Auto merge of #55646 - GuillaumeGomez:rollup, r=GuillaumeGomez

Rollup of 5 pull requests

Successful merges:

 - #54162 (Hide default impls items)
 - #55555 (Make `-Z ls` list the actual filename of external dependencies)
 - #55567 (add test for deriving Debug on uninhabited enum)
 - #55568 (test that rustdoc doesn't overflow on a big enum)
 - #55598 (publish-toolstate: ping maintainers when a tool builds again)

Failed merges:

r? @ghost

src/librustdoc/clean/mod.rs

@@ -552,6 +552,14 @@ impl ItemEnum {
             _ => return None,
         })
     }
+
+    pub fn is_associated(&self) -> bool {
+        match *self {
+            ItemEnum::TypedefItem(_, _) |
+            ItemEnum::AssociatedTypeItem(_, _) => true,
+            _ => false,
+        }
+    }
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]