(Local) right.getOp(), st);
// check all definitions, all must be invocations of next()
for (Unit unit : defsOfAt) {
if (unit instanceof AssignStmt) {
AssignStmt assign = (AssignStmt) unit;
if (assign.containsInvokeExpr()) {
InvokeExpr invokeExpr = assign.getInvokeExpr();
if (!resolver.isNext(invokeExpr.getMethod()))
return false;
} else
// new, cast ...