URL param with type date and default value null breaks

This is a (check one box):

• Bug Report
• Feature Request
• General Query

My version of UI-Router is: (type version)

1.0.27

Bug Report

Current Behavior:

A URL param declaration with type: 'date' and default value: null throws: Cannot read property 'getFullYear' of null

Expected Behavior:

It should work and set null as default value for this param

Link to Plunker or stackblitz that reproduces the issue:

( if you want a response to your issue, provide a way to reproduce it ) ( http://bit.ly/UIR-Plunk1 ) ( https://stackblitz.com/edit/ui-router-angularjs )