diff --git a/clang/lib/ARCMigrate/ObjCMT.cpp b/clang/lib/ARCMigrate/ObjCMT.cpp
index c1bc7c762088f..9e23789732711 100644
--- a/clang/lib/ARCMigrate/ObjCMT.cpp
+++ b/clang/lib/ARCMigrate/ObjCMT.cpp
@@ -7,16 +7,16 @@
 //===----------------------------------------------------------------------===//
 
 #include "Transforms.h"
-#include "clang/Analysis/RetainSummaryManager.h"
 #include "clang/ARCMigrate/ARCMT.h"
 #include "clang/ARCMigrate/ARCMTActions.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Attr.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/AST/NSAPI.h"
 #include "clang/AST/ParentMap.h"
-#include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
+#include "clang/Analysis/RetainSummaryManager.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Edit/Commit.h"
 #include "clang/Edit/EditedSource.h"
@@ -309,67 +309,68 @@ namespace {
     return true;
   }
 
-class ObjCMigrator : public RecursiveASTVisitor<ObjCMigrator> {
-  ObjCMigrateASTConsumer &Consumer;
-  ParentMap &PMap;
-
-public:
-  ObjCMigrator(ObjCMigrateASTConsumer &consumer, ParentMap &PMap)
-    : Consumer(consumer), PMap(PMap) { }
-
-  bool shouldVisitTemplateInstantiations() const { return false; }
-  bool shouldWalkTypesOfTypeLocs() const { return false; }
+  class ObjCMigrator : public DynamicRecursiveASTVisitor {
+    ObjCMigrateASTConsumer &Consumer;
+    ParentMap &PMap;
 
-  bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
-    if (Consumer.ASTMigrateActions & FrontendOptions::ObjCMT_Literals) {
-      edit::Commit commit(*Consumer.Editor);
-      edit::rewriteToObjCLiteralSyntax(E, *Consumer.NSAPIObj, commit, &PMap);
-      Consumer.Editor->commit(commit);
+  public:
+    ObjCMigrator(ObjCMigrateASTConsumer &consumer, ParentMap &PMap)
+        : Consumer(consumer), PMap(PMap) {
+      ShouldVisitTemplateInstantiations = false;
+      ShouldWalkTypesOfTypeLocs = false;
     }
 
-    if (Consumer.ASTMigrateActions & FrontendOptions::ObjCMT_Subscripting) {
-      edit::Commit commit(*Consumer.Editor);
-      edit::rewriteToObjCSubscriptSyntax(E, *Consumer.NSAPIObj, commit);
-      Consumer.Editor->commit(commit);
-    }
+    bool VisitObjCMessageExpr(ObjCMessageExpr *E) override {
+      if (Consumer.ASTMigrateActions & FrontendOptions::ObjCMT_Literals) {
+        edit::Commit commit(*Consumer.Editor);
+        edit::rewriteToObjCLiteralSyntax(E, *Consumer.NSAPIObj, commit, &PMap);
+        Consumer.Editor->commit(commit);
+      }
 
-    if (Consumer.ASTMigrateActions & FrontendOptions::ObjCMT_PropertyDotSyntax) {
-      edit::Commit commit(*Consumer.Editor);
-      rewriteToPropertyDotSyntax(E, Consumer.PP, *Consumer.NSAPIObj,
-                                 commit, &PMap);
-      Consumer.Editor->commit(commit);
-    }
+      if (Consumer.ASTMigrateActions & FrontendOptions::ObjCMT_Subscripting) {
+        edit::Commit commit(*Consumer.Editor);
+        edit::rewriteToObjCSubscriptSyntax(E, *Consumer.NSAPIObj, commit);
+        Consumer.Editor->commit(commit);
+      }
 
-    return true;
-  }
+      if (Consumer.ASTMigrateActions &
+          FrontendOptions::ObjCMT_PropertyDotSyntax) {
+        edit::Commit commit(*Consumer.Editor);
+        rewriteToPropertyDotSyntax(E, Consumer.PP, *Consumer.NSAPIObj, commit,
+                                   &PMap);
+        Consumer.Editor->commit(commit);
+      }
 
-  bool TraverseObjCMessageExpr(ObjCMessageExpr *E) {
-    // Do depth first; we want to rewrite the subexpressions first so that if
-    // we have to move expressions we will move them already rewritten.
-    for (Stmt *SubStmt : E->children())
-      if (!TraverseStmt(SubStmt))
-        return false;
+      return true;
+    }
 
-    return WalkUpFromObjCMessageExpr(E);
-  }
-};
+    bool TraverseObjCMessageExpr(ObjCMessageExpr *E) override {
+      // Do depth first; we want to rewrite the subexpressions first so that if
+      // we have to move expressions we will move them already rewritten.
+      for (Stmt *SubStmt : E->children())
+        if (!TraverseStmt(SubStmt))
+          return false;
 
-class BodyMigrator : public RecursiveASTVisitor<BodyMigrator> {
-  ObjCMigrateASTConsumer &Consumer;
-  std::unique_ptr<ParentMap> PMap;
+      return WalkUpFromObjCMessageExpr(E);
+    }
+  };
 
-public:
-  BodyMigrator(ObjCMigrateASTConsumer &consumer) : Consumer(consumer) { }
+  class BodyMigrator : public DynamicRecursiveASTVisitor {
+    ObjCMigrateASTConsumer &Consumer;
+    std::unique_ptr<ParentMap> PMap;
 
-  bool shouldVisitTemplateInstantiations() const { return false; }
-  bool shouldWalkTypesOfTypeLocs() const { return false; }
+  public:
+    BodyMigrator(ObjCMigrateASTConsumer &consumer) : Consumer(consumer) {
+      ShouldVisitTemplateInstantiations = false;
+      ShouldWalkTypesOfTypeLocs = false;
+    }
 
