diff --git a/runtime/src/accounts_index.rs b/runtime/src/accounts_index.rs
index 34a9b76e09..a39bd95317 100644
--- a/runtime/src/accounts_index.rs
+++ b/runtime/src/accounts_index.rs
@@ -253,6 +253,7 @@ impl<T: IndexValue> AccountMapEntryInner<T> {
 }
 
 pub enum AccountIndexGetResult<T: IndexValue> {
+    /// (index entry, index in slot list)
     Found(ReadAccountMapEntry<T>, usize),
     NotFound,
 }