In a graph library I'm working on I have the following algorithm

bool hasContext(Node sub,    // TODO in
                Node sup) nothrow // TODO in
{
    Node curr = sub;
    while (true)
    {
        Node ctx = curr.context;
        if (!ctx) { break;}
        if (ctx is sup)
            return true;
        else
            curr = ctx;
    }
    return false;
}

When I qualify the parameters `sub`, `sup` and `curr` with const, the assignment

    curr = ctx;

fails.

1. Is there a way to express tail-constness on the parameters without having to qualify this function with @trusted to enable an ugly const-cast to allow the assignment `curr = ctx` to compile?

2. An alternative solution is to make the function recursive. But will that be as efficient?

On Monday, 25 December 2017 at 14:49:11 UTC, Nordlöw wrote:
> 1. Is there a way to express tail-constness on the parameters

https://dlang.org/phobos/std_typecons.html#Rebindable

On Monday, 25 December 2017 at 15:16:55 UTC, ag0aep6g wrote:
> https://dlang.org/phobos/std_typecons.html#Rebindable

Thanks.