rustdoc: hide reference methods in search index

src/librustdoc/formats/cache.rs

@@ -287,6 +287,10 @@ fn fold_item(&mut self, item: clean::Item) -> Option<clean::Item> {
                     } else {
                         let last = self.cache.parent_stack.last().expect("parent_stack is empty 2");
                         let did = match &*last {
+                            ParentStackItem::Impl {
+                                for_: clean::Type::BorrowedRef { type_, .. },
+                                ..
+                            } => type_.def_id(&self.cache),
                             ParentStackItem::Impl { for_, .. } => for_.def_id(&self.cache),
                             ParentStackItem::Type(item_id) => item_id.as_def_id(),
                         };

tests/rustdoc-js-std/reference-shrink.js

@@ -0,0 +1,8 @@
+// exact-check
+
+const QUERY = 'reference::shrink';
+
+const EXPECTED = {
+    // avoid including the method that's not going to be in the HTML
+    'others': [],
+};