[project @ 2000-11-20 14:48:52 by simonpj]
When renaming, typechecking an expression from the user interface, we may suck in declarations from interface files (e.g. the Prelude). This commit takes account of that. To do so, I did some significant restructuring in TcModule, with consequential changes and tidy ups elsewhere in the type checker. I think there should be fewer lines in total than before.