diff --git a/src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java b/src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java
index c8e86ee..17510c2 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java
@@ -816,7 +816,7 @@
       }
       if (eligibility.hasMonitorOnReceiver) {
         // We will not be able to remove the monitor instruction afterwards.
-        return null;
+        return false;
       }
     }