[libcxx-commits] [libcxx] [libc++][test] Test `flat_meow` with proper underlying iterators (PR #131290)

[A. Jiang via libcxx-commits]

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@@ -267,6 +267,135 @@ template <class It>
 random_access_iterator(It) -> random_access_iterator<It>;
 #endif
 
+// Since C++20, a container iterator type that is random access is also required to support three-way comparison.
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frederick-vs-ja wrote:

The (possibly only) use case is making `MinSequenceContainer<T>` a proper sequence container since C++20. An alternative approach IMO would be adding `operator<=>` to `random_access_iterator`, but I don't know whether this is desired.

https://github.com/llvm/llvm-project/pull/131290