Reject static item as direct const generic arg by Shourya742 · Pull Request #158479 · rust-lang/rust

Shourya742 · 2026-06-27T08:30:14Z

This PR fixes the ICE and not add support for static in MGCA

rustbot · 2026-06-27T08:30:18Z

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Shourya742 · 2026-06-27T08:30:31Z

r? @BoxyUwU

rustbot · 2026-06-27T08:30:35Z

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BoxyUwU · 2026-07-08T14:10:34Z

sry for taking so long to get to this, thanks for looking into this ICE ✨

This probably merge conflicts with #158617, but more usefully it'd theoretically also let us fallback to an anon const instead of erroring if we wish 🤔 though i think for now i'd like to hold off on making the can_lower_to_direct_const_arg too clever (i.e. using name res information) which means that continuing to error feels right.

i think I would prefer for us to not handle special case statics during ast lowering in any way, and instead error during HIR ty lowering when encountering a static 🤔 im not sure I understand why I feel this way 😅 we do already have some semantic checks in HIR ty lowering about what kind of thing we resolved to (e.g. type const or non type const) so I think it just feels like we do our semantic checks there and syntactic checks in ast lowering.

can you emit these errors in HIR ty lowering instead :3

BoxyUwU · 2026-07-08T14:11:48Z

+            let msg = "complex const arguments must be placed inside of a `const` block";
+            hir::ConstArgKind::Error(self.dcx().struct_span_err(span, msg).emit())
+        } else if is_trivial_path || tcx.features().min_generic_const_args() {
            let qpath = self.lower_qpath(


cc @khyperia i don't think we handled this codepath in your PR overhauling ast lowering for mgca. we should probably be checking can_lower_to_direct_const_arg here and then also reusing the lower_expr_to_direct logic here? though it would really just be the path arms right now but still... seems nice for consistency/sharing logic 🤔

unrelated to this PR, just something i realised while reading this

View changes since the review

yus, the logic here happens to be identical even with the syntax flip PR, but, it's a very wishy-washy "happens to be correct" and you're absolutely right that these should share a codepath so they don't accidentally diverge

BoxyUwU · 2026-07-08T14:11:57Z

@rustbot author

rustbot · 2026-07-11T03:45:07Z

HIR ty lowering was modified

cc @fmease

Shourya742 · 2026-07-11T03:45:54Z

can you emit these errors in HIR ty lowering instead :3

Added

BoxyUwU · 2026-07-22T13:33:45Z

@bors r+ rollup

thx gamer :3`

rust-bors · 2026-07-22T13:33:48Z

📌 Commit fc02351 has been approved by BoxyUwU

It is now in the queue for this repository.

…uring-ast-lower-using-static-const, r=BoxyUwU Reject static item as direct const generic arg closes: rust-lang#136139 This PR fixes the ICE and not add support for static in MGCA

…uwer Rollup of 12 pull requests Successful merges: - #159712 (Subtree sync for rustc_codegen_cranelift) - #155697 (Stabilize c-variadic function definitions) - #159285 (Simplify `apply_effects_in_range`) - #159596 (unify the AST repr of type const and const RHS) - #159607 (test: update riscv32e-registers.rs for LLVM 24 MC diagnostic changes) - #159659 (Move `Limit` out of `rustc_hir`) - #159707 (fix error when a dangling ref in a ManuallyDrop is used in a pattern) - #158479 (Reject static item as direct const generic arg) - #158738 (next_trait_solver: Recover from GCE const exprs) - #159451 (Remove config cloning in compiletest) - #159646 (Increase depth for float infer var fallback hack) - #159705 (bootstrap: Prefer `cfg!(not(test))` when skipping code paths during unit tests)

JonathanBrouwer · 2026-07-22T16:01:52Z

💔 I suspect this PR failed tests as part of a rollup
@bors r-

After fixing the problem, consider running a try job for the failed job before re-approving.

Link to failure: #159723 (comment)

rust-bors · 2026-07-22T16:02:00Z

This pull request was unapproved.

This PR was contained in a rollup (#159723), which was unapproved.

View changes since this unapproval

khyperia · 2026-07-22T16:23:32Z

Ah, that’s probably due to work I did, sorry! (implementing macroless_generic_const_args)

The test should probably either use the direct_const_arg macro, or enable the macroless feature

… with static value namespace

Shourya742 · 2026-07-23T11:31:31Z

Ah, that’s probably due to work I did, sorry! (implementing macroless_generic_const_args)

The test should probably either use the direct_const_arg macro, or enable the macroless feature

enabling macroless worked like a charm 🎆 , thanks.

Shourya742 · 2026-07-23T11:37:49Z

@BoxyUwU, nugding for this. This is the job that failed: auto - x86_64-gnu-llvm-21-3.

Though I think it should be fine. After rebasing the branch locally, the test started failing, and once I enabled the macroless feature, it passed again. So I think we can go with either option.

BoxyUwU · 2026-07-23T20:38:12Z

@bors r+

yeah macroless gca seems fine to me here 👍

rust-bors · 2026-07-23T20:38:15Z

📌 Commit b4c60f0 has been approved by BoxyUwU

It is now in the queue for this repository.

…uring-ast-lower-using-static-const, r=BoxyUwU Reject static item as direct const generic arg closes: rust-lang#136139 This PR fixes the ICE and not add support for static in MGCA

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rust-cloud-vms Bot force-pushed the 2026-06-27-emit-error-during-ast-lower-using-static-const branch from 67f73a3 to c5de45f Compare June 27, 2026 14:27

BoxyUwU reviewed Jul 8, 2026

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rust-cloud-vms Bot force-pushed the 2026-06-27-emit-error-during-ast-lower-using-static-const branch from c5de45f to fc02351 Compare July 11, 2026 03:45

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BoxyUwU mentioned this pull request Jul 13, 2026

Full Const Generics rust-lang/rust-project-goals#100

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Rollup of 12 pull requests #159723

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Shourya742 added 3 commits July 23, 2026 11:13

Add test for two cases 1. const argument expression 2. const argument…

6574ec2

… with static value namespace

make sure to emit error during hir_lowering for const statics

899387f

add macroless_generic_const_args as feature

b4c60f0

rust-cloud-vms Bot force-pushed the 2026-06-27-emit-error-during-ast-lower-using-static-const branch from fc02351 to b4c60f0 Compare July 23, 2026 11:30

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jhpratt mentioned this pull request Jul 23, 2026

Rollup of 23 pull requests #159793

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jhpratt mentioned this pull request Jul 23, 2026

Rollup of 20 pull requests #159802

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