diff --git a/python/google/protobuf/pyext/message.cc b/python/google/protobuf/pyext/message.cc
index cb48faa440..097d6bf9e8 100644
--- a/python/google/protobuf/pyext/message.cc
+++ b/python/google/protobuf/pyext/message.cc
@@ -1074,7 +1074,7 @@ int InitAttributes(CMessage* self, PyObject* args, PyObject* kwargs) {
     if (descriptor->is_map()) {
       ScopedPyObjectPtr map(GetFieldValue(self, descriptor));
       const FieldDescriptor* value_descriptor =
-          descriptor->message_type()->FindFieldByName("value");
+          descriptor->message_type()->map_value();
       if (value_descriptor->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
         ScopedPyObjectPtr iter(PyObject_GetIter(value));
         if (iter == NULL) {
@@ -2582,7 +2582,7 @@ PyObject* GetFieldValue(CMessage* self,
   ContainerBase* py_container = nullptr;
   if (field_descriptor->is_map()) {
     const Descriptor* entry_type = field_descriptor->message_type();
-    const FieldDescriptor* value_type = entry_type->FindFieldByName("value");
+    const FieldDescriptor* value_type = entry_type->map_value();
     if (value_type->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
       CMessageClass* value_class = message_factory::GetMessageClass(
           GetFactoryForMessage(self), value_type->message_type());
diff --git a/src/google/protobuf/compiler/cpp/cpp_map_field.cc b/src/google/protobuf/compiler/cpp/cpp_map_field.cc
index 130e90ebbe..96f512d6c7 100644
--- a/src/google/protobuf/compiler/cpp/cpp_map_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_map_field.cc
@@ -54,9 +54,9 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
   (*variables)["full_name"] = descriptor->full_name();
 
   const FieldDescriptor* key =
-      descriptor->message_type()->FindFieldByName("key");
+      descriptor->message_type()->map_key();
   const FieldDescriptor* val =
-      descriptor->message_type()->FindFieldByName("value");
+      descriptor->message_type()->map_value();
   (*variables)["key_cpp"] = PrimitiveTypeName(options, key->cpp_type());
   switch (val->cpp_type()) {
     case FieldDescriptor::CPPTYPE_MESSAGE:
@@ -207,9 +207,9 @@ void MapFieldGenerator::GenerateSerializeWithCachedSizesToArray(
   format("if (!this->_internal_$name$().empty()) {\n");
   format.Indent();
   const FieldDescriptor* key_field =
-      descriptor_->message_type()->FindFieldByName("key");
+      descriptor_->message_type()->map_key();
   const FieldDescriptor* value_field =
-      descriptor_->message_type()->FindFieldByName("value");
+      descriptor_->message_type()->map_value();
   const bool string_key = key_field->type() == FieldDescriptor::TYPE_STRING;
   const bool string_value = value_field->type() == FieldDescriptor::TYPE_STRING;
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_message.cc b/src/google/protobuf/compiler/cpp/cpp_message.cc
index 70d8a57e3a..13850460f0 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message.cc
@@ -276,8 +276,8 @@ void CollectMapInfo(const Options& options, const Descriptor* descriptor,
                     std::map<std::string, std::string>* variables) {
   GOOGLE_CHECK(IsMapEntryMessage(descriptor));
   std::map<std::string, std::string>& vars = *variables;
-  const FieldDescriptor* key = descriptor->FindFieldByName("key");
-  const FieldDescriptor* val = descriptor->FindFieldByName("value");
+  const FieldDescriptor* key = descriptor->map_key();
+  const FieldDescriptor* val = descriptor->map_value();
   vars["key_cpp"] = PrimitiveTypeName(options, key->cpp_type());
   switch (val->cpp_type()) {
     case FieldDescriptor::CPPTYPE_MESSAGE:
diff --git a/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc b/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc
index 810f240a89..027bf82d88 100644
--- a/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc
@@ -752,7 +752,7 @@ void ParseFunctionGenerator::GenerateLengthDelim(Formatter& format,
       case FieldDescriptor::TYPE_MESSAGE: {
         if (field->is_map()) {
           const FieldDescriptor* val =
-              field->message_type()->FindFieldByName("value");
+              field->message_type()->map_value();
           GOOGLE_CHECK(val);
           if (val->type() == FieldDescriptor::TYPE_ENUM &&
               !HasPreservingUnknownEnumSemantics(field)) {
diff --git a/src/google/protobuf/compiler/csharp/csharp_map_field.cc b/src/google/protobuf/compiler/csharp/csharp_map_field.cc
index 44c13e2f63..a13b995da8 100644
--- a/src/google/protobuf/compiler/csharp/csharp_map_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_map_field.cc
@@ -57,9 +57,9 @@ MapFieldGenerator::~MapFieldGenerator() {
 
