Getting the address of a member function at compile time inside a member function

[Steven Schveighoffer]

On Sunday, 13 July 2025 at 02:53:24 UTC, Walter Bright wrote:
> On 7/6/2025 8:28 PM, Steven Schveighoffer wrote:
>> It seems the act of being in a member function engages the 
>> compiler to try and add a context pointer. And there's no way 
>> to turn this off, except to not be in a member function.
>
> But non-static member functions must have a context pointer! 
> It's the whole point.

In general, this function pointer is still a valid function 
pointer, and there is value to accessing the pointer. e.g. 
`assert(dg.funcptr == &S.foo);`

Note, you can use function pointers to build delegates:

```d
import std.stdio;
import std.random;

struct S
{
    void foo() { writeln("foo"); }
    void bar() { writeln("bar"); }
}

void main()
{
    void function()[] fns = [&S.foo, &S.bar];
    void delegate() dg;
    S s;
    dg.ptr = &s;
    dg.funcptr = fns[uniform(0, 2)];
    dg();
}
```

I would be excited if D could improve on this. Perhaps by 
allowing a type like `void function(ref S this)`, which actually 
could be called with an `S`. It could also make delegate types 
more useful and safer.

-Steve