LWG2593: Moved-from state of Allocators

[cjdb]

Link: https://wg21.link/lwg2593

[llvmbot]

@llvm/issue-subscribers-c-20

Author: Christopher Di Bella (cjdb)

[frederick-vs-ja]

Possibly nothing to do. I'm not aware of libc++ (or any other standard library implementation) even provided such a weird allocator type which did't meet the strengthened requirement.

But the test_allocator in the test suits needs to be fixed.

llvm-project/libcxx/test/support/test_allocator.h

Lines 121 to 130 in 8b26c02

	TEST_CONSTEXPR_CXX14 test_allocator(test_allocator&& a) TEST_NOEXCEPT : data_(a.data_), id_(a.id_), stats_(a.stats_) {
	if (stats_ != nullptr) {
	++stats_->count;
	++stats_->moved;
	}
	assert(a.data_ != test_alloc_base::destructed_value && a.id_ != test_alloc_base::destructed_value &&
	"moving from destroyed allocator");
	a.data_ = test_alloc_base::moved_value;
	a.id_ = test_alloc_base::moved_value;
	}