From 5a2b335e498202e4470ccccd6cc32b0b4133738e Mon Sep 17 00:00:00 2001
From: Lukas Markeffsky <@>
Date: Sun, 21 Apr 2024 18:04:50 +0200
Subject: [PATCH] also remap RPITITs nested in other types back to their
 opaques

---
 compiler/rustc_hir_analysis/src/collect/item_bounds.rs | 4 ++--
 tests/ui/impl-trait/in-trait/nested-rpitit-bounds.rs   | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
index c2205815ba6..02291cc603e 100644
--- a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
+++ b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
@@ -4,7 +4,7 @@
 use rustc_hir as hir;
 use rustc_infer::traits::util;
 use rustc_middle::ty::GenericArgs;
-use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeFolder};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable};
 use rustc_span::def_id::{DefId, LocalDefId};
 use rustc_span::Span;
 
@@ -214,7 +214,7 @@ fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
         {
             self.tcx.type_of(projection_ty.def_id).instantiate(self.tcx, projection_ty.args)
         } else {
-            ty
+            ty.super_fold_with(self)
         }
     }
 }
diff --git a/tests/ui/impl-trait/in-trait/nested-rpitit-bounds.rs b/tests/ui/impl-trait/in-trait/nested-rpitit-bounds.rs
index 3a173efb32d..10c2a811243 100644
--- a/tests/ui/impl-trait/in-trait/nested-rpitit-bounds.rs
+++ b/tests/ui/impl-trait/in-trait/nested-rpitit-bounds.rs
@@ -6,6 +6,10 @@ trait Foo {
     fn foo() -> impl Deref<Target = impl Deref<Target = impl Sized>> {
         &&()
     }
+
+    fn bar() -> impl Deref<Target = Option<impl Sized>> {
+        &Some(())
+    }
 }
 
 fn main() {}