Currently, the Input Field only uses its settings to generate an Html 5 input with a specific type and some attributes.
See examples here :
These Html 5 input type and attributes are not supported the same way in all browsers.
I guess you use IE. You should give a try of how it is managed with Chrome, Firefox or Opera.
For example, try your input type=email or type=tel with a regular expression and you should see the warning submitting the form.
The regexp is used to generate the pattern attribute :
What you need to understand is that this is only dependent on the browser for the moment (kind of client side, but not exactly).
The input field needs may be some enhancements to have better client side and server side validation (and add possibility to specify the error message).
As Bertrand said : File a bug.