<memory>: ranges::uninitialized_copy and ranges::uninitialized_move fail to compile with trivial types

[AdamBucior]

Describe the bug
ranges::uninitialized_copy and ranges::uninitialized_move fail to compile with trivial types, common first range and non-common second range.

Code

#include <memory>
#include <ranges>

using namespace std;

int main() {
    int arr[3]{0, 1, 2};
    int arr2[3];

    ranges::uninitialized_copy(begin(arr), end(arr), begin(arr2), unreachable_sentinel);
}

Expected behavior
Should compile fine.

STL version
Microsoft Visual Studio Community 2019 Preview
Version 16.10 Preview 1

[miscco]

What is not tested is broken.

We are currently checking for the memory optimization with this:

if constexpr (is_same_v<_Se, _It> && _Ptr_move_cat<_It, _Out>::_Really_trivial) {

This obviously does not account for whether the output range is common. The easy solution is to add is_same_v<_Out, _Se2>

That said, I wonder whether we should expand the optimization up to sized_sentinel_for @CaseyCarter

[CaseyCarter]

That said, I wonder whether we should expand the optimization up to sized_sentinel_for @CaseyCarter

That seems correct given that these algorithms always traverse the ranges from beginning to end so they don't care if the sentinel is or is not an iterator. Commonality is being used here only because it implies (together with the contiguous_iterator requirement) sized_sentinel_for.