diff --git a/include/llvm/DebugInfo/CodeView/ModuleDebugFileChecksumFragment.h b/include/llvm/DebugInfo/CodeView/ModuleDebugFileChecksumFragment.h
index b28f3fbef8c..98e6a54cf82 100644
--- a/include/llvm/DebugInfo/CodeView/ModuleDebugFileChecksumFragment.h
+++ b/include/llvm/DebugInfo/CodeView/ModuleDebugFileChecksumFragment.h
@@ -1,4 +1,4 @@
-//===- ModuleDebugLineFragment.h --------------------------------*- C++ -*-===//
+//===- ModuleDebugFileChecksumFragment.h ------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -39,15 +39,15 @@ public:
 
 namespace llvm {
 namespace codeview {
-class ModuleDebugFileChecksumFragment final : public ModuleDebugFragment {
-  typedef VarStreamArray<FileChecksumEntry> FileChecksumArray;
+class ModuleDebugFileChecksumFragmentRef final : public ModuleDebugFragmentRef {
+  typedef VarStreamArray<codeview::FileChecksumEntry> FileChecksumArray;
   typedef FileChecksumArray::Iterator Iterator;
 
 public:
-  ModuleDebugFileChecksumFragment()
-      : ModuleDebugFragment(ModuleDebugFragmentKind::FileChecksums) {}
+  ModuleDebugFileChecksumFragmentRef()
+      : ModuleDebugFragmentRef(ModuleDebugFragmentKind::FileChecksums) {}
 
-  static bool classof(const ModuleDebugFragment *S) {
+  static bool classof(const ModuleDebugFragmentRef *S) {
     return S->kind() == ModuleDebugFragmentKind::FileChecksums;
   }
 
diff --git a/include/llvm/DebugInfo/CodeView/ModuleDebugFragment.h b/include/llvm/DebugInfo/CodeView/ModuleDebugFragment.h
index 98d587f6521..f8b60c094ce 100644
--- a/include/llvm/DebugInfo/CodeView/ModuleDebugFragment.h
+++ b/include/llvm/DebugInfo/CodeView/ModuleDebugFragment.h
@@ -16,11 +16,11 @@
 namespace llvm {
 namespace codeview {
 
-class ModuleDebugFragment {
+class ModuleDebugFragmentRef {
 public:
-  explicit ModuleDebugFragment(ModuleDebugFragmentKind Kind) : Kind(Kind) {}
+  explicit ModuleDebugFragmentRef(ModuleDebugFragmentKind Kind) : Kind(Kind) {}
+  virtual ~ModuleDebugFragmentRef();
 
-  virtual ~ModuleDebugFragment();
   ModuleDebugFragmentKind kind() const { return Kind; }
 
 protected:
diff --git a/include/llvm/DebugInfo/CodeView/ModuleDebugFragmentVisitor.h b/include/llvm/DebugInfo/CodeView/ModuleDebugFragmentVisitor.h
index bcde565f6de..90da3e03a15 100644
--- a/include/llvm/DebugInfo/CodeView/ModuleDebugFragmentVisitor.h
+++ b/include/llvm/DebugInfo/CodeView/ModuleDebugFragmentVisitor.h
@@ -17,24 +17,25 @@ namespace llvm {
 
 namespace codeview {
 
-class ModuleDebugFileChecksumFragment;
+class ModuleDebugFileChecksumFragmentRef;
 class ModuleDebugFragmentRecord;
-class ModuleDebugInlineeLineFragment;
-class ModuleDebugLineFragment;
-class ModuleDebugUnknownFragment;
+class ModuleDebugInlineeLineFragmentRef;
+class ModuleDebugLineFragmentRef;
+class ModuleDebugUnknownFragmentRef;
 
 class ModuleDebugFragmentVisitor {
 public:
   virtual ~ModuleDebugFragmentVisitor() = default;
 
-  virtual Error visitUnknown(ModuleDebugUnknownFragment &Unknown) {
+  virtual Error visitUnknown(ModuleDebugUnknownFragmentRef &Unknown) {
     return Error::success();
   }
-  virtual Error visitLines(ModuleDebugLineFragment &Lines) {
+  virtual Error visitLines(ModuleDebugLineFragmentRef &Lines) {
     return Error::success();
   }
 
