Migrate `UnsizedConstParamTy` to unstable impl of `ConstParamTy_` #145095

tiif · 2025-08-08T13:10:21Z

Now that we have #[unstable_feature_bound], we can remove UnsizedConstParamTy that was meant to be an unstable impl of stable type and ConstParamTy_ trait.

r? @BoxyUwU

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? `@BoxyUwU`

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ``@BoxyUwU``

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ```@BoxyUwU```

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ````@BoxyUwU````

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? `````@BoxyUwU`````

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ``````@BoxyUwU``````

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ```````@BoxyUwU```````

Rollup merge of #145251 - tiif:support_trait, r=BoxyUwU Support using #[unstable_feature_bound] on trait This is needed to unblock #145095 r? ```````@BoxyUwU```````

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang/rust#145095 r? ```````@BoxyUwU```````

compiler/rustc_hir_analysis/src/check/wfcheck.rs

tiif · 2025-08-22T20:51:04Z

Currently all tests in tests/ui passed locally, but some test change feels suspicious, will take a closer look soon 🤔

bors · 2025-08-23T09:22:49Z

☔ The latest upstream changes (presumably #145773) made this pull request unmergeable. Please resolve the merge conflicts.

library/core/src/tuple.rs

compiler/rustc_hir_analysis/src/check/wfcheck.rs

tests/ui/const-generics/adt_const_params/unsized_field-1.rs

tests/ui/feature-gates/feature-gate-unsized-const-params.rs

tests/ui/layout/thaw-transmute-invalid-enum.stderr

compiler/rustc_trait_selection/src/traits/misc.rs

library/core/src/tuple.rs

compiler/rustc_hir_analysis/src/check/wfcheck.rs

tests/ui/const-generics/adt_const_params/unsized_field-1.rs

compiler/rustc_hir_analysis/src/coherence/builtin.rs

tests/ui/feature-gates/feature-gate-adt_const_params.stderr

compiler/rustc_trait_selection/src/traits/misc.rs

tests/ui/const-generics/generic_const_parameter_types/check-type-in-mir.stderr

tiif · 2025-09-12T06:48:46Z

tests/ui/feature-gates/feature-gate-unsized-const-params.stderr

+error[E0741]: `Bar` must implement `ConstParamTy` to be used as the type of a const generic parameter
+  --> $DIR/feature-gate-unsized-const-params.rs:5:21
   |
-LL | struct Foo<const N: [u8]>;
-   |                     ^^^^
+LL | struct Foo<const N: Bar>;
+   |                     ^^^
   |
-   = note: the only supported types are integers, `bool`, and `char`
-help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#[derive(ConstParamTy, PartialEq, Eq)]` to the struct
   |
-LL + #![feature(adt_const_params)]
-   |
-help: add `#![feature(unsized_const_params)]` to the crate attributes to enable references to implement the `ConstParamTy` trait
-   |
-LL + #![feature(unsized_const_params)]
+LL - struct Bar(u8);
+LL + #[derive(ConstParamTy, PartialEq, Eq)]


The suggestion here is a bit weird,

LL - struct Bar(u8); LL + #[derive(ConstParamTy, PartialEq, Eq)]

but feels like a pre-existing issue, can take a look at this after tihs PR.

fascinating I wonder what's going on here

…with #[unstable_feature_bound(unsized_const_params)]

tests/ui/feature-gates/feature-gate-unsized-const-params.rs

BoxyUwU · 2025-09-15T15:51:13Z

tests/ui/const-generics/adt_const_params/unsized_field-1.stderr

 LL | struct A([u8]);
   |          ---- this field does not implement `ConstParamTy_`
+   |
+note: the `ConstParamTy_` impl for `[u8]` requires that `unstable feature: `unsized_const_params``


we should probably make the diagnostic for unsatisfied UnstableFeature clauses be worded a bit nicer. different PR though

BoxyUwU · 2025-09-15T15:52:01Z

@bors r+

thanks gamer :3 very cool

bors · 2025-09-15T15:52:04Z

📌 Commit 7299e8f has been approved by BoxyUwU

It is now in the queue for this repository.

