One more method for STL compatibility. This one is particularly subtle as it's required by the `reservable-container` concept: https://eel.is/c++draft/ranges#range.utility.conv.general-3 Without this concept, ranges::to won't reserve() before copying the elements (out of a sized range which isn't a common_range). Implementation notes: there were already a couple of constants denoting the maximum QByteArray and QString size. Centralize that implementation in QTypedArrayData, so that QList can use it too. The maximum allocation size (private constant) needs a even more central place so that even QVLA can use it. Lacking anything better, I've put it in qcontainerfwd.h. Since our containers aren't allocator-aware, I can make max_size() a static member, and replace the existing constants throughout the rest of qtbase. (I can't kill them yet as they're used by other submodules.) [ChangeLog][QtCore][QList] Added max_size(). [ChangeLog][QtCore][QString] Added max_size(). [ChangeLog][QtCore][QByteArray] Added max_size(). [ChangeLog][QtCore][QVarLengthArray] Added max_size(). Change-Id: I176142e31b998f4f787c96333894b8f6653eb70d Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org> Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>