diff --git a/clang-tools-extra/clang-tidy/ClangTidy.cpp b/clang-tools-extra/clang-tidy/ClangTidy.cpp
index 7de313ad4da6..697f98c362d1 100644
--- a/clang-tools-extra/clang-tidy/ClangTidy.cpp
+++ b/clang-tools-extra/clang-tidy/ClangTidy.cpp
@@ -432,6 +432,7 @@ ClangTidyASTConsumerFactory::createASTConsumer(
 
   for (auto &Check : Checks) {
     Check->registerMatchers(&*Finder);
+    Check->registerPPCallbacks(Compiler);
     Check->registerPPCallbacks(*SM, PP, ModuleExpanderPP);
   }
 
diff --git a/clang-tools-extra/clang-tidy/ClangTidyCheck.h b/clang-tools-extra/clang-tidy/ClangTidyCheck.h
index 9b41e5836de7..d8938b8fe05e 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyCheck.h
+++ b/clang-tools-extra/clang-tidy/ClangTidyCheck.h
@@ -20,6 +20,7 @@
 
 namespace clang {
 
+class CompilerInstance;
 class SourceManager;
 
 namespace tidy {
@@ -69,6 +70,9 @@ public:
     return true;
   }
 
+  /// This has been deprecated in clang 9 - needed by mozilla-must-override
+  virtual void registerPPCallbacks(CompilerInstance &Compiler) {}
+
   /// Override this to register ``PPCallbacks`` in the preprocessor.
   ///
   /// This should be used for clang-tidy checks that analyze preprocessor-