Add a workaround for GCC constexpr bug

This turns the constexpr constructors into templates to silence errors when constexpr isn't valid.  We are also switching to 12.2 for GCC/cmake tests to prevent regressions (9.5 and 13.1 are already tested by GCC/bazel tests).

Fixes #12807

PiperOrigin-RevId: 532258101

.github/workflows/test_cpp.yml

@@ -234,7 +234,7 @@ jobs:
       - name: Run tests
         uses: protocolbuffers/protobuf-ci/docker@v1
         with:
-          image: us-docker.pkg.dev/protobuf-build/containers/test/linux/gcc:13.1-5.4.0-307caa02808127e49720f3e77d6a9f3b3ef5a915
+          image: us-docker.pkg.dev/protobuf-build/containers/test/linux/gcc:12.2-5.4.0-307caa02808127e49720f3e77d6a9f3b3ef5a915
           credentials: ${{ secrets.GAR_SERVICE_ACCOUNT }}
           entrypoint: bash
           command: >-

src/google/protobuf/compiler/cpp/message.cc

@@ -1155,6 +1155,9 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* p) {
         "    ::$proto_ns$::internal::WireFormatLite::$val_wire_type$> "
         "SuperType;\n"
         "  $classname$();\n"
+        // Templatize constexpr constructor as a workaround for a bug in gcc 12
+        // (warning in gcc 13).
+        "  template <typename = void>\n"
         "  explicit PROTOBUF_CONSTEXPR $classname$(\n"
         "      ::$proto_ns$::internal::ConstantInitialized);\n"
         "  explicit $classname$(::$proto_ns$::Arena* arena);\n"
@@ -1248,6 +1251,9 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* p) {
     format("~$classname$() override;\n");
   }
   format(
+      // Templatize constexpr constructor as a workaround for a bug in gcc 12
+      // (warning in gcc 13).
+      "template<typename = void>\n"
       "explicit PROTOBUF_CONSTEXPR "
       "$classname$(::$proto_ns$::internal::ConstantInitialized);\n"
       "\n"
@@ -2449,13 +2455,19 @@ void MessageGenerator::GenerateConstexprConstructor(io::Printer* p) {
   Formatter format(p);
 
   if (IsMapEntryMessage(descriptor_) || !HasImplData(descriptor_, options_)) {
+    // Templatize constexpr constructor as a workaround for a bug in gcc 12
+    // (warning in gcc 13).
     format(
+        "template <typename>\n"
         "PROTOBUF_CONSTEXPR $classname$::$classname$(\n"
         "    ::_pbi::ConstantInitialized) {}\n");
     return;
   }
 
+  // Templatize constexpr constructor as a workaround for a bug in gcc 12
+  // (warning in gcc 13).
   format(
+      "template <typename>\n"
       "PROTOBUF_CONSTEXPR $classname$::$classname$(\n"
       "    ::_pbi::ConstantInitialized)");
 

src/google/protobuf/compiler/plugin.pb.cc

@@ -20,6 +20,7 @@ namespace _pb = ::PROTOBUF_NAMESPACE_ID;
 namespace _pbi = ::PROTOBUF_NAMESPACE_ID::internal;
 PROTOBUF_NAMESPACE_OPEN
 namespace compiler {
+template <typename>
 PROTOBUF_CONSTEXPR Version::Version(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -44,6 +45,7 @@ struct VersionDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 VersionDefaultTypeInternal _Version_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR CodeGeneratorRequest::CodeGeneratorRequest(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -65,6 +67,7 @@ struct CodeGeneratorRequestDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 CodeGeneratorRequestDefaultTypeInternal _CodeGeneratorRequest_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR CodeGeneratorResponse_File::CodeGeneratorResponse_File(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -92,6 +95,7 @@ struct CodeGeneratorResponse_FileDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 CodeGeneratorResponse_FileDefaultTypeInternal _CodeGeneratorResponse_File_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR CodeGeneratorResponse::CodeGeneratorResponse(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}

