std.xml should just go

[so]

> What would you do in the case of pointers to functions, virtual  
> functions, functions implemented with inline assembly, and functions for  
> which the source is not available?

Just like we don't know if the derived class overrides a given function,  
we could do something similar i suppose?
Similar could be applied to functions without source, after all we don't  
know until linking that the provided function has the right signature. I  
am sorry if these doesn't make sense for a compiler writer, i have no idea  
about the process :)