tests/cases/compiler/narrowingOfDottedNames.ts(45,5): error TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor.
tests/cases/compiler/narrowingOfDottedNames.ts(54,5): error TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor.


==== tests/cases/compiler/narrowingOfDottedNames.ts (2 errors) ====
    // Repro from #8383
    
    class A {
        prop!: { a: string; };
    }
    
    class B {
        prop!: { b: string; }
    }
    
    function isA(x: any): x is A {
        return x instanceof A;
    }
    
    function isB(x: any): x is B {
        return x instanceof B;
    }
    
    function f1(x: A | B) {
        while (true) {
            if (x instanceof A) {
                x.prop.a;
            }
            else if (x instanceof B) {
                x.prop.b;
            }
        }
    }
    
    function f2(x: A | B) {
        while (true) {
            if (isA(x)) {
                x.prop.a;
            }
            else if (isB(x)) {
                x.prop.b;
            }
        }
    }
    
    // Repro from #28100
    
    class Foo1
    {
        x: number;  // Error
        ~
!!! error TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor.
        constructor() {
            if (this instanceof Boolean) {
            }
        }
    }
    
    class Foo2
    {
        x: number;  // Error
        ~
!!! error TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor.
        constructor() {
        }
    }
    
    // Repro from  #29513
    
    class AInfo {
        a_count: number = 1;
    }
    
    class BInfo {
        b_count: number = 1;
    }
    
    class Base {
        id: number = 0;
    }
    
    class A2 extends Base {
        info!: AInfo;
    }
    
    class B2 extends Base {
        info!: BInfo;
    }
    
    let target: Base = null as any;
    
    while (target) {
        if (target instanceof A2) {
            target.info.a_count = 3;
        }
        else if (target instanceof B2) {
            const j: BInfo = target.info;
        }
    }
    