Make FunctionDef.implicit_parameters return 1 for methods (#1531)

ChangeLog

@@ -14,6 +14,11 @@ Release date: TBA
 
 * Fix ``col_offset`` attribute for nodes involving ``with`` on ``PyPy``.
 
+* Made ``FunctionDef.implicit_parameters`` return 1 for methods by making
+  ``FunctionDef.is_bound`` return ``True``, as it does for class methods.
+
+  Closes PyCQA/pylint#6464
+
 * Fixed a crash when ``_filter_stmts`` encounters an ``EmptyNode``.
 
   Closes PyCQA/pylint#6438

astroid/nodes/scoped_nodes/scoped_nodes.py

@@ -1587,6 +1587,9 @@ def blockstart_tolineno(self):
         """
         return self.args.tolineno
 
+    def implicit_parameters(self) -> Literal[0, 1]:
+        return 1 if self.is_bound() else 0
+
     def block_range(self, lineno):
         """Get a range from the given line number to where this node ends.
 
@@ -1648,7 +1651,7 @@ def is_bound(self):
             False otherwise.
         :rtype: bool
         """
-        return self.type == "classmethod"
+        return self.type in {"method", "classmethod"}
 
     def is_abstract(self, pass_is_abstract=True, any_raise_is_abstract=False):
         """Check if the method is abstract.

tests/unittest_brain_qt.py

@@ -16,6 +16,8 @@
 
 @pytest.mark.skipif(HAS_PYQT6 is None, reason="This test requires the PyQt6 library.")
 class TestBrainQt:
+    AstroidManager.brain["extension_package_whitelist"] = {"PyQt6"}
+
     @staticmethod
     def test_value_of_lambda_instance_attrs_is_list():
         """Regression test for https://github.com/PyCQA/pylint/issues/6221
@@ -28,11 +30,25 @@ def test_value_of_lambda_instance_attrs_is_list():
         from PyQt6 import QtPrintSupport as printsupport
         printsupport.QPrintPreviewDialog.paintRequested  #@
         """
-        AstroidManager.brain["extension_package_whitelist"] = {"PyQt6.QtPrintSupport"}
         node = extract_node(src)
         attribute_node = node.inferred()[0]
         if attribute_node is Uninferable:
             pytest.skip("PyQt6 C bindings may not be installed?")
         assert isinstance(attribute_node, UnboundMethod)
         # scoped_nodes.Lambda.instance_attrs is typed as Dict[str, List[NodeNG]]
         assert isinstance(attribute_node.instance_attrs["connect"][0], FunctionDef)
+
+    @staticmethod
+    def test_implicit_parameters() -> None:
+        """Regression test for https://github.com/PyCQA/pylint/issues/6464"""
+        src = """
+        from PyQt6.QtCore import QTimer
+        timer = QTimer()
+        timer.timeout.connect  #@
+        """
+        node = extract_node(src)
+        attribute_node = node.inferred()[0]
+        if attribute_node is Uninferable:
+            pytest.skip("PyQt6 C bindings may not be installed?")
+        assert isinstance(attribute_node, FunctionDef)
+        assert attribute_node.implicit_parameters() == 1

tests/unittest_scoped_nodes.py

@@ -617,6 +617,24 @@ def test():
         self.assertIsInstance(one, nodes.Const)
         self.assertEqual(one.value, 1)
 
+    def test_func_is_bound(self) -> None:
+        data = """
+        class MyClass:
+            def bound():  #@
+                pass
+        """
+        func = builder.extract_node(data)
+        self.assertIs(func.is_bound(), True)
+        self.assertEqual(func.implicit_parameters(), 1)
+
+        data2 = """
+        def not_bound():  #@
+            pass
+        """
+        func2 = builder.extract_node(data2)
+        self.assertIs(func2.is_bound(), False)
+        self.assertEqual(func2.implicit_parameters(), 0)
+
     def test_type_builtin_descriptor_subclasses(self) -> None:
         astroid = builder.parse(
             """