Ignore implicit nodes in IgnoreUnlessSpelledInSource mode

[steveire]

Summary

Update the ASTNodeTraverser to dump only nodes spelled in source. There
are only a few which need to be handled, but Decl nodes for which
isImplicit() is true are handled together.

Update the RAV instances used in ASTMatchFinder to ignore the nodes too.
As with handling of template instantiations, it is necessary to allow
the RAV to process the implicit nodes because they need to be visitable
before the first traverse() matcher is encountered. An exception to
this is in the MatchChildASTVisitor, because we sometimes wish to make a
node matchable but make its children not-matchable. This is the case
for defaulted CXXMethodDecls for example.

This change accounts for handling nodes not spelled in source when using
direct matching of nodes, and when using the has() and hasDescendant()
matchers. Other matchers such as
cxxRecordDecl(hasMethod(cxxMethodDecl())) still succeed for
compiler-generated methods for example after this change. Updating the
implementations of hasMethod() and other matchers is for a follow-up
patch.

[steveire]

Update

[steveire]

Update

[steveire]

Update

[steveire]

Update

[aaron.ballman]

Thank you for this, I think it's mostly looking good!

clang/include/clang/AST/ASTNodeTraverser.h

88

Similar to the feedback on D90984, I think this will do the wrong thing for the weird traversal mode for ignoring parens and implicit casts. It should probably be checking for Traversal == TK_IgnoreUnlessSpelledInSource here.

192

Same issue here.

410

Same here. I'll stop calling these out -- can you double check all the uses of Traversal != TK_AsIs?

733

If we're in AsIs mode, don't we still want to match on some parts of the range-based for loop because they are spelled in source (like the body of the loop or the range-expression, etc)?

The test behavior looks reasonable around this, so I suspect I'm just misunderstanding this change.

742

This be const auto * or at least auto *.

clang/lib/ASTMatchers/ASTMatchFinder.cpp

152

Similar issue here about traversal mode.

1084

Spelling this as bool would not be amiss (same below, given how trivial it is to spell the type out).

1109

bool here as well, please.

1158

Here too.

clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp

2503

Can you add one more test for the body like cxxForRangeStmt(hasBody(compoundStmt())) which should match in both modes?

[steveire]

Update

[aaron.ballman]

LGTM, thank you!

clang/lib/ASTMatchers/ASTMatchFinder.cpp

164

Good catch!

[thakis]

(usual procedure is to revert while investigating test failures instead of commenting out the tests)

[leonardchan]

Hi. I suspect it might be this patch or D90984 that might be leading to the test failure we're seeing on our arm64 builders

FAIL: Clang-Unit :: AST/./ASTTests/Traverse.IgnoreUnlessSpelledInSourceImplicit (15871 of 26886)
******************** TEST 'Clang-Unit :: AST/./ASTTests/Traverse.IgnoreUnlessSpelledInSourceImplicit' FAILED ********************
Note: Google Test filter = Traverse.IgnoreUnlessSpelledInSourceImplicit
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from Traverse
[ RUN      ] Traverse.IgnoreUnlessSpelledInSourceImplicit
clang/unittests/AST/ASTTraverserTest.cpp:1114: Failure
      Expected: dumpASTString(TK_AsIs, TUDecl)
      Which is: "\nTranslationUnitDecl\n|-TypedefDecl '__int128_t'\n| ...

Would you mind taking a look? Thanks.

Builder link: https://luci-milo.appspot.com/p/fuchsia/builders/ci/clang-linux-arm64/b8863364626069720736

[RKSimon]

@stephenkelly This is breaking a large number of bots - please can you revert your patch series to get things green again?

[steveire]

I've removed the offending test (which in this case is the correct fix - it is not a temporary fix).

@RKSimon Is there some way I can see what is causing the failures on the other platforms? Was it because of this test? How can I monitor this? I knew how to see it in lab.llvm.org, but it seems things are missing or moved in the new buildbot interface. I otherwise have no way of knowing what problems were caused by this, and whether a new version of this patch fixes the problems?

clang/docs/ReleaseNotes.rst

 These are major changes to the build system that have happened since the 11.0.0
 release of Clang. Users of the build system should adjust accordingly.
 
 - ...
 
 AST Matchers
 ------------
 
-- ...
+- The behavior of TK_IgnoreUnlessSpelledInSource with the traverse() matcher
+  has been changed to no longer match on template instantiations or on
+  implicit nodes which are not spelled in the source.
 
 clang-format
 ------------
 
 - Option ``BitFieldColonSpacing`` has been added that decides how
   space should be added around identifier, colon and bit-width in
   bitfield definitions.
 

clang/include/clang/AST/ASTNodeTraverser.h

 public:
   void setDeserialize(bool D) { Deserialize = D; }
   bool getDeserialize() const { return Deserialize; }
 
   void SetTraversalKind(TraversalKind TK) { Traversal = TK; }
   TraversalKind GetTraversalKind() const { return Traversal; }
 
   void Visit(const Decl *D) {
+    if (Traversal == TK_IgnoreUnlessSpelledInSource && D->isImplicit())
+      return;
+
     getNodeDelegate().AddChild([=] {
       getNodeDelegate().Visit(D);
       if (!D)
         return;
 
       ConstDeclVisitor<Derived>::Visit(D);
 
       for (const auto &A : D->attrs())
getNodeDelegate().AddChild(Label, [=] {
       }
 
       ConstStmtVisitor<Derived>::Visit(S);
 
       // Some statements have custom mechanisms for dumping their children.
       if (isa<DeclStmt>(S) || isa<GenericSelectionExpr>(S))
         return;
 
-      if (isa<LambdaExpr>(S) && Traversal == TK_IgnoreUnlessSpelledInSource)
+      if (Traversal == TK_IgnoreUnlessSpelledInSource &&
+          isa<LambdaExpr, CXXForRangeStmt, CallExpr>(S))
         return;
 
       for (const Stmt *SubStmt : S->children())
         Visit(SubStmt);
     });
   }
 
   void Visit(QualType T) {
public:
   void Visit(const Attr *A) {
     getNodeDelegate().AddChild([=] {
       getNodeDelegate().Visit(A);
       ConstAttrVisitor<Derived>::Visit(A);
     });
   }
 
   void Visit(const CXXCtorInitializer *Init) {
+    if (Traversal == TK_IgnoreUnlessSpelledInSource && !Init->isWritten())
+      return;
     getNodeDelegate().AddChild([=] {
       getNodeDelegate().Visit(Init);
       Visit(Init->getInit());
     });
   }
 
   void Visit(const TemplateArgument &A, SourceRange R = {},
              const Decl *From = nullptr, const char *Label = nullptr) {
void VisitFunctionDecl(const FunctionDecl *D) {
 
     if (D->param_begin())
       for (const auto *Parameter : D->parameters())
         Visit(Parameter);
 
     if (const Expr *TRC = D->getTrailingRequiresClause())
       Visit(TRC);
 
