Index: clangd/ClangdServer.h
===================================================================
--- clangd/ClangdServer.h
+++ clangd/ClangdServer.h
@@ -187,13 +187,6 @@
                     llvm::Optional<StringRef> OverridenContents = llvm::None,
                     IntrusiveRefCntPtr<vfs::FileSystem> *UsedFS = nullptr);
 
-  /// DEPRECATED: Please use the callback-based version of codeComplete.
-  std::future<Tagged<CompletionList>>
-  codeComplete(PathRef File, Position Pos,
-               const clangd::CodeCompleteOptions &Opts,
-               llvm::Optional<StringRef> OverridenContents = llvm::None,
-               IntrusiveRefCntPtr<vfs::FileSystem> *UsedFS = nullptr);
-
   /// Provide signature help for \p File at \p Pos. If \p OverridenContents is
   /// not None, they will used only for signature help, i.e. no diagnostics
   /// update will be scheduled and a draft for \p File will not be updated. If
Index: clangd/ClangdServer.cpp
===================================================================
--- clangd/ClangdServer.cpp
+++ clangd/ClangdServer.cpp
@@ -166,24 +166,6 @@
                                  std::move(TaggedFS));
 }
 
-std::future<Tagged<CompletionList>>
-ClangdServer::codeComplete(PathRef File, Position Pos,
-                           const clangd::CodeCompleteOptions &Opts,
-                           llvm::Optional<StringRef> OverridenContents,
-                           IntrusiveRefCntPtr<vfs::FileSystem> *UsedFS) {
-  std::promise<Tagged<CompletionList>> ResultPromise;
-  auto Callback = [](std::promise<Tagged<CompletionList>> ResultPromise,
-                     Tagged<CompletionList> Result) -> void {
-    ResultPromise.set_value(std::move(Result));
-  };
-
-  auto ResultFuture = ResultPromise.get_future();
-  codeComplete(File, Pos, Opts,
-               BindWithForward(Callback, std::move(ResultPromise)),
-               OverridenContents, UsedFS);
-  return ResultFuture;
-}
-
 void ClangdServer::codeComplete(
     PathRef File, Position Pos, const clangd::CodeCompleteOptions &Opts,
     UniqueFunction<void(Tagged<CompletionList>)> Callback,
Index: unittests/clangd/ClangdTests.cpp
===================================================================
--- unittests/clangd/ClangdTests.cpp
+++ unittests/clangd/ClangdTests.cpp
@@ -9,6 +9,7 @@
 
 #include "ClangdLSPServer.h"
 #include "ClangdServer.h"
+#include "SyncAPI.h"
 #include "TestFS.h"
 #include "clang/Config/config.h"
 #include "llvm/ADT/SmallVector.h"
@@ -301,14 +302,14 @@
   // thread.
   FS.Tag = "123";
   Server.addDocument(FooCpp, SourceContents);
-  EXPECT_EQ(Server.codeComplete(FooCpp, Position{0, 0}, CCOpts).get().Tag,
+  EXPECT_EQ(runCodeComplete(Server, FooCpp, Position{0, 0}, CCOpts).Tag,
             FS.Tag);
   EXPECT_EQ(DiagConsumer.lastVFSTag(), FS.Tag);
 
   FS.Tag = "321";
   Server.addDocument(FooCpp, SourceContents);
   EXPECT_EQ(DiagConsumer.lastVFSTag(), FS.Tag);
-  EXPECT_EQ(Server.codeComplete(FooCpp, Position{0, 0}, CCOpts).get().Tag,
+  EXPECT_EQ(runCodeComplete(Server, FooCpp, Position{0, 0}, CCOpts).Tag,
             FS.Tag);
 }
 
@@ -637,10 +638,8 @@
       // requests as opposed to AddDocument/RemoveDocument, which are implicitly
       // cancelled by any subsequent AddDocument/RemoveDocument request to the
       // same file.
-      Server
-          .codeComplete(FilePaths[FileIndex], Pos,
-                        clangd::CodeCompleteOptions())
-          .wait();
+      runCodeComplete(Server, FilePaths[FileIndex], Pos,
+                      clangd::CodeCompleteOptions());
     };
 