-  bool TraverseStmt(Stmt *S) {
-    PMap.reset(new ParentMap(S));
-    ObjCMigrator(Consumer, *PMap).TraverseStmt(S);
-    return true;
-  }
-};
+    bool TraverseStmt(Stmt *S) override {
+      PMap.reset(new ParentMap(S));
+      ObjCMigrator(Consumer, *PMap).TraverseStmt(S);
+      return true;
+    }
+  };
 } // end anonymous namespace
 
 void ObjCMigrateASTConsumer::migrateDecl(Decl *D) {
@@ -1672,12 +1673,14 @@ void ObjCMigrateASTConsumer::migrateAddMethodAnnotation(
 }
 
 namespace {
-class SuperInitChecker : public RecursiveASTVisitor<SuperInitChecker> {
+class SuperInitChecker : public DynamicRecursiveASTVisitor {
 public:
-  bool shouldVisitTemplateInstantiations() const { return false; }
-  bool shouldWalkTypesOfTypeLocs() const { return false; }
+  SuperInitChecker() {
+    ShouldVisitTemplateInstantiations = false;
+    ShouldWalkTypesOfTypeLocs = false;
+  }
 
-  bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
+  bool VisitObjCMessageExpr(ObjCMessageExpr *E) override {
     if (E->getReceiverKind() == ObjCMessageExpr::SuperInstance) {
       if (E->getMethodFamily() == OMF_init)
         return false;
diff --git a/clang/lib/ARCMigrate/TransAPIUses.cpp b/clang/lib/ARCMigrate/TransAPIUses.cpp
index 8f5d4f4bde06c..7c397c609b3ab 100644
--- a/clang/lib/ARCMigrate/TransAPIUses.cpp
+++ b/clang/lib/ARCMigrate/TransAPIUses.cpp
@@ -16,9 +16,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/Sema/SemaDiagnostic.h"
 
 using namespace clang;
@@ -27,7 +28,7 @@ using namespace trans;
 
 namespace {
 
-class APIChecker : public RecursiveASTVisitor<APIChecker> {
+class APIChecker : public DynamicRecursiveASTVisitor {
   MigrationPass &Pass;
 
   Selector getReturnValueSel, setReturnValueSel;
@@ -51,7 +52,7 @@ class APIChecker : public RecursiveASTVisitor<APIChecker> {
     zoneSel = sels.getNullarySelector(&ids.get("zone"));
   }
 
-  bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
+  bool VisitObjCMessageExpr(ObjCMessageExpr *E) override {
     // NSInvocation.
     if (E->isInstanceMessage() &&
         E->getReceiverInterface() &&
diff --git a/clang/lib/ARCMigrate/TransARCAssign.cpp b/clang/lib/ARCMigrate/TransARCAssign.cpp
index d1d5b9e014b17..23d03e371dda8 100644
--- a/clang/lib/ARCMigrate/TransARCAssign.cpp
+++ b/clang/lib/ARCMigrate/TransARCAssign.cpp
@@ -20,9 +20,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/Sema/SemaDiagnostic.h"
 
 using namespace clang;
@@ -31,14 +32,14 @@ using namespace trans;
 
 namespace {
 
-class ARCAssignChecker : public RecursiveASTVisitor<ARCAssignChecker> {
+class ARCAssignChecker : public DynamicRecursiveASTVisitor {
   MigrationPass &Pass;
   llvm::DenseSet<VarDecl *> ModifiedVars;
 
 public:
   ARCAssignChecker(MigrationPass &pass) : Pass(pass) { }
 
-  bool VisitBinaryOperator(BinaryOperator *Exp) {
+  bool VisitBinaryOperator(BinaryOperator *Exp) override {
     if (Exp->getType()->isDependentType())
       return true;
 
diff --git a/clang/lib/ARCMigrate/TransAutoreleasePool.cpp b/clang/lib/ARCMigrate/TransAutoreleasePool.cpp
index 6d501228e712b..d64d5d16754a4 100644
--- a/clang/lib/ARCMigrate/TransAutoreleasePool.cpp
+++ b/clang/lib/ARCMigrate/TransAutoreleasePool.cpp
@@ -26,9 +26,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Sema/SemaDiagnostic.h"
 #include <map>
@@ -39,7 +40,7 @@ using namespace trans;
 
 namespace {
 
-class ReleaseCollector : public RecursiveASTVisitor<ReleaseCollector> {
+class ReleaseCollector : public DynamicRecursiveASTVisitor {
   Decl *Dcl;
   SmallVectorImpl<ObjCMessageExpr *> &Releases;
 
@@ -47,7 +48,7 @@ class ReleaseCollector : public RecursiveASTVisitor<ReleaseCollector> {
   ReleaseCollector(Decl *D, SmallVectorImpl<ObjCMessageExpr *> &releases)
     : Dcl(D), Releases(releases) { }
 
-  bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
+  bool VisitObjCMessageExpr(ObjCMessageExpr *E) override {
     if (!E->isInstanceMessage())
       return true;
     if (E->getMethodFamily() != OMF_release)
@@ -60,27 +61,32 @@ class ReleaseCollector : public RecursiveASTVisitor<ReleaseCollector> {
     return true;
   }
 };
-
 }
 
 namespace {
 
-class AutoreleasePoolRewriter
-                         : public RecursiveASTVisitor<AutoreleasePoolRewriter> {
+class AutoreleasePoolRewriter : public BodyTransform {
+  bool TraversingBody = false;
+
 public:
   AutoreleasePoolRewriter(MigrationPass &pass)
-    : Body(nullptr), Pass(pass) {
+      : BodyTransform(pass), Body(nullptr) {
     PoolII = &pass.Ctx.Idents.get("NSAutoreleasePool");
     DrainSel = pass.Ctx.Selectors.getNullarySelector(
                                                  &pass.Ctx.Idents.get("drain"));
   }
 
