+ linkableUnlinked :: [Unlinked]
+ -- ^ Those files and chunks of code we have yet to link.
+ --
+ -- INVARIANT: A valid linkable always has at least one 'Unlinked' item.
+ -- If this list is empty, the Linkable represents a fake linkable, which
+ -- is generated in HscNothing mode to avoid recompiling modules.
+ --
+ -- XXX: Do items get removed from this list when they get linked?