Check template contents are valid for root

[MeirionHughes]

given a html container,
when it has a <template> child
then ensure that the template has a template-controller
and ensure contents are valid for the root html container.

example:

<select>
  <template if.bind="foo">
    <template repeat.for="item of items">
       <option ... ></option> <!-- OK -->
       <div ...></div> <!-- INVALID -->
    </template>
  </template>
</select>

should report that <div> is not a valid child of <select>

<select>
  <template> 
     ...
  </template>
</select>

should warn that the template won't be activated in aurelia

[zakjan]

+1

Just a note, if.bind and repeat.for are not allowed on the same element, because their order is undefined. They need to be nested.

[MeirionHughes]

Good point; It'll have to check through nested templates.