[clang] [BoundsSafety][Sema] Allow counted_by and counted_by_or_null on pointers where the pointee type is incomplete but potentially completable (PR #106321)

[via cfe-commits]

================
@@ -3907,6 +3923,31 @@ CountAttributedType::CountAttributedType(
     DeclSlot[i] = CoupledDecls[i];
 }
 
+StringRef CountAttributedType::getAttributeName(bool WithMacroPrefix) const {
+// TODO: This method isn't really ideal because it doesn't return the spelling
+// of the attribute that was used in the user's code. This method is used for
+// diagnostics so the fact it doesn't use the spelling of the attribute in
+// the user's code could be confusing (#113585).
+#define ENUMERATE_ATTRS(PREFIX)                                                \
----------------
Sirraide wrote:

> Hmm actually I think I would need support for `constexpr` `std::string` to implement this

(fyi, even `constexpr std::string` wouldn’t be enough; an implementation of this that uses `std::string` would require non-transient `constexpr` allocation, which is something people are working on, but it’s not in the standard yet and no compiler supports anything like it afaik)

https://github.com/llvm/llvm-project/pull/106321