/a.js(1,16): error TS2322: Type 'boolean' is not assignable to type 'number'.


==== /a.js (1 errors) ====
    function C() { this.x = false; };
                   ~~~~~~
!!! error TS2322: Type 'boolean' is not assignable to type 'number'.
    /** @type {number} */
    C.prototype.x;
    new C().x;
    