[DO NOT MERGE] bootstrap with `-Znext-solver=globally` #133502

lcnr · 2024-11-26T15:26:47Z

A revival of #124812. See

Current status:

~~./x.py b --stage 2 passes 🎉~~

try builds succeed 🎉 🎉 🎉

first perf run 👻 second perf run 👻 third perf run 👻

crater

This does not detect hangs or memory issues.

date	#crates	#regressions
2025.04.11	100	2
2025.04.11	1000	27
2025.04.17	10000	456
2025.04.18	10000	437
2025.04.24	10000	164
2025.04.26	10000	108
2025.04.28	10000	91
2025.05.01	10000	145 woops
2025.05.03	624228¹	1585²
2025.05.05	8964³	931²
2025.05.06	4401³	726²
2025.05.07	2704³	668²
2025.05.09	2345³	664²
2025.09.20	701952¹	4739 + 7039 spurious
2025.10.02	11712³	2568 + 2014 spurious
2025.10.04	4582³	1173 + 1147 spurious²

in-flight changes

r? @ghost

a complete crater run ↩ ↩²
with doubled recursion_limit when evaluating goals ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
only testing crates which may have regressed from the above run ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

compiler-errors · 2024-11-27T04:03:51Z

@bors try

[DO NOT MERGE] bootstrap with `-Znext-solver=globally` A revival of rust-lang#124812. Current status, we're failing in: - failing in `rustc_next_trait_solver` with 126 instances of the following error ``` error[E0311]: the parameter type `I` may not live long enough | help: consider adding an explicit lifetime bound --> compiler/rustc_next_trait_solver/src/solve/trait_goals.rs:624:53 | 624 ~ fn consider_structural_builtin_unsize_candidates<'a>( 625 ~ ecx: &mut EvalCtxt<'a, D>, 626 | goal: Goal<I, Self>, 627 ~ ) -> Vec<Candidate<I>> where I: 'a { ``` - `itertools` hangs, we're already encountered this hang in our previous attempt due to large type sizes. I believe that it's simply caused by a missing cache somewhere, potentially in `wf.rs`, but other visitors may also be responsible. See rust-itertools/itertools#945 for more details ### commits - rust-lang#133501 - rust-lang#133493 - 9456bfe and b21b116 reimplement candidate preference based on rust-lang#132325, not yet a separate PR - c3ef9cd is a rebased version of rust-lang#125334, unsure whether I actually want to land this PR for now r? `@ghost`

bors · 2024-11-27T04:05:03Z

⌛ Trying commit f631ca8 with merge ca04381...

compiler-errors · 2024-11-27T04:05:17Z

I also pushed:

I think this is sufficient to make the compiler build, or at least ./x.py build --stage=2 completes successfully on my local branch.

bors · 2024-11-27T06:15:40Z

💔 Test failed - checks-actions

bors · 2024-11-27T10:43:04Z

☔ The latest upstream changes (presumably #133527) made this pull request unmergeable. Please resolve the merge conflicts.

lqd · 2024-11-27T11:42:49Z

Next failure is on color-print-proc-macro-0.3.6 while building cargo.

pub fn repro() -> impl FnMut() {
    if true {
        || ()
    } else {
        || ()
    }
}

godbolt

compiler-errors · 2024-11-27T17:49:50Z

@bors try

[DO NOT MERGE] bootstrap with `-Znext-solver=globally` A revival of rust-lang#124812. Current status: `./x.py b --stage 2` passes 🎉 ### commits - rust-lang#133501 - rust-lang#133493 - 9456bfe and b21b116 reimplement candidate preference based on rust-lang#132325, not yet a separate PR - c3ef9cd is a rebased version of rust-lang#125334, unsure whether I actually want to land this PR for now - rust-lang#133517 * rust-lang#133518 * rust-lang#133519 * rust-lang#133520 * rust-lang#133521 * rust-lang#133524 r? `@ghost`

bors · 2024-11-27T17:51:02Z

⌛ Trying commit 6210ed3 with merge ac5ccad...

