array append result type

[monarch_dodra via Digitalmars-d-learn]

On Monday, 6 October 2014 at 11:28:16 UTC, John Colvin wrote:
> string a;
> char[] b;
> pragma(msg, typeof(a ~ b)); // char[]
>
> why not string?
>
> What are the rules that determine this?

*Ideally*, I'd have said "it returns char[], so that you can 
chose via purity".

However, it's not pure, so that argument doesn't hold.

That said, casting to immutable is safe provided you never 
actually mutate. The reverse isn't true.

To answer the question directly though, I don't know what the 
rules are. I'd guess they are mostly "whatever druntime 
implemented" though...