[Development] qMoveToConst helper for rvalue references to movable Qt containers?

[Sérgio Martins]

On Sat, Oct 20, 2018 at 1:44 PM Elvis Stansvik <elvstone at gmail.com> wrote:
>
> Hi all (first post),

Welcome :)

> In Qt 5.7+ there's qAsConst, an std::as_const implementation for those
> who are not on C++17 yet, which is convenient for iterating over Qt
> containers using range-based for loops without causing a detach.
>
> For good reasons there's no version of qAsConst that takes an rvalue
> reference, so you can't do e.g. for (auto foo :
> qAsConst(returnsQtContainer())  { ... }. Instead you must do const
> auto stuff = returnsQtContainer(); for (auto foo : stuff) { ... }.

Should we instead just encourage people to make returnsQtContainer()
return a const container ?
Not sure what's the reason we don't do it in Qt. It's frowned upon for
regular value types, but our containers are special.

Regards,
Sergio