Before this patch, we would fail to implicitly convert the result of
predicates to bool, which means we'd potentially perform a copy or move
construction of the boolean-testable, which isn't allowed. The same
holds true for comparing iterators against sentinels, which is allowed
to return a boolean-testable type.
We already had tests aiming to ensure correct handling of these types,
but they failed to provide appropriate coverage in several cases due to
guaranteed RVO. This patch fixes the tests, adds tests for missing
algorithms and views, and fixes the actual problems in the code.
Fixes#69074
This also removes some tests which we have grouped together into robust_from_*.pass.cpp tests.
Specifically, checking that
- `ranges::dangling` is returned is done in `libcxx/test/std/algorithms/ranges_robust_against_dangling.pass.cpp`
- `std::invoke` is used is done in `libcxx/test/std/algorithms/ranges_robust_against_omitting_invoke.pass.cpp`.
- implicit conversion to bool works is done in `libcxx/test/std/algorithms/ranges_robust_against_nonbool_predicates.pass.cpp`
Checking the comparison order is invalid because the `operator==` isn't symmetric.
Checking what the exact type of `operator==` is, is invalid because comparing the same object has to yield the same results if the objects are not modified.
Reviewed By: ldionne, #libc
Spies: EricWF, libcxx-commits
Differential Revision: https://reviews.llvm.org/D150588
When we ship LLVM 16, <ranges> won't be considered experimental anymore.
We might as well do this sooner rather than later.
Differential Revision: https://reviews.llvm.org/D132151
