Rice's theorem only aplies to turing complete programs, so if youre "weak enough" there's no problem being both sound and complete. I think it's easy to see why people would think of such systems as "nicer" (even though the others are of course still rigorous).
>It's true that type inference becomes undecidable without annotations for things like dependent types, and there's nothing hacky about that.
But it's not just for more advanced type systems, type inference is undecidable for basically any system more complex than HM typing. So in practice virtually all programming languages with type systems that go beyond the absolue basics can't fullfill the "promise" of type inference, which is that you don't have to explicitly annotate types. I think if you take into consideration that even relatively "good" type systems like Haskell's occasionally require you to annotate not just functions, but 'random' terms, you might see why some people might consider it "hacky".
>It's true that type inference becomes undecidable without annotations for things like dependent types, and there's nothing hacky about that.
But it's not just for more advanced type systems, type inference is undecidable for basically any system more complex than HM typing. So in practice virtually all programming languages with type systems that go beyond the absolue basics can't fullfill the "promise" of type inference, which is that you don't have to explicitly annotate types. I think if you take into consideration that even relatively "good" type systems like Haskell's occasionally require you to annotate not just functions, but 'random' terms, you might see why some people might consider it "hacky".