implement #![feature(gca_adts)] by khyperia · Pull Request #163427 · rust-lang/rust

khyperia · 2026-09-28T07:45:31Z

Tracking issue: #163420

rustbot · 2026-09-28T07:45:34Z

These commits modify the Cargo.lock file. Unintentional changes to Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
Otherwise, you can ignore this comment.

HIR ty lowering was modified

cc @fmease

rustbot · 2026-09-28T07:45:37Z

BoxyUwU is currently at their maximum review capacity.
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bit-aloo

LGTM 🚀 . Few nits and question.

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rustbot · 2026-09-28T11:52:30Z

changes to the core type system

cc @lcnr

Some changes occurred in const_evaluatable.rs

cc @BoxyUwU

BoxyUwU · 2026-09-28T13:17:29Z

+    const GCA_MIN_CONST_ITEMS: DirectConstArgContext = DirectConstArgContext::PATH_ANY;
+
+    /// These are allowed under `#![feature(gca_adts)]`
+    const GCA_ADTS: DirectConstArgContext = DirectConstArgContext::TUPLE_CALL


I wonder if we want a PATH_CONST_CTOR to support e.g. gca!(None) without gca_const_items even though None is a const item. Probably

View changes since the review

#![feature( gca_adts, adt_const_params, const_param_ty_unchecked, generic_const_parameter_types, )] use core::gca; fn foo<T, const N: Option<T>>() {} fn bar<T>() { foo::<T, gca!(None::<T>)>(); }

does this compile? it ought to but I don't think it will?

it does compile with PATH_CONST_CTOR! (it did not compile before I added support just now)

but see in the test I added, e.g. gca!(<MyOption>::MyNone) does not compile.

BoxyUwU · 2026-09-28T13:22:19Z

    ///
-    /// under `feature(gca_min_const_items)`, these may be inline consts as well, and should be
-    /// treated the same as anon consts.
+    /// under the generic const arg family of features, these may be inline consts as well, and


is this even true anymore, we merged the defkinds right so there's no meaningful difference anymore

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BoxyUwU · 2026-09-28T14:10:10Z

@bors r+

rust-bors · 2026-09-28T14:10:13Z

📌 Commit 9e8ca58 has been tentatively approved by BoxyUwU

It will be put into the queue for this repository once PR CI succeeds.

@BoxyUwU

implement #![feature(gca_adts)] Tracking issue: rust-lang#163420 r? @BoxyUwU

@BoxyUwU

implement #![feature(gca_adts)] Tracking issue: rust-lang#163420 r? @BoxyUwU

…uwer Rollup of 15 pull requests Successful merges: - #158936 (Add `std::fs::{Home|Media}Dirs`) - #129036 (Additional NonZero conversions) - #158997 (Avoid recording unnameable `extern crate` aliases in diagnostic metadata) - #161015 (Stabilize `funnel_shifts` (including `const`)) - #161712 (Stabilize `Result::into_{ok,err}`) - #162493 (Add support for -Zsanitizer-cfi-minimal-runtime) - #162655 (next solver: prefer to select impl candidates over global where-clause candidates) - #162862 (Fix intra doc link resolution when a doc comment is composed of both inner and outer doc comment) - #163200 (make `RustaceansAreAwesome` satisfy trait bounds) - #163331 (Move `Arc` and `Rc` into `rcs` mod) - #163427 (implement #![feature(gca_adts)]) - #163428 (do not complain about unstable target features on nightly) - #163444 (Add `stable_rustc` helper in `run-make-support`) - #163447 (Allow using different index types when reading and writing to tables) - #163450 (Force the correct type variable to never for method resolution on an adjusted never type)

@BoxyUwU

implement #![feature(gca_adts)] Tracking issue: rust-lang#163420 r? @BoxyUwU

Rollup of 9 pull requests Successful merges: - #161015 (Stabilize `funnel_shifts` (including `const`)) - #161712 (Stabilize `Result::into_{ok,err}`) - #162493 (Add support for -Zsanitizer-cfi-minimal-runtime) - #163427 (implement #![feature(gca_adts)]) - #163390 (add `automatically_derived` attribute documentation) - #163428 (do not complain about unstable target features on nightly) - #163444 (Add `stable_rustc` helper in `run-make-support`) - #163447 (Allow using different index types when reading and writing to tables) - #163459 (Stabilize vec_try_remove)

