Haskell: Is It Possible to Add a Type Annotation?

The type system in Haskell is missing a powerful meta programming type system. You can blow up the type system by just generating variables. It reminds me, I don't know if this is true that when they added type classes to Haskell, they went a little bit overboard and they defined like type classes for like addition, for example. And then it turned out that because of type classes,I guess it makes sense that it makes it harder for it to solve Because it can be anything that implements this type class.