Introduce trait_item_of

1 files changed, 9 insertions, 0 deletions

diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index da17ec1f9f3..5a4ebfe28a4 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -1934,6 +1934,15 @@ impl<'tcx> TyCtxt<'tcx> {
         Some((parent, def_kind))
     }
 
+    /// Returns the trait item that is implemented by the given item `DefId`.
+    pub fn trait_item_of(self, def_id: impl IntoQueryParam<DefId>) -> Option<DefId> {
+        let assoc = self.opt_associated_item(def_id.into_query_param())?;
+        if assoc.container != AssocItemContainer::Impl {
+            return None;
+        }
+        assoc.trait_item_def_id
+    }
+
     /// If the given `DefId` is an associated item of a trait,
     /// returns the `DefId` of the trait; otherwise, returns `None`.
     pub fn trait_of_assoc(self, def_id: DefId) -> Option<DefId> {