-  void transformBody(Stmt *body, Decl *ParentD) {
+  bool TraverseStmt(Stmt *body) override {
+    if (TraversingBody)
+      return BodyTransform::TraverseStmt(body);
+
+    llvm::SaveAndRestore Restore{TraversingBody, true};
     Body = body;
-    TraverseStmt(body);
+    BodyTransform::TraverseStmt(body);
+    return true;
   }
 
-  ~AutoreleasePoolRewriter() {
+  ~AutoreleasePoolRewriter() override {
     SmallVector<VarDecl *, 8> VarsToHandle;
 
     for (std::map<VarDecl *, PoolVarInfo>::iterator
@@ -160,7 +166,7 @@ class AutoreleasePoolRewriter
     }
   }
 
-  bool VisitCompoundStmt(CompoundStmt *S) {
+  bool VisitCompoundStmt(CompoundStmt *S) override {
     SmallVector<PoolScope, 4> Scopes;
 
     for (Stmt::child_iterator
@@ -245,7 +251,7 @@ class AutoreleasePoolRewriter
     }
   };
 
-  class NameReferenceChecker : public RecursiveASTVisitor<NameReferenceChecker>{
+  class NameReferenceChecker : public DynamicRecursiveASTVisitor {
     ASTContext &Ctx;
     SourceRange ScopeRange;
     SourceLocation &referenceLoc, &declarationLoc;
@@ -260,15 +266,15 @@ class AutoreleasePoolRewriter
                                (*scope.End)->getBeginLoc());
     }
 
-    bool VisitDeclRefExpr(DeclRefExpr *E) {
+    bool VisitDeclRefExpr(DeclRefExpr *E) override {
       return checkRef(E->getLocation(), E->getDecl()->getLocation());
     }
 
-    bool VisitTypedefTypeLoc(TypedefTypeLoc TL) {
+    bool VisitTypedefTypeLoc(TypedefTypeLoc TL) override {
       return checkRef(TL.getBeginLoc(), TL.getTypedefNameDecl()->getLocation());
     }
 
-    bool VisitTagTypeLoc(TagTypeLoc TL) {
+    bool VisitTagTypeLoc(TagTypeLoc TL) override {
       return checkRef(TL.getBeginLoc(), TL.getDecl()->getLocation());
     }
 
@@ -411,7 +417,6 @@ class AutoreleasePoolRewriter
   }
 
   Stmt *Body;
-  MigrationPass &Pass;
 
   IdentifierInfo *PoolII;
   Selector DrainSel;
@@ -430,6 +435,6 @@ class AutoreleasePoolRewriter
 } // anonymous namespace
 
 void trans::rewriteAutoreleasePool(MigrationPass &pass) {
-  BodyTransform<AutoreleasePoolRewriter> trans(pass);
+  AutoreleasePoolRewriter trans(pass);
   trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
 }
diff --git a/clang/lib/ARCMigrate/TransBlockObjCVariable.cpp b/clang/lib/ARCMigrate/TransBlockObjCVariable.cpp
index 1e4db33135b6a..9c8869ebc8908 100644
--- a/clang/lib/ARCMigrate/TransBlockObjCVariable.cpp
+++ b/clang/lib/ARCMigrate/TransBlockObjCVariable.cpp
@@ -24,10 +24,11 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Attr.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/Basic/SourceManager.h"
 
 using namespace clang;
@@ -36,18 +37,16 @@ using namespace trans;
 
 namespace {
 
-class RootBlockObjCVarRewriter :
-                          public RecursiveASTVisitor<RootBlockObjCVarRewriter> {
+class RootBlockObjCVarRewriter : public DynamicRecursiveASTVisitor {
   llvm::DenseSet<VarDecl *> &VarsToChange;
 
-  class BlockVarChecker : public RecursiveASTVisitor<BlockVarChecker> {
+  class BlockVarChecker : public DynamicRecursiveASTVisitor {
     VarDecl *Var;
 
-    typedef RecursiveASTVisitor<BlockVarChecker> base;
   public:
     BlockVarChecker(VarDecl *var) : Var(var) { }
 
-    bool TraverseImplicitCastExpr(ImplicitCastExpr *castE) {
+    bool TraverseImplicitCastExpr(ImplicitCastExpr *castE) override {
       if (DeclRefExpr *
             ref = dyn_cast<DeclRefExpr>(castE->getSubExpr())) {
         if (ref->getDecl() == Var) {
@@ -59,10 +58,10 @@ class RootBlockObjCVarRewriter :
         }
       }
 
-      return base::TraverseImplicitCastExpr(castE);
+      return DynamicRecursiveASTVisitor::TraverseImplicitCastExpr(castE);
     }
 
-    bool VisitDeclRefExpr(DeclRefExpr *E) {
+    bool VisitDeclRefExpr(DeclRefExpr *E) override {
       if (E->getDecl() == Var)
         return false; // The reference of the variable, and not just its value,
                       //  is needed.
@@ -74,7 +73,7 @@ class RootBlockObjCVarRewriter :
   RootBlockObjCVarRewriter(llvm::DenseSet<VarDecl *> &VarsToChange)
     : VarsToChange(VarsToChange) { }
 
-  bool VisitBlockDecl(BlockDecl *block) {
+  bool VisitBlockDecl(BlockDecl *block) override {
     SmallVector<VarDecl *, 4> BlockVars;
 
     for (const auto &I : block->captures()) {
@@ -108,14 +107,14 @@ class RootBlockObjCVarRewriter :
   }
 };
 
