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| author | Samuel Tardieu <sam@rfc1149.net> | 2025-07-15 12:52:43 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2025-07-15 12:52:43 +0200 |
| commit | cc26852148d93e6598c174eb3df807a9e9dd8f6a (patch) | |
| tree | 1edc8f75403cbec807b89b5542e3f842bc5652f4 | |
| parent | 2e37e241792643abb837dbcaca454b0e02fc5002 (diff) | |
| parent | 000e67aafb7ae8c755387a073f34662c4f6fc335 (diff) | |
| download | rust-cc26852148d93e6598c174eb3df807a9e9dd8f6a.tar.gz rust-cc26852148d93e6598c174eb3df807a9e9dd8f6a.zip | |
Rollup merge of #143927 - oli-obk:const-dyn-trait-hir-ty, r=fmease
Preserve constness in trait objects up to hir ty lowering
r? ``@compiler-errors``
While we don't support `dyn const Trait`, we can at least also inform the user that `const Trait` is only legal for `#[const_trait] trait Trait {}`
3 files changed, 27 insertions, 3 deletions
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs index cb106962be1..364ad38556b 100644 --- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs +++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs @@ -49,7 +49,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ { } = self.lower_poly_trait_ref( &trait_bound.trait_ref, trait_bound.span, - hir::BoundConstness::Never, + trait_bound.modifiers.constness, hir::BoundPolarity::Positive, dummy_self, &mut user_written_bounds, diff --git a/tests/ui/traits/const-traits/const-trait-bounds-trait-objects.rs b/tests/ui/traits/const-traits/const-trait-bounds-trait-objects.rs index ece87529c3e..1d1da9b0e3d 100644 --- a/tests/ui/traits/const-traits/const-trait-bounds-trait-objects.rs +++ b/tests/ui/traits/const-traits/const-trait-bounds-trait-objects.rs @@ -14,5 +14,7 @@ fn main() { trait NonConst {} const fn handle(_: &dyn const NonConst) {} //~^ ERROR const trait bounds are not allowed in trait object types +//~| ERROR `const` can only be applied to `#[const_trait]` traits const fn take(_: &dyn [const] NonConst) {} //~^ ERROR `[const]` is not allowed here +//~| ERROR `[const]` can only be applied to `#[const_trait]` traits diff --git a/tests/ui/traits/const-traits/const-trait-bounds-trait-objects.stderr b/tests/ui/traits/const-traits/const-trait-bounds-trait-objects.stderr index 090555c6377..06e0493024c 100644 --- a/tests/ui/traits/const-traits/const-trait-bounds-trait-objects.stderr +++ b/tests/ui/traits/const-traits/const-trait-bounds-trait-objects.stderr @@ -19,12 +19,34 @@ LL | const fn handle(_: &dyn const NonConst) {} | ^^^^^^^^^^^^^^ error: `[const]` is not allowed here - --> $DIR/const-trait-bounds-trait-objects.rs:17:23 + --> $DIR/const-trait-bounds-trait-objects.rs:18:23 | LL | const fn take(_: &dyn [const] NonConst) {} | ^^^^^^^ | = note: trait objects cannot have `[const]` trait bounds -error: aborting due to 4 previous errors +error: `const` can only be applied to `#[const_trait]` traits + --> $DIR/const-trait-bounds-trait-objects.rs:15:25 + | +LL | const fn handle(_: &dyn const NonConst) {} + | ^^^^^ can't be applied to `NonConst` + | +help: mark `NonConst` as `#[const_trait]` to allow it to have `const` implementations + | +LL | #[const_trait] trait NonConst {} + | ++++++++++++++ + +error: `[const]` can only be applied to `#[const_trait]` traits + --> $DIR/const-trait-bounds-trait-objects.rs:18:23 + | +LL | const fn take(_: &dyn [const] NonConst) {} + | ^^^^^^^ can't be applied to `NonConst` + | +help: mark `NonConst` as `#[const_trait]` to allow it to have `const` implementations + | +LL | #[const_trait] trait NonConst {} + | ++++++++++++++ + +error: aborting due to 6 previous errors |