Make small modifications

src/librustc/hir/map/collector.rs

@@ -115,7 +115,7 @@ pub(super) fn root(krate: &'hir Crate,
             hir_body_nodes,
         };
         collector.insert_entry(CRATE_NODE_ID, Entry {
-            parent: ast::DUMMY_NODE_ID,
+            parent: CRATE_NODE_ID,
             dep_node: root_mod_sig_dep_index,
             node: Node::Crate,
         });

src/librustc/hir/map/mod.rs

@@ -59,13 +59,6 @@ fn parent_node(self) -> Option<NodeId> {
         }
     }
 
-    fn to_node(self) -> Option<Node<'hir>> {
-        match self.node {
-            Node::Crate => None,
-            _ => Some(self.node),
-        }
-    }
-
     fn fn_decl(&self) -> Option<&FnDecl> {
         match self.node {
             Node::Item(ref item) => {
@@ -568,7 +561,7 @@ pub fn get_generics_span(&self, id: DefId) -> Option<Span> {
     /// Retrieve the Node corresponding to `id`, returning None if
     /// cannot be found.
     pub fn find(&self, id: NodeId) -> Option<Node<'hir>> {
-        let result = self.find_entry(id).and_then(|x| x.to_node());
+        let result = self.find_entry(id).map(|x| x.node);
         if result.is_some() {
             self.read(id);
         }
@@ -638,16 +631,11 @@ fn walk_parent_nodes<F, F2>(&self,
                 return Err(id);
             }
 
-            if let Some(node) = self.find_entry(parent_node) {
-                match node.to_node() {
-                    Some(ref node) => {
-                        if found(node) {
-                            return Ok(parent_node);
-                        } else if bail_early(node) {
-                            return Err(parent_node);
-                        }
-                    }
-                    None => return Err(parent_node),
+            if let Some(entry) = self.find_entry(parent_node) {
+                if found(&entry.node) {
+                    return Ok(parent_node);
+                } else if bail_early(&entry.node) {
+                    return Err(parent_node);
                 }
                 id = parent_node;
             } else {

src/librustc/hir/mod.rs

@@ -2397,7 +2397,5 @@ pub enum Node<'hir> {
     GenericParam(&'hir GenericParam),
     Visibility(&'hir Visibility),
 
-    /// Roots for node trees. Its DepNodeIndex when in `Entry`
-    /// is the dependency node of the crate's root module.
     Crate,
 }