Fixed a -Wunused-variable warning when assertions are disabled

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@361353 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AST/ExprConstant.cpp

@@ -5033,6 +5033,7 @@ static bool HandleUnionActiveMemberChange(EvalInfo &Info, const Expr *LHSExpr,
         break;
       for (const CXXBaseSpecifier *Elt : ICE->path()) {
         --PathLength;
+        (void)Elt;
         assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(),
                                   LHS.Designator.Entries[PathLength]
                                       .getAsBaseOrMember().getPointer()));