[clang] Add [is|set]Nested methods to NamespaceDecl

[njames93]

Summary

Adds support for NamespaceDecl to inform if its part of a nested namespace.
This flag only corresponds to the inner namespaces in a nested namespace declaration.
In this example:
namespace <X>::<Y>::<Z> {}
Only <Y> and <Z> will be classified as nested.

This flag isn't meant for assisting in building the AST, more for static analysis and refactorings.

[Mordante]

Just a few minor nits. I'll leave the approving to the other reviewers.

clang/lib/AST/TextNodeDumper.cpp

1828

Can you also modify JSONNodeDumper::VisitNamespaceDecl ?

clang/lib/Sema/SemaDeclCXX.cpp

11169

Please change false to /*Nested=*/false.

[shafik]

clang/lib/AST/ASTContext.cpp

7866

As noted elsewhere instead of just false please use /*Nested*/ false

Also a little below.

[njames93]

Added JsonNodeDumper and argument comments.

[Mordante]

In D90568#2370079, @njames93 wrote:

Added JsonNodeDumper and argument comments.

Thanks, I've no further comments.

[njames93]

Ping?

[njames93]

Ping?

[njames93]

Rebased
Changed logic so inner namespaces are marked as nester(which makes much more sense imo)

[njames93]

Fix clang-format

[aaron.ballman]

Generally LGTM, though I found a few minor things.

clang/include/clang/AST/Decl.h

516

I'm not really loving the F_ prefixes -- the enumerators are already privately scoped to NamespaceDecl, is that not sufficient protection?

clang/lib/AST/DeclCXX.cpp

2852

I love it and hate it in equal measures; I think multiplying a bool and an enumerator together is just a bit too clever. How about:

unsigned Flags = 0;
if (Inline) Flags |= F_Inline;
if (Nested) Flags |= F_Nested;
AnonOrFirstNamespaceAndFlags(nullptr, Flags);

It's longer, but I think it's also more clear.

clang/lib/AST/ItaniumMangle.cpp

602–607 ↗

(On Diff #473457)

Not your problem, but I'm curious if you agree: we should probably have a helper method for getting the std namespace (and creating it if necessary) so we don't do this dance in at least three different places.

[njames93]

Clean up initializer.

[shafik]

clang/lib/AST/ASTContext.cpp

7860–7866

Overriding my old comment from a while ago,

8053–8055

clang/lib/AST/ItaniumMangle.cpp

605–607 ↗

(On Diff #473810)

clang/lib/Sema/HLSLExternalSemaSource.cpp

386 ↗

(On Diff #473810)

[njames93]

Fix comments.

clang/include/clang/AST/Decl.h

516

I think just having it named as Inline and Nested is going to confuse things even more, BlockDecl seems to use flag_is<FLAG> for its packing, and I think that is even worse. WDYT

[njames93]

clang/test/AST/ast-dump-decl.cpp

1–823

This is confusing me, I'm not sure exactly why this file appears to have been complete changed when it doesn't appear to, CL/LF maybe?

[aaron.ballman]

clang/include/clang/AST/Decl.h

516

Eh, I don't feel super strongly, but if you want to force there to be a qualified name, then I'd hoist it out of NamespaceDecl and make a scoped enum so you can write Namespace::Inline or Namespace::Nested.

clang/test/AST/ast-dump-decl.cpp

1–823

Yeah this looks like a line ending change slipped in because Phab is showing green/red on lines with no visible modifications. FWIW, my local copy seems to be using UNIX line endings and not Windows line endings.

[njames93]

Hopefully fixed line endings

[thakis]

This breaks the build: http://45.33.8.238/linux/92294/step_4.txt

Please take a look and revert for now if it takes a while to fix.

[njames93]

In D90568#3949134, @thakis wrote:

This breaks the build: http://45.33.8.238/linux/92294/step_4.txt

Please take a look and revert for now if it takes a while to fix.

Apologies it took 2 times, It should all be good now, lmk if there's any other issues.

[thakis]

My bots look happy at least. Thanks for the quick fix!

clang/include/clang/AST/Decl.h

public:
   static bool classof(const Decl *D) { return classofKind(D->getKind()); }
   static bool classofKind(Kind K) { return K == Label; }
 };
 
 /// Represent a C++ namespace.
 class NamespaceDecl : public NamedDecl, public DeclContext,
                       public Redeclarable<NamespaceDecl>
 {
+
+  enum Flags : unsigned { F_Inline = 1 << 0, F_Nested = 1 << 1 };
+
   /// The starting location of the source range, pointing
   /// to either the namespace or the inline keyword.
   SourceLocation LocStart;
 
   /// The ending location of the source range.
   SourceLocation RBraceLoc;
 
   /// A pointer to either the anonymous namespace that lives just inside
   /// this namespace or to the first namespace in the chain (the latter case
   /// only when this is not the first in the chain), along with a
   /// boolean value indicating whether this is an inline namespace.
-  llvm::PointerIntPair<NamespaceDecl *, 1, bool> AnonOrFirstNamespaceAndInline;
+  llvm::PointerIntPair<NamespaceDecl *, 2, unsigned>
+      AnonOrFirstNamespaceAndFlags;
 
   NamespaceDecl(ASTContext &C, DeclContext *DC, bool Inline,
                 SourceLocation StartLoc, SourceLocation IdLoc,
-                IdentifierInfo *Id, NamespaceDecl *PrevDecl);
+                IdentifierInfo *Id, NamespaceDecl *PrevDecl, bool Nested);
 
   using redeclarable_base = Redeclarable<NamespaceDecl>;
 
   NamespaceDecl *getNextRedeclarationImpl() override;
   NamespaceDecl *getPreviousDeclImpl() override;
   NamespaceDecl *getMostRecentDeclImpl() override;
 
 public:
   friend class ASTDeclReader;
   friend class ASTDeclWriter;
 
-  static NamespaceDecl *Create(ASTContext &C, DeclContext *DC,
-                               bool Inline, SourceLocation StartLoc,
-                               SourceLocation IdLoc, IdentifierInfo *Id,
-                               NamespaceDecl *PrevDecl);
+  static NamespaceDecl *Create(ASTContext &C, DeclContext *DC, bool Inline,
+                               SourceLocation StartLoc, SourceLocation IdLoc,
+                               IdentifierInfo *Id, NamespaceDecl *PrevDecl,
+                               bool Nested);
 
   static NamespaceDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
   using redecl_range = redeclarable_base::redecl_range;
   using redecl_iterator = redeclarable_base::redecl_iterator;
 
   using redeclarable_base::redecls_begin;
   using redeclarable_base::redecls_end;
public:
   /// \endcode
   /// q.v. C++ [namespace.unnamed]
   bool isAnonymousNamespace() const {
     return !getIdentifier();
   }
 
   /// Returns true if this is an inline namespace declaration.
   bool isInline() const {
-    return AnonOrFirstNamespaceAndInline.getInt();
+    return AnonOrFirstNamespaceAndFlags.getInt() & F_Inline;
   }
 
   /// Set whether this is an inline namespace declaration.
   void setInline(bool Inline) {
-    AnonOrFirstNamespaceAndInline.setInt(Inline);
+    unsigned F = AnonOrFirstNamespaceAndFlags.getInt();
+    if (Inline)
+      AnonOrFirstNamespaceAndFlags.setInt(F | F_Inline);
+    else
+      AnonOrFirstNamespaceAndFlags.setInt(F & ~F_Inline);
+  }
+
+  bool isNested() const {
+    return AnonOrFirstNamespaceAndFlags.getInt() & F_Nested;
+  }
+
+  void setNested(bool Nested) {
+    unsigned F = AnonOrFirstNamespaceAndFlags.getInt();
+    if (Nested)
+      AnonOrFirstNamespaceAndFlags.setInt(F | F_Nested);
+    else
+      AnonOrFirstNamespaceAndFlags.setInt(F & ~F_Nested);
   }
 
   /// Get the original (first) namespace declaration.
   NamespaceDecl *getOriginalNamespace();
 
   /// Get the original (first) namespace declaration.
   const NamespaceDecl *getOriginalNamespace() const;
 
   /// Return true if this declaration is an original (first) declaration
   /// of the namespace. This is false for non-original (subsequent) namespace
   /// declarations and anonymous namespaces.
   bool isOriginalNamespace() const;
 
   /// Retrieve the anonymous namespace nested inside this namespace,
   /// if any.
   NamespaceDecl *getAnonymousNamespace() const {
-    return getOriginalNamespace()->AnonOrFirstNamespaceAndInline.getPointer();
+    return getOriginalNamespace()->AnonOrFirstNamespaceAndFlags.getPointer();
   }
 
   void setAnonymousNamespace(NamespaceDecl *D) {
-    getOriginalNamespace()->AnonOrFirstNamespaceAndInline.setPointer(D);
+    getOriginalNamespace()->AnonOrFirstNamespaceAndFlags.setPointer(D);
   }
 
   /// Retrieves the canonical declaration of this namespace.
   NamespaceDecl *getCanonicalDecl() override {
     return getOriginalNamespace();
   }
   const NamespaceDecl *getCanonicalDecl() const {
     return getOriginalNamespace();

clang/include/clang/Sema/Sema.h

public:
   //===---------------------------- C++ Features --------------------------===//
 
   // Act on C++ namespaces
   Decl *ActOnStartNamespaceDef(Scope *S, SourceLocation InlineLoc,
                                SourceLocation NamespaceLoc,
                                SourceLocation IdentLoc, IdentifierInfo *Ident,
                                SourceLocation LBrace,
                                const ParsedAttributesView &AttrList,
-                               UsingDirectiveDecl *&UsingDecl);
+                               UsingDirectiveDecl *&UsingDecl, bool IsNested);
   void ActOnFinishNamespaceDef(Decl *Dcl, SourceLocation RBrace);
 
   NamespaceDecl *getStdNamespace() const;
   NamespaceDecl *getOrCreateStdNamespace();
 
   NamespaceDecl *lookupStdExperimentalNamespace();
 
   CXXRecordDecl *getStdBadAlloc() const;

clang/lib/AST/ASTContext.cpp

static TypedefDecl *CreateVoidPtrBuiltinVaListDecl(const ASTContext *Context) {
   return Context->buildImplicitTypedef(T, "__builtin_va_list");
 }
 
 static TypedefDecl *
 CreateAArch64ABIBuiltinVaListDecl(const ASTContext *Context) {
   // struct __va_list
   RecordDecl *VaListTagDecl = Context->buildImplicitRecord("__va_list");
   if (Context->getLangOpts().CPlusPlus) {
     // namespace std { struct __va_list {
     NamespaceDecl *NS;
     NS = NamespaceDecl::Create(const_cast<ASTContext &>(*Context),
                                Context->getTranslationUnitDecl(),
                                /*Inline*/ false, SourceLocation(),
                                SourceLocation(), &Context->Idents.get("std"),
-                               /*PrevDecl*/ nullptr);
+                               /*PrevDecl*/ nullptr, /*Nested*/ false);
     NS->setImplicit();
     VaListTagDecl->setDeclContext(NS);
   }
 
