[clang] Prevent that Decl::dump on a CXXRecordDecl deserialises further declarations.

[teemperor]

Summary

Decl::dump is primarily used for debugging to visualise the current state of a declaration. Usually
Decl::dump just displays the current state of the Decl and doesn't actually change any of its
state, however since commit 457226e02a6e8533eaaa864a3fd7c8eeccd2bf58 the method
actually started loading additional declarations from the ExternalASTSource. This causes that
calling Decl::dump during a debugging session now actually does permanent changes to the
AST and will cause the debugged program run to deviate from the original run.

The change that caused this behaviour is the addition of hasConstexprDestructor
(which is called from the TextNodeDumper) which performs a lookup into the current
CXXRecordDecl to find the destructor. All other similar methods just return their
respective bit in the DefinitionData (which obviously doesn't have such side effects).

This just changes the node printer to emit "unknown_constexpr" in case a CXXRecordDecl
is dumped that could potentially call into the ExternalASTSource instead of the
usually empty string/"constexpr". For CXXRecordDecls that can safely be dumped the
old behaviour is preserved

[bruno]

Neat unit test! LGTM (one minor suggestion below).

clang/lib/AST/TextNodeDumper.cpp

1979

How about maybe_constexpr?

[teemperor]

• rename to maybe_constexpr
• Update some dump output tests

[riccibruno]

And what if deserialization is forced?

[teemperor]

In D80878#2258942, @riccibruno wrote:

And what if deserialization is forced?

That's a good point. That should indeed continue to work with the ASTDumper and now (potentially) doesn't. I'll revert.

[teemperor]

• Respect forced deserialisation.

[aprantl]

@teemperor is there a reason why the fixed patch never landed? This looks a good improvement to have.

[teemperor]

This is technically in the "Waiting on Review" queue, that's why I also added another reviewer :). The original revision got accepted and then I reverted and updated the patch/test to honor the Deserialize value (which was broken in the first version). I guess the fact that this got reviewed, landed, reverted and back into review caused some confusion

Also obligatory "friendly ping" on this :)

[vsapsai]

clang/lib/AST/ASTDumper.cpp

199

It is possible it will complicate the implementation too much but what if P.setDeserialize(Deserialize); is responsible for propagating Deserialize to its NodeDelegate?

[teemperor]

• Make setter propagate 'deserialize' to the node dumper (thanks Volodymyr!)

[vsapsai]

As long as JSON dumper still compiles, it looks good to me. Just have a few small nits.

clang/include/clang/AST/TextNodeDumper.h

46

Would it be better to make the default value the same as in ASTNodeTraverser? I.e.,

/// Indicates whether we should trigger deserialization of nodes that had
/// not already been loaded.
bool Deserialize = false;

clang/lib/AST/TextNodeDumper.cpp

1977–1980

The inconsistency that visually single-statement "if" branch has curly braces but "else" branch doesn't is grating. I understand a macro can expand into multiple statements but visually it looks like a single statement. Probably I would add braces to "else" as well.

clang/include/clang/AST/TextNodeDumper.h

class TextTreeStructure {
   llvm::SmallVector<std::function<void(bool IsLastChild)>, 32> Pending;
 
   /// Indicates whether we're at the top level.
   bool TopLevel = true;
 
   /// Indicates if we're handling the first child after entering a new depth.
   bool FirstChild = true;
 
+  /// Indicates if we can deserialize declarations from the ExternalASTSource.
+  bool Deserialize = true;
+
   /// Prefix for currently-being-dumped entity.
   std::string Prefix;
 
 public:
+  void setDeserialize(bool D) { Deserialize = D; }
+  bool getDeserialize() const { return Deserialize; }
+
   /// Add a child of the current node.  Calls DoAddChild without arguments
   template <typename Fn> void AddChild(Fn DoAddChild) {
     return AddChild("", DoAddChild);
   }
 
   /// Add a child of the current node with an optional label.
   /// Calls DoAddChild without arguments.
   template <typename Fn> void AddChild(StringRef Label, Fn DoAddChild) {

clang/lib/AST/ASTDumper.cpp

LLVM_DUMP_METHOD void Decl::dump(raw_ostream &OS, bool Deserialize,
   if (ADOF_JSON == Format) {
     JSONDumper P(OS, SM, Ctx, Ctx.getPrintingPolicy(),
                  &Ctx.getCommentCommandTraits());
     (void)Deserialize; // FIXME?
     P.Visit(this);
   } else {
     ASTDumper P(OS, Ctx, Ctx.getDiagnostics().getShowColors());
     P.setDeserialize(Deserialize);
+    P.doGetNodeDelegate().setDeserialize(Deserialize);
     P.Visit(this);
   }
 }
 
