Backport new sized-hierarchy trait bounds in old ways

This commit is contained in:
Shoyu Vanilla 2025-06-25 23:23:11 +09:00
parent d3e6dcd3ca
commit 953e9d1c36
5 changed files with 78 additions and 24 deletions

View file

@ -308,6 +308,8 @@ impl LangItem {
language_item_table! {
// Variant name, Name, Getter method name, Target Generic requirements;
Sized, sym::sized, sized_trait, Target::Trait, GenericRequirement::Exact(0);
MetaSized, sym::meta_sized, sized_trait, Target::Trait, GenericRequirement::Exact(0);
PointeeSized, sym::pointee_sized, sized_trait, Target::Trait, GenericRequirement::Exact(0);
Unsize, sym::unsize, unsize_trait, Target::Trait, GenericRequirement::Minimum(1);
/// Trait injected by `#[derive(PartialEq)]`, (i.e. "Partial EQ").
StructuralPeq, sym::structural_peq, structural_peq_trait, Target::Trait, GenericRequirement::None;

View file

@ -581,11 +581,28 @@ impl<'a> TyLoweringContext<'a> {
match bound {
&TypeBound::Path(path, TraitBoundModifier::None) | &TypeBound::ForLifetime(_, path) => {
// FIXME Don't silently drop the hrtb lifetimes here
if let Some((trait_ref, ctx)) = self.lower_trait_ref_from_path(path, self_ty) {
if !ignore_bindings {
assoc_bounds = ctx.assoc_type_bindings_from_type_bound(trait_ref.clone());
if let Some((trait_ref, mut ctx)) =
self.lower_trait_ref_from_path(path, self_ty.clone())
{
// FIXME(sized-hierarchy): Remove this bound modifications once we have implemented
// sized-hierarchy correctly.
let meta_sized = LangItem::MetaSized
.resolve_trait(ctx.ty_ctx().db, ctx.ty_ctx().resolver.krate());
let pointee_sized = LangItem::PointeeSized
.resolve_trait(ctx.ty_ctx().db, ctx.ty_ctx().resolver.krate());
if meta_sized.is_some_and(|it| it == trait_ref.hir_trait_id()) {
// Ignore this bound
} else if pointee_sized.is_some_and(|it| it == trait_ref.hir_trait_id()) {
// Regard this as `?Sized` bound
ctx.ty_ctx().unsized_types.insert(self_ty);
} else {
if !ignore_bindings {
assoc_bounds =
ctx.assoc_type_bindings_from_type_bound(trait_ref.clone());
}
clause =
Some(crate::wrap_empty_binders(WhereClause::Implemented(trait_ref)));
}
clause = Some(crate::wrap_empty_binders(WhereClause::Implemented(trait_ref)));
}
}
&TypeBound::Path(path, TraitBoundModifier::Maybe) => {
@ -945,8 +962,32 @@ pub(crate) fn generic_predicates_for_param_query(
| WherePredicate::TypeBound { target, bound, .. } => {
let invalid_target = { ctx.lower_ty_only_param(*target) != Some(param_id) };
if invalid_target {
// If this is filtered out without lowering, `?Sized` is not gathered into `ctx.unsized_types`
if let TypeBound::Path(_, TraitBoundModifier::Maybe) = bound {
// FIXME(sized-hierarchy): Revisit and adjust this properly once we have implemented
// sized-hierarchy correctly.
// If this is filtered out without lowering, `?Sized` or `PointeeSized` is not gathered into
// `ctx.unsized_types`
let lower = || -> bool {
match bound {
TypeBound::Path(_, TraitBoundModifier::Maybe) => true,
TypeBound::Path(path, _) | TypeBound::ForLifetime(_, path) => {
let TypeRef::Path(path) = &ctx.store[path.type_ref()] else {
return false;
};
let Some(pointee_sized) =
LangItem::PointeeSized.resolve_trait(ctx.db, ctx.resolver.krate())
else {
return false;
};
// Lower the path directly with `Resolver` instead of PathLoweringContext`
// to prevent diagnostics duplications.
ctx.resolver.resolve_path_in_type_ns_fully(ctx.db, path).is_some_and(
|it| matches!(it, TypeNs::TraitId(tr) if tr == pointee_sized),
)
}
_ => false,
}
}();
if lower {
ctx.lower_where_predicate(pred, true).for_each(drop);
}
return false;

View file

@ -143,7 +143,7 @@ fn foo<T>() {}
file_id: FileId(
1,
),
range: 135..140,
range: 446..451,
},
),
),

View file

@ -438,6 +438,8 @@ define_symbols! {
shr,
simd,
sized,
meta_sized,
pointee_sized,
skip,
slice_len_fn,
Some,

