diff a/test/langtools/tools/javac/reflect/TestUnsupported.java b/test/langtools/tools/javac/reflect/TestUnsupported.java
--- /dev/null
+++ b/test/langtools/tools/javac/reflect/TestUnsupported.java
@@ -0,0 +1,17 @@
+/*
+ * @test /nodynamiccopyright/
+ * @modules jdk.incubator.code
+ * @ignore there's no more unsupported AST features
+ * @summary Test that unsupported langauge features don't crash javac
+ * @compile/fail/ref=TestUnsupported.out -Werror -Xlint:-incubating -XDrawDiagnostics TestUnsupported.java
+ */
+import jdk.incubator.code.Reflect;
+
+public class TestUnsupported {
+    @Reflect
+    boolean m(Object o) {
+        return switch (o) {
+            case null, default -> true;
+        };
+    }
+}