Java: More nullness qltests.

Author: aschackmull

java/ql/test/query-tests/Nullness/B.java

@@ -471,4 +471,29 @@ public void loopCorrTest2(boolean[] a) {
       }
     }
   }
+
+  public void loopCorrTest3(String[] ss) {
+    Object x = null;
+    Object t = null;
+    for (String s : ss) {
+      if (t == null) {
+        t = s;
+      } else {
+        if (t instanceof String) {
+          x = new Object();
+          t = new Object();
+        }
+        // correctly guarded by t: null -> String -> Object
+        x.hashCode(); // Spurious NPE - false positive
+      }
+    }
+  }
+
+  public void initCorr(boolean b) {
+    Object o2 = b ? null : "";
+    if (b)
+      o2 = "";
+    else
+      o2.hashCode(); // OK
+  }
 }

java/ql/test/query-tests/Nullness/NullMaybe.expected

@@ -20,6 +20,7 @@
 | B.java:408:7:408:7 | x | Variable $@ may be null at this access as suggested by $@ null guard. | B.java:374:23:374:30 | x | x | B.java:375:23:375:31 | ... != ... | this |
 | B.java:448:9:448:9 | x | Variable $@ may be null at this access because of $@ assignment. | B.java:442:5:442:28 | Object x | x | B.java:446:9:446:16 | ...=... | this |
 | B.java:465:9:465:9 | x | Variable $@ may be null at this access because of $@ assignment. | B.java:458:5:458:28 | Object x | x | B.java:470:9:470:16 | ...=... | this |
+| B.java:487:9:487:9 | x | Variable $@ may be null at this access because of $@ assignment. | B.java:476:5:476:20 | Object x | x | B.java:476:12:476:19 | x | this |
 | C.java:9:44:9:45 | a2 | Variable $@ may be null at this access as suggested by $@ null guard. | C.java:6:5:6:23 | long[][] a2 | a2 | C.java:7:34:7:54 | ... != ... | this |
 | C.java:9:44:9:45 | a2 | Variable $@ may be null at this access because of $@ assignment. | C.java:6:5:6:23 | long[][] a2 | a2 | C.java:6:14:6:22 | a2 | this |
 | C.java:10:17:10:18 | a3 | Variable $@ may be null at this access as suggested by $@ null guard. | C.java:8:5:8:21 | long[] a3 | a3 | C.java:9:38:9:58 | ... != ... | this |