+    if (Traversal == TK_IgnoreUnlessSpelledInSource && D->isDefaulted())
+      return;
+
     if (const auto *C = dyn_cast<CXXConstructorDecl>(D))
       for (const auto *I : C->inits())
         Visit(I);
 
     if (D->doesThisDeclarationHaveABody())
       Visit(D->getBody());
   }
 
   void VisitFieldDecl(const FieldDecl *D) {
     if (D->isBitField())
       Visit(D->getBitWidth());
     if (Expr *Init = D->getInClassInitializer())
       Visit(Init);
   }
 
   void VisitVarDecl(const VarDecl *D) {
+    if (Traversal == TK_IgnoreUnlessSpelledInSource && D->isCXXForRangeDecl())
+      return;
+
     if (D->hasInit())
       Visit(D->getInit());
   }
 
   void VisitDecompositionDecl(const DecompositionDecl *D) {
     VisitVarDecl(D);
     for (const auto *B : D->bindings())
       Visit(B);
void VisitSubstNonTypeTemplateParmPackExpr(
     Visit(E->getArgumentPack());
   }
 
   void VisitObjCAtCatchStmt(const ObjCAtCatchStmt *Node) {
     if (const VarDecl *CatchParam = Node->getCatchParamDecl())
       Visit(CatchParam);
   }
 
+  void VisitCXXForRangeStmt(const CXXForRangeStmt *Node) {
+    if (Traversal == TK_IgnoreUnlessSpelledInSource) {
+      Visit(Node->getInit());
+      Visit(Node->getLoopVariable());
+      Visit(Node->getRangeInit());
+      Visit(Node->getBody());
+    }
+  }
+
+  void VisitCallExpr(const CallExpr *Node) {
+    for (const auto *Child :
+         make_filter_range(Node->children(), [this](const Stmt *Child) {
+           if (Traversal != TK_IgnoreUnlessSpelledInSource)
+             return false;
+           return !isa<CXXDefaultArgExpr>(Child);
+         })) {
+      Visit(Child);
+    }
+  }
+
   void VisitExpressionTemplateArgument(const TemplateArgument &TA) {
     Visit(TA.getAsExpr());
   }
 
   void VisitTypeTemplateArgument(const TemplateArgument &TA) {
     Visit(TA.getAsType());
   }
 

clang/lib/ASTMatchers/ASTMatchFinder.cpp

public:
   typedef RecursiveASTVisitor<MatchChildASTVisitor> VisitorBase;
 
   // Creates an AST visitor that matches 'matcher' on all children or
   // descendants of a traversed node. max_depth is the maximum depth
   // to traverse: use 1 for matching the children and INT_MAX for
   // matching the descendants.
   MatchChildASTVisitor(const DynTypedMatcher *Matcher, ASTMatchFinder *Finder,
                        BoundNodesTreeBuilder *Builder, int MaxDepth,
-                       TraversalKind Traversal, ASTMatchFinder::BindKind Bind)
+                       TraversalKind Traversal, bool IgnoreImplicitChildren,
+                       ASTMatchFinder::BindKind Bind)
       : Matcher(Matcher), Finder(Finder), Builder(Builder), CurrentDepth(0),
-        MaxDepth(MaxDepth), Traversal(Traversal), Bind(Bind), Matches(false) {}
+        MaxDepth(MaxDepth), Traversal(Traversal),
+        IgnoreImplicitChildren(IgnoreImplicitChildren), Bind(Bind),
+        Matches(false) {}
 
   // Returns true if a match is found in the subtree rooted at the
   // given AST node. This is done via a set of mutually recursive
   // functions. Here's how the recursion is done (the  *wildcard can
   // actually be Decl, Stmt, or Type):
   //
   //   - Traverse(node) calls BaseTraverse(node) when it needs
   //     to visit the descendants of node.
bool findMatch(const DynTypedNode &DynNode) {
 
     return Matches;
   }
 
   // The following are overriding methods from the base visitor class.
   // They are public only to allow CRTP to work. They are *not *part
   // of the public API of this class.
   bool TraverseDecl(Decl *DeclNode) {
+
+    if (DeclNode && DeclNode->isImplicit() &&
+        Finder->isTraversalIgnoringImplicitNodes())
+      return baseTraverse(*DeclNode);
+
     ScopedIncrement ScopedDepth(&CurrentDepth);
     return (DeclNode == nullptr) || traverse(*DeclNode);
   }
 
   Stmt *getStmtToTraverse(Stmt *StmtNode) {
     Stmt *StmtToTraverse = StmtNode;
     if (auto *ExprNode = dyn_cast_or_null<Expr>(StmtNode)) {
       auto *LambdaNode = dyn_cast_or_null<LambdaExpr>(StmtNode);
       if (LambdaNode && Finder->isTraversalIgnoringImplicitNodes())
         StmtToTraverse = LambdaNode;
       else
         StmtToTraverse =
             Finder->getASTContext().getParentMapContext().traverseIgnored(
                 ExprNode);
     }
     if (Traversal == TraversalKind::TK_IgnoreImplicitCastsAndParentheses) {
       if (Expr *ExprNode = dyn_cast_or_null<Expr>(StmtNode))
         StmtToTraverse = ExprNode->IgnoreParenImpCasts();
     }
     return StmtToTraverse;
   }
 
   bool TraverseStmt(Stmt *StmtNode, DataRecursionQueue *Queue = nullptr) {
     // If we need to keep track of the depth, we can't perform data recursion.
     if (CurrentDepth == 0 || (CurrentDepth <= MaxDepth && MaxDepth < INT_MAX))
       Queue = nullptr;
 
     ScopedIncrement ScopedDepth(&CurrentDepth);
     Stmt *StmtToTraverse = getStmtToTraverse(StmtNode);
     if (!StmtToTraverse)
       return true;
+
+    if (IgnoreImplicitChildren && isa<CXXDefaultArgExpr>(StmtNode))
+      return true;
+
     if (!match(*StmtToTraverse))
       return false;
     return VisitorBase::TraverseStmt(StmtToTraverse, Queue);
   }
   // We assume that the QualType and the contained type are on the same
   // hierarchy level. Thus, we try to match either of them.
   bool TraverseType(QualType TypeNode) {
     if (TypeNode.isNull())
bool TraverseLambdaExpr(LambdaExpr *Node) {
 
     if (!match(*Node->getBody()))
       return false;
 
     return true;
   }
 
   bool shouldVisitTemplateInstantiations() const { return true; }
-  bool shouldVisitImplicitCode() const { return true; }
+  bool shouldVisitImplicitCode() const { return !IgnoreImplicitChildren; }
 
 private:
   // Used for updating the depth during traversal.
   struct ScopedIncrement {
     explicit ScopedIncrement(int *Depth) : Depth(Depth) { ++(*Depth); }
     ~ScopedIncrement() { --(*Depth); }
 
    private:
private:
 
   const DynTypedMatcher *const Matcher;
   ASTMatchFinder *const Finder;
   BoundNodesTreeBuilder *const Builder;
   BoundNodesTreeBuilder ResultBindings;
   int CurrentDepth;
   const int MaxDepth;
   const TraversalKind Traversal;
+  const bool IgnoreImplicitChildren;
   const ASTMatchFinder::BindKind Bind;
   bool Matches;
 };
 