   VaListTagDecl->startDefinition();
 
   const size_t NumFields = 5;
   QualType FieldTypes[NumFields];

 CreateAAPCSABIBuiltinVaListDecl(const ASTContext *Context) {
   // struct __va_list
   RecordDecl *VaListDecl = Context->buildImplicitRecord("__va_list");
   if (Context->getLangOpts().CPlusPlus) {
     // namespace std { struct __va_list {
     NamespaceDecl *NS;
     NS = NamespaceDecl::Create(const_cast<ASTContext &>(*Context),
                                Context->getTranslationUnitDecl(),
-                               /*Inline*/false, SourceLocation(),
+                               /*Inline*/ false, SourceLocation(),
                                SourceLocation(), &Context->Idents.get("std"),
-                               /*PrevDecl*/ nullptr);
+                               /*PrevDecl*/ nullptr, /*Nested*/ false);
     NS->setImplicit();
     VaListDecl->setDeclContext(NS);
   }
 
   VaListDecl->startDefinition();
 
   // void * __ap;
   FieldDecl *Field = FieldDecl::Create(const_cast<ASTContext &>(*Context),

clang/lib/AST/ASTImporter.cpp

if (!BeginLocOrErr)
     return BeginLocOrErr.takeError();
   ExpectedSLoc RBraceLocOrErr = import(D->getRBraceLoc());
   if (!RBraceLocOrErr)
     return RBraceLocOrErr.takeError();
 
   // Create the "to" namespace, if needed.
   NamespaceDecl *ToNamespace = MergeWithNamespace;
   if (!ToNamespace) {
-    if (GetImportedOrCreateDecl(
-            ToNamespace, D, Importer.getToContext(), DC, D->isInline(),
-            *BeginLocOrErr, Loc, Name.getAsIdentifierInfo(),
-            /*PrevDecl=*/nullptr))
+    if (GetImportedOrCreateDecl(ToNamespace, D, Importer.getToContext(), DC,
+                                D->isInline(), *BeginLocOrErr, Loc,
+                                Name.getAsIdentifierInfo(),
+                                /*PrevDecl=*/nullptr, D->isNested()))
       return ToNamespace;
     ToNamespace->setRBraceLoc(*RBraceLocOrErr);
     ToNamespace->setLexicalDeclContext(LexicalDC);
     LexicalDC->addDeclInternal(ToNamespace);
 
     // If this is an anonymous namespace, register it as the anonymous
     // namespace within its context.
     if (!Name) {

clang/lib/AST/DeclCXX.cpp

 NamespaceDecl *UsingDirectiveDecl::getNominatedNamespace() {
   if (auto *NA = dyn_cast_or_null<NamespaceAliasDecl>(NominatedNamespace))
     return NA->getNamespace();
   return cast_or_null<NamespaceDecl>(NominatedNamespace);
 }
 
 NamespaceDecl::NamespaceDecl(ASTContext &C, DeclContext *DC, bool Inline,
                              SourceLocation StartLoc, SourceLocation IdLoc,
-                             IdentifierInfo *Id, NamespaceDecl *PrevDecl)
+                             IdentifierInfo *Id, NamespaceDecl *PrevDecl,
+                             bool Nested)
     : NamedDecl(Namespace, DC, IdLoc, Id), DeclContext(Namespace),
       redeclarable_base(C), LocStart(StartLoc),
-      AnonOrFirstNamespaceAndInline(nullptr, Inline) {
+      AnonOrFirstNamespaceAndFlags(nullptr,
+                                   F_Inline * Inline | F_Nested * Nested) {
   setPreviousDecl(PrevDecl);
 
   if (PrevDecl)
-    AnonOrFirstNamespaceAndInline.setPointer(PrevDecl->getOriginalNamespace());
+    AnonOrFirstNamespaceAndFlags.setPointer(PrevDecl->getOriginalNamespace());
 }
 
 NamespaceDecl *NamespaceDecl::Create(ASTContext &C, DeclContext *DC,
                                      bool Inline, SourceLocation StartLoc,
                                      SourceLocation IdLoc, IdentifierInfo *Id,
-                                     NamespaceDecl *PrevDecl) {
-  return new (C, DC) NamespaceDecl(C, DC, Inline, StartLoc, IdLoc, Id,
-                                   PrevDecl);
+                                     NamespaceDecl *PrevDecl, bool Nested) {
+  return new (C, DC)
+      NamespaceDecl(C, DC, Inline, StartLoc, IdLoc, Id, PrevDecl, Nested);
 }
 
 NamespaceDecl *NamespaceDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
   return new (C, ID) NamespaceDecl(C, nullptr, false, SourceLocation(),
-                                   SourceLocation(), nullptr, nullptr);
+                                   SourceLocation(), nullptr, nullptr, false);
 }
 
 NamespaceDecl *NamespaceDecl::getOriginalNamespace() {
   if (isFirstDecl())
     return this;
 
-  return AnonOrFirstNamespaceAndInline.getPointer();
+  return AnonOrFirstNamespaceAndFlags.getPointer();
 }
 
 const NamespaceDecl *NamespaceDecl::getOriginalNamespace() const {
   if (isFirstDecl())
     return this;
 
-  return AnonOrFirstNamespaceAndInline.getPointer();
+  return AnonOrFirstNamespaceAndFlags.getPointer();
 }
 
 bool NamespaceDecl::isOriginalNamespace() const { return isFirstDecl(); }
 
 NamespaceDecl *NamespaceDecl::getNextRedeclarationImpl() {
   return getNextRedeclaration();
 }
 

clang/lib/AST/JSONNodeDumper.cpp

 void JSONNodeDumper::VisitTypeAliasDecl(const TypeAliasDecl *TAD) {
   VisitNamedDecl(TAD);
   JOS.attribute("type", createQualType(TAD->getUnderlyingType()));
 }
 
 void JSONNodeDumper::VisitNamespaceDecl(const NamespaceDecl *ND) {
   VisitNamedDecl(ND);
   attributeOnlyIfTrue("isInline", ND->isInline());
+  attributeOnlyIfTrue("isNested", ND->isNested());
   if (!ND->isOriginalNamespace())
     JOS.attribute("originalNamespace",
                   createBareDeclRef(ND->getOriginalNamespace()));
 }
 
 void JSONNodeDumper::VisitUsingDirectiveDecl(const UsingDirectiveDecl *UDD) {
   JOS.attribute("nominatedNamespace",
                 createBareDeclRef(UDD->getNominatedNamespace()));

clang/lib/AST/TextNodeDumper.cpp

void TextNodeDumper::VisitOMPCapturedExprDecl(const OMPCapturedExprDecl *D) {
   dumpName(D);
   dumpType(D->getType());
 }
 
 void TextNodeDumper::VisitNamespaceDecl(const NamespaceDecl *D) {
   dumpName(D);
   if (D->isInline())
     OS << " inline";
+  if (D->isNested())
+    OS << " nested";
   if (!D->isOriginalNamespace())
     dumpDeclRef(D->getOriginalNamespace(), "original");
 }
 
 void TextNodeDumper::VisitUsingDirectiveDecl(const UsingDirectiveDecl *D) {
   OS << ' ';
   dumpBareDeclRef(D->getNominatedNamespace());
 }

clang/lib/Parse/ParseDeclCXX.cpp

Diag(InlineLoc, getLangOpts().CPlusPlus11 ?
          diag::warn_cxx98_compat_inline_namespace : diag::ext_inline_namespace);
 
   // Enter a scope for the namespace.
   ParseScope NamespaceScope(this, Scope::DeclScope);
 
   UsingDirectiveDecl *ImplicitUsingDirectiveDecl = nullptr;
   Decl *NamespcDecl = Actions.ActOnStartNamespaceDef(
       getCurScope(), InlineLoc, NamespaceLoc, IdentLoc, Ident,
-      T.getOpenLocation(), attrs, ImplicitUsingDirectiveDecl);
+      T.getOpenLocation(), attrs, ImplicitUsingDirectiveDecl,
+      !ExtraNSs.empty());
 
   PrettyDeclStackTraceEntry CrashInfo(Actions.Context, NamespcDecl,
                                       NamespaceLoc, "parsing namespace");
 
   // Parse the contents of the namespace.  This includes parsing recovery on
   // any improperly nested namespaces.
   ParseInnerNamespace(ExtraNSs, 0, InlineLoc, attrs, T);
 
void Parser::ParseInnerNamespace(const InnerNamespaceInfoList &InnerNSs,
   // Handle a nested namespace definition.
   // FIXME: Preserve the source information through to the AST rather than
   // desugaring it here.
   ParseScope NamespaceScope(this, Scope::DeclScope);
   UsingDirectiveDecl *ImplicitUsingDirectiveDecl = nullptr;
   Decl *NamespcDecl = Actions.ActOnStartNamespaceDef(
       getCurScope(), InnerNSs[index].InlineLoc, InnerNSs[index].NamespaceLoc,
       InnerNSs[index].IdentLoc, InnerNSs[index].Ident,
-      Tracker.getOpenLocation(), attrs, ImplicitUsingDirectiveDecl);
+      Tracker.getOpenLocation(), attrs, ImplicitUsingDirectiveDecl,
+      index < InnerNSs.size() - 1);
   assert(!ImplicitUsingDirectiveDecl &&
          "nested namespace definition cannot define anonymous namespace");
 
   ParseInnerNamespace(InnerNSs, ++index, InlineLoc, attrs, Tracker);
 
   NamespaceScope.Exit();
   Actions.ActOnFinishNamespaceDef(NamespcDecl, Tracker.getCloseLocation());
 }

clang/lib/Sema/SemaDeclCXX.cpp

else
     S.Diag(Loc, diag::err_inline_namespace_mismatch);
 
   S.Diag(PrevNS->getLocation(), diag::note_previous_definition);
   *IsInline = PrevNS->isInline();
 }
 
 /// ActOnStartNamespaceDef - This is called at the start of a namespace
 /// definition.
-Decl *Sema::ActOnStartNamespaceDef(
-    Scope *NamespcScope, SourceLocation InlineLoc, SourceLocation NamespaceLoc,
-    SourceLocation IdentLoc, IdentifierInfo *II, SourceLocation LBrace,
-    const ParsedAttributesView &AttrList, UsingDirectiveDecl *&UD) {
+Decl *Sema::ActOnStartNamespaceDef(Scope *NamespcScope,
+                                   SourceLocation InlineLoc,
+                                   SourceLocation NamespaceLoc,
+                                   SourceLocation IdentLoc, IdentifierInfo *II,
+                                   SourceLocation LBrace,
+                                   const ParsedAttributesView &AttrList,
+                                   UsingDirectiveDecl *&UD, bool IsNested) {
   SourceLocation StartLoc = InlineLoc.isValid() ? InlineLoc : NamespaceLoc;
   // For anonymous namespace, take the location of the left brace.
   SourceLocation Loc = II ? IdentLoc : LBrace;
   bool IsInline = InlineLoc.isValid();
   bool IsInvalid = false;
   bool IsStd = false;
   bool AddToKnown = false;
   Scope *DeclRegionScope = NamespcScope->getParent();
if (TranslationUnitDecl *TU = dyn_cast<TranslationUnitDecl>(Parent)) {
       PrevNS = ND->getAnonymousNamespace();
     }
 
     if (PrevNS && IsInline != PrevNS->isInline())
       DiagnoseNamespaceInlineMismatch(*this, NamespaceLoc, NamespaceLoc, II,
                                       &IsInline, PrevNS);
   }
 
