From cc5c1a0abb1a4e25c8a40126991acce4c34508c4 Mon Sep 17 00:00:00 2001
From: bjorn3 <bjorn3@users.noreply.github.com>
Date: Mon, 4 Jun 2018 12:14:50 +0200
Subject: [PATCH] Add comment

---
 src/librustc_driver/driver.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs
index 7b177d5e79c1..8dcbda917b24 100644
--- a/src/librustc_driver/driver.rs
+++ b/src/librustc_driver/driver.rs
@@ -414,6 +414,18 @@ impl<'a> CompileController<'a> {
     }
 }
 
+/// This implementation makes it easier to create a custom driver when you only want to hook
+/// into callbacks from `CompileController`.
+///
+/// # Example
+///
+/// ```no_run
+/// # extern crate rustc_driver;
+/// # use rustc_driver::driver::CompileController;
+/// let mut controller = CompileController::basic();
+/// controller.after_analysis.callback = Box::new(move |_state| {});
+/// rustc_driver::run_compiler(&[], Box::new(controller), None, None);
+/// ```
 impl<'a> ::CompilerCalls<'a> for CompileController<'a> {
     fn early_callback(
         &mut self,