This seems like a very simple concept when compared with other systems using software transplants [1]. The most important thing I gleaned from this is the benefit of having 'type information' (clojure specs) available as first class data. The reason why this is so simple, which isn't a bad thing, is because clojure (and lisps) makes it easy to get metadata and work with it.

[1] http://crest.cs.ucl.ac.uk/autotransplantation/downloads/auto...