Java: Add more field-flow tests

Author: hvitved

java/ql/test/library-tests/dataflow/fields/F.java

@@ -0,0 +1,38 @@
+public class F {
+  Object Field1;
+  Object Field2;
+  public F() {
+    Field1 = new Object();
+    Field2 = new Object();
+  }
+
+  private void m() {
+    Object o = new Object();
+    F f = new F();
+    f.Field1 = o;
+    f.Field2 = o;
+    f.Field2 = null;
+    sink(f.Field1); // flow
+    sink(f.Field2); // no flow [FALSE POSITIVE]
+
+    f = new F();
+    f.Field2 = null;
+    sink(f.Field1); // flow
+    sink(f.Field2); // no flow [FALSE POSITIVE]
+
+    f = new F();
+    o = new Object();
+    f.Field1 = o;
+    f.Field2 = o;
+    m2(f);
+  }
+
+  private void m2(F f)
+  {
+    f.Field2 = null;
+    sink(f.Field1); // flow
+    sink(f.Field2); // no flow [FALSE POSITIVE]
+  }
+
+  public static void sink(Object o) { }
+}

java/ql/test/library-tests/dataflow/fields/flow.expected

@@ -26,3 +26,13 @@
 | E.java:2:32:2:43 | new Object(...) | E.java:21:10:21:24 | bh2.buf.content |
 | E.java:2:32:2:43 | new Object(...) | E.java:24:10:24:28 | p2.data.buf.content |
 | E.java:2:32:2:43 | new Object(...) | E.java:30:10:30:27 | p.data.buf.content |
+| F.java:5:14:5:25 | new Object(...) | F.java:15:10:15:17 | f.Field1 |
+| F.java:5:14:5:25 | new Object(...) | F.java:20:10:20:17 | f.Field1 |
+| F.java:5:14:5:25 | new Object(...) | F.java:33:10:33:17 | f.Field1 |
+| F.java:6:14:6:25 | new Object(...) | F.java:16:10:16:17 | f.Field2 |
+| F.java:6:14:6:25 | new Object(...) | F.java:21:10:21:17 | f.Field2 |
+| F.java:6:14:6:25 | new Object(...) | F.java:34:10:34:17 | f.Field2 |
+| F.java:10:16:10:27 | new Object(...) | F.java:15:10:15:17 | f.Field1 |
+| F.java:10:16:10:27 | new Object(...) | F.java:16:10:16:17 | f.Field2 |
+| F.java:24:9:24:20 | new Object(...) | F.java:33:10:33:17 | f.Field1 |
+| F.java:24:9:24:20 | new Object(...) | F.java:34:10:34:17 | f.Field2 |