const google.golang.org/protobuf/reflect/protoreflect.Optional

14 uses

	google.golang.org/protobuf/reflect/protoreflect (current package)
		proto.go#L199: 	Optional Cardinality = 1 // appears zero or one times
		proto.go#L207: 	case Optional, Required, Repeated:
		proto.go#L217: 	case Optional:
		proto.go#L231: 	case Optional:

	google.golang.org/protobuf/reflect/protodesc
		desc_validate.go#L155: 				if f.Cardinality() != protoreflect.Optional {
		desc_validate.go#L206: 				if f.Cardinality() != protoreflect.Optional {
		desc_validate.go#L298: 	return (fd.Kind() == 0 || fd.Kind() == protoreflect.MessageKind) && fd.Cardinality() == protoreflect.Optional
		desc_validate.go#L355: 	case kf.Name() != genid.MapEntry_Key_field_name || kf.Number() != genid.MapEntry_Key_field_number || kf.Cardinality() != protoreflect.Optional || kf.ContainingOneof() != nil || kf.HasDefault():
		desc_validate.go#L357: 	case vf.Name() != genid.MapEntry_Value_field_name || vf.Number() != genid.MapEntry_Value_field_number || vf.Cardinality() != protoreflect.Optional || vf.ContainingOneof() != nil || vf.HasDefault():

	google.golang.org/protobuf/encoding/protojson
		encode.go#L154: 	fd.L1.Cardinality = protoreflect.Optional

	google.golang.org/protobuf/internal/encoding/tag
		tag.go#L47: 			f.L1.Cardinality = protoreflect.Optional
		tag.go#L163: 	case protoreflect.Optional:

	google.golang.org/protobuf/internal/filedesc
		desc.go#L279: 	return (fd.L0.ParentFile.L1.Syntax == protoreflect.Proto2 && fd.L1.Cardinality == protoreflect.Optional && fd.L1.ContainingOneof == nil) || fd.L1.IsProto3Optional
		desc.go#L392: 	return (xd.L0.ParentFile.L1.Syntax == protoreflect.Proto2 && xd.L1.Cardinality == protoreflect.Optional) || xd.lazyInit().IsProto3Optional