 LLVM_DUMP_METHOD void Decl::dumpColor() const {
   const ASTContext &Ctx = getASTContext();
   ASTDumper P(llvm::errs(), Ctx, /*ShowColors=*/true);
   P.Visit(this);

clang/lib/AST/TextNodeDumper.cpp

AddChild([=] {
         ColorScope Color(OS, ShowColors, DeclKindNameColor);
         OS << "Destructor";
       }
       FLAG(hasSimpleDestructor, simple);
       FLAG(hasIrrelevantDestructor, irrelevant);
       FLAG(hasTrivialDestructor, trivial);
       FLAG(hasNonTrivialDestructor, non_trivial);
       FLAG(hasUserDeclaredDestructor, user_declared);
+      // Avoid calls to the external source unless we are explicitly allowed
+      // to do so.
+      if (!D->hasExternalVisibleStorage() || getDeserialize()) {
         FLAG(hasConstexprDestructor, constexpr);
+      } else
+        OS << " maybe_constexpr";
       FLAG(needsImplicitDestructor, needs_implicit);
       FLAG(needsOverloadResolutionForDestructor, needs_overload_resolution);
       if (!D->needsOverloadResolutionForDestructor())
         FLAG(defaultedDestructorIsDeleted, defaulted_is_deleted);
     });
   });
 
