JsDoc inline function signature does not honor optional params

[billti]

The below two should be equivalent, however the optionality is lost of the second param on f6.

/** @type {function(string, boolean=): number} */
var f6;

/**
 * @param {string} p1
 * @param {boolean=} p2
 * @return {number}
 */
function f7(p1,p2){}