[VE][html5] Email Input Attributes

I am using an email input field in my webpage; the code looks like:

<input type="email" id="email" name="email" size="80" maxlength="80" value=""
required="required" />

When I run my page through the W3 HTML5 Validator, I get the following two
errors:

   - Attribute maxlength is only allowed when the input type is e-mail,
   password, search, tel, text, or url.
   - Attribute required is only allowed when the input type is checkbox,
   date, datetime, datetime-local, e-mail, file, month, number, password,
   radio, search, tel, text, time, url, or week.

It's an email input type, but the validator seems to reject it; the
warnings don't seem to make sense.