   for (const auto &I : D->bases()) {

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

 // CHECK-NEXT:    |-DeclStmt {{.*}} <line:16:3, line:21:4>
 // CHECK-NEXT:    | `-CXXRecordDecl {{.*}} <line:16:3, line:21:3> line:16:10{{( imported)?}}{{( <undeserialized declarations>)?}} struct V 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:    |   | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    |   |-CXXRecordDecl {{.*}} <col:3, col:10> col:10{{( imported)?}} implicit struct V
 // CHECK-NEXT:    |   `-CXXMethodDecl {{.*}} <line:17:5, line:20:5> line:17:10{{( imported)?}} f 'void ()'
 // CHECK-NEXT:    |     `-CompoundStmt {{.*}} <col:14, line:20:5>
 // CHECK-NEXT:    |       |-LambdaExpr {{.*}} <line:18:7, col:15> '(lambda at {{.*}}ast-dump-lambda.cpp:18:7)'
 // CHECK-NEXT:    |       | |-CXXRecordDecl {{.*}} <col:7> col:7{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    |       | | |-DefinitionData lambda standard_layout trivially_copyable can_const_default_init
 // CHECK-NEXT:    |       | | | |-DefaultConstructor
 // 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    |       | | | |-MoveAssignment
-// CHECK-NEXT:    |       | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    |       | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    |       | | |-CXXMethodDecl {{.*}} <col:12, col:15> col:7{{( imported)?}} operator() 'auto () const -> auto' inline
 // CHECK-NEXT:    |       | | | `-CompoundStmt {{.*}} <col:14, col:15>
 // CHECK-NEXT:    |       | | `-FieldDecl {{.*}} <col:8> col:8{{( imported)?}} implicit 'V *'
 // CHECK-NEXT:    |       | |-ParenListExpr {{.*}} <col:8> 'NULL TYPE'
 // CHECK-NEXT:    |       | | `-CXXThisExpr {{.*}} <col:8> 'V *' this
 // CHECK-NEXT:    |       | `-CompoundStmt {{.*}} <col:14, col:15>
 // CHECK-NEXT:    |       `-LambdaExpr {{.*}} <line:19:7, col:16> '(lambda at {{.*}}ast-dump-lambda.cpp:19:7)'
 // CHECK-NEXT:    |         |-CXXRecordDecl {{.*}} <col:7> col:7{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    |         | |-DefinitionData lambda standard_layout trivially_copyable can_const_default_init
 // CHECK-NEXT:    |         | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    |         | | |-MoveAssignment
-// CHECK-NEXT:    |         | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    |         | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    |         | |-CXXMethodDecl {{.*}} <col:13, col:16> col:7{{( imported)?}} operator() 'auto () const -> auto' inline
 // CHECK-NEXT:    |         | | `-CompoundStmt {{.*}} <col:15, col:16>
 // CHECK-NEXT:    |         | `-FieldDecl {{.*}} <col:8> col:8{{( imported)?}} implicit 'V'
 // CHECK-NEXT:    |         |-ParenListExpr {{.*}} <col:8> 'NULL TYPE'
 // CHECK-NEXT:    |         | `-UnaryOperator {{.*}} <col:8> '<dependent type>' prefix '*' cannot overflow
 // CHECK-NEXT:    |         |   `-CXXThisExpr {{.*}} <col:8> 'V *' this
 // CHECK-NEXT:    |         `-CompoundStmt {{.*}} <col:15, col:16>
 // CHECK-NEXT:    |-DeclStmt {{.*}} <line:22:3, col:11>
 // CHECK-NEXT:    | |-VarDecl {{.*}} <col:3, col:7> col:7{{( imported)?}} referenced b 'int'
 // CHECK-NEXT:    | `-VarDecl {{.*}} <col:3, col:10> col:10{{( imported)?}} referenced c 'int'
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:23:3, col:9> '(lambda at {{.*}}ast-dump-lambda.cpp:23:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | |-CXXMethodDecl {{.*}} <col:6, col:9> col:3{{( imported)?}} operator() 'auto () const' inline
 // CHECK-NEXT:    | | | `-CompoundStmt {{.*}} <col:8, col:9>
 // CHECK-NEXT:    | | |-CXXConversionDecl {{.*}} <col:3, col:9> col:3{{( imported)?}} implicit constexpr operator auto (*)() 'auto (*() const noexcept)()' inline
 // CHECK-NEXT:    | | `-CXXMethodDecl {{.*}} <col:3, col:9> col:3{{( imported)?}} implicit __invoke 'auto ()' static inline
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:8, col:9>
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:24:3, col:19> '(lambda at {{.*}}ast-dump-lambda.cpp:24:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | |-CXXMethodDecl {{.*}} <col:16, col:19> col:3{{( imported)?}} operator() 'auto (int, ...) const' inline
 // CHECK-NEXT:    | | | |-ParmVarDecl {{.*}} <col:6, col:10> col:10{{( imported)?}} a 'int'
 // CHECK-NEXT:    | | | `-CompoundStmt {{.*}} <col:18, col:19>
 // CHECK-NEXT:    | | |-CXXConversionDecl {{.*}} <col:3, col:19> col:3{{( imported)?}} implicit constexpr operator auto (*)(int, ...) 'auto (*() const noexcept)(int, ...)' inline
 // CHECK-NEXT:    | | `-CXXMethodDecl {{.*}} <col:3, col:19> col:3{{( imported)?}} implicit __invoke 'auto (int, ...)' static inline
 // CHECK-NEXT:    | |   `-ParmVarDecl {{.*}} <col:6, col:10> col:10{{( imported)?}} a 'int'
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:18, col:19>
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:25:3, col:11> '(lambda at {{.*}}ast-dump-lambda.cpp:25:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda standard_layout trivially_copyable can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor
 // 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | |-CXXMethodDecl {{.*}} <col:8, col:11> col:3{{( imported)?}} operator() 'auto () const -> auto' inline
 // CHECK-NEXT:    | | | `-CompoundStmt {{.*}} <col:10, col:11>
 // CHECK-NEXT:    | | `-FieldDecl {{.*}} <col:4> col:4{{( imported)?}} implicit 'Ts...'
 // CHECK-NEXT:    | |-ParenListExpr {{.*}} <col:4> 'NULL TYPE'
 // CHECK-NEXT:    | | `-DeclRefExpr {{.*}} <col:4> 'Ts' lvalue ParmVar {{.*}} 'a' 'Ts...'
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:10, col:11>
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:26:3, col:8> '(lambda at {{.*}}ast-dump-lambda.cpp:26:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | `-CXXMethodDecl {{.*}} <col:5, col:8> col:3{{( imported)?}} operator() 'auto () const -> auto' inline
 // CHECK-NEXT:    | |   `-CompoundStmt {{.*}} <col:7, col:8>
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:7, col:8>
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:27:3, col:19> '(lambda at {{.*}}ast-dump-lambda.cpp:27:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | `-CXXMethodDecl {{.*}} <col:5, col:19> col:3{{( imported)?}} operator() 'auto () const -> auto' inline
 // CHECK-NEXT:    | |   `-CompoundStmt {{.*}} <col:7, col:19>
 // CHECK-NEXT:    | |     `-ReturnStmt {{.*}} <col:9, col:16>
 // CHECK-NEXT:    | |       `-DeclRefExpr {{.*}} <col:16> 'const int' lvalue Var {{.*}} 'b' 'int'
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:7, col:19>
 // CHECK-NEXT:    |   `-ReturnStmt {{.*}} <col:9, col:16>
 // CHECK-NEXT:    |     `-DeclRefExpr {{.*}} <col:16> 'const int' lvalue Var {{.*}} 'b' 'int'
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:28:3, col:8> '(lambda at {{.*}}ast-dump-lambda.cpp:28:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | `-CXXMethodDecl {{.*}} <col:5, col:8> col:3{{( imported)?}} operator() 'auto () const -> auto' inline
 // CHECK-NEXT:    | |   `-CompoundStmt {{.*}} <col:7, col:8>
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:7, col:8>
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:29:3, col:19> '(lambda at {{.*}}ast-dump-lambda.cpp:29:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | `-CXXMethodDecl {{.*}} <col:5, col:19> col:3{{( imported)?}} operator() 'auto () const -> auto' inline
 // CHECK-NEXT:    | |   `-CompoundStmt {{.*}} <col:7, col:19>
 // CHECK-NEXT:    | |     `-ReturnStmt {{.*}} <col:9, col:16>
 // CHECK-NEXT:    | |       `-DeclRefExpr {{.*}} <col:16> 'int' lvalue Var {{.*}} 'c' 'int'
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:7, col:19>
 // CHECK-NEXT:    |   `-ReturnStmt {{.*}} <col:9, col:16>
 // CHECK-NEXT:    |     `-DeclRefExpr {{.*}} <col:16> 'int' lvalue Var {{.*}} 'c' 'int'
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:30:3, col:27> '(lambda at {{.*}}ast-dump-lambda.cpp:30:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor
 // 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | |-CXXMethodDecl {{.*}} <col:9, col:27> col:3{{( imported)?}} operator() 'auto () const -> auto' inline
 // CHECK-NEXT:    | | | `-CompoundStmt {{.*}} <col:11, col:27>
 // CHECK-NEXT:    | | |   `-ReturnStmt {{.*}} <col:13, col:24>
 // CHECK-NEXT:    | | |     `-BinaryOperator {{.*}} <col:20, col:24> 'int' '+'
 // CHECK-NEXT:    | | |       |-ImplicitCastExpr {{.*}} <col:20> 'int' <LValueToRValue>
 // CHECK-NEXT:    | | |       | `-DeclRefExpr {{.*}} <col:20> 'const int' lvalue Var {{.*}} 'b' 'int'
 // CHECK-NEXT:    | | |       `-ImplicitCastExpr {{.*}} <col:24> 'int' <LValueToRValue>
 // CHECK-NEXT:    | | |         `-DeclRefExpr {{.*}} <col:24> 'int' lvalue Var {{.*}} 'c' 'int'

