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Comment by simonask | Hacker News Reader

So I don’t want to come off as dismissive of the effort - it’s certainly impressive!

The reason I’m not super excited is based on the widely publicized findings from Google and Microsoft (IIRC) about memory safety issues in their code: The vast majority is in new code.

As such, the returns on running the entire userspace with Fil-C may be quite diminished from the get-go. Those who need to guard against UB bugs in seriously battle-hardened C software in production are definitely a small niche.

But that doesn’t mean it isn’t also very useful as a tool during development.

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Hmm, so if they're writing new memory unsafe code in C/C++, presumably to remain within their already established and entrenched C/C++ ecosystems, why isn't Fil-C interesting as a way to thwart memory safety issues in that new code?

Because every problem detected by Fil-C is already a serious problem in the existing code.

As a mitigation strategy, that becomes less interesting as the quality of that code increases, but you still pay the full cost regardless of whether there are actually any bugs.

That can certainly be valuable to you, but as a developer, the more interesting proposition is about how not to ship bugs in the first place.

As others have said, programs that have already been written are plainly not in the business of "not...[shipping] bugs in the first place". New code is new code; old code is old code.

It seems like there are constant updates for 20 year old packages on my Ubuntu systems. Ubuntu 20.04 Focal Fossa (first released April 2020) glibc had an update on 2025-05-28. Current stable updated glibc 2025-09-22. To say nothing about the rest of the packages in that operating system.

Oh, look at the time, a few more CVEs in C code, posted 3 hours ago to Hacker News: "X.Org Security Advisory: multiple security issues X.Org X server and Xwayland"

https://news.ycombinator.com/item?id=45790015

https://lists.x.org/archives/xorg-announce/2025-October/0036...

To torture the analogy: perhaps the "returns" are diminishing, but their absolute value is still a few million bucks, I'm happy to take those returns.

> The reason I’m not super excited is based on the widely publicized findings from Google and Microsoft (IIRC) about memory safety issues in their code: The vast majority is in new code

This makes perfect sense to me.

Which is why I don't at all understand the current fetish with rewriting things that have been working well for decades in Rust. Such as coreutils. Or apt.

It feels like an almost deliberate crippling of progress by diverting top talent into useless avenues, much like string theory in physics, or SLS/Artemis.

> It feels like an almost deliberate crippling of progress by diverting top talent into useless avenues, much like string theory in physics, or SLS/Artemis.

You don't have to be a "top talent" to rewrite old unix utilities. The hard part is writing it safely, which in Rust can be done without "top talent."

And then you end up with code 17 times slower than the C code it is replacing. When it didn't need replacing in the first place.

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