Ask HN: Where to start with Swift compiler development?

It deeply urges me to get serious with Swift compiler development, especially after reading https://news.ycombinator.com/item?id=17649301

Do you have any good advice where to start? Does it make sense to start playing with https://github.com/apple/swift/tree/master/lib/Parse ?

Background: No previous experiences with compilers or similar complex topics. All I did so far was building applications with Swift and Python.