-  NamespaceDecl *Namespc = NamespaceDecl::Create(Context, CurContext, IsInline,
-                                                 StartLoc, Loc, II, PrevNS);
+  NamespaceDecl *Namespc = NamespaceDecl::Create(
+      Context, CurContext, IsInline, StartLoc, Loc, II, PrevNS, IsNested);
   if (IsInvalid)
     Namespc->setInvalidDecl();
 
   ProcessDeclAttributeList(DeclRegionScope, Namespc, AttrList);
   AddPragmaAttributes(DeclRegionScope, Namespc);
 
   // FIXME: Should we be merging attributes?
   if (const VisibilityAttr *Attr = Namespc->getAttr<VisibilityAttr>())
QualType Sema::CheckComparisonCategoryType(ComparisonCategoryType Kind,
   return Info->getType();
 }
 
 /// Retrieve the special "std" namespace, which may require us to
 /// implicitly define the namespace.
 NamespaceDecl *Sema::getOrCreateStdNamespace() {
   if (!StdNamespace) {
     // The "std" namespace has not yet been defined, so build one implicitly.
-    StdNamespace = NamespaceDecl::Create(Context,
-                                         Context.getTranslationUnitDecl(),
-                                         /*Inline=*/false,
-                                         SourceLocation(), SourceLocation(),
-                                         &PP.getIdentifierTable().get("std"),
-                                         /*PrevDecl=*/nullptr);
+    StdNamespace = NamespaceDecl::Create(
+        Context, Context.getTranslationUnitDecl(),
+        /*Inline=*/false, SourceLocation(), SourceLocation(),
+        /*PrevDecl=*/nullptr, /*Nested=*/false);
     getStdNamespace()->setImplicit(true);
   }
 
   return getStdNamespace();
 }
 
 bool Sema::isStdInitializerList(QualType Ty, QualType *Element) {
   assert(getLangOpts().CPlusPlus &&

clang/lib/Serialization/ASTReaderDecl.cpp

void ASTDeclReader::VisitLabelDecl(LabelDecl *D) {
   VisitNamedDecl(D);
   D->setLocStart(readSourceLocation());
 }
 
 void ASTDeclReader::VisitNamespaceDecl(NamespaceDecl *D) {
   RedeclarableResult Redecl = VisitRedeclarable(D);
   VisitNamedDecl(D);
   D->setInline(Record.readInt());
+  D->setNested(Record.readInt());
   D->LocStart = readSourceLocation();
   D->RBraceLoc = readSourceLocation();
 
   // Defer loading the anonymous namespace until we've finished merging
   // this namespace; loading it might load a later declaration of the
   // same namespace, and we have an invariant that older declarations
   // get merged before newer ones try to merge.
   GlobalDeclID AnonNamespace = 0;
   if (Redecl.getFirstID() == ThisDeclID) {
     AnonNamespace = readDeclID();
   } else {
     // Link this namespace back to the first declaration, which has already
     // been deserialized.
-    D->AnonOrFirstNamespaceAndInline.setPointer(D->getFirstDecl());
+    D->AnonOrFirstNamespaceAndFlags.setPointer(D->getFirstDecl());
   }
 
   mergeRedeclarable(D, Redecl);
 
   if (AnonNamespace) {
     // Each module has its own anonymous namespace, which is disjoint from
     // any other module's anonymous namespaces, so don't attach the anonymous
     // namespace at all.
if (ExistingCanon != DCanon) {
     D->First = ExistingCanon;
     ExistingCanon->Used |= D->Used;
     D->Used = false;
 
     // When we merge a namespace, update its pointer to the first namespace.
     // We cannot have loaded any redeclarations of this declaration yet, so
     // there's nothing else that needs to be updated.
     if (auto *Namespace = dyn_cast<NamespaceDecl>(D))
-      Namespace->AnonOrFirstNamespaceAndInline.setPointer(
-          assert_cast<NamespaceDecl*>(ExistingCanon));
+      Namespace->AnonOrFirstNamespaceAndFlags.setPointer(
+          assert_cast<NamespaceDecl *>(ExistingCanon));
 
     // When we merge a template, merge its pattern.
     if (auto *DTemplate = dyn_cast<RedeclarableTemplateDecl>(D))
       mergeTemplatePattern(
           DTemplate, assert_cast<RedeclarableTemplateDecl*>(ExistingCanon),
           TemplatePatternID, Redecl.isKeyDecl());
 
     // If this declaration is a key declaration, make a note of that.

clang/lib/Serialization/ASTWriterDecl.cpp

void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
   Code = serialization::DECL_LABEL;
 }
 
 
 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
   VisitRedeclarable(D);
   VisitNamedDecl(D);
   Record.push_back(D->isInline());
+  Record.push_back(D->isNested());
   Record.AddSourceLocation(D->getBeginLoc());
   Record.AddSourceLocation(D->getRBraceLoc());
 
   if (D->isOriginalNamespace())
     Record.AddDeclRef(D->getAnonymousNamespace());
   Code = serialization::DECL_NAMESPACE;
 
   if (Writer.hasChain() && D->isAnonymousNamespace() &&

clang/test/AST/ast-dump-decl.cpp

 // Test without serialization:
 // RUN: %clang_cc1 -std=c++11 -triple x86_64-linux-gnu -fms-extensions \
 // RUN: -ast-dump -ast-dump-filter Test %s \
 // RUN: | FileCheck --strict-whitespace %s
 //
 // Test with serialization: FIXME: Find why the outputs differs and fix it!
 //    : %clang_cc1 -std=c++11 -triple x86_64-linux-gnu -fms-extensions -emit-pch -o %t %s
 //    : %clang_cc1 -x c++ -std=c++11 -triple x86_64-linux-gnu -fms-extensions -include-pch %t \
 //    : -ast-dump-all -ast-dump-filter Test /dev/null \
 //    : | sed -e "s/ <undeserialized declarations>//" -e "s/ imported//" \
 //    : | FileCheck --strict-whitespace %s
 
 class testEnumDecl {
   enum class TestEnumDeclScoped;
   enum TestEnumDeclFixed : int;
 };
 // CHECK: EnumDecl{{.*}} class TestEnumDeclScoped 'int'
 // CHECK: EnumDecl{{.*}} TestEnumDeclFixed 'int'
 
 class testFieldDecl {
   int TestFieldDeclInit = 0;
 };
 // CHECK:      FieldDecl{{.*}} TestFieldDeclInit 'int'
 // CHECK-NEXT:   IntegerLiteral
 
 namespace testVarDeclNRVO {
   class A { };
   A foo() {
     A TestVarDeclNRVO;
     return TestVarDeclNRVO;
   }
 }
 // CHECK: VarDecl{{.*}} TestVarDeclNRVO 'testVarDeclNRVO::A' nrvo
 
 void testParmVarDeclInit(int TestParmVarDeclInit = 0);
 // CHECK:      ParmVarDecl{{.*}} TestParmVarDeclInit 'int'
 // CHECK-NEXT:   IntegerLiteral{{.*}}
 
 namespace TestNamespaceDecl {
   int i;
 }
 // CHECK:      NamespaceDecl{{.*}} TestNamespaceDecl
 // CHECK-NEXT:   VarDecl
 
 namespace TestNamespaceDecl {
   int j;
 }
 // CHECK:      NamespaceDecl{{.*}} TestNamespaceDecl
 // CHECK-NEXT:   original Namespace
 // CHECK-NEXT:   VarDecl
 
 inline namespace TestNamespaceDeclInline {
 }
 // CHECK:      NamespaceDecl{{.*}} TestNamespaceDeclInline inline
 
+namespace TestNestedNameSpace::Nested {
+}
+// CHECK:      NamespaceDecl{{.*}} TestNestedNameSpace nested
+// CHECK:      NamespaceDecl{{.*}} Nested{{\s*$}}
+
+namespace TestMultipleNested::SecondLevelNested::Nested {
+}
+// CHECK:      NamespaceDecl{{.*}} TestMultipleNested nested
+// CHECK:      NamespaceDecl{{.*}} SecondLevelNested nested
+// CHECK:      NamespaceDecl{{.*}} Nested{{\s*$}}
+
+namespace TestInlineNested::inline SecondLevel::inline Nested {
+}
+// CHECK:      NamespaceDecl{{.*}} TestInlineNested nested
+// CHECK:      NamespaceDecl{{.*}} SecondLevel inline nested
+// CHECK:      NamespaceDecl{{.*}} Nested inline{{\s*$}}
+
 namespace testUsingDirectiveDecl {
   namespace A {
   }
 }
 namespace TestUsingDirectiveDecl {
   using namespace testUsingDirectiveDecl::A;
 }
 // CHECK:      NamespaceDecl{{.*}} TestUsingDirectiveDecl
 // CHECK-NEXT:   UsingDirectiveDecl{{.*}} Namespace{{.*}} 'A'
 
 namespace testNamespaceAlias {
   namespace A {
   }
 }
 namespace TestNamespaceAlias = testNamespaceAlias::A;
 // CHECK:      NamespaceAliasDecl{{.*}} TestNamespaceAlias
 // CHECK-NEXT:   Namespace{{.*}} 'A'
 
 using TestTypeAliasDecl = int;
 // CHECK: TypeAliasDecl{{.*}} TestTypeAliasDecl 'int'
 
 namespace testTypeAliasTemplateDecl {
   template<typename T> class A;
   template<typename T> using TestTypeAliasTemplateDecl = A<T>;
 }
 // CHECK:      TypeAliasTemplateDecl{{.*}} TestTypeAliasTemplateDecl
 // CHECK-NEXT:   TemplateTypeParmDecl
 // CHECK-NEXT:   TypeAliasDecl{{.*}} TestTypeAliasTemplateDecl 'A<T>'
 
 namespace testCXXRecordDecl {
   class TestEmpty {};
 // CHECK:      CXXRecordDecl{{.*}} class TestEmpty
 // CHECK-NEXT:   DefinitionData pass_in_registers empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
 // CHECK-NEXT:     DefaultConstructor exists trivial constexpr
 // CHECK-NEXT:     CopyConstructor simple trivial has_const_param
 // CHECK-NEXT:     MoveConstructor exists simple trivial
 // CHECK-NEXT:     CopyAssignment simple trivial has_const_param
 // CHECK-NEXT:     MoveAssignment exists simple trivial
 // CHECK-NEXT:     Destructor simple irrelevant trivial
 
