diff --git a/src/google/protobuf/compiler/cpp/message.cc b/src/google/protobuf/compiler/cpp/message.cc
index 8af17c8abf..3ac44ad13c 100644
--- a/src/google/protobuf/compiler/cpp/message.cc
+++ b/src/google/protobuf/compiler/cpp/message.cc
@@ -1642,7 +1642,7 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* p) {
         "int GetCachedSize() const final { return "
         "$cached_size$.Get(); }"
         "\n\nprivate:\n"
-        "void SharedCtor(::$proto_ns$::Arena* arena, bool is_message_owned);\n"
+        "void SharedCtor(::$proto_ns$::Arena* arena);\n"
         "void SharedDtor();\n"
         "void SetCachedSize(int size) const$ full_final$;\n"
         "void InternalSwap($classname$* other);\n");
@@ -1661,8 +1661,7 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* p) {
       // protos to give access to this constructor, breaking the invariants
       // we rely on.
       "protected:\n"
-      "explicit $classname$(::$proto_ns$::Arena* arena,\n"
-      "                     bool is_message_owned = false);\n");
+      "explicit $classname$(::$proto_ns$::Arena* arena);\n");
 
   switch (NeedsArenaDestructor()) {
     case ArenaDtorNeeds::kOnDemand:
@@ -2332,10 +2331,8 @@ void MessageGenerator::GenerateSharedConstructorCode(io::Printer* p) {
   Formatter format(p);
 
   format(
-      "inline void $classname$::SharedCtor(\n"
-      "    ::_pb::Arena* arena, bool is_message_owned) {\n"
-      "  (void)arena;\n"
-      "  (void)is_message_owned;\n");
+      "inline void $classname$::SharedCtor(::_pb::Arena* arena) {\n"
+      "  (void)arena;\n");
 
   format.Indent();
   // Impl_ _impl_.
@@ -2424,13 +2421,7 @@ void MessageGenerator::GenerateSharedConstructorCode(io::Printer* p) {
     // is needed.
     format("if (arena != nullptr) {\n");
     if (NeedsArenaDestructor() == ArenaDtorNeeds::kOnDemand) {
-      format(
-          "  if (!is_message_owned) {\n"
-          "    $inlined_string_donated_array$[0] = ~0u;\n"
-          "  } else {\n"
-          // We should not register ArenaDtor for MOA.
-          "    $inlined_string_donated_array$[0] = 0xFFFFFFFEu;\n"
-          "  }\n");
+      format("  $inlined_string_donated_array$[0] = ~0u;\n");
     } else {
       format("  $inlined_string_donated_array$[0] = 0xFFFFFFFEu;\n");
     }
@@ -2750,16 +2741,15 @@ void MessageGenerator::GenerateStructors(io::Printer* p) {
   Formatter format(p);
 
   format(
-      "$classname$::$classname$(::$proto_ns$::Arena* arena,\n"
-      "                         bool is_message_owned)\n"
-      "  : $1$(arena, is_message_owned) {\n",
+      "$classname$::$classname$(::$proto_ns$::Arena* arena)\n"
+      "  : $1$(arena) {\n",
       SuperClassName(descriptor_, options_));
 
   if (!HasSimpleBaseClass(descriptor_, options_)) {
-    format("  SharedCtor(arena, is_message_owned);\n");
+    format("  SharedCtor(arena);\n");
     if (NeedsArenaDestructor() == ArenaDtorNeeds::kRequired) {
       format(
-          "  if (arena != nullptr && !is_message_owned) {\n"
+          "  if (arena != nullptr) {\n"
           "    arena->OwnCustomDestructor(this, &$classname$::ArenaDtor);\n"
           "  }\n");
     }
diff --git a/src/google/protobuf/compiler/plugin.pb.cc b/src/google/protobuf/compiler/plugin.pb.cc
index f77a0e3d81..f7ce36e016 100644
--- a/src/google/protobuf/compiler/plugin.pb.cc
+++ b/src/google/protobuf/compiler/plugin.pb.cc
@@ -286,10 +286,9 @@ class Version::_Internal {
   }
 };
 
-Version::Version(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+Version::Version(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.compiler.Version)
 }
 Version::Version(const Version& from)
@@ -318,10 +317,8 @@ Version::Version(const Version& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.compiler.Version)
 }
 
-inline void Version::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void Version::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -622,10 +619,9 @@ CodeGeneratorRequest::_Internal::compiler_version(const CodeGeneratorRequest* ms
 void CodeGeneratorRequest::clear_proto_file() {
   _impl_.proto_file_.Clear();
 }
-CodeGeneratorRequest::CodeGeneratorRequest(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+CodeGeneratorRequest::CodeGeneratorRequest(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.compiler.CodeGeneratorRequest)
 }
 CodeGeneratorRequest::CodeGeneratorRequest(const CodeGeneratorRequest& from)
@@ -654,10 +650,8 @@ CodeGeneratorRequest::CodeGeneratorRequest(const CodeGeneratorRequest& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.compiler.CodeGeneratorRequest)
 }
 
-inline void CodeGeneratorRequest::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void CodeGeneratorRequest::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -991,10 +985,9 @@ void CodeGeneratorResponse_File::clear_generated_code_info() {
   if (_impl_.generated_code_info_ != nullptr) _impl_.generated_code_info_->Clear();
   _impl_._has_bits_[0] &= ~0x00000008u;
 }
-CodeGeneratorResponse_File::CodeGeneratorResponse_File(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+CodeGeneratorResponse_File::CodeGeneratorResponse_File(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.compiler.CodeGeneratorResponse.File)
 }
 CodeGeneratorResponse_File::CodeGeneratorResponse_File(const CodeGeneratorResponse_File& from)
@@ -1039,10 +1032,8 @@ CodeGeneratorResponse_File::CodeGeneratorResponse_File(const CodeGeneratorRespon
   // @@protoc_insertion_point(copy_constructor:google.protobuf.compiler.CodeGeneratorResponse.File)
 }
 