-class BlockObjCVarRewriter : public RecursiveASTVisitor<BlockObjCVarRewriter> {
+class BlockObjCVarRewriter : public DynamicRecursiveASTVisitor {
   llvm::DenseSet<VarDecl *> &VarsToChange;
 
 public:
   BlockObjCVarRewriter(llvm::DenseSet<VarDecl *> &VarsToChange)
     : VarsToChange(VarsToChange) { }
 
-  bool TraverseBlockDecl(BlockDecl *block) {
+  bool TraverseBlockDecl(BlockDecl *block) override {
     RootBlockObjCVarRewriter(VarsToChange).TraverseDecl(block);
     return true;
   }
diff --git a/clang/lib/ARCMigrate/TransEmptyStatementsAndDealloc.cpp b/clang/lib/ARCMigrate/TransEmptyStatementsAndDealloc.cpp
index e9c21b8106d7d..ecbee51437cb6 100644
--- a/clang/lib/ARCMigrate/TransEmptyStatementsAndDealloc.cpp
+++ b/clang/lib/ARCMigrate/TransEmptyStatementsAndDealloc.cpp
@@ -18,9 +18,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/AST/StmtVisitor.h"
 #include "clang/Basic/SourceManager.h"
 
@@ -143,14 +144,13 @@ class EmptyChecker : public StmtVisitor<EmptyChecker, bool> {
   }
 };
 
-class EmptyStatementsRemover :
-                            public RecursiveASTVisitor<EmptyStatementsRemover> {
+class EmptyStatementsRemover : public DynamicRecursiveASTVisitor {
   MigrationPass &Pass;
 
 public:
   EmptyStatementsRemover(MigrationPass &pass) : Pass(pass) { }
 
-  bool TraverseStmtExpr(StmtExpr *E) {
+  bool TraverseStmtExpr(StmtExpr *E) override {
     CompoundStmt *S = E->getSubStmt();
     for (CompoundStmt::body_iterator
            I = S->body_begin(), E = S->body_end(); I != E; ++I) {
@@ -161,7 +161,7 @@ class EmptyStatementsRemover :
     return true;
   }
 
-  bool VisitCompoundStmt(CompoundStmt *S) {
+  bool VisitCompoundStmt(CompoundStmt *S) override {
     for (auto *I : S->body())
       check(I);
     return true;
diff --git a/clang/lib/ARCMigrate/TransGCAttrs.cpp b/clang/lib/ARCMigrate/TransGCAttrs.cpp
index 85e3fe77660b5..1fbb5b896a0c2 100644
--- a/clang/lib/ARCMigrate/TransGCAttrs.cpp
+++ b/clang/lib/ARCMigrate/TransGCAttrs.cpp
@@ -6,9 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Sema/SemaDiagnostic.h"
@@ -23,26 +24,24 @@ using namespace trans;
 namespace {
 
 /// Collects all the places where GC attributes __strong/__weak occur.
-class GCAttrsCollector : public RecursiveASTVisitor<GCAttrsCollector> {
+class GCAttrsCollector : public DynamicRecursiveASTVisitor {
   MigrationContext &MigrateCtx;
   bool FullyMigratable;
   std::vector<ObjCPropertyDecl *> &AllProps;
 
-  typedef RecursiveASTVisitor<GCAttrsCollector> base;
 public:
   GCAttrsCollector(MigrationContext &ctx,
                    std::vector<ObjCPropertyDecl *> &AllProps)
-    : MigrateCtx(ctx), FullyMigratable(false),
-      AllProps(AllProps) { }
-
-  bool shouldWalkTypesOfTypeLocs() const { return false; }
+      : MigrateCtx(ctx), FullyMigratable(false), AllProps(AllProps) {
+    ShouldWalkTypesOfTypeLocs = false;
+  }
 
-  bool VisitAttributedTypeLoc(AttributedTypeLoc TL) {
+  bool VisitAttributedTypeLoc(AttributedTypeLoc TL) override {
     handleAttr(TL);
     return true;
   }
 
-  bool TraverseDecl(Decl *D) {
+  bool TraverseDecl(Decl *D) override {
     if (!D || D->isImplicit())
       return true;
 
@@ -54,7 +53,7 @@ class GCAttrsCollector : public RecursiveASTVisitor<GCAttrsCollector> {
     } else if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
       lookForAttribute(DD, DD->getTypeSourceInfo());
     }
-    return base::TraverseDecl(D);
+    return DynamicRecursiveASTVisitor::TraverseDecl(D);
   }
 
   void lookForAttribute(Decl *D, TypeSourceInfo *TInfo) {
diff --git a/clang/lib/ARCMigrate/TransGCCalls.cpp b/clang/lib/ARCMigrate/TransGCCalls.cpp
index 43233e2d0b456..c2717dd1a7251 100644
--- a/clang/lib/ARCMigrate/TransGCCalls.cpp
+++ b/clang/lib/ARCMigrate/TransGCCalls.cpp
@@ -6,9 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/Sema/SemaDiagnostic.h"
 
 using namespace clang;
@@ -17,8 +18,7 @@ using namespace trans;
 
 namespace {
 
-class GCCollectableCallsChecker :
-                         public RecursiveASTVisitor<GCCollectableCallsChecker> {
+class GCCollectableCallsChecker : public DynamicRecursiveASTVisitor {
   MigrationContext &MigrateCtx;
   IdentifierInfo *NSMakeCollectableII;
   IdentifierInfo *CFMakeCollectableII;
@@ -29,11 +29,10 @@ class GCCollectableCallsChecker :
     IdentifierTable &Ids = MigrateCtx.Pass.Ctx.Idents;
     NSMakeCollectableII = &Ids.get("NSMakeCollectable");
     CFMakeCollectableII = &Ids.get("CFMakeCollectable");
+    ShouldWalkTypesOfTypeLocs = false;
   }
 
