Generate a pointer to a method of a struct

[kdevel]

On Saturday, 15 October 2022 at 00:31:47 UTC, Iain Buclaw wrote:
>> ```
>> auto funcptr (alias method) ()
>> {
>>    return &method;
>> }
>>       :
>>       fun = funcptr!bar;
>>       :
>> ```
>>
>> Which works but neither dmd nor gdc were able to optimize the 
>> additional function call away.
>
> pragma(inline, true)
> auto funcptr (alias method) ()

Thanks. Just found that

```
template funcptr (alias method) {
    enum funcptr = &method;
}
```

works on both dmd and gdc. This gives rise to questions:

Is this code expected to compile and pass its unittest?

```
struct S {
    void bar () { }
}

enum ei = &S.bar;
immutable i = &S.bar;  // line 6
const c = &S.bar;      // line 7

unittest {
    import std.stdio;
    writeln (ei);
    writeln (i);
    writeln (c);
}
```

gdc passes while dmd says:

```
$ dmd -unittest -main -run ini
ini.d(6): Error: non-constant expression `& bar`
ini.d(7): Error: non-constant expression `& bar`
```

Is this consistent?