Index: clangd/ClangdUnit.cpp
===================================================================
--- clangd/ClangdUnit.cpp
+++ clangd/ClangdUnit.cpp
@@ -328,6 +328,8 @@
   // to read back. We rely on dynamic index for the comments instead.
   CI.getPreprocessorOpts().WriteCommentListToPCH = false;
 
+  PreambleDiagsEngine->setSuppressAfterFatalError(false);
+
   CppFilePreambleCallbacks SerializedDeclsCollector(FileName, PreambleCallback);
   if (Inputs.FS->setCurrentWorkingDirectory(Inputs.CompileCommand.Directory)) {
     log("Couldn't set working directory when building the preamble.");
Index: clangd/Compiler.cpp
===================================================================
--- clangd/Compiler.cpp
+++ clangd/Compiler.cpp
@@ -63,6 +63,7 @@
   auto Clang = llvm::make_unique<CompilerInstance>(PCHs);
   Clang->setInvocation(std::move(CI));
   Clang->createDiagnostics(&DiagsClient, false);
+  Clang->getDiagnostics().setSuppressAfterFatalError(false);
 
   if (auto VFSWithRemapping = createVFSFromCompilerInvocation(
           Clang->getInvocation(), Clang->getDiagnostics(), VFS))
Index: test/clangd/missing-includes.test
===================================================================
--- test/clangd/missing-includes.test
+++ test/clangd/missing-includes.test
@@ -0,0 +1,13 @@
+# RUN: clangd -lit-test < %s | FileCheck %s
+{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootPath":"clangd","capabilities":{},"trace":"off"}}
+---
+{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"test:///foo.c","languageId":"c","version":1,"text":"#include <a>\n#include <b>\nint x;\n#include <c>\n#include <d>\n"}}}
+# CHECK:  "method": "textDocument/publishDiagnostics",
+# CHECK:  "message": "'a' file not found",
+# CHECK:  "message": "'b' file not found",
+# CHECK:  "message": "'c' file not found",
+# CHECK:  "message": "'d' file not found",
+---
+{"jsonrpc":"2.0","id":5,"method":"shutdown"}
+---
+{"jsonrpc":"2.0","method":"exit"}