
function f1(s: string) {
return { a: 1, b: s };
}
class C {
x = 0;
y = 0;
}
abstract class Abstract {
x = 0;
y = 0;
}
type T10 = ReturnType<() => string>; // string
type T11 = ReturnType<(s: string) => void>; // void
type T12 = ReturnType<(<T>() => T)>; // {}
type T13 = ReturnType<(<T extends U, U extends number[]>() => T)>; // number[]
type T14 = ReturnType<typeof f1>; // { a: number, b: string }
type T15 = ReturnType<any>; // any
type T16 = ReturnType<never>; // never
type T17 = ReturnType<string>; // Error
~~~~~~
!!! error TS2344: Type 'string' does not satisfy the constraint '(...args: any) => any'.
type T18 = ReturnType<Function>; // Error
~~~~~~~~
!!! error TS2344: Type 'Function' does not satisfy the constraint '(...args: any) => any'.
!!! error TS2344: Type 'Function' provides no match for the signature '(...args: any): any'.
type T19<T extends any[]> = ReturnType<(x: string, ...args: T) => T[]>; // T[]
type U10 = InstanceType<typeof C>; // C
type U11 = InstanceType<any>; // any
type U12 = InstanceType<never>; // never
type U13 = InstanceType<string>; // Error
~~~~~~
!!! error TS2344: Type 'string' does not satisfy the constraint 'abstract new (...args: any) => any'.
type U14 = InstanceType<Function>; // Error
~~~~~~~~
!!! error TS2344: Type 'Function' does not satisfy the constraint 'abstract new (...args: any) => any'.
!!! error TS2344: Type 'Function' provides no match for the signature 'new (...args: any): any'.
type U15 = InstanceType<typeof Abstract>; // Abstract
type U16<T extends any[]> = InstanceType<new (x: string, ...args: T) => T[]>; // T[]
type U17<T extends any[]> = InstanceType<abstract new (x: string, ...args: T) => T[]>; // T[]
type ArgumentType<T extends (x: any) => any> = T extends (a: infer A) => any ? A : any;
type T20 = ArgumentType<() => void>; // {}
type T21 = ArgumentType<(x: string) => number>; // string
type T22 = ArgumentType<(x?: string) => number>; // string | undefined
type T23 = ArgumentType<(...args: string[]) => number>; // string
type T24 = ArgumentType<(x: string, y: string) => number>; // Error
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! error TS2344: Type '(x: string, y: string) => number' does not satisfy the constraint '(x: any) => any'.
type T25 = ArgumentType<Function>; // Error
~~~~~~~~
!!! error TS2344: Type 'Function' does not satisfy the constraint '(x: any) => any'.
!!! error TS2344: Type 'Function' provides no match for the signature '(x: any): any'.
type T26 = ArgumentType<any>; // any
type T27 = ArgumentType<never>; // never
type X1<T extends { x: any, y: any }> = T extends { x: infer X, y: infer Y } ? [X, Y] : any;
type T30 = X1<{ x: any, y: any }>; // [any, any]
type T31 = X1<{ x: number, y: string }>; // [number, string]
type T32 = X1<{ x: number, y: string, z: boolean }>; // [number, string]
type X2<T> = T extends { a: infer U, b: infer U } ? U : never;
type T40 = X2<{}>; // never
type T41 = X2<{ a: string }>; // never
type T42 = X2<{ a: string, b: string }>; // string
type T43 = X2<{ a: number, b: string }>; // string | number
type T44 = X2<{ a: number, b: string, c: boolean }>; // string | number
type X3<T> = T extends { a: (x: infer U) => void, b: (x: infer U) => void } ? U : never;
type T50 = X3<{}>; // never
type T51 = X3<{ a: (x: string) => void }>; // never
type T52 = X3<{ a: (x: string) => void, b: (x: string) => void }>; // string
type T53 = X3<{ a: (x: number) => void, b: (x: string) => void }>; // never
type T54 = X3<{ a: (x: number) => void, b: () => void }>; // number
type T60 = infer U; // Error
~~~~~~~
!!! error TS1338: 'infer' declarations are only permitted in the 'extends' clause of a conditional type.
type T61<T> = (infer A) extends infer B ? infer C : infer D; // Error
~~~~~~~
!!! error TS1338: 'infer' declarations are only permitted in the 'extends' clause of a conditional type.
~~~~~~~
!!! error TS1338: 'infer' declarations are only permitted in the 'extends' clause of a conditional type.
