llvm-project

e0eb7c25 - [Clang] Ensure initialized NTTP expressions when building CTAD for type aliases (#161035)

[Clang] Ensure initialized NTTP expressions when building CTAD for type aliases (#161035) We missed calling CheckTemplateArgument when building CTAD deduction guides. That ensures some InitExprs are correctly initialized, as in the test that crashed due to incorrect NTTP initialization. I don't use CheckTemplateArguments because, in CTAD synthesis, template parameter packs don't always appear at the end of the parameter list, unlike user-written ones mandated by the standard. This makes it difficult for CheckTemplateArguments to determine how many arguments a pack in middle should match, leading to unnecessary complexity. On the other hand, since we substitute non-deduced template parameters with deduced ones, we need to fold the packs midway through substitution, where CheckTemplateArgument is more convenient. As a drive-by this also removes some dead code in SemaInit. Fixes #131408