[libcxx-commits] [libcxx] [libc++] Fix incomplete user-defined ctype specialization in test (PR #74630)

[Louis Dionne via libcxx-commits]

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@@ -73,15 +71,53 @@ struct char_traits<Char> {
   static int_type eof() { return char_traits<char>::eof(); }
 };
 
+// This ctype specialization treats all characters as spaces
 template <>
-class ctype<Char> : public locale::facet {
+class ctype<Char> : public locale::facet, public ctype_base {
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ldionne wrote:

Yeah I noticed that you folks had `locale::facet` deriving from `ctype_base` (or the other way around) when I tested this on Godbolt. I think it makes it impossible for users to implement a specialization of `ctype` in a conforming way, but I understand this is not really something you can fix.

I'd be OK with an `#ifdef` for this case.

https://github.com/llvm/llvm-project/pull/74630