Include the unexpanded packs in the initializer expression when checking a
pack expanded constructor initializer list. Fixes PR16303!

llvm-svn: 183878
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 030b9c7..c947bcc 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -3165,8 +3165,9 @@
     if (Init->isPackExpansion()) {
       // This is a pack expansion. We should expand it now.
       TypeLoc BaseTL = Init->getTypeSourceInfo()->getTypeLoc();
-      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+      SmallVector<UnexpandedParameterPack, 4> Unexpanded;
       collectUnexpandedParameterPacks(BaseTL, Unexpanded);
+      collectUnexpandedParameterPacks(Init->getInit(), Unexpanded);
       bool ShouldExpand = false;
       bool RetainExpansion = false;
       Optional<unsigned> NumExpansions;