That's completely worthless. C is also memory-safe if you stay within the rules for memory safety.
> Nim is not throwing around vague claims of safety that are not documented in the language manual.
Of course not since nim is not posting on HN (as it's not a sentient being prone to procrastination) it's obviously nim supporters making claims about nim's safety.
It's really not any weaker of a guarantee than Rust makes, being memory-safe if you stay within the rules of not saying `unsafe`. Or opening /proc/self/mem for writing, anyway.
I'd also feel a lot better about Rust's moral highground of memory safety if its undefined behavior was actually spelled out a bit more rather than just punting the hard parts to llvm docs. I don't think every Rust user knows how to avoid aliasing problems between `&mut` and `*mut` either.
That said, I don't agree with the claim that Nim is less safe than Rust because Nim uses "ptr" types and Rust uses "unsafe" blocks to mark unsafe regions. I prefer Rust's approach, but it's pretty much just a question of UI, not anything substantive.