D Compiler Bug?

[Bottled Gin]

I am using LDC-1.14-beta1, but tried with LDC-1.12 as well. This 
bug totally freaked me out. It took me over a week to reduce to 
this level from my forty thousand line project (thanks dustmite).

I am compiling a static library and then linking to the file 
having main function. I get assert for a class method which I am 
not calling anywhere. I am posting it in the forum so that I can 
get some help reducing it further. Right now it is < 100 lines, 
but spread over 9 files.

I have put the code on github. -> 
https://github.com/dsnippet/ldcbug

To test, clone the git repo, have LDC in path and make run.

Please help.