diff --git a/crates/ra_proc_macro/src/process.rs b/crates/ra_proc_macro/src/process.rs
index a9095af111d..6a3fe2e2025 100644
--- a/crates/ra_proc_macro/src/process.rs
+++ b/crates/ra_proc_macro/src/process.rs
@@ -1,3 +1,5 @@
+//! Handle process life-time and message passing for proc-macro client
+
 use crossbeam_channel::{bounded, Receiver, Sender};
 use ra_tt::Subtree;