TypeScript/tests/baselines/reference/inferTypes1.types

=== tests/cases/conformance/types/conditional/inferTypes1.ts ===
type Unpacked<T> =
>Unpacked : Unpacked<T>

    T extends (infer U)[] ? U :
    T extends (...args: any[]) => infer U ? U :
>args : any[]

    T extends Promise<infer U> ? U :
    T;

type T00 = Unpacked<string>;  // string
>T00 : string

type T01 = Unpacked<string[]>;  // string
>T01 : string

type T02 = Unpacked<() => string>;  // string
>T02 : string

type T03 = Unpacked<Promise<string>>;  // string
>T03 : string

type T04 = Unpacked<Unpacked<Promise<string>[]>>;  // string
>T04 : string

type T05 = Unpacked<any>;  // any
>T05 : any

type T06 = Unpacked<never>;  // never
>T06 : never

function f1(s: string) {
>f1 : (s: string) => { a: number; b: string; }
>s : string

    return { a: 1, b: s };
>{ a: 1, b: s } : { a: number; b: string; }
>a : number
>1 : 1
>b : string
>s : string
}

class C {
>C : C

    x = 0;
>x : number
>0 : 0

    y = 0;
>y : number
>0 : 0
}

abstract class Abstract {
>Abstract : Abstract

    x = 0;
>x : number
>0 : 0

    y = 0;
>y : number
>0 : 0
}

type T10 = ReturnType<() => string>;  // string
>T10 : string

type T11 = ReturnType<(s: string) => void>;  // void
>T11 : void
>s : string

type T12 = ReturnType<(<T>() => T)>;  // {}
>T12 : unknown

type T13 = ReturnType<(<T extends U, U extends number[]>() => T)>;  // number[]
>T13 : number[]

type T14 = ReturnType<typeof f1>;  // { a: number, b: string }
>T14 : { a: number; b: string; }
>f1 : (s: string) => { a: number; b: string; }

type T15 = ReturnType<any>;  // any
>T15 : any

type T16 = ReturnType<never>;  // never
>T16 : never

type T17 = ReturnType<string>;  // Error
>T17 : any

type T18 = ReturnType<Function>;  // Error
>T18 : any

type T19<T extends any[]> = ReturnType<(x: string, ...args: T) => T[]>;  // T[]
>T19 : T[]
>x : string
>args : T

type U10 = InstanceType<typeof C>;  // C
>U10 : C
>C : typeof C

type U11 = InstanceType<any>;  // any
>U11 : any

type U12 = InstanceType<never>;  // never
>U12 : never

type U13 = InstanceType<string>;  // Error
>U13 : any

type U14 = InstanceType<Function>;  // Error
>U14 : any

type U15 = InstanceType<typeof Abstract>;  // Abstract
>U15 : Abstract
>Abstract : typeof Abstract

type U16<T extends any[]> = InstanceType<new (x: string, ...args: T) => T[]>;  // T[]
>U16 : T[]
>x : string
>args : T

type U17<T extends any[]> = InstanceType<abstract new (x: string, ...args: T) => T[]>;  // T[]
>U17 : T[]
>x : string
>args : T

type ArgumentType<T extends (x: any) => any> = T extends (a: infer A) => any ? A : any;
>ArgumentType : ArgumentType<T>
>x : any
>a : A

type T20 = ArgumentType<() => void>;  // {}
>T20 : unknown

type T21 = ArgumentType<(x: string) => number>;  // string
>T21 : string
>x : string

type T22 = ArgumentType<(x?: string) => number>;  // string | undefined
>T22 : string | undefined
>x : string | undefined

type T23 = ArgumentType<(...args: string[]) => number>;  // string
>T23 : string
>args : string[]

type T24 = ArgumentType<(x: string, y: string) => number>;  // Error
>T24 : any
>x : string
>y : string

type T25 = ArgumentType<Function>;  // Error
>T25 : any

type T26 = ArgumentType<any>;  // any
>T26 : any

type T27 = ArgumentType<never>;  // never
>T27 : never

type X1<T extends { x: any, y: any }> = T extends { x: infer X, y: infer Y } ? [X, Y] : any;
>X1 : X1<T>
>x : any
>y : any
>x : X
>y : Y

type T30 = X1<{ x: any, y: any }>;  // [any, any]
>T30 : [any, any]
>x : any
>y : any

type T31 = X1<{ x: number, y: string }>;  // [number, string]
>T31 : [number, string]
>x : number
>y : string

