with-redefs gotcha

gistfile1.md

user=> (defn hello [] "hello")
#'user/hello
user=> (defn goodbye [] "goodbye")
#'user/goodbye
user=> (let [f hello]
         (with-redefs [hello goodbye]
           (f)))
"hello"
user=> (with-redefs [hello goodbye]
         (let [f hello]
           (f)))
"goodbye"