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Remove dyn_compatible_for_dispatch

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This commit is contained in:
Michael Goulet 2025-02-04 02:37:13 +00:00
parent 617aad8c2e
commit f3d31f77e4
58 changed files with 524 additions and 899 deletions
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8
compiler/rustc_trait_selection/src/traits/dyn_compatibility.rs
View file

@ -538,10 +538,10 @@ fn receiver_for_self_ty<'tcx>(
/// a pointer.
///
/// In practice, we cannot use `dyn Trait` explicitly in the obligation because it would result in
/// a new check that `Trait` is dyn-compatible, creating a cycle (until dyn_compatible_for_dispatch
/// is stabilized, see tracking issue <https://github.com/rust-lang/rust/issues/43561>).
/// Instead, we fudge a little by introducing a new type parameter `U` such that
/// a new check that `Trait` is dyn-compatible, creating a cycle.
/// Instead, we emulate a placeholder by introducing a new type parameter `U` such that
/// `Self: Unsize<U>` and `U: Trait + ?Sized`, and use `U` in place of `dyn Trait`.
///
/// Written as a chalk-style query:
/// ```ignore (not-rust)
/// forall (U: Trait + ?Sized) {
@ -572,8 +572,6 @@ fn receiver_is_dispatchable<'tcx>(
// the type `U` in the query
// use a bogus type parameter to mimic a forall(U) query using u32::MAX for now.
// FIXME(mikeyhew) this is a total hack. Once dyn_compatible_for_dispatch is stabilized, we can
// replace this with `dyn Trait`
let unsized_self_ty: Ty<'tcx> =
Ty::new_param(tcx, u32::MAX, rustc_span::sym::RustaceansAreAwesome);

8
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
View file

@ -859,13 +859,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
if let Some(principal) = data.principal() {
if !self.infcx.tcx.features().dyn_compatible_for_dispatch() {
principal.with_self_ty(self.tcx(), self_ty)
} else if self.tcx().is_dyn_compatible(principal.def_id()) {
principal.with_self_ty(self.tcx(), self_ty)
} else {
return;
}
principal.with_self_ty(self.tcx(), self_ty)
} else {
// Only auto trait bounds exist.
return;

21
compiler/rustc_trait_selection/src/traits/wf.rs
View file

@ -904,19 +904,14 @@ impl<'a, 'tcx> TypeVisitor<TyCtxt<'tcx>> for WfPredicates<'a, 'tcx> {
// FIXME(#27579) RFC also considers adding trait
// obligations that don't refer to Self and
// checking those
let defer_to_coercion = tcx.features().dyn_compatible_for_dispatch();
if !defer_to_coercion {
if let Some(principal) = data.principal_def_id() {
self.out.push(traits::Obligation::with_depth(
tcx,
self.cause(ObligationCauseCode::WellFormed(None)),
self.recursion_depth,
self.param_env,
ty::Binder::dummy(ty::PredicateKind::DynCompatible(principal)),
));
}
if let Some(principal) = data.principal_def_id() {
self.out.push(traits::Obligation::with_depth(
tcx,
self.cause(ObligationCauseCode::WellFormed(None)),
self.recursion_depth,
self.param_env,
ty::Binder::dummy(ty::PredicateKind::DynCompatible(principal)),
));
}
}