[clang] [Sema]Substitue parameter packs when deduced from function parameter (PR #79371)

[Gábor Spaits via cfe-commits]

================
@@ -431,6 +442,17 @@ namespace deduction_after_explicit_pack {
     i<int, int>(0, 1, 2, 3, 4, 5); // expected-error {{no match}}
   }
 
+  template <typename... T>
+  void bar(args_tag<T...>, type_identity_t<T>..., int mid, type_identity_t<T>...) {}
----------------
spaits wrote:

It could work. It would cost only condition being removed. I deliberately put in the condition that disables this. Should I enable it?

I think enabling it would be standard compliant, but I played it safe and stuck to the example seen in the issue.  

https://github.com/llvm/llvm-project/pull/79371