diff --git a/Lib/test/test_symtable.py b/Lib/test/test_symtable.py index bd367c1591c7441..24d89b09d946ad3 100644 --- a/Lib/test/test_symtable.py +++ b/Lib/test/test_symtable.py @@ -528,6 +528,27 @@ def test_symtable_entry_repr(self): self.assertEqual(repr(self.top._table), expected) +class ComprehensionTests(unittest.TestCase): + def get_identifiers_recursive(self, st, res): + res.extend(st.get_identifiers()) + for ch in st.get_children(): + self.get_identifiers_recursive(ch, res) + + def test_loopvar_in_only_one_scope(self): + # ensure that the loop variable appears only once in the symtable + comps = [ + "[x for x in [1]]", + "{x for x in [1]}", + "{x:x*x for x in [1]}", + ] + for comp in comps: + with self.subTest(comp=comp): + st = symtable.symtable(comp, "?", "exec") + ids = [] + self.get_identifiers_recursive(st, ids) + self.assertEqual(len([x for x in ids if x == 'x']), 1) + + class CommandLineTest(unittest.TestCase): maxDiff = None