Understanding SIGSEGV issues

[Nicholas Wilson]

On Thursday, 3 January 2019 at 06:25:46 UTC, Russel Winder wrote:
> So I have a D program that used to work. I come back to it, 
> recompile it, and:
>
> [...]

> __GI___libc_free (mem=0xa) at malloc.c:3093

You've tried to free a pointer that, while not null, was derived 
from a pointer that was, i.e. an offset to a field of a struct.

A backtrace would help a lot, otherwise it really is just 
guessing.