[Development] Proposal: QVariant/std::any QModelIndex::internalData() for Qt 7

[Thiago Macieira]

On Thursday, 2 July 2026 03:52:32 Pacific Daylight Time Volker Hilsheimer via 
Development wrote:
> Expanding QModelIndex to be more than a short-lived reference to an item in
> the model would perhaps make some specific use cases easier - but at very
> high cost (like heap-allocated QVariants).

Do note that QVariant avoids heap for typical payloads, including void* and 
quintptr. Accessing those using .value<T>() is also inline as of 6.12.

However, using it will make QModelIndex not trivially copyable, movable 
(though moving is inline), or destructible. For large models, this could be a 
problem.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Principal Engineer - Intel DCG - Platform & Sys. Eng.
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