From 7bae5bd828e98af9d245b77118c075a7f1a036b9 Mon Sep 17 00:00:00 2001
From: flip1995 <hello@philkrones.com>
Date: Sat, 23 Nov 2019 01:26:19 +0100
Subject: [PATCH] Add comment for mir_opt_level=0

---
 src/driver.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/driver.rs b/src/driver.rs
index bd19127b3ce8..2a4448cc0ec4 100644
--- a/src/driver.rs
+++ b/src/driver.rs
@@ -76,6 +76,10 @@ impl rustc_driver::Callbacks for ClippyCallbacks {
             clippy_lints::register_renamed(&mut lint_store);
         }));
 
+        // FIXME: #4825; This is required, because Clippy lints that are based on MIR have to be
+        // run on the unoptimized MIR. On the other hand this results in some false negatives. If
+        // MIR passes can be enabled / disabled separately, we should figure out, what passes to
+        // use for Clippy.
         config.opts.debugging_opts.mir_opt_level = 0;
     }
 }