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

[Mark de Wever 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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mordante wrote:

I wonder, would it make sense to guard this with `#if TEST_STD_VER >= 20`? Is there a use-case for this iterator given that we already have a `random_access_iterator`?

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