PEP 758 changes do not have `CHECK_VERSION` guard for usage with `ast.parse(..., feature_version=(3, 13))`

[sobolevn]

Bug report

Right now this test passes:

    def test_pep758_except_without_parens(self):
        code = textwrap.dedent("""
            try:
                ...
            except ValueError, TypeError:
                ...
        """)
        ast.parse(code, feature_version=(3, 14))
        with self.assertRaises(SyntaxError):
            ast.parse(code, feature_version=(3, 13))

But, it should not pass. I have a PR ready.

Linked PRs

• gh-133194: Add CHECK_VERSION to new PEP758 grammar #133195
• gh-133194: Fix regression with PEP 758 parsing on older feature_version #133289

[cdce8p]

The fix in #133195 broke valid cases. E.g.

import ast
import textwrap

code = textwrap.dedent("""
    try:
        ...
    except ValueError:
        ...
""")
ast.parse(code, feature_version=(3, 10))

now also raises a SyntaxError.

[sobolevn]

@sobolevn oups, indeed. thanks for noticing. working on a fix