You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: oneofcheck.go
    path of file: ./repos/kubernetes/vendor/github.com/gogo/protobuf/plugin/oneofcheck
    
    the code of the file until where you have to start completion: // Protocol Buffers for Go with Gadgets
//
// Copyright (c) 2013, The GoGo Authors. All rights reserved.
// http://github.com/gogo/protobuf
//
// Redistribution and use in s
    
func (p *plugin) Generate(file *generator.FileDescriptor) {
	for _, msg := range file.Messages() {
		face := gogoproto.IsFace(file.FileDescriptorProto, msg.DescriptorProto)
		for _, field := range msg.GetField() {
			if field.OneofIndex == nil {
				continue
			}
			if face {
				fmt.Fprintf(os.Stderr, "ERROR: field %v.%v cannot be in a face and oneof\n", generator.CamelCase(*msg.Name), generator.CamelCase(*field.Name))
				os.Exit(1)
			}
			if gogoproto.IsEmbed(field) {
				fmt.Fprintf(os.Stderr, "ERROR: field %v.%v cannot be in an oneof and an embedded field\n", generator.CamelCase(*msg.Name), generator.CamelCase(*field.Name))
				os.Exit(1)
			}
			if !gogoproto.IsNullable(field) {
				fmt.Fprintf(os.Stderr, "ERROR: field %v.%v cannot be in an oneof and a non-nullable field\n", generator.CamelCase(*msg.Name), generator.CamelCase(*field.Name))
				os.Exit(1)
			}
			if gogoproto.IsUnion(file.FileDescriptorProto, msg.DescriptorProto) {
				fmt.Fprintf(os.Stderr, "ERROR: field %v.%v cannot be in an oneof and in an union (deprecated)\n", generator.CamelCase(*msg.Name), generator.CamelCase(*field.Name))
				os.Exit(1)
			}
		}
	}
}