Writing an inc function is a fascinating voyage.A function on module level did not worked because it had no this context.
This works:
```
void main(){
ref int inc2(ref int x) return pure nothrow @nogc @safe{
++x;
return x;
}
int x=0;
inc2(inc2(x));
writeln(x);
```
The thing is i don't find the function pure.
