I'm learning, so no idea if this is known or what causes the segfault.

Linux
DMD64 D Compiler v2.078.3

```
void main()
{
	import std.stdio;
	
	{
		class C
		{
			int i;
		}
	}
	{
		class C
		{
			int i;
		}
		C c1 = new C();
		c1.i++;          // no segfault without this line
		C c2 = c1;
	}
}
```

dmd -run test.d
test.d(12): Error: declaration C is already defined in another scope in main
test.d(16): Error: class C no size because of forward reference
test.d(12): Error: class C is forward referenced when looking for 'i'
test.d(12): Error: class C is forward referenced when looking for 'i'
test.d(12): Error: class C is forward referenced when looking for 'opDot'
test.d(12): Error: class C is forward referenced when looking for 'opDispatch'
Segmentation fault (core dumped)

On Thursday, March 29, 2018 20:48:47 number via Digitalmars-d wrote:
> I'm learning, so no idea if this is known or what causes the segfault.

If you cannot find the issue https://issues.dlang.org, then report it. Worst case, if there was a matching report that you missed, then the new issue will be closed as a duplicate. Either way, the compiler should never segfault.

- Jonathan M Davis

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

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

the provoking line is commented out in that snippet. when commented in, all compilers give the segfault, including ldc ones. except for 'all dmd compilers..' with version <= 2.066.0

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.