Rollup of 9 pull requests Successful merges: - rust-lang/rust#161015 (Stabilize `funnel_shifts` (including `const`)) - rust-lang/rust#161712 (Stabilize `Result::into_{ok,err}`) - rust-lang/rust#162493 (Add support for -Zsanitizer-cfi-minimal-runtime) - rust-lang/rust#163427 (implement #![feature(gca_adts)]) - rust-lang/rust#163390 (add `automatically_derived` attribute documentation) - rust-lang/rust#163428 (do not complain about unstable target features on nightly) - rust-lang/rust#163444 (Add `stable_rustc` helper in `run-make-support`) - rust-lang/rust#163447 (Allow using different index types when reading and writing to tables) - rust-lang/rust#163459 (Stabilize vec_try_remove)

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 28, 2026

rustbot assigned BoxyUwU Sep 28, 2026

khyperia mentioned this pull request Sep 28, 2026

Tracking Issue for gca_adts #163420

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bit-aloo reviewed Sep 28, 2026

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Comment thread compiler/rustc_feature/src/unstable.rs Outdated

Comment thread src/doc/unstable-book/src/language-features/gca-adts.md Outdated

Comment thread compiler/rustc_ast_lowering/src/lib.rs Outdated

Comment thread compiler/rustc_ast_lowering/src/lib.rs Outdated

khyperia force-pushed the gca-adts branch from cbab137 to e788e94 Compare September 28, 2026 11:52

BoxyUwU reviewed Sep 28, 2026

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BoxyUwU mentioned this pull request Sep 28, 2026

Add "Generic Const Args and You" rust-lang/blog.rust-lang.org#1951

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implement #![feature(gca_adts)]

9e8ca58

khyperia force-pushed the gca-adts branch from e788e94 to 9e8ca58 Compare September 28, 2026 13:53

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 28, 2026

bit-aloo approved these changes Sep 28, 2026

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BoxyUwU mentioned this pull request Sep 28, 2026

Full Const Generics rust-lang/goals#100

Open

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Sep 28, 2026

Rollup merge of rust-lang#163427 - khyperia:gca-adts, r=BoxyUwU

f298e84

implement #![feature(gca_adts)] Tracking issue: rust-lang#163420 r? @BoxyUwU

JonathanBrouwer mentioned this pull request Sep 28, 2026

Rollup of 12 pull requests #163456

Closed

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Sep 28, 2026

Rollup merge of rust-lang#163427 - khyperia:gca-adts, r=BoxyUwU

a46f0db

implement #![feature(gca_adts)] Tracking issue: rust-lang#163420 r? @BoxyUwU

JonathanBrouwer mentioned this pull request Sep 28, 2026

Rollup of 15 pull requests #163460

Closed

tgross35 mentioned this pull request Sep 29, 2026

Rollup of 9 pull requests #163465

Merged

tgross35 added a commit to tgross35/rust that referenced this pull request Sep 29, 2026

Rollup merge of rust-lang#163427 - khyperia:gca-adts, r=BoxyUwU

6cf935d

implement #![feature(gca_adts)] Tracking issue: rust-lang#163420 r? @BoxyUwU

tgross35 mentioned this pull request Sep 29, 2026

Rollup of 9 pull requests #163467

Closed

rust-bors Bot merged commit e7ac0de into rust-lang:main Sep 29, 2026
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rustbot added this to the 1.101.0 milestone Sep 29, 2026

khyperia deleted the gca-adts branch September 29, 2026 07:24

github-actions Bot mentioned this pull request Oct 3, 2026

Toolchain upgrade to nightly-2026-10-05 flux-rs/flux#1811

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implement #![feature(gca_adts)] - #163427

implement #![feature(gca_adts)]#163427
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