Breaking ";" rule with lambda functions

[pascal111]

On Monday, 1 August 2022 at 14:34:45 UTC, ag0aep6g wrote:
> On Monday, 1 August 2022 at 14:15:31 UTC, pascal111 wrote:
>> Many of D rules are taken from C, we know that, so a general 
>> basic rule is to put ";" after each statement, so the previous 
>> statement of filter should be "auto r = chain(a, b).filter!(a 
>> => a > 0;);"? Why D leaves ";" in this case?
>
> `a => a > 0` is not a statement. It's an expression.

But it is still a "function", and functions make statements!! 
It's not a normal expression.