   class A { };
   class B { };
   class TestCXXRecordDecl : virtual A, public B {
     int i;
   };
 }
 // CHECK:      CXXRecordDecl{{.*}} class TestCXXRecordDecl
 // CHECK-NEXT:   DefinitionData{{$}}
 // CHECK-NEXT:     DefaultConstructor exists non_trivial
 // CHECK-NEXT:     CopyConstructor simple non_trivial has_const_param
 // CHECK-NEXT:     MoveConstructor exists simple non_trivial
 // CHECK-NEXT:     CopyAssignment simple non_trivial has_const_param
 // CHECK-NEXT:     MoveAssignment exists simple non_trivial
 // CHECK-NEXT:     Destructor simple irrelevant trivial
 // CHECK-NEXT:   virtual private 'testCXXRecordDecl::A'
 // CHECK-NEXT:   public 'testCXXRecordDecl::B'
 // CHECK-NEXT:   CXXRecordDecl{{.*}} class TestCXXRecordDecl
 // CHECK-NEXT:   FieldDecl
 
 template<class...T>
 class TestCXXRecordDeclPack : public T... {
 };
 // CHECK:      CXXRecordDecl{{.*}} class TestCXXRecordDeclPack
 // CHECK:        public 'T'...
 // CHECK-NEXT:   CXXRecordDecl{{.*}} class TestCXXRecordDeclPack
 
 thread_local int TestThreadLocalInt;
 // CHECK: TestThreadLocalInt {{.*}} tls_dynamic
 
 class testCXXMethodDecl {
   virtual void TestCXXMethodDeclPure() = 0;
   void TestCXXMethodDeclDelete() = delete;
   void TestCXXMethodDeclThrow() throw();
   void TestCXXMethodDeclThrowType() throw(int);
 };
 // CHECK: CXXMethodDecl{{.*}} TestCXXMethodDeclPure 'void ()' virtual pure
 // CHECK: CXXMethodDecl{{.*}} TestCXXMethodDeclDelete 'void ()' delete
 // CHECK: CXXMethodDecl{{.*}} TestCXXMethodDeclThrow 'void () throw()'
 // CHECK: CXXMethodDecl{{.*}} TestCXXMethodDeclThrowType 'void () throw(int)'
 
 namespace testCXXConstructorDecl {
   class A { };
   class TestCXXConstructorDecl : public A {
     int I;
     TestCXXConstructorDecl(A &a, int i) : A(a), I(i) { }
     TestCXXConstructorDecl(A &a) : TestCXXConstructorDecl(a, 0) { }
   };
 }
 // CHECK:      CXXConstructorDecl{{.*}} TestCXXConstructorDecl 'void {{.*}}'
 // CHECK-NEXT:   ParmVarDecl{{.*}} a
 // CHECK-NEXT:   ParmVarDecl{{.*}} i
 // CHECK-NEXT:   CXXCtorInitializer{{.*}}A
 // CHECK-NEXT:     Expr
 // CHECK:        CXXCtorInitializer{{.*}}I
 // CHECK-NEXT:     Expr
 // CHECK:        CompoundStmt
 // CHECK:      CXXConstructorDecl{{.*}} TestCXXConstructorDecl 'void {{.*}}'
 // CHECK-NEXT:   ParmVarDecl{{.*}} a
 // CHECK-NEXT:   CXXCtorInitializer{{.*}}TestCXXConstructorDecl
 // CHECK-NEXT:     CXXConstructExpr{{.*}}TestCXXConstructorDecl
 
 class TestCXXDestructorDecl {
   ~TestCXXDestructorDecl() { }
 };
 // CHECK:      CXXDestructorDecl{{.*}} ~TestCXXDestructorDecl 'void () noexcept'
 // CHECK-NEXT:   CompoundStmt
 
 // Test that the range of a defaulted members is computed correctly.
 class TestMemberRanges {
 public:
   TestMemberRanges() = default;
   TestMemberRanges(const TestMemberRanges &Other) = default;
   TestMemberRanges(TestMemberRanges &&Other) = default;
   ~TestMemberRanges() = default;
   TestMemberRanges &operator=(const TestMemberRanges &Other) = default;
   TestMemberRanges &operator=(TestMemberRanges &&Other) = default;
 };
 void SomeFunction() {
   TestMemberRanges A;
   TestMemberRanges B(A);
   B = A;
   A = static_cast<TestMemberRanges &&>(B);
   TestMemberRanges C(static_cast<TestMemberRanges &&>(A));
 }
 // CHECK:      CXXConstructorDecl{{.*}} <line:{{.*}}:3, col:30>
 // CHECK:      CXXConstructorDecl{{.*}} <line:{{.*}}:3, col:59>
 // CHECK:      CXXConstructorDecl{{.*}} <line:{{.*}}:3, col:54>
 // CHECK:      CXXDestructorDecl{{.*}} <line:{{.*}}:3, col:31>
 // CHECK:      CXXMethodDecl{{.*}} <line:{{.*}}:3, col:70>
 // CHECK:      CXXMethodDecl{{.*}} <line:{{.*}}:3, col:65>
 
 class TestCXXConversionDecl {
   operator int() { return 0; }
 };
 // CHECK:      CXXConversionDecl{{.*}} operator int 'int ()'
 // CHECK-NEXT:   CompoundStmt
 
 namespace TestStaticAssertDecl {
   static_assert(true, "msg");
 }
 // CHECK:      NamespaceDecl{{.*}} TestStaticAssertDecl
 // CHECK-NEXT:   StaticAssertDecl{{.*> .*$}}
 // CHECK-NEXT:     CXXBoolLiteralExpr
 // CHECK-NEXT:     StringLiteral
 
 namespace testFunctionTemplateDecl {
   class A { };
   class B { };
   class C { };
   class D { };
   template<typename T> void TestFunctionTemplate(T) { }
 
   // implicit instantiation
   void bar(A a) { TestFunctionTemplate(a); }
 
   // explicit specialization
   template<> void TestFunctionTemplate(B);
 
   // explicit instantiation declaration
   extern template void TestFunctionTemplate(C);
 
   // explicit instantiation definition
   template void TestFunctionTemplate(D);
 }
   // CHECK:       FunctionTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-14]]:3, col:55> col:29 TestFunctionTemplate
   // CHECK-NEXT:  |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 referenced typename depth 0 index 0 T
   // CHECK-NEXT:  |-FunctionDecl 0x{{.+}} <col:24, col:55> col:29 TestFunctionTemplate 'void (T)'
   // CHECK-NEXT:  | |-ParmVarDecl 0x{{.+}} <col:50> col:51 'T'
   // CHECK-NEXT:  | `-CompoundStmt 0x{{.+}} <col:53, col:55>
   // CHECK-NEXT:  |-FunctionDecl 0x{{.+}} <col:24, col:55> col:29 used TestFunctionTemplate 'void (testFunctionTemplateDecl::A)'
   // CHECK-NEXT:  | |-TemplateArgument type 'testFunctionTemplateDecl::A'
   // CHECK-NEXT:  | | `-RecordType 0{{.+}} 'testFunctionTemplateDecl::A'
   // CHECK-NEXT:  | |   `-CXXRecord 0x{{.+}} 'A'
   // CHECK-NEXT:  | |-ParmVarDecl 0x{{.+}} <col:50> col:51 'testFunctionTemplateDecl::A':'testFunctionTemplateDecl::A'
   // CHECK-NEXT:  | `-CompoundStmt 0x{{.+}} <col:53, col:55>
   // CHECK-NEXT:  |-Function 0x{{.+}} 'TestFunctionTemplate' 'void (testFunctionTemplateDecl::B)'
   // CHECK-NEXT:  |-FunctionDecl 0x{{.+}} <col:24, col:55> col:29 TestFunctionTemplate 'void (testFunctionTemplateDecl::C)'
   // CHECK-NEXT:  | |-TemplateArgument type 'testFunctionTemplateDecl::C'
   // CHECK-NEXT:  | | `-RecordType 0{{.+}} 'testFunctionTemplateDecl::C'
   // CHECK-NEXT:  | |   `-CXXRecord 0x{{.+}} 'C'
   // CHECK-NEXT:  | `-ParmVarDecl 0x{{.+}} <col:50> col:51 'testFunctionTemplateDecl::C':'testFunctionTemplateDecl::C'
   // CHECK-NEXT:  `-FunctionDecl 0x{{.+}} <col:24, col:55> col:29 TestFunctionTemplate 'void (testFunctionTemplateDecl::D)'
   // CHECK-NEXT:    |-TemplateArgument type 'testFunctionTemplateDecl::D'
   // CHECK-NEXT:    | `-RecordType 0{{.+}} 'testFunctionTemplateDecl::D'
   // CHECK-NEXT:    |   `-CXXRecord 0x{{.+}} 'D'
   // CHECK-NEXT:    |-ParmVarDecl 0x{{.+}} <col:50> col:51 'testFunctionTemplateDecl::D':'testFunctionTemplateDecl::D'
   // CHECK-NEXT:    `-CompoundStmt 0x{{.+}} <col:53, col:55>
 
   // CHECK:       FunctionDecl 0x{{.+}} prev 0x{{.+}} <{{.+}}:[[@LINE-32]]:3, col:41> col:19 TestFunctionTemplate 'void (testFunctionTemplateDecl::B)'
   // CHECK-NEXT:  |-TemplateArgument type 'testFunctionTemplateDecl::B'
   // CHECK-NEXT:  | `-RecordType 0{{.+}} 'testFunctionTemplateDecl::B'
   // CHECK-NEXT:  |   `-CXXRecord 0x{{.+}} 'B'
   // CHECK-NEXT:  `-ParmVarDecl 0x{{.+}} <col:40> col:41 'testFunctionTemplateDecl::B'
 
 
 namespace testClassTemplateDecl {
   class A { };
   class B { };
   class C { };
   class D { };
 
   template<typename T> class TestClassTemplate {
   public:
     TestClassTemplate();
     ~TestClassTemplate();
     int j();
     int i;
   };
 
   // implicit instantiation
   TestClassTemplate<A> a;
 
   // explicit specialization
   template<> class TestClassTemplate<B> {
     int j;
   };
 
   // explicit instantiation declaration
   extern template class TestClassTemplate<C>;
 
   // explicit instantiation definition
   template class TestClassTemplate<D>;
 
   // partial explicit specialization
   template<typename T1, typename T2> class TestClassTemplatePartial {
     int i;
   };
   template<typename T1> class TestClassTemplatePartial<T1, A> {
     int j;
   };
 
   template<typename T = int> struct TestTemplateDefaultType;
   template<typename T> struct TestTemplateDefaultType { };
 
   template<int I = 42> struct TestTemplateDefaultNonType;
   template<int I> struct TestTemplateDefaultNonType { };
 
   template<template<typename> class TT = TestClassTemplate> struct TestTemplateTemplateDefaultType;
   template<template<typename> class TT> struct TestTemplateTemplateDefaultType { };
 }
 
