static assert(version(x)) ?

[Dennis]

On Tuesday, 26 November 2019 at 10:24:00 UTC, Robert M. Münch 
wrote:
> How can I write something like this to check if any of a set of 
> specific versions is used?

```
version(a) {}
else version(b) {}
else version(c) {}
else {
    static assert(0, "only versions a, b and c are supported");
}
```

```
version(a) version = supported;
version(b) version = supported;
version(c) version = supported;
version(supported) {
     // good to go
} else {
     static assert(0, "not a supported version");
}
```

> static assert(!(version(a) | version(b) | version(c)):

That seems to be the opposite of what you describe.
If you want that, then:
```
version(a) static assert(0, "version a not supported");
version(b) static assert(0, "version b not supported");
version(c) static assert(0, "version c not supported");
```