Things Zig comptime won't do

I like the Zig language and tooling. I do wish there was a safety mode that give the same guarantees as Rust, but it’s a huge step above C/C++. I am also extremely impressed with the Zig compiler.

Perhaps the safety is the tradeoff with the comparative ease of using the language compared to Rust, but I’d love the best of both worlds if it were possible

>but I’d love the best of both worlds if it were possible

I am just going to quote what pcwalton said the other day that perhaps answer your question.

>> I’d be much more excited about that promise [memory safety in Rust] if the compiler provided that safety, rather than asking the programmer to do an extraordinary amount of extra work to conform to syntactically enforced safety rules. Put the complexity in the compiler, dudes.

> That exists; it's called garbage collection.

>If you don't want the performance characteristics of garbage collection, something has to give. Either you sacrifice memory safety or you accept a more restrictive paradigm than GC'd languages give you. For some reason, programming language enthusiasts think that if you think really hard, every issue has some solution out there without any drawbacks at all just waiting to be found. But in fact, creating a system that has zero runtime overhead and unlimited aliasing with a mutable heap is as impossible as finding two even numbers whose sum is odd.

[1] https://news.ycombinator.com/item?id=43726315

Maybe this is a bad place to ask, but: Those experienced in manual-memory langs: What in particular do you find cumbersome about the borrow system? I've hit some annoyances like when splitting up struct fields into params where more than one is mutable, but that's the only friction point that comes to mind.

I ask because I am obvious blind to other cases - that's what I'm curious about! I generally find the &s to be a net help even without mem safety ... They make it easier to reason about structure, and when things mutate.

Lifetime annotations can be burdensome when trying to avoid extraneous copies and they feel contagious (when you add a lifetime annotation to a frequently used type, it bubbles out to anything that uses that type unless you're willing to use unsafe to extend lifetimes). The solutions to this problem (tracking indices instead of references) lose a lot of benefits that the borrow checker provides.

The aliasing rules in Rust are also pretty strict. There are plenty of single-threaded programs where I want to be able to occasionally read a piece of information through an immutable reference, but that information can be modified by a different piece of code. This usually indicates a design issue in your program but sometimes you just want to throw together some code to solve an immediate problem. The extra friction from the borrow checker makes it less attractive to use Rust for these kinds of programs.