More operators inside `is(...)` expressions

[Alexandru Ermicioi]

On Tuesday, 25 August 2020 at 12:55:34 UTC, Steven Schveighoffer 
wrote:
> On 8/25/20 3:12 AM, Alexandru Ermicioi wrote:
>> On Monday, 24 August 2020 at 12:28:27 UTC, Stefan Koch wrote:
>>> 1) Complicating the rules for is expressions further
>> 
>> It will complicate a lot more since, you can do type matching 
>> chains in is expression:
>> 
>> ------
>> is(T : Z[], Z != X, X : SomeType)
>> ------
>> 
>
> That doesn't look valid according to the grammar. Or if it 
> passes, it may not do what you think it does. You sure this 
> works?
>
> -Steve

Ah, sorry for bad english. It should be "could do type matching" 
not "can". If support for negation is added inside is expression, 
then it should also be supported in such chains as above, not 
just the simplest case as suggested by other people in this 
discussion.