one thing I do is have gdb/lldb break on d assert, before it destroys...

...the end by one, so I attached gdb and saw the bug. Yay!

I’m not...

...an x86-64 box I could use gdb if I first take the time to...

...lstdc++ && ./main
Segmentation fault (core dumped)
```

and gdb shows it fails at: main.d:29...

...this, you typically open a debugger like `gdb` and use the `backtrace` command to find...

...reference is coming from.

```
(gdb) p *(void**)0x5eba698
$10 = (void *) 0x5e8aa00
(gdb) p **(void***)0x5eba698...

...the program immediately before the segfault occurs.

```
(gdb) monitor who_points_at 0x5ebb9c8
==1582870== Searching...

...the AST.

---
(gdb) p aa.b[5]
$57 = (dmd.root.aav.aaA *) 0x5efa4a0
(gdb) p...

...in vgdb
---
(gdb) p aa.b
$10 = (dmd.root.aav.aaA **) 0x5ebb990
(gdb) monitor who...

...7442            Type tb = exp.e1.type.toBasetype();
(gdb) bt
#0  ExpressionSemanticVisitor::visit(PtrExp*) (this=0x7fffffff69d8...