pass clippy::integer_arithmetic in our shims

[RalfJung]

@oli-obk raised some concerns about this one. I still think it is the right call, since I don't see a good way to enable overflow checks for our official release builds. I'm open to suggestions though!

Fixes #1236

[bors]

☔ The latest upstream changes (presumably #2422) made this pull request unmergeable. Please resolve the merge conflicts.

[oli-obk]

I looked into it and I see no reason why we can't just add debug-assertions=true to the [profile.release] section of our Cargo.toml.

[RalfJung]

We just recently stopped using profiles because they dont work in workspaces - only the profile in the workspace root Cargo.toml is taken into account.

[bors]

☔ The latest upstream changes (presumably #2470) made this pull request unmergeable. Please resolve the merge conflicts.

[oli-obk]

well.. it would mean we at least run with debug assertions if built from within the miri repo, but not when building via x.py. We would then have to tell bootstrap separately to build the miri crate with debug assertions.

[RalfJung]

It also means showing a warning about profiles being ignored on each and every cargo invocation done by x.py. That's not really an option IMO.

[RalfJung]

We would then have to tell bootstrap separately to build the miri crate with debug assertions.

That is the build we ship to users, so it is the most important one here. If that build doesn't end up with overflow checks, we might as well not change anything.

[oli-obk]

.cargo/config.toml to the rescue? Anyway... while I dislike moving to manually checked arithmetic, I do see that it's annoying to ensure we actually generate checked arithmetic, so let's go with this PR for now.

[RalfJung]

.cargo/config.toml to the rescue?

I don't know how to use that to instruct bootstrap to build the Miri crate with overflow checks, but not anything else. Usually flags are the same for an entire workspace, aren't they?

[oli-obk]

Bootstrap will need its own separate logic, but if we had .cargo/config.toml inside this repo, bootstrap would ignore it and only local builds would pick it up

[RalfJung]

Bootstrap will need its own separate logic, but if we had .cargo/config.toml inside this repo, bootstrap would ignore it and only local builds would pick it up

I am not trying to solve a problem with local builds. We can use RUSTFLAGS for that, and anyway CI uses debug builds for ./miri test so we have overflow checks there.

I am trying to solve overflow checks for the build we ship to users.

[RalfJung]

let's go with this PR for now.

Thanks!
@bors r=oli-obk

[bors]

📌 Commit 8497fd4 has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit 8497fd4 with merge 6e306f9...

[RalfJung]

Opened #2501 to track finding a more elegant solution here.

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 6e306f9 to master...