diff --git a/grep-printer/src/macros.rs b/grep-printer/src/macros.rs
index 7b48e8c2..0b1e764b 100644
--- a/grep-printer/src/macros.rs
+++ b/grep-printer/src/macros.rs
@@ -1,3 +1,4 @@
+/// Like assert_eq, but nicer output for long strings.
 #[cfg(test)]
 #[macro_export]
 macro_rules! assert_eq_printed {