[clang] [clang] Do not substitute parameter pack while retaining the pack expansion (PR #108197)

[Younan Zhang via cfe-commits]

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@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s
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zyn0217 wrote:

Can you move the test to a pre-existing file instead of adding a new one? e.g. somewhere like clang/test/SemaTemplate/pack-deduction.cpp, since this patch is affecting something that has been around for many years.

https://github.com/llvm/llvm-project/pull/108197