fix(optional_dereference): suppress zero-arg .get() false positives

dict.get() requires at least one positional key argument; .get() with no
arguments is always a custom class method (e.g. Twisted DeferredQueue.get(),
stats collector .get()). The prior guard only short-circuited the kwargs-only
case (Django ORM pattern), leaving bare .get() calls incorrectly flagged.

Regression: jasmin/managers/clients.py DeferredQueue pattern.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Your Name

failure_mode.py

@@ -230,6 +230,11 @@ def visit_Assign(self, node):
                     # dict.get() is never called on a chained method result.
                     if isinstance(recv, _ast.Call):
                         return
+                    # Zero-arg .get() — dict.get() requires at least one positional
+                    # arg (the key); a bare .get() call is a custom class method
+                    # (e.g. Twisted DeferredQueue.get(), stats collector .get()).
+                    if not call_args and not node.value.keywords:
+                        return
                     # Django ORM queryset.get(**kwargs) — no positional args, only
                     # keyword field lookups like .get(pk=1) or .get(user=user).
                     # dict.get() ALWAYS takes a positional key; kwargs-only means ORM.

test_checker.py

@@ -1927,3 +1927,24 @@ async def main(urls):
     violations = check_codebase(tmp_path)
     ma = [v for v in violations if v.context == "missing_await" and "direct_gather.py" in v.file]
     assert len(ma) == 0, f"Expected 0 missing_await for starred comprehension, got {len(ma)}: {[(v.line, v.call) for v in ma]}"
+
+
+def test_optional_dereference_zero_arg_get_not_flagged(tmp_path):
+    """obj.get() with no args is a custom method (e.g. Twisted DeferredQueue), not dict.get().
+    dict.get() always requires at least one positional key argument."""
+    _write_src(
+        tmp_path,
+        "twisted_queue.py",
+        """
+        class DeferredQueue:
+            def get(self):
+                return Deferred()
+
+        def process(queue):
+            d = queue.get()
+            d.addCallback(handler)
+        """,
+    )
+    violations = check_codebase(tmp_path)
+    od = [v for v in violations if v.context == "optional_dereference" and "twisted_queue.py" in v.file]
+    assert len(od) == 0, f"Expected 0 optional_dereference for zero-arg .get(), got {len(od)}: {[(v.line, v.call) for v in od]}"