I have a following config:

{:duct.profile/base
 {:update-organization
  {:organization-client #ig/ref :client}

  :fetch-organization
  {:organization-client #ig/ref :client}

  :client {}

Where client is an instantation of a deftype:

(defmethod ig/init-key :client
  [_ opts]
  (log/info ::client {:opts opts})
  (->OrganizationClient))

This throws the following error:

13:33:21.229 INFO :client {:opts {}}
Execution error (ClassCastException) at duct.core/fold-modules$fn (core.clj:153).
OrganizationClient cannot be cast to clojure.lang.IFn

Any idea why?

Stacktrace:

1. Unhandled java.lang.ClassCastException
   OrganizationClient cannot be cast to clojure.lang.IFn

                  core.clj:  153  duct.core/fold-modules/fn
                 core.cljc:  280  integrant.core$fold$fn__857/invoke
             ArraySeq.java:  116  clojure.lang.ArraySeq/reduce
                  core.clj: 6827  clojure.core/reduce
                  core.clj: 6810  clojure.core/reduce
                 core.cljc:  280  integrant.core$fold/invokeStatic
                 core.cljc:  272  integrant.core$fold/invoke
                  core.clj:  153  duct.core/fold-modules
                  core.clj:  147  duct.core/fold-modules
                  core.clj:  190  duct.core/build-config
                  core.clj:  181  duct.core/build-config
                  core.clj:  201  duct.core/prep-config
                  core.clj:  192  duct.core/prep-config
                   dev.clj:   31  dev/eval19069/fn
                  repl.clj:   16  integrant.repl/prep/fn
                  AFn.java:  154  clojure.lang.AFn/applyToHelper
                  AFn.java:  144  clojure.lang.AFn/applyTo
                  Var.java:  308  clojure.lang.Var/alterRoot
                  core.clj: 5510  clojure.core/alter-var-root
                  core.clj: 5505  clojure.core/alter-var-root
               RestFn.java:  425  clojure.lang.RestFn/invoke
                  repl.clj:   16  integrant.repl/prep
                  repl.clj:   14  integrant.repl/prep
                  repl.clj:   54  integrant.repl/go
                  repl.clj:   53  integrant.repl/go
                      REPL:  484  dev/eval26347
                      REPL:  484  dev/eval26347
             Compiler.java: 7177  clojure.lang.Compiler/eval
             Compiler.java: 7132  clojure.lang.Compiler/eval
                  core.clj: 3214  clojure.core/eval
                  core.clj: 3210  clojure.core/eval
    interruptible_eval.clj:   82  nrepl.middleware.interruptible-eval/evaluate/fn/fn
                  AFn.java:  152  clojure.lang.AFn/applyToHelper
                  AFn.java:  144  clojure.lang.AFn/applyTo
                  core.clj:  665  clojure.core/apply
                  core.clj: 1973  clojure.core/with-bindings*
                  core.clj: 1973  clojure.core/with-bindings*
               RestFn.java:  425  clojure.lang.RestFn/invoke
    interruptible_eval.clj:   82  nrepl.middleware.interruptible-eval/evaluate/fn
                  main.clj:  437  clojure.main/repl/read-eval-print/fn
                  main.clj:  437  clojure.main/repl/read-eval-print
                  main.clj:  458  clojure.main/repl/fn
                  main.clj:  458  clojure.main/repl
                  main.clj:  368  clojure.main/repl
               RestFn.java:  137  clojure.lang.RestFn/applyTo
                  core.clj:  665  clojure.core/apply
                  core.clj:  660  clojure.core/apply
                regrow.clj:   20  refactor-nrepl.ns.slam.hound.regrow/wrap-clojure-repl/fn
               RestFn.java: 1523  clojure.lang.RestFn/invoke
    interruptible_eval.clj:   79  nrepl.middleware.interruptible-eval/evaluate
    interruptible_eval.clj:   56  nrepl.middleware.interruptible-eval/evaluate
    interruptible_eval.clj:  145  nrepl.middleware.interruptible-eval/interruptible-eval/fn/fn
                  AFn.java:   22  clojure.lang.AFn/run
               session.clj:  202  nrepl.middleware.session/session-exec/main-loop/fn
               session.clj:  201  nrepl.middleware.session/session-exec/main-loop
                  AFn.java:   22  clojure.lang.AFn/run
               Thread.java:  748  java.lang.Thread/run

Being cast to fn probably means that there is a non module key outside of the base config

The error is occurring in the fold modules function. Which verifies that

Oh okay so some keys should be outside the base config?

Like the :client

Oh inside

Only module keys should be outside of the base config