-inline void CodeGeneratorResponse_File::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void CodeGeneratorResponse_File::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -1376,10 +1367,9 @@ class CodeGeneratorResponse::_Internal {
   }
 };
 
-CodeGeneratorResponse::CodeGeneratorResponse(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+CodeGeneratorResponse::CodeGeneratorResponse(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.compiler.CodeGeneratorResponse)
 }
 CodeGeneratorResponse::CodeGeneratorResponse(const CodeGeneratorResponse& from)
@@ -1405,10 +1395,8 @@ CodeGeneratorResponse::CodeGeneratorResponse(const CodeGeneratorResponse& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.compiler.CodeGeneratorResponse)
 }
 
-inline void CodeGeneratorResponse::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void CodeGeneratorResponse::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
diff --git a/src/google/protobuf/compiler/plugin.pb.h b/src/google/protobuf/compiler/plugin.pb.h
index eef8a5c705..5977c96527 100644
--- a/src/google/protobuf/compiler/plugin.pb.h
+++ b/src/google/protobuf/compiler/plugin.pb.h
@@ -222,7 +222,7 @@ class PROTOC_EXPORT Version final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(Version* other);
@@ -233,8 +233,7 @@ class PROTOC_EXPORT Version final :
     return "google.protobuf.compiler.Version";
   }
   protected:
-  explicit Version(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit Version(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -419,7 +418,7 @@ class PROTOC_EXPORT CodeGeneratorRequest final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(CodeGeneratorRequest* other);
@@ -430,8 +429,7 @@ class PROTOC_EXPORT CodeGeneratorRequest final :
     return "google.protobuf.compiler.CodeGeneratorRequest";
   }
   protected:
-  explicit CodeGeneratorRequest(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit CodeGeneratorRequest(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -643,7 +641,7 @@ class PROTOC_EXPORT CodeGeneratorResponse_File final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(CodeGeneratorResponse_File* other);
@@ -654,8 +652,7 @@ class PROTOC_EXPORT CodeGeneratorResponse_File final :
     return "google.protobuf.compiler.CodeGeneratorResponse.File";
   }
   protected:
-  explicit CodeGeneratorResponse_File(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit CodeGeneratorResponse_File(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -855,7 +852,7 @@ class PROTOC_EXPORT CodeGeneratorResponse final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(CodeGeneratorResponse* other);
@@ -866,8 +863,7 @@ class PROTOC_EXPORT CodeGeneratorResponse final :
     return "google.protobuf.compiler.CodeGeneratorResponse";
   }
   protected:
-  explicit CodeGeneratorResponse(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit CodeGeneratorResponse(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
diff --git a/src/google/protobuf/descriptor.pb.cc b/src/google/protobuf/descriptor.pb.cc
index 6b750b18be..6e187a66de 100644
--- a/src/google/protobuf/descriptor.pb.cc
+++ b/src/google/protobuf/descriptor.pb.cc
@@ -1481,10 +1481,9 @@ class FileDescriptorSet::_Internal {
  public:
 };
 
-FileDescriptorSet::FileDescriptorSet(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+FileDescriptorSet::FileDescriptorSet(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FileDescriptorSet)
 }
 FileDescriptorSet::FileDescriptorSet(const FileDescriptorSet& from)
@@ -1498,10 +1497,8 @@ FileDescriptorSet::FileDescriptorSet(const FileDescriptorSet& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FileDescriptorSet)
 }
 
-inline void FileDescriptorSet::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void FileDescriptorSet::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_.file_){arena}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -1704,10 +1701,9 @@ const ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo&
 FileDescriptorProto::_Internal::source_code_info(const FileDescriptorProto* msg) {
   return *msg->_impl_.source_code_info_;
 }
-FileDescriptorProto::FileDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+FileDescriptorProto::FileDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FileDescriptorProto)
 }
 FileDescriptorProto::FileDescriptorProto(const FileDescriptorProto& from)
@@ -1772,10 +1768,8 @@ FileDescriptorProto::FileDescriptorProto(const FileDescriptorProto& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FileDescriptorProto)
 }
 
-inline void FileDescriptorProto::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void FileDescriptorProto::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -2463,10 +2457,9 @@ const ::PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions&
 DescriptorProto_ExtensionRange::_Internal::options(const DescriptorProto_ExtensionRange* msg) {
   return *msg->_impl_.options_;
 }
-DescriptorProto_ExtensionRange::DescriptorProto_ExtensionRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+DescriptorProto_ExtensionRange::DescriptorProto_ExtensionRange(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.DescriptorProto.ExtensionRange)
 }
 DescriptorProto_ExtensionRange::DescriptorProto_ExtensionRange(const DescriptorProto_ExtensionRange& from)
@@ -2489,10 +2482,8 @@ DescriptorProto_ExtensionRange::DescriptorProto_ExtensionRange(const DescriptorP
   // @@protoc_insertion_point(copy_constructor:google.protobuf.DescriptorProto.ExtensionRange)
 }
 
-inline void DescriptorProto_ExtensionRange::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void DescriptorProto_ExtensionRange::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -2748,10 +2739,9 @@ class DescriptorProto_ReservedRange::_Internal {
   }
 };
 
-DescriptorProto_ReservedRange::DescriptorProto_ReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+DescriptorProto_ReservedRange::DescriptorProto_ReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.DescriptorProto.ReservedRange)
 }
 DescriptorProto_ReservedRange::DescriptorProto_ReservedRange(const DescriptorProto_ReservedRange& from)
@@ -2761,10 +2751,8 @@ DescriptorProto_ReservedRange::DescriptorProto_ReservedRange(const DescriptorPro
   // @@protoc_insertion_point(copy_constructor:google.protobuf.DescriptorProto.ReservedRange)
 }
 
-inline void DescriptorProto_ReservedRange::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void DescriptorProto_ReservedRange::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -2989,10 +2977,9 @@ const ::PROTOBUF_NAMESPACE_ID::MessageOptions&
 DescriptorProto::_Internal::options(const DescriptorProto* msg) {
   return *msg->_impl_.options_;
 }
-DescriptorProto::DescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+DescriptorProto::DescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.DescriptorProto)
 }
 DescriptorProto::DescriptorProto(const DescriptorProto& from)
@@ -3027,10 +3014,8 @@ DescriptorProto::DescriptorProto(const DescriptorProto& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.DescriptorProto)
 }
 
