[AryanRG]

Summary

Recognize the target of an unparenthesized assignment expression in a call argument as a definition. Previously, parso.parse('f(target := source)').get_used_names()['target'][0].get_definition() returned None, while the parenthesized form worked.

The change only classifies the left-hand target of a direct argument node; right-hand references and ordinary keyword arguments retain their existing behavior. It also allows existing syntax checks that depend on definition classification to match Python's treatment of these assignments.

Validation

• New regression and control cases cover seven grammar versions (3.8–3.14): 56 cases fail on the base, and all 105 focused cases pass with this patch.
• Full local suite: 2,094 passed on Python 3.12.15.
• Flake8, Zuban, and whitespace checks passed. Other interpreter runtimes, external consumers, and hosted CI remain unverified.

Prepared with AI assistance; regression tests and the full suite were run locally.