// __ _____ _____ _____
// __| | __| | | | JSON for Modern C++ (supporting code)
// | | |__ | | | | | | version 3.11.3
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013 - 2025 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT

#include "doctest_compatibility.h"

// disable -Wnoexcept due to class Evil
DOCTEST_GCC_SUPPRESS_WARNING_PUSH
DOCTEST_GCC_SUPPRESS_WARNING("-Wnoexcept")

// skip tests if JSON_DisableEnumSerialization=ON (#4384)
#if defined(JSON_DISABLE_ENUM_SERIALIZATION) && (JSON_DISABLE_ENUM_SERIALIZATION == 1)
 #define SKIP_TESTS_FOR_ENUM_SERIALIZATION
#endif

#include <nlohmann/json.hpp>
using nlohmann::json;
#ifdef JSON_TEST_NO_GLOBAL_UDLS
 using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
#endif

#include <map>
#include <memory>
#include <string>
#include <utility>

namespace udt
{
enum class country
{
 china,
 france,
 russia
};

struct age
{
 int m_val;
 age(int rhs = 0) : m_val(rhs) {}
};

struct name
{
 std::string m_val;
 name(std::string rhs = "") : m_val(std::move(rhs)) {}
};

struct address
{
 std::string m_val;
 address(std::string rhs = "") : m_val(std::move(rhs)) {}
};

struct person
{
 age m_age{}; // NOLINT(readability-redundant-member-init)
 name m_name{}; // NOLINT(readability-redundant-member-init)
 country m_country{}; // NOLINT(readability-redundant-member-init)
 person() = default;
 person(const age& a, name n, const country& c) : m_age(a), m_name(std::move(n)), m_country(c) {}
};

struct contact
{
 person m_person{}; // NOLINT(readability-redundant-member-init)
 address m_address{}; // NOLINT(readability-redundant-member-init)
 contact() = default;
 contact(person p, address a) : m_person(std::move(p)), m_address(std::move(a)) {}
};

enum class book_id : std::uint64_t;

struct contact_book
{
 name m_book_name{}; // NOLINT(readability-redundant-member-init)
 book_id m_book_id{};
 std::vector<contact> m_contacts{}; // NOLINT(readability-redundant-member-init)
 contact_book() = default;
 contact_book(name n, book_id i, std::vector<contact> c) : m_book_name(std::move(n)), m_book_id(i), m_contacts(std::move(c)) {}
};
} // namespace udt

// to_json methods
namespace udt
{
// templates because of the custom_json tests (see below)
template <typename BasicJsonType>
static void to_json(BasicJsonType& j, age a)
{
 j = a.m_val;
}

template <typename BasicJsonType>
static void to_json(BasicJsonType& j, const name& n)
{
 j = n.m_val;
}

template <typename BasicJsonType>
static void to_json(BasicJsonType& j, country c)
{
 switch (c)
 {
 case country::china:
 j = "中华人民共和国";
 return;
 case country::france:
 j = "France";
 return;
 case country::russia:
 j = "Российская Федерация";
 return;
 default:
 break;
 }
}

template <typename BasicJsonType>
static void to_json(BasicJsonType& j, const person& p)
{
 j = BasicJsonType{{"age", p.m_age}, {"name", p.m_name}, {"country", p.m_country}};
}

static void to_json(nlohmann::json& j, const address& a)
{
 j = a.m_val;
}

static void to_json(nlohmann::json& j, const contact& c)
{
 j = json{{"person", c.m_person}, {"address", c.m_address}};
}

static void to_json(nlohmann::json& j, const contact_book& cb)
{
 j = json{{"name", cb.m_book_name},
#ifndef SKIP_TESTS_FOR_ENUM_SERIALIZATION
 {"id", cb.m_book_id},
#endif
 {"contacts", cb.m_contacts}};
}