 // Controls the outermost traversal of the AST and allows to match multiple
 // matchers.
 class MatchASTVisitor : public RecursiveASTVisitor<MatchASTVisitor>,
                         public ASTMatchFinder {
bool memoizedMatchesRecursively(const DynTypedNode &Node, ASTContext &Ctx,
     return CachedResult.ResultOfMatch;
   }
 
   // Matches children or descendants of 'Node' with 'BaseMatcher'.
   bool matchesRecursively(const DynTypedNode &Node,
                           const DynTypedMatcher &Matcher,
                           BoundNodesTreeBuilder *Builder, int MaxDepth,
                           TraversalKind Traversal, BindKind Bind) {
-    bool ScopedTraversal = TraversingASTNodeNotSpelledInSource;
+    bool ScopedTraversal = TraversingASTNodeNotSpelledInSource ||
+                           TraversingASTChildrenNotSpelledInSource;
 
-    if (const auto *CTSD = Node.get<ClassTemplateSpecializationDecl>()) {
-      int SK = CTSD->getSpecializationKind();
-      if (SK == TSK_ExplicitInstantiationDeclaration ||
-          SK == TSK_ExplicitInstantiationDefinition)
+    bool IgnoreImplicitChildren = false;
+
+    if (isTraversalIgnoringImplicitNodes()) {
+      IgnoreImplicitChildren = true;
+      if (Node.get<CXXForRangeStmt>())
         ScopedTraversal = true;
     }
 
     ASTNodeNotSpelledInSourceScope RAII(this, ScopedTraversal);
 
-    MatchChildASTVisitor Visitor(
-      &Matcher, this, Builder, MaxDepth, Traversal, Bind);
+    MatchChildASTVisitor Visitor(&Matcher, this, Builder, MaxDepth, Traversal,
+                                 IgnoreImplicitChildren, Bind);
     return Visitor.findMatch(Node);
   }
 
   bool classIsDerivedFrom(const CXXRecordDecl *Declaration,
                           const Matcher<NamedDecl> &Base,
                           BoundNodesTreeBuilder *Builder,
                           bool Directly) override;
 
public:
   bool TraverseTemplateInstantiations(FunctionTemplateDecl *D) {
     ASTNodeNotSpelledInSourceScope RAII(this, true);
     return RecursiveASTVisitor<MatchASTVisitor>::TraverseTemplateInstantiations(
         D);
   }
 
 private:
   bool TraversingASTNodeNotSpelledInSource = false;
+  bool TraversingASTChildrenNotSpelledInSource = false;
 
   struct ASTNodeNotSpelledInSourceScope {
     ASTNodeNotSpelledInSourceScope(MatchASTVisitor *V, bool B)
         : MV(V), MB(V->TraversingASTNodeNotSpelledInSource) {
       V->TraversingASTNodeNotSpelledInSource = B;
     }
     ~ASTNodeNotSpelledInSourceScope() {
       MV->TraversingASTNodeNotSpelledInSource = MB;
     }
 
   private:
     MatchASTVisitor *MV;
     bool MB;
   };
 
+  struct ASTChildrenNotSpelledInSource {
+    ASTChildrenNotSpelledInSource(MatchASTVisitor *V, bool B)
+        : MV(V), MB(V->TraversingASTChildrenNotSpelledInSource) {
+      V->TraversingASTChildrenNotSpelledInSource = B;
+    }
+    ~ASTChildrenNotSpelledInSource() {
+      MV->TraversingASTChildrenNotSpelledInSource = MB;
+    }
+
+  private:
+    MatchASTVisitor *MV;
+    bool MB;
+  };
+
   class TimeBucketRegion {
   public:
     TimeBucketRegion() : Bucket(nullptr) {}
     ~TimeBucketRegion() { setBucket(nullptr); }
 
     /// Start timing for \p NewBucket.
     ///
     /// If there was a bucket already set, it will finish the timing for that
bool MatchASTVisitor::objcClassIsDerivedFrom(
 
   return false;
 }
 
 bool MatchASTVisitor::TraverseDecl(Decl *DeclNode) {
   if (!DeclNode) {
     return true;
   }
+
+  bool ScopedTraversal =
+      TraversingASTNodeNotSpelledInSource || DeclNode->isImplicit();
+  bool ScopedChildren = TraversingASTChildrenNotSpelledInSource;
+
+  if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(DeclNode)) {
+    auto SK = CTSD->getSpecializationKind();
+    if (SK == TSK_ExplicitInstantiationDeclaration ||
+        SK == TSK_ExplicitInstantiationDefinition)
+      ScopedChildren = true;
+  } else if (const auto *FD = dyn_cast<FunctionDecl>(DeclNode)) {
+    if (FD->isDefaulted())
+      ScopedChildren = true;
+  }
+
+  ASTNodeNotSpelledInSourceScope RAII1(this, ScopedTraversal);
+  ASTChildrenNotSpelledInSource RAII2(this, ScopedChildren);
+
   match(*DeclNode);
   return RecursiveASTVisitor<MatchASTVisitor>::TraverseDecl(DeclNode);
 }
 
 bool MatchASTVisitor::TraverseStmt(Stmt *StmtNode, DataRecursionQueue *Queue) {
   if (!StmtNode) {
     return true;
   }
+  bool ScopedTraversal = TraversingASTNodeNotSpelledInSource ||
+                         TraversingASTChildrenNotSpelledInSource;
+
+  ASTNodeNotSpelledInSourceScope RAII(this, ScopedTraversal);
   match(*StmtNode);
   return RecursiveASTVisitor<MatchASTVisitor>::TraverseStmt(StmtNode, Queue);
 }
 
 bool MatchASTVisitor::TraverseType(QualType TypeNode) {
   match(TypeNode);
   return RecursiveASTVisitor<MatchASTVisitor>::TraverseType(TypeNode);
 }
return
       RecursiveASTVisitor<MatchASTVisitor>::TraverseNestedNameSpecifierLoc(NNS);
 }
 
 bool MatchASTVisitor::TraverseConstructorInitializer(
     CXXCtorInitializer *CtorInit) {
   if (!CtorInit)
     return true;
 
+  bool ScopedTraversal = TraversingASTNodeNotSpelledInSource ||
+                         TraversingASTChildrenNotSpelledInSource;
+
+  if (!CtorInit->isWritten())
+    ScopedTraversal = true;
+
+  ASTNodeNotSpelledInSourceScope RAII1(this, ScopedTraversal);
+
   match(*CtorInit);
 
   return RecursiveASTVisitor<MatchASTVisitor>::TraverseConstructorInitializer(
       CtorInit);
 }
 
 bool MatchASTVisitor::TraverseTemplateArgumentLoc(TemplateArgumentLoc Loc) {
   match(Loc);

clang/unittests/AST/ASTTraverserTest.cpp

public:
   void Visit(const Decl *D) {
     OS << D->getDeclKindName() << "Decl";
     if (auto *ND = dyn_cast<NamedDecl>(D)) {
       OS << " '" << ND->getDeclName() << "'";
     }
   }
 
   void Visit(const Stmt *S) {
+    if (!S) {
+      OS << "<<<NULL>>>";
+      return;
+    }
     OS << S->getStmtClassName();
     if (auto *E = dyn_cast<DeclRefExpr>(S)) {
       OS << " '" << E->getDecl()->getDeclName() << "'";
     }
   }
 
   void Visit(QualType QT) {
     OS << "QualType " << QT.split().Quals.getAsString();
   }
 
   void Visit(const Type *T) { OS << T->getTypeClassName() << "Type"; }
 
   void Visit(const comments::Comment *C, const comments::FullComment *FC) {
     OS << C->getCommentKindName();
   }
 
