Voldemort declarations inside structs with ctor initialization

[via Digitalmars-d]

On Tuesday, 27 May 2014 at 15:06:53 UTC, bearophile wrote:
>> BTW, why doesn't this example work with lambdas (a => a != 2) 
>> instead of a string mixin ("a != 2")?
>
> I think lambda instantiations defines a different type. So it's 
> incompatible.

Incompatible with what? I meant changing it in both the 
declaration and the initialization.

>> BTW 2, is `this(int = 0)' the best workaround (still?)
>
> I think it's not a good workaround.

What should I use then?