// operators
static bool operator==(age lhs, age rhs)
{
 return lhs.m_val == rhs.m_val;
}

static bool operator==(const address& lhs, const address& rhs)
{
 return lhs.m_val == rhs.m_val;
}

static bool operator==(const name& lhs, const name& rhs)
{
 return lhs.m_val == rhs.m_val;
}

static bool operator==(const person& lhs, const person& rhs)
{
 return std::tie(lhs.m_name, lhs.m_age) == std::tie(rhs.m_name, rhs.m_age);
}

static bool operator==(const contact& lhs, const contact& rhs)
{
 return std::tie(lhs.m_person, lhs.m_address) ==
 std::tie(rhs.m_person, rhs.m_address);
}

static bool operator==(const contact_book& lhs, const contact_book& rhs)
{
 return std::tie(lhs.m_book_name, lhs.m_book_id, lhs.m_contacts) ==
 std::tie(rhs.m_book_name, rhs.m_book_id, rhs.m_contacts);
}
} // namespace udt

// from_json methods
namespace udt
{
template <typename BasicJsonType>
static void from_json(const BasicJsonType& j, age& a)
{
 a.m_val = j.template get<int>();
}

template <typename BasicJsonType>
static void from_json(const BasicJsonType& j, name& n)
{
 n.m_val = j.template get<std::string>();
}

template <typename BasicJsonType>
static void from_json(const BasicJsonType& j, country& c)
{
 const auto str = j.template get<std::string>();
 const std::map<std::string, country> m =
 {
 {"中华人民共和国", country::china},
 {"France", country::france},
 {"Российская Федерация", country::russia}
 };

 const auto it = m.find(str);
 // TODO(nlohmann) test exceptions
 c = it->second;
}

template <typename BasicJsonType>
static void from_json(const BasicJsonType& j, person& p)
{
 p.m_age = j["age"].template get<age>();
 p.m_name = j["name"].template get<name>();
 p.m_country = j["country"].template get<country>();
}

static void from_json(const nlohmann::json& j, address& a)
{
 a.m_val = j.get<std::string>();
}

static void from_json(const nlohmann::json& j, contact& c)
{
 c.m_person = j["person"].get<person>();
 c.m_address = j["address"].get<address>();
}

static void from_json(const nlohmann::json& j, contact_book& cb)
{
 cb.m_book_name = j["name"].get<name>();
#ifndef SKIP_TESTS_FOR_ENUM_SERIALIZATION
 cb.m_book_id = j["id"].get<book_id>();
#endif
 cb.m_contacts = j["contacts"].get<std::vector<contact>>();
}
} // namespace udt

TEST_CASE("basic usage" * doctest::test_suite("udt"))
{

 // a bit narcissistic maybe :) ?
 const udt::age a
 {
 23
 };
 const udt::name n{"theo"};
 const udt::country c{udt::country::france};
 const udt::person sfinae_addict{a, n, c};
 const udt::person senior_programmer{{42}, {"王芳"}, udt::country::china};
 const udt::address addr{"Paris"};
 const udt::contact cpp_programmer{sfinae_addict, addr};
 const udt::book_id large_id{static_cast<udt::book_id>(static_cast<std::uint64_t>(1) << 63)}; // verify large unsigned enums are handled correctly
 const udt::contact_book book{{"C++"}, static_cast<udt::book_id>(42u), {cpp_programmer, {senior_programmer, addr}}};

 SECTION("conversion to json via free-functions")
 {
 CHECK(json(a) == json(23));
 CHECK(json(n) == json("theo"));
 CHECK(json(c) == json("France"));
 CHECK(json(sfinae_addict) == R"({"name":"theo", "age":23, "country":"France"})"_json);
 CHECK(json("Paris") == json(addr));
 CHECK(json(cpp_programmer) ==
 R"({"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"})"_json);
#ifndef SKIP_TESTS_FOR_ENUM_SERIALIZATION
 CHECK(json(large_id) == json(static_cast<std::uint64_t>(1) << 63));
 CHECK(json(large_id) > 0u);
 CHECK(to_string(json(large_id)) == "9223372036854775808");
 CHECK(json(large_id).is_number_unsigned());
#endif

#ifndef SKIP_TESTS_FOR_ENUM_SERIALIZATION
 CHECK(
 json(book) ==
 R"({"name":"C++", "id":42, "contacts" : [{"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"}, {"person" : {"age":42, "country":"中华人民共和国", "name":"王芳"}, "address":"Paris"}]})"_json);
#else
 CHECK(
 json(book) ==
 R"({"name":"C++", "contacts" : [{"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"}, {"person" : {"age":42, "country":"中华人民共和国", "name":"王芳"}, "address":"Paris"}]})"_json);
#endif

