Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly
Sign up
Appearance settings
This repository was archived by the owner on May 28, 2025. It is now read-only.

Commit 2406961

Browse files
Unrolled build for rust-lang#134367
Rollup merge of rust-lang#134367 - WaffleLapkin:trait_upcasting_as_a_treat, r=compiler-errors Stabilize `feature(trait_upcasting)` This feature was "done" for a while now, I think it's finally time to stabilize it! Stabilization report: rust-lang#134367 (comment). cc reference PR: rust-lang/reference#1622. Closes rust-lang#65991 (tracking issue), closes rust-lang#89460 (the lint is no longer future incompat). r? compiler-errors
2 parents 64e06c0 + 4915995 commit 2406961

File tree

94 files changed

+140
-479
lines changed

Some content is hidden

Large Commits have some content hidden by default. Use the searchbox below for content that may be hidden.

94 files changed

+140
-479
lines changed

‎compiler/rustc_feature/src/accepted.rs

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -400,6 +400,9 @@ declare_features! (
400400
/// Allows `#[track_caller]` to be used which provides
401401
/// accurate caller location reporting during panic (RFC 2091).
402402
(accepted, track_caller, "1.46.0", Some(47809)),
403+
/// Allows dyn upcasting trait objects via supertraits.
404+
/// Dyn upcasting is casting, e.g., `dyn Foo -> dyn Bar` where `Foo: Bar`.
405+
(accepted, trait_upcasting, "CURRENT_RUSTC_VERSION", Some(65991)),
403406
/// Allows #[repr(transparent)] on univariant enums (RFC 2645).
404407
(accepted, transparent_enums, "1.42.0", Some(60405)),
405408
/// Allows indexing tuples.

‎compiler/rustc_feature/src/unstable.rs

Lines changed: 0 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -634,9 +634,6 @@ declare_features! (
634634
(unstable, thread_local, "1.0.0", Some(29594)),
635635
/// Allows defining `trait X = A + B;` alias items.
636636
(unstable, trait_alias, "1.24.0", Some(41517)),
637-
/// Allows dyn upcasting trait objects via supertraits.
638-
/// Dyn upcasting is casting, e.g., `dyn Foo -> dyn Bar` where `Foo: Bar`.
639-
(unstable, trait_upcasting, "1.56.0", Some(65991)),
640637
/// Allows for transmuting between arrays with sizes that contain generic consts.
641638
(unstable, transmute_generic_consts, "1.70.0", Some(109929)),
642639
/// Allows #[repr(transparent)] on unions (RFC 2645).

‎compiler/rustc_hir_typeck/src/coercion.rs

Lines changed: 0 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -605,7 +605,6 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
605605
)];
606606

607607
let mut has_unsized_tuple_coercion = false;
608-
let mut has_trait_upcasting_coercion = None;
609608

610609
// Keep resolving `CoerceUnsized` and `Unsize` predicates to avoid
611610
// emitting a coercion in cases like `Foo<1ドル>` -> `Foo<2ドル>`, where
@@ -690,13 +689,6 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
690689
// these here and emit a feature error if coercion doesn't fail
691690
// due to another reason.
692691
match impl_source {
693-
traits::ImplSource::Builtin(
694-
BuiltinImplSource::TraitUpcasting { .. },
695-
_,
696-
) => {
697-
has_trait_upcasting_coercion =
698-
Some((trait_pred.self_ty(), trait_pred.trait_ref.args.type_at(1)));
699-
}
700692
traits::ImplSource::Builtin(BuiltinImplSource::TupleUnsizing, _) => {
701693
has_unsized_tuple_coercion = true;
702694
}
@@ -707,21 +699,6 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
707699
}
708700
}
709701

710-
if let Some((sub, sup)) = has_trait_upcasting_coercion
711-
&& !self.tcx().features().trait_upcasting()
712-
{
713-
// Renders better when we erase regions, since they're not really the point here.
714-
let (sub, sup) = self.tcx.erase_regions((sub, sup));
715-
let mut err = feature_err(
716-
&self.tcx.sess,
717-
sym::trait_upcasting,
718-
self.cause.span,
719-
format!("cannot cast `{sub}` to `{sup}`, trait upcasting coercion is experimental"),
720-
);
721-
err.note(format!("required when coercing `{source}` into `{target}`"));
722-
err.emit();
723-
}
724-
725702
if has_unsized_tuple_coercion && !self.tcx.features().unsized_tuple_coercion() {
726703
feature_err(
727704
&self.tcx.sess,