-inline void DescriptorProto::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void DescriptorProto::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -3557,10 +3542,9 @@ class ExtensionRangeOptions::_Internal {
  public:
 };
 
-ExtensionRangeOptions::ExtensionRangeOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+ExtensionRangeOptions::ExtensionRangeOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.ExtensionRangeOptions)
 }
 ExtensionRangeOptions::ExtensionRangeOptions(const ExtensionRangeOptions& from)
@@ -3576,10 +3560,8 @@ ExtensionRangeOptions::ExtensionRangeOptions(const ExtensionRangeOptions& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.ExtensionRangeOptions)
 }
 
-inline void ExtensionRangeOptions::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void ExtensionRangeOptions::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       /*decltype(_impl_._extensions_)*/{::_pbi::ArenaInitialized(), arena}
     , decltype(_impl_.uninterpreted_option_){arena}
@@ -3812,10 +3794,9 @@ const ::PROTOBUF_NAMESPACE_ID::FieldOptions&
 FieldDescriptorProto::_Internal::options(const FieldDescriptorProto* msg) {
   return *msg->_impl_.options_;
 }
-FieldDescriptorProto::FieldDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+FieldDescriptorProto::FieldDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FieldDescriptorProto)
 }
 FieldDescriptorProto::FieldDescriptorProto(const FieldDescriptorProto& from)
@@ -3886,10 +3867,8 @@ FieldDescriptorProto::FieldDescriptorProto(const FieldDescriptorProto& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FieldDescriptorProto)
 }
 
-inline void FieldDescriptorProto::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void FieldDescriptorProto::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -4481,10 +4460,9 @@ const ::PROTOBUF_NAMESPACE_ID::OneofOptions&
 OneofDescriptorProto::_Internal::options(const OneofDescriptorProto* msg) {
   return *msg->_impl_.options_;
 }
-OneofDescriptorProto::OneofDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+OneofDescriptorProto::OneofDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.OneofDescriptorProto)
 }
 OneofDescriptorProto::OneofDescriptorProto(const OneofDescriptorProto& from)
@@ -4511,10 +4489,8 @@ OneofDescriptorProto::OneofDescriptorProto(const OneofDescriptorProto& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.OneofDescriptorProto)
 }
 
-inline void OneofDescriptorProto::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void OneofDescriptorProto::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -4759,10 +4735,9 @@ class EnumDescriptorProto_EnumReservedRange::_Internal {
   }
 };
 
-EnumDescriptorProto_EnumReservedRange::EnumDescriptorProto_EnumReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+EnumDescriptorProto_EnumReservedRange::EnumDescriptorProto_EnumReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumDescriptorProto.EnumReservedRange)
 }
 EnumDescriptorProto_EnumReservedRange::EnumDescriptorProto_EnumReservedRange(const EnumDescriptorProto_EnumReservedRange& from)
@@ -4772,10 +4747,8 @@ EnumDescriptorProto_EnumReservedRange::EnumDescriptorProto_EnumReservedRange(con
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumDescriptorProto.EnumReservedRange)
 }
 
-inline void EnumDescriptorProto_EnumReservedRange::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void EnumDescriptorProto_EnumReservedRange::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -5000,10 +4973,9 @@ const ::PROTOBUF_NAMESPACE_ID::EnumOptions&
 EnumDescriptorProto::_Internal::options(const EnumDescriptorProto* msg) {
   return *msg->_impl_.options_;
 }
-EnumDescriptorProto::EnumDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+EnumDescriptorProto::EnumDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumDescriptorProto)
 }
 EnumDescriptorProto::EnumDescriptorProto(const EnumDescriptorProto& from)
@@ -5033,10 +5005,8 @@ EnumDescriptorProto::EnumDescriptorProto(const EnumDescriptorProto& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumDescriptorProto)
 }
 
-inline void EnumDescriptorProto::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void EnumDescriptorProto::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -5400,10 +5370,9 @@ const ::PROTOBUF_NAMESPACE_ID::EnumValueOptions&
 EnumValueDescriptorProto::_Internal::options(const EnumValueDescriptorProto* msg) {
   return *msg->_impl_.options_;
 }
-EnumValueDescriptorProto::EnumValueDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+EnumValueDescriptorProto::EnumValueDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumValueDescriptorProto)
 }
 EnumValueDescriptorProto::EnumValueDescriptorProto(const EnumValueDescriptorProto& from)
@@ -5432,10 +5401,8 @@ EnumValueDescriptorProto::EnumValueDescriptorProto(const EnumValueDescriptorProt
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumValueDescriptorProto)
 }
 
-inline void EnumValueDescriptorProto::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void EnumValueDescriptorProto::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -5717,10 +5684,9 @@ const ::PROTOBUF_NAMESPACE_ID::ServiceOptions&
 ServiceDescriptorProto::_Internal::options(const ServiceDescriptorProto* msg) {
   return *msg->_impl_.options_;
 }
-ServiceDescriptorProto::ServiceDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+ServiceDescriptorProto::ServiceDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.ServiceDescriptorProto)
 }
 ServiceDescriptorProto::ServiceDescriptorProto(const ServiceDescriptorProto& from)
@@ -5748,10 +5714,8 @@ ServiceDescriptorProto::ServiceDescriptorProto(const ServiceDescriptorProto& fro
   // @@protoc_insertion_point(copy_constructor:google.protobuf.ServiceDescriptorProto)
 }
 
