@ngdoc error
@name $compile:tplrt
@fullName Invalid Template Root
@description

When a directive is declared with `template` (or `templateUrl`) and `replace` mode on, the template
must have exactly one root element. That is, the text of the template property or the content
referenced by the templateUrl must be contained within a single html element.
For example, `<p>blah <em>blah</em> blah</p>` instead of simply `blah <em>blah</em> blah`.
Otherwise, the replacement operation would result in a single element (the directive) being replaced
with multiple elements or nodes, which is unsupported and not commonly needed in practice.


For example a directive with definition:

```
myModule.directive('myDirective', function factory() {
  return {
    ...
    replace: true,
    templateUrl: 'someUrl'
    ...
  }
});
```

And a template provided at URL `someUrl`. The template must be an html fragment that has only a
single root element, like the `div` element in this template:

```
<div><b>Hello</b> World!</div>
```

An invalid template to be used with this directive is one that defines multiple root nodes or
elements. For example:

```
<b>Hello</b> World!
```

Watch out for html comments at the beginning or end of templates, as these can cause this error as
well.  Consider the following template:

```
<div class='container'>
  <div class='wrapper'>
     ...
  </div> <!-- wrapper -->
</div> <!-- container -->
```

The `<!-- container -->` comment is interpreted as a second root element and causes the template to
be invalid.
