[libcxx-commits] [libcxx] [libcxx] changes `__is_allocator` from a struct to a variable or concept (PR #68629)

[via libcxx-commits]

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@@ -21,13 +21,21 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
+#if _LIBCPP_STD_VER >= 20
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philnik777 wrote:

Because the variable template change is (IMO) a pure improvement, while adding a branch increases the complexity of the implementation. IMO this deserves it's own conversation and some evidence that this actually improves diagnostics. The variable template change is also fully self-contained. Making the concept change a follow-up patch makes it much smaller and more focused.

https://github.com/llvm/llvm-project/pull/68629