failing test for pattern matching on patterns

idea/testData/codegen/patternMatching/pattern.jet

@@ -0,0 +1,4 @@
+fun isString(x: Any) = when(x) {
+  is String => "string"
+  else => "something"
+}

idea/tests/org/jetbrains/jet/codegen/PatternMatchingTest.java

@@ -34,4 +34,11 @@ public class PatternMatchingTest extends CodegenTestCase {
         }
         assertTrue(caught);
     }
+
+    public void _testPattern() throws Exception {
+        loadFile();
+        Method foo = generateFunction();
+        assertEquals("string", foo.invoke(null, ""));
+        assertEquals("something", foo.invoke(null, new Object()));
+    }
 }