Rollup of 9 pull requests Successful merges: - #145095 (Migrate `UnsizedConstParamTy` to unstable impl of `ConstParamTy_`) - #145960 (Split `FnCtxt::report_args_error` into subfunctions) - #146402 (interpret: fix overlapping aggregate initialization) - #146466 (llvm-wrapper: other cleanup) - #146574 (compiletest: Enable new-output-capture by default) - #146599 (replace some `#[const_trait]` with `const trait`) - #146601 (compiletest: Make `./x test --test-args ...` work again) - #146608 (improve internal bootstrap docs) - #146609 (bootstrap: lower verbosity of cargo to one less than bootstrap's) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #145095 - tiif:unstable_const_param, r=BoxyUwU Migrate `UnsizedConstParamTy` to unstable impl of `ConstParamTy_` Now that we have ``#[unstable_feature_bound]``, we can remove ``UnsizedConstParamTy`` that was meant to be an unstable impl of stable type and ``ConstParamTy_`` trait. r? `@BoxyUwU`

Rollup of 9 pull requests Successful merges: - rust-lang/rust#145095 (Migrate `UnsizedConstParamTy` to unstable impl of `ConstParamTy_`) - rust-lang/rust#145960 (Split `FnCtxt::report_args_error` into subfunctions) - rust-lang/rust#146402 (interpret: fix overlapping aggregate initialization) - rust-lang/rust#146466 (llvm-wrapper: other cleanup) - rust-lang/rust#146574 (compiletest: Enable new-output-capture by default) - rust-lang/rust#146599 (replace some `#[const_trait]` with `const trait`) - rust-lang/rust#146601 (compiletest: Make `./x test --test-args ...` work again) - rust-lang/rust#146608 (improve internal bootstrap docs) - rust-lang/rust#146609 (bootstrap: lower verbosity of cargo to one less than bootstrap's) r? `@ghost` `@rustbot` modify labels: rollup

rustbot assigned BoxyUwU Aug 8, 2025

This comment has been minimized.

Sign in to view

tiif mentioned this pull request Aug 11, 2025

Support using #[unstable_feature_bound] on trait #145251

Merged

fmease added a commit to fmease/rust that referenced this pull request Aug 11, 2025

Rollup merge of rust-lang#145251 - tiif:support_trait, r=BoxyUwU

6434c4b

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? `@BoxyUwU`

fmease added a commit to fmease/rust that referenced this pull request Aug 12, 2025

Rollup merge of rust-lang#145251 - tiif:support_trait, r=BoxyUwU

0bce3c2

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ``@BoxyUwU``

fmease added a commit to fmease/rust that referenced this pull request Aug 12, 2025

Rollup merge of rust-lang#145251 - tiif:support_trait, r=BoxyUwU

5238288

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ```@BoxyUwU```

fmease added a commit to fmease/rust that referenced this pull request Aug 12, 2025

Rollup merge of rust-lang#145251 - tiif:support_trait, r=BoxyUwU

b1777e3

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ````@BoxyUwU````

fmease added a commit to fmease/rust that referenced this pull request Aug 12, 2025

Rollup merge of rust-lang#145251 - tiif:support_trait, r=BoxyUwU

556c571

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? `````@BoxyUwU`````

Zalathar added a commit to Zalathar/rust that referenced this pull request Aug 12, 2025

Rollup merge of rust-lang#145251 - tiif:support_trait, r=BoxyUwU

cfae921

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ``````@BoxyUwU``````

Zalathar added a commit to Zalathar/rust that referenced this pull request Aug 12, 2025

Rollup merge of rust-lang#145251 - tiif:support_trait, r=BoxyUwU

42af95b

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang#145095 r? ```````@BoxyUwU```````

rust-timer added a commit that referenced this pull request Aug 12, 2025

Unrolled build for #145251

8d9c2b1

Rollup merge of #145251 - tiif:support_trait, r=BoxyUwU Support using #[unstable_feature_bound] on trait This is needed to unblock #145095 r? ```````@BoxyUwU```````

github-actions bot pushed a commit to rust-lang/miri that referenced this pull request Aug 13, 2025