 void MapFieldGenerator::GenerateMembers(io::Printer* printer) {
   const FieldDescriptor* key_descriptor =
-      descriptor_->message_type()->FindFieldByName("key");
+      descriptor_->message_type()->map_key();
   const FieldDescriptor* value_descriptor =
-      descriptor_->message_type()->FindFieldByName("value");
+      descriptor_->message_type()->map_value();
   variables_["key_type_name"] = type_name(key_descriptor);
   variables_["value_type_name"] = type_name(value_descriptor);
   std::unique_ptr<FieldGeneratorBase> key_generator(
diff --git a/src/google/protobuf/compiler/java/java_helpers.cc b/src/google/protobuf/compiler/java/java_helpers.cc
index f37ecde784..1b1aebff34 100644
--- a/src/google/protobuf/compiler/java/java_helpers.cc
+++ b/src/google/protobuf/compiler/java/java_helpers.cc
@@ -1050,7 +1050,7 @@ int GetExperimentalJavaFieldType(const FieldDescriptor* field) {
   if (field->is_map()) {
     if (!SupportUnknownEnumValue(field)) {
       const FieldDescriptor* value =
-          field->message_type()->FindFieldByName("value");
+          field->message_type()->map_value();
       if (GetJavaType(value) == JAVATYPE_ENUM) {
         extra_bits |= kMapWithProto2EnumValue;
       }
diff --git a/src/google/protobuf/compiler/java/java_map_field.cc b/src/google/protobuf/compiler/java/java_map_field.cc
index 8a89100714..74d43bbc34 100644
--- a/src/google/protobuf/compiler/java/java_map_field.cc
+++ b/src/google/protobuf/compiler/java/java_map_field.cc
@@ -47,14 +47,14 @@ const FieldDescriptor* KeyField(const FieldDescriptor* descriptor) {
   GOOGLE_CHECK_EQ(FieldDescriptor::TYPE_MESSAGE, descriptor->type());
   const Descriptor* message = descriptor->message_type();
   GOOGLE_CHECK(message->options().map_entry());
-  return message->FindFieldByName("key");
+  return message->map_key();
 }
 
 const FieldDescriptor* ValueField(const FieldDescriptor* descriptor) {
   GOOGLE_CHECK_EQ(FieldDescriptor::TYPE_MESSAGE, descriptor->type());
   const Descriptor* message = descriptor->message_type();
   GOOGLE_CHECK(message->options().map_entry());
-  return message->FindFieldByName("value");
+  return message->map_value();
 }
 
 std::string TypeName(const FieldDescriptor* field,
diff --git a/src/google/protobuf/compiler/java/java_map_field_lite.cc b/src/google/protobuf/compiler/java/java_map_field_lite.cc
index e71116866e..dac3ae93fb 100644
--- a/src/google/protobuf/compiler/java/java_map_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_map_field_lite.cc
@@ -49,14 +49,14 @@ const FieldDescriptor* KeyField(const FieldDescriptor* descriptor) {
   GOOGLE_CHECK_EQ(FieldDescriptor::TYPE_MESSAGE, descriptor->type());
   const Descriptor* message = descriptor->message_type();
   GOOGLE_CHECK(message->options().map_entry());
-  return message->FindFieldByName("key");
+  return message->map_key();
 }
 
