1 files changed, 1 insertions, 0 deletions
diff --git a/prelude.rb b/prelude.rb
index 20a9e2df10..8a172a22e9 100644
--- a/prelude.rb
+++ b/prelude.rb
@@ -8,6 +8,7 @@ class Thread
   # value of the block. A thread executing inside the exclusive section will
   # only block other threads which also use the Thread.exclusive mechanism.
   def self.exclusive
+    warn "Thread.exclusive is deprecated, use Mutex", caller
     MUTEX_FOR_THREAD_EXCLUSIVE.synchronize{
       yield
     }