Index: clang/include/clang/Basic/Module.h
===================================================================
--- clang/include/clang/Basic/Module.h
+++ clang/include/clang/Basic/Module.h
@@ -662,7 +662,7 @@
   StringRef Path;
   StringRef ASTFile;
   ASTFileSignature Signature;
-  const Module *ClangModule = nullptr;
+  Module *ClangModule = nullptr;
 
 public:
   ASTSourceDescriptor() = default;
@@ -670,13 +670,13 @@
                       ASTFileSignature Signature)
       : PCHModuleName(std::move(Name)), Path(std::move(Path)),
         ASTFile(std::move(ASTFile)), Signature(Signature) {}
-  ASTSourceDescriptor(const Module &M);
+  ASTSourceDescriptor(Module &M);
 
   std::string getModuleName() const;
   StringRef getPath() const { return Path; }
   StringRef getASTFile() const { return ASTFile; }
   ASTFileSignature getSignature() const { return Signature; }
-  const Module *getModuleOrNull() const { return ClangModule; }
+  Module *getModuleOrNull() const { return ClangModule; }
 };
 
 
Index: clang/lib/Basic/Module.cpp
===================================================================
--- clang/lib/Basic/Module.cpp
+++ clang/lib/Basic/Module.cpp
@@ -659,7 +659,7 @@
   VisitModule({M, nullptr});
 }
 
-ASTSourceDescriptor::ASTSourceDescriptor(const Module &M)
+ASTSourceDescriptor::ASTSourceDescriptor(Module &M)
     : Signature(M.Signature), ClangModule(&M) {
   if (M.Directory)
     Path = M.Directory->getName();
Index: clang/lib/Serialization/ASTReader.cpp
===================================================================
--- clang/lib/Serialization/ASTReader.cpp
+++ clang/lib/Serialization/ASTReader.cpp
@@ -8493,7 +8493,7 @@
 
 llvm::Optional<ASTSourceDescriptor>
 ASTReader::getSourceDescriptor(unsigned ID) {
-  if (const Module *M = getSubmodule(ID))
+  if (Module *M = getSubmodule(ID))
     return ASTSourceDescriptor(*M);
 
   // If there is only a single PCH, return it instead.