Despite its ubiquity, the Linux kernel is not actually the golden standard for safety or performance. Not even for code quality. Ada remains the language of choice in areas where safety is actually crucial. Rust isn't going to take it's spot either.
If any of you reading this comment is interested, you may want to check out my previous comments regarding Ada.[2]
By the way, just to be on topic: I found Linus' opinion on Ada vs Rust here: https://news.ycombinator.com/item?id=20838125. He said "We've had the system people who used Modula-2 or Ada, and I have to say Rust looks a lot better than either of those two disasters.". That is all though, he does not get into explaining why he believes Ada to be a disaster. Again, "I do not see any reasons given for why he considers Ada a disaster. Cannot really do much with this opinion as it is."
[1] Some people claimed that it is a legacy language which is just simply not true. I would suggest that they give https://blog.adacore.com/ and https://blog.adacore.com/gnat-community-2020-is-here a read.
[2]
https://news.ycombinator.com/item?id=19122884 (!)
https://news.ycombinator.com/item?id=19245898 (!!)
https://news.ycombinator.com/item?id=19274244 (!!)
https://news.ycombinator.com/item?id=19274412
https://news.ycombinator.com/item?id=19770405
https://news.ycombinator.com/item?id=20776296
https://news.ycombinator.com/item?id=20934511 (!!) [3]
https://news.ycombinator.com/item?id=20939336 (!!)
https://news.ycombinator.com/item?id=21286061
https://news.ycombinator.com/item?id=21286292
https://news.ycombinator.com/item?id=21435869 (!)
https://news.ycombinator.com/item?id=23609499 (!!)
[3] The last link in that comment returns 404, here is a working one: https://www.ei.tum.de/fileadmin/tueifei/rcs/becker/spark2014...
If there are any other broken links, please, do let me know!
> Standard Ada supports safe use of pointers (“access types” in Ada) via strongtype checking, but safety is guaranteed only for programs where there is no explicit deallocation of pointed-to objects
This validates "With Ada you can't use dynamic memory allocation and pointers safely, unless you buy into SPARK". (GC not relevant in this context.)
> In this work, we propose a restricted form of pointers for Ada that is safe enough to be included in the SPARK subset. As our main contribution, we show how to adapt the ideas underlying the safe pointers from permission-based languages like Rust [3] or ParaSail [13]
This validates that the pointer support in SPARK "post-dates Rust".
"heavier-weight" is arguable. I'll withdraw that assertion. SPARK is definitely less expressive than Rust though; it doesn't have lifetime variables, and it doesn't allow borrows of stack values:
https://blog.adacore.com/using-pointers-in-spark
> The most notable one is that SPARK does not allow general access types. The reason is that we did not want to deal with accesses to variables defined on the stack and accessibility levels.