If Statement with Declaration

[Johan Engelen via Digitalmars-d]

On Friday, 21 July 2017 at 21:32:48 UTC, Andrei Alexandrescu 
wrote:
> 
> It's bizarre even lexically: "If the following ... oh wait let 
> me insert some stuff ... as I was saying, if the following 
> condition happens..."

(excuse me for muddying the waters)
We do have a construct like that already:
```
static if (is(E V == enum)) { // this inserts "V"
    V v;
}
```

-Johan