qt QFlags:有符号的值超出枚举常量的范围

template <typename Enum>
class QFlags
{
public:
    QFlags(Enum value);
    QFlags(const QFlags &other);
    QFlags &operator=(const QFlags &other);
    operator int() const;
    operator Enum() const;
    QFlags operator|(Enum flag) const;
    QFlags operator|(const QFlags &other) const;
    QFlags &operator|=(Enum flag);
    QFlags &operator|=(const QFlags &other);
    QFlags operator&(Enum flag) const;
    QFlags operator&(const QFlags &other) const;
    QFlags &operator&=(Enum flag);
    QFlags &operator&=(const QFlags &other);
    QFlags operator^(Enum flag) const;
    QFlags operator^(const QFlags &other) const;
    QFlags &operator^=(Enum flag);
    QFlags &operator^=(const QFlags &other);
    QFlags operator~() const;
    bool operator!() const;
    bool testFlag(Enum flag) const;
    QFlags &setFlag(Enum flag, bool on = true);
    QFlags &setFlags(Enum flags);
    QFlags &clearFlag(Enum flag);
    QFlags &clearFlags();
    bool operator==(const QFlags &other) const;
    bool operator!=(const QFlags &other) const;
};