Rollup merge of #109405 - compiler-errors:rpitit-as-opaques, r=spastorino

RPITITs are `DefKind::Opaque` with new lowering strategy

r? `@spastorino`

Kinda cherry-picked #109400

compiler/rustc_middle/src/hir/map/mod.rs

@@ -188,7 +188,7 @@ impl<'hir> Map<'hir> {
                 ItemKind::Macro(_, macro_kind) => DefKind::Macro(macro_kind),
                 ItemKind::Mod(..) => DefKind::Mod,
                 ItemKind::OpaqueTy(ref opaque) => {
-                    if opaque.in_trait {
+                    if opaque.in_trait && !self.tcx.lower_impl_trait_in_trait_to_assoc_ty() {
                         DefKind::ImplTraitPlaceholder
                     } else {
                         DefKind::OpaqueTy