tree 2891b9561e45f421cc0b5fc49b605695dbcbd0b1
parent 342eb6837e7ac93acd0c1b46b973e2486577cfff
author Arthur O'Dwyer <arthur.j.odwyer@gmail.com> 1612392853 -0500
committer Copybara-Service <copybara-worker@google.com> 1612558270 -0800

[libc++] Further improve the contiguous-iterator story, and fix some bugs.

- Quality-of-implementation: Avoid calling __unwrap_iter in constexpr contexts.
    The user might conceivably write a contiguous iterator where normal iterator
    arithmetic is constexpr-friendly but `std::to_address(it)` isn't.

- Bugfix: When you pass contiguous iterators to `std::copy`, you should get
    back your contiguous iterator type, not a raw pointer. That means that
    libc++ can't `__unwrap_iter` unless it also does `__rewrap_iter`.
    Fortunately, this is implementable.

- Improve test coverage of the new `contiguous_iterator` test iterator.
    This catches the bug described above.

- Tests: Stop testing that we can `std::copy` //into// an `input_iterator`.
    Our test iterators may currently support that, but it seems nonsensical to me.

Differential Revision: https://reviews.llvm.org/D95983

GitOrigin-RevId: 85167fb7c2920ca8874b197ef397e8e6b9d87c73