`rustc_layout_scalar_valid_range_start` doesn't prevent `unused_unsafe` lint

[varkor]

Edit: this is just a stage 0 problem, so we can conditionally ignore those warnings for now.

---

rustc_layout_scalar_valid_range_start requires unsafe, but does not cause unsafe blocks to be counted as "used", meaning that the following:

rust/src/libcore/num/mod.rs

Line 71 in 3cda631

Some(unsafe { $Ty(n) })

is warned as unused, but removing the unsafe causes an error.

[varkor]

Another issue is that rustc_layout_scalar_valid_range_start attributes are also considered unused when they are not.

[emilyalbini]

Why is this closed? It's still present (encountered it during beta promotion).

[oli-obk]

Shouldn't beta promotion fix these warnings? stage1 has warnings denied and compiles libcore and libstd just fine.

[emilyalbini]

Not on the beta itself, apparently.

[oli-obk]

That issue is really tracked in #57178