diff --git a/tools/llvm-diff/DiffConsumer.h b/tools/llvm-diff/DiffConsumer.h
index e5510cc..b95d427 100644
--- a/tools/llvm-diff/DiffConsumer.h
+++ b/tools/llvm-diff/DiffConsumer.h
@@ -28,7 +28,8 @@
   class Function;
 
   /// The interface for consumers of difference data.
-  struct Consumer {
+  class Consumer {
+  public:
     /// Record that a local context has been entered.  Left and
     /// Right are IR "containers" of some sort which are being
     /// considered for structural equivalence: global variables,