Fix sub_table ordering for nested inlined comprehensions (PEP 709) by LegNeato · Pull Request #7480 · RustPython/RustPython

When an inlined comprehension's first iterator expression contains
nested scopes (such as a lambda), those scopes' sub_tables appear at the
current position in the parent's sub_table list. The previous code
spliced the comprehension's own child sub_tables (e.g. inner inlined
comprehensions) into that same position before compiling the iterator,
which shifted the iterator's sub_tables to wrong indices.

Move the splice after the first iterator is compiled so its sub_tables
are consumed at their original positions.

Fixes nested list comprehensions like:
```python
    [[x for _, x in g] for _, g in itertools.groupby(..., lambda x: ...)]
```

Disclosure: I used AI to develop the patch though I was heavily
involved.

Bot reviewed Mar 22, 2026

LegNeato deleted the fix/nested-comprehension-underscore branch

Copilot AI pushed a commit that referenced this pull request

…7480)

When an inlined comprehension's first iterator expression contains
nested scopes (such as a lambda), those scopes' sub_tables appear at the
current position in the parent's sub_table list. The previous code
spliced the comprehension's own child sub_tables (e.g. inner inlined
comprehensions) into that same position before compiling the iterator,
which shifted the iterator's sub_tables to wrong indices.

Move the splice after the first iterator is compiled so its sub_tables
are consumed at their original positions.

Fixes nested list comprehensions like:
```python
    [[x for _, x in g] for _, g in itertools.groupby(..., lambda x: ...)]
```

Disclosure: I used AI to develop the patch though I was heavily
involved.