Index: clangd/Context.cpp
===================================================================
--- clangd/Context.cpp
+++ clangd/Context.cpp
@@ -13,7 +13,7 @@
 namespace clang {
 namespace clangd {
 
-Context Context::empty() { return Context(/*Data=*/nullptr); }
+Context Context::empty() { return Context(/*DataPtr=*/nullptr); }
 
 Context::Context(std::shared_ptr<const Data> DataPtr)
     : DataPtr(std::move(DataPtr)) {}
Index: clangd/tool/ClangdMain.cpp
===================================================================
--- clangd/tool/ClangdMain.cpp
+++ clangd/tool/ClangdMain.cpp
@@ -149,10 +149,11 @@
     return 1;
   }
 
-  // Ignore -j option if -run-synchonously is used.
-  // FIXME: a warning should be shown here.
-  if (RunSynchronously)
+  if (RunSynchronously) {
+    if (WorkerThreadsCount.getNumOccurrences())
+      llvm::errs() << "Ignoring -j because -run-synchronously is set.\n";
     WorkerThreadsCount = 0;
+  }
 
   // Validate command line arguments.
   llvm::Optional<llvm::raw_fd_ostream> InputMirrorStream;