 }

 SECTION("conversion from json via free-functions")
 {
 const auto big_json =
 R"({"name":"C++", "id":42, "contacts" : [{"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"}, {"person" : {"age":42, "country":"中华人民共和国", "name":"王芳"}, "address":"Paris"}]})"_json;
 SECTION("via explicit calls to get")
 {
 const auto parsed_book = big_json.get<udt::contact_book>();
 const auto book_name = big_json["name"].get<udt::name>();
#ifndef SKIP_TESTS_FOR_ENUM_SERIALIZATION
 const auto book_id = big_json["id"].get<udt::book_id>();
#endif
 const auto contacts =
 big_json["contacts"].get<std::vector<udt::contact>>();
 const auto contact_json = big_json["contacts"].at(0);
 const auto contact = contact_json.get<udt::contact>();
 const auto person = contact_json["person"].get<udt::person>();
 const auto address = contact_json["address"].get<udt::address>();
 const auto age = contact_json["person"]["age"].get<udt::age>();
 const auto country =
 contact_json["person"]["country"].get<udt::country>();
 const auto name = contact_json["person"]["name"].get<udt::name>();

 CHECK(age == a);
 CHECK(name == n);
 CHECK(country == c);
 CHECK(address == addr);
 CHECK(person == sfinae_addict);
 CHECK(contact == cpp_programmer);
 CHECK(contacts == book.m_contacts);
 CHECK(book_name == udt::name{"C++"});
#ifndef SKIP_TESTS_FOR_ENUM_SERIALIZATION
 CHECK(book_id == book.m_book_id);
 CHECK(book == parsed_book);
#endif
 }

 SECTION("via explicit calls to get_to")
 {
 udt::person person;
 udt::name name;

 json person_json = big_json["contacts"][0]["person"];
 CHECK(person_json.get_to(person) == sfinae_addict);

 // correct reference gets returned
 person_json["name"].get_to(name).m_val = "new name";
 CHECK(name.m_val == "new name");
 }

#if JSON_USE_IMPLICIT_CONVERSIONS
 SECTION("implicit conversions")
 {
 const udt::contact_book parsed_book = big_json;
 const udt::name book_name = big_json["name"];
#ifndef SKIP_TESTS_FOR_ENUM_SERIALIZATION
 const udt::book_id book_id = big_json["id"];
#endif
 const std::vector<udt::contact> contacts = big_json["contacts"];
 const auto contact_json = big_json["contacts"].at(0);
 const udt::contact contact = contact_json;
 const udt::person person = contact_json["person"];
 const udt::address address = contact_json["address"];
 const udt::age age = contact_json["person"]["age"];
 const udt::country country = contact_json["person"]["country"];
 const udt::name name = contact_json["person"]["name"];

 CHECK(age == a);
 CHECK(name == n);
 CHECK(country == c);
 CHECK(address == addr);
 CHECK(person == sfinae_addict);
 CHECK(contact == cpp_programmer);
 CHECK(contacts == book.m_contacts);
 CHECK(book_name == udt::name{"C++"});
#ifndef SKIP_TESTS_FOR_ENUM_SERIALIZATION
 CHECK(book_id == static_cast<udt::book_id>(42u));
 CHECK(book == parsed_book);
#endif
 }
#endif
 }
}

namespace udt
{
struct legacy_type
{
 std::string number{}; // NOLINT(readability-redundant-member-init)
 legacy_type() = default;
 legacy_type(std::string n) : number(std::move(n)) {}
};
} // namespace udt

namespace nlohmann
{
template <typename T>
struct adl_serializer<std::shared_ptr<T>>
{
 static void to_json(json& j, const std::shared_ptr<T>& opt)
 {
 if (opt)
 {
 j = *opt;
 }
 else
 {
 j = nullptr;
 }
 }

 static void from_json(const json& j, std::shared_ptr<T>& opt)
 {
 if (j.is_null())
 {
 opt = nullptr;
 }
 else
 {
 opt.reset(new T(j.get<T>())); // NOLINT(cppcoreguidelines-owning-memory)
 }
 }
};

template <>
struct adl_serializer<udt::legacy_type>
{
 static void to_json(json& j, const udt::legacy_type& l)
 {
 j = std::stoi(l.number);
 }

 static void from_json(const json& j, udt::legacy_type& l)
 {
 l.number = std::to_string(j.get<int>());
 }
};
} // namespace nlohmann