-inline void ServiceDescriptorProto::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void ServiceDescriptorProto::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -6049,10 +6013,9 @@ const ::PROTOBUF_NAMESPACE_ID::MethodOptions&
 MethodDescriptorProto::_Internal::options(const MethodDescriptorProto* msg) {
   return *msg->_impl_.options_;
 }
-MethodDescriptorProto::MethodDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+MethodDescriptorProto::MethodDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.MethodDescriptorProto)
 }
 MethodDescriptorProto::MethodDescriptorProto(const MethodDescriptorProto& from)
@@ -6102,10 +6065,8 @@ MethodDescriptorProto::MethodDescriptorProto(const MethodDescriptorProto& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.MethodDescriptorProto)
 }
 
-inline void MethodDescriptorProto::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void MethodDescriptorProto::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -6555,10 +6516,9 @@ class FileOptions::_Internal {
   }
 };
 
-FileOptions::FileOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+FileOptions::FileOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FileOptions)
 }
 FileOptions::FileOptions(const FileOptions& from)
@@ -6678,10 +6638,8 @@ FileOptions::FileOptions(const FileOptions& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FileOptions)
 }
 
-inline void FileOptions::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void FileOptions::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       /*decltype(_impl_._extensions_)*/{::_pbi::ArenaInitialized(), arena}
     , decltype(_impl_._has_bits_){}
@@ -7651,10 +7609,9 @@ class MessageOptions::_Internal {
   }
 };
 
-MessageOptions::MessageOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+MessageOptions::MessageOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.MessageOptions)
 }
 MessageOptions::MessageOptions(const MessageOptions& from)
@@ -7678,10 +7635,8 @@ MessageOptions::MessageOptions(const MessageOptions& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.MessageOptions)
 }
 
-inline void MessageOptions::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void MessageOptions::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       /*decltype(_impl_._extensions_)*/{::_pbi::ArenaInitialized(), arena}
     , decltype(_impl_._has_bits_){}
@@ -8019,10 +7974,9 @@ class FieldOptions::_Internal {
   }
 };
 
-FieldOptions::FieldOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+FieldOptions::FieldOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.FieldOptions)
 }
 FieldOptions::FieldOptions(const FieldOptions& from)
@@ -8049,10 +8003,8 @@ FieldOptions::FieldOptions(const FieldOptions& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.FieldOptions)
 }
 
-inline void FieldOptions::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void FieldOptions::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       /*decltype(_impl_._extensions_)*/{::_pbi::ArenaInitialized(), arena}
     , decltype(_impl_._has_bits_){}
@@ -8456,10 +8408,9 @@ class OneofOptions::_Internal {
  public:
 };
 
-OneofOptions::OneofOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+OneofOptions::OneofOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.OneofOptions)
 }
 OneofOptions::OneofOptions(const OneofOptions& from)
@@ -8475,10 +8426,8 @@ OneofOptions::OneofOptions(const OneofOptions& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.OneofOptions)
 }
 
-inline void OneofOptions::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void OneofOptions::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       /*decltype(_impl_._extensions_)*/{::_pbi::ArenaInitialized(), arena}
     , decltype(_impl_.uninterpreted_option_){arena}
@@ -8679,10 +8628,9 @@ class EnumOptions::_Internal {
   }
 };
 
-EnumOptions::EnumOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+EnumOptions::EnumOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumOptions)
 }
 EnumOptions::EnumOptions(const EnumOptions& from)
@@ -8704,10 +8652,8 @@ EnumOptions::EnumOptions(const EnumOptions& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumOptions)
 }
 
-inline void EnumOptions::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void EnumOptions::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       /*decltype(_impl_._extensions_)*/{::_pbi::ArenaInitialized(), arena}
     , decltype(_impl_._has_bits_){}
@@ -8977,10 +8923,9 @@ class EnumValueOptions::_Internal {
   }
 };
 
-EnumValueOptions::EnumValueOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+EnumValueOptions::EnumValueOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.EnumValueOptions)
 }
 EnumValueOptions::EnumValueOptions(const EnumValueOptions& from)
@@ -8999,10 +8944,8 @@ EnumValueOptions::EnumValueOptions(const EnumValueOptions& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.EnumValueOptions)
 }
 
-inline void EnumValueOptions::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void EnumValueOptions::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       /*decltype(_impl_._extensions_)*/{::_pbi::ArenaInitialized(), arena}
     , decltype(_impl_._has_bits_){}
@@ -9234,10 +9177,9 @@ class ServiceOptions::_Internal {
   }
 };
 
-ServiceOptions::ServiceOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+ServiceOptions::ServiceOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.ServiceOptions)
 }
 ServiceOptions::ServiceOptions(const ServiceOptions& from)
@@ -9256,10 +9198,8 @@ ServiceOptions::ServiceOptions(const ServiceOptions& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.ServiceOptions)
 }
 
-inline void ServiceOptions::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void ServiceOptions::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       /*decltype(_impl_._extensions_)*/{::_pbi::ArenaInitialized(), arena}
     , decltype(_impl_._has_bits_){}
@@ -9494,10 +9434,9 @@ class MethodOptions::_Internal {
   }
 };
 
-MethodOptions::MethodOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+MethodOptions::MethodOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.MethodOptions)
 }
 MethodOptions::MethodOptions(const MethodOptions& from)
@@ -9519,10 +9458,8 @@ MethodOptions::MethodOptions(const MethodOptions& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.MethodOptions)
 }
 
-inline void MethodOptions::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void MethodOptions::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       /*decltype(_impl_._extensions_)*/{::_pbi::ArenaInitialized(), arena}
     , decltype(_impl_._has_bits_){}
@@ -9807,10 +9744,9 @@ class UninterpretedOption_NamePart::_Internal {
   }
 };
 
-UninterpretedOption_NamePart::UninterpretedOption_NamePart(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+UninterpretedOption_NamePart::UninterpretedOption_NamePart(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.UninterpretedOption.NamePart)
 }
 UninterpretedOption_NamePart::UninterpretedOption_NamePart(const UninterpretedOption_NamePart& from)
@@ -9835,10 +9771,8 @@ UninterpretedOption_NamePart::UninterpretedOption_NamePart(const UninterpretedOp
   // @@protoc_insertion_point(copy_constructor:google.protobuf.UninterpretedOption.NamePart)
 }
 
