void foo() {
    static std::map<std::string, std::string> fooMap =
    {
        { "First", "ABC" },
        { "Second", "DEF" }
    };
}

class Bar {
    public:
        Bar();
    private:
        std::map<std::string, std::string> barMap;
};

Bar::Bar() {
    barMap = { // <-- this is the error line
        { "First", "ABC" },
        { "Second", "DEF" }
    };
}