tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(10,1): error TS2454: Variable 'a' is used before being assigned.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(14,1): error TS2454: Variable 'b' is used before being assigned.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(18,1): error TS2454: Variable 'c' is used before being assigned.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(22,1): error TS2454: Variable 'd' is used before being assigned.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(35,5): error TS2722: Cannot invoke an object which is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(39,1): error TS2722: Cannot invoke an object which is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(52,5): error TS18048: 'o2' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(57,1): error TS18048: 'o2' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(68,5): error TS18048: 'o3' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(72,1): error TS18048: 'o3' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(83,5): error TS18048: 'o4.x' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(87,1): error TS18048: 'o4.x' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(104,5): error TS18048: 'o5.x' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(105,5): error TS18048: 'o5.x' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(105,5): error TS18048: 'o5.x.y.z' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(111,1): error TS18048: 'o5.x' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(112,1): error TS18048: 'o5.x' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(112,1): error TS18048: 'o5.x.y.z' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(130,5): error TS18048: 'o6' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(134,1): error TS18048: 'o6' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(208,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(211,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(214,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(217,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(220,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(223,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(238,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(241,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(244,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(271,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(274,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(277,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(307,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(310,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(319,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(322,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(331,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(334,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(337,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(340,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(343,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(346,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(349,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(352,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(358,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(367,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(370,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(379,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(418,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(421,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(430,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(433,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(442,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(451,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(454,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(463,9): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(498,13): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(501,13): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(515,13): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(518,13): error TS18048: 'o' is possibly 'undefined'.
tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(567,21): error TS18048: 'someOptionalObject' is possibly 'undefined'.


==== tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts (61 errors) ====
    // assignments in shortcutting chain
    declare const o: undefined | {
        [key: string]: any;
        [key: number]: any;
        (...args: any[]): any;
    };
    
    let a: number;
    o?.[a = 1];
    a.toString();
    ~
!!! error TS2454: Variable 'a' is used before being assigned.
    
    let b: number;
    o?.x[b = 1];
    b.toString();
    ~
!!! error TS2454: Variable 'b' is used before being assigned.
    
    let c: number;
    o?.(c = 1)
    c.toString();
    ~
!!! error TS2454: Variable 'c' is used before being assigned.
    
    let d: number;
    o?.x(d = 1);
    d.toString();
    ~
!!! error TS2454: Variable 'd' is used before being assigned.
    
    // type predicates
    declare const f: undefined | ((x: any) => x is number);
    declare const x: string | number;
    if (f?.(x)) {
        x; // number
        f; // (x: any) => x is number
        f(x);
    }
    else {
        x;
        f;
        f(x);
        ~
!!! error TS2722: Cannot invoke an object which is possibly 'undefined'.
    }
    x;
    f;
    f(x);
    ~
!!! error TS2722: Cannot invoke an object which is possibly 'undefined'.
    
    declare const o2: { f(x: any): x is number; } | undefined;
    if (o2?.f(x)) {
        x; // number
        o2.f; // (x: any) => x is number
        o2?.f;
        o2?.f(x);
    }
    else {
        x;
        o2;
        o2?.f;
        o2.f;
        ~~
!!! error TS18048: 'o2' is possibly 'undefined'.
    }
    x;
    o2;
    o2?.f;
    o2.f;
    ~~
!!! error TS18048: 'o2' is possibly 'undefined'.
    
    declare const o3: { x: 1, y: string } | { x: 2, y: number } | undefined;
    if (o3?.x === 1) {
        o3;
        o3.x;
        o3?.x;
    }
    else {
        o3;
        o3?.x;
        o3.x;
        ~~
!!! error TS18048: 'o3' is possibly 'undefined'.
    }
    o3;
    o3?.x;
    o3.x;
    ~~
!!! error TS18048: 'o3' is possibly 'undefined'.
    
    declare const o4: { x?: { y: boolean } };
    if (o4.x?.y) {
        o4.x; // { y: boolean }
        o4.x.y; // true
        o4.x?.y; // true
    }
    else {
        o4.x;
        o4.x?.y;
        o4.x.y;
        ~~~~
!!! error TS18048: 'o4.x' is possibly 'undefined'.
    }
    o4.x;
    o4.x?.y;
    o4.x.y;
    ~~~~
!!! error TS18048: 'o4.x' is possibly 'undefined'.
    
