Class-Inheritancing Error

[David T. Oxygen via Digitalmars-d-learn]

I wrote a piece of code like this:

```d
class Person{
        string name;
        this(string name){this.name=name;}
}
class Someone:Person{
        alias super this;
}
void main(){
        Someone x=new Someone("Bob");
}
```
And then,I got a Error-Message:
```
ab.d(6): Error: variable name expected after type `super`, not 
`this`
    alias super this;
                ^
ab.d(6):        `this` is a keyword, perhaps append `_` to make 
it an identifier

```
Who knows why I can't use `alias this` there? Please tell 
me,thanks very much. I'm waiting for you.