diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index fdf094fae1e437b20d1a8972fd66358a5b91f217..f2319bfe64de8c02257f3fb0498ee77c3db1e01c 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -3125,6 +3125,9 @@ fn extern_prelude_get(
         })
     }
 
+    /// This is equivalent to `get_traits_in_module_containing_item`, but without filtering by the associated item.
+    ///
+    /// This is used by rustdoc for intra-doc links.
     pub fn traits_in_scope(&mut self, module_id: DefId) -> Vec<TraitCandidate> {
         let module = self.get_module(module_id);
         module.ensure_traits(self);