# Language rules inheritance

A language ruleset is a combination of its `rules-` and `not-` rules.

`rules-` dictate how to use features available in this version of the language.

`not-` rules restrict features will not be available until the next version of the language.

`rules-` inherit previous versions, whereas `not-` rules inherit future versions.

```
                 ⋮

rules-es2017 ← es2017 → not-es2017

     ↓                      ↑

rules-es2016 ← es2016 → not-es2016

     ↓                      ↑

 rules-es6   ←  es6   →  not-es6

     ↓                      ↑

 rules-es5   ←  es5   →  not-es5

                 ⋮
```

`es2015` is provided an alias of `es6`