~~~~~~~
!!! error TS1338: 'infer' declarations are only permitted in the 'extends' clause of a conditional type.
type T62<T> = U extends (infer U)[] ? U : U; // Error
~
!!! error TS2304: Cannot find name 'U'.
~
!!! error TS4081: Exported type alias 'T62' has or is using private name 'U'.
~
!!! error TS2304: Cannot find name 'U'.
~
!!! error TS4081: Exported type alias 'T62' has or is using private name 'U'.
type T63<T> = T extends ((infer A) extends infer B ? infer C : infer D) ? string : number;
type T70<T extends string> = { x: T };
type T71<T> = T extends T70<infer U> ? T70<U> : never;
type T72<T extends number> = { y: T };
type T73<T> = T extends T72<infer U> ? T70<U> : never; // Error
~
!!! error TS2344: Type 'U' does not satisfy the constraint 'string'.
!!! error TS2344: Type 'number' is not assignable to type 'string'.
type T74<T extends number, U extends string> = { x: T, y: U };
type T75<T> = T extends T74<infer U, infer U> ? T70<U> | T72<U> | T74<U, U> : never;
type T76<T extends T[], U extends T> = { x: T };
type T77<T> = T extends T76<infer X, infer Y> ? T76<X, Y> : never;
type T78<T> = T extends T76<infer X, infer X> ? T76<X, X> : never;
type Foo<T extends string, U extends T> = [T, U];
type Bar<T> = T extends Foo<infer X, infer Y> ? Foo<X, Y> : never;
type T90 = Bar<[string, string]>; // [string, string]
type T91 = Bar<[string, "a"]>; // [string, "a"]
type T92 = Bar<[string, "a"] & { x: string }>; // [string, "a"]
type T93 = Bar<["a", string]>; // never
type T94 = Bar<[number, number]>; // never
// Example from #21496
type JsonifiedObject<T extends object> = { [K in keyof T]: Jsonified<T[K]> };
type Jsonified<T> =
T extends string | number | boolean | null ? T
: T extends undefined | Function ? never // undefined and functions are removed
: T extends { toJSON(): infer R } ? R // toJSON is called if it exists (e.g. Date)
: T extends object ? JsonifiedObject<T>
: "what is this";
type Example = {
str: "literalstring",
fn: () => void,
date: Date,
customClass: MyClass,
obj: {
prop: "property",
clz: MyClass,
nested: { attr: Date }
},
}
declare class MyClass {
toJSON(): "correct";
}
type JsonifiedExample = Jsonified<Example>;
declare let ex: JsonifiedExample;
const z1: "correct" = ex.customClass;
const z2: string = ex.obj.nested.attr;
// Repros from #21631
type A1<T, U extends A1<any, any>> = [T, U];
type B1<S> = S extends A1<infer T, infer U> ? [T, U] : never;
type A2<T, U extends void> = [T, U];
type B2<S> = S extends A2<infer T, infer U> ? [T, U] : never;
type C2<S, U extends void> = S extends A2<infer T, U> ? [T, U] : never;
// Repro from #21735
type A<T> = T extends string ? { [P in T]: void; } : T;
type B<T> = string extends T ? { [P in T]: void; } : T; // Error
~
!!! error TS2322: Type 'T' is not assignable to type 'string | number | symbol'.
!!! related TS2208 tests/cases/conformance/types/conditional/inferTypes1.ts:153:8: This type parameter might need an `extends string | number | symbol` constraint.
// Repro from #22302
type MatchingKeys<T, U, K extends keyof T = keyof T> =
K extends keyof T ? T[K] extends U ? K : never : never;
type VoidKeys<T> = MatchingKeys<T, void>;
interface test {
a: 1,
b: void
}
type T80 = MatchingKeys<test, void>;
type T81 = VoidKeys<test>;
// Repro from #22221
type MustBeString<T extends string> = T;
type EnsureIsString<T> = T extends MustBeString<infer U> ? U : never;
type Test1 = EnsureIsString<"hello">; // "hello"
type Test2 = EnsureIsString<42>; // never
// Repros from #26856
function invoker <K extends string | number | symbol, A extends any[]> (key: K, ...args: A) {
return <T extends Record<K, (...args: A) => any>> (obj: T): ReturnType<T[K]> => obj[key](...args)
}
const result = invoker('test', true)({ test: (a: boolean) => 123 })
type Foo2<A extends any[]> = ReturnType<(...args: A) => string>;
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