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Rollup merge of #122829 - ShoyuVanilla:gen-block-impl-fused-iter, r=compiler-errors

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Implement `FusedIterator` for `gen` block

cc #117078
This commit is contained in:
Matthias Krüger
2024-03-22 01:07:31 +01:00
committed by GitHub
parent 08ac38b661 ae4c5c891e
commit 1757cb5871
10 changed files with 105 additions and 7 deletions
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33
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
View File

@@ -118,6 +118,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
self.assemble_future_candidates(obligation, &mut candidates);
} else if lang_items.iterator_trait() == Some(def_id) {
self.assemble_iterator_candidates(obligation, &mut candidates);
} else if lang_items.fused_iterator_trait() == Some(def_id) {
self.assemble_fused_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) {
@@ -302,14 +304,31 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
candidates: &mut SelectionCandidateSet<'tcx>,
) {
let self_ty = obligation.self_ty().skip_binder();
if let ty::Coroutine(did, ..) = self_ty.kind() {
// gen constructs get lowered to a special kind of coroutine that
// should directly `impl Iterator`.
if self.tcx().coroutine_is_gen(*did) {
debug!(?self_ty, ?obligation, "assemble_iterator_candidates",);
// gen constructs get lowered to a special kind of coroutine that
// should directly `impl Iterator`.
if let ty::Coroutine(did, ..) = self_ty.kind()
&& self.tcx().coroutine_is_gen(*did)
{
debug!(?self_ty, ?obligation, "assemble_iterator_candidates",);
candidates.vec.push(IteratorCandidate);
}
candidates.vec.push(IteratorCandidate);
}
}
fn assemble_fused_iterator_candidates(
&mut self,
obligation: &PolyTraitObligation<'tcx>,
candidates: &mut SelectionCandidateSet<'tcx>,
) {
let self_ty = obligation.self_ty().skip_binder();
// gen constructs get lowered to a special kind of coroutine that
// should directly `impl FusedIterator`.
if let ty::Coroutine(did, ..) = self_ty.kind()
&& self.tcx().coroutine_is_gen(*did)
{
debug!(?self_ty, ?obligation, "assemble_fused_iterator_candidates",);
candidates.vec.push(BuiltinCandidate { has_nested: false });
}
}

2
compiler/rustc_trait_selection/src/traits/select/confirmation.rs
View File

@@ -267,6 +267,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
self.copy_clone_conditions(obligation)
} else if Some(trait_def) == lang_items.clone_trait() {
self.copy_clone_conditions(obligation)
} else if Some(trait_def) == lang_items.fused_iterator_trait() {
self.fused_iterator_conditions(obligation)
} else {
bug!("unexpected builtin trait {:?}", trait_def)
};

14
compiler/rustc_trait_selection/src/traits/select/mod.rs
View File

@@ -2259,6 +2259,20 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
}
}
fn fused_iterator_conditions(
&mut self,
obligation: &PolyTraitObligation<'tcx>,
) -> BuiltinImplConditions<'tcx> {
let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder());
if let ty::Coroutine(did, ..) = *self_ty.kind()
&& self.tcx().coroutine_is_gen(did)
{
BuiltinImplConditions::Where(ty::Binder::dummy(Vec::new()))
} else {
BuiltinImplConditions::None
}
}
/// For default impls, we need to break apart a type into its
/// "constituent types" -- meaning, the types that it contains.
///