-  virtual Error visitFileChecksums(ModuleDebugFileChecksumFragment &Checksums) {
+  virtual Error
+  visitFileChecksums(ModuleDebugFileChecksumFragmentRef &Checksums) {
     return Error::success();
   }
 
diff --git a/include/llvm/DebugInfo/CodeView/ModuleDebugLineFragment.h b/include/llvm/DebugInfo/CodeView/ModuleDebugLineFragment.h
index 8b6ae6408a9..6268349d21b 100644
--- a/include/llvm/DebugInfo/CodeView/ModuleDebugLineFragment.h
+++ b/include/llvm/DebugInfo/CodeView/ModuleDebugLineFragment.h
@@ -63,15 +63,15 @@ public:
                        LineColumnEntry &Item, const LineFragmentHeader *Header);
 };
 
-class ModuleDebugLineFragment final : public ModuleDebugFragment {
+class ModuleDebugLineFragmentRef final : public ModuleDebugFragmentRef {
   friend class LineColumnExtractor;
   typedef VarStreamArray<LineColumnEntry, LineColumnExtractor> LineInfoArray;
   typedef LineInfoArray::Iterator Iterator;
 
 public:
-  ModuleDebugLineFragment();
+  ModuleDebugLineFragmentRef();
 
-  static bool classof(const ModuleDebugFragment *S) {
+  static bool classof(const ModuleDebugFragmentRef *S) {
     return S->kind() == ModuleDebugFragmentKind::Lines;
   }
 
diff --git a/include/llvm/DebugInfo/CodeView/ModuleDebugUnknownFragment.h b/include/llvm/DebugInfo/CodeView/ModuleDebugUnknownFragment.h
index bb764b6ea66..b8c1c02e5cf 100644
--- a/include/llvm/DebugInfo/CodeView/ModuleDebugUnknownFragment.h
+++ b/include/llvm/DebugInfo/CodeView/ModuleDebugUnknownFragment.h
@@ -16,10 +16,11 @@
 namespace llvm {
 namespace codeview {
 
-class ModuleDebugUnknownFragment final : public ModuleDebugFragment {
+class ModuleDebugUnknownFragmentRef final : public ModuleDebugFragmentRef {
 public:
-  ModuleDebugUnknownFragment(ModuleDebugFragmentKind Kind, BinaryStreamRef Data)
-      : ModuleDebugFragment(Kind), Data(Data) {}
+  ModuleDebugUnknownFragmentRef(ModuleDebugFragmentKind Kind,
+                                BinaryStreamRef Data)
+      : ModuleDebugFragmentRef(Kind), Data(Data) {}
 
   BinaryStreamRef getData() const { return Data; }
 
diff --git a/include/llvm/DebugInfo/PDB/Native/ModuleDebugStream.h b/include/llvm/DebugInfo/PDB/Native/ModuleDebugStream.h
index 2093691c453..2c95690ed58 100644
--- a/include/llvm/DebugInfo/PDB/Native/ModuleDebugStream.h
+++ b/include/llvm/DebugInfo/PDB/Native/ModuleDebugStream.h
@@ -24,14 +24,14 @@ namespace pdb {
 class PDBFile;
 class DbiModuleDescriptor;
 
-class ModuleDebugStream {
+class ModuleDebugStreamRef {
   typedef codeview::ModuleDebugFragmentArray::Iterator
       LinesAndChecksumsIterator;
 
 public:
-  ModuleDebugStream(const DbiModuleDescriptor &Module,
-                    std::unique_ptr<msf::MappedBlockStream> Stream);
-  ~ModuleDebugStream();
+  ModuleDebugStreamRef(const DbiModuleDescriptor &Module,
+                       std::unique_ptr<msf::MappedBlockStream> Stream);
+  ~ModuleDebugStreamRef();
 
   Error reload();
 
