Worth noting that Zig has ReleaseSafe, which safety-checks undefined behavior while applying any optimizations it can given that restriction. The more interest

Worth noting that Zig has ReleaseSafe, which safety-checks undefined behavior while applying any optimizations it can given that restriction. The more interesting part is that the mode can be individually modified on a per-block basis with the @setRuntimeSafety builtin, so it's practical to identify the performance-critical parts of the program and turn off safety checks only for them. Or the opposite: identify tricky code which is doing something complex, and turn on runtime safety there, regardless of the build status. That's why this sort of thing should be part of the specification. @setRuntimeSafety would be meaningless without the concept of safety-checked undefined behavior. I would say that making optionals and fat pointers (slices) a part of the type system is possibly more important, but it all combines to give a fighting chance of getting user-controlled resource management correct. Given the topic of the Fine Article, it's worth briefly noting that `defer` and `errdefer` are keywords in Zig. Both the test allocator, and the GeneralPurposeAllocator in safe mode, will panic if you leak memory by forgetting to use these, or rather, forget to free allocations generally. My impression is that the only major category of memory bugs these tools won't catch in development is double-free, and that's being worked on.