Properly generalize unevaluated consts

[khyperia]

View all comments

• fixes [ICE]: Unevaluated ty::Const in MIR body #153831
• fixes a // FIXME(ogca) (I am unaware of an issue for this) added in Implement MVP for opaque generic const arguments #150823

r? @BoxyUwU

[rustbot]

changes to the core type system

cc @lcnr

[BoxyUwU]

very cool

View changes since this review

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[BoxyUwU]

looks good to me other than test to add 😌

View changes since this review

[BoxyUwU]

@bors r+ rollup=never

(wouldn't surprise me if it has weird side effects or perf implications or sth)

[rust-bors]

📌 Commit 75eeece has been approved by BoxyUwU

It is now in the queue for this repository.

[rust-bors]

☀️ Test successful - CI
Approved by: BoxyUwU
Duration: 3h 22m 50s
Pushing 37cfa17 to main...

[github-actions]

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 08cd08f (parent) -> 37cfa17 (this PR)

Test differences

Show 4 test diffs

Stage 1

• [ui] tests/ui/const-generics/mgca/free-const-recursive.rs: [missing] -> pass (J0)
• [ui] tests/ui/const-generics/mgca/projection-const-recursive.rs: [missing] -> pass (J0)

Stage 2

• [ui] tests/ui/const-generics/mgca/free-const-recursive.rs: [missing] -> pass (J1)
• [ui] tests/ui/const-generics/mgca/projection-const-recursive.rs: [missing] -> pass (J1)

Job group index

• J0: x86_64-gnu-llvm-21-3, x86_64-gnu-llvm-22-3
• J1: aarch64-apple, aarch64-gnu, aarch64-gnu-llvm-21-1, aarch64-msvc-1, arm-android, armhf-gnu, dist-i586-gnu-i586-i686-musl, i686-gnu-1, i686-gnu-nopt-1, i686-msvc-1, optional-x86_64-gnu-parallel-frontend, test-various, x86_64-gnu, x86_64-gnu-debug, x86_64-gnu-gcc, x86_64-gnu-llvm-21, x86_64-gnu-llvm-21-2, x86_64-gnu-llvm-22-2, x86_64-gnu-nopt, x86_64-gnu-stable, x86_64-mingw-1, x86_64-msvc-1

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 37cfa179be19cec2236736521bed3ea3c4a1ec97 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

1. dist-aarch64-linux: 1h 46m -> 2h 40m (+51.6%)
2. dist-apple-various: 1h 50m -> 1h 23m (-25.0%)
3. aarch64-apple: 3h 5m -> 2h 33m (-17.0%)
4. dist-x86_64-apple: 1h 59m -> 2h 15m (+13.2%)
5. dist-aarch64-msvc: 2h -> 1h 47m (-11.1%)
6. x86_64-gnu: 2h 10m -> 2h 23m (+10.2%)
7. dist-powerpc64-linux-musl: 1h 34m -> 1h 43m (+9.9%)
8. i686-gnu-1: 2h 11m -> 2h 22m (+8.8%)
9. x86_64-gnu-miri: 1h 25m -> 1h 32m (+8.6%)
10. x86_64-mingw-1: 2h 50m -> 2h 36m (-8.2%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

[rust-timer]

Finished benchmarking commit (37cfa17): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Our benchmarks found a performance regression caused by this PR.
This might be an actual regression, but it can also be just noise.

Next Steps:

• If the regression was expected or you think it can be justified,
  please write a comment with sufficient written justification, and add
  @rustbot label: +perf-regression-triaged to it, to mark the regression as triaged.
• If you think that you know of a way to resolve the regression, try to create
  a new PR with a fix for the regression.
• If you do not understand the regression or you think that it is just noise,
  you can ask the @rust-lang/wg-compiler-performance working group for help (members of this group
  were already notified of this PR).

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	3
Improvements ✅ (primary)	-0.3%	[-0.3%, -0.3%]	1
Improvements ✅ (secondary)	-0.1%	[-0.2%, -0.0%]	7
All ❌✅ (primary)	-0.3%	[-0.3%, -0.3%]	1

Max RSS (memory usage)

Results (primary 1.7%, secondary -0.9%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.7%	[1.7%, 1.7%]	1
Regressions ❌ (secondary)	2.9%	[2.9%, 2.9%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.7%	[-4.7%, -4.7%]	1
All ❌✅ (primary)	1.7%	[1.7%, 1.7%]	1

Cycles

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

Binary size

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

Bootstrap: 484.85s -> 485.095s (0.05%)
Artifact size: 394.86 MiB -> 394.90 MiB (0.01%)