 // CHECK:       ClassTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-40]]:3, line:[[@LINE-34]]:3> line:[[@LINE-40]]:30 TestClassTemplate
 // CHECK-NEXT:  |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 typename depth 0 index 0 T
 // CHECK-NEXT:  |-CXXRecordDecl 0x{{.+}} <col:24, line:[[@LINE-36]]:3> line:[[@LINE-42]]:30 class TestClassTemplate definition
 // CHECK-NEXT:  | |-DefinitionData standard_layout has_user_declared_ctor can_const_default_init
 // CHECK-NEXT:  | | |-DefaultConstructor exists non_trivial user_provided
 // CHECK-NEXT:  | | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | | |-MoveConstructor
 // CHECK-NEXT:  | | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | | |-MoveAssignment
 // CHECK-NEXT:  | | `-Destructor non_trivial user_declared
 // CHECK-NEXT:  | |-CXXRecordDecl 0x{{.+}} <col:24, col:30> col:30 implicit referenced class TestClassTemplate
 // CHECK-NEXT:  | |-AccessSpecDecl 0x{{.+}} <line:[[@LINE-50]]:3, col:9> col:3 public
 // CHECK-NEXT:  | |-CXXConstructorDecl 0x{{.+}} <line:[[@LINE-50]]:5, col:23> col:5 TestClassTemplate<T> 'void ()'
 // CHECK-NEXT:  | |-CXXDestructorDecl 0x{{.+}} <line:[[@LINE-50]]:5, col:24> col:5 ~TestClassTemplate<T> 'void ()'
 // CHECK-NEXT:  | |-CXXMethodDecl 0x{{.+}} <line:[[@LINE-50]]:5, col:11> col:9 j 'int ()'
 // CHECK-NEXT:  | `-FieldDecl 0x{{.+}} <line:[[@LINE-50]]:5, col:9> col:9 i 'int'
 // CHECK-NEXT:  |-ClassTemplateSpecializationDecl 0x{{.+}} <line:[[@LINE-56]]:3, line:[[@LINE-50]]:3> line:[[@LINE-56]]:30 class TestClassTemplate definition
 // CHECK-NEXT:  | |-DefinitionData standard_layout has_user_declared_ctor can_const_default_init
 // CHECK-NEXT:  | | |-DefaultConstructor exists non_trivial user_provided
 // CHECK-NEXT:  | | |-CopyConstructor simple trivial has_const_param implicit_has_const_param
 // CHECK-NEXT:  | | |-MoveConstructor
 // CHECK-NEXT:  | | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | | |-MoveAssignment
 // CHECK-NEXT:  | | `-Destructor non_trivial user_declared
 // CHECK-NEXT:  | |-TemplateArgument type 'testClassTemplateDecl::A'
 // CHECK-NEXT:  | | `-RecordType 0{{.+}} 'testClassTemplateDecl::A'
 // CHECK-NEXT:  | |   `-CXXRecord 0x{{.+}} 'A'
 // CHECK-NEXT:  | |-CXXRecordDecl 0x{{.+}} prev 0x{{.+}} <col:24, col:30> col:30 implicit class TestClassTemplate
 // CHECK-NEXT:  | |-AccessSpecDecl 0x{{.+}} <line:[[@LINE-67]]:3, col:9> col:3 public
 // CHECK-NEXT:  | |-CXXConstructorDecl 0x{{.+}} <line:[[@LINE-67]]:5, col:23> col:5 used TestClassTemplate 'void ()'
 // CHECK-NEXT:  | |-CXXDestructorDecl 0x{{.+}} <line:[[@LINE-67]]:5, col:24> col:5 used ~TestClassTemplate 'void () noexcept'
 // CHECK-NEXT:  | |-CXXMethodDecl 0x{{.+}} <line:[[@LINE-67]]:5, col:11> col:9 j 'int ()'
 // CHECK-NEXT:  | |-FieldDecl 0x{{.+}} <line:[[@LINE-67]]:5, col:9> col:9 i 'int'
 // CHECK-NEXT:  | `-CXXConstructorDecl 0x{{.+}} <line:[[@LINE-73]]:30> col:30 implicit constexpr TestClassTemplate 'void (const testClassTemplateDecl::TestClassTemplate<testClassTemplateDecl::A> &)' inline default trivial noexcept-unevaluated 0x{{.+}}
 // CHECK-NEXT:  |   `-ParmVarDecl 0x{{.+}} <col:30> col:30 'const testClassTemplateDecl::TestClassTemplate<testClassTemplateDecl::A> &'
 // CHECK-NEXT:  |-ClassTemplateSpecialization 0x{{.+}} 'TestClassTemplate'
 // CHECK-NEXT:  |-ClassTemplateSpecialization 0x{{.+}} 'TestClassTemplate'
 // CHECK-NEXT:  `-ClassTemplateSpecialization 0x{{.+}} 'TestClassTemplate'
 
 // CHECK:       ClassTemplateSpecializationDecl 0x{{.+}} <{{.+}}:[[@LINE-67]]:3, line:[[@LINE-65]]:3> line:[[@LINE-67]]:20 class TestClassTemplate definition
 // CHECK-NEXT:  |-DefinitionData pass_in_registers standard_layout trivially_copyable trivial literal
 // CHECK-NEXT:  | |-DefaultConstructor exists trivial needs_implicit
 // CHECK-NEXT:  | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | |-MoveConstructor exists simple trivial needs_implicit
 // CHECK-NEXT:  | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | |-MoveAssignment exists simple trivial needs_implicit
 // CHECK-NEXT:  | `-Destructor simple irrelevant trivial needs_implicit
 // CHECK-NEXT:  |-TemplateArgument type 'testClassTemplateDecl::B'
 // CHECK-NEXT:  | `-RecordType 0{{.+}} 'testClassTemplateDecl::B'
 // CHECK-NEXT:  |   `-CXXRecord 0x{{.+}} 'B'
 // CHECK-NEXT:  |-CXXRecordDecl 0x{{.+}} <col:14, col:20> col:20 implicit class TestClassTemplate
 // CHECK-NEXT:  `-FieldDecl 0x{{.+}} <line:[[@LINE-78]]:5, col:9> col:9 j 'int'
 
 // CHECK:       ClassTemplateSpecializationDecl 0x{{.+}} <{{.+}}:{{.*}}:3, col:44> col:25 class TestClassTemplate definition
 // CHECK-NEXT:  |-DefinitionData standard_layout has_user_declared_ctor can_const_default_init
 // CHECK-NEXT:  | |-DefaultConstructor exists non_trivial user_provided
 // CHECK-NEXT:  | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | |-MoveConstructor
 // CHECK-NEXT:  | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | |-MoveAssignment
 // CHECK-NEXT:  | `-Destructor non_trivial user_declared
 // CHECK-NEXT:  |-TemplateArgument type 'testClassTemplateDecl::C'
 // CHECK-NEXT:  | `-RecordType 0{{.+}} 'testClassTemplateDecl::C'
 // CHECK-NEXT:  |   `-CXXRecord 0x{{.+}} 'C'
 // CHECK-NEXT:  |-CXXRecordDecl 0x{{.+}} prev 0x{{.+}} <line:[[@LINE-104]]:24, col:30> col:30 implicit class TestClassTemplate
 // CHECK-NEXT:  |-AccessSpecDecl 0x{{.+}} <line:[[@LINE-104]]:3, col:9> col:3 public
 // CHECK-NEXT:  |-CXXConstructorDecl 0x{{.+}} <line:[[@LINE-104]]:5, col:23> col:5 TestClassTemplate 'void ()'
 // CHECK-NEXT:  |-CXXDestructorDecl 0x{{.+}} <line:[[@LINE-104]]:5, col:24> col:5 ~TestClassTemplate 'void ()' noexcept-unevaluated 0x{{.+}}
 // CHECK-NEXT:  |-CXXMethodDecl 0x{{.+}} <line:[[@LINE-104]]:5, col:11> col:9 j 'int ()'
 // CHECK-NEXT:  `-FieldDecl 0x{{.+}} <line:[[@LINE-104]]:5, col:9> col:9 i 'int'
 
 // CHECK:       ClassTemplateSpecializationDecl 0x{{.+}} <{{.+}}:[[@LINE-91]]:3, col:37> col:18 class TestClassTemplate definition
 // CHECK-NEXT:  |-DefinitionData standard_layout has_user_declared_ctor can_const_default_init
 // CHECK-NEXT:  | |-DefaultConstructor exists non_trivial user_provided
 // CHECK-NEXT:  | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | |-MoveConstructor
 // CHECK-NEXT:  | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | |-MoveAssignment
 // CHECK-NEXT:  | `-Destructor non_trivial user_declared
 // CHECK-NEXT:  |-TemplateArgument type 'testClassTemplateDecl::D'
 // CHECK-NEXT:  | `-RecordType 0{{.+}} 'testClassTemplateDecl::D'
 // CHECK-NEXT:  |   `-CXXRecord 0x{{.+}} 'D'
 // CHECK-NEXT:  |-CXXRecordDecl 0x{{.+}} prev 0x{{.+}} <line:[[@LINE-122]]:24, col:30> col:30 implicit class TestClassTemplate
 // CHECK-NEXT:  |-AccessSpecDecl 0x{{.+}} <line:[[@LINE-122]]:3, col:9> col:3 public
 // CHECK-NEXT:  |-CXXConstructorDecl 0x{{.+}} <line:[[@LINE-122]]:5, col:23> col:5 TestClassTemplate 'void ()'
 // CHECK-NEXT:  |-CXXDestructorDecl 0x{{.+}} <line:[[@LINE-122]]:5, col:24> col:5 ~TestClassTemplate 'void ()' noexcept-unevaluated 0x{{.+}}
 // CHECK-NEXT:  |-CXXMethodDecl 0x{{.+}} <line:[[@LINE-122]]:5, col:11> col:9 j 'int ()'
 // CHECK-NEXT:  `-FieldDecl 0x{{.+}} <line:[[@LINE-122]]:5, col:9> col:9 i 'int'
 
 // CHECK:      ClassTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-106]]:3, line:[[@LINE-104]]:3> line:[[@LINE-106]]:44 TestClassTemplatePartial
 // CHECK-NEXT:  |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 typename depth 0 index 0 T1
 // CHECK-NEXT:  |-TemplateTypeParmDecl 0x{{.+}} <col:25, col:34> col:34 typename depth 0 index 1 T2
 // CHECK-NEXT:  `-CXXRecordDecl 0x{{.+}} <col:38, line:[[@LINE-107]]:3> line:[[@LINE-109]]:44 class TestClassTemplatePartial definition
 // CHECK-NEXT:    |-DefinitionData standard_layout trivially_copyable trivial literal
 // CHECK-NEXT:    | |-DefaultConstructor exists trivial needs_implicit
 // CHECK-NEXT:    | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | |-MoveConstructor exists simple trivial needs_implicit
 // CHECK-NEXT:    | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | |-MoveAssignment exists simple trivial needs_implicit
 // CHECK-NEXT:    | `-Destructor simple irrelevant trivial needs_implicit
 // CHECK-NEXT:    |-CXXRecordDecl 0x{{.+}} <col:38, col:44> col:44 implicit class TestClassTemplatePartial
 // CHECK-NEXT:    `-FieldDecl 0x{{.+}} <line:[[@LINE-117]]:5, col:9> col:9 i 'int'
 
