What is a static or strong type system is sort of up for debate, the terms are not well defined. Not OP, but IMO type annotations are static but not strong. I'd

What is a static or strong type system is sort of up for debate, the terms are not well defined. Not OP, but IMO type annotations are static but not strong. I'd consider a strong type system one that enables you to encode additional invariants in the types, with sum and product types being perhaps the minimal requirement.