[clang] [Clang] Fix Microsoft ABI inheritance model when member pointer is used in a base specifier (PR #91990)

[Reid Kleckner via cfe-commits]

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@@ -215,6 +215,14 @@ struct NewUnspecified;
 SingleTemplate<void (IncSingle::*)()> tmpl_single;
 UnspecTemplate<void (NewUnspecified::*)()> tmpl_unspec;
 
+// Member pointers used in base specifiers force an unspecified inheritance model
+struct MemPtrInBase : UnspecTemplate<void (MemPtrInBase::*)()> {};
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rnk wrote:

Yes, but it's not clear to me if that happens before or after we've finished parsing the base specifiers.

https://github.com/llvm/llvm-project/pull/91990