gistfile1.txt

Generate arbitrary modifier (using Arb/CoArb), e.g. a
  (Set HaskellFilePath -> Vec (NModsPerRound :: Nat) (HaskellFilePathToModify,Modification))

  newtype Modification = (UniqueNameForStats, DescrText, Qualifier, HaskellText -> HaskellText)
  type Qualifier -- info such as: Is this an internal module

  instance Arbitrary
  -- Some clever thing here
  -- E.g.
  -- ("Remove Nth (wrapping around) import line",...)
  
Other ideas:
  Remove Nth language extension (internal modules only)
  Remove Nth (wrapping around) explicit import list entry (in file...)
  Turn Nth "everything" import into instance only, e.g. "import A()"
      Or even, import A(xs...) where xs is an arbitrary subset of unqual identifiers in the file (not imported from elsewhere)
   
  Remove N-th top-level definition (internal modules only)
  Remove N-th entry from export list (internal modules only)
  Add complete export list when none exists (always safe)
  
  Remove dep from Cabal file