diff --git a/clang-tools-extra/clangd/ClangdLSPServer.cpp b/clang-tools-extra/clangd/ClangdLSPServer.cpp
--- a/clang-tools-extra/clangd/ClangdLSPServer.cpp
+++ b/clang-tools-extra/clangd/ClangdLSPServer.cpp
@@ -986,9 +986,9 @@
 
   // Now enumerate the semantic code actions.
   auto ConsumeActions =
-      [Reply = std::move(Reply), File, Selection = Params.range,
-       FixIts = std::move(FixIts), this](
-          llvm::Expected<std::vector<ClangdServer::TweakRef>> Tweaks) mutable {
+      [Diags = Params.context.diagnostics, Reply = std::move(Reply), File,
+       Selection = Params.range, FixIts = std::move(FixIts), this](
+        llvm::Expected<std::vector<ClangdServer::TweakRef>> Tweaks) mutable {
         if (!Tweaks)
           return Reply(Tweaks.takeError());
 
@@ -999,17 +999,21 @@
 
         // If there's exactly one quick-fix, call it "preferred".
         // We never consider refactorings etc as preferred.
-        CodeAction *OnlyFix = nullptr;
+        Optional<CodeAction *> OnlyFix; // nullptr means multiple fixes
         for (auto &Action : Actions) {
           if (Action.kind && *Action.kind == CodeAction::QUICKFIX_KIND) {
             if (OnlyFix) {
-              OnlyFix->isPreferred = false;
+              *OnlyFix = nullptr;
               break;
             }
-            Action.isPreferred = true;
             OnlyFix = &Action;
           }
         }
+        if (OnlyFix && *OnlyFix) {
+          (*OnlyFix)->isPreferred = true;
+          if (Diags.size() == 1 && Diags.front().range == Selection)
+            (*OnlyFix)->diagnostics = {Diags.front()};
+        }
 
         if (SupportsCodeAction)
           return Reply(llvm::json::Array(Actions));