Index: clangd/ClangdLSPServer.h
===================================================================
--- clangd/ClangdLSPServer.h
+++ clangd/ClangdLSPServer.h
@@ -155,6 +155,8 @@
   RealFileSystemProvider FSProvider;
   /// Options used for code completion
   clangd::CodeCompleteOptions CCOpts;
+  /// Options used for diagnostics.
+  ClangdDiagnosticOptions DiagOpts;
   /// The supported kinds of the client.
   SymbolKindBitset SupportedSymbolKinds;
 
Index: clangd/ClangdLSPServer.cpp
===================================================================
--- clangd/ClangdLSPServer.cpp
+++ clangd/ClangdLSPServer.cpp
@@ -82,6 +82,8 @@
 
   CCOpts.EnableSnippets =
       Params.capabilities.textDocument.completion.completionItem.snippetSupport;
+  DiagOpts.EmbedFixesInDiagnostics =
+      Params.capabilities.textDocument.publishDiagnostics.clangdFixSupport;
 
   if (Params.capabilities.workspace && Params.capabilities.workspace->symbol &&
       Params.capabilities.workspace->symbol->symbolKind) {
@@ -486,11 +488,25 @@
   DiagnosticToReplacementMap LocalFixIts; // Temporary storage
   for (auto &Diag : Diagnostics) {
     toLSPDiags(Diag, [&](clangd::Diagnostic Diag, llvm::ArrayRef<Fix> Fixes) {
-      DiagnosticsJSON.push_back(json::Object{
+      json::Object LSPDiag({
           {"range", Diag.range},
           {"severity", Diag.severity},
           {"message", Diag.message},
       });
+      // LSP extension: embed the fixes in the diagnostic.
+      if (DiagOpts.EmbedFixesInDiagnostics && !Fixes.empty()) {
+        json::Array ClangdFixes;
+        for (const auto &Fix : Fixes) {
+          WorkspaceEdit WE;
+          URIForFile URI{File};
+          WE.changes = {{URI.uri(), std::vector<TextEdit>(Fix.Edits.begin(),
+                                                          Fix.Edits.end())}};
+          ClangdFixes.push_back(
+              json::Object{{"edit", toJSON(WE)}, {"title", Fix.Message}});
+        }
+        LSPDiag["clangd_fixes"] = std::move(ClangdFixes);
+      }
+      DiagnosticsJSON.push_back(std::move(LSPDiag));
 
       auto &FixItsForDiagnostic = LocalFixIts[Diag];
       std::copy(Fixes.begin(), Fixes.end(),
Index: clangd/Diagnostics.h
===================================================================
--- clangd/Diagnostics.h
+++ clangd/Diagnostics.h
@@ -23,6 +23,12 @@
 namespace clang {
 namespace clangd {
 
+struct ClangdDiagnosticOptions {
+  /// If true, Clangd uses an LSP extension to embed the fixes with the
+  /// diagnostics that are sent to the client.
+  bool EmbedFixesInDiagnostics = false;
+};
+
 /// Contains basic information about a diagnostic.
 struct DiagBase {
   std::string Message;
Index: clangd/Protocol.h
===================================================================
--- clangd/Protocol.h
+++ clangd/Protocol.h
@@ -247,6 +247,18 @@
 };
 bool fromJSON(const llvm::json::Value &, CompletionClientCapabilities &);
 
+struct PublishDiagnosticsClientCapabilities {
+  // Whether the client accepts diagnostics with related information.
+  // NOTE: not used by clangd at the moment.
+  // bool relatedInformation;
+
+  /// Whether the client accepts diagnostics with fixes attached using the
+  /// "clangd_fixes" extension.
+  bool clangdFixSupport = false;
+};
+bool fromJSON(const llvm::json::Value &,
+              PublishDiagnosticsClientCapabilities &);
+
 /// A symbol kind.
 enum class SymbolKind {
   File = 1,
@@ -313,6 +325,9 @@
 struct TextDocumentClientCapabilities {
   /// Capabilities specific to the `textDocument/completion`
   CompletionClientCapabilities completion;
+
+  /// Capabilities specific to the 'textDocument/publishDiagnostics'
+  PublishDiagnosticsClientCapabilities publishDiagnostics;
 };
 bool fromJSON(const llvm::json::Value &, TextDocumentClientCapabilities &);
 
Index: clangd/Protocol.cpp
===================================================================
--- clangd/Protocol.cpp
+++ clangd/Protocol.cpp
@@ -178,6 +178,15 @@
   return true;
 }
 
+bool fromJSON(const llvm::json::Value &Params,
+              PublishDiagnosticsClientCapabilities &R) {
+  json::ObjectMapper O(Params);
+  if (!O)
+    return false;
+  O.map("clangdFixSupport", R.clangdFixSupport);
+  return true;
+}
+
 bool fromJSON(const json::Value &E, SymbolKind &Out) {
   if (auto T = E.getAsInteger()) {
     if (*T < static_cast<int>(SymbolKind::File) ||
@@ -240,6 +249,7 @@
   if (!O)
     return false;
   O.map("completion", R.completion);
+  O.map("publishDiagnostics", R.publishDiagnostics);
   return true;
 }