dmd segmentation fault with duplicate class definition

[LiNbO3]

On Thursday, 29 March 2018 at 21:18:02 UTC, Seb wrote:
> On Thursday, 29 March 2018 at 20:48:47 UTC, number wrote:
>> I'm learning, so no idea if this is known or what causes the 
>> segfault.
>>
>> [...]
>
> Always try the latest release when you run into an ICE - 
> chances are very good that it already has been fixed:
>
> https://run.dlang.io/is/OySBGO

There are a couple of bugs here:

---
void main()
{
     { class C { } }
     class C { }
     // C x; x.x=1;
     // static assert (!__traits(compiles, C.x));
}
---

The first bug can be shown by de-commenting the first line and 
can be easily solved by modifying hdrgen.d by adding a check on 
t.sym.parent being non-null to the visit(TypeClass) method.
Once that's fixed de-comment the second line to have the compiler 
crash and burn somewhere else.