Conditionally Borrowed Ranges

[Adam Bucior (AdamBucior)]

Fixes #1682.

[Michael Schellenberger Costa (miscco)]

Looks good to me!

Did you verify that we actually test against a borrowed range?

[Adam Bucior (AdamBucior)]

Did you verify that we actually test against a borrowed range?

I don't have a deep understanding of the ranges test stuff, but implementing this forced me to fix the common view test, so it seems we do.

[Michael Schellenberger Costa (miscco)]

Did you verify that we actually test against a borrowed range?

I don't have a deep understanding of the ranges test stuff, but implementing this forced me to fix the common view test, so it seems we do.

As long as we use a span, we should be fine

[Michael Schellenberger Costa (miscco)]

Did you verify that we actually test against a borrowed range?

I don't have a deep understanding of the ranges test stuff, but implementing this forced me to fix the common view test, so it seems we do.

As long as we use a span, we should be fine

We need to add borrowed range support via a span to take_view and drop_view the other already test it

Something along those lines should do it

    // Validate a non-view borrowed range
    {
        constexpr span s{some_ints};
        STATIC_ASSERT(test_one(s, expected_output));
        test_one(s, expected_output);
    }

    { // Validate a view borrowed range

        constexpr auto v =
            views::iota(0ull, ranges::size(some_ints)) | std::views::transform([](auto i) { return some_ints[i]; });
        STATIC_ASSERT(test_one(v));
        test_one(v);
    }

[Stephan T. Lavavej (StephanTLavavej)]

Thanks for implementing this LWG issue resolution! 🚀 😻 🎉