[libcxx-commits] [PATCH] D101079: [libcxx][ranges] Add ranges::size CPO.

[Zoe Carver via Phabricator via libcxx-commits]

zoecarver added inline comments.


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Comment at: libcxx/include/__ranges/size.h:77
+  requires(_Tp&& __t) {
+    // TODO: how do we convert to unsigned?
+    { ranges::begin(__t) } -> forward_iterator;
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cjdb wrote:
> See http://eel.is/c++draft/ranges.syn#1.
> 
> The result needs to be the `iter_difference_t<_Tp>`, and since I've asserted that we only care about (extended) integral types, we're clear to use `make_unsigned_t<iter_difference_t<_Tp>>`.
Okay good to know. `sized_sentinel_for` requires the result to be `iter_difference_t` so I don't think we need to check that here. I'll add a static cast below, though. 


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D101079/new/

https://reviews.llvm.org/D101079