How can I report what I think a compiler's frontend bug

[Johan Engelen via Digitalmars-d]

On Sunday, 20 March 2016 at 17:57:12 UTC, Vincent R wrote:
> On Sunday, 20 March 2016 at 16:16:18 UTC, Marco Leise wrote:
>> Am Sun, 20 Mar 2016 11:28:19 +0000
>> schrieb Vincent R <lol at dlang.org>:
>>
>>> Hi,
>>> 
>>> I would like to start a new project (a bonjour/zeroconf 
>>> wrapper
>>> and a gui browser using it).
>>> For the gui part I would like to use my existing skills using
>>> wxWidgets wrapper (wxD).
>>> So I have started to report a problem a few months ago:
>>> https://forum.dlang.org/post/rtarlodeojnmedgsnscb@forum.dlang.org
>>> 
>>> But so far(DMD32 D Compiler v2.070.2) it's still not fixed.
>>> Do you think it will be fixed one day ?
>>> 
>>> Thanks
>>
>> Yes, I think it will be fixed one day, since - as you know
>> by reading the very thread you linked - it is already reported
>> and the GDC developers chimed in and considered it critical.
>> There are also 118 open critical/blocker bugs that were
>> reported before yours. Most of them by people here on the
>> forums and you would need to explain to us why your bug
>> deserves higher attention than the others (154 in total).
>>
>> Dlang is free open-source software and there is only a hand 
>> full of people who are fixing bugs in the compiler just for 
>> the sake of improving it. Most people contribute occasionally 
>> when they are interested in a solution to a particular problem.
>>
>> If you really need this fixed now ... you know the drill. I 
>> suggest you analyze the problem and start a discussion about 
>> it. Honestly asking why the compiler emits duplicate symbols 
>> in a reduced test case might have yielded you some good 
>> responses from the people who wrote the code.
>
> Ok first maybe it's already reported to GDC but to me it's not 
> only a gdc bug since it also happens with dmd. So I don't know 
> how bugs are fixed in the differents compilers but I suppose 
> they share the same frontend (maybe I am mistaken) and in this 
> case I prefer not to wait for gdc developers to fix it but to 
> see if for instance some dmd developers have some time to fix 
> it.
> I just want to use the language and don't have time to dig 
> inside its inner workings, so I think D is not for me. This 
> project was the opportunity to learn the language by fixing an 
> unmaintained library (wxD) but it's not as easy as I thought.

What may speed-up bug fixing a lot is preparing a nice testcase 
that is *as small as possible*.
As you can see in the bug report [1], there is already a 
testcase. It is a good start, but it is not very minimal: 
contains a lot of comments etc. That is a lot of distraction / 
bother (for me at least). One way to help here is to minimize it 
further, and distill it down to the essential thing that appears 
to trigger the bug. You can do that without knowing any compiler 
internals.
It can be very time consuming to make such a testcase, which may 
discourage developers fixing of your bug.

[1] https://issues.dlang.org/show_bug.cgi?id=15324