diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp b/clang/lib/Analysis/UnsafeBufferUsage.cpp
--- a/clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -645,6 +645,7 @@
 public:
   DeclUseTracker() = default;
   DeclUseTracker(const DeclUseTracker &) = delete; // Let's avoid copies.
+  DeclUseTracker &operator=(const DeclUseTracker &) = delete;
   DeclUseTracker(DeclUseTracker &&) = default;
   DeclUseTracker &operator=(DeclUseTracker &&) = default;