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Rollup merge of #109198 - compiler-errors:new-rpitit-default-body, r=spastorino

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Install projection from RPITIT to default trait method opaque correctly

1. For new lowering strategy `-Zlower-impl-trait-in-trait-to-assoc-ty`, install the correct default trait method projection predicates (RPITIT -> opaque). This makes default trait body tests pass!

2. Fix two WF-checking bugs -- first, we want to make sure that we're always looking for an opaque type in `check_return_position_impl_trait_in_trait_bounds`. That's because the RPITIT projections are normalized to opaques during wfcheck. Second, fix RPITIT's param-envs by not adding the projection predicates that we install on trait methods to make default RPITITs work -- I left a comment why.

3. Also, just a small drive-by for `rustc_on_unimplemented`. Not sure if it affects any tests, but can't hurt.

r? ````@spastorino,```` based off of #109140
This commit is contained in:
Matthias Krüger 2023-03-17 08:42:40 +01:00 • committed by GitHub
commit 246d989a30
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50 changed files with 419 additions and 107 deletions
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18
compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
View file

@ -144,18 +144,22 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
trait_ref: ty::PolyTraitRef<'tcx>,
obligation: &PredicateObligation<'tcx>,
) -> OnUnimplementedNote {
if self.tcx.opt_rpitit_info(obligation.cause.body_id.to_def_id()).is_some() {
return OnUnimplementedNote::default();
}
let (def_id, substs) = self
.impl_similar_to(trait_ref, obligation)
.unwrap_or_else(|| (trait_ref.def_id(), trait_ref.skip_binder().substs));
let trait_ref = trait_ref.skip_binder();
let body_hir = self.tcx.hir().local_def_id_to_hir_id(obligation.cause.body_id);
let mut flags =
vec![(sym::ItemContext, self.describe_enclosure(body_hir).map(|s| s.to_owned()))];
let mut flags = vec![];
// FIXME(-Zlower-impl-trait-in-trait-to-assoc-ty): HIR is not present for RPITITs,
// but I guess we could synthesize one here. We don't see any errors that rely on
// that yet, though.
let enclosure =
if let Some(body_hir) = self.tcx.opt_local_def_id_to_hir_id(obligation.cause.body_id) {
self.describe_enclosure(body_hir).map(|s| s.to_owned())
} else {
None
};
flags.push((sym::ItemContext, enclosure));
match obligation.cause.code() {
ObligationCauseCode::BuiltinDerivedObligation(..)

4
compiler/rustc_trait_selection/src/traits/project.rs
View file

@ -1298,7 +1298,7 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
) {
let tcx = selcx.tcx();
if tcx.def_kind(obligation.predicate.def_id) == DefKind::ImplTraitPlaceholder {
let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.def_id);
let trait_fn_def_id = tcx.impl_trait_in_trait_parent_fn(obligation.predicate.def_id);
let trait_def_id = tcx.parent(trait_fn_def_id);
let trait_substs =
@ -2200,7 +2200,7 @@ fn confirm_impl_trait_in_trait_candidate<'tcx>(
let tcx = selcx.tcx();
let mut obligations = data.nested;
let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.def_id);
let trait_fn_def_id = tcx.impl_trait_in_trait_parent_fn(obligation.predicate.def_id);
let leaf_def = match specialization_graph::assoc_def(tcx, data.impl_def_id, trait_fn_def_id) {
Ok(assoc_ty) => assoc_ty,
Err(guar) => return Progress::error(tcx, guar),