diff --git a/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h b/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h
--- a/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h
+++ b/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h
@@ -141,8 +141,7 @@
 /// \c DependencyConsumer of the parent \c ModuleDepCollector.
 class ModuleDepCollectorPP final : public PPCallbacks {
 public:
-  ModuleDepCollectorPP(CompilerInstance &I, ModuleDepCollector &MDC)
-      : Instance(I), MDC(MDC) {}
+  ModuleDepCollectorPP(ModuleDepCollector &MDC) : MDC(MDC) {}
 
   void FileChanged(SourceLocation Loc, FileChangeReason Reason,
                    SrcMgr::CharacteristicKind FileType,
@@ -159,8 +158,6 @@
   void EndOfMainFile() override;
 
 private:
-  /// The compiler instance for the current translation unit.
-  CompilerInstance &Instance;
   /// The parent dependency collector.
   ModuleDepCollector &MDC;
   /// Working set of direct modular dependencies.
diff --git a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
--- a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
+++ b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
@@ -138,11 +138,11 @@
   // This has to be delayed as the context hash can change at the start of
   // `CompilerInstance::ExecuteAction`.
   if (MDC.ContextHash.empty()) {
-    MDC.ContextHash = Instance.getInvocation().getModuleHash();
+    MDC.ContextHash = MDC.Instance.getInvocation().getModuleHash();
     MDC.Consumer.handleContextHash(MDC.ContextHash);
   }
 
-  SourceManager &SM = Instance.getSourceManager();
+  SourceManager &SM = MDC.Instance.getSourceManager();
 
   // Dependency generation really does want to go all the way to the
   // file entry for a source location to find out what is depended on.
@@ -185,12 +185,13 @@
 }
 
 void ModuleDepCollectorPP::EndOfMainFile() {
-  FileID MainFileID = Instance.getSourceManager().getMainFileID();
+  FileID MainFileID = MDC.Instance.getSourceManager().getMainFileID();
   MDC.MainFile = std::string(
-      Instance.getSourceManager().getFileEntryForID(MainFileID)->getName());
+      MDC.Instance.getSourceManager().getFileEntryForID(MainFileID)->getName());
 
-  if (!Instance.getPreprocessorOpts().ImplicitPCHInclude.empty())
-    MDC.FileDeps.push_back(Instance.getPreprocessorOpts().ImplicitPCHInclude);
+  if (!MDC.Instance.getPreprocessorOpts().ImplicitPCHInclude.empty())
+    MDC.FileDeps.push_back(
+        MDC.Instance.getPreprocessorOpts().ImplicitPCHInclude);
 
   for (const Module *M : DirectModularDeps) {
     // A top-level module might not be actually imported as a module when
@@ -229,7 +230,7 @@
   MD.ImplicitModulePCMPath = std::string(M->getASTFile()->getName());
   MD.IsSystem = M->IsSystem;
 
-  const FileEntry *ModuleMap = Instance.getPreprocessor()
+  const FileEntry *ModuleMap = MDC.Instance.getPreprocessor()
                                    .getHeaderSearchInfo()
                                    .getModuleMap()
                                    .getModuleMapFileForUniquing(M);
@@ -319,7 +320,7 @@
       OriginalInvocation(std::move(OriginalCI)), OptimizeArgs(OptimizeArgs) {}
 
 void ModuleDepCollector::attachToPreprocessor(Preprocessor &PP) {
-  PP.addPPCallbacks(std::make_unique<ModuleDepCollectorPP>(Instance, *this));
+  PP.addPPCallbacks(std::make_unique<ModuleDepCollectorPP>(*this));
 }
 
 void ModuleDepCollector::attachToASTReader(ASTReader &R) {}