Is this a bug in std.typecons.Tuple.slice?

[tsbockman via Digitalmars-d-learn]

On Saturday, 6 February 2016 at 06:34:05 UTC, Marco Leise wrote:
> I don't want to sound dismissive, but when that thought came
> to my mind I considered it unacceptable that the type of
> Tuple!(int, bool, string).slice(1, 3) would be something
> different than Tuple!(bool, string). In your case
> Tuple!(TuplePad!4LU, bool, string). That's just a matter of
> least surprise when comparing the types.
>
> I'll let others decide, since I never used tuple slices.

I'm not sure which approach is ultimately better, but aside from 
the performance implications, your "needed change" could break a 
lot of valid code in the wild - or it might break none; it really 
just depends on whether anyone actually *uses* the `ref`-ness of 
the `Tuple.slice` return type.

(It appears that Phobos, at least, does not. But there is no 
guarantee that the rest of the world is using `Tuple` only in the 
ways that Phobos does.)

Leaving aside bizarre meta-programming stuff (because then 
*anything* is a breaking change), my PR does not break any code, 
except that which was already broken: the type of the slice is 
only different in those cases where it *has* to be, for alignment 
reasons; otherwise it remains the same as it was before.