-  bool shouldWalkTypesOfTypeLocs() const { return false; }
-
-  bool VisitCallExpr(CallExpr *E) {
+  bool VisitCallExpr(CallExpr *E) override {
     TransformActions &TA = MigrateCtx.Pass.TA;
 
     if (MigrateCtx.isGCOwnedNonObjC(E->getType())) {
diff --git a/clang/lib/ARCMigrate/TransProperties.cpp b/clang/lib/ARCMigrate/TransProperties.cpp
index 6d1d950821a07..ee62ae41dd5f0 100644
--- a/clang/lib/ARCMigrate/TransProperties.cpp
+++ b/clang/lib/ARCMigrate/TransProperties.cpp
@@ -29,8 +29,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Sema/SemaDiagnostic.h"
@@ -281,12 +282,12 @@ class PropertiesRewriter {
     return MigrateCtx.addPropertyAttribute(attr, atLoc);
   }
 
-  class PlusOneAssign : public RecursiveASTVisitor<PlusOneAssign> {
+  class PlusOneAssign : public DynamicRecursiveASTVisitor {
     ObjCIvarDecl *Ivar;
   public:
     PlusOneAssign(ObjCIvarDecl *D) : Ivar(D) {}
 
-    bool VisitBinaryOperator(BinaryOperator *E) {
+    bool VisitBinaryOperator(BinaryOperator *E) override {
       if (E->getOpcode() != BO_Assign)
         return true;
 
diff --git a/clang/lib/ARCMigrate/TransProtectedScope.cpp b/clang/lib/ARCMigrate/TransProtectedScope.cpp
index 154e0b54800f9..a861ab29b1b9b 100644
--- a/clang/lib/ARCMigrate/TransProtectedScope.cpp
+++ b/clang/lib/ARCMigrate/TransProtectedScope.cpp
@@ -14,6 +14,7 @@
 #include "Internals.h"
 #include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Sema/SemaDiagnostic.h"
 
@@ -23,14 +24,14 @@ using namespace trans;
 
 namespace {
 
-class LocalRefsCollector : public RecursiveASTVisitor<LocalRefsCollector> {
+class LocalRefsCollector : public DynamicRecursiveASTVisitor {
   SmallVectorImpl<DeclRefExpr *> &Refs;
 
 public:
   LocalRefsCollector(SmallVectorImpl<DeclRefExpr *> &refs)
     : Refs(refs) { }
 
-  bool VisitDeclRefExpr(DeclRefExpr *E) {
+  bool VisitDeclRefExpr(DeclRefExpr *E) override {
     if (ValueDecl *D = E->getDecl())
       if (D->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
         Refs.push_back(E);
@@ -52,7 +53,7 @@ struct CaseInfo {
     : SC(S), Range(Range), State(St_Unchecked) {}
 };
 
-class CaseCollector : public RecursiveASTVisitor<CaseCollector> {
+class CaseCollector : public DynamicRecursiveASTVisitor {
   ParentMap &PMap;
   SmallVectorImpl<CaseInfo> &Cases;
 
@@ -60,7 +61,7 @@ class CaseCollector : public RecursiveASTVisitor<CaseCollector> {
   CaseCollector(ParentMap &PMap, SmallVectorImpl<CaseInfo> &Cases)
     : PMap(PMap), Cases(Cases) { }
 
-  bool VisitSwitchStmt(SwitchStmt *S) {
+  bool VisitSwitchStmt(SwitchStmt *S) override {
     SwitchCase *Curr = S->getSwitchCaseList();
     if (!Curr)
       return true;
diff --git a/clang/lib/ARCMigrate/TransRetainReleaseDealloc.cpp b/clang/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
index baa503d8a39dc..6e10dcc856974 100644
--- a/clang/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
+++ b/clang/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
@@ -16,9 +16,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/AST/ParentMap.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Lex/Lexer.h"
@@ -31,33 +32,37 @@ using namespace trans;
 
 namespace {
 
-class RetainReleaseDeallocRemover :
-                       public RecursiveASTVisitor<RetainReleaseDeallocRemover> {
+class RetainReleaseDeallocRemover : public BodyTransform {
   Stmt *Body;
-  MigrationPass &Pass;
 
   ExprSet Removables;
   std::unique_ptr<ParentMap> StmtMap;
+  bool TraversingBody = false;
 
   Selector DelegateSel, FinalizeSel;
 
 public:
   RetainReleaseDeallocRemover(MigrationPass &pass)
-    : Body(nullptr), Pass(pass) {
+      : BodyTransform(pass), Body(nullptr) {
     DelegateSel =
         Pass.Ctx.Selectors.getNullarySelector(&Pass.Ctx.Idents.get("delegate"));
     FinalizeSel =
         Pass.Ctx.Selectors.getNullarySelector(&Pass.Ctx.Idents.get("finalize"));
   }
 
-  void transformBody(Stmt *body, Decl *ParentD) {
+  bool TraverseStmt(Stmt *body) override {
+    if (TraversingBody)
+      return BodyTransform::TraverseStmt(body);
+
+    llvm::SaveAndRestore Restore{TraversingBody, true};
     Body = body;
     collectRemovables(body, Removables);
     StmtMap.reset(new ParentMap(body));
-    TraverseStmt(body);
+    BodyTransform::TraverseStmt(body);
+    return true;
   }
 
-  bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
+  bool VisitObjCMessageExpr(ObjCMessageExpr *E) override {
     switch (E->getMethodFamily()) {
     default:
       if (E->isInstanceMessage() && E->getSelector() == FinalizeSel)
@@ -448,12 +453,11 @@ class RetainReleaseDeallocRemover :
 
     return false;
   }
-
 };
 
