[libcxx-commits] [PATCH] D99873: [libcxx] adds `std::ranges::iter_move` and `std::iter_rvalue_reference_t`

[Arthur O'Dwyer via Phabricator via libcxx-commits]

Quuxplusone added inline comments.


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Comment at: libcxx/include/__iterator/iter_move.h:59
+  constexpr decltype(auto) operator()(_Ip&& __i) const
+    noexcept(noexcept(*_VSTD::forward<_Ip>(__i)))
+  {
----------------
cjdb wrote:
> This noexcept specifier doesn't account for a throwing move.
"`move` doesn't move," and this function returns `decltype(auto)`, so I think we're okay here. This function either returns an rvalue reference in the `if`, or URVOs a prvalue in the `else`.


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Comment at: libcxx/test/std/iterators/iterator.requirements/iterator.cust/iterator.cust.move/iter_move.pass.cpp:186
+  static_assert(check_iter_move());
+  assert(check_iter_move());
+
----------------
zoecarver wrote:
> cjdb wrote:
> > zoecarver wrote:
> > > ldionne wrote:
> > > > cjdb wrote:
> > > > > zoecarver wrote:
> > > > > > No need to call assert here. 
> > > > > Don't we want to check the run-time value as well?
> > > > Yes, I think we do. I'm leaving the `assert` in place.
> > > Why do we want to check the runtime value? The end of `check_iter_move` is `return true;` we're not "checking" anything. 
> > Sure, but the contents of `check_iter_move` need to be evaluated at both compile-time and run-time.
> I agree. But why can't you just call `check_iter_move` normally? Why do you need the assert? 
+1 @zoecarver 


Repository:
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  https://reviews.llvm.org/D99873/new/

https://reviews.llvm.org/D99873