is there a reason declarative style if are allowed, but not while ?

[Timon Gehr]

On 26.02.21 21:32, deadalnix wrote:
> D allows for this type of constructs:
> 
> if (auto foo = bar()) { ... }
> 
> I was trying to do something similar with a while loop, but DMD seems 
> very upset about it. Is there a reason to disallow the following?
> 
> while (auto foo = bar()) { ... }
> 
> 


I don't think there's any good reason.

Related: https://issues.dlang.org/show_bug.cgi?id=16140

FWIW, note that this works in C++.