[libcxx-commits] [libcxx] [libc++] optimization on ranges::drop_view::begin (#72883) (PR #72929)

[Will Hawkins via libcxx-commits]

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@@ -104,7 +108,8 @@ namespace ranges {
     constexpr auto begin() const
       requires random_access_range<const _View> && sized_range<const _View>
     {
-      return ranges::next(ranges::begin(__base_), __count_, ranges::end(__base_));
+      range_difference_t<_View> __dist = ranges::distance(__base_);
+      return ranges::begin(__base_) + std::min(__count_, __dist);
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hawkinsw wrote:

Good catch! I missed the nested `iterator_t` inside the definition of the `range_difference_t`. 

And, you're right, that would be evil!

https://github.com/llvm/llvm-project/pull/72929