 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:31:3, col:19> '(lambda at {{.*}}ast-dump-lambda.cpp:31:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda standard_layout trivially_copyable can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor
 // 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | |-CXXMethodDecl {{.*}} <col:16, col:19> col:3{{( imported)?}} operator() 'auto () const -> auto' inline
 // CHECK-NEXT:    | | | `-CompoundStmt {{.*}} <col:18, col:19>
 // CHECK-NEXT:    | | |-FieldDecl {{.*}} <col:4> col:4{{( imported)?}} implicit 'Ts...'
 // CHECK-NEXT:    | | `-FieldDecl {{.*}} <col:10> col:10{{( imported)?}} implicit 'int':'int'
 // CHECK-NEXT:    | |-ParenListExpr {{.*}} <col:4> 'NULL TYPE'
 // CHECK-NEXT:    | | `-DeclRefExpr {{.*}} <col:4> 'Ts' lvalue ParmVar {{.*}} 'a' 'Ts...'
 // CHECK-NEXT:    | |-IntegerLiteral {{.*}} <col:14> 'int' 12
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:18, col:19>
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:32:3, col:19> '(lambda at {{.*}}ast-dump-lambda.cpp:32:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | |-CXXMethodDecl {{.*}} <col:8, col:19> col:3{{( imported)?}} constexpr operator() 'auto () const' inline
 // CHECK-NEXT:    | | | `-CompoundStmt {{.*}} <col:18, col:19>
 // CHECK-NEXT:    | | |-CXXConversionDecl {{.*}} <col:3, col:19> col:3{{( imported)?}} implicit constexpr operator auto (*)() 'auto (*() const noexcept)()' inline
 // CHECK-NEXT:    | | `-CXXMethodDecl {{.*}} <col:3, col:19> col:3{{( imported)?}} implicit __invoke 'auto ()' static inline
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:18, col:19>
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:33:3, col:17> '(lambda at {{.*}}ast-dump-lambda.cpp:33:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | |-CXXMethodDecl {{.*}} <col:8, col:17> col:3{{( imported)?}} operator() 'auto ()' inline
 // CHECK-NEXT:    | | | `-CompoundStmt {{.*}} <col:16, col:17>
 // CHECK-NEXT:    | | |-CXXConversionDecl {{.*}} <col:3, col:17> col:3{{( imported)?}} implicit constexpr operator auto (*)() 'auto (*() const noexcept)()' inline
 // CHECK-NEXT:    | | `-CXXMethodDecl {{.*}} <col:3, col:17> col:3{{( imported)?}} implicit __invoke 'auto ()' static inline
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:16, col:17>
 // CHECK-NEXT:    |-LambdaExpr {{.*}} <line:34:3, col:18> '(lambda at {{.*}}ast-dump-lambda.cpp:34:3)'
 // CHECK-NEXT:    | |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:    | | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:    | | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:    | | | |-MoveAssignment
-// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:    | | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:    | | |-CXXMethodDecl {{.*}} <col:8, col:18> col:3{{( imported)?}} operator() 'auto () const noexcept' inline
 // CHECK-NEXT:    | | | `-CompoundStmt {{.*}} <col:17, col:18>
 // CHECK-NEXT:    | | |-CXXConversionDecl {{.*}} <col:3, col:18> col:3{{( imported)?}} implicit constexpr operator auto (*)() noexcept 'auto (*() const noexcept)() noexcept' inline
 // CHECK-NEXT:    | | `-CXXMethodDecl {{.*}} <col:3, col:18> col:3{{( imported)?}} implicit __invoke 'auto () noexcept' static inline
 // CHECK-NEXT:    | `-CompoundStmt {{.*}} <col:17, col:18>
 // CHECK-NEXT:    `-LambdaExpr {{.*}} <line:35:3, col:27> '(lambda at {{.*}}ast-dump-lambda.cpp:35:3)'
 // CHECK-NEXT:      |-CXXRecordDecl {{.*}} <col:3> col:3{{( imported)?}} implicit{{( <undeserialized declarations>)?}} class definition
 // CHECK-NEXT:      | |-DefinitionData lambda empty standard_layout trivially_copyable literal can_const_default_init
 // CHECK-NEXT:      | | |-DefaultConstructor 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 trivial has_const_param needs_implicit implicit_has_const_param
 // CHECK-NEXT:      | | |-MoveAssignment
-// CHECK-NEXT:      | | `-Destructor simple irrelevant trivial needs_implicit
+// CHECK-NEXT:      | | `-Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 // CHECK-NEXT:      | |-CXXMethodDecl {{.*}} <col:11, col:27> col:3{{( imported)?}} operator() 'auto () const -> int' inline
 // CHECK-NEXT:      | | `-CompoundStmt {{.*}} <col:15, col:27>
 // CHECK-NEXT:      | |   `-ReturnStmt {{.*}} <col:17, col:24>
 // CHECK-NEXT:      | |     `-IntegerLiteral {{.*}} <col:24> 'int' 0
 // CHECK-NEXT:      | |-CXXConversionDecl {{.*}} <col:3, col:27> col:3{{( imported)?}} implicit constexpr operator int (*)() 'auto (*() const noexcept)() -> int' inline
 // CHECK-NEXT:      | `-CXXMethodDecl {{.*}} <col:3, col:27> col:3{{( imported)?}} implicit __invoke 'auto () -> int' static inline
 // CHECK-NEXT:      `-CompoundStmt {{.*}} <col:15, col:27>
 // CHECK-NEXT:        `-ReturnStmt {{.*}} <col:17, col:24>
 // CHECK-NEXT:          `-IntegerLiteral {{.*}} <col:24> 'int' 0

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

 struct A {
   // CHECK: CXXRecordDecl 0x{{[^ ]*}} prev 0x{{[^ ]*}} <line:[[@LINE-1]]:1, line:[[@LINE+32]]:1> line:[[@LINE-1]]:8 struct A definition
   // CHECK-NEXT: DefinitionData pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 
   // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <col:1, col:8> col:8 implicit struct A
   int a;
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:7> col:7 a 'int'
   int b, c;
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:7> col:7 b 'int'
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <col:3, col:10> col:10 c 'int'
   int d : 12;

 struct C {
   // CHECK: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:1, line:[[@LINE+66]]:1> line:[[@LINE-1]]:8 struct C definition
   // CHECK-NEXT: DefinitionData pass_in_registers aggregate standard_layout trivially_copyable pod trivial literal has_variant_members
   // 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 
   // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <col:1, col:8> col:8 implicit struct C
   struct {
     // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, line:[[@LINE+10]]:3> line:[[@LINE-1]]:3 struct definition
     // CHECK-NEXT: DefinitionData pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
     int a;
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:9> col:9 a 'int'
   } b;
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-12]]:3, line:[[@LINE-1]]:5> col:5 b 'struct (anonymous struct at {{.*}}:[[@LINE-12]]:3)':'C::(anonymous struct at {{.*}}:[[@LINE-12]]:3)'
 
