compilation_unit {
  declarations {
    choice {
      alternatives {
        signature {
          fields {
            primitive_operator {
              arguments {
                intrinsic {
                  argument {
                    fields {
                      primitive_operator {
                        arguments {
                          identifier {
                          }
                        }
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}