@@ -54,7 +54,7 @@ private:
   std::unique_ptr<msf::MappedBlockStream> Stream;
 
   codeview::CVSymbolArray SymbolsSubstream;
-  BinaryStreamRef LinesSubstream;
+  BinaryStreamRef C11LinesSubstream;
   BinaryStreamRef C13LinesSubstream;
   BinaryStreamRef GlobalRefsSubstream;
 
diff --git a/lib/DebugInfo/CodeView/ModuleDebugFileChecksumFragment.cpp b/lib/DebugInfo/CodeView/ModuleDebugFileChecksumFragment.cpp
index 3f234adc1c2..4bbfe285423 100644
--- a/lib/DebugInfo/CodeView/ModuleDebugFileChecksumFragment.cpp
+++ b/lib/DebugInfo/CodeView/ModuleDebugFileChecksumFragment.cpp
@@ -41,7 +41,8 @@ Error llvm::VarStreamArrayExtractor<FileChecksumEntry>::extract(
   return Error::success();
 }
 
-Error ModuleDebugFileChecksumFragment::initialize(BinaryStreamReader Reader) {
+Error ModuleDebugFileChecksumFragmentRef::initialize(
+    BinaryStreamReader Reader) {
   if (auto EC = Reader.readArray(Checksums, Reader.bytesRemaining()))
     return EC;
 
diff --git a/lib/DebugInfo/CodeView/ModuleDebugFragment.cpp b/lib/DebugInfo/CodeView/ModuleDebugFragment.cpp
index a3327b06b98..36f86cbbdf6 100644
--- a/lib/DebugInfo/CodeView/ModuleDebugFragment.cpp
+++ b/lib/DebugInfo/CodeView/ModuleDebugFragment.cpp
@@ -11,4 +11,4 @@
 
 using namespace llvm::codeview;
 
-ModuleDebugFragment::~ModuleDebugFragment() {}
+ModuleDebugFragmentRef::~ModuleDebugFragmentRef() {}
diff --git a/lib/DebugInfo/CodeView/ModuleDebugFragmentVisitor.cpp b/lib/DebugInfo/CodeView/ModuleDebugFragmentVisitor.cpp
index ce1d8d918b2..b7a86ee6699 100644
--- a/lib/DebugInfo/CodeView/ModuleDebugFragmentVisitor.cpp
+++ b/lib/DebugInfo/CodeView/ModuleDebugFragmentVisitor.cpp
@@ -24,21 +24,21 @@ Error llvm::codeview::visitModuleDebugFragment(
   BinaryStreamReader Reader(R.getRecordData());
   switch (R.kind()) {
   case ModuleDebugFragmentKind::Lines: {
-    ModuleDebugLineFragment Fragment;
+    ModuleDebugLineFragmentRef Fragment;
     if (auto EC = Fragment.initialize(Reader))
       return EC;
 
     return V.visitLines(Fragment);
   }
   case ModuleDebugFragmentKind::FileChecksums: {
-    ModuleDebugFileChecksumFragment Fragment;
+    ModuleDebugFileChecksumFragmentRef Fragment;
     if (auto EC = Fragment.initialize(Reader))
       return EC;
 
     return V.visitFileChecksums(Fragment);
   }
   default: {
-    ModuleDebugUnknownFragment Fragment(R.kind(), R.getRecordData());
+    ModuleDebugUnknownFragmentRef Fragment(R.kind(), R.getRecordData());
     return V.visitUnknown(Fragment);
   }
   }
diff --git a/lib/DebugInfo/CodeView/ModuleDebugLineFragment.cpp b/lib/DebugInfo/CodeView/ModuleDebugLineFragment.cpp
index d25be2d02d8..6a9751c1257 100644
--- a/lib/DebugInfo/CodeView/ModuleDebugLineFragment.cpp
+++ b/lib/DebugInfo/CodeView/ModuleDebugLineFragment.cpp
@@ -47,10 +47,10 @@ Error LineColumnExtractor::extract(BinaryStreamRef Stream, uint32_t &Len,
   return Error::success();
 }
 
-ModuleDebugLineFragment::ModuleDebugLineFragment()
-    : ModuleDebugFragment(ModuleDebugFragmentKind::Lines) {}
+ModuleDebugLineFragmentRef::ModuleDebugLineFragmentRef()
+    : ModuleDebugFragmentRef(ModuleDebugFragmentKind::Lines) {}
 
-Error ModuleDebugLineFragment::initialize(BinaryStreamReader Reader) {
+Error ModuleDebugLineFragmentRef::initialize(BinaryStreamReader Reader) {
   if (auto EC = Reader.readObject(Header))
     return EC;
 