   union {
     // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, line:[[@LINE+12]]:3> line:[[@LINE-1]]:3 union definition
     // CHECK-NEXT: DefinitionData is_anonymous pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
     int c;
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:9> col:9 c 'int'
     float d;
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:11> col:11 d 'float'
   };
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-14]]:3> col:3 implicit 'C::(anonymous union at {{.*}}:[[@LINE-14]]:3)'
   // CHECK-NEXT: IndirectFieldDecl 0x{{[^ ]*}} <line:[[@LINE-6]]:9> col:9 implicit c 'int'
   // CHECK-NEXT: Field 0x{{[^ ]*}} '' 'C::(anonymous union at {{.*}}:[[@LINE-16]]:3)'
   // CHECK-NEXT: Field 0x{{[^ ]*}} 'c' 'int'
   // CHECK-NEXT: IndirectFieldDecl 0x{{[^ ]*}} <line:[[@LINE-7]]:11> col:11 implicit d 'float'
   // CHECK-NEXT: Field 0x{{[^ ]*}} '' 'C::(anonymous union at {{.*}}:[[@LINE-19]]:3)'
   // CHECK-NEXT: Field 0x{{[^ ]*}} 'd' 'float'
 
   struct {
     // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, line:[[@LINE+11]]:3> line:[[@LINE-1]]:3 struct definition
     // CHECK-NEXT: DefinitionData is_anonymous pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
     int e, f;
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:9> col:9 e 'int'
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <col:5, col:12> col:12 f 'int'
   };
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-13]]:3> col:3 implicit 'C::(anonymous struct at {{.*}}:[[@LINE-13]]:3)'
   // CHECK-NEXT: IndirectFieldDecl 0x{{[^ ]*}} <line:[[@LINE-5]]:9> col:9 implicit e 'int'
   // CHECK-NEXT: Field 0x{{[^ ]*}} '' 'C::(anonymous struct at {{.*}}:[[@LINE-15]]:3)'
   // CHECK-NEXT: Field 0x{{[^ ]*}} 'e' 'int'
   // CHECK-NEXT: IndirectFieldDecl 0x{{[^ ]*}} <col:12> col:12 implicit f 'int'
   // CHECK-NEXT: Field 0x{{[^ ]*}} '' 'C::(anonymous struct at {{.*}}:[[@LINE-18]]:3)'
   // CHECK-NEXT: Field 0x{{[^ ]*}} 'f' 'int'
 };
 
 struct D {
   // CHECK: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:1, line:[[@LINE+16]]:1> line:[[@LINE-1]]:8 struct D definition
   // CHECK-NEXT: DefinitionData pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 
   // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <col:1, col:8> col:8 implicit struct D
   int a;
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:7> col:7 a 'int'
   int b[10];
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:11> col:7 b 'int [10]'
   int c[];
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:9> col:7 c 'int []'
 };
 
 union E;
 // CHECK: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:1, col:7> col:7 union E
 
 union F;
 // CHECK: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:1, col:7> col:7 union F
 
 union E {
   // CHECK: CXXRecordDecl 0x{{[^ ]*}} prev 0x{{[^ ]*}} <line:[[@LINE-1]]:1, line:[[@LINE+32]]:1> line:[[@LINE-1]]:7 union E definition
   // CHECK-NEXT: DefinitionData pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 
   // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <col:1, col:7> col:7 implicit union E
   int a;
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:7> col:7 a 'int'
   int b, c;
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:7> col:7 b 'int'
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <col:3, col:10> col:10 c 'int'
   int d : 12;

 union G {
   // CHECK: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:1, line:[[@LINE+71]]:1> line:[[@LINE-1]]:7 union G definition
   // CHECK-NEXT: DefinitionData pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 
   // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <col:1, col:7> col:7 implicit union G
   struct {
     // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, line:[[@LINE+11]]:3> line:[[@LINE-1]]:3 struct definition
     // CHECK-NEXT: DefinitionData pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 
     int a;
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:9> col:9 a 'int'
   } b;
   // FIXME: note that it talks about 'struct G' below; the same happens in
   // other cases with union G as well.
   // CHECK: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-15]]:3, line:[[@LINE-3]]:5> col:5 b 'struct (anonymous struct at {{.*}}:[[@LINE-15]]:3)':'G::(anonymous struct at {{.*}}:[[@LINE-15]]:3)'
 
