[clang] [Sema] Preserve ContainsUnexpandedParameterPack in TransformLambdaExpr (PR #86265)

[via cfe-commits]

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@@ -170,6 +194,17 @@ namespace {
       if (D && D->isParameterPack())
         return true;
 
+      if (D && D->isFunctionOrFunctionTemplate()) {
+        FunctionDecl *FD;
+        if (auto *FTD = dyn_cast<FunctionTemplateDecl>(D))
+          FD = FTD->getTemplatedDecl();
+        else
+          FD = cast<FunctionDecl>(D);
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cor3ntin wrote:

Do we not have functions to do that somewhere? I feel like i see that sort of pattern all over

https://github.com/llvm/llvm-project/pull/86265