View file

@ -26,7 +26,7 @@
//! deref: sized
//! derive:
//! discriminant:
//! drop:
//! drop: sized
//! env: option
//! eq: sized
//! error: fmt
@ -37,7 +37,7 @@
//! future: pin
//! coroutine: pin
//! dispatch_from_dyn: unsize, pin
//! hash:
//! hash: sized
//! include:
//! index: sized
//! infallible:
@ -80,24 +80,18 @@ pub mod marker {
#[lang = "pointee_sized"]
#[fundamental]
#[rustc_specialization_trait]
#[rustc_deny_explicit_impl]
#[rustc_do_not_implement_via_object]
#[rustc_coinductive]
pub trait PointeeSized {}
#[lang = "meta_sized"]
#[fundamental]
#[rustc_specialization_trait]
#[rustc_deny_explicit_impl]
#[rustc_do_not_implement_via_object]
#[rustc_coinductive]
pub trait MetaSized: PointeeSized {}
#[lang = "sized"]
#[fundamental]
#[rustc_specialization_trait]
#[rustc_deny_explicit_impl]
#[rustc_do_not_implement_via_object]
#[rustc_coinductive]
pub trait Sized: MetaSized {}
// endregion:sized
@ -139,7 +133,7 @@ pub mod marker {
// endregion:derive
mod copy_impls {
use super::Copy;
use super::{Copy, PointeeSized};
macro_rules! impl_copy {
($($t:ty)*) => {
@ -225,6 +219,8 @@ pub mod default {
// region:hash
pub mod hash {
use crate::marker::PointeeSized;
pub trait Hasher {}
pub trait Hash: PointeeSized {
@ -240,6 +236,7 @@ pub mod hash {
// region:cell
pub mod cell {
use crate::marker::PointeeSized;
use crate::mem;
#[lang = "unsafe_cell"]
@ -376,7 +373,7 @@ pub mod convert {
// endregion:from
// region:as_ref
pub trait AsRef<T: PointeeSized>: PointeeSized {
pub trait AsRef<T: crate::marker::PointeeSized>: crate::marker::PointeeSized {
fn as_ref(&self) -> &T;
}
// endregion:as_ref
@ -387,6 +384,8 @@ pub mod convert {
pub mod mem {
// region:manually_drop
use crate::marker::PointeeSized;
#[lang = "manually_drop"]
#[repr(transparent)]
pub struct ManuallyDrop<T: PointeeSized> {
@ -447,7 +446,7 @@ pub mod mem {
pub mod ptr {
// region:drop
#[lang = "drop_in_place"]
pub unsafe fn drop_in_place<T: PointeeSized>(to_drop: *mut T) {
pub unsafe fn drop_in_place<T: crate::marker::PointeeSized>(to_drop: *mut T) {
unsafe { drop_in_place(to_drop) }
}
pub const unsafe fn read<T>(src: *const T) -> T {
@ -463,7 +462,7 @@ pub mod ptr {
// region:pointee
#[lang = "pointee_trait"]
#[rustc_deny_explicit_impl(implement_via_object = false)]
pub trait Pointee: PointeeSized {
pub trait Pointee: crate::marker::PointeeSized {
#[lang = "metadata_type"]
type Metadata: Copy + Send + Sync + Ord + Hash + Unpin;
}
@ -471,12 +470,14 @@ pub mod ptr {
// region:non_null
#[rustc_layout_scalar_valid_range_start(1)]
#[rustc_nonnull_optimization_guaranteed]
pub struct NonNull<T: PointeeSized> {
pub struct NonNull<T: crate::marker::PointeeSized> {
pointer: *const T,
}
// region:coerce_unsized
impl<T: PointeeSized, U: PointeeSized> crate::ops::CoerceUnsized<NonNull<U>> for NonNull<T> where
T: crate::marker::Unsize<U>
impl<T: crate::marker::PointeeSized, U: crate::marker::PointeeSized>
crate::ops::CoerceUnsized<NonNull<U>> for NonNull<T>
where
T: crate::marker::Unsize<U>,
{
}
// endregion:coerce_unsized
@ -497,7 +498,7 @@ pub mod ptr {
pub mod ops {
// region:coerce_unsized
mod unsize {
use crate::marker::Unsize;
use crate::marker::{PointeeSized, Unsize};
#[lang = "coerce_unsized"]
pub trait CoerceUnsized<T> {}
@ -519,6 +520,8 @@ pub mod ops {
// region:deref
mod deref {
use crate::marker::PointeeSized;
#[lang = "deref"]
pub trait Deref: PointeeSized {
#[lang = "deref_target"]
@ -1025,7 +1028,7 @@ pub mod ops {
// region:dispatch_from_dyn
mod dispatch_from_dyn {
use crate::marker::Unsize;
use crate::marker::{PointeeSized, Unsize};
#[lang = "dispatch_from_dyn"]
pub trait DispatchFromDyn<T> {}
@ -1044,6 +1047,8 @@ pub mod ops {
// region:eq
pub mod cmp {
use crate::marker::PointeeSized;
#[lang = "eq"]
pub trait PartialEq<Rhs: PointeeSized = Self>: PointeeSized {
fn eq(&self, other: &Rhs) -> bool;
@ -1090,6 +1095,8 @@ pub mod cmp {
// region:fmt
pub mod fmt {
use crate::marker::PointeeSized;
pub struct Error;
pub type Result = crate::result::Result<(), Error>;
pub struct Formatter<'a>;
@ -1531,6 +1538,8 @@ pub mod iter {
mod traits {
mod iterator {
use crate::marker::PointeeSized;
#[doc(notable_trait)]
#[lang = "iterator"]
pub trait Iterator {