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Rollup merge of #136968 - oli-obk:bye-bye, r=compiler-errors

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Turn order dependent trait objects future incompat warning into a hard error

fixes #56484

r? ``@ghost``

will FCP when we have a crater result
This commit is contained in:
Matthias Krüger 2025-03-09 10:34:47 +01:00 • committed by GitHub
commit 5a46f82d7e
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13 changed files with 38 additions and 330 deletions
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58
compiler/rustc_ty_utils/src/ty.rs
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@ -6,13 +6,11 @@ use rustc_index::bit_set::DenseBitSet;
use rustc_middle::bug;
use rustc_middle::query::Providers;
use rustc_middle::ty::fold::fold_regions;
use rustc_middle::ty::{
self, EarlyBinder, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, Upcast,
};
use rustc_middle::ty::{self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, Upcast};
use rustc_span::DUMMY_SP;
use rustc_span::def_id::{CRATE_DEF_ID, DefId, LocalDefId};
use rustc_trait_selection::traits;
use tracing::{debug, instrument};
use tracing::instrument;
#[instrument(level = "debug", skip(tcx), ret)]
fn sized_constraint_for_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'tcx>> {
@ -260,57 +258,6 @@ fn param_env_normalized_for_post_analysis(tcx: TyCtxt<'_>, def_id: DefId) -> ty:
typing_env.with_post_analysis_normalized(tcx).param_env
}
/// If the given trait impl enables exploiting the former order dependence of trait objects,
/// returns its self type; otherwise, returns `None`.
///
/// See [`ty::ImplOverlapKind::FutureCompatOrderDepTraitObjects`] for more details.
#[instrument(level = "debug", skip(tcx))]
fn self_ty_of_trait_impl_enabling_order_dep_trait_object_hack(
tcx: TyCtxt<'_>,
def_id: DefId,
) -> Option<EarlyBinder<'_, Ty<'_>>> {
let impl_ =
tcx.impl_trait_header(def_id).unwrap_or_else(|| bug!("called on inherent impl {def_id:?}"));
let trait_ref = impl_.trait_ref.skip_binder();
debug!(?trait_ref);
let is_marker_like = impl_.polarity == ty::ImplPolarity::Positive
&& tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
// Check whether these impls would be ok for a marker trait.
if !is_marker_like {
debug!("not marker-like!");
return None;
}
// impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
if trait_ref.args.len() != 1 {
debug!("impl has args!");
return None;
}
let predicates = tcx.predicates_of(def_id);
if predicates.parent.is_some() || !predicates.predicates.is_empty() {
debug!(?predicates, "impl has predicates!");
return None;
}
let self_ty = trait_ref.self_ty();
let self_ty_matches = match self_ty.kind() {
ty::Dynamic(data, re, _) if re.is_static() => data.principal().is_none(),
_ => false,
};
if self_ty_matches {
debug!("MATCHES!");
Some(EarlyBinder::bind(self_ty))
} else {
debug!("non-matching self type");
None
}
}
/// Check if a function is async.
fn asyncness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Asyncness {
let node = tcx.hir_node_by_def_id(def_id);
@ -370,7 +317,6 @@ pub(crate) fn provide(providers: &mut Providers) {
adt_sized_constraint,
param_env,
param_env_normalized_for_post_analysis,
self_ty_of_trait_impl_enabling_order_dep_trait_object_hack,
defaultness,
unsizing_params_for_adt,
..*providers