cast to pure function stop work after upgrade

[vit]

On Monday, 2 August 2021 at 11:28:46 UTC, Tejas wrote:
> On Monday, 14 June 2021 at 13:31:51 UTC, baby_tiger wrote:
>> [...]
>
>
> It seems to not work at runtime either. Maybe they've made this 
> behaviour illegal now? Hopefully someone answers.
>
> ```d
>
> import std.traits;
> import core.stdc.stdarg;
>         enum LogLevel : ubyte {
>                 INFO = 0,
>                 WARN,
>                 ERROR,
>                 FATAL,
>         }
>
>
> extern (C) string VFORMAT(LogLevel level, string file, size_t 
> line, char[] tmp, bool line_break, string tag, string fmt, ...) 
> @nogc nothrow {
>         return null;
> }
>
> extern (C) string function(LogLevel level, string file, size_t 
> line, char[] tmp, bool line_break, string tag, string fmt, ...) 
> @nogc nothrow pure fp;
> void main(){
>     fp = &VFORMAT; //fails
> }
> ```

Try this:
```d
void main(){
     fp = cast(typeof(fp))&VFORMAT; //fails
}
```