toScalExp look (BasicOp (BinOp (Sub t) (Constant x) y))
  | typeIsOK $ IntType t, zeroIsh x =
  Just . SNeg <$> subExpToScalExp' look y
toScalExp look (BasicOp (BinOp (Sub t) (Constant x) y))
  | typeIsOK $ IntType t, zeroIsh x =
  Just . SNeg <$> subExpToScalExp' look y
toScalExp look (BasicOp (BinOp (Sub t) (Constant x) y))
  | typeIsOK $ IntType t, zeroIsh x =
  Just . SNeg <$> subExpToScalExp' look y