diff --git a/contrib/check-code.py b/contrib/check-code.py
--- a/contrib/check-code.py
+++ b/contrib/check-code.py
@@ -288,6 +288,7 @@ pypats = [
     (r'\b__bool__\b', "__bool__ should be __nonzero__ in Python 2"),
     (r'os\.path\.join\(.*, *(""|\'\')\)',
      "use pathutil.normasprefix(path) instead of os.path.join(path, '')"),
+    (r'\s0[0-7]+\b', 'legacy octal syntax; use "0o" prefix instead of "0"'),
   ],
   # warnings
   [