I've seen Go codebases where serialization was used as a way to generics... ugly.

The generic code would take a string of the serialized struct, which could be passed through (the code was operating on an outer structure) then be deserialized at the other end, preserving the type information. Maybe it could have been handled by some kind of typecasting plus an enum containing the name of the type (don't remember the specifics of Go right now), but the devs had halfway convinced themselves that the serialization served another purpose.

lean4 unifies types and values, so that types feels so natural. you stop thinking types at all as you think about types in rust or csharp. and haskell does not have that feeling too.

zig may be like that too, but not tried.

Yes. It might sound counter-intuitive or even ironical but the next logical step is to make the type system more, not less expressive and to add completely dependent types. Every language already has them to the extent of Array<T, N> (or T[] & { length: N }, or a recursively defined Tuple<T, N>), but having true flow- and value-dependent types would allow for more concise and expressive code.

Lately I’ve been exploring zig and outside of painfully underdeveloped documentation I haven’t had so much fun with types (of comptime) for the long time.

I find it much more ergonomic than Rust and less energy draining than OCaml.

Then there’s pattern matching, but IMO Elixir is heading in the wrong direction. Erlang has accumulated dust over the decades. Clojure is very interesting choice because it can do both „comptime” (i.e. macros) and pattern matching.

Elm's a great example of a language that's fully statically typed, but where the language doesn't result in long complex types.

In my mind Rust is one of the nicest, most ergonomic type systems. People say it's highly complex, but I think that's really because its type system also includes reference and lifetime annotation.

As a culture, I think Rust developers do a great job of designing well for a simpler type signature.

Gleam is great too!