I tried to evaluate a Clojure expression with nested shorthand functions today, and it wouldn't let me.
The expression was:
(#(+ % (#(+ % (* % %)) %)) 5) ; sorry for the eye bleed
The output was:
IllegalStateException Nested #()s are not allowed clojure.lang.LispReader$FnReader.invoke (LispReader.java:630)
...and a bunch of other garbage