 const FieldDescriptor* ValueField(const FieldDescriptor* descriptor) {
   GOOGLE_CHECK_EQ(FieldDescriptor::TYPE_MESSAGE, descriptor->type());
   const Descriptor* message = descriptor->message_type();
   GOOGLE_CHECK(message->options().map_entry());
-  return message->FindFieldByName("value");
+  return message->map_value();
 }
 
 std::string TypeName(const FieldDescriptor* field,
diff --git a/src/google/protobuf/compiler/java/java_message.cc b/src/google/protobuf/compiler/java/java_message.cc
index 27d1014f69..8fdd115c7c 100644
--- a/src/google/protobuf/compiler/java/java_message.cc
+++ b/src/google/protobuf/compiler/java/java_message.cc
@@ -67,7 +67,7 @@ using internal::WireFormatLite;
 namespace {
 std::string MapValueImmutableClassdName(const Descriptor* descriptor,
                                         ClassNameResolver* name_resolver) {
-  const FieldDescriptor* value_field = descriptor->FindFieldByName("value");
+  const FieldDescriptor* value_field = descriptor->map_value();
   GOOGLE_CHECK_EQ(FieldDescriptor::TYPE_MESSAGE, value_field->type());
   return name_resolver->GetImmutableClassName(value_field->message_type());
 }
diff --git a/src/google/protobuf/compiler/java/java_message_builder.cc b/src/google/protobuf/compiler/java/java_message_builder.cc
index 320852b1be..b44015cbd9 100644
--- a/src/google/protobuf/compiler/java/java_message_builder.cc
+++ b/src/google/protobuf/compiler/java/java_message_builder.cc
@@ -61,7 +61,7 @@ namespace java {
 namespace {
 std::string MapValueImmutableClassdName(const Descriptor* descriptor,
                                         ClassNameResolver* name_resolver) {
-  const FieldDescriptor* value_field = descriptor->FindFieldByName("value");
+  const FieldDescriptor* value_field = descriptor->map_value();
   GOOGLE_CHECK_EQ(FieldDescriptor::TYPE_MESSAGE, value_field->type());
   return name_resolver->GetImmutableClassName(value_field->message_type());
 }
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_map_field.cc b/src/google/protobuf/compiler/objectivec/objectivec_map_field.cc
index 746224ff86..c1b1f53b14 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_map_field.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_map_field.cc
@@ -153,7 +153,7 @@ void MapFieldGenerator::FinishInitialization(void) {
   // Use the array_comment support in RepeatedFieldGenerator to output what the
   // values in the map are.
   const FieldDescriptor* value_descriptor =
-      descriptor_->message_type()->FindFieldByName("value");
+      descriptor_->message_type()->map_value();
   if (GetObjectiveCType(value_descriptor) == OBJECTIVECTYPE_ENUM) {
     variables_["array_comment"] =
         "// |" + variables_["name"] + "| values are |" + value_field_generator_->variable("storage_type") + "|\n";
@@ -164,7 +164,7 @@ void MapFieldGenerator::DetermineForwardDeclarations(
     std::set<std::string>* fwd_decls) const {
   RepeatedFieldGenerator::DetermineForwardDeclarations(fwd_decls);
   const FieldDescriptor* value_descriptor =
-      descriptor_->message_type()->FindFieldByName("value");
+      descriptor_->message_type()->map_value();
   if (GetObjectiveCType(value_descriptor) == OBJECTIVECTYPE_MESSAGE) {
     const std::string& value_storage_type =
         value_field_generator_->variable("storage_type");
@@ -176,7 +176,7 @@ void MapFieldGenerator::DetermineObjectiveCClassDefinitions(
     std::set<std::string>* fwd_decls) const {
   // Class name is already in "storage_type".
   const FieldDescriptor* value_descriptor =
-      descriptor_->message_type()->FindFieldByName("value");
+      descriptor_->message_type()->map_value();
   if (GetObjectiveCType(value_descriptor) == OBJECTIVECTYPE_MESSAGE) {
     fwd_decls->insert(ObjCClassDeclaration(
         value_field_generator_->variable("storage_type")));
diff --git a/src/google/protobuf/compiler/php/php_generator.cc b/src/google/protobuf/compiler/php/php_generator.cc
index 05f8acad87..4b7fda91d4 100644
--- a/src/google/protobuf/compiler/php/php_generator.cc
+++ b/src/google/protobuf/compiler/php/php_generator.cc
@@ -741,8 +741,8 @@ void GenerateFieldAccessor(const FieldDescriptor* field, const Options& options,
   // Type check.
   if (field->is_map()) {
     const Descriptor* map_entry = field->message_type();
-    const FieldDescriptor* key = map_entry->FindFieldByName("key");
-    const FieldDescriptor* value = map_entry->FindFieldByName("value");
+    const FieldDescriptor* key = map_entry->map_key();
+    const FieldDescriptor* value = map_entry->map_value();
     printer->Print(
         "$arr = GPBUtil::checkMapField($var, "
         "\\Google\\Protobuf\\Internal\\GPBType::^key_type^, "
@@ -889,9 +889,9 @@ void GenerateMessageToPool(const std::string& name_prefix,
     const FieldDescriptor* field = message->field(i);
     if (field->is_map()) {
       const FieldDescriptor* key =
-          field->message_type()->FindFieldByName("key");
+          field->message_type()->map_key();
       const FieldDescriptor* val =
-          field->message_type()->FindFieldByName("value");
+          field->message_type()->map_value();
       printer->Print(
           "->map('^field^', \\Google\\Protobuf\\Internal\\GPBType::^key^, "
           "\\Google\\Protobuf\\Internal\\GPBType::^value^, ^number^^other^)\n",
diff --git a/src/google/protobuf/generated_message_reflection.cc b/src/google/protobuf/generated_message_reflection.cc
index cf7cd852cd..f6de1b5609 100644
--- a/src/google/protobuf/generated_message_reflection.cc
+++ b/src/google/protobuf/generated_message_reflection.cc
@@ -2325,7 +2325,7 @@ bool Reflection::InsertOrLookupMapValue(Message* message,
                                         MapValueRef* val) const {
   USAGE_CHECK(IsMapFieldInApi(field), "InsertOrLookupMapValue",
               "Field is not a map field.");
-  val->SetType(field->message_type()->FindFieldByName("value")->cpp_type());
+  val->SetType(field->message_type()->map_value()->cpp_type());
   return MutableRaw<MapFieldBase>(message, field)
       ->InsertOrLookupMapValue(key, val);
 }
@@ -2335,7 +2335,7 @@ bool Reflection::LookupMapValue(const Message& message,
                                 MapValueConstRef* val) const {
   USAGE_CHECK(IsMapFieldInApi(field), "LookupMapValue",
               "Field is not a map field.");
-  val->SetType(field->message_type()->FindFieldByName("value")->cpp_type());
+  val->SetType(field->message_type()->map_value()->cpp_type());
   return GetRaw<MapFieldBase>(message, field).LookupMapValue(key, val);
 }
 
