diff --git a/clang-tools-extra/clangd/index/dex/dexp/Dexp.cpp b/clang-tools-extra/clangd/index/dex/dexp/Dexp.cpp
--- a/clang-tools-extra/clangd/index/dex/dexp/Dexp.cpp
+++ b/clang-tools-extra/clangd/index/dex/dexp/Dexp.cpp
@@ -283,7 +283,7 @@
   };
 
 public:
-  void run() {
+  void run() override {
     using namespace clang::clangd;
     // Read input file (as specified in global option)
     auto Buffer = llvm::MemoryBuffer::getFile(IndexLocation);