diff --git a/src/main/java/com/android/tools/r8/shaking/TreePruner.java b/src/main/java/com/android/tools/r8/shaking/TreePruner.java
index 0400670..1d57ddf 100644
--- a/src/main/java/com/android/tools/r8/shaking/TreePruner.java
+++ b/src/main/java/com/android/tools/r8/shaking/TreePruner.java
@@ -107,8 +107,8 @@
   }
 
   private boolean isAttributeReferencingPrunedType(InnerClassAttribute attr) {
-    return !appInfo.liveTypes.contains(attr.getInner())
-        || !appInfo.liveTypes.contains(attr.getOuter());
+    return (attr.getInner() != null && !appInfo.liveTypes.contains(attr.getInner()))
+        || (attr.getOuter() != null && !appInfo.liveTypes.contains(attr.getOuter()));
   }
 
   private <S extends PresortedComparable<S>, T extends KeyedDexItem<S>> int firstUnreachableIndex(