‎compiler/rustc_lint/src/deref_into_dyn_supertrait.rs

Lines changed: 12 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,5 @@
11
use rustc_hir::{self as hir, LangItem};
22
use rustc_middle::ty;
3-
use rustc_session::lint::FutureIncompatibilityReason;
43
use rustc_session::{declare_lint, declare_lint_pass};
54
use rustc_span::sym;
65
use rustc_trait_selection::traits::supertraits;
@@ -9,11 +8,12 @@ use crate::lints::{SupertraitAsDerefTarget, SupertraitAsDerefTargetLabel};
98
use crate::{LateContext, LateLintPass, LintContext};
109

1110
declare_lint! {
12-
/// The `deref_into_dyn_supertrait` lint is output whenever there is a use of the
13-
/// `Deref` implementation with a `dyn SuperTrait` type as `Output`.
11+
/// The `deref_into_dyn_supertrait` lint is emitted whenever there is a `Deref` implementation
12+
/// for `dyn SubTrait` with a `dyn SuperTrait` type as the `Output` type.
1413
///
15-
/// These implementations will become shadowed when the `trait_upcasting` feature is stabilized.
16-
/// The `deref` functions will no longer be called implicitly, so there might be behavior change.
14+
/// These implementations are "shadowed" by trait upcasting (stabilized since
15+
/// CURRENT_RUSTC_VERSION). The `deref` functions is no longer called implicitly, which might
16+
/// change behavior compared to previous rustc versions.
1717
///
1818
/// ### Example
1919
///
@@ -43,15 +43,14 @@ declare_lint! {
4343
///
4444
/// ### Explanation
4545
///
46-
/// The dyn upcasting coercion feature adds new coercion rules, taking priority
47-
/// over certain other coercion rules, which will cause some behavior change.
46+
/// The trait upcasting coercion added a new coercion rule, taking priority over certain other
47+
/// coercion rules, which causes some behavior change compared to older `rustc` versions.
48+
///
49+
/// `deref` can be still called explicitly, it just isn't called as part of a deref coercion
50+
/// (since trait upcasting coercion takes priority).
4851
pub DEREF_INTO_DYN_SUPERTRAIT,
49-
Warn,
50-
"`Deref` implementation usage with a supertrait trait object for output might be shadowed in the future",
51-
@future_incompatible = FutureIncompatibleInfo {
52-
reason: FutureIncompatibilityReason::FutureReleaseSemanticsChange,
53-
reference: "issue #89460 <https://github.com/rust-lang/rust/issues/89460>",
54-
};
52+
Allow,
53+
"`Deref` implementation with a supertrait trait object for output is shadowed by trait upcasting",
5554
}
5655

5756
declare_lint_pass!(DerefIntoDynSupertrait => [DEREF_INTO_DYN_SUPERTRAIT]);

‎compiler/rustc_lint/src/lib.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,7 @@
2121
2222
// tidy-alphabetical-start
2323
#![allow(internal_features)]
24+
#![cfg_attr(bootstrap, feature(trait_upcasting))]
2425
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
2526
#![doc(rust_logo)]
2627
#![feature(array_windows)]
@@ -32,7 +33,6 @@
3233
#![feature(let_chains)]
3334
#![feature(rustc_attrs)]
3435
#![feature(rustdoc_internals)]
35-
#![feature(trait_upcasting)]
3636
#![warn(unreachable_pub)]
3737
// tidy-alphabetical-end
3838

‎compiler/rustc_middle/src/lib.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -29,6 +29,7 @@
2929
#![allow(rustc::diagnostic_outside_of_impl)]
3030
#![allow(rustc::potential_query_instability)]
3131
#![allow(rustc::untranslatable_diagnostic)]
32+
#![cfg_attr(bootstrap, feature(trait_upcasting))]
3233
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
3334
#![doc(rust_logo)]
3435
#![feature(allocator_api)]
@@ -56,7 +57,6 @@
5657
#![feature(ptr_alignment_type)]
5758
#![feature(rustc_attrs)]
5859
#![feature(rustdoc_internals)]
59-
#![feature(trait_upcasting)]
6060
#![feature(trusted_len)]
6161
#![feature(try_blocks)]
6262
#![feature(try_trait_v2)]

‎compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

Lines changed: 1 addition & 62 deletions
Original file line numberDiff line numberDiff line change
@@ -12,9 +12,7 @@ use hir::LangItem;
1212
use hir::def_id::DefId;
1313
use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
1414
use rustc_hir as hir;
15-
use rustc_infer::traits::{
16-
Obligation, ObligationCause, PolyTraitObligation, PredicateObligations, SelectionError,
17-
};
15+
use rustc_infer::traits::{Obligation, PolyTraitObligation, SelectionError};
1816
use rustc_middle::ty::fast_reject::DeepRejectCtxt;
1917
use rustc_middle::ty::{self, Ty, TypeVisitableExt, TypingMode};
2018
use rustc_middle::{bug, span_bug};
@@ -23,8 +21,6 @@ use tracing::{debug, instrument, trace};
2321

