how convert the range to slice ?

["Nordlöw" via Digitalmars-d-learn]

On Wednesday, 28 January 2015 at 14:54:27 UTC, data man wrote:
> auto arr1 = [1,2,3].map!"a*2".array;
> auto arr2 = [1,2,3].filter!"a<3".array;

Is there any chance we could add logic to dmd+phobos that hints 
user about this?