bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #121676 - Bryanskiy:polarity, r=petrochenkov

Browse source 
Support ?Trait bounds in supertraits and dyn Trait under a feature gate

This patch allows `maybe` polarity bounds under a feature gate. The only language change here is that corresponding hard errors are replaced by feature gates. Example:
```rust
#![feature(allow_maybe_polarity)]
...
trait Trait1 : ?Trait { ... } // ok
fn foo(_: Box<(dyn Trait2 + ?Trait)>) {} // ok
fn bar<T: ?Sized + ?Trait>(_: &T) {} // ok
```
Maybe bounds still don't do anything (except for `Sized` trait), however this patch will allow us to [experiment with default auto traits](https://github.com/rust-lang/rust/pull/120706#issuecomment-1934006762).

This is a part of the [MCP: Low level components for async drop](https://github.com/rust-lang/compiler-team/issues/727)
This commit is contained in:
bors 2024-07-26 20:14:16 +00:00
commit 7c2012d0ec
36 changed files with 364 additions and 83 deletions
Download patch file Download diff file Expand all files Collapse all files

6
compiler/rustc_hir/src/hir.rs
View file

@ -2832,7 +2832,11 @@ pub enum TyKind<'hir> {
OpaqueDef(ItemId, &'hir [GenericArg<'hir>], bool),
/// A trait object type `Bound1 + Bound2 + Bound3`
/// where `Bound` is a trait or a lifetime.
TraitObject(&'hir [PolyTraitRef<'hir>], &'hir Lifetime, TraitObjectSyntax),
TraitObject(
&'hir [(PolyTraitRef<'hir>, TraitBoundModifier)],
&'hir Lifetime,
TraitObjectSyntax,
),
/// Unused for now.
Typeof(&'hir AnonConst),
/// `TyKind::Infer` means the type should be inferred instead of it having been

4
compiler/rustc_hir/src/intravisit.rs
View file

@ -902,7 +902,9 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) -> V::Resul
try_visit!(visitor.visit_array_length(length));
}
TyKind::TraitObject(bounds, ref lifetime, _syntax) => {
walk_list!(visitor, visit_poly_trait_ref, bounds);
for (bound, _modifier) in bounds {
try_visit!(visitor.visit_poly_trait_ref(bound));
}
try_visit!(visitor.visit_lifetime(lifetime));
}
TyKind::Typeof(ref expression) => try_visit!(visitor.visit_anon_const(expression)),