diff --git a/src/linq/index.md b/src/linq/index.md
index 7196515..b3d04fe 100644
--- a/src/linq/index.md
+++ b/src/linq/index.md
@@ -159,6 +159,7 @@ array instead of a vector. Consider just the summing loop from the above
 example over an array of a structure that wraps an integer:
 
 ```rust
+#[derive(Debug)]
 struct Int(i32);
 
 impl Drop for Int {
@@ -172,6 +173,7 @@ fn main() {
     let mut sum = 0;
 
     for value in values {
+        println!("value = {:?}", value);
         sum += value.0;
     }