reintroduce check RibKind::ConstParamTy did in direct consts by khyperia · Pull Request #162842 · rust-lang/rust

khyperia · 2026-09-16T07:00:26Z

The ConstParamTy nameres rib checks were never implemented for gca!-rhs direct consts. So, when type const got removed in #162517 and we now only have gca!-rhs direct consts, the lack of checks became very apparent
This PR adds the check again for gca!-rhs direct consts.

When implementing this and updating tests/ui/const-generics/mgca/type_const-generic-param-in-type.rs, I ran into #160553 which caused a glaringly obvious issue - the following succeeds compilation:

#![feature(min_generic_const_args, generic_const_items, generic_const_parameter_types)]
const BAR<const N: usize>: [(); N] = core::direct_const_arg!([]);

This is already tracked in tests/crashes/160553.rs so I have not added a test for it.

This is the reason I changed the test from [(); N] to StructWithConstParam<const N: usize>, the RHS has to, like, y'know, actually typecheck :P

r? @BoxyUwU

rustbot · 2026-09-16T07:00:31Z

HIR ty lowering was modified

cc @fmease

rustbot · 2026-09-16T07:00:34Z

BoxyUwU is currently at their maximum review capacity.
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khyperia · 2026-09-16T09:01:04Z

When implementing this and updating tests/ui/const-generics/mgca/type_const-generic-param-in-type.rs, I ran into #160553 which caused a glaringly obvious issue

opened a PR to fix this #162845

BoxyUwU

r=me with comment

View changes since this review

BoxyUwU · 2026-09-16T10:10:58Z

+                tcx.require_lang_item(LangItem::ConstParamTy, span),
+            );
+        }
+        if !tcx.features().generic_const_parameter_types() && item_ty.has_param() {


can you add a FIXME about how we might want to move this to type_of so we can return Error from type_of if it references invalid params

// FIXME(min_generic_const_args): We *might* want to move this check to `type_of`, so we can // return `ty::Error` if it references invalid params. However, doing so is hard, because // `type_of` doesn't know if it's a direct const - `const_of_item` determines that, and // `const_of_item` calls `type_of`.

khyperia · 2026-09-17T05:06:46Z

@bors r=BoxyUwU rollup

rust-bors · 2026-09-17T05:06:49Z

📌 Commit 9dce1fc has been approved by BoxyUwU

It is now in the queue for this repository.

@BoxyUwU

…yUwU reintroduce check RibKind::ConstParamTy did in direct consts The ConstParamTy nameres rib checks were never implemented for `gca!`-rhs direct consts. So, when `type const` got removed in rust-lang#162517 and we now only have `gca!`-rhs direct consts, the lack of checks became very apparent This PR adds the check again for `gca!`-rhs direct consts. When implementing this and updating `tests/ui/const-generics/mgca/type_const-generic-param-in-type.rs`, I ran into rust-lang#160553 which caused a glaringly obvious issue - the following succeeds compilation: ```rust #![feature(min_generic_const_args, generic_const_items, generic_const_parameter_types)] const BAR<const N: usize>: [(); N] = core::direct_const_arg!([]); ``` This is already tracked in `tests/crashes/160553.rs` so I have not added a test for it. This is the reason I changed the test from `[(); N]` to `StructWithConstParam<const N: usize>`, the RHS has to, like, y'know, actually typecheck :P r? @BoxyUwU

Rollup of 16 pull requests Successful merges: - #161596 (coretests: Add more pattern tests.) - #162796 (libtest: do not early exit from test runners) - #162844 (Add loan reachability traces to polonius MIR dumps) - #162876 (Move operations out of `rustc_middle::query::job`) - #160108 (Stabilize `windows_process_extensions_main_thread_handle`) - #160212 (traits: Fix rigid alias liveness matching) - #160544 (Stabilize `feature(trim_prefix_suffix)` (`{str, [T], Path}::trim_prefix` and `{str, [T]}::trim_suffix`)) - #161246 (Normalize non-rigid aliases in ty_known_to_outlive) - #161305 (Use the entire type of a dropped local to compute variance (edge direction) for Polonius alpha) - #161838 (tests: accept LLVM 24 optimization in this test) - #162805 (Add `must_use` lint to `ExitCode`) - #162825 (core: Add examples for `debug_closure_helpers`) - #162841 (enable asm tests for xtensa targets) - #162842 (reintroduce check RibKind::ConstParamTy did in direct consts) - #162845 (mgca: fix issue with mismatched array valtree/valtree tys) - #162856 (Stabilize CommandExt::show_window)

