diff -r 88502b1cf76f -r 7799a51dbe30 test/langtools/tools/javac/patterns/CastConversionMatch.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/tools/javac/patterns/CastConversionMatch.java	Wed Nov 27 09:00:01 2019 +0100
@@ -0,0 +1,18 @@
+/*
+ * @test /nodynamicopyright/
+ * @bug 8231827
+ * @summary Match which involves a cast conversion
+ * @compile/fail/ref=CastConversionMatch.out -XDrawDiagnostics --enable-preview -source ${jdk.version} CastConversionMatch.java
+ */
+
+public class CastConversionMatch {
+    public static void main(String [] args) {
+        Object o = 42;
+        if (o instanceof int s) {
+            System.out.println("Okay");
+        } else {
+            throw new AssertionError("broken");
+        }
+        System.out.println(">Test complete");
+    }
+}