type T32 = X1<{ x: number, y: string, z: boolean }>;  // [number, string]
>T32 : [number, string]
>x : number
>y : string
>z : boolean

type X2<T> = T extends { a: infer U, b: infer U } ? U : never;
>X2 : X2<T>
>a : U
>b : U

type T40 = X2<{}>;  // never
>T40 : never

type T41 = X2<{ a: string }>;  // never
>T41 : never
>a : string

type T42 = X2<{ a: string, b: string }>;  // string
>T42 : string
>a : string
>b : string

type T43 = X2<{ a: number, b: string }>;  // string | number
>T43 : string | number
>a : number
>b : string

type T44 = X2<{ a: number, b: string, c: boolean }>;  // string | number
>T44 : string | number
>a : number
>b : string
>c : boolean

type X3<T> = T extends { a: (x: infer U) => void, b: (x: infer U) => void } ? U : never;
>X3 : X3<T>
>a : (x: infer U) => void
>x : U
>b : (x: infer U) => void
>x : U

type T50 = X3<{}>;  // never
>T50 : never

type T51 = X3<{ a: (x: string) => void }>;  // never
>T51 : never
>a : (x: string) => void
>x : string

type T52 = X3<{ a: (x: string) => void, b: (x: string) => void }>;  // string
>T52 : string
>a : (x: string) => void
>x : string
>b : (x: string) => void
>x : string

type T53 = X3<{ a: (x: number) => void, b: (x: string) => void }>;  // never
>T53 : never
>a : (x: number) => void
>x : number
>b : (x: string) => void
>x : string

type T54 = X3<{ a: (x: number) => void, b: () => void }>;  // number
>T54 : number
>a : (x: number) => void
>x : number
>b : () => void

type T60 = infer U;  // Error
>T60 : U

type T61<T> = infer A extends infer B ? infer C : infer D;  // Error
>T61 : T61<T>

type T62<T> = U extends (infer U)[] ? U : U;  // Error
>T62 : any

type T63<T> = T extends (infer A extends infer B ? infer C : infer D) ? string : number;
>T63 : T63<T>

type T70<T extends string> = { x: T };
>T70 : T70<T>
>x : T

type T71<T> = T extends T70<infer U> ? T70<U> : never;
>T71 : T71<T>

type T72<T extends number> = { y: T };
>T72 : T72<T>
>y : T

type T73<T> = T extends T72<infer U> ? T70<U> : never;  // Error
>T73 : T73<T>

type T74<T extends number, U extends string> = { x: T, y: U };
>T74 : T74<T, U>
>x : T
>y : U

type T75<T> = T extends T74<infer U, infer U> ? T70<U> | T72<U> | T74<U, U> : never;
>T75 : T75<T>

type T76<T extends T[], U extends T> = { x: T };
>T76 : T76<T, U>
>x : T

type T77<T> = T extends T76<infer X, infer Y> ? T76<X, Y> : never;
>T77 : T77<T>

type T78<T> = T extends T76<infer X, infer X> ? T76<X, X> : never;
>T78 : T78<T>

type Foo<T extends string, U extends T> = [T, U];
>Foo : Foo<T, U>

type Bar<T> = T extends Foo<infer X, infer Y> ? Foo<X, Y> : never;
>Bar : Bar<T>

type T90 = Bar<[string, string]>;  // [string, string]
>T90 : Foo<string, string>

type T91 = Bar<[string, "a"]>;  // [string, "a"]
>T91 : Foo<string, "a">

type T92 = Bar<[string, "a"] & { x: string }>;  // [string, "a"]
>T92 : Foo<string, "a">
>x : string

type T93 = Bar<["a", string]>;  // never
>T93 : never

type T94 = Bar<[number, number]>;  // never
>T94 : never

// Example from #21496

type JsonifiedObject<T extends object> = { [K in keyof T]: Jsonified<T[K]> };
>JsonifiedObject : JsonifiedObject<T>

type Jsonified<T> =
>Jsonified : Jsonified<T>

    T extends string | number | boolean | null ? T
>null : null

    : 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)
>toJSON : () => infer R

    : T extends object ? JsonifiedObject<T>
    : "what is this";

type Example = {
>Example : Example

    str: "literalstring",
>str : "literalstring"

    fn: () => void,
>fn : () => void

    date: Date,
>date : Date

    customClass: MyClass,
>customClass : MyClass

    obj: {
>obj : { prop: "property"; clz: MyClass; nested: {    attr: Date;}; }

        prop: "property",
>prop : "property"