-inline void UninterpretedOption_NamePart::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void UninterpretedOption_NamePart::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -10100,10 +10034,9 @@ class UninterpretedOption::_Internal {
   }
 };
 
-UninterpretedOption::UninterpretedOption(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+UninterpretedOption::UninterpretedOption(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.UninterpretedOption)
 }
 UninterpretedOption::UninterpretedOption(const UninterpretedOption& from)
@@ -10151,10 +10084,8 @@ UninterpretedOption::UninterpretedOption(const UninterpretedOption& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.UninterpretedOption)
 }
 
-inline void UninterpretedOption::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void UninterpretedOption::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -10570,10 +10501,9 @@ class SourceCodeInfo_Location::_Internal {
   }
 };
 
-SourceCodeInfo_Location::SourceCodeInfo_Location(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+SourceCodeInfo_Location::SourceCodeInfo_Location(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.SourceCodeInfo.Location)
 }
 SourceCodeInfo_Location::SourceCodeInfo_Location(const SourceCodeInfo_Location& from)
@@ -10610,10 +10540,8 @@ SourceCodeInfo_Location::SourceCodeInfo_Location(const SourceCodeInfo_Location&
   // @@protoc_insertion_point(copy_constructor:google.protobuf.SourceCodeInfo.Location)
 }
 
-inline void SourceCodeInfo_Location::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void SourceCodeInfo_Location::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -10979,10 +10907,9 @@ class SourceCodeInfo::_Internal {
  public:
 };
 
-SourceCodeInfo::SourceCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+SourceCodeInfo::SourceCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.SourceCodeInfo)
 }
 SourceCodeInfo::SourceCodeInfo(const SourceCodeInfo& from)
@@ -10996,10 +10923,8 @@ SourceCodeInfo::SourceCodeInfo(const SourceCodeInfo& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.SourceCodeInfo)
 }
 
-inline void SourceCodeInfo::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void SourceCodeInfo::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_.location_){arena}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -11184,10 +11109,9 @@ class GeneratedCodeInfo_Annotation::_Internal {
   }
 };
 
-GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.GeneratedCodeInfo.Annotation)
 }
 GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(const GeneratedCodeInfo_Annotation& from)
@@ -11218,10 +11142,8 @@ GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(const GeneratedCodeIn
   // @@protoc_insertion_point(copy_constructor:google.protobuf.GeneratedCodeInfo.Annotation)
 }
 
-inline void GeneratedCodeInfo_Annotation::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void GeneratedCodeInfo_Annotation::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_._has_bits_){}
     , /*decltype(_impl_._cached_size_)*/{}
@@ -11551,10 +11473,9 @@ class GeneratedCodeInfo::_Internal {
  public:
 };
 
-GeneratedCodeInfo::GeneratedCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                         bool is_message_owned)
-  : ::PROTOBUF_NAMESPACE_ID::Message(arena, is_message_owned) {
-  SharedCtor(arena, is_message_owned);
+GeneratedCodeInfo::GeneratedCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena)
+  : ::PROTOBUF_NAMESPACE_ID::Message(arena) {
+  SharedCtor(arena);
   // @@protoc_insertion_point(arena_constructor:google.protobuf.GeneratedCodeInfo)
 }
 GeneratedCodeInfo::GeneratedCodeInfo(const GeneratedCodeInfo& from)
@@ -11568,10 +11489,8 @@ GeneratedCodeInfo::GeneratedCodeInfo(const GeneratedCodeInfo& from)
   // @@protoc_insertion_point(copy_constructor:google.protobuf.GeneratedCodeInfo)
 }
 
