diff --git a/src/main/java/com/android/tools/r8/shaking/MainDexListBuilder.java b/src/main/java/com/android/tools/r8/shaking/MainDexListBuilder.java
index b92f82e..b46840b 100644
--- a/src/main/java/com/android/tools/r8/shaking/MainDexListBuilder.java
+++ b/src/main/java/com/android/tools/r8/shaking/MainDexListBuilder.java
@@ -121,7 +121,8 @@
   }
 
   private boolean isEnum(DexType valueType) {
-    return appInfo.isSubtype(valueType, appInfo.dexItemFactory().enumType);
+    return valueType.isClassType()
+        && appInfo.isSubtype(valueType, appInfo.dexItemFactory().enumType);
   }
 
   private boolean isAnnotation(DexType valueType) {