src/google/protobuf/compiler/plugin.pb.h

@@ -124,6 +124,7 @@ class PROTOC_EXPORT Version final :
  public:
   inline Version() : Version(nullptr) {}
   ~Version() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR Version(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   Version(const Version& from);
@@ -329,6 +330,7 @@ class PROTOC_EXPORT CodeGeneratorRequest final :
  public:
   inline CodeGeneratorRequest() : CodeGeneratorRequest(nullptr) {}
   ~CodeGeneratorRequest() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR CodeGeneratorRequest(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   CodeGeneratorRequest(const CodeGeneratorRequest& from);
@@ -565,6 +567,7 @@ class PROTOC_EXPORT CodeGeneratorResponse_File final :
  public:
   inline CodeGeneratorResponse_File() : CodeGeneratorResponse_File(nullptr) {}
   ~CodeGeneratorResponse_File() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR CodeGeneratorResponse_File(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   CodeGeneratorResponse_File(const CodeGeneratorResponse_File& from);
@@ -793,6 +796,7 @@ class PROTOC_EXPORT CodeGeneratorResponse final :
  public:
   inline CodeGeneratorResponse() : CodeGeneratorResponse(nullptr) {}
   ~CodeGeneratorResponse() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR CodeGeneratorResponse(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   CodeGeneratorResponse(const CodeGeneratorResponse& from);

src/google/protobuf/descriptor.pb.cc

@@ -19,6 +19,7 @@ PROTOBUF_PRAGMA_INIT_SEG
 namespace _pb = ::PROTOBUF_NAMESPACE_ID;
 namespace _pbi = ::PROTOBUF_NAMESPACE_ID::internal;
 PROTOBUF_NAMESPACE_OPEN
+template <typename>
 PROTOBUF_CONSTEXPR FileDescriptorSet::FileDescriptorSet(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_.file_)*/{}
@@ -33,6 +34,7 @@ struct FileDescriptorSetDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 FileDescriptorSetDefaultTypeInternal _FileDescriptorSet_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR FileDescriptorProto::FileDescriptorProto(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -74,6 +76,7 @@ struct FileDescriptorProtoDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 FileDescriptorProtoDefaultTypeInternal _FileDescriptorProto_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR DescriptorProto_ExtensionRange::DescriptorProto_ExtensionRange(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -93,6 +96,7 @@ struct DescriptorProto_ExtensionRangeDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 DescriptorProto_ExtensionRangeDefaultTypeInternal _DescriptorProto_ExtensionRange_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR DescriptorProto_ReservedRange::DescriptorProto_ReservedRange(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -111,6 +115,7 @@ struct DescriptorProto_ReservedRangeDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 DescriptorProto_ReservedRangeDefaultTypeInternal _DescriptorProto_ReservedRange_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR DescriptorProto::DescriptorProto(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -138,6 +143,7 @@ struct DescriptorProtoDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 DescriptorProtoDefaultTypeInternal _DescriptorProto_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR ExtensionRangeOptions_Declaration::ExtensionRangeOptions_Declaration(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -168,6 +174,7 @@ struct ExtensionRangeOptions_DeclarationDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 ExtensionRangeOptions_DeclarationDefaultTypeInternal _ExtensionRangeOptions_Declaration_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR ExtensionRangeOptions::ExtensionRangeOptions(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._extensions_)*/{}
@@ -187,6 +194,7 @@ struct ExtensionRangeOptionsDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 ExtensionRangeOptionsDefaultTypeInternal _ExtensionRangeOptions_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR FieldDescriptorProto::FieldDescriptorProto(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -232,6 +240,7 @@ struct FieldDescriptorProtoDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 FieldDescriptorProtoDefaultTypeInternal _FieldDescriptorProto_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR OneofDescriptorProto::OneofDescriptorProto(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -251,6 +260,7 @@ struct OneofDescriptorProtoDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 OneofDescriptorProtoDefaultTypeInternal _OneofDescriptorProto_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR EnumDescriptorProto_EnumReservedRange::EnumDescriptorProto_EnumReservedRange(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -269,6 +279,7 @@ struct EnumDescriptorProto_EnumReservedRangeDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 EnumDescriptorProto_EnumReservedRangeDefaultTypeInternal _EnumDescriptorProto_EnumReservedRange_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR EnumDescriptorProto::EnumDescriptorProto(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -291,6 +302,7 @@ struct EnumDescriptorProtoDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 EnumDescriptorProtoDefaultTypeInternal _EnumDescriptorProto_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR EnumValueDescriptorProto::EnumValueDescriptorProto(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -312,6 +324,7 @@ struct EnumValueDescriptorProtoDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 EnumValueDescriptorProtoDefaultTypeInternal _EnumValueDescriptorProto_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR ServiceDescriptorProto::ServiceDescriptorProto(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -332,6 +345,7 @@ struct ServiceDescriptorProtoDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 ServiceDescriptorProtoDefaultTypeInternal _ServiceDescriptorProto_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR MethodDescriptorProto::MethodDescriptorProto(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -363,6 +377,7 @@ struct MethodDescriptorProtoDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 MethodDescriptorProtoDefaultTypeInternal _MethodDescriptorProto_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR FileOptions::FileOptions(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._extensions_)*/{}
@@ -439,6 +454,7 @@ struct FileOptionsDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 FileOptionsDefaultTypeInternal _FileOptions_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR MessageOptions::MessageOptions(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._extensions_)*/{}
@@ -465,6 +481,7 @@ struct MessageOptionsDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 MessageOptionsDefaultTypeInternal _MessageOptions_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR FieldOptions::FieldOptions(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._extensions_)*/{}
@@ -503,6 +520,7 @@ struct FieldOptionsDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 FieldOptionsDefaultTypeInternal _FieldOptions_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR OneofOptions::OneofOptions(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._extensions_)*/{}
@@ -518,6 +536,7 @@ struct OneofOptionsDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 OneofOptionsDefaultTypeInternal _OneofOptions_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR EnumOptions::EnumOptions(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._extensions_)*/{}
@@ -540,6 +559,7 @@ struct EnumOptionsDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 EnumOptionsDefaultTypeInternal _EnumOptions_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR EnumValueOptions::EnumValueOptions(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._extensions_)*/{}
@@ -558,6 +578,7 @@ struct EnumValueOptionsDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 EnumValueOptionsDefaultTypeInternal _EnumValueOptions_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR ServiceOptions::ServiceOptions(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._extensions_)*/{}
@@ -576,6 +597,7 @@ struct ServiceOptionsDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 ServiceOptionsDefaultTypeInternal _ServiceOptions_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR MethodOptions::MethodOptions(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._extensions_)*/{}
@@ -596,6 +618,7 @@ struct MethodOptionsDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 MethodOptionsDefaultTypeInternal _MethodOptions_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR UninterpretedOption_NamePart::UninterpretedOption_NamePart(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -616,6 +639,7 @@ struct UninterpretedOption_NamePartDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 UninterpretedOption_NamePartDefaultTypeInternal _UninterpretedOption_NamePart_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR UninterpretedOption::UninterpretedOption(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -649,6 +673,7 @@ struct UninterpretedOptionDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 UninterpretedOptionDefaultTypeInternal _UninterpretedOption_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR SourceCodeInfo_Location::SourceCodeInfo_Location(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -678,6 +703,7 @@ struct SourceCodeInfo_LocationDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 SourceCodeInfo_LocationDefaultTypeInternal _SourceCodeInfo_Location_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR SourceCodeInfo::SourceCodeInfo(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_.location_)*/{}
@@ -692,6 +718,7 @@ struct SourceCodeInfoDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 SourceCodeInfoDefaultTypeInternal _SourceCodeInfo_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_._has_bits_)*/{}
@@ -719,6 +746,7 @@ struct GeneratedCodeInfo_AnnotationDefaultTypeInternal {
 
 PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
     PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 GeneratedCodeInfo_AnnotationDefaultTypeInternal _GeneratedCodeInfo_Annotation_default_instance_;
+template <typename>
 PROTOBUF_CONSTEXPR GeneratedCodeInfo::GeneratedCodeInfo(
     ::_pbi::ConstantInitialized): _impl_{
     /*decltype(_impl_.annotation_)*/{}

src/google/protobuf/descriptor.pb.h

@@ -517,6 +517,7 @@ class PROTOBUF_EXPORT FileDescriptorSet final :
  public:
   inline FileDescriptorSet() : FileDescriptorSet(nullptr) {}
   ~FileDescriptorSet() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR FileDescriptorSet(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   FileDescriptorSet(const FileDescriptorSet& from);
@@ -681,6 +682,7 @@ class PROTOBUF_EXPORT FileDescriptorProto final :
  public:
   inline FileDescriptorProto() : FileDescriptorProto(nullptr) {}
   ~FileDescriptorProto() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR FileDescriptorProto(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   FileDescriptorProto(const FileDescriptorProto& from);
@@ -1112,6 +1114,7 @@ class PROTOBUF_EXPORT DescriptorProto_ExtensionRange final :
  public:
   inline DescriptorProto_ExtensionRange() : DescriptorProto_ExtensionRange(nullptr) {}
   ~DescriptorProto_ExtensionRange() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR DescriptorProto_ExtensionRange(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   DescriptorProto_ExtensionRange(const DescriptorProto_ExtensionRange& from);
@@ -1297,6 +1300,7 @@ class PROTOBUF_EXPORT DescriptorProto_ReservedRange final :
  public:
   inline DescriptorProto_ReservedRange() : DescriptorProto_ReservedRange(nullptr) {}
   ~DescriptorProto_ReservedRange() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR DescriptorProto_ReservedRange(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   DescriptorProto_ReservedRange(const DescriptorProto_ReservedRange& from);
@@ -1466,6 +1470,7 @@ class PROTOBUF_EXPORT DescriptorProto final :
  public:
   inline DescriptorProto() : DescriptorProto(nullptr) {}
   ~DescriptorProto() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR DescriptorProto(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   DescriptorProto(const DescriptorProto& from);
@@ -1837,6 +1842,7 @@ class PROTOBUF_EXPORT ExtensionRangeOptions_Declaration final :
  public:
   inline ExtensionRangeOptions_Declaration() : ExtensionRangeOptions_Declaration(nullptr) {}
   ~ExtensionRangeOptions_Declaration() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR ExtensionRangeOptions_Declaration(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   ExtensionRangeOptions_Declaration(const ExtensionRangeOptions_Declaration& from);
@@ -2078,6 +2084,7 @@ class PROTOBUF_EXPORT ExtensionRangeOptions final :
  public:
   inline ExtensionRangeOptions() : ExtensionRangeOptions(nullptr) {}
   ~ExtensionRangeOptions() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR ExtensionRangeOptions(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   ExtensionRangeOptions(const ExtensionRangeOptions& from);
@@ -2453,6 +2460,7 @@ class PROTOBUF_EXPORT FieldDescriptorProto final :
  public:
   inline FieldDescriptorProto() : FieldDescriptorProto(nullptr) {}
   ~FieldDescriptorProto() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR FieldDescriptorProto(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   FieldDescriptorProto(const FieldDescriptorProto& from);
@@ -2849,6 +2857,7 @@ class PROTOBUF_EXPORT OneofDescriptorProto final :
  public:
   inline OneofDescriptorProto() : OneofDescriptorProto(nullptr) {}
   ~OneofDescriptorProto() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR OneofDescriptorProto(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   OneofDescriptorProto(const OneofDescriptorProto& from);
@@ -3031,6 +3040,7 @@ class PROTOBUF_EXPORT EnumDescriptorProto_EnumReservedRange final :
  public:
   inline EnumDescriptorProto_EnumReservedRange() : EnumDescriptorProto_EnumReservedRange(nullptr) {}
   ~EnumDescriptorProto_EnumReservedRange() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR EnumDescriptorProto_EnumReservedRange(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   EnumDescriptorProto_EnumReservedRange(const EnumDescriptorProto_EnumReservedRange& from);
@@ -3200,6 +3210,7 @@ class PROTOBUF_EXPORT EnumDescriptorProto final :
  public:
   inline EnumDescriptorProto() : EnumDescriptorProto(nullptr) {}
   ~EnumDescriptorProto() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR EnumDescriptorProto(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   EnumDescriptorProto(const EnumDescriptorProto& from);
@@ -3460,6 +3471,7 @@ class PROTOBUF_EXPORT EnumValueDescriptorProto final :
  public:
   inline EnumValueDescriptorProto() : EnumValueDescriptorProto(nullptr) {}
   ~EnumValueDescriptorProto() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR EnumValueDescriptorProto(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   EnumValueDescriptorProto(const EnumValueDescriptorProto& from);
@@ -3655,6 +3667,7 @@ class PROTOBUF_EXPORT ServiceDescriptorProto final :
  public:
   inline ServiceDescriptorProto() : ServiceDescriptorProto(nullptr) {}
