The ability to help deliver better compilers.

How you demonstrate that can be in a variety of ways. Any of those would probably be helpful if you can get the right person to notice them.

Having written one or more compilers, or large parts thereof. Obvious bootstrap problem notwithstanding..

Degree in CS, ideally with a thesis on the field.

This is the real answer, it's a huge career risk to make compilers your niche unless you have an academic background in it. The gatekeepers in most CS specialties are really good, and there's an attitude that if you're not at least pursuing a doctorate/working on a big Google project then you're probably a charlatan.

Meh. No doubt there are snobs in the field, but in my experience most of the grit and innovation tends to come from solid engineers without a language/compiler focus, let alone the phd.

> Github repo full of parsers?

Definitely not that one.

Could be a C++ parser