(Context: https://learnmoderncpp.com/2022/12/07/applications-of-c23s-deducing-this/ https://learnmoderncpp.com/2022/12/07/applications-of-c23s-d...) While the

(Context: https://learnmoderncpp.com/2022/12/07/applications-of-c23s-deducing-this/ https://learnmoderncpp.com/2022/12/07/applications-of-c23s-d...) While the article describes why you'd want this abomination, honestly, I'd rather opt for the copy-pasted code T& at(size_t x, size_t y) { return data.at(y * X + x); } const T& at(size_t x, size_t y) const { return data.at(y * X + x); } as something that's actually human-legible while also providing const-correctness. If the implementation is actually complicated enough, then sure, use the const_cast variation, but hide it away in a .cc file. This feels like a contrived example to show off new language features. That said, I'd also rather use std::mdspan [0] if I had C++23 available, and not implement my own Matrix struct by hand. [0] https://en.cppreference.com/w/cpp/container/mdspan https://en.cppreference.com/w/cpp/container/mdspan