On Wed, Apr 14, 2021 at 9:19 PM Linus Torvalds
[off-list ref] wrote:

Not being a Rust person, I can only guess based on random pattern
matching, but this _looks_ like these "panicking intrinsics" panic at
run-time (by calling BUG()).

Your pattern matching works well :)

Is there some way these things could cause built-time link errors
instead, so that if somebody uses 128-bit shifts, or floating point
ops in the rust code, they show up as build failures, not as run-time
ones?

Yes, we should definitely make this a compile-time error if possible!
This was the easy way out for the moment.

In general, there are some things that are currently unneeded from the
Rust standard library. When we get to remove those, many of those
intrinsics should go away, and then we can leave it as a link error.

Cheers,
Miguel