Example of error when trying to call a Logger protocol function:

java.lang.IllegalArgumentException: No implementation of method: :enabled? of protocol:
#'clojure.tools.logging.impl/Logger found for class: org.apache.log4j.Logger

The bug is the result of combining syntax-quoting with extend-type, e.g.:

`(do
   (extend-type org.apache.commons.logging.Log
     Logger
     (enabled? [logger# level#] ... )))

The syntax-quote turns the above enabled? into clojure.tools.logging/enabled? protocol function name, and then the extend-type turns that into the keyword :clojure.tools.logging/enabled?, which does not match the expected :enabled?.

Attached patch fixes this by using extend maps rather than extend-type. Also adds some tests.