diff --git a/src/google/protobuf/map_field.h b/src/google/protobuf/map_field.h
index c87d44e5eb..19b73ca2b7 100644
--- a/src/google/protobuf/map_field.h
+++ b/src/google/protobuf/map_field.h
@@ -855,8 +855,8 @@ class PROTOBUF_EXPORT MapIterator {
   MapIterator(Message* message, const FieldDescriptor* field) {
     const Reflection* reflection = message->GetReflection();
     map_ = reflection->MutableMapData(message, field);
-    key_.SetType(field->message_type()->FindFieldByName("key")->cpp_type());
-    value_.SetType(field->message_type()->FindFieldByName("value")->cpp_type());
+    key_.SetType(field->message_type()->map_key()->cpp_type());
+    value_.SetType(field->message_type()->map_value()->cpp_type());
     map_->InitializeIterator(this);
   }
   MapIterator(const MapIterator& other) {
diff --git a/src/google/protobuf/map_test.inc b/src/google/protobuf/map_test.inc
index 733f13beff..ed75c6fec6 100644
--- a/src/google/protobuf/map_test.inc
+++ b/src/google/protobuf/map_test.inc
@@ -1259,21 +1259,21 @@ TEST_F(MapFieldReflectionTest, RegularFields) {
       desc->FindFieldByName("map_int32_foreign_message");
 