 } // anonymous namespace
 
 void trans::removeRetainReleaseDeallocFinalize(MigrationPass &pass) {
-  BodyTransform<RetainReleaseDeallocRemover> trans(pass);
+  RetainReleaseDeallocRemover trans(pass);
   trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
 }
diff --git a/clang/lib/ARCMigrate/TransUnbridgedCasts.cpp b/clang/lib/ARCMigrate/TransUnbridgedCasts.cpp
index 7390ea17c8a4b..ef701c3d7358d 100644
--- a/clang/lib/ARCMigrate/TransUnbridgedCasts.cpp
+++ b/clang/lib/ARCMigrate/TransUnbridgedCasts.cpp
@@ -39,11 +39,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Attr.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/AST/ParentMap.h"
+#include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Lex/Lexer.h"
@@ -55,8 +57,35 @@ using namespace arcmt;
 using namespace trans;
 
 namespace {
+// FIXME: UnbridgedCastRewriter should probably just inherit from
+// BodyTransform (and this class shouldn't exist in the first place),
+// but I have so far been unable to untangle whatever is actually going
+// on in TraverseBlockDecl() that makes that not work properly...
+template <typename BODY_TRANS>
+class UnbridgedCastRewriterWrapper
+    : public RecursiveASTVisitor<UnbridgedCastRewriterWrapper<BODY_TRANS>> {
+  MigrationPass &Pass;
+  Decl *ParentD;
+
+  typedef RecursiveASTVisitor<UnbridgedCastRewriterWrapper<BODY_TRANS>> base;
+
+public:
+  UnbridgedCastRewriterWrapper(MigrationPass &pass)
+      : Pass(pass), ParentD(nullptr) {}
+
+  bool TraverseStmt(Stmt *rootS) {
+    if (rootS)
+      BODY_TRANS(Pass).transformBody(rootS, ParentD);
+    return true;
+  }
+
+  bool TraverseObjCMethodDecl(ObjCMethodDecl *D) {
+    SaveAndRestore<Decl *> SetParent(ParentD, D);
+    return base::TraverseObjCMethodDecl(D);
+  }
+};
 
-class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
+class UnbridgedCastRewriter : public DynamicRecursiveASTVisitor {
   MigrationPass &Pass;
   IdentifierInfo *SelfII;
   std::unique_ptr<ParentMap> StmtMap;
@@ -77,14 +106,14 @@ class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
     TraverseStmt(body);
   }
 
-  bool TraverseBlockDecl(BlockDecl *D) {
+  bool TraverseBlockDecl(BlockDecl *D) override {
     // ParentMap does not enter into a BlockDecl to record its stmts, so use a
     // new UnbridgedCastRewriter to handle the block.
     UnbridgedCastRewriter(Pass).transformBody(D->getBody(), D);
     return true;
   }
 
-  bool VisitCastExpr(CastExpr *E) {
+  bool VisitCastExpr(CastExpr *E) override {
     if (E->getCastKind() != CK_CPointerToObjCPointerCast &&
         E->getCastKind() != CK_BitCast &&
         E->getCastKind() != CK_AnyPointerToBlockPointerCast)
@@ -461,6 +490,6 @@ class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
 } // end anonymous namespace
 
 void trans::rewriteUnbridgedCasts(MigrationPass &pass) {
-  BodyTransform<UnbridgedCastRewriter> trans(pass);
+  UnbridgedCastRewriterWrapper<UnbridgedCastRewriter> trans(pass);
   trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
 }
diff --git a/clang/lib/ARCMigrate/TransUnusedInitDelegate.cpp b/clang/lib/ARCMigrate/TransUnusedInitDelegate.cpp
index bac8dfac9b415..98e54227116c2 100644
--- a/clang/lib/ARCMigrate/TransUnusedInitDelegate.cpp
+++ b/clang/lib/ARCMigrate/TransUnusedInitDelegate.cpp
@@ -19,9 +19,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/Sema/SemaDiagnostic.h"
 
 using namespace clang;
@@ -30,23 +31,27 @@ using namespace trans;
 
 namespace {
 
-class UnusedInitRewriter : public RecursiveASTVisitor<UnusedInitRewriter> {
+class UnusedInitRewriter : public BodyTransform {
   Stmt *Body;
-  MigrationPass &Pass;
-
   ExprSet Removables;
+  bool TraversingBody = false;
 
 public:
   UnusedInitRewriter(MigrationPass &pass)
-    : Body(nullptr), Pass(pass) { }
+      : BodyTransform(pass), Body(nullptr) {}
 
-  void transformBody(Stmt *body, Decl *ParentD) {
+  bool TraverseStmt(Stmt *body) override {
+    if (TraversingBody)
+      return BodyTransform::TraverseStmt(body);
+
+    llvm::SaveAndRestore Restore{TraversingBody, true};
     Body = body;
     collectRemovables(body, Removables);
-    TraverseStmt(body);
+    BodyTransform::TraverseStmt(body);
+    return true;
   }
 
