link_to doesn't work when any link_to's are inside HTML

[Klondike]

This one is weird. This works as expected:

Web.popup do
  title "Choose a file to download:"
  link_to "Quit"
end

And so does this:

Web.popup do
  title "Choose a file to download:"
  link_to "Quit"
  table.each do |file|
    tag! "br"
    link_to file[:filename]
  end
end

But this does *not*:

Web.popup do
  title "Choose a file to download:"
  link_to "Quit"
  table.each do |file|
    p do
      link_to file[:filename]
    end
  end
end

In fact, doing that means even the "Quit" link_to doesn't work! The return value of this block is always nil.