2422
use super::SelectionCandidate::*;
2523
use super::{BuiltinImplConditions, SelectionCandidateSet, SelectionContext, TraitObligationStack};
26-
use crate::traits;
27-
use crate::traits::query::evaluate_obligation::InferCtxtExt;
2824
use crate::traits::util;
2925

3026
impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
@@ -904,54 +900,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
904900
})
905901
}
906902

907-
/// Temporary migration for #89190
908-
fn need_migrate_deref_output_trait_object(
909-
&mut self,
910-
ty: Ty<'tcx>,
911-
param_env: ty::ParamEnv<'tcx>,
912-
cause: &ObligationCause<'tcx>,
913-
) -> Option<ty::PolyExistentialTraitRef<'tcx>> {
914-
// Don't drop any candidates in intercrate mode, as it's incomplete.
915-
// (Not that it matters, since `Unsize` is not a stable trait.)
916-
//
917-
// FIXME(@lcnr): This should probably only trigger during analysis,
918-
// disabling candidates during codegen is also questionable.
919-
if let TypingMode::Coherence = self.infcx.typing_mode() {
920-
return None;
921-
}
922-
923-
let tcx = self.tcx();
924-
if tcx.features().trait_upcasting() {
925-
return None;
926-
}
927-
928-
// <ty as Deref>
929-
let trait_ref = ty::TraitRef::new(tcx, tcx.lang_items().deref_trait()?, [ty]);
930-
931-
let obligation =
932-
traits::Obligation::new(tcx, cause.clone(), param_env, ty::Binder::dummy(trait_ref));
933-
if !self.infcx.predicate_may_hold(&obligation) {
934-
return None;
935-
}
936-
937-
self.infcx.probe(|_| {
938-
let ty = traits::normalize_projection_ty(
939-
self,
940-
param_env,
941-
ty::AliasTy::new_from_args(tcx, tcx.lang_items().deref_target()?, trait_ref.args),
942-
cause.clone(),
943-
0,
944-
// We're *intentionally* throwing these away,
945-
// since we don't actually use them.
946-
&mut PredicateObligations::new(),
947-
)
948-
.as_type()
949-
.unwrap();
950-
951-
if let ty::Dynamic(data, ..) = ty.kind() { data.principal() } else { None }
952-
})
953-
}
954-
955903
/// Searches for unsizing that might apply to `obligation`.
956904
fn assemble_candidates_for_unsizing(
957905
&mut self,
@@ -1019,15 +967,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
1019967
let principal_a = a_data.principal().unwrap();
1020968
let target_trait_did = principal_def_id_b.unwrap();
1021969
let source_trait_ref = principal_a.with_self_ty(self.tcx(), source);
1022-
if let Some(deref_trait_ref) = self.need_migrate_deref_output_trait_object(
1023-
source,
1024-
obligation.param_env,
1025-
&obligation.cause,
1026-
) {
1027-
if deref_trait_ref.def_id() == target_trait_did {
1028-
return;
1029-
}
1030-
}
1031970

1032971
for (idx, upcast_trait_ref) in
1033972
util::supertraits(self.tcx(), source_trait_ref).enumerate()

‎compiler/rustc_type_ir/src/solve/mod.rs

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -179,9 +179,7 @@ pub enum BuiltinImplSource {
179179
Object(usize),
180180
/// A built-in implementation of `Upcast` for trait objects to other trait objects.
181181
///
182-
/// This can be removed when `feature(dyn_upcasting)` is stabilized, since we only
183-
/// use it to detect when upcasting traits in hir typeck. The index is only used
184-
/// for winnowing.
182+
/// The index is only used for winnowing.
185183
TraitUpcasting(usize),
186184
/// Unsizing a tuple like `(A, B, ..., X)` to `(A, B, ..., Y)` if `X` unsizes to `Y`.
187185
///

‎library/coretests/tests/lib.rs

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -81,7 +81,6 @@
8181
#![feature(strict_provenance_atomic_ptr)]
8282
#![feature(strict_provenance_lints)]
8383
#![feature(test)]
84-
#![feature(trait_upcasting)]
8584
#![feature(trusted_len)]
8685
#![feature(trusted_random_access)]
8786
#![feature(try_blocks)]

‎src/doc/unstable-book/src/language-features/trait-upcasting.md

Lines changed: 0 additions & 26 deletions
This file was deleted.

0 commit comments

Comments
(0)

AltStyle によって変換されたページ (->オリジナル) /