-  bool VisitObjCMessageExpr(ObjCMessageExpr *ME) {
+  bool VisitObjCMessageExpr(ObjCMessageExpr *ME) override {
     if (ME->isDelegateInitCall() &&
         isRemovable(ME) &&
         Pass.TA.hasDiagnostic(diag::err_arc_unused_init_message,
@@ -72,6 +77,6 @@ class UnusedInitRewriter : public RecursiveASTVisitor<UnusedInitRewriter> {
 } // anonymous namespace
 
 void trans::rewriteUnusedInitDelegate(MigrationPass &pass) {
-  BodyTransform<UnusedInitRewriter> trans(pass);
+  UnusedInitRewriter trans(pass);
   trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
 }
diff --git a/clang/lib/ARCMigrate/TransZeroOutPropsInDealloc.cpp b/clang/lib/ARCMigrate/TransZeroOutPropsInDealloc.cpp
index 81e67628fb1f4..4aeb305a08eb2 100644
--- a/clang/lib/ARCMigrate/TransZeroOutPropsInDealloc.cpp
+++ b/clang/lib/ARCMigrate/TransZeroOutPropsInDealloc.cpp
@@ -12,9 +12,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Transforms.h"
 #include "Internals.h"
+#include "Transforms.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 
 using namespace clang;
 using namespace arcmt;
@@ -22,10 +23,7 @@ using namespace trans;
 
 namespace {
 
-class ZeroOutInDeallocRemover :
-                           public RecursiveASTVisitor<ZeroOutInDeallocRemover> {
-  typedef RecursiveASTVisitor<ZeroOutInDeallocRemover> base;
-
+class ZeroOutInDeallocRemover : public DynamicRecursiveASTVisitor {
   MigrationPass &Pass;
 
   llvm::DenseMap<ObjCPropertyDecl*, ObjCPropertyImplDecl*> SynthesizedProperties;
@@ -39,7 +37,7 @@ class ZeroOutInDeallocRemover :
         Pass.Ctx.Selectors.getNullarySelector(&Pass.Ctx.Idents.get("finalize"));
   }
 
-  bool VisitObjCMessageExpr(ObjCMessageExpr *ME) {
+  bool VisitObjCMessageExpr(ObjCMessageExpr *ME) override {
     ASTContext &Ctx = Pass.Ctx;
     TransformActions &TA = Pass.TA;
 
@@ -78,7 +76,7 @@ class ZeroOutInDeallocRemover :
     return true;
   }
 
-  bool VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
+  bool VisitPseudoObjectExpr(PseudoObjectExpr *POE) override {
     if (isZeroingPropIvar(POE) && isRemovable(POE)) {
       Transaction Trans(Pass.TA);
       Pass.TA.removeStmt(POE);
@@ -87,7 +85,7 @@ class ZeroOutInDeallocRemover :
     return true;
   }
 
-  bool VisitBinaryOperator(BinaryOperator *BOE) {
+  bool VisitBinaryOperator(BinaryOperator *BOE) override {
     if (isZeroingPropIvar(BOE) && isRemovable(BOE)) {
       Transaction Trans(Pass.TA);
       Pass.TA.removeStmt(BOE);
@@ -96,7 +94,7 @@ class ZeroOutInDeallocRemover :
     return true;
   }
 
-  bool TraverseObjCMethodDecl(ObjCMethodDecl *D) {
+  bool TraverseObjCMethodDecl(ObjCMethodDecl *D) override {
     if (D->getMethodFamily() != OMF_dealloc &&
         !(D->isInstanceMethod() && D->getSelector() == FinalizeSel))
       return true;
@@ -128,7 +126,7 @@ class ZeroOutInDeallocRemover :
     }
 
     // Now, remove all zeroing of ivars etc.
-    base::TraverseObjCMethodDecl(D);
+    DynamicRecursiveASTVisitor::TraverseObjCMethodDecl(D);
 
     // clear out for next method.
     SynthesizedProperties.clear();
@@ -137,9 +135,9 @@ class ZeroOutInDeallocRemover :
     return true;
   }
 
-  bool TraverseFunctionDecl(FunctionDecl *D) { return true; }
-  bool TraverseBlockDecl(BlockDecl *block) { return true; }
-  bool TraverseBlockExpr(BlockExpr *block) { return true; }
+  bool TraverseFunctionDecl(FunctionDecl *D) override { return true; }
+  bool TraverseBlockDecl(BlockDecl *block) override { return true; }
+  bool TraverseBlockExpr(BlockExpr *block) override { return true; }
 
 private:
   bool isRemovable(Expr *E) const {
diff --git a/clang/lib/ARCMigrate/Transforms.cpp b/clang/lib/ARCMigrate/Transforms.cpp
index fda0e1c932fc0..ce08be82bcf03 100644
--- a/clang/lib/ARCMigrate/Transforms.cpp
+++ b/clang/lib/ARCMigrate/Transforms.cpp
@@ -10,6 +10,7 @@
 #include "Internals.h"
 #include "clang/ARCMigrate/ARCMT.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
 #include "clang/Basic/SourceManager.h"
@@ -211,14 +212,17 @@ StringRef trans::getNilString(MigrationPass &Pass) {
 
 namespace {
 
-class ReferenceClear : public RecursiveASTVisitor<ReferenceClear> {
+class ReferenceClear : public DynamicRecursiveASTVisitor {
   ExprSet &Refs;
 public:
   ReferenceClear(ExprSet &refs) : Refs(refs) { }
-  bool VisitDeclRefExpr(DeclRefExpr *E) { Refs.erase(E); return true; }
+  bool VisitDeclRefExpr(DeclRefExpr *E) override {
+    Refs.erase(E);
+    return true;
+  }
 };
 
-class ReferenceCollector : public RecursiveASTVisitor<ReferenceCollector> {
+class ReferenceCollector : public DynamicRecursiveASTVisitor {
   ValueDecl *Dcl;
   ExprSet &Refs;
 
@@ -226,23 +230,22 @@ class ReferenceCollector : public RecursiveASTVisitor<ReferenceCollector> {
   ReferenceCollector(ValueDecl *D, ExprSet &refs)
     : Dcl(D), Refs(refs) { }
 
-  bool VisitDeclRefExpr(DeclRefExpr *E) {
+  bool VisitDeclRefExpr(DeclRefExpr *E) override {
     if (E->getDecl() == Dcl)
       Refs.insert(E);
     return true;
   }
 };
 
