formals.add("x", new IntArrayVector(1));
formals.add("y", new IntArrayVector(2));
FunctionCall body = FunctionCall.newCall(Symbol.get("+"), Symbol.get("x"), Symbol.get("y"));
Closure closure = new Closure(topLevelContext.getGlobalEnvironment(), formals.build(), body);
assertReRead(closure);
// PairList.Builder list = new Builder();
// list.add("renjin.f", closure);