-inline void GeneratedCodeInfo::SharedCtor(
-    ::_pb::Arena* arena, bool is_message_owned) {
+inline void GeneratedCodeInfo::SharedCtor(::_pb::Arena* arena) {
   (void)arena;
-  (void)is_message_owned;
   new (&_impl_) Impl_{
       decltype(_impl_.annotation_){arena}
     , /*decltype(_impl_._cached_size_)*/{}
diff --git a/src/google/protobuf/descriptor.pb.h b/src/google/protobuf/descriptor.pb.h
index 56a2233f52..0995d792e6 100644
--- a/src/google/protobuf/descriptor.pb.h
+++ b/src/google/protobuf/descriptor.pb.h
@@ -517,7 +517,7 @@ class PROTOBUF_EXPORT FileDescriptorSet final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(FileDescriptorSet* other);
@@ -528,8 +528,7 @@ class PROTOBUF_EXPORT FileDescriptorSet final :
     return "google.protobuf.FileDescriptorSet";
   }
   protected:
-  explicit FileDescriptorSet(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit FileDescriptorSet(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -680,7 +679,7 @@ class PROTOBUF_EXPORT FileDescriptorProto final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(FileDescriptorProto* other);
@@ -691,8 +690,7 @@ class PROTOBUF_EXPORT FileDescriptorProto final :
     return "google.protobuf.FileDescriptorProto";
   }
   protected:
-  explicit FileDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit FileDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -1080,7 +1078,7 @@ class PROTOBUF_EXPORT DescriptorProto_ExtensionRange final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(DescriptorProto_ExtensionRange* other);
@@ -1091,8 +1089,7 @@ class PROTOBUF_EXPORT DescriptorProto_ExtensionRange final :
     return "google.protobuf.DescriptorProto.ExtensionRange";
   }
   protected:
-  explicit DescriptorProto_ExtensionRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit DescriptorProto_ExtensionRange(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -1265,7 +1262,7 @@ class PROTOBUF_EXPORT DescriptorProto_ReservedRange final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(DescriptorProto_ReservedRange* other);
@@ -1276,8 +1273,7 @@ class PROTOBUF_EXPORT DescriptorProto_ReservedRange final :
     return "google.protobuf.DescriptorProto.ReservedRange";
   }
   protected:
-  explicit DescriptorProto_ReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit DescriptorProto_ReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -1433,7 +1429,7 @@ class PROTOBUF_EXPORT DescriptorProto final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(DescriptorProto* other);
@@ -1444,8 +1440,7 @@ class PROTOBUF_EXPORT DescriptorProto final :
     return "google.protobuf.DescriptorProto";
   }
   protected:
-  explicit DescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit DescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -1780,7 +1775,7 @@ class PROTOBUF_EXPORT ExtensionRangeOptions final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(ExtensionRangeOptions* other);
@@ -1791,8 +1786,7 @@ class PROTOBUF_EXPORT ExtensionRangeOptions final :
     return "google.protobuf.ExtensionRangeOptions";
   }
   protected:
-  explicit ExtensionRangeOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit ExtensionRangeOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -2135,7 +2129,7 @@ class PROTOBUF_EXPORT FieldDescriptorProto final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(FieldDescriptorProto* other);
@@ -2146,8 +2140,7 @@ class PROTOBUF_EXPORT FieldDescriptorProto final :
     return "google.protobuf.FieldDescriptorProto";
   }
   protected:
-  explicit FieldDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit FieldDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -2498,7 +2491,7 @@ class PROTOBUF_EXPORT OneofDescriptorProto final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(OneofDescriptorProto* other);
@@ -2509,8 +2502,7 @@ class PROTOBUF_EXPORT OneofDescriptorProto final :
     return "google.protobuf.OneofDescriptorProto";
   }
   protected:
-  explicit OneofDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit OneofDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -2676,7 +2668,7 @@ class PROTOBUF_EXPORT EnumDescriptorProto_EnumReservedRange final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(EnumDescriptorProto_EnumReservedRange* other);
@@ -2687,8 +2679,7 @@ class PROTOBUF_EXPORT EnumDescriptorProto_EnumReservedRange final :
     return "google.protobuf.EnumDescriptorProto.EnumReservedRange";
   }
   protected:
-  explicit EnumDescriptorProto_EnumReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit EnumDescriptorProto_EnumReservedRange(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -2844,7 +2835,7 @@ class PROTOBUF_EXPORT EnumDescriptorProto final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(EnumDescriptorProto* other);
@@ -2855,8 +2846,7 @@ class PROTOBUF_EXPORT EnumDescriptorProto final :
     return "google.protobuf.EnumDescriptorProto";
   }
   protected:
-  explicit EnumDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit EnumDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -3090,7 +3080,7 @@ class PROTOBUF_EXPORT EnumValueDescriptorProto final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(EnumValueDescriptorProto* other);
@@ -3101,8 +3091,7 @@ class PROTOBUF_EXPORT EnumValueDescriptorProto final :
     return "google.protobuf.EnumValueDescriptorProto";
   }
   protected:
-  explicit EnumValueDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit EnumValueDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -3280,7 +3269,7 @@ class PROTOBUF_EXPORT ServiceDescriptorProto final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(ServiceDescriptorProto* other);
@@ -3291,8 +3280,7 @@ class PROTOBUF_EXPORT ServiceDescriptorProto final :
     return "google.protobuf.ServiceDescriptorProto";
   }
   protected:
-  explicit ServiceDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit ServiceDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -3478,7 +3466,7 @@ class PROTOBUF_EXPORT MethodDescriptorProto final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(MethodDescriptorProto* other);
@@ -3489,8 +3477,7 @@ class PROTOBUF_EXPORT MethodDescriptorProto final :
     return "google.protobuf.MethodDescriptorProto";
   }
   protected:
-  explicit MethodDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit MethodDescriptorProto(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -3714,7 +3701,7 @@ class PROTOBUF_EXPORT FileOptions final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(FileOptions* other);
@@ -3725,8 +3712,7 @@ class PROTOBUF_EXPORT FileOptions final :
     return "google.protobuf.FileOptions";
   }
   protected:
-  explicit FileOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit FileOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -4381,7 +4367,7 @@ class PROTOBUF_EXPORT MessageOptions final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(MessageOptions* other);
@@ -4392,8 +4378,7 @@ class PROTOBUF_EXPORT MessageOptions final :
     return "google.protobuf.MessageOptions";
   }
   protected:
-  explicit MessageOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit MessageOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -4785,7 +4770,7 @@ class PROTOBUF_EXPORT FieldOptions final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(FieldOptions* other);
@@ -4796,8 +4781,7 @@ class PROTOBUF_EXPORT FieldOptions final :
     return "google.protobuf.FieldOptions";
   }
   protected:
-  explicit FieldOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit FieldOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -5267,7 +5251,7 @@ class PROTOBUF_EXPORT OneofOptions final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(OneofOptions* other);
@@ -5278,8 +5262,7 @@ class PROTOBUF_EXPORT OneofOptions final :
     return "google.protobuf.OneofOptions";
   }
   protected:
-  explicit OneofOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit OneofOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -5622,7 +5605,7 @@ class PROTOBUF_EXPORT EnumOptions final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(EnumOptions* other);
@@ -5633,8 +5616,7 @@ class PROTOBUF_EXPORT EnumOptions final :
     return "google.protobuf.EnumOptions";
   }
   protected:
-  explicit EnumOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit EnumOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -6002,7 +5984,7 @@ class PROTOBUF_EXPORT EnumValueOptions final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(EnumValueOptions* other);
@@ -6013,8 +5995,7 @@ class PROTOBUF_EXPORT EnumValueOptions final :
     return "google.protobuf.EnumValueOptions";
   }
   protected:
-  explicit EnumValueOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit EnumValueOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -6370,7 +6351,7 @@ class PROTOBUF_EXPORT ServiceOptions final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(ServiceOptions* other);
@@ -6381,8 +6362,7 @@ class PROTOBUF_EXPORT ServiceOptions final :
     return "google.protobuf.ServiceOptions";
   }
   protected:
-  explicit ServiceOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit ServiceOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -6738,7 +6718,7 @@ class PROTOBUF_EXPORT MethodOptions final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(MethodOptions* other);
@@ -6749,8 +6729,7 @@ class PROTOBUF_EXPORT MethodOptions final :
     return "google.protobuf.MethodOptions";
   }
   protected:
-  explicit MethodOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit MethodOptions(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -7139,7 +7118,7 @@ class PROTOBUF_EXPORT UninterpretedOption_NamePart final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(UninterpretedOption_NamePart* other);
@@ -7150,8 +7129,7 @@ class PROTOBUF_EXPORT UninterpretedOption_NamePart final :
     return "google.protobuf.UninterpretedOption.NamePart";
   }
   protected:
-  explicit UninterpretedOption_NamePart(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit UninterpretedOption_NamePart(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -7315,7 +7293,7 @@ class PROTOBUF_EXPORT UninterpretedOption final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(UninterpretedOption* other);
@@ -7326,8 +7304,7 @@ class PROTOBUF_EXPORT UninterpretedOption final :
     return "google.protobuf.UninterpretedOption";
   }
   protected:
-  explicit UninterpretedOption(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit UninterpretedOption(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -7568,7 +7545,7 @@ class PROTOBUF_EXPORT SourceCodeInfo_Location final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(SourceCodeInfo_Location* other);
@@ -7579,8 +7556,7 @@ class PROTOBUF_EXPORT SourceCodeInfo_Location final :
     return "google.protobuf.SourceCodeInfo.Location";
   }
   protected:
-  explicit SourceCodeInfo_Location(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit SourceCodeInfo_Location(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -7822,7 +7798,7 @@ class PROTOBUF_EXPORT SourceCodeInfo final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(SourceCodeInfo* other);
@@ -7833,8 +7809,7 @@ class PROTOBUF_EXPORT SourceCodeInfo final :
     return "google.protobuf.SourceCodeInfo";
   }
   protected:
-  explicit SourceCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit SourceCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -7987,7 +7962,7 @@ class PROTOBUF_EXPORT GeneratedCodeInfo_Annotation final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(GeneratedCodeInfo_Annotation* other);
@@ -7998,8 +7973,7 @@ class PROTOBUF_EXPORT GeneratedCodeInfo_Annotation final :
     return "google.protobuf.GeneratedCodeInfo.Annotation";
   }
   protected:
-  explicit GeneratedCodeInfo_Annotation(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit GeneratedCodeInfo_Annotation(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
@@ -8230,7 +8204,7 @@ class PROTOBUF_EXPORT GeneratedCodeInfo final :
   int GetCachedSize() const final { return _impl_._cached_size_.Get(); }
 
