Fix crash related with __getattr__ and __call__ (python#7446)

onlined · ilevkivskyi · commit 125ef0ddaa92 · 2019-09-15T15:15:44.000+01:00
Fixes python#7243.
diff --git a/mypy/checker.py b/mypy/checker.py
@@ -3808,12 +3808,12 @@ def check_subtype(self, subtype: Type, supertype: Type, context: Context,
                 isinstance(subtype, (Instance, TupleType, TypedDictType))):
             self.msg.report_protocol_problems(subtype, supertype, context, code=code)
         if isinstance(supertype, CallableType) and isinstance(subtype, Instance):
-            call = find_member('__call__', subtype, subtype)
+            call = find_member('__call__', subtype, subtype, is_operator=True)
             if call:
                 self.msg.note_call(subtype, call, context, code=code)
         if isinstance(subtype, (CallableType, Overloaded)) and isinstance(supertype, Instance):
             if supertype.type.is_protocol and supertype.type.protocol_members == ['__call__']:
-                call = find_member('__call__', supertype, subtype)
+                call = find_member('__call__', supertype, subtype, is_operator=True)
                 assert call is not None
                 self.msg.note_call(supertype, call, context, code=code)
         return False
@@ -4072,7 +4072,7 @@ def iterable_item_type(self, instance: Instance) -> Type:
             # in case there is no explicit base class.
             return item_type
         # Try also structural typing.
-        iter_type = get_proper_type(find_member('__iter__', instance, instance))
+        iter_type = get_proper_type(find_member('__iter__', instance, instance, is_operator=True))
         if iter_type and isinstance(iter_type, CallableType):
             ret_type = get_proper_type(iter_type.ret_type)
             if isinstance(ret_type, Instance):
diff --git a/mypy/constraints.py b/mypy/constraints.py
@@ -285,7 +285,8 @@ def visit_instance(self, template: Instance) -> List[Constraint]:
                 if not any(mypy.sametypes.is_same_type(template, t)
                            for t in template.type.inferring):
                     template.type.inferring.append(template)
-                    call = mypy.subtypes.find_member('__call__', template, actual)
+                    call = mypy.subtypes.find_member('__call__', template, actual,
+                                                     is_operator=True)
                     assert call is not None
                     if mypy.subtypes.is_subtype(actual, erase_typevars(call)):
                         subres = infer_constraints(call, actual, self.direction)
@@ -430,7 +431,8 @@ def visit_callable_type(self, template: CallableType) -> List[Constraint]:
         elif isinstance(self.actual, Instance):
             # Instances with __call__ method defined are considered structural
             # subtypes of Callable with a compatible signature.
-            call = mypy.subtypes.find_member('__call__', self.actual, self.actual)
+            call = mypy.subtypes.find_member('__call__', self.actual, self.actual,
+                                             is_operator=True)
             if call:
                 return infer_constraints(template, call, self.direction)
             else:
diff --git a/mypy/join.py b/mypy/join.py
@@ -468,5 +468,5 @@ def join_type_list(types: List[Type]) -> Type:
 def unpack_callback_protocol(t: Instance) -> Optional[Type]:
     assert t.type.is_protocol
     if t.type.protocol_members == ['__call__']:
-        return find_member('__call__', t, t)
+        return find_member('__call__', t, t, is_operator=True)
     return None
diff --git a/mypy/messages.py b/mypy/messages.py
@@ -507,7 +507,8 @@ def incompatible_argument_note(self,
             self.report_protocol_problems(original_caller_type, callee_type, context, code=code)
         if (isinstance(callee_type, CallableType) and
                 isinstance(original_caller_type, Instance)):
-            call = find_member('__call__', original_caller_type, original_caller_type)
+            call = find_member('__call__', original_caller_type, original_caller_type,
+                               is_operator=True)
             if call:
                 self.note_call(original_caller_type, call, context, code=code)
 
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
@@ -229,7 +229,7 @@ def visit_instance(self, left: Instance) -> bool:
                     return is_named_instance(item, 'builtins.object')
         if isinstance(right, CallableType):
             # Special case: Instance can be a subtype of Callable.
-            call = find_member('__call__', left, left)
+            call = find_member('__call__', left, left, is_operator=True)
             if call:
                 return self._is_subtype(call, right)
             return False
@@ -258,7 +258,7 @@ def visit_callable_type(self, left: CallableType) -> bool:
             if right.type.is_protocol and right.type.protocol_members == ['__call__']:
                 # OK, a callable can implement a protocol with a single `__call__` member.
                 # TODO: we should probably explicitly exclude self-types in this case.
-                call = find_member('__call__', right, left)
+                call = find_member('__call__', right, left, is_operator=True)
                 assert call is not None
                 if self._is_subtype(left, call):
                     return True
@@ -345,7 +345,7 @@ def visit_overloaded(self, left: Overloaded) -> bool:
         if isinstance(right, Instance):
             if right.type.is_protocol and right.type.protocol_members == ['__call__']:
                 # same as for CallableType
-                call = find_member('__call__', right, left)
+                call = find_member('__call__', right, left, is_operator=True)
                 assert call is not None
                 if self._is_subtype(left, call):
                     return True
@@ -521,7 +521,10 @@ def f(self) -> A: ...
     return True
 
 
-def find_member(name: str, itype: Instance, subtype: Type) -> Optional[Type]:
+def find_member(name: str,
+                itype: Instance,
+                subtype: Type,
+                is_operator: bool = False) -> Optional[Type]:
     """Find the type of member by 'name' in 'itype's TypeInfo.
 
     Fin the member type after applying type arguments from 'itype', and binding
@@ -549,7 +552,8 @@ def find_member(name: str, itype: Instance, subtype: Type) -> Optional[Type]:
             v = v.var
         if isinstance(v, Var):
             return find_node_type(v, itype, subtype)
-        if not v and name not in ['__getattr__', '__setattr__', '__getattribute__']:
+        if (not v and name not in ['__getattr__', '__setattr__', '__getattribute__'] and
+                not is_operator):
             for method_name in ('__getattribute__', '__getattr__'):
                 # Normally, mypy assumes that instances that define __getattr__ have all
                 # attributes with the corresponding return type. If this will produce
@@ -1167,7 +1171,7 @@ def check_argument(leftarg: Type, rightarg: Type, variance: int) -> bool:
                 return True
             return False
         if isinstance(right, CallableType):
-            call = find_member('__call__', left, left)
+            call = find_member('__call__', left, left, is_operator=True)
             if call:
                 return self._is_proper_subtype(call, right)
             return False
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
@@ -2511,6 +2511,28 @@ class A:
 a = A()
 a.y()  # E: "A" not callable
 
+[case testGetattrWithCallable]
+from typing import Callable, Any
+
+class C:
+    def __getattr__(self, attr: str) -> C: ...
+
+def do(cd: Callable[..., Any]) -> None: ...
+
+do(C())  # E: Argument 1 to "do" has incompatible type "C"; expected "Callable[..., Any]"
+
+[case testGetattrWithCallableTypeVar]
+from typing import Callable, Any, TypeVar
+
+class C:
+    def __getattr__(self, attr: str) -> C: ...
+
+T = TypeVar('T', bound=Callable[..., Any])
+
+def do(cd: T) -> T: ...
+
+do(C())  # E: Value of type variable "T" of "do" cannot be "C"
+
 [case testNestedGetattr]
 def foo() -> object:
     def __getattr__() -> None:  # no error because not in a class