-  void Visit(const CXXCtorInitializer *Init) { OS << "CXXCtorInitializer"; }
+  void Visit(const CXXCtorInitializer *Init) {
+    OS << "CXXCtorInitializer";
+    if (const auto *F = Init->getAnyMember()) {
+      OS << " '" << F->getNameAsString() << "'";
+    } else if (auto const *TSI = Init->getTypeSourceInfo()) {
+      OS << " '" << TSI->getType().getAsString() << "'";
+    }
+  }
 
   void Visit(const Attr *A) {
     switch (A->getKind()) {
 #define ATTR(X)                                                                \
   case attr::X:                                                                \
     OS << #X;                                                                  \
     break;
 #include "clang/Basic/AttrList.inc"
)cpp";
     EXPECT_EQ(dumpASTString(A), expectedString);
   }
 
   auto *CTor = dyn_cast<CXXConstructorDecl>(CTorFunc);
   const CXXCtorInitializer *Init = *CTor->init_begin();
 
   verifyWithDynNode(Init,
                     R"cpp(
-CXXCtorInitializer
+CXXCtorInitializer 'm_number'
 `-IntegerLiteral
 )cpp");
 
   const comments::FullComment *Comment =
       AST->getASTContext().getLocalCommentForDeclUncached(CTorFunc);
   {
     std::string expectedString = R"cpp(
 FullComment

 | `-UnaryOperator
 |   `-CXXThisExpr
 `-CompoundStmt
 )cpp";
     EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource, L), Expected);
   }
 }
 
