It seems QList::last and QList::first on Qt6 is a false-positive for Wclazy-detaching-member.

We get for this a warning.

QStringList list;
list << "dummy";
list.last().append("hello");

But it won't call any detaching.

    inline T& first() { Q_ASSERT(!isEmpty()); return *begin(); }
    inline const T &first() const noexcept { Q_ASSERT(!isEmpty()); return *begin(); }

    inline T& last() { Q_ASSERT(!isEmpty()); return *(end()-1); }
    inline const T &last() const noexcept { Q_ASSERT(!isEmpty()); return *(end()-1); }