 // CHECK:       ClassTemplatePartialSpecializationDecl 0x{{.+}} <{{.+}}:[[@LINE-117]]:3, line:[[@LINE-115]]:3> line:[[@LINE-117]]:31 class TestClassTemplatePartial definition
 // CHECK-NEXT:  |-DefinitionData standard_layout trivially_copyable trivial literal
 // CHECK-NEXT:  | |-DefaultConstructor exists trivial needs_implicit
 // CHECK-NEXT:  | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | |-MoveConstructor exists simple trivial needs_implicit
 // CHECK-NEXT:  | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:  | |-MoveAssignment exists simple trivial needs_implicit
 // CHECK-NEXT:  | `-Destructor simple irrelevant trivial needs_implicit
 // CHECK-NEXT:  |-TemplateArgument type 'type-parameter-0-0'
 // CHECK-NEXT:  | `-TemplateTypeParmType 0x{{.+}} 'type-parameter-0-0' dependent depth 0 index 0
 // CHECK-NEXT:  |-TemplateArgument type 'testClassTemplateDecl::A'
 // CHECK-NEXT:  | `-RecordType 0x{{.+}} 'testClassTemplateDecl::A'
 // CHECK-NEXT:  |   `-CXXRecord 0x{{.+}} 'A'
 // CHECK-NEXT:  |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 referenced typename depth 0 index 0 T1
 // CHECK-NEXT:  |-CXXRecordDecl 0x{{.+}} <col:25, col:31> col:31 implicit class TestClassTemplatePartial
 // CHECK-NEXT:  `-FieldDecl 0x{{.+}} <line:[[@LINE-131]]:5, col:9> col:9 j 'int'
 
 // CHECK:       ClassTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-130]]:3, col:37> col:37 TestTemplateDefaultType
 // CHECK-NEXT:  |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:25> col:21 typename depth 0 index 0 T
 // CHECK-NEXT:  | `-TemplateArgument type 'int'
 // CHECK-NEXT:  |   `-BuiltinType 0x{{.+}} 'int'
 // CHECK-NEXT:  `-CXXRecordDecl 0x{{.+}} <col:30, col:37> col:37 struct TestTemplateDefaultType
 
 // CHECK:       ClassTemplateDecl 0x{{.+}} prev 0x{{.+}} <{{.+}}:[[@LINE-135]]:3, col:57> col:31 TestTemplateDefaultType
 // CHECK-NEXT:  |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 typename depth 0 index 0 T
 // CHECK-NEXT:  | `-TemplateArgument type 'int'
 // CHECK-NEXT:  |   |-inherited from TemplateTypeParm 0x{{.+}} 'T'
 // CHECK-NEXT:  |   `-BuiltinType 0x{{.+}} 'int'
 // CHECK-NEXT:  `-CXXRecordDecl 0x{{.+}} prev 0x{{.+}} <col:24, col:57> col:31 struct TestTemplateDefaultType definition
 // CHECK-NEXT:    |-DefinitionData empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
 // CHECK-NEXT:    | |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
 // CHECK-NEXT:    | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | |-MoveConstructor exists simple trivial needs_implicit
 // CHECK-NEXT:    | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | |-MoveAssignment exists simple trivial needs_implicit
 // CHECK-NEXT:    | `-Destructor simple irrelevant trivial needs_implicit
 // CHECK-NEXT:    `-CXXRecordDecl 0x{{.+}} <col:24, col:31> col:31 implicit struct TestTemplateDefaultType
 
 // CHECK:       ClassTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-148]]:3, col:31> col:31 TestTemplateDefaultNonType
 // CHECK-NEXT:  |-NonTypeTemplateParmDecl 0x{{.+}} <col:12, col:20> col:16 'int' depth 0 index 0 I
 // CHECK-NEXT:  | `-TemplateArgument expr
 // CHECK-NEXT:  |   `-ConstantExpr 0x{{.+}} <col:20> 'int'
 // CHECK-NEXT:  |     |-value: Int 42
 // CHECK-NEXT:  |     `-IntegerLiteral 0x{{.+}} <col:20> 'int' 42
 // CHECK-NEXT:  `-CXXRecordDecl 0x{{.+}} <col:24, col:31> col:31 struct TestTemplateDefaultNonType
 
 // CHECK:       ClassTemplateDecl 0x{{.+}} <{{.+}}:{{.*}}:3, col:68> col:68 TestTemplateTemplateDefaultType
 // CHECK-NEXT:  |-TemplateTemplateParmDecl 0x{{.+}} <col:12, col:42> col:37 depth 0 index 0 TT
 // CHECK-NEXT:  | |-TemplateTypeParmDecl 0x{{.+}} <col:21> col:29 typename depth 1 index 0
 // CHECK-NEXT:  | `-TemplateArgument <col:42> template TestClassTemplate
 // CHECK-NEXT:  `-CXXRecordDecl 0x{{.+}} <col:61, col:68> col:68 struct TestTemplateTemplateDefaultType
 
 // CHECK:       ClassTemplateDecl 0x{{.+}} prev 0x{{.+}} <{{.+}}:{{.*}}:3, col:82> col:48 TestTemplateTemplateDefaultType
 // CHECK-NEXT:  |-TemplateTemplateParmDecl 0x{{.+}} <col:12, col:37> col:37 depth 0 index 0 TT
 // CHECK-NEXT:  | |-TemplateTypeParmDecl 0x{{.+}} <col:21> col:29 typename depth 1 index 0
 // CHECK-NEXT:  | `-TemplateArgument <line:{{.*}}:42> template TestClassTemplate
 // CHECK-NEXT:  |   `-inherited from TemplateTemplateParm 0x{{.+}} 'TT'
 // CHECK-NEXT:  `-CXXRecordDecl 0x{{.+}} prev 0x{{.+}} <line:{{.*}}:41, col:82> col:48 struct TestTemplateTemplateDefaultType definition
 // CHECK-NEXT:    |-DefinitionData empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
 // CHECK-NEXT:    | |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
 // CHECK-NEXT:    | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | |-MoveConstructor exists simple trivial needs_implicit
 // CHECK-NEXT:    | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | |-MoveAssignment exists simple trivial needs_implicit
 // CHECK-NEXT:    | `-Destructor simple irrelevant trivial needs_implicit
 // CHECK-NEXT:    `-CXXRecordDecl 0x{{.+}} <col:41, col:48> col:48 implicit struct TestTemplateTemplateDefaultType
 
 
 // PR15220 dump instantiation only once
 namespace testCanonicalTemplate {
   class A {};
 
   template<typename T> void TestFunctionTemplate(T);
   template<typename T> void TestFunctionTemplate(T);
   void bar(A a) { TestFunctionTemplate(a); }
   // CHECK:      FunctionTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-3]]:3, col:51> col:29 TestFunctionTemplate
   // CHECK-NEXT:   |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 referenced typename depth 0 index 0 T
   // CHECK-NEXT:   |-FunctionDecl 0x{{.*}} <col:24, col:51> col:29 TestFunctionTemplate 'void (T)'
   // CHECK-NEXT:   | `-ParmVarDecl 0x{{.*}} <col:50> col:51 'T'
   // CHECK-NEXT:   `-FunctionDecl 0x{{.*}} <line:[[@LINE-6]]:24, col:51> col:29 used TestFunctionTemplate 'void (testCanonicalTemplate::A)'
   // CHECK-NEXT:     |-TemplateArgument type 'testCanonicalTemplate::A'
   // CHECK-NEXT:     | `-RecordType 0x{{.+}} 'testCanonicalTemplate::A'
   // CHECK-NEXT:     |   `-CXXRecord 0x{{.+}} 'A'
   // CHECK-NEXT:     `-ParmVarDecl 0x{{.*}} <col:50> col:51 'testCanonicalTemplate::A':'testCanonicalTemplate::A'
 
   // CHECK:      FunctionTemplateDecl 0x{{.+}} prev 0x{{.+}} <{{.+}}:[[@LINE-12]]:3, col:51> col:29 TestFunctionTemplate
   // CHECK-NEXT:   |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 referenced typename depth 0 index 0 T
   // CHECK-NEXT:   |-FunctionDecl{{.*}} 0x{{.+}} prev 0x{{.+}} <col:24, col:51> col:29 TestFunctionTemplate 'void (T)'
   // CHECK-NEXT:   | `-ParmVarDecl 0x{{.+}} <col:50> col:51 'T'
   // CHECK-NEXT:   `-Function 0x{{.+}} 'TestFunctionTemplate' 'void (testCanonicalTemplate::A)'
   // CHECK-NOT:      TemplateArgument
 
   template<typename T1> class TestClassTemplate {
     template<typename T2> friend class TestClassTemplate;
   };
   TestClassTemplate<A> a;
   // CHECK:      ClassTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-4]]:3, line:[[@LINE-2]]:3> line:[[@LINE-4]]:31 TestClassTemplate
   // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 typename depth 0 index 0 T1
   // CHECK-NEXT: |-CXXRecordDecl 0x{{.+}} <col:25, line:[[@LINE-4]]:3> line:[[@LINE-6]]:31 class TestClassTemplate definition
   // CHECK-NEXT: | |-DefinitionData empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
   // CHECK-NEXT: | | |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
   // CHECK-NEXT: | | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
   // CHECK-NEXT: | | |-MoveConstructor exists simple trivial needs_implicit
   // CHECK-NEXT: | | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
   // CHECK-NEXT: | | |-MoveAssignment exists simple trivial needs_implicit
   // CHECK-NEXT: | | `-Destructor simple irrelevant trivial needs_implicit
   // CHECK-NEXT: | |-CXXRecordDecl 0x{{.+}} <col:25, col:31> col:31 implicit class TestClassTemplate
   // CHECK-NEXT: | `-FriendDecl 0x{{.+}} <line:[[@LINE-14]]:5, col:40> col:40
   // CHECK-NEXT: |   `-ClassTemplateDecl 0x{{.+}} parent 0x{{.+}} <col:5, col:40> col:40 TestClassTemplate
   // CHECK-NEXT: |     |-TemplateTypeParmDecl 0x{{.+}} <col:14, col:23> col:23 typename depth 1 index 0 T2
   // CHECK-NEXT: |     `-CXXRecordDecl 0x{{.+}} parent 0x{{.+}} <col:34, col:40> col:40 class TestClassTemplate
   // CHECK-NEXT: `-ClassTemplateSpecializationDecl 0x{{.+}} <line:[[@LINE-19]]:3, line:[[@LINE-17]]:3> line:[[@LINE-19]]:31 class TestClassTemplate definition
   // CHECK-NEXT:   |-DefinitionData pass_in_registers empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
   // CHECK-NEXT:   | |-DefaultConstructor exists trivial constexpr defaulted_is_constexpr
   // CHECK-NEXT:   | |-CopyConstructor simple trivial has_const_param implicit_has_const_param
   // CHECK-NEXT:   | |-MoveConstructor exists simple trivial
   // CHECK-NEXT:   | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
   // CHECK-NEXT:   | |-MoveAssignment exists simple trivial needs_implicit
   // CHECK-NEXT:   | `-Destructor simple irrelevant trivial needs_implicit
   // CHECK-NEXT:   |-TemplateArgument type 'testCanonicalTemplate::A'
   // CHECK-NEXT:   | `-RecordType 0x{{.+}} 'testCanonicalTemplate::A'
   // CHECK-NEXT:   |   `-CXXRecord 0x{{.+}} 'A'
   // CHECK-NEXT:   |-CXXRecordDecl 0x{{.+}} prev 0x{{.+}} <col:25, col:31> col:31 implicit class TestClassTemplate
   // CHECK-NEXT:   |-FriendDecl 0x{{.+}} <line:[[@LINE-30]]:5, col:40> col:40
   // CHECK-NEXT:   | `-ClassTemplateDecl 0x{{.+}} parent 0x{{.+}} prev 0x{{.+}} <col:5, col:40> col:40 TestClassTemplate
   // CHECK-NEXT:   |   |-TemplateTypeParmDecl 0x{{.+}} <col:14, col:23> col:23 typename depth 0 index 0 T2
   // CHECK-NEXT:   |   |-CXXRecordDecl 0x{{.+}} parent 0x{{.+}} prev 0x{{.+}} <col:34, col:40> col:40 class TestClassTemplate
   // CHECK-NEXT:   |   `-ClassTemplateSpecialization 0x{{.+}} 'TestClassTemplate'
   // CHECK-NEXT:   |-CXXConstructorDecl 0x{{.+}} <line:[[@LINE-36]]:31> col:31 implicit used constexpr TestClassTemplate 'void () noexcept' inline default trivial
   // CHECK-NEXT:   | `-CompoundStmt 0x{{.+}} <col:31>
   // CHECK-NEXT:   |-CXXConstructorDecl 0x{{.+}} <col:31> col:31 implicit constexpr TestClassTemplate 'void (const testCanonicalTemplate::TestClassTemplate<testCanonicalTemplate::A> &)' inline default trivial noexcept-unevaluated 0x{{.+}}
   // CHECK-NEXT:   | `-ParmVarDecl 0x{{.+}} <col:31> col:31 'const testCanonicalTemplate::TestClassTemplate<testCanonicalTemplate::A> &'
   // CHECK-NEXT:   `-CXXConstructorDecl 0x{{.+}} <col:31> col:31 implicit constexpr TestClassTemplate 'void (testCanonicalTemplate::TestClassTemplate<testCanonicalTemplate::A> &&)' inline default trivial noexcept-unevaluated 0x{{.+}}
   // CHECK-NEXT:     `-ParmVarDecl 0x{{.+}} <col:31> col:31 'testCanonicalTemplate::TestClassTemplate<testCanonicalTemplate::A> &&'
 
