collect impl items from the HIR if available

Author: QuietMisdreavus

src/librustdoc/clean/inline.rs

@@ -335,13 +335,24 @@ pub fn build_impl(cx: &DocContext, did: DefId, ret: &mut Vec<clean::Item>) {
     }
 
     let predicates = tcx.predicates_of(did);
-    let trait_items = tcx.associated_items(did).filter_map(|item| {
-        if associated_trait.is_some() || item.vis == ty::Visibility::Public {
-            Some(item.clean(cx))
-        } else {
-            None
+    let trait_items = if let Some(nodeid) = tcx.hir.as_local_node_id(did) {
+        match tcx.hir.expect_item(nodeid).node {
+            hir::ItemKind::Impl(.., ref item_ids) => {
+                item_ids.iter()
+                        .map(|ii| tcx.hir.impl_item(ii.id).clean(cx))
+                        .collect::<Vec<_>>()
+            }
+            _ => panic!("did given to build_impl was not an impl"),
         }
-    }).collect::<Vec<_>>();
+    } else {
+        tcx.associated_items(did).filter_map(|item| {
+            if associated_trait.is_some() || item.vis == ty::Visibility::Public {
+                Some(item.clean(cx))
+            } else {
+                None
+            }
+        }).collect::<Vec<_>>()
+    };
     let polarity = tcx.impl_polarity(did);
     let trait_ = associated_trait.clean(cx).map(|bound| {
         match bound {