将golang类型定义为protobuf的.proto文件中其他类型的切片

I want to define a golang type in .proto file. The type is a slice of other type which is defined in .proto file.

I have types as below.

type SomeType struct {
    // few fields
}

type SomeTypes []SomeType

I have SomeType is defined in .proto file as below.

message SomeType {
    //
}

Now I want to define type SomeTypes in .proto file. But I have not found any way to do that. The simplest solution for me is to change type SomeTypes as below:

type SomeTypes struct {
    Content []SomeType
}

Then I can define that in .proto file as

message SomeTypes {
      repeated SomeType Content = 1 [(gogoproto.nullable) = false];
}

But I want to know if there is any solution which does not involve changing the struct SomeTypes

I am using proto2.

Found that there is an issue created in protobuf project: https://github.com/gogo/protobuf/issues/433 so it is confirmed that there is no other way currently.