   private:
-  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena, bool is_message_owned);
+  void SharedCtor(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   void SharedDtor();
   void SetCachedSize(int size) const final;
   void InternalSwap(GeneratedCodeInfo* other);
@@ -8241,8 +8215,7 @@ class PROTOBUF_EXPORT GeneratedCodeInfo final :
     return "google.protobuf.GeneratedCodeInfo";
   }
   protected:
-  explicit GeneratedCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena,
-                       bool is_message_owned = false);
+  explicit GeneratedCodeInfo(::PROTOBUF_NAMESPACE_ID::Arena* arena);
   public:
 
   static const ClassData _class_data_;
diff --git a/src/google/protobuf/generated_message_bases.h b/src/google/protobuf/generated_message_bases.h
index d542ca414e..23798cc4c7 100644
--- a/src/google/protobuf/generated_message_bases.h
+++ b/src/google/protobuf/generated_message_bases.h
@@ -63,8 +63,7 @@ class PROTOBUF_EXPORT ZeroFieldsBase : public Message {
 
  protected:
   constexpr ZeroFieldsBase() {}
-  explicit ZeroFieldsBase(Arena* arena, bool is_message_owned)
-      : Message(arena, is_message_owned) {}
+  explicit ZeroFieldsBase(Arena* arena) : Message(arena) {}
   ZeroFieldsBase(const ZeroFieldsBase&) = delete;
   ZeroFieldsBase& operator=(const ZeroFieldsBase&) = delete;
   ~ZeroFieldsBase() override;
diff --git a/src/google/protobuf/message.h b/src/google/protobuf/message.h
index f08b3466c1..2813c27009 100644
--- a/src/google/protobuf/message.h
+++ b/src/google/protobuf/message.h
@@ -415,8 +415,7 @@ class PROTOBUF_EXPORT Message : public MessageLite {
   // Fail if "from" is a descendant of "to" as such copy is not allowed.
   static void FailIfCopyFromDescendant(Message& to, const Message& from);
 
-  inline explicit Message(Arena* arena, bool is_message_owned = false)
-      : MessageLite(arena, is_message_owned) {}
+  inline explicit Message(Arena* arena) : MessageLite(arena) {}
   size_t ComputeUnknownFieldsSize(size_t total_size,
                                   internal::CachedSize* cached_size) const;
   size_t MaybeComputeUnknownFieldsSize(size_t total_size,
diff --git a/src/google/protobuf/message_lite.cc b/src/google/protobuf/message_lite.cc
index 2cbb77ad72..624ab85105 100644
--- a/src/google/protobuf/message_lite.cc
+++ b/src/google/protobuf/message_lite.cc
@@ -63,10 +63,6 @@
 namespace google {
 namespace protobuf {
 
-MessageLite::~MessageLite(){
-// Defined out of line to save code space
-}
-
 std::string MessageLite::InitializationErrorString() const {
   return "(cannot determine missing fields for lite message)";
 }
@@ -515,15 +511,6 @@ void GenericTypeHandler<std::string>::Merge(const std::string& from,
   *to = from;
 }
 
-// Non-inline implementations of InternalMetadata destructor
-// This is moved out of the header because the GOOGLE_DCHECK produces a lot of code.
-void InternalMetadata::CheckedDestruct() {
-  if (HasMessageOwnedArenaTag()) {
-    GOOGLE_DCHECK(!HasUnknownFieldsTag());
-    delete reinterpret_cast<Arena*>(ptr_ - kMessageOwnedArenaTagMask);
-  }
-}
-
 // Non-inline variants of std::string specializations for
 // various InternalMetadata routines.
 template <>
diff --git a/src/google/protobuf/message_lite.h b/src/google/protobuf/message_lite.h
index 0ce91cde8d..35db842b11 100644
--- a/src/google/protobuf/message_lite.h
+++ b/src/google/protobuf/message_lite.h
@@ -172,7 +172,7 @@ class PROTOBUF_EXPORT MessageLite {
   constexpr MessageLite() {}
   MessageLite(const MessageLite&) = delete;
   MessageLite& operator=(const MessageLite&) = delete;
-  virtual ~MessageLite();
+  virtual ~MessageLite() = default;
 
