PR13811: Add a FunctionParmPackExpr node to handle references to function
parameter packs where the reference is not being expanded but the pack has
been. Previously, Clang would segfault in such cases.

llvm-svn: 163672
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 2cd7f04..8f3f84d 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -6480,6 +6480,7 @@
   case Expr::OpaqueValueExprClass:
   case Expr::PackExpansionExprClass:
   case Expr::SubstNonTypeTemplateParmPackExprClass:
+  case Expr::FunctionParmPackExprClass:
   case Expr::AsTypeExprClass:
   case Expr::ObjCIndirectCopyRestoreExprClass:
   case Expr::MaterializeTemporaryExprClass: