Doesn't gradual type system mean something else here? As in developers being able to iteratively add types while leaving untyped parts for later? At least this is how Ruby's Sorbet describes it
You’re right about what a gradual type system means! A gradual type system allows flexibility in how you approach typing a codebase. It also means that your system incorporates a dynamic type, making your types 'gradual'.
Interestingly, gradual set-theoretic types are flexible enough to let you gradually implement type inference for that system. Hence, the gradual gradual type system. :-)