How to know if opSlice is defined for a type (including built-in types)?

[chardetm via Digitalmars-d-learn]

On Wednesday, 20 January 2016 at 15:25:10 UTC, Jonathan M Davis 
wrote:
> On Wednesday, January 20, 2016 13:06:00 chardetm via 
> Digitalmars-d-learn wrote:
>> Anyone who has the same problem: I found 
>> std.range.primitives.hasSlicing 
>> (https://dlang.org/phobos/std_range_primitives.html#hasSlicing) which does exactly what I want!
>
> Note that because strings are treated as ranges of dchar 
> regardless of what their actual character type is, arrays of 
> char and wchar (so-called "narrow" strings) are not consider to 
> have slicing or random access by the traits in std.range. So, 
> hasSlicing!string is false, though for anything other than an 
> array of char or wchar, it will do what you're looking for, 
> whereas for arrays of char or wchar, you really shouldn't be 
> using the slice operator on them without knowing that they're 
> what you're operating on so that you take the Unicode issues 
> into account correctly.
>
> - Jonathan M Davis

Yes and that was the next step of my problem, it turned out that 
it was already taken into account by hasSlicing!

Thank you very much!