Fixes to propagate_positions

lark/parse_tree_builder.py

@@ -29,7 +29,7 @@ class PropagatePositions:
 
         if isinstance(res, Tree):
             for c in children:
-                if isinstance(c, Tree) and c.children and not c.meta.empty:
+                if isinstance(c, Tree) and not c.meta.empty:
                     res.meta.line = c.meta.line
                     res.meta.column = c.meta.column
                     res.meta.start_pos = c.meta.start_pos
@@ -43,7 +43,7 @@ class PropagatePositions:
                     break
 
             for c in reversed(children):
-                if isinstance(c, Tree) and c.children and not c.meta.empty:
+                if isinstance(c, Tree) and not c.meta.empty:
                     res.meta.end_line = c.meta.end_line
                     res.meta.end_column = c.meta.end_column
                     res.meta.end_pos = c.meta.end_pos

tests/__main__.py

@@ -10,7 +10,7 @@ from .test_reconstructor import TestReconstructor
 try:
     from .test_nearley.test_nearley import TestNearley
 except ImportError:
-    logging.warn("Warning: Skipping tests for Nearley (js2py required)")
+    logging.warning("Warning: Skipping tests for Nearley grammar imports (js2py required)")
 
 # from .test_selectors import TestSelectors
 # from .test_grammars import TestPythonG, TestConfigG

tests/test_parser.py

@@ -63,6 +63,14 @@ class TestParsers(unittest.TestCase):
         r = g.parse('a')
         self.assertEqual( r.children[0].meta.line, 1 )
 
+        g = Lark("""start: x
+                    x: a
+                    a: "a"
+                 """, propagate_positions=True)
+
+        r = g.parse('a')
+        self.assertEqual( r.children[0].meta.line, 1 )
+
     def test_expand1(self):
 
         g = Lark("""start: a