Rollup merge of #106759 - compiler-errors:revert-105255, r=cjgillot

Revert "Make nested RPITIT inherit the parent opaque's generics."

This reverts commit e2d41f4, and adjusts the `tests/ui/async-await/in-trait/nested-rpit.rs` test.

r? `@cjgillot`

fixes #106332, manually verified because it had no minimization :/

reopens #105197
cc #106729

compiler/rustc_hir_analysis/src/collect/generics_of.rs

@@ -4,6 +4,7 @@ use hir::{
     GenericParamKind, HirId, Node,
 };
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::lint;
@@ -142,7 +143,20 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
             Some(tcx.typeck_root_def_id(def_id))
         }
         Node::Item(item) => match item.kind {
-            ItemKind::OpaqueTy(hir::OpaqueTy { .. }) => {
+            ItemKind::OpaqueTy(hir::OpaqueTy {
+                origin:
+                    hir::OpaqueTyOrigin::FnReturn(fn_def_id) | hir::OpaqueTyOrigin::AsyncFn(fn_def_id),
+                in_trait,
+                ..
+            }) => {
+                if in_trait {
+                    assert!(matches!(tcx.def_kind(fn_def_id), DefKind::AssocFn))
+                } else {
+                    assert!(matches!(tcx.def_kind(fn_def_id), DefKind::AssocFn | DefKind::Fn))
+                }
+                Some(fn_def_id.to_def_id())
+            }
+            ItemKind::OpaqueTy(hir::OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => {
                 let parent_id = tcx.hir().get_parent_item(hir_id);
                 assert_ne!(parent_id, hir::CRATE_OWNER_ID);
                 debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id);

tests/ui/async-await/in-trait/nested-rpit.rs

@@ -1,5 +1,7 @@
-// check-pass
 // edition: 2021
+// known-bug: #105197
+// failure-status:101
+// dont-check-compiler-stderr
 
 #![feature(async_fn_in_trait)]
 #![feature(return_position_impl_trait_in_trait)]