Idea: Immutable blocks within functions

[Peter Alexander]

On Saturday, 7 September 2013 at 22:57:40 UTC, Xinok wrote:
> 	immutable
> 	{
> 		int[] arr = ...;
> 		int[] arr2 = arr.dup;
> 		sort(arr); // arr is still mutable
> 		
> 		int[] arr2 = arr.dup;
> 		reverse(arr2);
> 		arr ~= arr2;
> 	}

How do you stop mutable references escaping in functions called 
from the immutable block?

e.g.

int* p;
void foo(ref int x) { p = &x; }

void main()
{
     immutable
     {
         int x = 1;
         foo(x);
     }
     *p = 0;
}