I hope you and that proposal will consider allowing the creation of default
member functions of classes that have const members and references by
taking advantage of "transparently replaceable".

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c12-dont-make-data-members-const-or-references-in-a-copyable-or-movable-type
https://stackoverflow.com/questions/4136156/const-member-and-assignment-operator-how-to-avoid-the-undefined-behavior
https://timsong-cpp.github.io/cppwp/n4861/basic.life#8




On Sun, Jun 22, 2025 at 6:31 AM Matthew Taylor via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> I believe this exact topic came under discussion in EWG last week as part
> of the discussion on potential extensions to P2034 Partially Mutable Lambda
> Captures (
> https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2024/p2034r4.pdf).
> Stronger consensus was found to see a version of the paper with extensions
> such as const-ref-capture.
>
> Perhaps it would be a good idea to reach out to the authors of P2034 to
> see if they would collaborate on designing such extensions.
>
> FWIW to answer your question about other qualifiers - I can see the
> symmetry argument for volatile, but I'd want to see a really compelling
> use-case to approve adding more volatile to the language.
>
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