Wow, it is possible to implement Index for Vec!

src/tree/file_builder.rs

@@ -81,7 +81,7 @@ impl FileBuilder {
     }
 
     fn add_len(&mut self, child: NodeIdx) {
-        let range = self.nodes[child.0 as usize].range;
+        let range = self.nodes[child].range;
         grow(&mut self.current_parent().range, range);
     }
 
@@ -90,13 +90,13 @@ impl FileBuilder {
     }
 
     fn current_parent(&mut self) -> &mut NodeData {
-        let NodeIdx(idx) = self.current_id();
-        &mut self.nodes[idx as usize]
+        let idx = self.current_id();
+        &mut self.nodes[idx]
     }
 
     fn current_sibling(&mut self) -> Option<&mut NodeData> {
-        let NodeIdx(idx) = self.in_progress.last().unwrap().1?;
-        Some(&mut self.nodes[idx as usize])
+        let idx = self.in_progress.last().unwrap().1?;
+        Some(&mut self.nodes[idx])
     }
 }
 

src/tree/mod.rs

@@ -70,7 +70,7 @@ impl<'f> Node<'f> {
 	}
 
 	fn data(&self) -> &'f NodeData {
-		&self.file.nodes[self.idx.0 as usize]
+		&self.file.nodes[self.idx]
 	}
 
 	fn as_node(&self, idx: Option<NodeIdx>) -> Option<Node<'f>> {
@@ -102,3 +102,17 @@ struct NodeData {
 	first_child: Option<NodeIdx>,
 	next_sibling: Option<NodeIdx>,
 }
+
+impl ::std::ops::Index<NodeIdx> for Vec<NodeData> {
+	type Output = NodeData;
+
+	fn index(&self, NodeIdx(idx): NodeIdx) -> &NodeData {
+		&self[idx as usize]
+	}
+}
+
+impl ::std::ops::IndexMut<NodeIdx> for Vec<NodeData> {
+	fn index_mut(&mut self, NodeIdx(idx): NodeIdx) -> &mut NodeData {
+		&mut self[idx as usize]
+	}
+}