Great improvements! Congrats on the release. I don't like the ergonomics of `mutable struct` vs (immutable) `struct`. Adding `const` seems like another step in

Great improvements! Congrats on the release. I don't like the ergonomics of `mutable struct` vs (immutable) `struct`. Adding `const` seems like another step in the wrong direction. Right now, there's `struct` + `Ref{T}` fields for having a immutable struct with fields that can be mutated VS `mutable struct` + `const` fields for a mutable struct with fields that can't be mutated. And defining mutability at the `struct` level is kind of painful. Sometimes I want to accept user input in a type checked manner (i.e. not storing them in dictionaries and using typed struct fields) and then pass that struct into a core algorithm where execution needs to be fast (i.e. aligned memory, immutable structs etc). Rust does this by making the mutability declared at an individual function level or during access to the struct value. In Julia, I have to decide ahead of time and that changes how users would use a library of mine. I also dislike that syntax `a.b += 1` is not allowed for fields in immutable structs. I would love it if `@immutable_mutate a.b += 1` de-sugared to `a = A(b = a.b + 1, a...)` or the equivalent. If this existed I think I would just use immutable structs ALL the time. If a macro for that existed in Base Julia that would be amazing. (I don't want to use third party libraries for this.) I'm (cautiously?) optimistic that Julia will be absolutely awesome in like 5 years. Currently, 90% of my work in Julia is painful because of poor developer workflow / tools. But when I need to do the remaining 10% (performance / optimization of code), Julia is amazing. Right now, it is probably easier to write code in Python (with type hints) and drop down to Rust or Go whenever performance is needed, than to start with Julia in the first place.