Pure delegate not quite pure?

[Steven Schveighoffer via Digitalmars-d-learn]

On 6/30/15 5:23 PM, Tofu Ninja wrote:
> On Sunday, 28 June 2015 at 10:19:05 UTC, anonymous wrote:
>> [...]
>
> Is there any way to annotate the context as const?

const x = 4 ;)

But even if you could annotate just the *reference* as const, it doesn't 
stop foo from changing it as you did in the example.

-Steve