could error message FieldName be json tag?

[GerryLon]

return github_com_mwitkow_go_proto_validators.FieldError("ProjectName", fmt.Errorf(`value '%v' must not be an empty string`, this.ProjectName))

ProjectName          string   `protobuf:"bytes,3,opt,name=project_name,proto3" json:"project_name,omitempty"`

if error message's FieldName set toproject_name(from json tag) will better.