[libcxx-commits] [libcxx] [libc++] P2770R0: "Stashing stashing iterators for proper flattening" (PR #66033)

[Jakub Mazurkiewicz via libcxx-commits]

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@@ -84,11 +82,16 @@ namespace ranges {
     template <class>
     friend struct std::__segmented_iterator_traits;
 
-    static constexpr bool _UseCache = !is_reference_v<_InnerRange>;
-    using _Cache = _If<_UseCache, __non_propagating_cache<remove_cvref_t<_InnerRange>>, __empty_cache>;
-    _LIBCPP_NO_UNIQUE_ADDRESS _Cache __cache_;
     _LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
 
+    static constexpr bool _UseOuterCache = !forward_range<_View>;
+    using _OuterCache = _If<_UseOuterCache, __non_propagating_cache<iterator_t<_View>>, __empty_cache>;
+    _LIBCPP_NO_UNIQUE_ADDRESS _OuterCache __outer_;
+
+    static constexpr bool _UseInnerCache = !is_reference_v<_InnerRange>;
+    using _InnerCache = _If<_UseInnerCache, __non_propagating_cache<remove_cvref_t<_InnerRange>>, __empty_cache>;
+    _LIBCPP_NO_UNIQUE_ADDRESS _InnerCache __inner_;
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JMazurkiewicz wrote:

I think I'm going to leave it as it is (for now). Other range adaptors (like `drop_while_view`, `filter_view`, `chunk_by_view`) use similar style.

I can address your comment in follow-up PR to clean up style in other adaptors too.

https://github.com/llvm/llvm-project/pull/66033