diff --git a/packages/compartment-mapper/src/node-modules.js b/packages/compartment-mapper/src/node-modules.js
index 9f94eb9d5f..10e497297d 100644
--- a/packages/compartment-mapper/src/node-modules.js
+++ b/packages/compartment-mapper/src/node-modules.js
@@ -612,6 +612,12 @@ const translateGraph = (
       policy,
     );
 
+    /* c8 ignore next */
+    if (policy && !packagePolicy) {
+      // this should never happen
+      throw new TypeError('Unexpectedly falsy package policy');
+    }
+
     /**
      * @param {string} dependencyName
      * @param {string} packageLocation