- tcg_inst_uses :: TcRef NameSet,
- -- ^ Home-package Dfuns actually used.
- --
- -- Used to generate version dependencies This records usages, rather
- -- like tcg_dus, but it has to be a mutable variable so it can be
- -- augmented when we look up an instance. These uses of dfuns are
- -- rather like the free variables of the program, but are implicit
- -- instead of explicit.
-
- tcg_th_used :: TcRef Bool,