cl-adams/adams

diff --git a/core/defs.lisp b/core/defs.lisp
index cf6fbf4..064f98f 100644
--- a/core/defs.lisp
+++ b/core/defs.lisp
@@ -252,7 +252,7 @@
   ((property :initarg :property)))
 
 (define-condition resource-operation-failed (resource-operation-error)
-  ((operation :initarg :operation)
+  ((operation :initarg :operation :type operation)
    (diff :initarg :diff)))
 
 ;;  Operators on property lists