From 85848e1bbfbcccd5b3bc5344bed58c902091deef Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Sun, 16 Jun 2019 06:32:37 -0400
Subject: [PATCH] complete mysterious comments

---
 src/interned.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/interned.rs b/src/interned.rs
index 86351c75..145fc61a 100644
--- a/src/interned.rs
+++ b/src/interned.rs
@@ -252,7 +252,7 @@ where
     fn intern_check(&self, db: &DB, key: &Q::Key) -> Option<StampedValue<InternId>> {
         let revision_now = db.salsa_runtime().current_revision();
 
-        // First,
+        // First, try with read lock -- this only works if `accessed_at` is up to date.
         {
             let tables = self.tables.read();
             let &index = tables.map.get(key)?;
@@ -282,7 +282,7 @@ where
             }
         }
 
-        // Next,
+        // Acquire write lock if necessary.
         let mut tables = self.tables.write();
         let &index = tables.map.get(key)?;
         match &mut tables.values[index.as_usize()] {