typing.overload functions are exempted from too-many-function-args

Close #3170

Author: PCManticore

ChangeLog

@@ -41,7 +41,6 @@ Release date: TBA
 
   Close #3148
 
-
 * ``import-outside-toplevel`` is emitted for ``ImportFrom`` nodes as well.
 
   Close #3175
@@ -63,6 +62,10 @@ Release date: TBA
 
   Closes #3185
 
+* ``typing.overload`` functions are exempted from ``too-many-function-args``
+
+  Close #3170
+
 
 What's New in Pylint 2.4.2?
 ===========================

pylint/checkers/typecheck.py

@@ -65,6 +65,7 @@
     is_inside_abstract_class,
     is_iterable,
     is_mapping,
+    is_overload_stub,
     is_super,
     node_ignores_exception,
     safe_infer,
@@ -1185,6 +1186,7 @@ def visit_call(self, node):
 
         num_positional_args = len(call_site.positional_arguments)
         keyword_args = list(call_site.keyword_arguments.keys())
+        overload_function = is_overload_stub(called)
 
         # Determine if we don't have a context for our call and we use variadics.
         node_scope = node.scope()
@@ -1251,11 +1253,12 @@ def visit_call(self, node):
                 # parameter.
                 break
             else:
-                # Too many positional arguments.
-                self.add_message(
-                    "too-many-function-args", node=node, args=(callable_name,)
-                )
-                break
+                if not overload_function:
+                    # Too many positional arguments.
+                    self.add_message(
+                        "too-many-function-args", node=node, args=(callable_name,)
+                    )
+                    break
 
         # 2. Match the keyword arguments.
         for keyword in keyword_args:
@@ -1290,7 +1293,7 @@ def visit_call(self, node):
             elif called.args.kwarg is not None:
                 # The keyword argument gets assigned to the **kwargs parameter.
                 pass
-            else:
+            elif not overload_function:
                 # Unexpected keyword argument.
                 self.add_message(
                     "unexpected-keyword-arg", node=node, args=(keyword, callable_name)
@@ -1315,7 +1318,7 @@ def visit_call(self, node):
                     display_name = "<tuple>"
                 else:
                     display_name = repr(name)
-                if not has_no_context_positional_variadic:
+                if not has_no_context_positional_variadic and not overload_function:
                     self.add_message(
                         "no-value-for-parameter",
                         node=node,

pylint/checkers/utils.py

@@ -753,7 +753,10 @@ def _is_property_decorator(decorator: astroid.Name) -> bool:
     return False
 
 
-def decorated_with(func: astroid.FunctionDef, qnames: Iterable[str]) -> bool:
+def decorated_with(
+    func: Union[astroid.FunctionDef, astroid.BoundMethod, astroid.UnboundMethod],
+    qnames: Iterable[str],
+) -> bool:
     """Determine if the `func` node has a decorator with the qualified name `qname`."""
     decorators = func.decorators.nodes if func.decorators else []
     for decorator_node in decorators:
@@ -1237,9 +1240,8 @@ def is_overload_stub(node: astroid.node_classes.NodeNG) -> bool:
     :param node: Node to check.
     :returns: True if node is an overload function stub. False otherwise.
     """
-    return isinstance(node, astroid.FunctionDef) and decorated_with(
-        node, ["typing.overload"]
-    )
+    decorators = getattr(node, "decorators", None)
+    return bool(decorators and decorated_with(node, ["typing.overload", "overload"]))
 
 
 def is_protocol_class(cls: astroid.node_classes.NodeNG) -> bool:

tests/functional/too/too_many_arguments_overload.py

@@ -0,0 +1,38 @@
+# pylint: disable=missing-function-docstring,missing-module-docstring,missing-class-docstring
+# pylint: disable=too-few-public-methods
+from typing import overload
+
+
+class ClassA:
+    @classmethod
+    @overload
+    def method(cls, arg1):
+        pass
+
+    @classmethod
+    @overload
+    def method(cls, arg1, arg2):
+        pass
+
+    @classmethod
+    def method(cls, arg1, arg2=None):
+        pass
+
+
+ClassA.method(1, 2)
+
+
+class ClassB:
+    @overload
+    def method(self, arg1):
+        pass
+
+    @overload
+    def method(self, arg1, arg2):
+        pass
+
+    def method(self, arg1, arg2=None):
+        pass
+
+
+ClassB().method(1, arg2=2)