front stability

[Jack Stouffer via Digitalmars-d]

On Thursday, 30 June 2016 at 14:59:11 UTC, jmh530 wrote:
> It looks like this is just documentation changes. This really 
> doesn't prevent anyone from making a Range that violates front 
> stability.

No, but what it will do is to make it clear that these are either 
bugs or intended behavior, as this is still a point of 
disagreement.

> For instance, suppose isInputRange is changed so that
>
> auto h = r.front; // can get the front of the range
>
> becomes
>
> auto h = r.front; // can get the front of the range
> auto j = r.front;
> assert(h == j);  //ensure front stability

This cannot be done at compile time.