   const FieldDescriptor* fd_map_int32_in32_key =
-      fd_map_int32_int32->message_type()->FindFieldByName("key");
+      fd_map_int32_int32->message_type()->map_key();
   const FieldDescriptor* fd_map_int32_in32_value =
-      fd_map_int32_int32->message_type()->FindFieldByName("value");
+      fd_map_int32_int32->message_type()->map_value();
   const FieldDescriptor* fd_map_int32_double_key =
-      fd_map_int32_double->message_type()->FindFieldByName("key");
+      fd_map_int32_double->message_type()->map_key();
   const FieldDescriptor* fd_map_int32_double_value =
-      fd_map_int32_double->message_type()->FindFieldByName("value");
+      fd_map_int32_double->message_type()->map_value();
   const FieldDescriptor* fd_map_string_string_key =
-      fd_map_string_string->message_type()->FindFieldByName("key");
+      fd_map_string_string->message_type()->map_key();
   const FieldDescriptor* fd_map_string_string_value =
-      fd_map_string_string->message_type()->FindFieldByName("value");
+      fd_map_string_string->message_type()->map_value();
   const FieldDescriptor* fd_map_int32_foreign_message_key =
-      fd_map_int32_foreign_message->message_type()->FindFieldByName("key");
+      fd_map_int32_foreign_message->message_type()->map_key();
   const FieldDescriptor* fd_map_int32_foreign_message_value =
-      fd_map_int32_foreign_message->message_type()->FindFieldByName("value");
+      fd_map_int32_foreign_message->message_type()->map_value();
 
   // Get RepeatedPtrField objects for all fields of interest.
   const RepeatedPtrField<Message>& mf_int32_int32 =
@@ -1446,21 +1446,21 @@ TEST_F(MapFieldReflectionTest, RepeatedFieldRefForRegularFields) {
       desc->FindFieldByName("map_int32_foreign_message");
 
   const FieldDescriptor* fd_map_int32_in32_key =
-      fd_map_int32_int32->message_type()->FindFieldByName("key");
+      fd_map_int32_int32->message_type()->map_key();
   const FieldDescriptor* fd_map_int32_in32_value =
-      fd_map_int32_int32->message_type()->FindFieldByName("value");
+      fd_map_int32_int32->message_type()->map_value();
   const FieldDescriptor* fd_map_int32_double_key =
-      fd_map_int32_double->message_type()->FindFieldByName("key");
+      fd_map_int32_double->message_type()->map_key();
   const FieldDescriptor* fd_map_int32_double_value =
-      fd_map_int32_double->message_type()->FindFieldByName("value");
+      fd_map_int32_double->message_type()->map_value();
   const FieldDescriptor* fd_map_string_string_key =
-      fd_map_string_string->message_type()->FindFieldByName("key");
+      fd_map_string_string->message_type()->map_key();
   const FieldDescriptor* fd_map_string_string_value =
-      fd_map_string_string->message_type()->FindFieldByName("value");
+      fd_map_string_string->message_type()->map_value();
   const FieldDescriptor* fd_map_int32_foreign_message_key =
-      fd_map_int32_foreign_message->message_type()->FindFieldByName("key");
+      fd_map_int32_foreign_message->message_type()->map_key();
   const FieldDescriptor* fd_map_int32_foreign_message_value =
-      fd_map_int32_foreign_message->message_type()->FindFieldByName("value");
+      fd_map_int32_foreign_message->message_type()->map_value();
 
   // Get RepeatedFieldRef objects for all fields of interest.
   const RepeatedFieldRef<Message> mf_int32_int32 =
@@ -2038,7 +2038,7 @@ TEST_F(MapFieldReflectionTest, MapSizeWithDuplicatedKey) {
 
     const Reflection* entry_reflection = entry1->GetReflection();
     const FieldDescriptor* key_field =
-        entry1->GetDescriptor()->FindFieldByName("key");
+        entry1->GetDescriptor()->map_key();
     entry_reflection->SetInt32(entry1, key_field, 1);
     entry_reflection->SetInt32(entry2, key_field, 1);
 