     auto FindDefinitionsRequest = [&]() {
Index: unittests/clangd/CodeCompleteTests.cpp
===================================================================
--- unittests/clangd/CodeCompleteTests.cpp
+++ unittests/clangd/CodeCompleteTests.cpp
@@ -14,6 +14,7 @@
 #include "Matchers.h"
 #include "Protocol.h"
 #include "SourceCode.h"
+#include "SyncAPI.h"
 #include "TestFS.h"
 #include "index/MemIndex.h"
 #include "gmock/gmock.h"
@@ -121,8 +122,7 @@
   auto File = getVirtualTestFilePath("foo.cpp");
   Annotations Test(Text);
   Server.addDocument(File, Test.code()).wait();
-  auto CompletionList =
-      Server.codeComplete(File, Test.point(), Opts).get().Value;
+  auto CompletionList = runCodeComplete(Server, File, Test.point(), Opts).Value;
   // Sanity-check that filterText is valid.
   EXPECT_THAT(CompletionList.items, Each(NameContainsFilter()));
   return CompletionList;
@@ -348,10 +348,8 @@
 
   Annotations Example("int cbc; int b = ^;");
   auto Results =
-      Server
-          .codeComplete(File, Example.point(), clangd::CodeCompleteOptions(),
-                        StringRef(Example.code()))
-          .get()
+      runCodeComplete(Server, File, Example.point(),
+                      clangd::CodeCompleteOptions(), StringRef(Example.code()))
           .Value;
   EXPECT_THAT(Results.items, Contains(Named("cbc")));
 }
@@ -556,17 +554,17 @@
   Server.addDocument(File, Test.code()).wait();
   clangd::CodeCompleteOptions Opts = {};
 
-  auto WithoutIndex = Server.codeComplete(File, Test.point(), Opts).get().Value;
+  auto WithoutIndex = runCodeComplete(Server, File, Test.point(), Opts).Value;
   EXPECT_THAT(WithoutIndex.items,
               UnorderedElementsAre(Named("local"), Named("preamble")));
 
   auto I = memIndex({var("ns::index")});
   Opts.Index = I.get();
-  auto WithIndex = Server.codeComplete(File, Test.point(), Opts).get().Value;
+  auto WithIndex = runCodeComplete(Server, File, Test.point(), Opts).Value;
   EXPECT_THAT(WithIndex.items,
               UnorderedElementsAre(Named("local"), Named("index")));
   auto ClassFromPreamble =
-      Server.codeComplete(File, Test.point("2"), Opts).get().Value;
+      runCodeComplete(Server, File, Test.point("2"), Opts).Value;
   EXPECT_THAT(ClassFromPreamble.items, Contains(Named("member")));
 }
 
@@ -595,7 +593,7 @@
   )cpp");
   Server.addDocument(File, Test.code()).wait();
 
-  auto Results = Server.codeComplete(File, Test.point(), {}).get().Value;
+  auto Results = runCodeComplete(Server, File, Test.point(), {}).Value;
   // "XYZ" and "foo" are not included in the file being completed but are still
   // visible through the index.
   EXPECT_THAT(Results.items, Has("XYZ", CompletionItemKind::Class));
Index: unittests/clangd/SyncAPI.h
===================================================================
--- /dev/null
+++ unittests/clangd/SyncAPI.h
@@ -0,0 +1,34 @@
+//===--- SyncAPI.h - Sync version of ClangdServer's API ----------*- C++-*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===---------------------------------------------------------------------===//
+#ifndef LLVM_CLANG_TOOLS_EXTRA_UNITTESTS_CLANGD_SYNCAPI_H
+#define LLVM_CLANG_TOOLS_EXTRA_UNITTESTS_CLANGD_SYNCAPI_H
+
+#include "ClangdServer.h"
+#include <future>
+
+namespace clang {
+namespace clangd {
+inline Tagged<CompletionList>
+runCodeComplete(ClangdServer &Server, PathRef File, Position Pos,
+                clangd::CodeCompleteOptions Opts,
+                llvm::Optional<StringRef> OverridenContents = llvm::None) {
+  std::promise<Tagged<CompletionList>> Promise;
+  auto Future = Promise.get_future();
+  auto SetResult = [](decltype(Promise) Promise, Tagged<CompletionList> Value) {
+    Promise.set_value(std::move(Value));
+  };
+  Server.codeComplete(File, Pos, Opts,
+                      BindWithForward(SetResult, std::move(Promise)),
+                      OverridenContents);
+  return Future.get();
+}
+} // namespace clangd
+} // namespace clang
+
+#endif