    declare const o5: { x?: { y: { z?: { w: boolean } } } };
    if (o5.x?.y.z?.w) {
        o5.x;
        o5.x.y;
        o5.x.y.z;
        o5.x.y.z.w; // true
        o5.x.y.z?.w; // true
        o5.x?.y.z.w; // true
        o5.x?.y.z?.w; // true
    }
    else {
        o5.x;
        o5.x?.y;
        o5.x?.y.z;
        o5.x?.y.z?.w;
        o5.x.y;
        ~~~~
!!! error TS18048: 'o5.x' is possibly 'undefined'.
        o5.x.y.z.w;
        ~~~~
!!! error TS18048: 'o5.x' is possibly 'undefined'.
        ~~~~~~~~
!!! error TS18048: 'o5.x.y.z' is possibly 'undefined'.
    }
    o5.x;
    o5.x?.y;
    o5.x?.y.z;
    o5.x?.y.z?.w;
    o5.x.y;
    ~~~~
!!! error TS18048: 'o5.x' is possibly 'undefined'.
    o5.x.y.z.w;
    ~~~~
!!! error TS18048: 'o5.x' is possibly 'undefined'.
    ~~~~~~~~
!!! error TS18048: 'o5.x.y.z' is possibly 'undefined'.
    
    interface Base {
        f(): this is Derived;
    }
    
    interface Derived extends Base {
        x: number;
    }
    
    declare const o6: Base | undefined;
    if (o6?.f()) {
        o6; // Derived
        o6.f;
    }
    else {
        o6;
        o6?.f;
        o6.f;
        ~~
!!! error TS18048: 'o6' is possibly 'undefined'.
    }
    o6;
    o6?.f;
    o6.f;
    ~~
!!! error TS18048: 'o6' is possibly 'undefined'.
    
    // asserts
    declare const isDefined: <T>(value: T) => asserts value is NonNullable<T>;
    declare const isString: (value: unknown) => asserts value is string;
    declare const maybeIsString: undefined | ((value: unknown) => asserts value is string);
    declare const maybeNever: undefined | (() => never);
    
    function f01(x: unknown) {
        if (!!true) {
            isString?.(x);
            x;
        }
        if (!!true) {
            maybeIsString?.(x);
            x;
        }
        if (!!true) {
            isDefined(maybeIsString);
            maybeIsString?.(x);
            x;
        }
        if (!!true) {
            maybeNever?.();
            x;
        }
    }
    
    type Thing = { foo: string | number, bar(): number, baz: object };
    
    function f10(o: Thing | undefined, value: number) {
        if (o?.foo === value) {
            o.foo;
        }
        if (o?.["foo"] === value) {
            o["foo"];
        }
        if (o?.bar() === value) {
            o.bar;
        }
        if (o?.foo == value) {
            o.foo;
        }
        if (o?.["foo"] == value) {
            o["foo"];
        }
        if (o?.bar() == value) {
            o.bar;
        }
    }
    
    function f11(o: Thing | null, value: number) {
        if (o?.foo === value) {
            o.foo;
        }
        if (o?.["foo"] === value) {
            o["foo"];
        }
        if (o?.bar() === value) {
            o.bar;
        }
        if (o?.foo == value) {
            o.foo;
        }
        if (o?.["foo"] == value) {
            o["foo"];
        }
        if (o?.bar() == value) {
            o.bar;
        }
    }
    
    function f12(o: Thing | undefined, value: number | undefined) {
        if (o?.foo === value) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.["foo"] === value) {
            o["foo"];  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.bar() === value) {
            o.bar;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.foo == value) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.["foo"] == value) {
            o["foo"];  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.bar() == value) {
            o.bar;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
    }
    
    function f12a(o: Thing | undefined, value: number | null) {
        if (o?.foo === value) {
            o.foo;
        }
        if (o?.["foo"] === value) {
            o["foo"];
        }
        if (o?.bar() === value) {
            o.bar;
        }
        if (o?.foo == value) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.["foo"] == value) {
            o["foo"];  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.bar() == value) {
            o.bar;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
    }
    
    function f13(o: Thing | undefined) {
        if (o?.foo !== undefined) {
            o.foo;
        }
        if (o?.["foo"] !== undefined) {
            o["foo"];
        }
        if (o?.bar() !== undefined) {
            o.bar;
        }
        if (o?.foo != undefined) {
            o.foo;
        }
        if (o?.["foo"] != undefined) {
            o["foo"];
        }
        if (o?.bar() != undefined) {
            o.bar;
        }
    }
    
    function f13a(o: Thing | undefined) {
        if (o?.foo !== null) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.["foo"] !== null) {
            o["foo"];  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.bar() !== null) {
            o.bar;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.foo != null) {
            o.foo;
        }
        if (o?.["foo"] != null) {
            o["foo"];
        }
        if (o?.bar() != null) {
            o.bar;
        }
    }
    
    function f14(o: Thing | null) {
        if (o?.foo !== undefined) {
            o.foo;
        }
        if (o?.["foo"] !== undefined) {
            o["foo"];
        }
        if (o?.bar() !== undefined) {
            o.bar;
        }
    }
    
    function f15(o: Thing | undefined, value: number) {
        if (o?.foo === value) {
            o.foo;
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.foo !== value) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;
        }
        if (o?.foo == value) {
            o.foo;
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.foo != value) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;
        }
    }
    