TEST_CASE("adl_serializer specialization" * doctest::test_suite("udt"))
{
 SECTION("partial specialization")
 {
 SECTION("to_json")
 {
 std::shared_ptr<udt::person> optPerson;

 json j = optPerson;
 CHECK(j.is_null());

 optPerson.reset(new udt::person{{42}, {"John Doe"}, udt::country::russia}); // NOLINT(cppcoreguidelines-owning-memory,modernize-make-shared)
 j = optPerson;
 CHECK_FALSE(j.is_null());

 CHECK(j.get<udt::person>() == *optPerson);
 }

 SECTION("from_json")
 {
 auto person = udt::person{{42}, {"John Doe"}, udt::country::russia};
 json j = person;

 auto optPerson = j.get<std::shared_ptr<udt::person>>();
 REQUIRE(optPerson);
 CHECK(*optPerson == person);

 j = nullptr;
 optPerson = j.get<std::shared_ptr<udt::person>>();
 CHECK(!optPerson);
 }
 }

 SECTION("total specialization")
 {
 SECTION("to_json")
 {
 udt::legacy_type const lt{"4242"};

 json const j = lt;
 CHECK(j.get<int>() == 4242);
 }

 SECTION("from_json")
 {
 json const j = 4242;
 auto lt = j.get<udt::legacy_type>();
 CHECK(lt.number == "4242");
 }
 }
}

namespace nlohmann
{
template <>
struct adl_serializer<std::vector<float>>
{
 using type = std::vector<float>;
 static void to_json(json& j, const type& /*type*/)
 {
 j = "hijacked!";
 }

 static void from_json(const json& /*unnamed*/, type& opt)
 {
 opt = {42.0, 42.0, 42.0};
 }

 // preferred version
 static type from_json(const json& /*unnamed*/)
 {
 return {4.0, 5.0, 6.0};
 }
};
} // namespace nlohmann

TEST_CASE("even supported types can be specialized" * doctest::test_suite("udt"))
{
 json const j = std::vector<float> {1.0, 2.0, 3.0};
 CHECK(j.dump() == R"("hijacked!")");
 auto f = j.get<std::vector<float>>();
 // the single argument from_json method is preferred
 CHECK((f == std::vector<float> {4.0, 5.0, 6.0}));
}

namespace nlohmann
{
template <typename T>
struct adl_serializer<std::unique_ptr<T>>
{
 static void to_json(json& j, const std::unique_ptr<T>& opt)
 {
 if (opt)
 {
 j = *opt;
 }
 else
 {
 j = nullptr;
 }
 }

 // this is the overload needed for non-copyable types,
 static std::unique_ptr<T> from_json(const json& j)
 {
 if (j.is_null())
 {
 return nullptr;
 }

 return std::unique_ptr<T>(new T(j.get<T>()));
 }
};
} // namespace nlohmann

TEST_CASE("Non-copyable types" * doctest::test_suite("udt"))
{
 SECTION("to_json")
 {
 std::unique_ptr<udt::person> optPerson;

 json j = optPerson;
 CHECK(j.is_null());

 optPerson.reset(new udt::person{{42}, {"John Doe"}, udt::country::russia}); // NOLINT(cppcoreguidelines-owning-memory,modernize-make-unique)
 j = optPerson;
 CHECK_FALSE(j.is_null());

 CHECK(j.get<udt::person>() == *optPerson);
 }

 SECTION("from_json")
 {
 auto person = udt::person{{42}, {"John Doe"}, udt::country::russia};
 json j = person;

 auto optPerson = j.get<std::unique_ptr<udt::person>>();
 REQUIRE(optPerson);
 CHECK(*optPerson == person);

 j = nullptr;
 optPerson = j.get<std::unique_ptr<udt::person>>();
 CHECK(!optPerson);
 }
}

// custom serializer - advanced usage
// pack structs that are pod-types (but not scalar types)
// relies on adl for any other type
template <typename T, typename = void>
struct pod_serializer
{
 // use adl for non-pods, or scalar types
 template <
 typename BasicJsonType, typename U = T,
 typename std::enable_if <
 !(std::is_pod<U>::value && std::is_class<U>::value), int >::type = 0 >
 static void from_json(const BasicJsonType& j, U& t)
 {
 using nlohmann::from_json;
 from_json(j, t);
 }

