mGCA: Support array expression as direct const arguments #150786

reddevilmidzy · 2026-01-08T02:02:27Z

tracking issue: #132980
resolve: #150612

Support array expression as direct const arguments (e. g. [1, 2, N]) in min_generic_const_args.

todo:

Rebase another mGCA PR
Add more test case
Modify clippy code

rust-bors · 2026-01-08T10:01:37Z

☔ The latest upstream changes (presumably #150798) made this pull request unmergeable. Please resolve the merge conflicts.

BoxyUwU · 2026-01-08T15:21:03Z

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

+        let tcx = self.tcx();
+
+        let array_len = array_expr.elems.len() as u64;
+        let elem_ty = self.ty_infer(None, array_expr.span);


using a ty_infer here isn't quite what you want, this will make it so that using array expressions in type signatures will cause an error due to having _ in your type signature.

it might be useful to look at the recent PR adding support for (N, N2, const { 1 + 1 }) to mgca which has to do very similar logic to what you need to do here: https://github.com/rust-lang/rust/pull/150675/files#diff-ce4273e1e949bf3052de7a08466c4dad785890b24091122954541b615b0ba199R2488-R2513

(you'll probably need to rebase onto latest main too to get the FeedConstTy changes :3)

Thanks for the review! I changed the type infer to use a different method than ty_infer and added related tests.

BoxyUwU · 2026-01-08T15:21:31Z

Looks good so far :) thanks for taking this on

rustbot · 2026-01-09T06:59:02Z

HIR ty lowering was modified

cc @fmease

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

BoxyUwU · 2026-01-09T15:13:38Z

thanks!

@bors r+ rollup

rust-bors · 2026-01-09T15:13:42Z

📌 Commit 49b8c2b has been approved by BoxyUwU

It is now in the queue for this repository.

mGCA: Support array expression as direct const arguments tracking issue: rust-lang#132980 resolve: rust-lang#150612 Support array expression as direct const arguments (e. g. [1, 2, N]) in min_generic_const_args. todo: * [x] Rebase another mGCA PR * [x] Add more test case * [x] Modify clippy code

rust-bors · 2026-01-10T01:19:25Z

☔ The latest upstream changes (presumably #150818) made this pull request unmergeable. Please resolve the merge conflicts.

This pull request was unapproved.

mGCA: Support array expression as direct const arguments tracking issue: rust-lang#132980 resolve: rust-lang#150612 Support array expression as direct const arguments (e. g. [1, 2, N]) in min_generic_const_args. todo: * [x] Rebase another mGCA PR * [x] Add more test case * [x] Modify clippy code

@ghost

Rollup of 14 pull requests Successful merges: - #148941 (stabilize `Peekable::next_if_map` (`#![feature(peekable_next_if_map)]`)) - #150368 (adding Ordering enum to minicore.rs, importing minicore in "tests/assembly-llvm/rust-abi-arg-attr.rs" test file) - #150668 (Unix implementation for stdio set/take/replace) - #150743 (Reword the collect() docs) - #150776 (Fix the connect_error test on FreeBSD 15+) - #150781 (Use `rand` crate more idiomatically) - #150786 (mGCA: Support array expression as direct const arguments) - #150812 (Bump `diesel` to the most recent commit in `cargotest`) - #150862 (std: sys: fs: uefi: Implement File::flush) - #150873 (Reenable GCC CI download) - #150908 (llvm: Update `reliable_f16` configuration for LLVM22) - #150918 (std: sys: fs: uefi: Implement File::seek) - #150922 (Subscribe myself to attr parsing) - #150930 (Remove special case for `AllowedTargets::CrateLevel`) r? @ghost

matthiaskrgr · 2026-01-11T08:58:24Z

@bors r-
looke like this failed here? #150952 (comment)

rust-bors · 2026-01-11T08:58:27Z

Commit f2f45ff has been unapproved.

Zalathar · 2026-01-11T09:03:00Z

Though note that the same job previously succeeded in #150948 (comment), so it might be flaky.

@bors try jobs=x86_64-mingw-1

mGCA: Support array expression as direct const arguments try-job: x86_64-mingw-1

rust-bors · 2026-01-11T11:53:29Z

☀️ Try build successful (CI)
Build commit: 69e457f (69e457f0cdcb1773572306926cc50b0547aaf7c4, parent: 9bc8b40bc314b74e1d5e5ab21a0df39c55a34806)

BoxyUwU · 2026-01-11T12:07:28Z

I don't see anything in this PR that could cause that test to fail 🤔 Going to re-approve this PR, if that test is flakily failing (which it seems so) we should probably disable it so it stops causing rollups to fail.

@bors r+

rust-bors · 2026-01-11T12:07:31Z

📌 Commit f2f45ff has been approved by BoxyUwU

It is now in the queue for this repository.

