diff --git a/object-watcher/object-watcher/src/main/java/leakcanary/DeletableObjectReporter.kt b/object-watcher/object-watcher/src/main/java/leakcanary/DeletableObjectReporter.kt
index 2f1cdb5ca8..e694bf45b8 100644
--- a/object-watcher/object-watcher/src/main/java/leakcanary/DeletableObjectReporter.kt
+++ b/object-watcher/object-watcher/src/main/java/leakcanary/DeletableObjectReporter.kt
@@ -1,6 +1,6 @@
 package leakcanary
 
-interface DeletableObjectReporter {
+fun interface DeletableObjectReporter {
 
   /**
    * Start tracking the provided [target] object, with the expectation that it should be eligible