 // special behaviour for pods
 template < typename BasicJsonType, typename U = T,
 typename std::enable_if <
 std::is_pod<U>::value && std::is_class<U>::value, int >::type = 0 >
 static void from_json(const BasicJsonType& j, U& t)
 {
 std::uint64_t value = 0;
 // The following block is no longer relevant in this serializer, make another one that shows the issue
 // the problem arises only when one from_json method is defined without any constraint
 //
 // Why cannot we simply use: j.get<std::uint64_t>() ?
 // Well, with the current experiment, the get method looks for a from_json
 // function, which we are currently defining!
 // This would end up in a stack overflow. Calling nlohmann::from_json is a
 // workaround (is it?).
 // I shall find a good way to avoid this once all constructors are converted
 // to free methods
 //
 // In short, constructing a json by constructor calls to_json
 // calling get calls from_json, for now, we cannot do this in custom
 // serializers
 nlohmann::from_json(j, value);
 auto* bytes = static_cast<char*>(static_cast<void*>(&value)); // NOLINT(bugprone-casting-through-void)
 std::memcpy(&t, bytes, sizeof(value));
 }

 template <
 typename BasicJsonType, typename U = T,
 typename std::enable_if <
 !(std::is_pod<U>::value && std::is_class<U>::value), int >::type = 0 >
 static void to_json(BasicJsonType& j, const T& t)
 {
 using nlohmann::to_json;
 to_json(j, t);
 }

 template < typename BasicJsonType, typename U = T,
 typename std::enable_if <
 std::is_pod<U>::value && std::is_class<U>::value, int >::type = 0 >
 static void to_json(BasicJsonType& j, const T& t) noexcept
 {
 const auto* bytes = static_cast< const unsigned char*>(static_cast<const void*>(&t)); // NOLINT(bugprone-casting-through-void)
 std::uint64_t value = 0;
 std::memcpy(&value, bytes, sizeof(value));
 nlohmann::to_json(j, value);
 }
};

namespace udt
{
struct small_pod
{
 int begin;
 char middle;
 short end;
};

struct non_pod
{
 std::string s{}; // NOLINT(readability-redundant-member-init)
 non_pod() = default;
 non_pod(std::string S) : s(std::move(S)) {}
};

template <typename BasicJsonType>
static void to_json(BasicJsonType& j, const non_pod& np)
{
 j = np.s;
}

template <typename BasicJsonType>
static void from_json(const BasicJsonType& j, non_pod& np)
{
 np.s = j.template get<std::string>();
}

static bool operator==(small_pod lhs, small_pod rhs) noexcept
{
 return std::tie(lhs.begin, lhs.middle, lhs.end) ==
 std::tie(rhs.begin, rhs.middle, rhs.end);
}

static bool operator==(const non_pod& lhs, const non_pod& rhs) noexcept
{
 return lhs.s == rhs.s;
}

static std::ostream& operator<<(std::ostream& os, small_pod l)
{
 return os << "begin: " << l.begin << ", middle: " << l.middle << ", end: " << l.end;
}
} // namespace udt

TEST_CASE("custom serializer for pods" * doctest::test_suite("udt"))
{
 using custom_json =
 nlohmann::basic_json<std::map, std::vector, std::string, bool,
 std::int64_t, std::uint64_t, double, std::allocator, pod_serializer>;

 auto p = udt::small_pod{42, '/', 42};
 custom_json const j = p;

 auto p2 = j.get<udt::small_pod>();

 CHECK(p == p2);

 auto np = udt::non_pod{{"non-pod"}};
 custom_json const j2 = np;
 auto np2 = j2.get<udt::non_pod>();
 CHECK(np == np2);
}

template <typename T, typename>
struct another_adl_serializer;

using custom_json = nlohmann::basic_json<std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t, double, std::allocator, another_adl_serializer>;

template <typename T, typename>
struct another_adl_serializer
{
 static void from_json(const custom_json& j, T& t)
 {
 using nlohmann::from_json;
 from_json(j, t);
 }

 static void to_json(custom_json& j, const T& t)
 {
 using nlohmann::to_json;
 to_json(j, t);
 }
};

