New const traits syntax #139858

oli-obk · 2025-04-15T09:02:09Z

This PR only affects the AST and doesn't actually change anything semantically.

All occurrences of ~const outside of libcore have been replaced by [const]. Within libcore we have to wait for rustfmt to be bumped in the bootstrap compiler. This will happen "automatically" (when rustfmt is run) during the bootstrap bump, as rustfmt converts ~const into [const]. After this we can remove the ~const support from the parser

Caveat discovered during impl: there is no legacy bare trait object recovery for [const] Trait as that snippet in type position goes down the slice /array parsing code and will error

r? @fee1-dead

cc @nikomatsakis @traviscross @compiler-errors

rustbot · 2025-04-15T09:02:17Z

Some changes occurred in src/tools/rustfmt

cc @rust-lang/rustfmt

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

compiler/rustc_ast/src/ast.rs

tests/ui/const-generics/const_trait_fn-issue-88433.rs

src/tools/clippy/clippy_utils/src/ast_utils/mod.rs

bors · 2025-05-06T10:43:05Z

☔ The latest upstream changes (presumably #140695) made this pull request unmergeable. Please resolve the merge conflicts.

compiler-errors · 2025-05-22T09:37:39Z

Have we actually settled on a syntax here? Sorry for punting it back over, but would like to get an update here if it's actually ready to review :> ping me when it's ready, sorry for the delays!

@rustbot author

rustbot · 2025-05-22T09:37:43Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

traviscross · 2025-05-22T14:34:16Z

Have we actually settled on a syntax here?

No. Discussion is ongoing.

oli-obk · 2025-06-26T10:26:00Z

@rustbot ready

rustbot · 2025-06-26T10:45:28Z

There are changes to the tidy tool.

cc @jieyouxu

fee1-dead · 2025-06-27T09:35:17Z

@bors r+ rollup=never

bors · 2025-06-27T09:35:21Z

📌 Commit 512ff95 has been approved by fee1-dead

It is now in the queue for this repository.

compiler-errors · 2025-06-27T17:01:36Z

This affects a lot of tests but I don't expect it to fail, except if there's an untested doc test or something.

@bors rollup=iffy

…=fee1-dead New const traits syntax This PR only affects the AST and doesn't actually change anything semantically. All occurrences of `~const` outside of libcore have been replaced by `[const]`. Within libcore we have to wait for rustfmt to be bumped in the bootstrap compiler. This will happen "automatically" (when rustfmt is run) during the bootstrap bump, as rustfmt converts `~const` into `[const]`. After this we can remove the `~const` support from the parser Caveat discovered during impl: there is no legacy bare trait object recovery for `[const] Trait` as that snippet in type position goes down the slice /array parsing code and will error r? `@fee1-dead` cc `@nikomatsakis` `@traviscross` `@compiler-errors`

…rors Rollup of 8 pull requests Successful merges: - #139858 (New const traits syntax) - #140809 (Reduce special casing for the panic runtime) - #142963 (Skip unnecessary components in x64 try builds) - #142974 (Update stage0 to 1.89.0-beta.1) - #142987 (rustdoc: show attributes on enum variants) - #143002 (tests: Require `run-fail` ui tests to have an exit code (`SIGABRT` not ok)) - #143092 (const checks for lifetime-extended temporaries: avoid 'top-level scope' terminology) - #143096 (tag_for_variant: properly pass TypingEnv) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 9 pull requests Successful merges: - #139858 (New const traits syntax) - #140809 (Reduce special casing for the panic runtime) - #142730 (suggest declaring modules when file found but module not defined) - #142806 (Normalize before computing ConstArgHasType goal in new solver) - #143046 (const validation: properly ignore zero-sized UnsafeCell) - #143092 (const checks for lifetime-extended temporaries: avoid 'top-level scope' terminology) - #143096 (tag_for_variant: properly pass TypingEnv) - #143104 (hir_analysis: prohibit `dyn PointeeSized`) - #143106 (gce: don't ICE on non-local const) Failed merges: - #143036 (Remove support for `dyn*` from the compiler) r? `@ghost` `@rustbot` modify labels: rollup

bors · 2025-06-28T02:19:45Z

⌛ Testing commit 512ff95 with merge d41e12f...

Rollup merge of #139858 - oli-obk:new-const-traits-syntax, r=fee1-dead New const traits syntax This PR only affects the AST and doesn't actually change anything semantically. All occurrences of `~const` outside of libcore have been replaced by `[const]`. Within libcore we have to wait for rustfmt to be bumped in the bootstrap compiler. This will happen "automatically" (when rustfmt is run) during the bootstrap bump, as rustfmt converts `~const` into `[const]`. After this we can remove the `~const` support from the parser Caveat discovered during impl: there is no legacy bare trait object recovery for `[const] Trait` as that snippet in type position goes down the slice /array parsing code and will error r? ``@fee1-dead`` cc ``@nikomatsakis`` ``@traviscross`` ``@compiler-errors``

Rollup of 9 pull requests Successful merges: - rust-lang/rust#139858 (New const traits syntax) - rust-lang/rust#140809 (Reduce special casing for the panic runtime) - rust-lang/rust#142730 (suggest declaring modules when file found but module not defined) - rust-lang/rust#142806 (Normalize before computing ConstArgHasType goal in new solver) - rust-lang/rust#143046 (const validation: properly ignore zero-sized UnsafeCell) - rust-lang/rust#143092 (const checks for lifetime-extended temporaries: avoid 'top-level scope' terminology) - rust-lang/rust#143096 (tag_for_variant: properly pass TypingEnv) - rust-lang/rust#143104 (hir_analysis: prohibit `dyn PointeeSized`) - rust-lang/rust#143106 (gce: don't ICE on non-local const) Failed merges: - rust-lang/rust#143036 (Remove support for `dyn*` from the compiler) r? `@ghost` `@rustbot` modify labels: rollup

rustbot assigned compiler-errors Apr 15, 2025

oli-obk commented Apr 15, 2025

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traviscross reviewed Apr 16, 2025

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traviscross mentioned this pull request Apr 16, 2025

Make trait methods callable in const contexts rust-lang/rfcs#3762

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Extract const boundness parsing out into a method

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oli-obk added 2 commits June 26, 2025 13:46

Change const trait bound syntax from ~const to [const]

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Rename tilde const test files to conditionally const

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fee1-dead approved these changes Jun 27, 2025

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compiler-errors mentioned this pull request Jun 27, 2025

Rollup of 8 pull requests #143105

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matthiaskrgr mentioned this pull request Jun 27, 2025

Rollup of 9 pull requests #143116

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bors merged commit 36c2b01 into rust-lang:master Jun 28, 2025
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rustbot added this to the 1.90.0 milestone Jun 28, 2025

New const traits syntax #139858

New const traits syntax #139858

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