+TEST(Traverse, IgnoreUnlessSpelledInSourceImplicit) {
+  {
+    auto AST = buildASTFromCode(R"cpp(
+int i = 0;
+)cpp");
+    const auto *TUDecl = AST->getASTContext().getTranslationUnitDecl();
+
+#if _WIN32
+    EXPECT_EQ(dumpASTString(TK_AsIs, TUDecl),
+              R"cpp(
+TranslationUnitDecl
+|-CXXRecordDecl '_GUID'
+| `-TypeVisibilityAttr
+|-TypedefDecl '__int128_t'
+| `-BuiltinType
+|-TypedefDecl '__uint128_t'
+| `-BuiltinType
+|-TypedefDecl '__NSConstantString'
+| `-RecordType
+|-CXXRecordDecl 'type_info'
+| `-TypeVisibilityAttr
+|-TypedefDecl 'size_t'
+| `-BuiltinType
+|-TypedefDecl '__builtin_ms_va_list'
+| `-PointerType
+|   `-BuiltinType
+|-TypedefDecl '__builtin_va_list'
+| `-PointerType
+|   `-BuiltinType
+`-VarDecl 'i'
+  `-IntegerLiteral
+)cpp");
+#else
+    EXPECT_EQ(dumpASTString(TK_AsIs, TUDecl),
+              R"cpp(
+TranslationUnitDecl
+|-TypedefDecl '__int128_t'
+| `-BuiltinType
+|-TypedefDecl '__uint128_t'
+| `-BuiltinType
+|-TypedefDecl '__NSConstantString'
+| `-RecordType
+|-TypedefDecl '__builtin_ms_va_list'
+| `-PointerType
+|   `-BuiltinType
+|-TypedefDecl '__builtin_va_list'
+| `-ConstantArrayType
+|   `-RecordType
+`-VarDecl 'i'
+  `-IntegerLiteral
+)cpp");
+#endif
+
+    EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource, TUDecl),
+              R"cpp(
+TranslationUnitDecl
+`-VarDecl 'i'
+  `-IntegerLiteral
+)cpp");
+  }
+
+  auto AST2 = buildASTFromCodeWithArgs(R"cpp(
+struct Simple {
+};
+struct Other {
+};
+
+struct Record : Simple, Other {
+  Record() : Simple(), m_i(42) {}
+private:
+  int m_i;
+  int m_i2 = 42;
+  Simple m_s;
+};
+
+struct NonTrivial {
+    NonTrivial() {}
+    NonTrivial(NonTrivial&) {}
+    NonTrivial& operator=(NonTrivial&) { return *this; }
+
+    ~NonTrivial() {}
+};
+
+struct ContainsArray {
+    NonTrivial arr[2];
+    int irr[2];
+    ContainsArray& operator=(ContainsArray &) = default;
+};
+
+void copyIt()
+{
+    ContainsArray ca;
+    ContainsArray ca2;
+    ca2 = ca;
+}
+
+void forLoop()
+{
+    int arr[2];
+    for (auto i : arr)
+    {
+
+    }
+    for (auto& a = arr; auto i : a)
+    {
+
+    }
+}
+
+struct DefaultedAndDeleted {
+  NonTrivial nt;
+  DefaultedAndDeleted() = default;
+  ~DefaultedAndDeleted() = default;
+  DefaultedAndDeleted(DefaultedAndDeleted &) = default;
+  DefaultedAndDeleted& operator=(DefaultedAndDeleted &) = default;
+  DefaultedAndDeleted(DefaultedAndDeleted &&) = delete;
+  DefaultedAndDeleted& operator=(DefaultedAndDeleted &&) = delete;
+};
+
+void copyIt2()
+{
+    DefaultedAndDeleted ca;
+    DefaultedAndDeleted ca2;
+    ca2 = ca;
+}
+
+void hasDefaultArg(int i, int j = 0)
+{
+}
+void callDefaultArg()
+{
+  hasDefaultArg(42);
+}
+)cpp",
+                                       {"-std=c++20"});
+
+  {
+    auto BN = ast_matchers::match(
+        cxxRecordDecl(hasName("Record"), unless(isImplicit())).bind("rec"),
+        AST2->getASTContext());
+    EXPECT_EQ(BN.size(), 1u);
+
+    EXPECT_EQ(dumpASTString(TK_AsIs, BN[0].getNodeAs<Decl>("rec")),
+              R"cpp(
+CXXRecordDecl 'Record'
+|-CXXRecordDecl 'Record'
+|-CXXConstructorDecl 'Record'
+| |-CXXCtorInitializer 'struct Simple'
+| | `-CXXConstructExpr
+| |-CXXCtorInitializer 'struct Other'
+| | `-CXXConstructExpr
+| |-CXXCtorInitializer 'm_i'
+| | `-IntegerLiteral
+| |-CXXCtorInitializer 'm_i2'
+| | `-CXXDefaultInitExpr
+| |-CXXCtorInitializer 'm_s'
+| | `-CXXConstructExpr
+| `-CompoundStmt
+|-AccessSpecDecl
+|-FieldDecl 'm_i'
+|-FieldDecl 'm_i2'
+| `-IntegerLiteral
+`-FieldDecl 'm_s'
+)cpp");
+
+    EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource,
+                            BN[0].getNodeAs<Decl>("rec")),
+              R"cpp(
+CXXRecordDecl 'Record'
+|-CXXConstructorDecl 'Record'
+| |-CXXCtorInitializer 'struct Simple'
+| | `-CXXConstructExpr
+| |-CXXCtorInitializer 'm_i'
+| | `-IntegerLiteral
+| `-CompoundStmt
+|-AccessSpecDecl
+|-FieldDecl 'm_i'
+|-FieldDecl 'm_i2'
+| `-IntegerLiteral
+`-FieldDecl 'm_s'
+)cpp");
+  }
+  {
+    auto BN = ast_matchers::match(
+        cxxRecordDecl(hasName("ContainsArray"), unless(isImplicit()))
+            .bind("rec"),
+        AST2->getASTContext());
+    EXPECT_EQ(BN.size(), 1u);
+
+    EXPECT_EQ(dumpASTString(TK_AsIs, BN[0].getNodeAs<Decl>("rec")),
+              R"cpp(
+CXXRecordDecl 'ContainsArray'
+|-CXXRecordDecl 'ContainsArray'
+|-FieldDecl 'arr'
+|-FieldDecl 'irr'
+|-CXXMethodDecl 'operator='
+| |-ParmVarDecl ''
+| `-CompoundStmt
+|   |-ForStmt
+|   | |-DeclStmt
+|   | | `-VarDecl '__i0'
+|   | |   `-IntegerLiteral
+|   | |-<<<NULL>>>
+|   | |-BinaryOperator
+|   | | |-ImplicitCastExpr
+|   | | | `-DeclRefExpr '__i0'
+|   | | `-IntegerLiteral
+|   | |-UnaryOperator
+|   | | `-DeclRefExpr '__i0'
+|   | `-CXXMemberCallExpr
+|   |   |-MemberExpr
+|   |   | `-ArraySubscriptExpr
+|   |   |   |-ImplicitCastExpr
+|   |   |   | `-MemberExpr
+|   |   |   |   `-CXXThisExpr
+|   |   |   `-ImplicitCastExpr
+|   |   |     `-DeclRefExpr '__i0'
+|   |   `-ArraySubscriptExpr
+|   |     |-ImplicitCastExpr
+|   |     | `-MemberExpr
+|   |     |   `-DeclRefExpr ''
+|   |     `-ImplicitCastExpr
+|   |       `-DeclRefExpr '__i0'
+|   |-CallExpr
+|   | |-ImplicitCastExpr
+|   | | `-DeclRefExpr '__builtin_memcpy'
+|   | |-ImplicitCastExpr
+|   | | `-UnaryOperator
+|   | |   `-MemberExpr
+|   | |     `-CXXThisExpr
+|   | |-ImplicitCastExpr
+|   | | `-UnaryOperator
+|   | |   `-MemberExpr
+|   | |     `-DeclRefExpr ''
+|   | `-IntegerLiteral
+|   `-ReturnStmt
+|     `-UnaryOperator
+|       `-CXXThisExpr
+|-CXXConstructorDecl 'ContainsArray'
+| `-ParmVarDecl ''
+|-CXXDestructorDecl '~ContainsArray'
+| `-CompoundStmt
+`-CXXConstructorDecl 'ContainsArray'
+  |-CXXCtorInitializer 'arr'
+  | `-CXXConstructExpr
+  `-CompoundStmt
+)cpp");
+
+    EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource,
+                            BN[0].getNodeAs<Decl>("rec")),
+              R"cpp(
+CXXRecordDecl 'ContainsArray'
+|-FieldDecl 'arr'
+|-FieldDecl 'irr'
+`-CXXMethodDecl 'operator='
+  `-ParmVarDecl ''
+)cpp");
+  }
+  {
+    auto BN = ast_matchers::match(functionDecl(hasName("forLoop")).bind("func"),
+                                  AST2->getASTContext());
+    EXPECT_EQ(BN.size(), 1u);
+
+    EXPECT_EQ(dumpASTString(TK_AsIs, BN[0].getNodeAs<Decl>("func")),
+              R"cpp(
+FunctionDecl 'forLoop'
+`-CompoundStmt
+  |-DeclStmt
+  | `-VarDecl 'arr'
+  |-CXXForRangeStmt
+  | |-<<<NULL>>>
+  | |-DeclStmt
+  | | `-VarDecl '__range1'
+  | |   `-DeclRefExpr 'arr'
+  | |-DeclStmt
+  | | `-VarDecl '__begin1'
+  | |   `-ImplicitCastExpr
+  | |     `-DeclRefExpr '__range1'
+  | |-DeclStmt
+  | | `-VarDecl '__end1'
+  | |   `-BinaryOperator
+  | |     |-ImplicitCastExpr
+  | |     | `-DeclRefExpr '__range1'
+  | |     `-IntegerLiteral
+  | |-BinaryOperator
+  | | |-ImplicitCastExpr
+  | | | `-DeclRefExpr '__begin1'
+  | | `-ImplicitCastExpr
+  | |   `-DeclRefExpr '__end1'
+  | |-UnaryOperator
+  | | `-DeclRefExpr '__begin1'
+  | |-DeclStmt
+  | | `-VarDecl 'i'
+  | |   `-ImplicitCastExpr
+  | |     `-UnaryOperator
+  | |       `-ImplicitCastExpr
+  | |         `-DeclRefExpr '__begin1'
+  | `-CompoundStmt
+  `-CXXForRangeStmt
+    |-DeclStmt
+    | `-VarDecl 'a'
+    |   `-DeclRefExpr 'arr'
+    |-DeclStmt
+    | `-VarDecl '__range1'
+    |   `-DeclRefExpr 'a'
+    |-DeclStmt
+    | `-VarDecl '__begin1'
+    |   `-ImplicitCastExpr
+    |     `-DeclRefExpr '__range1'
+    |-DeclStmt
+    | `-VarDecl '__end1'
+    |   `-BinaryOperator
+    |     |-ImplicitCastExpr
+    |     | `-DeclRefExpr '__range1'
+    |     `-IntegerLiteral
+    |-BinaryOperator
+    | |-ImplicitCastExpr
+    | | `-DeclRefExpr '__begin1'
+    | `-ImplicitCastExpr
+    |   `-DeclRefExpr '__end1'
+    |-UnaryOperator
+    | `-DeclRefExpr '__begin1'
+    |-DeclStmt
+    | `-VarDecl 'i'
+    |   `-ImplicitCastExpr
+    |     `-UnaryOperator
+    |       `-ImplicitCastExpr
+    |         `-DeclRefExpr '__begin1'
+    `-CompoundStmt
+)cpp");
+
+    EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource,
+                            BN[0].getNodeAs<Decl>("func")),
+              R"cpp(
+FunctionDecl 'forLoop'
+`-CompoundStmt
+  |-DeclStmt
+  | `-VarDecl 'arr'
+  |-CXXForRangeStmt
+  | |-<<<NULL>>>
+  | |-VarDecl 'i'
+  | |-DeclRefExpr 'arr'
+  | `-CompoundStmt
+  `-CXXForRangeStmt
+    |-DeclStmt
+    | `-VarDecl 'a'
+    |   `-DeclRefExpr 'arr'
+    |-VarDecl 'i'
+    |-DeclRefExpr 'a'
+    `-CompoundStmt
+)cpp");
+  }
+  {
+    auto BN = ast_matchers::match(
+        cxxRecordDecl(hasName("DefaultedAndDeleted"), unless(isImplicit()))
+            .bind("rec"),
+        AST2->getASTContext());
+    EXPECT_EQ(BN.size(), 1u);
+
+    EXPECT_EQ(dumpASTString(TK_AsIs, BN[0].getNodeAs<Decl>("rec")),
+              R"cpp(
+CXXRecordDecl 'DefaultedAndDeleted'
+|-CXXRecordDecl 'DefaultedAndDeleted'
+|-FieldDecl 'nt'
+|-CXXConstructorDecl 'DefaultedAndDeleted'
+| |-CXXCtorInitializer 'nt'
+| | `-CXXConstructExpr
+| `-CompoundStmt
+|-CXXDestructorDecl '~DefaultedAndDeleted'
+| `-CompoundStmt
+|-CXXConstructorDecl 'DefaultedAndDeleted'
+| `-ParmVarDecl ''
+|-CXXMethodDecl 'operator='
+| |-ParmVarDecl ''
+| `-CompoundStmt
+|   |-CXXMemberCallExpr
+|   | |-MemberExpr
+|   | | `-MemberExpr
+|   | |   `-CXXThisExpr
+|   | `-MemberExpr
+|   |   `-DeclRefExpr ''
+|   `-ReturnStmt
+|     `-UnaryOperator
+|       `-CXXThisExpr
+|-CXXConstructorDecl 'DefaultedAndDeleted'
+| `-ParmVarDecl ''
+`-CXXMethodDecl 'operator='
+  `-ParmVarDecl ''
+)cpp");
+
+    EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource,
+                            BN[0].getNodeAs<Decl>("rec")),
+              R"cpp(
+CXXRecordDecl 'DefaultedAndDeleted'
+|-FieldDecl 'nt'
+|-CXXConstructorDecl 'DefaultedAndDeleted'
+|-CXXDestructorDecl '~DefaultedAndDeleted'
+|-CXXConstructorDecl 'DefaultedAndDeleted'
+| `-ParmVarDecl ''
+|-CXXMethodDecl 'operator='
+| `-ParmVarDecl ''
+|-CXXConstructorDecl 'DefaultedAndDeleted'
+| `-ParmVarDecl ''
+`-CXXMethodDecl 'operator='
+  `-ParmVarDecl ''
+)cpp");
+  }
+  {
+    auto BN = ast_matchers::match(
+        callExpr(callee(functionDecl(hasName("hasDefaultArg"))))
+            .bind("funcCall"),
+        AST2->getASTContext());
+    EXPECT_EQ(BN.size(), 1u);
+
+    EXPECT_EQ(dumpASTString(TK_AsIs, BN[0].getNodeAs<CallExpr>("funcCall")),
+              R"cpp(
+CallExpr
+|-ImplicitCastExpr
+| `-DeclRefExpr 'hasDefaultArg'
+|-IntegerLiteral
+`-CXXDefaultArgExpr
+)cpp");
+    EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource,
+                            BN[0].getNodeAs<CallExpr>("funcCall")),
+              R"cpp(
+CallExpr
+|-DeclRefExpr 'hasDefaultArg'
+`-IntegerLiteral
+)cpp");
+  }
+}
+
 TEST(Traverse, IgnoreUnlessSpelledInSourceTemplateInstantiations) {
 