TEST_CASE("custom serializer that does adl by default" * doctest::test_suite("udt"))
{
 auto me = udt::person{{23}, {"theo"}, udt::country::france};

 json const j = me;
 custom_json const cj = me;

 CHECK(j.dump() == cj.dump());

 CHECK(me == j.get<udt::person>());
 CHECK(me == cj.get<udt::person>());
}

TEST_CASE("different basic_json types conversions")
{
 SECTION("null")
 {
 json const j;
 custom_json cj = j;
 CHECK(cj == nullptr);
 }

 SECTION("boolean")
 {
 json const j = true;
 custom_json cj = j;
 CHECK(cj == true);
 }

 SECTION("discarded")
 {
 json const j(json::value_t::discarded);
 custom_json cj;
 CHECK_NOTHROW(cj = j);
 CHECK(cj.type() == custom_json::value_t::discarded);
 }

 SECTION("array")
 {
 json const j = {1, 2, 3};
 custom_json const cj = j;
 CHECK((cj == std::vector<int> {1, 2, 3}));
 }

 SECTION("integer")
 {
 json const j = 42;
 custom_json cj = j;
 CHECK(cj == 42);
 }

 SECTION("float")
 {
 json const j = 42.0;
 custom_json cj = j;
 CHECK(cj == 42.0);
 }

 SECTION("unsigned")
 {
 json const j = 42u;
 custom_json cj = j;
 CHECK(cj == 42u);
 }

 SECTION("string")
 {
 json const j = "forty-two";
 custom_json cj = j;
 CHECK(cj == "forty-two");
 }

 SECTION("binary")
 {
 json j = json::binary({1, 2, 3}, 42);
 custom_json cj = j;
 CHECK(cj.get_binary().subtype() == 42);
 std::vector<std::uint8_t> cv = cj.get_binary();
 std::vector<std::uint8_t> v = j.get_binary();
 CHECK(cv == v);
 }

 SECTION("object")
 {
 json const j = {{"forty", "two"}};
 custom_json cj = j;
 auto m = j.get<std::map<std::string, std::string>>();
 CHECK(cj == m);
 }

 SECTION("get<custom_json>")
 {
 json const j = 42;
 custom_json cj = j.get<custom_json>();
 CHECK(cj == 42);
 }
}

namespace
{
struct incomplete;

// std::is_constructible is broken on macOS' libc++
// use the cppreference implementation

template <typename T, typename = void>
struct is_constructible_patched : std::false_type {};

template <typename T>
struct is_constructible_patched<T, decltype(void(json(std::declval<T>())))> : std::true_type {};
} // namespace

TEST_CASE("an incomplete type does not trigger a compiler error in non-evaluated context" * doctest::test_suite("udt"))
{
 static_assert(!is_constructible_patched<json, incomplete>::value, "");
}

namespace
{
class Evil
{
 public:
 Evil() = default;
 template <typename T>
 Evil(T t) : m_i(sizeof(t))
 {
 static_cast<void>(t); // fix MSVC's C4100 warning
 }

 int m_i = 0;
};

void from_json(const json& /*unused*/, Evil& /*unused*/) {}
} // namespace

TEST_CASE("Issue #924")
{
 // Prevent get<std::vector<Evil>>() to throw
 auto j = json::array();

 CHECK_NOTHROW(j.get<Evil>());
 CHECK_NOTHROW(j.get<std::vector<Evil>>());

 // silence Wunused-template warnings
 Evil e(1);
 CHECK(e.m_i >= 0);
}

TEST_CASE("Issue #1237")
{
 struct non_convertible_type {};
 static_assert(!std::is_convertible<json, non_convertible_type>::value, "");
}

namespace
{
class no_iterator_type
{
 public:
 no_iterator_type(std::initializer_list<int> l)
 : _v(l)
 {}

 std::vector<int>::const_iterator begin() const
 {
 return _v.begin();
 }

 std::vector<int>::const_iterator end() const
 {
 return _v.end();
 }

 private:
 std::vector<int> _v;
};
} // namespace

TEST_CASE("compatible array type, without iterator type alias")
{
 no_iterator_type const vec{1, 2, 3};
 json const j = vec;
}

DOCTEST_GCC_SUPPRESS_WARNING_POP