Undefined symbol for, apparently, valid code?

[unleashy via Digitalmars-d-learn]

On Thursday, 6 July 2017 at 16:16:17 UTC, H. S. Teoh wrote:
> Which version of the compiler are you using?  I just tested on 
> the latest dmd git HEAD, and it (correctly) tells me that it's 
> illegal to override a non-virtual function.  I'm surprised you 
> got your code to compile at all.

`dmd --version` outputs:

---
DMD32 D Compiler v2.074.1
Copyright (c) 1999-2017 by Digital Mars written by Walter Bright
---

I downloaded it 3 days ago, for Windows. It's not git HEAD, but 
it's the one available for download in the homepage. Thankfully, 
it seems fixed for the next version then?