remove sub_relations from the InferCtxt

[lcnr]

While doing so, I tried to remove the delay_span_bug in rematch_impl again, which lead me to discover another freshen bug, fixing that one in the second commit. See commit descriptions for the reasoning behind each change.

r? @compiler-errors

[rustbot]

Type relation code was changed

cc @compiler-errors, @lcnr

[lcnr]

@bors try @rust-timer queue

[bors]

⌛ Trying commit d99a07d with merge 5d00403...

[lcnr]

Suggested change

	// We need to use a separate variable here as we otherwise the temporary for
	// We need to use a separate variable here as otherwise the temporary for

[bors]

☀️ Try build successful - checks-actions
Build commit: 5d00403 (5d004039df46bb665b8ed6385386e3b1b007a6a8)

[rustbot]

Some changes occurred to the core trait solver

cc @rust-lang/initiative-trait-system-refactor

[lcnr]

we could even change this to always emit "cyclic type of infinite size", even though that isn't completely correct as the subtype obligation could simply be unfortunate and the actual overflow cause is something else 🤷 don't have a strong opinion here

[rust-timer]

Finished benchmarking commit (5d00403): comparison URL.

Overall result: ✅ improvements - no 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.

@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)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.4%, -0.2%]	20
Improvements ✅ (secondary)	-0.4%	[-0.6%, -0.2%]	19
All ❌✅ (primary)	-0.2%	[-0.4%, -0.2%]	20

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
Regressions ❌ (secondary)	1.6%	[0.8%, 2.4%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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: 669.714s -> 667.26s (-0.37%)
Artifact size: 308.18 MiB -> 308.20 MiB (0.01%)

[lcnr]

@craterbot check

[craterbot]

👌 Experiment pr-119989 created and queued.
🤖 Automatically detected try build 5d00403
⚠️ Try build based on commit d99a07d, but latest commit is 344cd47. Did you forget to make a new try build?
🔍 You can check out the queue and this experiment's details.

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

[craterbot]

🚧 Experiment pr-119989 is now running

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

[bors]

☔ The latest upstream changes (presumably #120089) made this pull request unmergeable. Please resolve the merge conflicts.

[craterbot]

🎉 Experiment pr-119989 is completed!
📊 53 regressed and 5 fixed (408433 total)
📰 Open the full report.

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

[compiler-errors]

r=me when green

[lcnr]

@bors r=compiler-errors rollup=never

[bors]

📌 Commit c71484e has been approved by compiler-errors

It is now in the queue for this repository.

[bors]

⌛ Testing commit c71484e with merge 397937d...

[bors]

☀️ Test successful - checks-actions
Approved by: compiler-errors
Pushing 397937d to master...

[rust-timer]

Finished benchmarking commit (397937d): 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%	[-0.5%, -0.2%]	28
Improvements ✅ (secondary)	-0.4%	[-0.7%, -0.2%]	28
All ❌✅ (primary)	-0.3%	[-0.5%, -0.2%]	28

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
Regressions ❌ (secondary)	4.2%	[4.2%, 4.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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)	2.1%	[2.1%, 2.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 650.786s -> 649.393s (-0.21%)
Artifact size: 310.96 MiB -> 310.95 MiB (-0.00%)

[matthiaskrgr]

might have fixed #84727

[yotamofek]

Apparently, it also broke cargo test for nalgebra. I used cargo-bisect-rustc and it pointed to this PR. This is the (new) type inference error:

error[E0283]: type annotations needed for `matrix::Matrix<T, base::dimension::Const<2>, base::dimension::Const<2>, array_storage::ArrayStorage<T, 2, 2>>`
   --> src/linalg/symmetric_eigen.rs:363:17
    |
363 |             let m = Matrix2::new_random();
    |                 ^   --------------------- type must be known at this point
    |
    = note: cannot satisfy `_: base::scalar::Scalar`
note: required by a bound in `construction::<impl matrix::Matrix<T, R, C, <default_allocator::DefaultAllocator as base::allocator::Allocator<T, R, C>>::Buffer>>::new_random`
   --> src/base/construction.rs:647:9
    |
639 |         pub fn new_random($($args: usize),*) -> Self
    |                ---------- required by a bound in this associated function
...
647 | impl<T: Scalar, R: DimName, C: DimName> OMatrix<T, R, C>
    |         ^^^^^^ required by this bound in `construction::<impl Matrix<T, R, C, <DefaultAllocator as Allocator<T, R, C>>::Buffer>>::new_random`
help: consider giving `m` an explicit type, where the type for type parameter `T` is specified
    |
363 |             let m: matrix::Matrix<T, base::dimension::Const<2>, base::dimension::Const<2>, array_storage::ArrayStorage<T, 2, 2>> = Matrix2::new_random();
    |                  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

error[E0283]: type annotations needed
   --> src/linalg/symmetric_eigen.rs:364:23
    |
364 |             let m = m * m.transpose();
    |                       ^ cannot infer type for struct `matrix::Matrix<_, base::dimension::Const<2>, base::dimension::Const<2>, array_storage::ArrayStorage<_, 2, 2>>`
    |
note: multiple `impl`s satisfying `matrix::Matrix<_, base::dimension::Const<2>, base::dimension::Const<2>, array_storage::ArrayStorage<_, 2, 2>>: Mul<matrix::Matrix<_, base::dimension::Const<2>, base::dimension::Const<2>, array_storage::ArrayStorage<_, 2, 2>>>` found
   --> src/base/ops.rs:458:9
    |
458 | /         impl<T, R: Dim, C: Dim, S> $Trait<T> for Matrix<T, R, C, S>
459 | |             where T: Scalar + $bound,
460 | |                   S: Storage<T, R, C>,
461 | |                   DefaultAllocator: Allocator<T, R, C> {
    | |______________________________________________________^
...
509 |   componentwise_scalarop_impl!(Mul, mul, ClosedMul; MulAssign, mul_assign);
    |   ------------------------------------------------------------------------ in this macro invocation
...
607 | / impl<T, R1: Dim, C1: Dim, R2: Dim, C2: Dim, SA, SB> Mul<Matrix<T, R2, C2, SB>>
608 | |     for Matrix<T, R1, C1, SA>
609 | | where
610 | |     T: Scalar + Zero + One + ClosedAdd + ClosedMul,
...   |
613 | |     DefaultAllocator: Allocator<T, R1, C2>,
614 | |     ShapeConstraint: AreMultipliable<R1, C1, R2, C2>,
    | |_____________________________________________________^
    = note: this error originates in the macro `componentwise_scalarop_impl` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0283`.

The fix for nalgebra is simple, but I'm just wondering if this is something that should have been picked up by crater, and fixed before this PR was merged.

[lcnr]

for relnotes: this is small change to our type inference with the intent to cleanup the type system and to simplify future development.

wrt to #119989 (comment), opened a topic on zulip to maybe build tests when running crater in check mode. https://rust-lang.zulipchat.com/#narrow/stream/242791-t-infra/topic/crater.3A.20tests.20in.20check.20builds