rustdoc: fix sidebar_deref_methods

Author: lolbinarycat

src/librustdoc/html/render/sidebar.rs

@@ -533,7 +533,10 @@ fn sidebar_deref_methods<'a>(
             debug!("found inner_impl: {impls:?}");
             let mut ret = impls
                 .iter()
-                .filter(|i| i.inner_impl().trait_.is_none())
+                .filter(|i| {
+                    i.inner_impl().trait_.is_none()
+                        && real_target.is_doc_subtype_of(&i.inner_impl().for_, &c)
+                })
                 .flat_map(|i| get_methods(i.inner_impl(), true, used_links, deref_mut, cx.tcx()))
                 .collect::<Vec<_>>();
             if !ret.is_empty() {