Slicing AliasSeq-s

[Marc Schütz via Digitalmars-d]

On Monday, 21 December 2015 at 09:06:08 UTC, Shriramana Sharma 
wrote:
> http://dlang.org/spec/template.html#TemplateTupleParameter
>
> Apart from the obvious need for changing the references to 
> tuples to alias sequences (for which I'm working on a PR), my 
> question:
>
> Both the above page and http://dlang.org/phobos/std_meta.html 
> refer to "slicing" alias sequences. In D slicing means just 
> creating another reference to the same memory as the sliced 
> object.
>
> Given that AliasSeq-s cannot be written to[*], it's not 
> possible for me to test whether it's actually sliced or a new 
> AliasSeq with the same elements is created. Otherwise I could 
> do something like this:
>
> alias A = [int, 2, symbol];
> alias B = A[1 .. $];
> alias C = A[0 .. $ - 1];
> A[1] = 3; // not possible
> static assert(B[0] == 3 && C[1] == 3);
>
> So out of curiosity I'd like to know how this is implemented in 
> the compiler: as really a slice or a copy? (Posting this to D 
> and not learn since it relates to compiler internals.)

I don't know the answer, but I suspect it's a (shallow) copy. 
Anyway, as you've noticed, there's no observable difference 
either way, so this is an implementation detail which the 
documentation shouldn't mention (if this was the intention behind 
your question).