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Add simple async drop glue generation

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Explainer: https://zetanumbers.github.io/book/async-drop-design.html

https://github.com/rust-lang/rust/pull/121801
This commit is contained in:
zetanumbers 2024-02-13 12:31:41 +03:00 • committed by Daria Sukhonina
parent 1dea922ea6
commit 24a24ec6ba
40 changed files with 1921 additions and 20 deletions
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7
compiler/rustc_trait_selection/src/solve/assembly/mod.rs
View file

@ -240,6 +240,11 @@ pub(super) trait GoalKind<'tcx>:
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
fn consider_builtin_async_destruct_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx>;
fn consider_builtin_destruct_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
@ -520,6 +525,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
G::consider_builtin_coroutine_candidate(self, goal)
} else if lang_items.discriminant_kind_trait() == Some(trait_def_id) {
G::consider_builtin_discriminant_kind_candidate(self, goal)
} else if lang_items.async_destruct_trait() == Some(trait_def_id) {
G::consider_builtin_async_destruct_candidate(self, goal)
} else if lang_items.destruct_trait() == Some(trait_def_id) {
G::consider_builtin_destruct_candidate(self, goal)
} else if lang_items.transmute_trait() == Some(trait_def_id) {

53
compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs
View file

@ -814,6 +814,59 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> {
})
}
fn consider_builtin_async_destruct_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx> {
let self_ty = goal.predicate.self_ty();
let discriminant_ty = match *self_ty.kind() {
ty::Bool
| ty::Char
| ty::Int(..)
| ty::Uint(..)
| ty::Float(..)
| ty::Array(..)
| ty::RawPtr(..)
| ty::Ref(..)
| ty::FnDef(..)
| ty::FnPtr(..)
| ty::Closure(..)
| ty::CoroutineClosure(..)
| ty::Infer(ty::IntVar(..) | ty::FloatVar(..))
| ty::Coroutine(..)
| ty::CoroutineWitness(..)
| ty::Pat(..)
| ty::Never
| ty::Adt(_, _)
| ty::Str
| ty::Slice(_)
| ty::Dynamic(_, _, _)
| ty::Tuple(_)
| ty::Error(_) => self_ty.async_destructor_ty(ecx.tcx(), goal.param_env),
// We do not call `Ty::discriminant_ty` on alias, param, or placeholder
// types, which return `<self_ty as DiscriminantKind>::Discriminant`
// (or ICE in the case of placeholders). Projecting a type to itself
// is never really productive.
ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => {
return Err(NoSolution);
}
ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_))
| ty::Foreign(..)
| ty::Bound(..) => bug!(
"unexpected self ty `{:?}` when normalizing `<T as AsyncDestruct>::AsyncDestructor`",
goal.predicate.self_ty()
),
};
ecx.probe_misc_candidate("builtin async destruct").enter(|ecx| {
ecx.eq(goal.param_env, goal.predicate.term, discriminant_ty.into())
.expect("expected goal term to be fully unconstrained");
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
})
}
fn consider_builtin_destruct_candidate(
_ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,

12
compiler/rustc_trait_selection/src/solve/trait_goals.rs
View file

@ -544,6 +544,18 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
}
fn consider_builtin_async_destruct_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx> {
if goal.predicate.polarity != ty::PredicatePolarity::Positive {
return Err(NoSolution);
}
// `AsyncDestruct` is automatically implemented for every type.
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
}
fn consider_builtin_destruct_candidate(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,

43
compiler/rustc_trait_selection/src/traits/project.rs
View file

@ -1074,6 +1074,42 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
| ty::Infer(..)
| ty::Error(_) => false,
}
} else if lang_items.async_destruct_trait() == Some(trait_ref.def_id) {
match self_ty.kind() {
ty::Bool
| ty::Char
| ty::Int(_)
| ty::Uint(_)
| ty::Float(_)
| ty::Adt(..)
| ty::Str
| ty::Array(..)
| ty::Slice(_)
| ty::RawPtr(..)
| ty::Ref(..)
| ty::FnDef(..)
| ty::FnPtr(..)
| ty::Dynamic(..)
| ty::Closure(..)
| ty::CoroutineClosure(..)
| ty::Coroutine(..)
| ty::CoroutineWitness(..)
| ty::Pat(..)
| ty::Never
| ty::Tuple(..)
| ty::Infer(ty::InferTy::IntVar(_) | ty::InferTy::FloatVar(..)) => true,
// type parameters, opaques, and unnormalized projections don't have
// a known discriminant and may need to be normalized further or rely
// on param env for async destructor projections
ty::Param(_)
| ty::Foreign(_)
| ty::Alias(..)
| ty::Bound(..)
| ty::Placeholder(..)
| ty::Infer(..)
| ty::Error(_) => false,
}
} else if lang_items.pointee_trait() == Some(trait_ref.def_id) {
let tail = selcx.tcx().struct_tail_with_normalize(
self_ty,
@ -1488,15 +1524,20 @@ fn confirm_builtin_candidate<'cx, 'tcx>(
) -> Progress<'tcx> {
let tcx = selcx.tcx();
let self_ty = obligation.predicate.self_ty();
let args = tcx.mk_args(&[self_ty.into()]);
let lang_items = tcx.lang_items();
let item_def_id = obligation.predicate.def_id;
let trait_def_id = tcx.trait_of_item(item_def_id).unwrap();
let args = tcx.mk_args(&[self_ty.into()]);
let (term, obligations) = if lang_items.discriminant_kind_trait() == Some(trait_def_id) {
let discriminant_def_id = tcx.require_lang_item(LangItem::Discriminant, None);
assert_eq!(discriminant_def_id, item_def_id);
(self_ty.discriminant_ty(tcx).into(), Vec::new())
} else if lang_items.async_destruct_trait() == Some(trait_def_id) {
let destructor_def_id = tcx.associated_item_def_ids(trait_def_id)[0];
assert_eq!(destructor_def_id, item_def_id);
(self_ty.async_destructor_ty(tcx, obligation.param_env).into(), Vec::new())
} else if lang_items.pointee_trait() == Some(trait_def_id) {
let metadata_def_id = tcx.require_lang_item(LangItem::Metadata, None);
assert_eq!(metadata_def_id, item_def_id);

3
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
View file

@ -81,6 +81,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
} else if lang_items.discriminant_kind_trait() == Some(def_id) {
// `DiscriminantKind` is automatically implemented for every type.
candidates.vec.push(BuiltinCandidate { has_nested: false });
} else if lang_items.async_destruct_trait() == Some(def_id) {
// `AsyncDestruct` is automatically implemented for every type.
candidates.vec.push(BuiltinCandidate { has_nested: false });
} else if lang_items.pointee_trait() == Some(def_id) {
// `Pointee` is automatically implemented for every type.
candidates.vec.push(BuiltinCandidate { has_nested: false });