optimize' :: Opti [Name]
optimize' = do
  main <- findDecl "main"
  case main of
    Just expr -> mread expr
    Nothing -> throwOE "Can't optimize, no 'main' found"
optimize' :: Opti [Name]
optimize' = do
  main <- findDecl "main"
  case main of
    Just expr -> mread expr
    Nothing -> throwOE "Can't optimize, no 'main' found"
optimize' = do
  main <- findDecl "main"
  case main of
    Just expr -> mread expr
    Nothing -> throwOE "Can't optimize, no 'main' found"