        clz: MyClass,
>clz : MyClass

        nested: { attr: Date }
>nested : { attr: Date; }
>attr : Date

    },
}

declare class MyClass {
>MyClass : MyClass

    toJSON(): "correct";
>toJSON : () => "correct"
}

type JsonifiedExample = Jsonified<Example>;
>JsonifiedExample : JsonifiedObject<Example>

declare let ex: JsonifiedExample;
>ex : JsonifiedObject<Example>

const z1: "correct" = ex.customClass;
>z1 : "correct"
>ex.customClass : "correct"
>ex : JsonifiedObject<Example>
>customClass : "correct"

const z2: string = ex.obj.nested.attr;
>z2 : string
>ex.obj.nested.attr : string
>ex.obj.nested : JsonifiedObject<{ attr: Date; }>
>ex.obj : JsonifiedObject<{ prop: "property"; clz: MyClass; nested: { attr: Date; }; }>
>ex : JsonifiedObject<Example>
>obj : JsonifiedObject<{ prop: "property"; clz: MyClass; nested: { attr: Date; }; }>
>nested : JsonifiedObject<{ attr: Date; }>
>attr : string

// Repros from #21631

type A1<T, U extends A1<any, any>> = [T, U];
>A1 : A1<T, U>

type B1<S> = S extends A1<infer T, infer U> ? [T, U] : never;
>B1 : B1<S>

type A2<T, U extends void> = [T, U];
>A2 : A2<T, U>

type B2<S> = S extends A2<infer T, infer U> ? [T, U] : never;
>B2 : B2<S>

type C2<S, U extends void> = S extends A2<infer T, U> ? [T, U] : never;
>C2 : C2<S, U>

// Repro from #21735

type A<T> = T extends string ? { [P in T]: void; } : T;
>A : A<T>

type B<T> = string extends T ? { [P in T]: void; } : T;  // Error
>B : B<T>

// Repro from #22302

type MatchingKeys<T, U, K extends keyof T = keyof T> =
>MatchingKeys : MatchingKeys<T, U, K>

    K extends keyof T ? T[K] extends U ? K : never : never;

type VoidKeys<T> = MatchingKeys<T, void>;
>VoidKeys : VoidKeys<T>

interface test {
    a: 1,
>a : 1

    b: void
>b : void
}

type T80 = MatchingKeys<test, void>;
>T80 : "b"

type T81 = VoidKeys<test>;
>T81 : "b"

// Repro from #22221

type MustBeString<T extends string> = T;
>MustBeString : T

type EnsureIsString<T> = T extends MustBeString<infer U> ? U : never;
>EnsureIsString : EnsureIsString<T>

type Test1 = EnsureIsString<"hello">;  // "hello"
>Test1 : "hello"

type Test2 = EnsureIsString<42>;  // never
>Test2 : never

// Repros from #26856

function invoker <K extends string | number | symbol, A extends any[]> (key: K, ...args: A) {
>invoker : <K extends string | number | symbol, A extends any[]>(key: K, ...args: A) => <T extends Record<K, (...args: A) => any>>(obj: T) => ReturnType<T[K]>
>key : K
>args : A

    return <T extends Record<K, (...args: A) => any>> (obj: T): ReturnType<T[K]> => obj[key](...args)
><T extends Record<K, (...args: A) => any>> (obj: T): ReturnType<T[K]> => obj[key](...args) : <T extends Record<K, (...args: A) => any>>(obj: T) => ReturnType<T[K]>
>args : A
>obj : T
>obj[key](...args) : any
>obj[key] : T[K]
>obj : T
>key : K
>...args : any
>args : A
}

const result = invoker('test', true)({ test: (a: boolean) => 123 })
>result : number
>invoker('test', true)({ test: (a: boolean) => 123 }) : number
>invoker('test', true) : <T extends Record<"test", (args_0: boolean) => any>>(obj: T) => ReturnType<T["test"]>
>invoker : <K extends string | number | symbol, A extends any[]>(key: K, ...args: A) => <T extends Record<K, (...args: A) => any>>(obj: T) => ReturnType<T[K]>
>'test' : "test"
>true : true
>{ test: (a: boolean) => 123 } : { test: (a: boolean) => number; }
>test : (a: boolean) => number
>(a: boolean) => 123 : (a: boolean) => number
>a : boolean
>123 : 123

type Foo2<A extends any[]> = ReturnType<(...args: A) => string>;
>Foo2 : string
>args : A