@@ -61,6 +61,6 @@ Error ModuleDebugLineFragment::initialize(BinaryStreamReader Reader) {
   return Error::success();
 }
 
-bool ModuleDebugLineFragment::hasColumnInfo() const {
-  return Header->Flags & LF_HaveColumns;
+bool ModuleDebugLineFragmentRef::hasColumnInfo() const {
+  return !!(Header->Flags & LF_HaveColumns);
 }
diff --git a/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp b/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp
index 5e719c6179a..d7a203746a0 100644
--- a/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp
+++ b/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp
@@ -25,13 +25,14 @@ using namespace llvm::codeview;
 using namespace llvm::msf;
 using namespace llvm::pdb;
 
-ModuleDebugStream::ModuleDebugStream(const DbiModuleDescriptor &Module,
-                                     std::unique_ptr<MappedBlockStream> Stream)
+ModuleDebugStreamRef::ModuleDebugStreamRef(
+    const DbiModuleDescriptor &Module,
+    std::unique_ptr<MappedBlockStream> Stream)
     : Mod(Module), Stream(std::move(Stream)) {}
 
-ModuleDebugStream::~ModuleDebugStream() = default;
+ModuleDebugStreamRef::~ModuleDebugStreamRef() = default;
 
-Error ModuleDebugStream::reload() {
+Error ModuleDebugStreamRef::reload() {
   BinaryStreamReader Reader(*Stream);
 
   uint32_t SymbolSize = Mod.getSymbolDebugInfoByteSize();
@@ -49,7 +50,7 @@ Error ModuleDebugStream::reload() {
   if (auto EC = Reader.readArray(SymbolsSubstream, SymbolSize - 4))
     return EC;
 
-  if (auto EC = Reader.readStreamRef(LinesSubstream, C11Size))
+  if (auto EC = Reader.readStreamRef(C11LinesSubstream, C11Size))
     return EC;
   if (auto EC = Reader.readStreamRef(C13LinesSubstream, C13Size))
     return EC;
@@ -72,17 +73,17 @@ Error ModuleDebugStream::reload() {
 }
 
 iterator_range<codeview::CVSymbolArray::Iterator>
-ModuleDebugStream::symbols(bool *HadError) const {
+ModuleDebugStreamRef::symbols(bool *HadError) const {
   return make_range(SymbolsSubstream.begin(HadError), SymbolsSubstream.end());
 }
 
-llvm::iterator_range<ModuleDebugStream::LinesAndChecksumsIterator>
-ModuleDebugStream::linesAndChecksums() const {
+llvm::iterator_range<ModuleDebugStreamRef::LinesAndChecksumsIterator>
+ModuleDebugStreamRef::linesAndChecksums() const {
   return make_range(LinesAndChecksums.begin(), LinesAndChecksums.end());
 }
 
-bool ModuleDebugStream::hasLineInfo() const {
+bool ModuleDebugStreamRef::hasLineInfo() const {
   return C13LinesSubstream.getLength() > 0;
 }
 
-Error ModuleDebugStream::commit() { return Error::success(); }
+Error ModuleDebugStreamRef::commit() { return Error::success(); }
diff --git a/tools/llvm-pdbdump/C13DebugFragmentVisitor.cpp b/tools/llvm-pdbdump/C13DebugFragmentVisitor.cpp
index b4e64bf634d..940b38c4a8c 100644
--- a/tools/llvm-pdbdump/C13DebugFragmentVisitor.cpp
+++ b/tools/llvm-pdbdump/C13DebugFragmentVisitor.cpp
@@ -24,19 +24,19 @@ C13DebugFragmentVisitor::C13DebugFragmentVisitor(PDBFile &F) : F(F) {}
 C13DebugFragmentVisitor::~C13DebugFragmentVisitor() {}
 
 Error C13DebugFragmentVisitor::visitUnknown(
-    codeview::ModuleDebugUnknownFragment &Fragment) {
+    codeview::ModuleDebugUnknownFragmentRef &Fragment) {
   return Error::success();
 }
 
 Error C13DebugFragmentVisitor::visitFileChecksums(
-    codeview::ModuleDebugFileChecksumFragment &Checksums) {
+    codeview::ModuleDebugFileChecksumFragmentRef &Checksums) {
   assert(!this->Checksums.hasValue());
   this->Checksums = Checksums;
   return Error::success();
 }
 
