Protoc is not generating any validators.

[FrontMage]

protoc \
--go_out=plugins=grpc:./lib/protos/ \
--proto_path=/Users/frontmage/go/src \
--proto_path=/Users/frontmage/go/src/github.com/google/protobuf/src \
--proto_path=./protos/common/ \
--proto_path=./protos/server/ \
--govalidators_out=./lib/protos \
./protos/common/*.proto \
./protos/server/*.proto 

I'm using protoc to generate validators for my proto file, but the validator function is just return nil.

message LoginReq {
    string login_id = 1 [(validator.field) = {msg_exists : true}];
}

func (this *LoginReq) Validate() error {
         return nil
}

The protoc command shows no errors, so how to properly generate validators?

[FrontMage]

It seems that only pointer type will be checked with msg_exists, closing it.