   // Basic Operations ------------------------------------------------
 
@@ -429,8 +429,7 @@ class PROTOBUF_EXPORT MessageLite {
     return Arena::CreateMaybeMessage<T>(arena);
   }
 
-  inline explicit MessageLite(Arena* arena, bool is_message_owned = false)
-      : _internal_metadata_(arena, is_message_owned) {}
+  inline explicit MessageLite(Arena* arena) : _internal_metadata_(arena) {}
 
   // Returns the arena, if any, that directly owns this message and its internal
   // memory (Arena::Own is different in that the arena doesn't directly own the
diff --git a/src/google/protobuf/metadata_lite.h b/src/google/protobuf/metadata_lite.h
index 0700327dcd..cb75e57e07 100644
--- a/src/google/protobuf/metadata_lite.h
+++ b/src/google/protobuf/metadata_lite.h
@@ -67,29 +67,8 @@ namespace internal {
 class PROTOBUF_EXPORT InternalMetadata {
  public:
   constexpr InternalMetadata() : ptr_(0) {}
-  explicit InternalMetadata(Arena* arena, bool is_message_owned = false) {
-    SetArena(arena, is_message_owned);
-  }
-
-  void SetArena(Arena* arena, bool is_message_owned) {
-    ptr_ = is_message_owned
-               ? reinterpret_cast<intptr_t>(arena) | kMessageOwnedArenaTagMask
-               : reinterpret_cast<intptr_t>(arena);
-    GOOGLE_DCHECK(!is_message_owned || arena != nullptr);
-  }
-
-  // To keep the ABI identical between debug and non-debug builds,
-  // the destructor is always defined here even though it may delegate
-  // to a non-inline private method.
-  // (see https://github.com/protocolbuffers/protobuf/issues/9947)
-  ~InternalMetadata() {
-#if defined(NDEBUG) || defined(_MSC_VER)
-    if (HasMessageOwnedArenaTag()) {
-      delete reinterpret_cast<Arena*>(ptr_ - kMessageOwnedArenaTagMask);
-    }
-#else
-    CheckedDestruct();
-#endif
+  explicit InternalMetadata(Arena* arena) {
+    ptr_ = reinterpret_cast<intptr_t>(arena);
   }
 
   template <typename T>
@@ -116,14 +95,9 @@ class PROTOBUF_EXPORT InternalMetadata {
     }
   }
 
-  PROTOBUF_NDEBUG_INLINE Arena* owning_arena() const {
-    return HasMessageOwnedArenaTag() ? nullptr : arena();
-  }
+  PROTOBUF_NDEBUG_INLINE Arena* owning_arena() const { return arena(); }
 
-  PROTOBUF_NDEBUG_INLINE Arena* user_arena() const {
-    Arena* a = arena();
-    return a && !a->IsMessageOwned() ? a : nullptr;
-  }
+  PROTOBUF_NDEBUG_INLINE Arena* user_arena() const { return arena(); }
 
   PROTOBUF_NDEBUG_INLINE Arena* arena() const {
     if (PROTOBUF_PREDICT_FALSE(have_unknown_fields())) {
@@ -196,18 +170,13 @@ class PROTOBUF_EXPORT InternalMetadata {
 
   // Tagged pointer implementation.
   static constexpr intptr_t kUnknownFieldsTagMask = 1;
-  static constexpr intptr_t kMessageOwnedArenaTagMask = 2;
-  static constexpr intptr_t kPtrTagMask =
-      kUnknownFieldsTagMask | kMessageOwnedArenaTagMask;
+  static constexpr intptr_t kPtrTagMask = kUnknownFieldsTagMask;
   static constexpr intptr_t kPtrValueMask = ~kPtrTagMask;
 
   // Accessors for pointer tag and pointer value.
   PROTOBUF_ALWAYS_INLINE bool HasUnknownFieldsTag() const {
     return ptr_ & kUnknownFieldsTagMask;
   }
-  PROTOBUF_ALWAYS_INLINE bool HasMessageOwnedArenaTag() const {
-    return ptr_ & kMessageOwnedArenaTagMask;
-  }
 
   template <typename U>
   U* PtrValue() const {
@@ -227,11 +196,7 @@ class PROTOBUF_EXPORT InternalMetadata {
   template <typename T>
   PROTOBUF_NOINLINE Arena* DeleteOutOfLineHelper() {
     if (auto* a = arena()) {
-      // Subtle: we want to preserve the message-owned arena flag, while at the
-      // same time replacing the pointer to Container<T> with a pointer to the
-      // arena.
-      intptr_t message_owned_arena_tag = ptr_ & kMessageOwnedArenaTagMask;
-      ptr_ = reinterpret_cast<intptr_t>(a) | message_owned_arena_tag;
+      ptr_ = reinterpret_cast<intptr_t>(a);
       return a;
     } else {
       delete PtrValue<Container<T>>();
@@ -244,11 +209,10 @@ class PROTOBUF_EXPORT InternalMetadata {
   PROTOBUF_NOINLINE T* mutable_unknown_fields_slow() {
     Arena* my_arena = arena();
     Container<T>* container = Arena::Create<Container<T>>(my_arena);
-    intptr_t message_owned_arena_tag = ptr_ & kMessageOwnedArenaTagMask;
     // Two-step assignment works around a bug in clang's static analyzer:
     // https://bugs.llvm.org/show_bug.cgi?id=34198.
     ptr_ = reinterpret_cast<intptr_t>(container);
-    ptr_ |= kUnknownFieldsTagMask | message_owned_arena_tag;
+    ptr_ |= kUnknownFieldsTagMask;
     container->arena = my_arena;
     return &(container->unknown_fields);
   }