 Error C13DebugFragmentVisitor::visitLines(
-    codeview::ModuleDebugLineFragment &Lines) {
+    codeview::ModuleDebugLineFragmentRef &Lines) {
   this->Lines.push_back(Lines);
   return Error::success();
 }
diff --git a/tools/llvm-pdbdump/C13DebugFragmentVisitor.h b/tools/llvm-pdbdump/C13DebugFragmentVisitor.h
index e4a51ce2adc..f0a536c6adc 100644
--- a/tools/llvm-pdbdump/C13DebugFragmentVisitor.h
+++ b/tools/llvm-pdbdump/C13DebugFragmentVisitor.h
@@ -28,12 +28,12 @@ public:
   C13DebugFragmentVisitor(PDBFile &F);
   ~C13DebugFragmentVisitor();
 
-  Error visitUnknown(codeview::ModuleDebugUnknownFragment &Fragment) final;
+  Error visitUnknown(codeview::ModuleDebugUnknownFragmentRef &Fragment) final;
 
   Error visitFileChecksums(
-      codeview::ModuleDebugFileChecksumFragment &Checksums) final;
+      codeview::ModuleDebugFileChecksumFragmentRef &Checksums) final;
 
-  Error visitLines(codeview::ModuleDebugLineFragment &Lines) final;
+  Error visitLines(codeview::ModuleDebugLineFragmentRef &Lines) final;
 
   Error finished() final;
 
@@ -44,8 +44,8 @@ protected:
   Expected<StringRef> getNameFromStringTable(uint32_t Offset);
   Expected<StringRef> getNameFromChecksumsBuffer(uint32_t Offset);
 
-  Optional<codeview::ModuleDebugFileChecksumFragment> Checksums;
-  std::vector<codeview::ModuleDebugLineFragment> Lines;
+  Optional<codeview::ModuleDebugFileChecksumFragmentRef> Checksums;
+  std::vector<codeview::ModuleDebugLineFragmentRef> Lines;
 
   PDBFile &F;
 };
diff --git a/tools/llvm-pdbdump/LLVMOutputStyle.cpp b/tools/llvm-pdbdump/LLVMOutputStyle.cpp
index 8ed1a9020c4..eec0793e2dd 100644
--- a/tools/llvm-pdbdump/LLVMOutputStyle.cpp
+++ b/tools/llvm-pdbdump/LLVMOutputStyle.cpp
@@ -80,8 +80,6 @@ struct PageStats {
   BitVector UseAfterFreePages;
 };
 
-// Define a locally scoped visitor to print the different
-// substream types types.
 class C13RawVisitor : public C13DebugFragmentVisitor {
 public:
   C13RawVisitor(ScopedPrinter &P, PDBFile &F)
@@ -723,7 +721,7 @@ Error LLVMOutputStyle::dumpDbiStream() {
             File.getMsfLayout(), File.getMsfBuffer(),
             Modi.Info.getModuleStreamIndex());
 
-        ModuleDebugStream ModS(Modi.Info, std::move(ModStreamData));
+        ModuleDebugStreamRef ModS(Modi.Info, std::move(ModStreamData));
         if (auto EC = ModS.reload())
           return EC;
 
@@ -751,7 +749,6 @@ Error LLVMOutputStyle::dumpDbiStream() {
         if (opts::raw::DumpLineInfo) {
           ListScope SS(P, "LineInfo");
 
-          // Inlinee Line Type Indices refer to the IPI stream.
           C13RawVisitor V(P, File);
           if (auto EC = codeview::visitModuleDebugFragments(
                   ModS.linesAndChecksums(), V))
diff --git a/tools/llvm-pdbdump/YAMLOutputStyle.cpp b/tools/llvm-pdbdump/YAMLOutputStyle.cpp
index a3fff552547..770d227e553 100644
--- a/tools/llvm-pdbdump/YAMLOutputStyle.cpp
+++ b/tools/llvm-pdbdump/YAMLOutputStyle.cpp
@@ -157,7 +157,7 @@ private:
 }
 
