llvm-project

ad1ca5f4 - [clang] Concepts: support pack expansions for type constraints (#132626)

[clang] Concepts: support pack expansions for type constraints (#132626) This reverts an earlier attempt (adb0d8ddceb143749c519d14b8b31b481071da77 and 50e5411e4247421fd606f0a206682fcdf0303ae3) to support these expansions, which was limited to type arguments and which subverted the purpose of SubstTemplateTypeParmType. This propagates the ArgumentPackSubstitutionIndex along with the AssociatedConstraint, so that the pack expansion works, without needing any new transforms or otherwise any changes to the template instantiation process. This keeps the tests from the reverted commits, and adds a few more showing the new solution also works for NTTPs. Fixes https://github.com/llvm/llvm-project/issues/131798