Parse an object but get an array using GCC

[SlavaMelanko]

I will start with an example:

class Doc
{
public:
    explicit Doc(const std::string &data)
        : m_doc{nlohmann::json::parse(data)}
    {}

    auto dump() const { return m_doc.dump(); }

private:
    nlohmann::json m_doc;
};

int main()
{
    const std::string data{R"({"value": 1})"};

    auto v = nlohmann::json::parse(data);
    std::cout << v.dump() << std::endl; // {"value":1}

    Doc d{data};
    std::cout << d.dump() << std::endl; // [{"value":1}]

    return 0;
}

Link for compiler explorer

Probably I missed something, but why do I always get an array in the second case using GCC? Clang is ok.

Expected behavior: output must be {"value":1} twice.

Environment:

• I checked on GCC 9 and above
• Json library the latest releases

[nlohmann]

Duplicate of #2583.