    function f15a(o: Thing | undefined, value: unknown) {
        if (o?.foo === value) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.foo !== value) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.foo == value) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.foo != value) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
    }
    
    function f16(o: Thing | undefined) {
        if (o?.foo === undefined) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;
        }
        if (o?.foo !== undefined) {
            o.foo;
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (o?.foo == undefined) {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;
        }
        if (o?.foo != undefined) {
            o.foo;
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
    }
    
    function f20(o: Thing | undefined) {
        if (typeof o?.foo === "number") {
            o.foo;
        }
        if (typeof o?.["foo"] === "number") {
            o["foo"];
        }
        if (typeof o?.bar() === "number") {
            o.bar;
        }
        if (o?.baz instanceof Error) {
            o.baz;
        }
    }
    
    function f21(o: Thing | null) {
        if (typeof o?.foo === "number") {
            o.foo;
        }
        if (typeof o?.["foo"] === "number") {
            o["foo"];
        }
        if (typeof o?.bar() === "number") {
            o.bar;
        }
        if (o?.baz instanceof Error) {
            o.baz;
        }
    }
    
    function f22(o: Thing | undefined) {
        if (typeof o?.foo === "number") {
            o.foo;
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (typeof o?.foo !== "number") {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;
        }
        if (typeof o?.foo == "number") {
            o.foo;
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (typeof o?.foo != "number") {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;
        }
    }
    
    function f23(o: Thing | undefined) {
        if (typeof o?.foo === "undefined") {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;
        }
        if (typeof o?.foo !== "undefined") {
            o.foo;
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        if (typeof o?.foo == "undefined") {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
        else {
            o.foo;
        }
        if (typeof o?.foo != "undefined") {
            o.foo;
        }
        else {
            o.foo;  // Error
            ~
!!! error TS18048: 'o' is possibly 'undefined'.
        }
    }
    
    declare function assert(x: unknown): asserts x;
    declare function assertNonNull<T>(x: T): asserts x is NonNullable<T>;
    
    function f30(o: Thing | undefined) {
        if (!!true) {
            assert(o?.foo);
            o.foo;
        }
        if (!!true) {
            assert(o?.foo === 42);
            o.foo;
        }
        if (!!true) {
            assert(typeof o?.foo === "number");
            o.foo;
        }
        if (!!true) {
            assertNonNull(o?.foo);
            o.foo;
        }
    }
    
    function f40(o: Thing | undefined) {
        switch (o?.foo) {
            case "abc":
                o.foo;
                break;
            case 42:
                o.foo;
                break;
            case undefined:
                o.foo;  // Error
                ~
!!! error TS18048: 'o' is possibly 'undefined'.
                break;
            default:
                o.foo;  // Error
                ~
!!! error TS18048: 'o' is possibly 'undefined'.
                break;
        }
    }
    
    function f41(o: Thing | undefined) {
        switch (typeof o?.foo) {
            case "string":
                o.foo;
                break;
            case "number":
                o.foo;
                break;
            case "undefined":
                o.foo;  // Error
                ~
!!! error TS18048: 'o' is possibly 'undefined'.
                break;
            default:
                o.foo;  // Error
                ~
!!! error TS18048: 'o' is possibly 'undefined'.
                break;
        }
    }
    
    // Repros from #34570
    
    type Shape =
        | { type: 'rectangle', width: number, height: number }
        | { type: 'circle', radius: number }
    
    function getArea(shape?: Shape) {
        switch (shape?.type) {
            case 'circle':
                return Math.PI * shape.radius ** 2
            case 'rectangle':
                return shape.width * shape.height
            default:
                return 0
        }
    }
    
    type Feature = {
      id: string;
      geometry?: {
        type: string;
        coordinates: number[];
      };
    };
    
    
    function extractCoordinates(f: Feature): number[] {
        if (f.geometry?.type !== 'test') {
            return [];
        }
        return f.geometry.coordinates;
    }
    
    // Repro from #35842
    
    interface SomeObject {
        someProperty: unknown;
    }
    
    let lastSomeProperty: unknown | undefined;
    
    function someFunction(someOptionalObject: SomeObject | undefined): void {
        if (someOptionalObject?.someProperty !== lastSomeProperty) {
            console.log(someOptionalObject);
            console.log(someOptionalObject.someProperty);  // Error
                        ~~~~~~~~~~~~~~~~~~
!!! error TS18048: 'someOptionalObject' is possibly 'undefined'.
            lastSomeProperty = someOptionalObject?.someProperty;
        }
    }
    
    const someObject: SomeObject = {
        someProperty: 42
    };
    
    someFunction(someObject);
    someFunction(undefined);
    
    // Repro from #35970
    
    let i = 0;
    declare const arr: { tag: ("left" | "right") }[];
    
    while (arr[i]?.tag === "left") {
        i += 1;
        if (arr[i]?.tag === "right") {
            console.log("I should ALSO be reachable");
        }
    }