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Comment by teiferer | Hacker News Reader

> In my experience, the more information is encoded in the type system, the more effort is required to change code.

I would tend to disagree. All that information encoded in the type system makes explicit what is needed in any case and is otherwise only carried informally in peoples' heads by convention. Maybe in some poorly updated doc or code comment where nobody finds it. Making it explicit and compiler-enforced is a good thing. It might feel like a burden at first, but you're otherwise just closing your eyes and ignoring what can end up important. Changed assumptions are immediately visible. Formal verification just pushes the boundary of that.

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In practice it would be encoded in comments, automated tests and docs, with varying levels of success.

It’s actually similar to tests in a way: they provide additional confidence in the code, but at the same time ossify it and make some changes potentially more difficult. Interestingly, they also make some changes easier, as long as not too many types/tests have to be adapted.

This reads to me like an argument for better refactoring tools, not necessarily for looser type systems. Those tools could range from mass editing tools, IDEs changing signatures in definitions when changing the callers and vice versa, to compiler modes where the language rules are relaxed.

I was thinking about C++ and if you change your mind about whether some member function or parameter should be const, it can be quite the pain to manually refactor. And good refactoring tools can make this go away. Maybe they already have, I haven’t programmed C++ for several years.

Constraints Liberate, Liberties Constrain. (I also recommend watching the presentation with the same title)

> All that information encoded in the type system makes explicit what is needed in any case and is otherwise only carried informally in peoples' heads by convention

this is, in fact better for llms, they are better at carrying information and convention in their kv cache than they are in having to figure out the actual types by jumping between files and burning tokens in context/risking losing it on compaction (or getting it wrong and having to do a compilation cycle).

if a typed language lets a developer fearlessly build a semantically inconsistent or confusing private API, then llms will perform poorer at them even though correctness is more guaranteed.

It is definitely harder to refactor Haskell than it is Typescript. Both are "safe" but one is slightly safer, and much harder to work with.

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