I personally don't think I would want to use a language that doesnt have a borrow checker ever again. I would like a Rust-like language with GC, but I still wan

I personally don't think I would want to use a language that doesnt have a borrow checker ever again. I would like a Rust-like language with GC, but I still want the borrow checker. Every time I write Go, I find it so annoying all the defensive deep copying I see. In JS I always find myself getting confused on whether a mutation is safe (as in my program won't break some assumption) to do or not. Marking arguments as shared or exclusive is really great for me to know what kind of access I can have. It needs to be enforced so that the owner also doesn't accidentally mutate while a shared borrow is still active (again, not just for memory safety but for my own invariants). The classic example could be inserting into a collection while iterating over it I think the borrow checker is necessary if you have ADTs like Rust and you want memory safety. You could pattern match a union into one of its variants and get a pointer to one of the fields, but without a borrow checker there's nothing to stop you from changing the variant stored in the union. This would obviously cause issues and the only way you'd solve this with GC alone is by allocating each variant individually where the union is just a tagged pointer.