From 47860ddf589349cd905b2d9101227c2d8d9ca63c Mon Sep 17 00:00:00 2001
From: Santiago Pastorino <spastorino@gmail.com>
Date: Mon, 6 Mar 2023 11:33:51 -0300
Subject: [PATCH] Add is_impl_trait_in_trait

---
 compiler/rustc_middle/src/ty/context.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index f87bc45e4f2..4aa60f5eebf 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -2443,6 +2443,14 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn lower_impl_trait_in_trait_to_assoc_ty(self) -> bool {
         self.sess.opts.unstable_opts.lower_impl_trait_in_trait_to_assoc_ty
     }
+
+    pub fn is_impl_trait_in_trait(self, def_id: DefId) -> bool {
+        if self.lower_impl_trait_in_trait_to_assoc_ty() {
+            self.def_kind(def_id) == DefKind::AssocTy && self.opt_rpitit_info(def_id).is_some()
+        } else {
+            self.def_kind(def_id) == DefKind::ImplTraitPlaceholder
+        }
+    }
 }
 
 impl<'tcx> TyCtxtAt<'tcx> {