D Compiler Bug?

[Bottled Gin]

On Tuesday, 12 February 2019 at 17:23:43 UTC, H. S. Teoh wrote:

> There is no need to worry about branches being deleted; in git, 
> branches are merely references to commits. As long as you have 
> the git repo, you have all the information you need. All you 
> have to do is to identify the branch point of the branch (`git 
> log --graph --oneline` is your friend) and the tip of the 
> branch, and digger should be able to bisect that range to 
> something more manageable.


Thanks Teoh, I was able to move forward using "git bisect" 
manually.

The commit that breaks these tests is:

commit fb315d03f0744b8406d31b9c106d3a42c0c178b3
Author: Walter Bright <walter at walterbright.com>
Date:   Thu Mar 23 23:16:12 2017 -0700

     refactor: move towards using semanticRun

 From the comment and the commits that follow, it is clear that 
this is first in a series of commits, though this commit itself 
is not too many lines of code.

I do not understand what is happening in the code here. So either 
I need help or someone else needs to take this forward from here.