   auto AST = buildASTFromCode(R"cpp(
 template<typename T>
 struct TemplStruct {
   TemplStruct() {}
   ~TemplStruct() {}
 
)cpp");
     EXPECT_EQ(BN.size(), 1u);
 
     EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource,
                             BN[0].getNodeAs<Decl>("rec")),
               R"cpp(
 ClassTemplateDecl 'TemplStruct'
 |-TemplateTypeParmDecl 'T'
 `-CXXRecordDecl 'TemplStruct'
-  |-CXXRecordDecl 'TemplStruct'
   |-CXXConstructorDecl 'TemplStruct<T>'
   | `-CompoundStmt
   |-CXXDestructorDecl '~TemplStruct<T>'
   | `-CompoundStmt
   |-AccessSpecDecl
   `-FieldDecl 'm_t'
 )cpp");
 

 )cpp");
 
     EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource,
                             BN[0].getNodeAs<Decl>("templSpec")),
               R"cpp(
 ClassTemplateSpecializationDecl 'TemplStruct'
 |-TemplateArgument type _Bool
 | `-BuiltinType
-|-CXXRecordDecl 'TemplStruct'
 |-CXXConstructorDecl 'TemplStruct'
 | `-CompoundStmt
 |-CXXDestructorDecl '~TemplStruct'
 | `-CompoundStmt
 |-CXXMethodDecl 'foo'
 | `-CompoundStmt
 |-AccessSpecDecl
 `-FieldDecl 'm_t'

clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp

auto M = classTemplateSpecializationDecl(
         hasTemplateArgument(0, templateArgument(refersToType(booleanType()))),
         has(cxxConstructorDecl(hasName("TemplStruct"))),
         has(cxxMethodDecl(hasName("boolSpecializationMethodOnly"))));
     EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
     EXPECT_TRUE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
   }
 }
 