 
   template<typename T1> class TestClassTemplate2;
   template<typename T1> class TestClassTemplate2;
   template<typename T1> class TestClassTemplate2 {
   };
   TestClassTemplate2<A> a2;
   // CHECK:      ClassTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-5]]:3, col:31> col:31 TestClassTemplate2
   // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 typename depth 0 index 0 T1
   // CHECK-NEXT: |-CXXRecordDecl 0x{{.+}} <col:25, col:31> col:31 class TestClassTemplate2
   // CHECK-NEXT: `-ClassTemplateSpecializationDecl 0x{{.+}} <line:[[@LINE-6]]:3, line:[[@LINE-5]]:3> line:[[@LINE-6]]:31 class TestClassTemplate2 definition
   // CHECK-NEXT:   |-DefinitionData pass_in_registers empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
   // CHECK-NEXT:   | |-DefaultConstructor exists trivial constexpr defaulted_is_constexpr
   // CHECK-NEXT:   | |-CopyConstructor simple trivial has_const_param implicit_has_const_param
   // CHECK-NEXT:   | |-MoveConstructor exists simple trivial
   // CHECK-NEXT:   | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
   // CHECK-NEXT:   | |-MoveAssignment exists simple trivial needs_implicit
   // CHECK-NEXT:   | `-Destructor simple irrelevant trivial needs_implicit
   // CHECK-NEXT:   |-TemplateArgument type 'testCanonicalTemplate::A'
   // CHECK-NEXT:   | `-RecordType 0x{{.+}} 'testCanonicalTemplate::A'
   // CHECK-NEXT:   |   `-CXXRecord 0x{{.+}} 'A'
   // CHECK-NEXT:   |-CXXRecordDecl 0x{{.+}} prev 0x{{.+}} <col:25, col:31> col:31 implicit class TestClassTemplate2
   // CHECK-NEXT:   |-CXXConstructorDecl 0x{{.+}} <col:31> col:31 implicit used constexpr TestClassTemplate2 'void () noexcept' inline default trivial
   // CHECK-NEXT:   | `-CompoundStmt 0x{{.+}} <col:31>
   // CHECK-NEXT:   |-CXXConstructorDecl 0x{{.+}} <col:31> col:31 implicit constexpr TestClassTemplate2 'void (const testCanonicalTemplate::TestClassTemplate2<testCanonicalTemplate::A> &)' inline default trivial noexcept-unevaluated 0x{{.+}}
   // CHECK-NEXT:   | `-ParmVarDecl 0x{{.+}} <col:31> col:31 'const testCanonicalTemplate::TestClassTemplate2<testCanonicalTemplate::A> &'
   // CHECK-NEXT:   `-CXXConstructorDecl 0x{{.+}} <col:31> col:31 implicit constexpr TestClassTemplate2 'void (testCanonicalTemplate::TestClassTemplate2<testCanonicalTemplate::A> &&)' inline default trivial noexcept-unevaluated 0x{{.+}}
   // CHECK-NEXT:     `-ParmVarDecl 0x{{.+}} <col:31> col:31 'testCanonicalTemplate::TestClassTemplate2<testCanonicalTemplate::A> &&'
 
   // CHECK:      ClassTemplateDecl 0x{{.+}} prev 0x{{.+}} <{{.+}}:[[@LINE-26]]:3, col:31> col:31 TestClassTemplate2
   // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 typename depth 0 index 0 T1
   // CHECK-NEXT: |-CXXRecordDecl 0x{{.+}} prev 0x{{.+}} <col:25, col:31> col:31 class TestClassTemplate2
   // CHECK-NEXT: `-ClassTemplateSpecialization 0x{{.+}} 'TestClassTemplate2'
 
   // CHECK:      ClassTemplateDecl 0x{{.+}} prev 0x{{.+}} <{{.+}}:[[@LINE-30]]:3, line:[[@LINE-29]]:3> line:[[@LINE-30]]:31 TestClassTemplate2
   // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 typename depth 0 index 0 T1
   // CHECK-NEXT: |-CXXRecordDecl 0x{{.+}} prev 0x{{.+}} <col:25, line:[[@LINE-31]]:3> line:[[@LINE-32]]:31 class TestClassTemplate2 definition
   // CHECK-NEXT: | |-DefinitionData empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
   // CHECK-NEXT: | | |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
   // CHECK-NEXT: | | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
   // CHECK-NEXT: | | |-MoveConstructor exists simple trivial needs_implicit
   // CHECK-NEXT: | | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
   // CHECK-NEXT: | | |-MoveAssignment exists simple trivial needs_implicit
   // CHECK-NEXT: | | `-Destructor simple irrelevant trivial needs_implicit
   // CHECK-NEXT: | `-CXXRecordDecl 0x{{.+}} <col:25, col:31> col:31 implicit class TestClassTemplate2
   // CHECK-NEXT: `-ClassTemplateSpecialization 0x{{.+}} 'TestClassTemplate2'
 
   struct S {
       template<typename T> static const T TestVarTemplate; // declaration of a static data member template
   };
   template<typename T>
   const T S::TestVarTemplate = { }; // definition of a static data member template
 
   void f()
   {
     int i = S::TestVarTemplate<int>;
     int j = S::TestVarTemplate<int>;
   }
 
   // CHECK:      VarTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-11]]:7, col:43> col:43 TestVarTemplate
   // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <col:16, col:25> col:25 referenced typename depth 0 index 0 T
   // CHECK-NEXT: |-VarDecl 0x{{.+}} <col:28, col:43> col:43 TestVarTemplate 'const T' static
   // CHECK-NEXT: |-VarTemplateSpecializationDecl 0x{{.+}} parent 0x{{.+}} prev 0x{{.+}} <line:[[@LINE-11]]:3, col:34> col:14 referenced TestVarTemplate 'const int':'const int' cinit
   // CHECK-NEXT: | |-TemplateArgument type 'int'
   // CHECK-NEXT: | | `-BuiltinType 0x{{.+}} 'int'
   // CHECK-NEXT: | `-InitListExpr 0x{{.+}} <col:32, col:34> 'int':'int'
   // CHECK-NEXT: `-VarTemplateSpecializationDecl 0x{{.+}} <line:[[@LINE-18]]:28, col:43> col:43 referenced TestVarTemplate 'const int':'const int' static
   // CHECK-NEXT:   `-TemplateArgument type 'int'
 
   // CHECK:     VarTemplateSpecializationDecl 0x{{.+}} <{{.+}}:[[@LINE-21]]:28, col:43> col:43 referenced TestVarTemplate 'const int':'const int' static
   // CHECK-NEXT:`-TemplateArgument type 'int'
   // CHECK-NEXT:  `-BuiltinType 0x{{.+}} 'int'
 
   // CHECK:      VarTemplateDecl 0x{{.+}} parent 0x{{.+}} prev 0x{{.+}} <{{.+}}:[[@LINE-23]]:3, line:[[@LINE-22]]:34> col:14 TestVarTemplate
   // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <line:[[@LINE-24]]:12, col:21> col:21 referenced typename depth 0 index 0 T
   // CHECK-NEXT: |-VarDecl 0x{{.+}} parent 0x{{.+}} prev 0x{{.+}} <line:[[@LINE-24]]:3, col:34> col:14 TestVarTemplate 'const T' cinit
   // CHECK-NEXT: | `-InitListExpr 0x{{.+}} <col:32, col:34> 'void'
   // CHECK-NEXT: |-VarTemplateSpecialization 0x{{.+}} 'TestVarTemplate' 'const int':'const int'
   // CHECK-NEXT: `-VarTemplateSpecialization 0x{{.+}} 'TestVarTemplate' 'const int':'const int'
     