   ~ServiceDescriptorProto() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR ServiceDescriptorProto(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   ServiceDescriptorProto(const ServiceDescriptorProto& from);
@@ -3859,6 +3872,7 @@ class PROTOBUF_EXPORT MethodDescriptorProto final :
  public:
   inline MethodDescriptorProto() : MethodDescriptorProto(nullptr) {}
   ~MethodDescriptorProto() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR MethodDescriptorProto(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   MethodDescriptorProto(const MethodDescriptorProto& from);
@@ -4113,6 +4127,7 @@ class PROTOBUF_EXPORT FileOptions final :
  public:
   inline FileOptions() : FileOptions(nullptr) {}
   ~FileOptions() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR FileOptions(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   FileOptions(const FileOptions& from);
@@ -4812,6 +4827,7 @@ class PROTOBUF_EXPORT MessageOptions final :
  public:
   inline MessageOptions() : MessageOptions(nullptr) {}
   ~MessageOptions() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR MessageOptions(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   MessageOptions(const MessageOptions& from);
@@ -5195,6 +5211,7 @@ class PROTOBUF_EXPORT FieldOptions final :
  public:
   inline FieldOptions() : FieldOptions(nullptr) {}
   ~FieldOptions() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR FieldOptions(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   FieldOptions(const FieldOptions& from);
@@ -5757,6 +5774,7 @@ class PROTOBUF_EXPORT OneofOptions final :
  public:
   inline OneofOptions() : OneofOptions(nullptr) {}
   ~OneofOptions() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR OneofOptions(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   OneofOptions(const OneofOptions& from);
@@ -6074,6 +6092,7 @@ class PROTOBUF_EXPORT EnumOptions final :
  public:
   inline EnumOptions() : EnumOptions(nullptr) {}
   ~EnumOptions() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR EnumOptions(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   EnumOptions(const EnumOptions& from);
@@ -6431,6 +6450,7 @@ class PROTOBUF_EXPORT EnumValueOptions final :
  public:
   inline EnumValueOptions() : EnumValueOptions(nullptr) {}
   ~EnumValueOptions() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR EnumValueOptions(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   EnumValueOptions(const EnumValueOptions& from);
@@ -6762,6 +6782,7 @@ class PROTOBUF_EXPORT ServiceOptions final :
  public:
   inline ServiceOptions() : ServiceOptions(nullptr) {}
   ~ServiceOptions() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR ServiceOptions(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   ServiceOptions(const ServiceOptions& from);
@@ -7093,6 +7114,7 @@ class PROTOBUF_EXPORT MethodOptions final :
  public:
   inline MethodOptions() : MethodOptions(nullptr) {}
   ~MethodOptions() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR MethodOptions(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   MethodOptions(const MethodOptions& from);
@@ -7458,6 +7480,7 @@ class PROTOBUF_EXPORT UninterpretedOption_NamePart final :
  public:
   inline UninterpretedOption_NamePart() : UninterpretedOption_NamePart(nullptr) {}
   ~UninterpretedOption_NamePart() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR UninterpretedOption_NamePart(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   UninterpretedOption_NamePart(const UninterpretedOption_NamePart& from);
@@ -7640,6 +7663,7 @@ class PROTOBUF_EXPORT UninterpretedOption final :
  public:
   inline UninterpretedOption() : UninterpretedOption(nullptr) {}
   ~UninterpretedOption() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR UninterpretedOption(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   UninterpretedOption(const UninterpretedOption& from);
@@ -7915,6 +7939,7 @@ class PROTOBUF_EXPORT SourceCodeInfo_Location final :
  public:
   inline SourceCodeInfo_Location() : SourceCodeInfo_Location(nullptr) {}
   ~SourceCodeInfo_Location() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR SourceCodeInfo_Location(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   SourceCodeInfo_Location(const SourceCodeInfo_Location& from);
@@ -8182,6 +8207,7 @@ class PROTOBUF_EXPORT SourceCodeInfo final :
  public:
   inline SourceCodeInfo() : SourceCodeInfo(nullptr) {}
   ~SourceCodeInfo() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR SourceCodeInfo(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   SourceCodeInfo(const SourceCodeInfo& from);
@@ -8348,6 +8374,7 @@ class PROTOBUF_EXPORT GeneratedCodeInfo_Annotation final :
  public:
   inline GeneratedCodeInfo_Annotation() : GeneratedCodeInfo_Annotation(nullptr) {}
   ~GeneratedCodeInfo_Annotation() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR GeneratedCodeInfo_Annotation(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   GeneratedCodeInfo_Annotation(const GeneratedCodeInfo_Annotation& from);
@@ -8597,6 +8624,7 @@ class PROTOBUF_EXPORT GeneratedCodeInfo final :
  public:
   inline GeneratedCodeInfo() : GeneratedCodeInfo(nullptr) {}
   ~GeneratedCodeInfo() override;
+  template<typename = void>
   explicit PROTOBUF_CONSTEXPR GeneratedCodeInfo(::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized);
 
   GeneratedCodeInfo(const GeneratedCodeInfo& from);