diff --git a/src/main/java/org/jenkinsci/plugins/workflow/actions/WarningAction.java b/src/main/java/org/jenkinsci/plugins/workflow/actions/WarningAction.java
index 71f25a63..7979d24c 100644
--- a/src/main/java/org/jenkinsci/plugins/workflow/actions/WarningAction.java
+++ b/src/main/java/org/jenkinsci/plugins/workflow/actions/WarningAction.java
@@ -2,6 +2,7 @@
 
 import hudson.model.Result;
 import javax.annotation.Nonnull;
+import org.jenkinsci.plugins.workflow.graph.FlowNode;
 
 /**
  * This action can be attached to a {@link FlowNode} to signify that some non-fatal