lib/Sema/SemaTemplateDeduction.cpp

406   if (auto *Expansion = dyn_cast<PackExpansionType>(ParamType))
407     ParamType = Expansion->getPattern();
741         if (auto *Expansion = dyn_cast<PackExpansionType>(NTTP->getType()))
742           ExtraDeductions.push_back(Expansion->getPattern());
1030     const PackExpansionType *Expansion
1032     if (!Expansion) {
1065     QualType Pattern = Expansion->getPattern();
1099       Optional<unsigned> NumExpansions = Expansion->getNumExpansions();
5505   if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E))
5506     E = Expansion->getPattern();