// @target: es2015
// @allowJs: true
// @checkJs: true
// @outDir: ./out
// @filename: assertionTypePredicates2.js

/**
 * @typedef {{ x: number }} A
 */

/**
 * @typedef { A & { y: number } } B
 */

/**
 * @param {A} a
 * @returns { asserts a is B }
 */
const foo = (a) => {
    if (/** @type { B } */ (a).y !== 0) throw TypeError();
    return undefined;
};

export const main = () => {
    /** @type { A } */
    const a = { x: 1 };
    foo(a);
};