   union {
     // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, line:[[@LINE+13]]:3> line:[[@LINE-1]]:3 union definition
     // CHECK-NEXT: DefinitionData is_anonymous pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 
     int c;
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:9> col:9 c 'int'
     float d;
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:11> col:11 d 'float'
   };
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-15]]:3> col:3 implicit 'G::(anonymous union at {{.*}}:[[@LINE-15]]:3)'
   // CHECK-NEXT: IndirectFieldDecl 0x{{[^ ]*}} <line:[[@LINE-6]]:9> col:9 implicit c 'int'
   // CHECK-NEXT: Field 0x{{[^ ]*}} '' 'G::(anonymous union at {{.*}}:[[@LINE-17]]:3)'
   // CHECK-NEXT: Field 0x{{[^ ]*}} 'c' 'int'
   // CHECK-NEXT: IndirectFieldDecl 0x{{[^ ]*}} <line:[[@LINE-7]]:11> col:11 implicit d 'float'
   // CHECK-NEXT: Field 0x{{[^ ]*}} '' 'G::(anonymous union at {{.*}}:[[@LINE-20]]:3)'
   // CHECK-NEXT: Field 0x{{[^ ]*}} 'd' 'float'
 
   struct {
     // CHECK-NEXT: CXXRecordDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:3, line:[[@LINE+12]]:3> line:[[@LINE-1]]:3 struct definition
     // CHECK-NEXT: DefinitionData is_anonymous pass_in_registers aggregate standard_layout trivially_copyable pod 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: Destructor simple irrelevant trivial{{( maybe_constexpr)?}} needs_implicit
 
     int e, f;
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:9> col:9 e 'int'
     // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <col:5, col:12> col:12 f 'int'
   };
   // CHECK-NEXT: FieldDecl 0x{{[^ ]*}} <line:[[@LINE-14]]:3> col:3 implicit 'G::(anonymous struct at {{.*}}:[[@LINE-14]]:3)'
   // CHECK-NEXT: IndirectFieldDecl 0x{{[^ ]*}} <line:[[@LINE-5]]:9> col:9 implicit e 'int'
   // CHECK-NEXT: Field 0x{{[^ ]*}} '' 'G::(anonymous struct at {{.*}}:[[@LINE-16]]:3)'