+TEST(Traversal, traverseNoImplicit) {
+  StringRef Code = R"cpp(
+struct NonTrivial {
+    NonTrivial() {}
+    NonTrivial(const NonTrivial&) {}
+    NonTrivial& operator=(const NonTrivial&) { return *this; }
+
+    ~NonTrivial() {}
+};
+
+struct NoSpecialMethods {
+    NonTrivial nt;
+};
+
+struct ContainsArray {
+    NonTrivial arr[2];
+    ContainsArray& operator=(const ContainsArray &other) = default;
+};
+
+void copyIt()
+{
+    NoSpecialMethods nc1;
+    NoSpecialMethods nc2(nc1);
+    nc2 = nc1;
+
+    ContainsArray ca;
+    ContainsArray ca2;
+    ca2 = ca;
+}
+
+struct HasCtorInits : NoSpecialMethods, NonTrivial
+{
+  int m_i;
+  NonTrivial m_nt;
+  HasCtorInits() : NoSpecialMethods(), m_i(42) {}
+};
+
+)cpp";
+  {
+    auto M = cxxRecordDecl(hasName("NoSpecialMethods"),
+                           has(cxxRecordDecl(hasName("NoSpecialMethods"))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+
+    M = cxxRecordDecl(hasName("NoSpecialMethods"),
+                      has(cxxConstructorDecl(isCopyConstructor())));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+
+    M = cxxRecordDecl(hasName("NoSpecialMethods"),
+                      has(cxxMethodDecl(isCopyAssignmentOperator())));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+
+    M = cxxRecordDecl(hasName("NoSpecialMethods"),
+                      has(cxxConstructorDecl(isDefaultConstructor())));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+
+    M = cxxRecordDecl(hasName("NoSpecialMethods"), has(cxxDestructorDecl()));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    // Compiler generates a forStmt to copy the array
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, forStmt())));
+    EXPECT_FALSE(
+        matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, forStmt())));
+  }
+  {
+    // The defaulted method declaration can be matched, but not its
+    // definition, in IgnoreUnlessSpelledInSource mode
+    auto MDecl = cxxMethodDecl(ofClass(cxxRecordDecl(hasName("ContainsArray"))),
+                               isCopyAssignmentOperator(), isDefaulted());
+
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, MDecl)));
+    EXPECT_TRUE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, MDecl)));
+
+    auto MDef = cxxMethodDecl(MDecl, has(compoundStmt()));
+
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, MDef)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, MDef)));
+
+    // The parameter of the defaulted method can still be matched.
+    auto MParm =
+        cxxMethodDecl(MDecl, hasParameter(0, parmVarDecl(hasName("other"))));
+
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, MParm)));
+    EXPECT_TRUE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, MParm)));
+  }
+  {
+    auto M =
+        cxxConstructorDecl(hasName("HasCtorInits"),
+                           has(cxxCtorInitializer(forField(hasName("m_i")))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_TRUE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M =
+        cxxConstructorDecl(hasName("HasCtorInits"),
+                           has(cxxCtorInitializer(forField(hasName("m_nt")))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M = cxxConstructorDecl(
+        hasName("HasCtorInits"),
+        has(cxxCtorInitializer(withInitializer(cxxConstructExpr(hasDeclaration(
+            cxxConstructorDecl(hasName("NoSpecialMethods"))))))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_TRUE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M = cxxConstructorDecl(
+        hasName("HasCtorInits"),
+        has(cxxCtorInitializer(withInitializer(cxxConstructExpr(
+            hasDeclaration(cxxConstructorDecl(hasName("NonTrivial"))))))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M = cxxCtorInitializer(forField(hasName("m_nt")));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+
+  Code = R"cpp(
+  void rangeFor()
+  {
+    int arr[2];
+    for (auto i : arr)
+    {
+
+    }
+  }
+  )cpp";
+  {
+    auto M = cxxForRangeStmt(has(binaryOperator(hasOperatorName("!="))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M =
+        cxxForRangeStmt(hasDescendant(binaryOperator(hasOperatorName("+"))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M =
+        cxxForRangeStmt(hasDescendant(unaryOperator(hasOperatorName("++"))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M = cxxForRangeStmt(has(declStmt()));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M =
+        cxxForRangeStmt(hasLoopVariable(varDecl(hasName("i"))),
+                        hasRangeInit(declRefExpr(to(varDecl(hasName("arr"))))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_TRUE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M = cxxForRangeStmt(unless(hasInitStatement(stmt())));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_TRUE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M = cxxForRangeStmt(hasBody(stmt()));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_TRUE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+
+  Code = R"cpp(
+  void rangeFor()
+  {
+    int arr[2];
+    for (auto& a = arr; auto i : a)
+    {
+
+    }
+  }
+  )cpp";
+  {
+    auto M = cxxForRangeStmt(has(binaryOperator(hasOperatorName("!="))));
+    EXPECT_TRUE(
+        matchesConditionally(Code, traverse(TK_AsIs, M), true, {"-std=c++20"}));
+    EXPECT_FALSE(
+        matchesConditionally(Code, traverse(TK_IgnoreUnlessSpelledInSource, M),
+                             true, {"-std=c++20"}));
+  }
+  {
+    auto M =
+        cxxForRangeStmt(hasDescendant(binaryOperator(hasOperatorName("+"))));
+    EXPECT_TRUE(
+        matchesConditionally(Code, traverse(TK_AsIs, M), true, {"-std=c++20"}));
+    EXPECT_FALSE(
+        matchesConditionally(Code, traverse(TK_IgnoreUnlessSpelledInSource, M),
+                             true, {"-std=c++20"}));
+  }
+  {
+    auto M =
+        cxxForRangeStmt(hasDescendant(unaryOperator(hasOperatorName("++"))));
+    EXPECT_TRUE(
+        matchesConditionally(Code, traverse(TK_AsIs, M), true, {"-std=c++20"}));
+    EXPECT_FALSE(
+        matchesConditionally(Code, traverse(TK_IgnoreUnlessSpelledInSource, M),
+                             true, {"-std=c++20"}));
+  }
+  {
+    auto M = cxxForRangeStmt(has(declStmt()));
+    EXPECT_TRUE(
+        matchesConditionally(Code, traverse(TK_AsIs, M), true, {"-std=c++20"}));
+    EXPECT_FALSE(
+        matchesConditionally(Code, traverse(TK_IgnoreUnlessSpelledInSource, M),
+                             true, {"-std=c++20"}));
+  }
+  {
+    auto M = cxxForRangeStmt(
+        hasInitStatement(declStmt(hasSingleDecl(varDecl(
+            hasName("a"),
+            hasInitializer(declRefExpr(to(varDecl(hasName("arr"))))))))),
+        hasLoopVariable(varDecl(hasName("i"))),
+        hasRangeInit(declRefExpr(to(varDecl(hasName("a"))))));
+    EXPECT_TRUE(
+        matchesConditionally(Code, traverse(TK_AsIs, M), true, {"-std=c++20"}));
+    EXPECT_TRUE(
+        matchesConditionally(Code, traverse(TK_IgnoreUnlessSpelledInSource, M),
+                             true, {"-std=c++20"}));
+  }
+  Code = R"cpp(
+void hasDefaultArg(int i, int j = 0)
+{
+}
+void callDefaultArg()
+{
+  hasDefaultArg(42);
+}
+)cpp";
+  {
+    auto M = callExpr(has(integerLiteral(equals(42))));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_TRUE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+  {
+    auto M = callExpr(has(cxxDefaultArgExpr()));
+    EXPECT_TRUE(matches(Code, traverse(TK_AsIs, M)));
+    EXPECT_FALSE(matches(Code, traverse(TK_IgnoreUnlessSpelledInSource, M)));
+  }
+}
+
 template <typename MatcherT>
 bool matcherTemplateWithBinding(StringRef Code, const MatcherT &M) {
   return matchAndVerifyResultTrue(
       Code, M.bind("matchedStmt"),
       std::make_unique<VerifyIdIsBoundTo<ReturnStmt>>("matchedStmt", 1));
 }
 
 TEST(Traversal, traverseWithBinding) {

clang/unittests/Tooling/TransformerTest.cpp

protected:
   template <typename R>
   void testRule(R Rule, StringRef Input, StringRef Expected) {
     Transformers.push_back(
         std::make_unique<Transformer>(std::move(Rule), consumer()));
     Transformers.back()->registerMatchers(&MatchFinder);
     compareSnippets(Expected, rewrite(Input));
   }
 
+  template <typename R> void testRuleFailure(R Rule, StringRef Input) {
+    Transformers.push_back(
+        std::make_unique<Transformer>(std::move(Rule), consumer()));
+    Transformers.back()->registerMatchers(&MatchFinder);
+    ASSERT_FALSE(rewrite(Input)) << "Expected failure to rewrite code";
+  }
+
   // Transformers are referenced by MatchFinder.
   std::vector<std::unique_ptr<Transformer>> Transformers;
   clang::ast_matchers::MatchFinder MatchFinder;
   // Records whether any errors occurred in individual changes.
   int ErrorCount = 0;
   AtomicChanges Changes;
 
 private:
TEST_F(TransformerTest, ErrorOccurredMatchSkipped) {
   T.registerMatchers(&MatchFinder);
   // The rewrite process itself fails...
   EXPECT_FALSE(rewrite(Input));
   // ... and no changes or errors are produced in the process.
   EXPECT_THAT(Changes, IsEmpty());
   EXPECT_EQ(ErrorCount, 0);
 }
 