Rollup merge of #145251 - tiif:support_trait, r=BoxyUwU

8131632

Support using #[unstable_feature_bound] on trait This is needed to unblock rust-lang/rust#145095 r? ```````@BoxyUwU```````

rust-cloud-vms bot force-pushed the unstable_const_param branch from a4bd0a8 to 262cf11 Compare August 18, 2025 15:00

BoxyUwU reviewed Aug 19, 2025

View reviewed changes

compiler/rustc_hir_analysis/src/check/wfcheck.rs Outdated Show resolved Hide resolved

tiif commented Aug 31, 2025

View reviewed changes

library/core/src/tuple.rs Show resolved Hide resolved

compiler/rustc_hir_analysis/src/check/wfcheck.rs Outdated Show resolved Hide resolved

tiif commented Sep 2, 2025

View reviewed changes

tests/ui/const-generics/adt_const_params/unsized_field-1.rs Show resolved Hide resolved

tests/ui/feature-gates/feature-gate-unsized-const-params.rs Show resolved Hide resolved

tests/ui/layout/thaw-transmute-invalid-enum.stderr Show resolved Hide resolved

BoxyUwU reviewed Sep 2, 2025

View reviewed changes

BoxyUwU reviewed Sep 10, 2025

View reviewed changes

tests/ui/const-generics/generic_const_parameter_types/check-type-in-mir.stderr Show resolved Hide resolved

tiif commented Sep 12, 2025

View reviewed changes

rust-cloud-vms bot force-pushed the unstable_const_param branch from 8d88452 to 1f70531 Compare September 13, 2025 14:31

This comment has been minimized.

Sign in to view

tiif added 3 commits September 15, 2025 08:57

Remove UnsizedConstParamTy trait and make it into an unstable impl

b919a5f

Add check to make sure ConstParamTy impls of certain types are gated …

1a02cd5

…with #[unstable_feature_bound(unsized_const_params)]

Fix the testcases to not use UnsizedConstParamTy

0bd2ee3

Add documentation for select_where_possible and select_all_or_error

1c30399

rust-cloud-vms bot force-pushed the unstable_const_param branch from 379e7ea to 1c30399 Compare September 15, 2025 09:02

tiif marked this pull request as ready for review September 15, 2025 09:14

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 15, 2025

BoxyUwU reviewed Sep 15, 2025

View reviewed changes

tests/ui/feature-gates/feature-gate-unsized-const-params.rs Outdated Show resolved Hide resolved

Fix feature gate tests

7299e8f

BoxyUwU reviewed Sep 15, 2025

View reviewed changes

bors 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 15, 2025

Zalathar mentioned this pull request Sep 16, 2025

Rollup of 9 pull requests #146614

Merged

bors merged commit edd6721 into rust-lang:master Sep 16, 2025
10 checks passed

rustbot added this to the 1.92.0 milestone Sep 16, 2025

tiif mentioned this pull request Sep 19, 2025

Improve the pretty print of UnstableFeature clause #146753

Open

Migrate UnsizedConstParamTy to unstable impl of ConstParamTy_ #145095

Migrate UnsizedConstParamTy to unstable impl of ConstParamTy_ #145095

Uh oh!

Conversation

tiif commented Aug 8, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

This comment has been minimized.

Uh oh!

tiif commented Aug 22, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

bors commented Aug 23, 2025

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

tiif Sep 12, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

BoxyUwU Sep 15, 2025

Choose a reason for hiding this comment

Uh oh!

This comment has been minimized.

Uh oh!

BoxyUwU Sep 15, 2025

Choose a reason for hiding this comment

Uh oh!

BoxyUwU commented Sep 15, 2025

Uh oh!

bors commented Sep 15, 2025

Uh oh!

Uh oh!

Uh oh!

Migrate `UnsizedConstParamTy` to unstable impl of `ConstParamTy_` #145095

Migrate `UnsizedConstParamTy` to unstable impl of `ConstParamTy_` #145095

tiif commented Aug 8, 2025 •

edited

Loading

tiif commented Aug 22, 2025 •

edited

Loading

tiif Sep 12, 2025 •

edited

Loading