QMap: suppress warning about strict aliasing violation in end()

In:
    Node *end() { return reinterpret_cast<Node *>(&header); }

GCC 10.2 correctly warns that, if you dereferenced this type-punned
pointer (which is of type QMapNodeBase), you'd be violating strict-
aliasing, as there is no object of type QMapNode<Key, T> there. But no
one is supposed to dereference this pointer, it's only used as a
sentinel. So simply suppress the warning.

 qmap.h: In instantiation of ‘QMapData<Key, T>::Node* QMapData<Key, T>::end() [with Key = QString; T = QString; QMapData<Key, T>::Node = QMapNode<QString, QString>]’:
 qmap.h:921:31:   required from ‘int QMap<K, V>::remove(const Key&) [with Key = QString; T = QString]’
 qmap.h:215:52: error: dereferencing type-punned pointer might break strict-aliasing rules [-Werror=strict-aliasing]

-Wstrict-aliasing (level 3) is part of -Wall. I believe this warning
happens with level 2 ("Aggressive, quick, not too precise"), which makes
GCC less accurate, but it's an easy fix.

Doesn't apply to Qt 6 since there QMap was rewritten on top of std::map.

Fixes: QTBUG-88185
Change-Id: I7b9b97ae9b32412abdc6fffd164480bcb515acf5
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

0 files changed, 0 insertions, 0 deletions