Just like for `is`, you can omit the `()` in front of the block/lambda here. EG:

```D
is(typeof({T t = t;}));
or
if (functionAttributes!({'a'.toUpper();}) != FunctionAttribute.pure_)
```

Also, I wouldn't complain about a `!= 0` in an if, but it *is* adding an extra pair of parenthesis.

I'll merge this evening regardless.