clang/unittests/AST/ASTDumpTest.cpp

+//===- unittests/AST/ASTDumpTest.cpp --- Declaration tests ----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Tests Decl::dump().
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/Basic/Builtins.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/SourceManager.h"
+#include "gtest/gtest.h"
+
+using namespace clang;
+
+namespace clang {
+namespace ast {
+
+namespace {
+/// An ExternalASTSource that asserts if it is queried for information about
+/// any declaration.
+class TrappingExternalASTSource : public ExternalASTSource {
+  ~TrappingExternalASTSource() override = default;
+  bool FindExternalVisibleDeclsByName(const DeclContext *,
+                                      DeclarationName) override {
+    assert(false && "Unexpected call to FindExternalVisibleDeclsByName");
+    return true;
+  }
+
+  void FindExternalLexicalDecls(const DeclContext *,
+                                llvm::function_ref<bool(Decl::Kind)>,
+                                SmallVectorImpl<Decl *> &) override {
+    assert(false && "Unexpected call to FindExternalLexicalDecls");
+  }
+
+  void completeVisibleDeclsMap(const DeclContext *) override {
+    assert(false && "Unexpected call to completeVisibleDeclsMap");
+  }
+
+  void CompleteRedeclChain(const Decl *) override {
+    assert(false && "Unexpected call to CompleteRedeclChain");
+  }
+
+  void CompleteType(TagDecl *) override {
+    assert(false && "Unexpected call to CompleteType(Tag Decl*)");
+  }
+
+  void CompleteType(ObjCInterfaceDecl *) override {
+    assert(false && "Unexpected call to CompleteType(ObjCInterfaceDecl *)");
+  }
+};
+
+/// An ExternalASTSource that records which DeclContexts were queried so far.
+class RecordingExternalASTSource : public ExternalASTSource {
+public:
+  llvm::DenseSet<const DeclContext *> QueriedDCs;
+  ~RecordingExternalASTSource() override = default;
+
+  void FindExternalLexicalDecls(const DeclContext *DC,
+                                llvm::function_ref<bool(Decl::Kind)>,
+                                SmallVectorImpl<Decl *> &) override {
+    QueriedDCs.insert(DC);
+  }
+};
+
+
+class ASTDumpTestBase : public ::testing::Test {
+protected:
+  ASTDumpTestBase(clang::ExternalASTSource *Source)
+      : FileMgr(FileMgrOpts), DiagID(new DiagnosticIDs()),
+        Diags(DiagID, new DiagnosticOptions, new IgnoringDiagConsumer()),
+        SourceMgr(Diags, FileMgr), Idents(LangOpts, nullptr),
+        Ctxt(LangOpts, SourceMgr, Idents, Sels, Builtins) {
+    Ctxt.setExternalSource(Source);
+  }
+
+  FileSystemOptions FileMgrOpts;
+  FileManager FileMgr;
+  IntrusiveRefCntPtr<DiagnosticIDs> DiagID;
+  DiagnosticsEngine Diags;
+  SourceManager SourceMgr;
+  LangOptions LangOpts;
+  IdentifierTable Idents;
+  SelectorTable Sels;
+  Builtin::Context Builtins;
+  ASTContext Ctxt;
+};
+
+/// Tests that Decl::dump doesn't load additional declarations from the
+/// ExternalASTSource.
+class NoDeserializeTest : public ASTDumpTestBase {
+protected:
+  NoDeserializeTest() : ASTDumpTestBase(new TrappingExternalASTSource()) {}
+};
+
+/// Tests which declarations Decl::dump deserializes;
+class DeserializeTest : public ASTDumpTestBase {
+protected:
+  DeserializeTest() : ASTDumpTestBase(Recorder = new RecordingExternalASTSource()) {}
+  RecordingExternalASTSource *Recorder;
+};
+} // unnamed namespace
+
+/// Set all flags that activate queries to the ExternalASTSource.
+static void setExternalStorageFlags(DeclContext *DC) {
+  DC->setHasExternalLexicalStorage();
+  DC->setHasExternalVisibleStorage();
+  DC->setMustBuildLookupTable();
+}
+
+/// Dumps the given Decl.
+static void dumpDecl(Decl *D, bool Deserialize) {
+  // Try dumping the decl which shouldn't trigger any calls to the
+  // ExternalASTSource.
+
+  std::string Out;
+  llvm::raw_string_ostream OS(Out);
+  D->dump(OS, Deserialize);
+}
+
+TEST_F(NoDeserializeTest, DumpObjCInterfaceDecl) {
+  // Define an Objective-C interface.
+  ObjCInterfaceDecl *I = ObjCInterfaceDecl::Create(
+      Ctxt, Ctxt.getTranslationUnitDecl(), SourceLocation(),
+      &Ctxt.Idents.get("c"), nullptr, nullptr);
+  Ctxt.getTranslationUnitDecl()->addDecl(I);
+
+  setExternalStorageFlags(I);
+  dumpDecl(I, /*Deserialize*/false);
+}
+
+TEST_F(NoDeserializeTest, DumpRecordDecl) {
+  // Define a struct.
+  RecordDecl *R = RecordDecl::Create(
+      Ctxt, TagDecl::TagKind::TTK_Class, Ctxt.getTranslationUnitDecl(),
+      SourceLocation(), SourceLocation(), &Ctxt.Idents.get("c"));
+  R->startDefinition();
+  R->completeDefinition();
+  Ctxt.getTranslationUnitDecl()->addDecl(R);
+
+  setExternalStorageFlags(R);
+  dumpDecl(R, /*Deserialize*/false);
+}
+
+TEST_F(NoDeserializeTest, DumpCXXRecordDecl) {
+  // Define a class.
+  CXXRecordDecl *R = CXXRecordDecl::Create(
+      Ctxt, TagDecl::TagKind::TTK_Class, Ctxt.getTranslationUnitDecl(),
+      SourceLocation(), SourceLocation(), &Ctxt.Idents.get("c"));
+  R->startDefinition();
+  R->completeDefinition();
+  Ctxt.getTranslationUnitDecl()->addDecl(R);
+
+  setExternalStorageFlags(R);
+  dumpDecl(R, /*Deserialize*/false);
+}
+
+TEST_F(DeserializeTest, DumpCXXRecordDecl) {
+  // Define a class.
+  CXXRecordDecl *R = CXXRecordDecl::Create(
+      Ctxt, TagDecl::TagKind::TTK_Class, Ctxt.getTranslationUnitDecl(),
+      SourceLocation(), SourceLocation(), &Ctxt.Idents.get("c"));
+  R->startDefinition();
+  R->completeDefinition();
+  Ctxt.getTranslationUnitDecl()->addDecl(R);
+
+  setExternalStorageFlags(R);
+  // Check that our record gets deserialized while dumping.
+  EXPECT_FALSE(Recorder->QueriedDCs.contains(R));
+  dumpDecl(R, /*Deserialize*/true);
+  EXPECT_TRUE(Recorder->QueriedDCs.contains(R));
+}
+
+} // end namespace ast
+} // end namespace clang

clang/unittests/AST/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   FrontendOpenMP
   Support
   )
 
 
 add_clang_unittest(ASTTests
   ASTContextParentMapTest.cpp
+  ASTDumpTest.cpp
   ASTImporterFixtures.cpp
   ASTImporterTest.cpp
   ASTImporterGenericRedeclTest.cpp
   ASTImporterODRStrategiesTest.cpp
   ASTImporterVisibilityTest.cpp
   ASTTraverserTest.cpp
   ASTTypeTraitsTest.cpp
   ASTTraverserTest.cpp