diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/NonCanonicalType.java b/core/src/main/java/com/google/errorprone/bugpatterns/NonCanonicalType.java
index 746e9578253..bfe848bba12 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/NonCanonicalType.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/NonCanonicalType.java
@@ -29,8 +29,9 @@
 import com.google.errorprone.fixes.SuggestedFix;
 import com.google.errorprone.matchers.Description;
 import com.google.errorprone.util.Visibility;
-import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MemberSelectTree;
+import com.sun.source.tree.ParameterizedTypeTree;
+import com.sun.source.tree.Tree;
 import com.sun.tools.javac.code.Symbol;
 import com.sun.tools.javac.code.Symbol.TypeSymbol;
 import com.sun.tools.javac.util.Position;
@@ -115,7 +116,7 @@ private static String createDescription(String canonicalName, String nonCanonica
    * Find the non-canonical name which is being used to refer to this type. We can't just use {@code
    * getSymbol}, given that points to the same symbol as the canonical name.
    */
-  private static String getNonCanonicalName(ExpressionTree tree) {
+  private static String getNonCanonicalName(Tree tree) {
     switch (tree.getKind()) {
       case IDENTIFIER:
         return getSymbol(tree).getQualifiedName().toString();
@@ -128,8 +129,10 @@ private static String getNonCanonicalName(ExpressionTree tree) {
         return getNonCanonicalName(memberSelectTree.getExpression())
             + "."
             + memberSelectTree.getIdentifier();
+      case PARAMETERIZED_TYPE:
+        return getNonCanonicalName(((ParameterizedTypeTree) tree).getType());
       default:
-        throw new AssertionError();
+        throw new AssertionError(tree.getKind());
     }
   }
 }
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/NonCanonicalTypeTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/NonCanonicalTypeTest.java
index be7f46836fc..127bca95cc5 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/NonCanonicalTypeTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/NonCanonicalTypeTest.java
@@ -219,4 +219,27 @@ public void method_noFinding() {
             "}")
         .doTest();
   }
+
+  // TODO(cushon): the fix for this should be Super<?>.Inner, not Super.Inner
+  @Test
+  public void innerArray() {
+    compilationHelper
+        .addSourceLines(
+            "Super.java", //
+            "class Super<T> {",
+            "  class Inner {}",
+            "}")
+        .addSourceLines(
+            "Super.java", //
+            "class Sub<T> extends Super<T> {",
+            "}")
+        .addSourceLines(
+            "Test.java", //
+            "class Test {",
+            "  // BUG: Diagnostic contains: `Super.Inner` was referred to by the non-canonical name"
+                + " `Sub.Inner`",
+            "  Sub<?>.Inner[] x;",
+            "}")
+        .doTest();
+  }
 }