Method equivalent

bolt/type/Type.cpp:254–263

    : child_{std::move(child)}, parameters_{{TypeParameter(child_)}} {}

bool ArrayType::equivalent(const Type& other) const {
  if (&other == this) {
    return true;
  }
  if (!Type::hasSameTypeId(other)) {
    return false;
  }
  auto& otherArray = other.asArray();
  return child_->equivalent(*otherArray.child_);
}

folly::dynamic ArrayType::serialize() const {
  folly::dynamic obj = folly::dynamic::object;