Function without 'this' cannot be 'shared'

[Ruby The Roobster]

Take the following code:

```d
void main() //Can be empty, problem occurs regardless
{
}

int test(int a) //Test function.
{
    return 3 * a;
}
//Now overload it for shared...
int test(shared int a) shared
{
     return cast(shared(int))test(cast(int)a); //Note:  The 
problem still happens regardless whether you have this line or 
not.
}
```

Compiling on the latest version, the compiler output you get 
should be(assuming the file is named test.d):

```
Error:  function 'test.test' without 'this' cannot be 'shared'
```