public TypeInfo typeCheck(TypeEnv tenv) throws TypeException {
TypeInfo[] params = ((ParamListEx2) parameters()).types();
TypeInfo retType = TypeInfo.get(type());
funcType = TypeInfo.function(retType, params);
TypeInfo oldType = tenv.put(0, index, funcType);
if (oldType != null) throw new TypeException("function redefinition: " + name(), this);
bodyEnv = new TypeEnv(size, tenv);
for (int i = 0; i < params.length; i++) bodyEnv.put(0, i, params[i]);
TypeInfo bodyType = ((ASTreeTypeEx) revise(body())).typeCheck(bodyEnv);
bodyType.assertSubtypeOf(retType, tenv, this);
return funcType;
}