BoxyUwU · 2026-01-11T12:09:03Z

though
@bors rollup=never
just in case this PR for some reason actually is causing problems here

rust-bors · 2026-01-12T16:42:59Z

☀️ Test successful - CI
Approved by: BoxyUwU
Pushing 1377169 to main...

github-actions · 2026-01-12T16:45:34Z

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 b115ea2 (parent) -> 1377169 (this PR)

Test differences

Show 38 test diffs

Stage 1

[ui] tests/ui/const-generics/mgca/array-expr-complex.rs: [missing] -> pass (J1)
[ui] tests/ui/const-generics/mgca/array-expr-empty.rs: [missing] -> pass (J1)
[ui] tests/ui/const-generics/mgca/array-expr-simple.rs: [missing] -> pass (J1)
[ui] tests/ui/const-generics/mgca/array-expr-with-assoc-const.rs: [missing] -> pass (J1)
[ui] tests/ui/const-generics/mgca/array-expr-with-macro.rs: [missing] -> pass (J1)
[ui] tests/ui/const-generics/mgca/array-expr-with-struct.rs: [missing] -> pass (J1)
[ui] tests/ui/const-generics/mgca/array-expr-with-tuple.rs: [missing] -> pass (J1)

Stage 2

[ui] tests/ui/const-generics/mgca/array-expr-complex.rs: [missing] -> pass (J0)
[ui] tests/ui/const-generics/mgca/array-expr-empty.rs: [missing] -> pass (J0)
[ui] tests/ui/const-generics/mgca/array-expr-simple.rs: [missing] -> pass (J0)
[ui] tests/ui/const-generics/mgca/array-expr-with-assoc-const.rs: [missing] -> pass (J0)
[ui] tests/ui/const-generics/mgca/array-expr-with-macro.rs: [missing] -> pass (J0)
[ui] tests/ui/const-generics/mgca/array-expr-with-struct.rs: [missing] -> pass (J0)
[ui] tests/ui/const-generics/mgca/array-expr-with-tuple.rs: [missing] -> pass (J0)

Additionally, 24 doctest diffs were found. These are ignored, as they are noisy.

Job group index

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 137716908d561bfcf0341701ec13a28326926c82 --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

dist-x86_64-apple: 6736.5s -> 9701.5s (+44.0%)
dist-aarch64-apple: 9467.1s -> 7232.2s (-23.6%)
pr-check-1: 1687.7s -> 2022.8s (+19.9%)
i686-gnu-2: 5166.9s -> 6024.6s (+16.6%)
dist-apple-various: 4969.1s -> 4200.1s (-15.5%)
x86_64-gnu-gcc: 3024.7s -> 3453.5s (+14.2%)
x86_64-rust-for-linux: 2692.8s -> 3052.4s (+13.4%)
x86_64-gnu-llvm-20: 4285.7s -> 4802.3s (+12.1%)
aarch64-gnu-debug: 3748.6s -> 4191.2s (+11.8%)
arm-android: 5756.9s -> 6426.3s (+11.6%)

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 · 2026-01-12T17:24:24Z

Finished benchmarking commit (1377169): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

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

Cycles

Results (secondary 3.3%)

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

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.3%	[3.3%, 3.3%]	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: 473.644s -> 473.493s (-0.03%)
Artifact size: 391.40 MiB -> 391.40 MiB (-0.00%)

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reddevilmidzy force-pushed the mgca-array branch from 71bf175 to 059e616 Compare January 8, 2026 02:21

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rustbot added the T-clippy Relevant to the Clippy team. label Jan 8, 2026

BoxyUwU self-assigned this Jan 8, 2026

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reddevilmidzy force-pushed the mgca-array branch 2 times, most recently from 9fdd556 to 21e092f Compare January 9, 2026 04:16

reddevilmidzy changed the title ~~MGCA: Support array expression as direct const arguments~~ mGCA: Support array expression as direct const arguments Jan 9, 2026

reddevilmidzy force-pushed the mgca-array branch from ecca57d to 49b8c2b Compare January 9, 2026 05:26

reddevilmidzy marked this pull request as ready for review January 9, 2026 06:58

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tgross35 mentioned this pull request Jan 9, 2026

Rollup of 9 pull requests #150901

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rust-bors bot 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-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jan 10, 2026

reddevilmidzy added 2 commits January 10, 2026 12:41

Introduce hir::ConstArgKind::Array

fc06a57

Lower hir::ConstArgKind::Array to a ValTree

618b0b5

Zalathar mentioned this pull request Jan 10, 2026

Rollup of 15 pull requests #150914

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JonathanBrouwer mentioned this pull request Jan 10, 2026

Rollup of 14 pull requests #150924

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Zalathar mentioned this pull request Jan 11, 2026

[EXPERIMENT] Rollup of 15 pull requests #150948

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Zalathar mentioned this pull request Jan 11, 2026

Rollup of 14 pull requests #150952

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rust-bors bot added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Jan 11, 2026

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rust-bors bot added a commit that referenced this pull request Jan 11, 2026

Auto merge of #150786 - reddevilmidzy:mgca-array, r=<try>

69e457f

mGCA: Support array expression as direct const arguments try-job: x86_64-mingw-1

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rust-bors bot added the merged-by-bors This PR was explicitly merged by bors. label Jan 12, 2026

rust-bors bot merged commit 1377169 into rust-lang:main Jan 12, 2026
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rustbot added this to the 1.94.0 milestone Jan 12, 2026

reddevilmidzy deleted the mgca-array branch January 13, 2026 06:08

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