diff --git a/evm/src/generation/partial_trie.rs b/evm/src/generation/partial_trie.rs
index 509379aa..96751310 100644
--- a/evm/src/generation/partial_trie.rs
+++ b/evm/src/generation/partial_trie.rs
@@ -1,17 +1,25 @@
 use ethereum_types::U256;
 
-/// A partial trie, or a sub-trie thereof.
+/// A partial trie, or a sub-trie thereof. This mimics the structure of an Ethereum trie, except
+/// with an additional `Hash` node type, representing a node whose data is not needed to process
+/// our transaction.
 pub enum PartialTrie {
     /// An empty trie.
     Empty,
     /// The digest of trie whose data does not need to be stored.
     Hash(U256),
     /// A branch node, which consists of 16 children and an optional value.
-    Branch([Box<PartialTrie>; 16], Option<U256>),
+    Branch {
+        children: [Box<PartialTrie>; 16],
+        value: Option<U256>,
+    },
     /// An extension node, which consists of a list of nibbles and a single child.
-    Extension(Nibbles, Box<PartialTrie>),
+    Extension {
+        nibbles: Nibbles,
+        child: Box<PartialTrie>,
+    },
     /// A leaf node, which consists of a list of nibbles and a value.
-    Leaf(Nibbles, Vec<u8>),
+    Leaf { nibbles: Nibbles, value: Vec<u8> },
 }
 
 /// A sequence of nibbles.