"for" statement issue

[Steven Schveighoffer via Digitalmars-d]

On 10/21/16 10:28 AM, Kagamin wrote:
> On Friday, 21 October 2016 at 14:16:26 UTC, Steven Schveighoffer wrote:
>> How about in general forbidding lambda statements that aren't called
>> or used anywhere?
>
> How?
>
> int main()
> {
>     int a;
>     auto b = ()=>{a++;};
>     b();
>     assert(a==1);
>     return 0;
> }

This lambda is both used in an assignment, and called.

If I do this:

10;

It's flagged as not having any effect. Similarly if I do:

() => 5;

Then it's not used/called. What is the point?

-Steve