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Don't install default opaque projection predicates in RPITIT associated type's param-env

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This commit is contained in:
Michael Goulet 2023-03-16 01:11:04 +00:00
parent 0949da8f4e
commit ff7c3b854d
12 changed files with 78 additions and 21 deletions
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28
compiler/rustc_hir_analysis/src/check/wfcheck.rs
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@ -1545,21 +1545,27 @@ fn check_return_position_impl_trait_in_trait_bounds<'tcx>(
if let Some(assoc_item) = tcx.opt_associated_item(fn_def_id.to_def_id())
&& assoc_item.container == ty::AssocItemContainer::TraitContainer
{
// FIXME(-Zlower-impl-trait-in-trait-to-assoc-ty): Even with the new lowering
// strategy, we can't just call `check_associated_item` on the new RPITITs,
// because tests like `tests/ui/async-await/in-trait/implied-bounds.rs` will fail.
// That's because we need to check that the bounds of the RPITIT hold using
// the special substs that we create during opaque type lowering, otherwise we're
// getting a bunch of early bound and free regions mixed up... Haven't looked too
// deep into this, though.
for arg in fn_output.walk() {
if let ty::GenericArgKind::Type(ty) = arg.unpack()
&& let ty::Alias(ty::Opaque, proj) = ty.kind()
// FIXME(-Zlower-impl-trait-in-trait-to-assoc-ty) we should just check
// `tcx.def_kind(proj.def_id) == DefKind::ImplTraitPlaceholder`. Right now
// `check_associated_type_bounds` is not called for RPITITs synthesized as
// associated types. See `check_mod_type_wf` to see how synthesized associated
// types are missed due to iterating over HIR.
&& tcx.is_impl_trait_in_trait(proj.def_id)
&& tcx.impl_trait_in_trait_parent_fn(proj.def_id) == fn_def_id.to_def_id()
// RPITITs are always eagerly normalized into opaques, so always look for an
// opaque here.
&& let ty::Alias(ty::Opaque, opaque_ty) = ty.kind()
&& let Some(opaque_def_id) = opaque_ty.def_id.as_local()
&& let opaque = tcx.hir().expect_item(opaque_def_id).expect_opaque_ty()
&& let hir::OpaqueTyOrigin::FnReturn(source) | hir::OpaqueTyOrigin::AsyncFn(source) = opaque.origin
&& source == fn_def_id
{
let span = tcx.def_span(proj.def_id);
let bounds = wfcx.tcx().explicit_item_bounds(proj.def_id);
let span = tcx.def_span(opaque_ty.def_id);
let bounds = wfcx.tcx().explicit_item_bounds(opaque_ty.def_id);
let wf_obligations = bounds.iter().flat_map(|&(bound, bound_span)| {
let bound = ty::EarlyBinder(bound).subst(tcx, proj.substs);
let bound = ty::EarlyBinder(bound).subst(tcx, opaque_ty.substs);
let normalized_bound = wfcx.normalize(span, None, bound);
traits::wf::predicate_obligations(
wfcx.infcx,