bors · 2024-11-27T20:03:42Z

💔 Test failed - checks-actions

compiler-errors · 2024-11-27T20:15:22Z

@bors try

[DO NOT MERGE] bootstrap with `-Znext-solver=globally` A revival of rust-lang#124812. Current status: `./x.py b --stage 2` passes 🎉 ### commits - rust-lang#133501 - rust-lang#133493 - 9456bfe and b21b116 reimplement candidate preference based on rust-lang#132325, not yet a separate PR - c3ef9cd is a rebased version of rust-lang#125334, unsure whether I actually want to land this PR for now - rust-lang#133517 * rust-lang#133518 * rust-lang#133519 * rust-lang#133520 * rust-lang#133521 * rust-lang#133524 r? `@ghost`

bors · 2024-11-27T20:16:33Z

⌛ Trying commit 8fa8f40 with merge 550ae0d...

lqd · 2024-11-27T20:26:10Z

I was reducing the new failure but you've already fixed it ^^

craterbot · 2025-10-04T02:33:54Z

🚧 Experiment pr-133502-16 is now running

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2025-10-04T04:57:09Z

🎉 Experiment pr-133502-16 is completed!
📊 1173 regressed and 0 fixed (4582 total)
📊 1147 spurious results on the retry-regessed-list.txt, consider a retry¹ if this is a significant amount.
📰 Open the summary report.

⚠️ If you notice any spurious failure please add them to the denylist!
ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

re-run the experiment with crates=https://crater-reports.s3.amazonaws.com/pr-133502-16/retry-regressed-list.txt ↩

we should not get the certainty from the current result of the provisional cache entry

…pre-fallback where we equate hidden types but do not report errors

lcnr · 2025-10-07T19:47:41Z

@bors try @rust-timer queue

[DO NOT MERGE] bootstrap with `-Znext-solver=globally`

rust-log-analyzer · 2025-10-07T20:19:21Z

The job aarch64-gnu-llvm-20-2 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

failures:

---- tests::test_unstable_options_tracking_hash stdout ----

thread 'tests::test_unstable_options_tracking_hash' (49967) panicked at compiler/rustc_interface/src/tests.rs:833:5:
assertion `left != right` failed
  left: NextSolverConfig { coherence: true, globally: true }
 right: NextSolverConfig { coherence: true, globally: true }
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed::<rustc_session::config::NextSolverConfig, rustc_session::config::NextSolverConfig>

rust-bors · 2025-10-07T22:07:42Z

☀️ Try build successful (CI)
Build commit: d58c646 (d58c64674341fa7eaac5e571c8d5b45efd427811, parent: fed46ffd5059e11669df1bd9406b02914c3fb73f)

rust-timer · 2025-10-07T23:48:01Z

Finished benchmarking commit (d58c646): comparison URL.

Overall result: ❌✅ regressions and improvements - BENCHMARK(S) FAILED

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

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

❗ ❗ ❗ ❗ ❗
Warning ⚠️: The following benchmark(s) failed to build:

issue-46449
unify-linearly
clap_derive-4.5.32
nalgebra-0.33.0
stm32f4-0.15.1
diesel-2.2.10
issue-58319
unicode-normalization-0.1.24
regression-31157
match-stress
html5ever-0.31.0
hyper-1.6.0
eza-0.21.2
ucd
ripgrep-14.1.1
serde-1.0.219-threads4
issue-88862
serde-1.0.219
image-0.25.6
derive
typenum-1.18.0
many-assoc-items
regex-automata-0.4.8
bitmaps-3.2.1
wg-grammar
cargo-0.87.1
cranelift-codegen-0.119.0
libc-0.2.172
serde_derive-1.0.219
syn-2.0.101

❗ ❗ ❗ ❗ ❗

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)	20.6%	[0.1%, 473.7%]	167
Regressions ❌ (secondary)	73.9%	[0.1%, 2392.2%]	167
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.7%	[-26.9%, -0.1%]	53
All ❌✅ (primary)	20.6%	[0.1%, 473.7%]	167

Max RSS (memory usage)

Results (primary 6.8%, secondary 11.1%)