@@ -2059,7 +2059,7 @@ TEST_F(MapFieldReflectionTest, MapSizeWithDuplicatedKey) {
 
     const Reflection* entry_reflection = entry1->GetReflection();
     const FieldDescriptor* key_field =
-        entry1->GetDescriptor()->FindFieldByName("key");
+        entry1->GetDescriptor()->map_key();
     entry_reflection->SetInt32(entry1, key_field, 1);
     entry_reflection->SetInt32(entry2, key_field, 1);
 
@@ -2951,7 +2951,7 @@ TEST(GeneratedMapFieldReflectionTest, EmbedProto2Message) {
       UNITTEST::TestMessageMap::descriptor()->FindFieldByName(
           "map_int32_message");
   const FieldDescriptor* value =
-      map_field->message_type()->FindFieldByName("value");
+      map_field->message_type()->map_value();
 
   Message* entry_message =
       message.GetReflection()->AddMessage(&message, map_field);
@@ -2971,9 +2971,9 @@ TEST(GeneratedMapFieldReflectionTest, MergeFromClearMapEntry) {
   const FieldDescriptor* map_field =
       UNITTEST::TestMap::descriptor()->FindFieldByName("map_int32_int32");
   const FieldDescriptor* key =
-      map_field->message_type()->FindFieldByName("key");
+      map_field->message_type()->map_key();
   const FieldDescriptor* value =
-      map_field->message_type()->FindFieldByName("value");
+      map_field->message_type()->map_value();
 
   Message* entry_message1 =
       message.GetReflection()->AddMessage(&message, map_field);
@@ -3005,7 +3005,7 @@ TEST(GeneratedMapFieldReflectionTest, Proto2MapEntryClear) {
   const FieldDescriptor* field_descriptor =
       descriptor->FindFieldByName("known_map_field");
   const FieldDescriptor* value_descriptor =
-      field_descriptor->message_type()->FindFieldByName("value");
+      field_descriptor->message_type()->map_value();
   Message* sub_message =
       message.GetReflection()->AddMessage(&message, field_descriptor);
   EXPECT_EQ(0, sub_message->GetReflection()->GetEnumValue(*sub_message,
@@ -3133,7 +3133,7 @@ TEST_F(MapFieldInDynamicMessageTest, MapEntryReferernceValidAfterSerialize) {
       message.get(), "map_int32_foreign_message", 0);
   const Reflection* map_entry_reflection = map_entry->GetReflection();
   const Descriptor* map_entry_desc = map_entry->GetDescriptor();
-  const FieldDescriptor* value_field = map_entry_desc->FindFieldByName("value");
+  const FieldDescriptor* value_field = map_entry_desc->map_value();
   Message* submsg =
       map_entry_reflection->MutableMessage(map_entry, value_field);
 
@@ -3696,7 +3696,7 @@ TEST(TextFormatMapTest, NoDisableReflectionIterator) {
   // Modify map via the iterator (invalidated in previous implementation.).
   const Reflection* map_entry_reflection = iter->GetReflection();
   const FieldDescriptor* value_field_desc =
-      iter->GetDescriptor()->FindFieldByName("value");
+      iter->GetDescriptor()->map_value();
   map_entry_reflection->SetInt32(&(*iter), value_field_desc, 2);
   GOOGLE_LOG(INFO) << iter->DebugString();
 
diff --git a/src/google/protobuf/util/message_differencer_unittest.cc b/src/google/protobuf/util/message_differencer_unittest.cc
index fbbcd3c8be..2304743346 100644
--- a/src/google/protobuf/util/message_differencer_unittest.cc
+++ b/src/google/protobuf/util/message_differencer_unittest.cc
@@ -3408,7 +3408,7 @@ class LengthMapKeyComparator
     const Reflection* reflection1 = message1.GetReflection();
     const Reflection* reflection2 = message2.GetReflection();
     const FieldDescriptor* key_field =
-        message1.GetDescriptor()->FindFieldByName("key");
+        message1.GetDescriptor()->map_key();
     return reflection1->GetString(message1, key_field).size() ==
            reflection2->GetString(message2, key_field).size();
   }