Custom default exception handler?

[Sean Kelly]

On Wednesday, 12 February 2014 at 03:31:38 UTC, Nick Sabalausky
wrote:
>
> Hmm, my custom toString isn't being executed. Am I doing 
> something wrong here? Same result if I inherit direct from 
> Throwable instead of Exception.
>
> class Fail : Exception
> {
>     private this()
>     {
>         super(null);
>     }
>
>     private static Fail opCall(string msg, string 
> file=__FILE__, int line=__LINE__)
>     {
>         auto f = cast(Fail) cast(void*) Fail.classinfo.init;
>
>         f.msg  = msg;
>         f.file = file;
>         f.line = line;
>
>         return f;
>     }
>
>     override string toString()
>     {
>     writeln("In Fail.toString()");
>         return "someapp: ERROR: "~msg;
>     }
>
> }

It looks like this has changed, and the method that's called now
is:

void toString(scope void delegate(in char[]) sink) const;

I suspect this has broken a lot of custom exception messages,
since everything in core.exception still uses toString() for its
output.