diff --git a/clang-tools-extra/clangd/support/Function.h b/clang-tools-extra/clangd/support/Function.h
--- a/clang-tools-extra/clangd/support/Function.h
+++ b/clang-tools-extra/clangd/support/Function.h
@@ -51,7 +51,7 @@
     Subscription &operator=(Subscription &&Other) {
       // If *this is active, unsubscribe.
       if (Parent) {
-        std::lock_guard<std::recursive_mutex>(Parent->ListenersMu);
+        std::lock_guard<std::recursive_mutex> Lock(Parent->ListenersMu);
         llvm::erase_if(Parent->Listeners,
                        [&](const std::pair<Listener, unsigned> &P) {
                          return P.second == ListenerID;