DataRefNode dataRef = (new ExpressionParser("$boo.0[$foo]")).parseDataReference().getChild(0);
assertFalse(dataRef.isIjDataRef());
assertFalse(dataRef.isNullSafeIjDataRef());
assertEquals("boo", dataRef.getFirstKey());
assertEquals(2, dataRef.numChildren());
DataRefAccessIndexNode access0 = (DataRefAccessIndexNode) dataRef.getChild(0);
assertFalse(access0.isNullSafe());
assertEquals(0, access0.getIndex());
DataRefAccessExprNode access1 = (DataRefAccessExprNode) dataRef.getChild(1);
assertFalse(access1.isNullSafe());
assertEquals("$foo", access1.getChild(0).toSourceString());
dataRef = (new ExpressionParser("$boo?.0?[$foo]")).parseDataReference().getChild(0);
assertFalse(dataRef.isIjDataRef());
assertFalse(dataRef.isNullSafeIjDataRef());
assertEquals("boo", dataRef.getFirstKey());
assertEquals(2, dataRef.numChildren());
access0 = (DataRefAccessIndexNode) dataRef.getChild(0);
assertTrue(access0.isNullSafe());
assertEquals(0, access0.getIndex());
access1 = (DataRefAccessExprNode) dataRef.getChild(1);
assertTrue(access1.isNullSafe());
assertEquals("$foo", access1.getChild(0).toSourceString());
dataRef = (new ExpressionParser("$ij?.boo?.0[$ij.foo]")).parseDataReference().getChild(0);
assertTrue(dataRef.isIjDataRef());
assertTrue(dataRef.isNullSafeIjDataRef());
assertEquals("boo", dataRef.getFirstKey());
assertEquals(2, dataRef.numChildren());
access0 = (DataRefAccessIndexNode) dataRef.getChild(0);
assertTrue(access0.isNullSafe());
assertEquals(0, access0.getIndex());
access1 = (DataRefAccessExprNode) dataRef.getChild(1);
assertFalse(access1.isNullSafe());
DataRefNode childDataRef = (DataRefNode) access1.getChild(0);
assertTrue(childDataRef.isIjDataRef());
assertFalse(childDataRef.isNullSafeIjDataRef());