jsdoc incorrectly validates shorthand arrow functions with nested function signatures

[fracmak]

jsdoc correctly validates simple short hand arrow functions as such:

/** @param {String} xxx */
var funcName = xxx => xxx + 1;

but fails when you add a function signature into the mix

/** @param {String} xxx */
var funcName = xxx => xxx.then(a => a + 1);

with the error message Expected a but got xxx