@BoxyUwU

…yUwU reintroduce check RibKind::ConstParamTy did in direct consts The ConstParamTy nameres rib checks were never implemented for `gca!`-rhs direct consts. So, when `type const` got removed in rust-lang#162517 and we now only have `gca!`-rhs direct consts, the lack of checks became very apparent This PR adds the check again for `gca!`-rhs direct consts. When implementing this and updating `tests/ui/const-generics/mgca/type_const-generic-param-in-type.rs`, I ran into rust-lang#160553 which caused a glaringly obvious issue - the following succeeds compilation: ```rust #![feature(min_generic_const_args, generic_const_items, generic_const_parameter_types)] const BAR<const N: usize>: [(); N] = core::direct_const_arg!([]); ``` This is already tracked in `tests/crashes/160553.rs` so I have not added a test for it. This is the reason I changed the test from `[(); N]` to `StructWithConstParam<const N: usize>`, the RHS has to, like, y'know, actually typecheck :P r? @BoxyUwU

…uwer Rollup of 24 pull requests Successful merges: - #161596 (coretests: Add more pattern tests.) - #162177 (Properly implement the gpu-kernel ABI for amdgpu) - #162411 (Make Receiver `#[rustc_dyn_incompatible_trait]`) - #162760 (yeet alias new_from_def_id) - #162796 (libtest: do not early exit from test runners) - #162844 (Add loan reachability traces to polonius MIR dumps) - #162876 (Move operations out of `rustc_middle::query::job`) - #160108 (Stabilize `windows_process_extensions_main_thread_handle`) - #160212 (traits: Fix rigid alias liveness matching) - #160544 (Stabilize `feature(trim_prefix_suffix)` (`{str, [T], Path}::trim_prefix` and `{str, [T]}::trim_suffix`)) - #161305 (Use the entire type of a dropped local to compute variance (edge direction) for Polonius alpha) - #161838 (tests: accept LLVM 24 optimization in this test) - #162312 (core: Rewrite docs for try_as_dyn) - #162785 (Avoid creating overlapping assignments in MatchBranchSimplification) - #162805 (Add `must_use` lint to `ExitCode`) - #162825 (core: Add examples for `debug_closure_helpers`) - #162841 (enable asm tests for xtensa targets) - #162842 (reintroduce check RibKind::ConstParamTy did in direct consts) - #162845 (mgca: fix issue with mismatched array valtree/valtree tys) - #162856 (Stabilize CommandExt::show_window) - #162865 (Complex conjugate, negation and default) - #162874 (Add support for `annotate_snippets::snippet::AnnotationKind::Visible`) - #162881 (Simplify the macro for forwarding Decoder methods ) - #162888 (Fix a typo on the Armv7-R platform docs page)

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. labels Sep 16, 2026

rustbot assigned BoxyUwU Sep 16, 2026

khyperia changed the title ~~reintroduce check for ConstParamTy in direct consts~~ reintroduce check RibKind::ConstParamTy did in direct consts Sep 16, 2026

BoxyUwU approved these changes Sep 16, 2026

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reintroduce check for ConstParamTy in direct consts

9dce1fc

khyperia force-pushed the ConstParamTy-check branch from defba82 to 9dce1fc Compare September 16, 2026 10:20

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 17, 2026

Zalathar mentioned this pull request Sep 17, 2026

Rollup of 16 pull requests #162887

Closed

khyperia mentioned this pull request Sep 17, 2026

[Work Item]: ConstParamTy checks for type of direct const items is unchecked/unimplemented rust-lang/project-const-generics#120

Closed

JonathanBrouwer mentioned this pull request Sep 17, 2026

Rollup of 24 pull requests #162893

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reintroduce check RibKind::ConstParamTy did in direct consts - #162842

reintroduce check RibKind::ConstParamTy did in direct consts#162842
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khyperia:ConstParamTy-check

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