Indentation and table start only recognized at start of line

[mhsmith]

MediaWiki renders the following as an indented table:

:{|
|-
|rowspan=5 valign=top|1 astronomical unit  
|= {{val|149597870700}} [[metre]]s (exactly)
|-
|≈ {{val|92.955807}} million [[mile]]s
|}

But mwparserfromhell doesn't recognize it as a table at all:

<
      dd
/>
{|\n|-\n|rowspan=5 valign=top|1 astronomical unit
&nbsp;
\n|=
{{
      val
    | 1
    = 149597870700
}}

[[
      metre
]]
s (exactly)\n|-\n|\u2248
...

If you put a comment on the same line immediately before the indentation:

<!-- -->:{|

then the indentation doesn't get parsed either.