"for" statement issue

[Vladimir Panteleev via Digitalmars-d]

On Friday, 21 October 2016 at 12:34:58 UTC, Andrei Alexandrescu 
wrote:
> What would be a good solution to forbid certain constructs in 
> the increment part of a for statement?

For this specific case, a clear solution would be to forbid 
evaluating lambdas as a boolean expression, because they will 
always be true, and thus almost always an error. Same as with 
assignments in if statements. If intended, it can be worked 
around with "!is null".