bjoernager/rust
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Make gen blocks implement the Iterator trait

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This commit is contained in:
Oli Scherer 2023-10-20 22:48:37 +00:00
parent 621494382d
commit 998a816106
17 changed files with 286 additions and 7 deletions
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48
compiler/rustc_trait_selection/src/traits/project.rs
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@ -1798,7 +1798,7 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
let self_ty = selcx.infcx.shallow_resolve(obligation.predicate.self_ty());
let lang_items = selcx.tcx().lang_items();
if [lang_items.gen_trait(), lang_items.future_trait()].contains(&Some(trait_ref.def_id))
if [lang_items.gen_trait(), lang_items.future_trait(), lang_items.iterator_trait()].contains(&Some(trait_ref.def_id))
|| selcx.tcx().fn_trait_kind_from_def_id(trait_ref.def_id).is_some()
{
true
@ -2015,6 +2015,8 @@ fn confirm_select_candidate<'cx, 'tcx>(
confirm_coroutine_candidate(selcx, obligation, data)
} else if lang_items.future_trait() == Some(trait_def_id) {
confirm_future_candidate(selcx, obligation, data)
} else if lang_items.iterator_trait() == Some(trait_def_id) {
confirm_iterator_candidate(selcx, obligation, data)
} else if selcx.tcx().fn_trait_kind_from_def_id(trait_def_id).is_some() {
if obligation.predicate.self_ty().is_closure() {
confirm_closure_candidate(selcx, obligation, data)
@ -2135,6 +2137,50 @@ fn confirm_future_candidate<'cx, 'tcx>(
.with_addl_obligations(obligations)
}
fn confirm_iterator_candidate<'cx, 'tcx>(
selcx: &mut SelectionContext<'cx, 'tcx>,
obligation: &ProjectionTyObligation<'tcx>,
nested: Vec<PredicateObligation<'tcx>>,
) -> Progress<'tcx> {
let ty::Coroutine(_, args, _) =
selcx.infcx.shallow_resolve(obligation.predicate.self_ty()).kind()
else {
unreachable!()
};
let gen_sig = args.as_coroutine().poly_sig();
let Normalized { value: gen_sig, obligations } = normalize_with_depth(
selcx,
obligation.param_env,
obligation.cause.clone(),
obligation.recursion_depth + 1,
gen_sig,
);
debug!(?obligation, ?gen_sig, ?obligations, "confirm_future_candidate");
let tcx = selcx.tcx();
let iter_def_id = tcx.require_lang_item(LangItem::Iterator, None);
let predicate = super::util::iterator_trait_ref_and_outputs(
tcx,
iter_def_id,
obligation.predicate.self_ty(),
gen_sig,
)
.map_bound(|(trait_ref, yield_ty)| {
debug_assert_eq!(tcx.associated_item(obligation.predicate.def_id).name, sym::Item);
ty::ProjectionPredicate {
projection_ty: ty::AliasTy::new(tcx, obligation.predicate.def_id, trait_ref.args),
term: yield_ty.into(),
}
});
confirm_param_env_candidate(selcx, obligation, predicate, false)
.with_addl_obligations(nested)
.with_addl_obligations(obligations)
}
fn confirm_builtin_candidate<'cx, 'tcx>(
selcx: &mut SelectionContext<'cx, 'tcx>,
obligation: &ProjectionTyObligation<'tcx>,