+TEST_F(TransformerTest, ImplicitNodes_ConstructorDecl) {
+
+  std::string OtherStructPrefix = R"cpp(
+struct Other {
+)cpp";
+  std::string OtherStructSuffix = "};";
+
+  std::string CopyableStructName = "struct Copyable";
+  std::string BrokenStructName = "struct explicit Copyable";
+
+  std::string CodeSuffix = R"cpp(
+{
+    Other m_i;
+    Copyable();
+};
+)cpp";
+
+  std::string CopyCtor = "Other(const Other&) = default;";
+  std::string ExplicitCopyCtor = "explicit Other(const Other&) = default;";
+  std::string BrokenExplicitCopyCtor =
+      "explicit explicit explicit Other(const Other&) = default;";
+
+  std::string RewriteInput = OtherStructPrefix + CopyCtor + OtherStructSuffix +
+                             CopyableStructName + CodeSuffix;
+  std::string ExpectedRewriteOutput = OtherStructPrefix + ExplicitCopyCtor +
+                                      OtherStructSuffix + CopyableStructName +
+                                      CodeSuffix;
+  std::string BrokenRewriteOutput = OtherStructPrefix + BrokenExplicitCopyCtor +
+                                    OtherStructSuffix + BrokenStructName +
+                                    CodeSuffix;
+
+  auto MatchedRecord =
+      cxxConstructorDecl(isCopyConstructor()).bind("copyConstructor");
+
+  auto RewriteRule =
+      changeTo(before(node("copyConstructor")), cat("explicit "));
+
+  testRule(makeRule(traverse(TK_IgnoreUnlessSpelledInSource, MatchedRecord),
+                    RewriteRule),
+           RewriteInput, ExpectedRewriteOutput);
+
+  testRule(makeRule(traverse(TK_AsIs, MatchedRecord), RewriteRule),
+           RewriteInput, BrokenRewriteOutput);
+}
+
+TEST_F(TransformerTest, ImplicitNodes_RangeFor) {
+
+  std::string CodePrefix = R"cpp(
+struct Container
+{
+    int* begin() const;
+    int* end() const;
+    int* cbegin() const;
+    int* cend() const;
+};
+
+void foo()
+{
+  const Container c;
+)cpp";
+
+  std::string BeginCallBefore = "  c.begin();";
+  std::string BeginCallAfter = "  c.cbegin();";
+
+  std::string ForLoop = "for (auto i : c)";
+  std::string BrokenForLoop = "for (auto i :.cbegin() c)";
+
+  std::string CodeSuffix = R"cpp(
+  {
+  }
+}
+)cpp";
+
+  std::string RewriteInput =
+      CodePrefix + BeginCallBefore + ForLoop + CodeSuffix;
+  std::string ExpectedRewriteOutput =
+      CodePrefix + BeginCallAfter + ForLoop + CodeSuffix;
+  std::string BrokenRewriteOutput =
+      CodePrefix + BeginCallAfter + BrokenForLoop + CodeSuffix;
+
+  auto MatchedRecord =
+      cxxMemberCallExpr(on(expr(hasType(qualType(isConstQualified(),
+                                                 hasDeclaration(cxxRecordDecl(
+                                                     hasName("Container"))))))
+                               .bind("callTarget")),
+                        callee(cxxMethodDecl(hasName("begin"))))
+          .bind("constBeginCall");
+
+  auto RewriteRule =
+      changeTo(node("constBeginCall"), cat(name("callTarget"), ".cbegin()"));
+
+  testRule(makeRule(traverse(TK_IgnoreUnlessSpelledInSource, MatchedRecord),
+                    RewriteRule),
+           RewriteInput, ExpectedRewriteOutput);
+
+  testRule(makeRule(traverse(TK_AsIs, MatchedRecord), RewriteRule),
+           RewriteInput, BrokenRewriteOutput);
+}
+
+TEST_F(TransformerTest, ImplicitNodes_ForStmt) {
+
+  std::string CodePrefix = R"cpp(
+struct NonTrivial {
+    NonTrivial() {}
+    NonTrivial(NonTrivial&) {}
+    NonTrivial& operator=(NonTrivial const&) { return *this; }
+
+    ~NonTrivial() {}
+};
+
+struct ContainsArray {
+    NonTrivial arr[2];
+    ContainsArray& operator=(ContainsArray const&) = default;
+};
+
+void testIt()
+{
+    ContainsArray ca1;
+    ContainsArray ca2;
+    ca2 = ca1;
+)cpp";
+
+  auto CodeSuffix = "}";
+
+  auto LoopBody = R"cpp(
+    {
+
+    }
+)cpp";
+
+  auto RawLoop = "for (auto i = 0; i != 5; ++i)";
+
+  auto RangeLoop = "for (auto i : boost::irange(5))";
+
+  // Expect to rewrite the raw loop to the ranged loop.
+  // This works in TK_IgnoreUnlessSpelledInSource mode, but TK_AsIs
+  // mode also matches the hidden for loop generated in the copy assignment
+  // operator of ContainsArray. Transformer then fails to transform the code at
+  // all.
+
+  auto RewriteInput =
+      CodePrefix + RawLoop + LoopBody + RawLoop + LoopBody + CodeSuffix;
+
+  auto RewriteOutput =
+      CodePrefix + RangeLoop + LoopBody + RangeLoop + LoopBody + CodeSuffix;
+  {
+    auto MatchedLoop = forStmt(
+        has(declStmt(
+            hasSingleDecl(varDecl(hasInitializer(integerLiteral(equals(0))))
+                              .bind("loopVar")))),
+        has(binaryOperator(hasOperatorName("!="),
+                           hasLHS(ignoringImplicit(declRefExpr(
+                               to(varDecl(equalsBoundNode("loopVar")))))),
+                           hasRHS(expr().bind("upperBoundExpr")))),
+        has(unaryOperator(hasOperatorName("++"),
+                          hasUnaryOperand(declRefExpr(
+                              to(varDecl(equalsBoundNode("loopVar"))))))
+                .bind("incrementOp")));
+
+    auto RewriteRule =
+        changeTo(transformer::enclose(node("loopVar"), node("incrementOp")),
+                 cat("auto ", name("loopVar"), " : boost::irange(",
+                     node("upperBoundExpr"), ")"));
+
+    testRule(makeRule(traverse(TK_IgnoreUnlessSpelledInSource, MatchedLoop),
+                      RewriteRule),
+             RewriteInput, RewriteOutput);
+
+    testRuleFailure(makeRule(traverse(TK_AsIs, MatchedLoop), RewriteRule),
+                    RewriteInput);
+  }
+}
+
 TEST_F(TransformerTest, TemplateInstantiation) {
 
   std::string NonTemplatesInput = R"cpp(
 struct S {
   int m_i;
 };
 )cpp";
   std::string NonTemplatesExpected = R"cpp(