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

	mean	range	count
Regressions ❌ (primary)	7.1%	[0.9%, 37.7%]	98
Regressions ❌ (secondary)	19.9%	[1.6%, 97.6%]	32
Improvements ✅ (primary)	-4.8%	[-7.4%, -1.9%]	3
Improvements ✅ (secondary)	-3.1%	[-6.4%, -0.8%]	20
All ❌✅ (primary)	6.8%	[-7.4%, 37.7%]	101

Cycles

Results (primary 21.5%, secondary 97.2%)

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

	mean	range	count
Regressions ❌ (primary)	21.5%	[2.2%, 382.6%]	120
Regressions ❌ (secondary)	109.3%	[1.8%, 2304.5%]	101
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-14.2%	[-31.6%, -2.5%]	11
All ❌✅ (primary)	21.5%	[2.2%, 382.6%]	120

Binary size

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

Bootstrap: 474.165s -> 524.032s (10.52%)
Artifact size: 388.38 MiB -> 386.86 MiB (-0.39%)

lcnr · 2025-10-09T08:55:36Z

@bors try

[DO NOT MERGE] bootstrap with `-Znext-solver=globally` try-job: x86_64-fuchsia

rust-bors · 2025-10-09T08:56:26Z

💔 Test for 62810ce failed: CI. Failed job:

Calculate job matrix (web logs, extended logs)

rust-log-analyzer · 2025-10-09T08:56:30Z

A job failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

   Compiling ureq v3.0.8
   Compiling citool v0.1.0 (/home/runner/work/rust/rust/src/ci/citool)
    Finished `dev` profile [unoptimized] target(s) in 18.77s
     Running `target/debug/citool calculate-job-matrix`
Run type: TryJob { job_patterns: Some(["x86_64-fuchsia"]) }
Error: Failed to calculate job matrix

Caused by:
    Patterns `x86_64-fuchsia` did not match any auto jobs
##[error]Process completed with exit code 1.
Post job cleanup.

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) labels Nov 26, 2024

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compiler-errors force-pushed the rust4 branch from c3ef9cd to f631ca8 Compare November 27, 2024 04:03

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bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Nov 27, 2024

compiler-errors force-pushed the rust4 branch from f631ca8 to 6210ed3 Compare November 27, 2024 17:49

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compiler-errors force-pushed the rust4 branch from 6210ed3 to 8fa8f40 Compare November 27, 2024 20:15

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craterbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-crater Status: Waiting on a crater run to be completed. labels Oct 4, 2025

lcnr and others added 10 commits October 7, 2025 21:41

check for empty heads after adding parent

d7664f5

fix RebaseReason::Ambiguity

ed6a7b1

we should not get the certainty from the current result of the provisional cache entry

obligations_for_self_ty: skip irrelevant goals

55c85b1

also filter obligations by sub_root

b33a98e

instantiate predicate binder without recanonicalizing goal in new solver

fc7d24d

-Znext-solver: slightly strenghten closure sig inference

3090ca8

When computing opaque types in the next solver, take an initial pass …

547aa97

…pre-fallback where we equate hidden types but do not report errors

enable -Znext-solver by default

91d5282

w

2f32e3b

double recursion limit for next-solver

89b6176

lcnr force-pushed the rust4 branch from e3b862a to 89b6176 Compare October 7, 2025 19:42

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rust-bors bot added a commit that referenced this pull request Oct 7, 2025

Auto merge of #133502 - lcnr:rust4, r=<try>

d58c646

[DO NOT MERGE] bootstrap with `-Znext-solver=globally`

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Oct 7, 2025

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rust-bors bot added a commit that referenced this pull request Oct 9, 2025

Auto merge of #133502 - lcnr:rust4, r=<try>

62810ce

[DO NOT MERGE] bootstrap with `-Znext-solver=globally` try-job: x86_64-fuchsia

[DO NOT MERGE] bootstrap with -Znext-solver=globally #133502

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[DO NOT MERGE] bootstrap with -Znext-solver=globally #133502

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Overall result: ❌✅ regressions and improvements - BENCHMARK(S) FAILED

Instruction count

Max RSS (memory usage)

Cycles

Binary size

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[DO NOT MERGE] bootstrap with `-Znext-solver=globally` #133502

[DO NOT MERGE] bootstrap with `-Znext-solver=globally` #133502

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