fix: Uncaught exception in get_normalizer_issues

parso/python/pep8.py

@@ -444,7 +444,7 @@ def _visit_part(self, part, spacing, leaf):
                         should_be_indentation = n.indentation
 
                         self._last_indentation_tos = n
-                        if n == node:
+                        if n == node or n.parent is None:
                             break
                         n = n.parent
 

tests/test_oss_regression_219.py

@@ -0,0 +1,21 @@
+import parso
+import pytest
+
+
+@pytest.mark.parametrize('newline', ['\n', '\r\n', '\r'])
+def test_comment_after_line_continuation(newline):
+    code = '\\' + newline + '#'
+    grammar = parso.load_grammar()
+    module = grammar.parse(code)
+
+    try:
+        issues = grammar._get_normalizer_issues(module)
+    except AttributeError as error:
+        raise AssertionError(
+            'A comment after a line continuation must not crash normalization'
+        ) from error
+
+    assert [(issue.code, issue.start_pos) for issue in issues] == [
+        (292, (2, 1))
+    ]
+    assert module.get_code() == code