 Expected<Optional<llvm::pdb::yaml::PdbSourceFileInfo>>
-YAMLOutputStyle::getFileLineInfo(const pdb::ModuleDebugStream &ModS) {
+YAMLOutputStyle::getFileLineInfo(const pdb::ModuleDebugStreamRef &ModS) {
   if (!ModS.hasLineInfo())
     return None;
 
@@ -286,9 +286,10 @@ Error YAMLOutputStyle::dumpDbiStream() {
         continue;
 
       auto ModStreamData = msf::MappedBlockStream::createIndexedStream(
-          File.getMsfLayout(), File.getMsfBuffer(), ModiStream);
+          File.getMsfLayout(), File.getMsfBuffer(),
+          MI.Info.getModuleStreamIndex());
 
-      pdb::ModuleDebugStream ModS(MI.Info, std::move(ModStreamData));
+      pdb::ModuleDebugStreamRef ModS(MI.Info, std::move(ModStreamData));
       if (auto EC = ModS.reload())
         return EC;
 
diff --git a/tools/llvm-pdbdump/YAMLOutputStyle.h b/tools/llvm-pdbdump/YAMLOutputStyle.h
index 0918ca46c71..517c7d86d7a 100644
--- a/tools/llvm-pdbdump/YAMLOutputStyle.h
+++ b/tools/llvm-pdbdump/YAMLOutputStyle.h
@@ -19,7 +19,7 @@
 
 namespace llvm {
 namespace pdb {
-class ModuleDebugStream;
+class ModuleDebugStreamRef;
 
 class YAMLOutputStyle : public OutputStyle {
 public:
@@ -29,7 +29,7 @@ public:
 
 private:
   Expected<Optional<llvm::pdb::yaml::PdbSourceFileInfo>>
-  getFileLineInfo(const pdb::ModuleDebugStream &ModS);
+  getFileLineInfo(const pdb::ModuleDebugStreamRef &ModS);
 
   Error dumpStringTable();
   Error dumpFileHeaders();
diff --git a/tools/llvm-pdbdump/fuzzer/llvm-pdbdump-fuzzer.cpp b/tools/llvm-pdbdump/fuzzer/llvm-pdbdump-fuzzer.cpp
index b6688669c65..14cd222d138 100644
--- a/tools/llvm-pdbdump/fuzzer/llvm-pdbdump-fuzzer.cpp
+++ b/tools/llvm-pdbdump/fuzzer/llvm-pdbdump-fuzzer.cpp
@@ -90,7 +90,7 @@ extern "C" int LLVMFuzzerTestOneInput(uint8_t *data, size_t size) {
       consumeError(ModStreamData.takeError());
       return 0;
     }
-    pdb::ModuleDebugStream ModS(Modi.Info, std::move(*ModStreamData));
+    pdb::ModuleDebugStreamRef ModS(Modi.Info, std::move(*ModStreamData));
     if (auto E = ModS.reload()) {
       consumeError(std::move(E));
       return 0;
diff --git a/tools/llvm-readobj/COFFDumper.cpp b/tools/llvm-readobj/COFFDumper.cpp
index f744e8dac56..abe0e8d6965 100644
--- a/tools/llvm-readobj/COFFDumper.cpp
+++ b/tools/llvm-readobj/COFFDumper.cpp
@@ -897,7 +897,7 @@ void COFFDumper::printCodeViewSymbolSection(StringRef SectionName,
     BinaryByteStream LineTableInfo(FunctionLineTables[Name], support::little);
     BinaryStreamReader Reader(LineTableInfo);
 
-    ModuleDebugLineFragment LineInfo;
+    ModuleDebugLineFragmentRef LineInfo;
     error(LineInfo.initialize(Reader));
 
     W.printHex("Flags", LineInfo.header()->Flags);
@@ -964,7 +964,7 @@ void COFFDumper::printCodeViewSymbolsSubsection(StringRef Subsection,
 void COFFDumper::printCodeViewFileChecksums(StringRef Subsection) {
   BinaryByteStream S(Subsection, llvm::support::little);
   BinaryStreamReader SR(S);
-  ModuleDebugFileChecksumFragment Checksums;
+  ModuleDebugFileChecksumFragmentRef Checksums;
   error(Checksums.initialize(SR));
 
   for (auto &FC : Checksums) {