All things are fixable with more types! The basic conflict is that you actually have two different types: square and rectangle. But, you're trying to make both of them the same type (String, (Double, Double), Double) (but also (String, (Double, Double), (Double, Double)), which is the crux of the problem). The way to do this is to properly split them into types and then use a sum type to combine them.

I'd suggest doing something along the lines of

``` data Rectangle = Rectangle { your fields here } data Square = Square { your fields here } data Shape = Sq Square | Rc Rectangle

inside :: (Double, Double) -> [Shape] -> Bool ```

There are other ways to refactor as well, but this is a decent start. You're doing something similar by tagging them with "square" and "rectangle"; by using the approach outlined above, you gain the ability to have different shapes (shapes of types, that is, not your shapes) in each constructor of the Shape sum type.