   // CHECK:      VarTemplateSpecializationDecl 0x{{.+}} parent 0x{{.+}} prev 0x{{.+}} <{{.+}}:[[@LINE-29]]:3, col:34> col:14 referenced TestVarTemplate 'const int':'const int' cinit
   // CHECK-NEXT: |-TemplateArgument type 'int'
   // CHECK-NEXT: | `-BuiltinType 0x{{.+}} 'int'
   // CHECK-NEXT: `-InitListExpr 0x{{.+}} <col:32, col:34> 'int':'int'
 } 
 
 template <class T>
 class TestClassScopeFunctionSpecialization {
   template<class U> void foo(U a) { }
   template<> void foo<int>(int a) { }
 };
 // CHECK:      ClassScopeFunctionSpecializationDecl
 // CHECK-NEXT:   CXXMethod{{.*}} foo 'void (int)'
 // CHECK-NEXT:     ParmVarDecl
 // CHECK-NEXT:     CompoundStmt
 // CHECK-NEXT:   TemplateArgument{{.*}} 'int'
 
 namespace TestTemplateTypeParmDecl {
   template<typename ... T, class U = int> void foo();
 }
 // CHECK:      NamespaceDecl{{.*}} TestTemplateTypeParmDecl
 // CHECK-NEXT:   FunctionTemplateDecl
 // CHECK-NEXT:     TemplateTypeParmDecl{{.*}} typename depth 0 index 0 ... T
 // CHECK-NEXT:     TemplateTypeParmDecl{{.*}} class depth 0 index 1 U
 // CHECK-NEXT:       TemplateArgument type 'int'
 
 namespace TestNonTypeTemplateParmDecl {
   template<int I = 1, int ... J> void foo();
 }
 // CHECK:      NamespaceDecl{{.*}} TestNonTypeTemplateParmDecl
 // CHECK-NEXT:   FunctionTemplateDecl
 // CHECK-NEXT:     NonTypeTemplateParmDecl{{.*}} 'int' depth 0 index 0 I
 // CHECK-NEXT:       TemplateArgument expr
 // CHECK-NEXT:         ConstantExpr{{.*}} 'int'
 // CHECK-NEXT:           value: Int 1
 // CHECK-NEXT:           IntegerLiteral{{.*}} 'int' 1
 // CHECK-NEXT:     NonTypeTemplateParmDecl{{.*}} 'int' depth 0 index 1 ... J
 
 namespace TestTemplateTemplateParmDecl {
   template<typename T> class A;
   template <template <typename> class T = A, template <typename> class ... U> void foo();
 }
 // CHECK:      NamespaceDecl{{.*}} TestTemplateTemplateParmDecl
 // CHECK:        FunctionTemplateDecl
 // CHECK-NEXT:     TemplateTemplateParmDecl{{.*}} T
 // CHECK-NEXT:       TemplateTypeParmDecl{{.*}} typename
 // CHECK-NEXT:       TemplateArgument{{.*}} template A
 // CHECK-NEXT:     TemplateTemplateParmDecl{{.*}} ... U
 // CHECK-NEXT:       TemplateTypeParmDecl{{.*}} typename
 
 namespace TestTemplateArgument {
   template<typename> class A { };
   template<template<typename> class ...> class B { };
   int foo();
 
   template<typename> class testType { };
   template class testType<int>;
   // CHECK:      ClassTemplateSpecializationDecl{{.*}} class testType
   // CHECK:        TemplateArgument{{.*}} type 'int'
 
   template<int fp(void)> class testDecl { };
   template class testDecl<foo>;
   // CHECK:      ClassTemplateSpecializationDecl{{.*}} class testDecl
   // CHECK:        TemplateArgument{{.*}} decl
   // CHECK-NEXT:     Function{{.*}}foo
 
   template class testDecl<nullptr>;
   // CHECK:      ClassTemplateSpecializationDecl{{.*}} class testDecl
   // CHECK:        TemplateArgument{{.*}} nullptr
 
   template<int> class testIntegral { };
   template class testIntegral<1>;
   // CHECK:      ClassTemplateSpecializationDecl{{.*}} class testIntegral
   // CHECK:        TemplateArgument{{.*}} integral 1
 
   template<template<typename> class> class testTemplate { };
   template class testTemplate<A>;
   // CHECK:      ClassTemplateSpecializationDecl{{.*}} class testTemplate
   // CHECK:        TemplateArgument{{.*}} A
 
   template<template<typename> class ...T> class C {
     B<T...> testTemplateExpansion;
   };
   // FIXME: Need TemplateSpecializationType dumping to test TemplateExpansion.
 
   template<int, int = 0> class testExpr;
   template<int I> class testExpr<I> { };
   // CHECK:      ClassTemplatePartialSpecializationDecl{{.*}} class testExpr
   // CHECK:        TemplateArgument{{.*}} expr
   // CHECK-NEXT:     DeclRefExpr{{.*}}I
 
   template<int, int ...> class testPack { };
   template class testPack<0, 1, 2>;
   // CHECK:      ClassTemplateSpecializationDecl{{.*}} class testPack
   // CHECK:        TemplateArgument{{.*}} integral 0
   // CHECK-NEXT:   TemplateArgument{{.*}} pack
   // CHECK-NEXT:     TemplateArgument{{.*}} integral 1
   // CHECK-NEXT:     TemplateArgument{{.*}} integral 2
 }
 
 namespace testUsingDecl {
   int i;
 }
 namespace TestUsingDecl {
   using testUsingDecl::i;
 }
 // CHECK:      NamespaceDecl{{.*}} TestUsingDecl
 // CHECK-NEXT:   UsingDecl{{.*}} testUsingDecl::i
 // CHECK-NEXT:   UsingShadowDecl{{.*}} Var{{.*}} 'i' 'int'
 
 namespace testUnresolvedUsing {
   class A { };
   template<class T> class B {
   public:
     A a;
   };
   template<class T> class TestUnresolvedUsing : public B<T> {
     using typename B<T>::a;
     using B<T>::a;
   };
 }
 // CHECK: CXXRecordDecl{{.*}} TestUnresolvedUsing
 // CHECK:   UnresolvedUsingTypenameDecl{{.*}} B<T>::a
 // CHECK:   UnresolvedUsingValueDecl{{.*}} B<T>::a
 
 namespace TestLinkageSpecDecl {
   extern "C" void test1();
   extern "C++" void test2();
 }
 // CHECK:      NamespaceDecl{{.*}} TestLinkageSpecDecl
 // CHECK-NEXT:   LinkageSpecDecl{{.*}} C
 // CHECK-NEXT:     FunctionDecl
 // CHECK-NEXT:   LinkageSpecDecl{{.*}} C++
 // CHECK-NEXT:     FunctionDecl
 
 class TestAccessSpecDecl {
 public:
 private:
 protected:
 };
 // CHECK:      CXXRecordDecl{{.*}} class TestAccessSpecDecl
 // CHECK:         CXXRecordDecl{{.*}} class TestAccessSpecDecl
 // CHECK-NEXT:    AccessSpecDecl{{.*}} public
 // CHECK-NEXT:    AccessSpecDecl{{.*}} private
 // CHECK-NEXT:    AccessSpecDecl{{.*}} protected
 
 template<typename T> class TestFriendDecl {
   friend int foo();
   friend class A;
   friend T;
 };
 // CHECK:      CXXRecord{{.*}} TestFriendDecl
 // CHECK:        CXXRecord{{.*}} TestFriendDecl
 // CHECK-NEXT:   FriendDecl
 // CHECK-NEXT:     FunctionDecl{{.*}} foo
 // CHECK-NEXT:   FriendDecl{{.*}} 'class A':'A'
 // CHECK-NEXT:   FriendDecl{{.*}} 'T'
 
 namespace TestFileScopeAsmDecl {
   asm("ret");
 }
 // CHECK:      NamespaceDecl{{.*}} TestFileScopeAsmDecl{{$}}
 // CHECK:        FileScopeAsmDecl{{.*> .*$}}
 // CHECK-NEXT:     StringLiteral
 
 namespace TestFriendDecl2 {
   void f();
   struct S {
     friend void f();
   };
 }
 // CHECK: NamespaceDecl [[TestFriendDecl2:0x.*]] <{{.*}}> {{.*}} TestFriendDecl2
 // CHECK: |-FunctionDecl [[TestFriendDecl2_f:0x.*]] <{{.*}}> {{.*}} f 'void ()'
 // CHECK: `-CXXRecordDecl {{.*}} struct S
 // CHECK:   |-CXXRecordDecl {{.*}} struct S
 // CHECK:   `-FriendDecl
 // CHECK:     `-FunctionDecl {{.*}} parent [[TestFriendDecl2]] prev [[TestFriendDecl2_f]] <{{.*}}> {{.*}} f 'void ()'
 
 namespace Comment {
   extern int Test;
   /// Something here.
   extern int Test;
   extern int Test;
 }
 
 // CHECK: VarDecl {{.*}} Test 'int' extern
 // CHECK-NOT: FullComment
 // CHECK: VarDecl {{.*}} Test 'int' extern
 // CHECK: `-FullComment
 // CHECK:   `-ParagraphComment
 // CHECK:       `-TextComment
 // CHECK: VarDecl {{.*}} Test 'int' extern
 // CHECK-NOT: FullComment

clang/test/AST/ast-dump-namespace-json.cpp

 // CHECK-NEXT:   "end": {
 // CHECK-NEXT:    "offset": 188,
 // CHECK-NEXT:    "line": 15,
 // CHECK-NEXT:    "col": 1,
 // CHECK-NEXT:    "tokLen": 1
 // CHECK-NEXT:   }
 // CHECK-NEXT:  },
 // CHECK-NEXT:  "name": "baz",
+// CHECK-NEXT:  "isNested": true,
 // CHECK-NEXT:  "inner": [
 // CHECK-NEXT:   {
 // CHECK-NEXT:    "id": "0x{{.*}}",
 // CHECK-NEXT:    "kind": "NamespaceDecl",
 // CHECK-NEXT:    "loc": {
 // CHECK-NEXT:     "offset": 181,
 // CHECK-NEXT:     "line": 14,
 // CHECK-NEXT:     "col": 16,

 // CHECK-NEXT:   "end": {
 // CHECK-NEXT:    "offset": 224,
 // CHECK-NEXT:    "line": 18,
 // CHECK-NEXT:    "col": 1,
 // CHECK-NEXT:    "tokLen": 1
 // CHECK-NEXT:   }
 // CHECK-NEXT:  },
 // CHECK-NEXT:  "name": "quux",
+// CHECK-NEXT:  "isNested": true,
 // CHECK-NEXT:  "inner": [
 // CHECK-NEXT:   {
 // CHECK-NEXT:    "id": "0x{{.*}}",
 // CHECK-NEXT:    "kind": "NamespaceDecl",
 // CHECK-NEXT:    "loc": {
 // CHECK-NEXT:     "offset": 214,
 // CHECK-NEXT:     "line": 17,
 // CHECK-NEXT:     "col": 24,

clang/unittests/Sema/ExternalSemaSourceTest.cpp

if (CurrentSema && Typo.getName().getAsString() == CorrectFrom) {
       if (SS)
         DestContext = CurrentSema->computeDeclContext(*SS, EnteringContext);
       if (!DestContext)
         DestContext = Context.getTranslationUnitDecl();
       IdentifierInfo *ToIdent =
           CurrentSema->getPreprocessor().getIdentifierInfo(CorrectTo);
       NamespaceDecl *NewNamespace =
           NamespaceDecl::Create(Context, DestContext, false, Typo.getBeginLoc(),
-                                Typo.getLoc(), ToIdent, nullptr);
+                                Typo.getLoc(), ToIdent, nullptr, false);
       DestContext->addDecl(NewNamespace);
       TypoCorrection Correction(ToIdent);
       Correction.addCorrectionDecl(NewNamespace);
       return Correction;
     }
     return TypoCorrection();
   }