how convert the range to slice ?

["Nordlöw" via Digitalmars-d-learn]

On Monday, 2 February 2015 at 16:56:02 UTC, bearophile wrote:
> Nordlöw:
>
>> Is started digging a bit...
>>
>> The magic happens at line 103 in cast.c.
>>
>> How do I most conveniently figure out which members 
>> (functions) a type (e->type) has?
>>
>> I figured I could check for typical InputRange members and 
>> issue a hint about using .array if e->type has them.
>
> It's probably better to ask such questions on GitHub (and to 
> open an enhancement request in Bugzilla).
>
> Bye,
> bearophile

I cracked it. First proof of concept here

https://github.com/nordlow/dmd/commit/40ce0ecf34f90c4d3053c47e9286d7574f596e15