string mixin only works once per block?

[Vlad Levenfeld]

actually I just realized there is a bug, in the 2nd case of 
collect_fields:

else static if (members[0] == "this")
   return [];

Should be:

else static if (members[0] == "this")
   return collect_fields!(T, attribute, members[1..$]);

Otherwise the method craps out on the constructor and returns an 
incomplete list.