Avoid importing by generating exact names directly

[tfausak]

Fixes #12.

All the types line up, but unfortunately this doesn't work as written. Given a simple module like this:

{-# OPTIONS_GHC -fplugin=Imp #-}

main :: System.IO.IO ()
main = System.IO.print ()

It fails to compile:

Main.hs:3:9: error: [GHC-83249]
    Can't find interface-file declaration for type constructor or class System.IO.IO
      Probable cause: bug in .hi-boot file, or inconsistent .hi file
      Use -ddump-if-trace to get an idea of which file caused the error
  |
3 | main :: System.IO.IO ()
  |         ^^^^^^^^^^^^

Curiously it works fine without the type signature.

[tfausak]

Running with -ddump-if-trace outputs a lot of stuff. Here's the last bit, right before the error:

updating EPS
Considering whether to load GHC.Prim.Ext {- SYSTEM -}
Reading interface for ghc-prim:GHC.Prim.Ext;
    reason: Loading orphan modules (GHC.Prim.Ext)
readIFace /Users/taylor/.ghcup/ghc/9.8.2/lib/ghc-9.8.2/lib/../lib/aarch64-osx-ghc-9.8.2/ghc-prim-0.11.0-f42f/GHC/Prim/Ext.hi
updating EPS
newGlobalBinder Main main Main.hs:6:1-4
                main
Need decl for IO
Considering whether to load System.IO {- SYSTEM -}

[tfausak]

I'm closing this because it's already drifted pretty substantially. Also I'm not sure that this approach is actually any better. I'm sure it's possible to solve the problem I ran into here, but it feels like I'll be recreating import logic by hand in my plugin, which doesn't seem like a good idea.