TypeScript/tests/baselines/reference/neverType.types

=== tests/cases/conformance/types/never/neverType.ts ===


function error(message: string): never {
>error : (message: string) => never
>message : string

    throw new Error(message);
>new Error(message) : Error
>Error : ErrorConstructor
>message : string
}

function errorVoid(message: string) {
>errorVoid : (message: string) => void
>message : string

    throw new Error(message);
>new Error(message) : Error
>Error : ErrorConstructor
>message : string
}

function fail() {
>fail : () => never

    return error("Something failed");
>error("Something failed") : never
>error : (message: string) => never
>"Something failed" : string
}

function failOrThrow(shouldFail: boolean) {
>failOrThrow : (shouldFail: boolean) => never
>shouldFail : boolean

    if (shouldFail) {
>shouldFail : boolean

        return fail();
>fail() : never
>fail : () => never
    }
    throw new Error();
>new Error() : Error
>Error : ErrorConstructor
}

function infiniteLoop1() {
>infiniteLoop1 : () => void

    while (true) {
>true : boolean
    }
}

function infiniteLoop2(): never {
>infiniteLoop2 : () => never

    while (true) {
>true : boolean
    }
}

function move1(direction: "up" | "down") {
>move1 : (direction: "up" | "down") => number
>direction : "up" | "down"

    switch (direction) {
>direction : "up" | "down"

        case "up":
>"up" : string

            return 1;
>1 : number

        case "down":
>"down" : string

            return -1; 
>-1 : number
>1 : number
    }
    return error("Should never get here");
>error("Should never get here") : never
>error : (message: string) => never
>"Should never get here" : string
}

function move2(direction: "up" | "down") {
>move2 : (direction: "up" | "down") => number
>direction : "up" | "down"

    return direction === "up" ? 1 :
>direction === "up" ? 1 :        direction === "down" ? -1 :        error("Should never get here") : number
>direction === "up" : boolean
>direction : "up" | "down"
>"up" : string
>1 : number

        direction === "down" ? -1 :
>direction === "down" ? -1 :        error("Should never get here") : number
>direction === "down" : boolean
>direction : "up" | "down"
>"down" : string
>-1 : number
>1 : number

        error("Should never get here");
>error("Should never get here") : never
>error : (message: string) => never
>"Should never get here" : string
}

function check<T>(x: T | undefined) {
>check : <T>(x: T | undefined) => T
>T : T
>x : T | undefined
>T : T

    return x || error("Undefined value");
>x || error("Undefined value") : T
>x : T | undefined
>error("Undefined value") : never
>error : (message: string) => never
>"Undefined value" : string
}

class C {
>C : C

    void1() {
>void1 : () => void

        throw new Error();
>new Error() : Error
>Error : ErrorConstructor
    }
    void2() {
>void2 : () => void

        while (true) {}
>true : boolean
    }
    never1(): never {
>never1 : () => never

        throw new Error();
>new Error() : Error
>Error : ErrorConstructor
    }
    never2(): never {
>never2 : () => never

        while (true) {}
>true : boolean
    }
}

function f1(x: string | number) {
>f1 : (x: string | number) => void
>x : string | number

    if (typeof x === "boolean") {
>typeof x === "boolean" : boolean
>typeof x : string
>x : string | number
>"boolean" : string

        x;  // never
>x : never
    }
}

function f2(x: string | number) {
>f2 : (x: string | number) => never
>x : string | number

    while (true) {
>true : boolean

        if (typeof x === "boolean") {
>typeof x === "boolean" : boolean
>typeof x : string
>x : string | number
>"boolean" : string

            return x;  // never
>x : never
        }
    }
}

function test(cb: () => string) {
>test : (cb: () => string) => string
>cb : () => string

    let s = cb();
>s : string
>cb() : string
>cb : () => string

    return s;
>s : string
}

let errorCallback = () => error("Error callback");
>errorCallback : () => never
>() => error("Error callback") : () => never
>error("Error callback") : never
>error : (message: string) => never
>"Error callback" : string

test(() => "hello");
>test(() => "hello") : string
>test : (cb: () => string) => string
>() => "hello" : () => string
>"hello" : string

test(() => fail());
>test(() => fail()) : string
>test : (cb: () => string) => string
>() => fail() : () => never
>fail() : never
>fail : () => never

test(() => { throw new Error(); })
>test(() => { throw new Error(); }) : string
>test : (cb: () => string) => string
>() => { throw new Error(); } : () => never
>new Error() : Error
>Error : ErrorConstructor

test(errorCallback);
>test(errorCallback) : string
>test : (cb: () => string) => string
>errorCallback : () => never