bjoernager/rust
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Teach typeck/borrowck/solvers how to deal with async closures

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This commit is contained in:
Michael Goulet 2024-01-24 22:27:25 +00:00
parent c567eddec2
commit a82bae2172
35 changed files with 1221 additions and 66 deletions
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46
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
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@ -117,9 +117,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
self.assemble_iterator_candidates(obligation, &mut candidates);
} else if lang_items.async_iterator_trait() == Some(def_id) {
self.assemble_async_iterator_candidates(obligation, &mut candidates);
} else if lang_items.async_fn_kind_helper() == Some(def_id) {
self.assemble_async_fn_kind_helper_candidates(obligation, &mut candidates);
}
self.assemble_closure_candidates(obligation, &mut candidates);
self.assemble_async_closure_candidates(obligation, &mut candidates);
self.assemble_fn_pointer_candidates(obligation, &mut candidates);
self.assemble_candidates_from_impls(obligation, &mut candidates);
self.assemble_candidates_from_object_ty(obligation, &mut candidates);
@ -335,6 +338,49 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
}
fn assemble_async_closure_candidates(
&mut self,
obligation: &PolyTraitObligation<'tcx>,
candidates: &mut SelectionCandidateSet<'tcx>,
) {
let Some(goal_kind) =
self.tcx().async_fn_trait_kind_from_def_id(obligation.predicate.def_id())
else {
return;
};
match *obligation.self_ty().skip_binder().kind() {
ty::CoroutineClosure(_, args) => {
if let Some(closure_kind) =
args.as_coroutine_closure().kind_ty().to_opt_closure_kind()
&& !closure_kind.extends(goal_kind)
{
return;
}
candidates.vec.push(AsyncClosureCandidate);
}
ty::Infer(ty::TyVar(_)) => {
candidates.ambiguous = true;
}
_ => {}
}
}
fn assemble_async_fn_kind_helper_candidates(
&mut self,
obligation: &PolyTraitObligation<'tcx>,
candidates: &mut SelectionCandidateSet<'tcx>,
) {
if let Some(closure_kind) = obligation.self_ty().skip_binder().to_opt_closure_kind()
&& let Some(goal_kind) =
obligation.predicate.skip_binder().trait_ref.args.type_at(1).to_opt_closure_kind()
{
if closure_kind.extends(goal_kind) {
candidates.vec.push(AsyncFnKindHelperCandidate);
}
}
}
/// Implements one of the `Fn()` family for a fn pointer.
fn assemble_fn_pointer_candidates(
&mut self,