Rollup merge of #113741 - compiler-errors:rpitit-projects-to-missing-opaque, r=spastorino

Don't install default projection bound for return-position `impl Trait` in trait methods with no body

This ensures that we never try to project to an opaque type in a trait method that has no body to infer its hidden type, which means we never later call `type_of` on that opaque. This is because opaque types try to reveal their hidden type when proving auto traits.

I thought about this a lot, and I think this is a fix that's less likely to introduce other strange downstream ICEs than #113461.

Fixes #113434

r? `@spastorino`

1 files changed, 1 insertions, 7 deletions

diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 0025dc9033c..d72053ca985 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1144,13 +1144,7 @@ fn should_encode_type(tcx: TyCtxt<'_>, def_id: LocalDefId, def_kind: DefKind) ->
             let assoc_item = tcx.associated_item(def_id);
             match assoc_item.container {
                 ty::AssocItemContainer::ImplContainer => true,
-                // Always encode RPITITs, since we need to be able to project
-                // from an RPITIT associated item to an opaque when installing
-                // the default projection predicates in default trait methods
-                // with RPITITs.
-                ty::AssocItemContainer::TraitContainer => {
-                    assoc_item.defaultness(tcx).has_value() || assoc_item.is_impl_trait_in_trait()
-                }
+                ty::AssocItemContainer::TraitContainer => assoc_item.defaultness(tcx).has_value(),
             }
         }
         DefKind::TyParam => {