Better error messages for broken HTML tag hierarchy

[tomasherceg]

Consider this piece of code:

<ItemTemplate>
    <tr>
        <td>cell with invalid end tag</th>
    </tr>
</ItemTemplate>

DotVVM reports error that the </ItemTemplate> doesn't have its open tag.

It is not a high priority issue to work on, however it is not very intuitive.

[exyi]

We should not only fix this issue, but improve entire error reporting from compilation. We should add strict mode, that would fail on warnings ( #101 ) and improve the error page to display all compilation errors and warnings on the page, not just the first one.

[Mylan719]

The compiler is a bit stupid about reporting errors on unclosed tags. There is simple mechanism, that reports it correctly for most cases but that part would have to be rewritten to account for every case. Also it is bit messy from the time it was still a proof of concept.