diff --git a/clang-tools-extra/clangd/ClangdServer.cpp b/clang-tools-extra/clangd/ClangdServer.cpp
--- a/clang-tools-extra/clangd/ClangdServer.cpp
+++ b/clang-tools-extra/clangd/ClangdServer.cpp
@@ -218,6 +218,7 @@
     BGOpts.ContextProvider = [this](PathRef P) {
       return createProcessingContext(P);
     };
+    BGOpts.CollectMainFileRefs = Opts.CollectMainFileRefs;
     BackgroundIdx = std::make_unique<BackgroundIndex>(
         TFS, CDB,
         BackgroundIndexStorage::createDiskBackedStorageFactory(