[clang] [Clang][C++26] Implement Pack Indexing (P2662R3). (PR #72644)

[Nikolas Klauser via cfe-commits]

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@@ -978,6 +978,20 @@ bool Parser::ConsumeAndStoreFunctionPrologue(CachedTokens &Toks) {
       } else {
         break;
       }
+      // Pack indexing
+      if (getLangOpts().CPlusPlus26 && Tok.is(tok::ellipsis) &&
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philnik777 wrote:

FWIW it would be really sweet if we could get this in older language modes to implement `std::tuple`. I don't know whether the current version is ABI compatible, but IMO it would definitely be worth looking into it.

https://github.com/llvm/llvm-project/pull/72644