List.end().value should throw an out_of_range error

[samchon]

Summary

• TSTL version: 2.3.0
• Expected behavior: accessing to List.end().value throws an out_of_range error
• Actual behavior: accessing to List.end().value is possible (initial value: undefined)

Code occuring the bug

import { List } from "tstl";

function main(): void
{
    let l: List<number> = new List();

    l.end().value; // No error, but returns undefined
    l.end().value = 3; // No error, but possible
}
main();

Detailed Story

When accessing to Vector.end().value, it throws an out_of_range error. However, the List.end().value does not throw the out_of_range exception. It returns the undefined value. Even configuring is to the List.end().value is also possible.

This story is also applicable to the ForwardList and even associate containers like HashSet and TreeMultiMap. The associative containers, they manage elements using the List container. Therefore, if an user try to access mapped-value to the end position like Associative.end().second, the error message would be JS native error; Cannot set property 'second' of undefined. The native error message can't represent the exact reason and situation.

To keep the consistency and immediacy, I believe that the List should throw an out_of_range error when accessing to the List.end().value, even though it's not the regular spec of C++/STL standard.

import { TreeMap } from "tstl";

function main(): void
{
    let m: TreeMap<number, string> = new TreeMap();
    m.end().second = "something"; 
        // Error.message -> Cannot set property 'second' of undefined
        // throwing out_of_range error would be much eloquent
}