[Bug middle-end/54202] Overeager warning about freeing non-heap objects

[dangelog at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54202

Giuseppe D'Angelo <dangelog at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |dangelog at gmail dot com

--- Comment #8 from Giuseppe D'Angelo <dangelog at gmail dot com> ---
The original testcase by Thiago still fails with GCC 11.

Unfortunately, GCC 11 decided to turn -Wfree-nonheap-object on by default (!),
resulting in false positives for Qt users (containers in Qt use this pattern).
For instance 

https://code.qt.io/cgit/qt/qtbase.git/tree/src/corelib/tools/qlinkedlist.h?h=5.15

struct QT_DEPRECATED_VERSION_5_15 QLinkedListData
{
    QLinkedListData *n, *p;
    QtPrivate::RefCount ref; // set to -1 for shared_null
    int size;
    uint sharable : 1;

    Q_CORE_EXPORT static const QLinkedListData shared_null;
};

template <typename T>
inline QLinkedList<T>::~QLinkedList()
{
    if (!d->ref.deref())
        freeData(d); // never called on shared_null because of the check
}


template <typename T>
void QLinkedList<T>::freeData(QLinkedListData *x)
{
    // ...
    delete x; // -Wfree-nonheap-object here
}