-class RemovablesCollector : public RecursiveASTVisitor<RemovablesCollector> {
+class RemovablesCollector : public DynamicRecursiveASTVisitor {
   ExprSet &Removables;
 
 public:
-  RemovablesCollector(ExprSet &removables)
-  : Removables(removables) { }
-
-  bool shouldWalkTypesOfTypeLocs() const { return false; }
+  RemovablesCollector(ExprSet &removables) : Removables(removables) {
+    ShouldWalkTypesOfTypeLocs = false;
+  }
 
-  bool TraverseStmtExpr(StmtExpr *E) {
+  bool TraverseStmtExpr(StmtExpr *E) override {
     CompoundStmt *S = E->getSubStmt();
     for (CompoundStmt::body_iterator
         I = S->body_begin(), E = S->body_end(); I != E; ++I) {
@@ -253,29 +256,29 @@ class RemovablesCollector : public RecursiveASTVisitor<RemovablesCollector> {
     return true;
   }
 
-  bool VisitCompoundStmt(CompoundStmt *S) {
+  bool VisitCompoundStmt(CompoundStmt *S) override {
     for (auto *I : S->body())
       mark(I);
     return true;
   }
 
-  bool VisitIfStmt(IfStmt *S) {
+  bool VisitIfStmt(IfStmt *S) override {
     mark(S->getThen());
     mark(S->getElse());
     return true;
   }
 
-  bool VisitWhileStmt(WhileStmt *S) {
+  bool VisitWhileStmt(WhileStmt *S) override {
     mark(S->getBody());
     return true;
   }
 
-  bool VisitDoStmt(DoStmt *S) {
+  bool VisitDoStmt(DoStmt *S) override {
     mark(S->getBody());
     return true;
   }
 
-  bool VisitForStmt(ForStmt *S) {
+  bool VisitForStmt(ForStmt *S) override {
     mark(S->getInit());
     mark(S->getInc());
     mark(S->getBody());
@@ -315,26 +318,25 @@ void trans::collectRemovables(Stmt *S, ExprSet &exprs) {
 
 namespace {
 
-class ASTTransform : public RecursiveASTVisitor<ASTTransform> {
+class ASTTransform : public DynamicRecursiveASTVisitor {
   MigrationContext &MigrateCtx;
-  typedef RecursiveASTVisitor<ASTTransform> base;
 
 public:
-  ASTTransform(MigrationContext &MigrateCtx) : MigrateCtx(MigrateCtx) { }
-
-  bool shouldWalkTypesOfTypeLocs() const { return false; }
+  ASTTransform(MigrationContext &MigrateCtx) : MigrateCtx(MigrateCtx) {
+    ShouldWalkTypesOfTypeLocs = false;
+  }
 
-  bool TraverseObjCImplementationDecl(ObjCImplementationDecl *D) {
+  bool TraverseObjCImplementationDecl(ObjCImplementationDecl *D) override {
     ObjCImplementationContext ImplCtx(MigrateCtx, D);
     for (MigrationContext::traverser_iterator
            I = MigrateCtx.traversers_begin(),
            E = MigrateCtx.traversers_end(); I != E; ++I)
       (*I)->traverseObjCImplementation(ImplCtx);
 
-    return base::TraverseObjCImplementationDecl(D);
+    return DynamicRecursiveASTVisitor::TraverseObjCImplementationDecl(D);
   }
 
-  bool TraverseStmt(Stmt *rootS) {
+  bool TraverseStmt(Stmt *rootS) override {
     if (!rootS)
       return true;
 
@@ -347,7 +349,6 @@ class ASTTransform : public RecursiveASTVisitor<ASTTransform> {
     return true;
   }
 };
-
 }
 
 MigrationContext::~MigrationContext() {
diff --git a/clang/lib/ARCMigrate/Transforms.h b/clang/lib/ARCMigrate/Transforms.h
index 37e2d6b2a7e12..0bb3172e506d1 100644
--- a/clang/lib/ARCMigrate/Transforms.h
+++ b/clang/lib/ARCMigrate/Transforms.h
@@ -9,8 +9,11 @@
 #ifndef LLVM_CLANG_LIB_ARCMIGRATE_TRANSFORMS_H
 #define LLVM_CLANG_LIB_ARCMIGRATE_TRANSFORMS_H
 
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/DynamicRecursiveASTVisitor.h"
+#include "clang/AST/ExprObjC.h"
 #include "clang/AST/ParentMap.h"
-#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/AST/StmtObjC.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/Support/SaveAndRestore.h"
 
@@ -181,24 +184,17 @@ bool isGlobalVar(Expr *E);
 /// Returns "nil" or "0" if 'nil' macro is not actually defined.
 StringRef getNilString(MigrationPass &Pass);
 
-template <typename BODY_TRANS>
-class BodyTransform : public RecursiveASTVisitor<BodyTransform<BODY_TRANS> > {
+class BodyTransform : public DynamicRecursiveASTVisitor {
+protected:
   MigrationPass &Pass;
   Decl *ParentD;
 
-  typedef RecursiveASTVisitor<BodyTransform<BODY_TRANS> > base;
 public:
-  BodyTransform(MigrationPass &pass) : Pass(pass), ParentD(nullptr) { }
+  BodyTransform(MigrationPass &pass) : Pass(pass), ParentD(nullptr) {}
 
-  bool TraverseStmt(Stmt *rootS) {
-    if (rootS)
-      BODY_TRANS(Pass).transformBody(rootS, ParentD);
-    return true;
-  }
-
-  bool TraverseObjCMethodDecl(ObjCMethodDecl *D) {
+  bool TraverseObjCMethodDecl(ObjCMethodDecl *D) override {
     SaveAndRestore<Decl *> SetParent(ParentD, D);
-    return base::TraverseObjCMethodDecl(D);
+    return DynamicRecursiveASTVisitor::TraverseObjCMethodDecl(D);
   }
 };