Always use RevealAll for const eval queries

[oli-obk]

implements what is described in #116803 (comment)

Using UserFacing for const eval does not make sense anymore, unless we significantly change things like avoiding revealing opaque types.

New tests are copied from #101478

[rustbot]

r? @b-naber

(rustbot has picked a reviewer for you, use r? to override)

[oli-obk]

@bors try @rust-timer queue

[rustbot]

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

[bors]

⌛ Trying commit e673a9e with merge 488c25a...

[lcnr]

r? @lcnr

[bors]

☀️ Try build successful - checks-actions
Build commit: 488c25a (488c25aafb88817229f076187a7820b2cd70ac6d)

[bors]

☀️ Try build successful - checks-actions
Build commit: 488c25a (488c25aafb88817229f076187a7820b2cd70ac6d)

[rust-timer]

Finished benchmarking commit (488c25a): comparison URL.

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.0%	[3.0%, 3.0%]	1
Improvements ✅ (primary)	-0.2%	[-0.3%, -0.2%]	3
Improvements ✅ (secondary)	-1.4%	[-1.9%, -0.9%]	8
All ❌✅ (primary)	-0.2%	[-0.3%, -0.2%]	3

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.4%, 0.7%]	3
Regressions ❌ (secondary)	1.2%	[1.2%, 1.2%]	1
Improvements ✅ (primary)	-2.6%	[-5.1%, -0.5%]	3
Improvements ✅ (secondary)	-4.6%	[-6.8%, -2.3%]	3
All ❌✅ (primary)	-1.0%	[-5.1%, 0.7%]	6

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	7.7%	[2.1%, 11.7%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 666.26s -> 665.975s (-0.04%)
Artifact size: 308.39 MiB -> 308.41 MiB (0.01%)

[oli-obk]

yay free const eval performance improvement.

[RalfJung]

That comment now probably needs updating?

The assertion error or the comment should explain what a rustc dev should do when they hit this panic.

[RalfJung]

This removes a bunch of code that I never understood and improves performance (except, strangely, in one benchmark). I'm all for it :)

[rustbot]

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

[oli-obk]

fixed test comments

[lcnr]

please update comments and add this test 😁 r=me after that

trait MyTrait: Copy {
    const ASSOC: usize;
}

impl MyTrait for u8 {
    const ASSOC: usize = 32;
}

const fn yeet() -> impl MyTrait {
    0u8
}

const fn output<T: MyTrait>(_: T) -> usize {
    <T as MyTrait>::ASSOC
}

struct Foo<'a>(&'a ())
const NEED_REVEAL_ALL: usize = output(yeet());

fn promote_div() -> &'static usize {
    &(10 / NEED_REVEAL_ALL)
}
fn main() {}

[oli-obk]

@bors r=lcnr

[bors]

📌 Commit 867831a has been approved by lcnr

It is now in the queue for this repository.

[bors]

⌛ Testing commit 867831a with merge 5378c1c...

[bors]

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing 5378c1c to master...

[rust-timer]

Finished benchmarking commit (5378c1c): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.3%, -0.3%]	3
Improvements ✅ (secondary)	-1.4%	[-1.8%, -1.2%]	7
All ❌✅ (primary)	-0.3%	[-0.3%, -0.3%]	3

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	1.5%	[1.5%, 1.5%]	1
Regressions ❌ (secondary)	3.2%	[1.9%, 4.5%]	2
Improvements ✅ (primary)	-4.4%	[-4.4%, -4.4%]	1
Improvements ✅ (secondary)	-1.6%	[-2.4%, -1.2%]	7
All ❌✅ (primary)	-1.4%	[-4.4%, 1.5%]	2

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.6%	[-0.6%, -0.6%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.6%	[-0.6%, -0.6%]	1

Bootstrap: 665.078s -> 663.642s (-0.22%)
Artifact size: 308.34 MiB -> 308.33 MiB (-0.01%)