Fix inference for overloaded __call__ with generic self (#16053)

Fixes #8283

Co-authored-by: ilevkivskyi

Author: hauntsaninja

mypy/checkexpr.py

@@ -1475,6 +1475,7 @@ def check_call(
         callable_node: Expression | None = None,
         callable_name: str | None = None,
         object_type: Type | None = None,
+        original_type: Type | None = None,
     ) -> tuple[Type, Type]:
         """Type check a call.
 
@@ -1537,7 +1538,7 @@ def check_call(
                 is_super=False,
                 is_operator=True,
                 msg=self.msg,
-                original_type=callee,
+                original_type=original_type or callee,
                 chk=self.chk,
                 in_literal_context=self.is_literal_context(),
             )
@@ -1578,6 +1579,7 @@ def check_call(
                 callable_node,
                 callable_name,
                 object_type,
+                original_type=callee,
             )
         else:
             return self.msg.not_callable(callee, context), AnyType(TypeOfAny.from_error)

mypy/checkmember.py

@@ -331,13 +331,12 @@ def analyze_instance_member_access(
             signature = method.type
         signature = freshen_all_functions_type_vars(signature)
         if not method.is_static:
-            if name != "__call__":
-                # TODO: use proper treatment of special methods on unions instead
-                #       of this hack here and below (i.e. mx.self_type).
-                dispatched_type = meet.meet_types(mx.original_type, typ)
-                signature = check_self_arg(
-                    signature, dispatched_type, method.is_class, mx.context, name, mx.msg
-                )
+            # TODO: use proper treatment of special methods on unions instead
+            #       of this hack here and below (i.e. mx.self_type).
+            dispatched_type = meet.meet_types(mx.original_type, typ)
+            signature = check_self_arg(
+                signature, dispatched_type, method.is_class, mx.context, name, mx.msg
+            )
             signature = bind_self(signature, mx.self_type, is_classmethod=method.is_class)
         # TODO: should we skip these steps for static methods as well?
         # Since generic static methods should not be allowed.

mypy/subtypes.py

@@ -454,19 +454,22 @@ def visit_instance(self, left: Instance) -> bool:
                     if isinstance(unpacked, Instance):
                         return self._is_subtype(left, unpacked)
             if left.type.has_base(right.partial_fallback.type.fullname):
-                # Special case to consider Foo[*tuple[Any, ...]] (i.e. bare Foo) a
-                # subtype of Foo[<whatever>], when Foo is user defined variadic tuple type.
-                mapped = map_instance_to_supertype(left, right.partial_fallback.type)
-                if len(mapped.args) == 1 and isinstance(mapped.args[0], UnpackType):
-                    unpacked = get_proper_type(mapped.args[0].type)
-                    if isinstance(unpacked, Instance):
-                        assert unpacked.type.fullname == "builtins.tuple"
-                        if isinstance(get_proper_type(unpacked.args[0]), AnyType):
-                            return not self.proper_subtype
-                if mapped.type.fullname == "builtins.tuple" and isinstance(
-                    get_proper_type(mapped.args[0]), AnyType
-                ):
-                    return not self.proper_subtype
+                if not self.proper_subtype:
+                    # Special case to consider Foo[*tuple[Any, ...]] (i.e. bare Foo) a
+                    # subtype of Foo[<whatever>], when Foo is user defined variadic tuple type.
+                    mapped = map_instance_to_supertype(left, right.partial_fallback.type)
+                    for arg in map(get_proper_type, mapped.args):
+                        if isinstance(arg, UnpackType):
+                            unpacked = get_proper_type(arg.type)
+                            if not isinstance(unpacked, Instance):
+                                break
+                            assert unpacked.type.fullname == "builtins.tuple"
+                            if not isinstance(get_proper_type(unpacked.args[0]), AnyType):
+                                break
+                        elif not isinstance(arg, AnyType):
+                            break
+                    else:
+                        return True
             return False
         if isinstance(right, TypeVarTupleType):
             # tuple[Any, ...] is like Any in the world of tuples (see special case above).
@@ -534,15 +537,19 @@ def visit_instance(self, left: Instance) -> bool:
                     right_args = (
                         right_prefix + (TupleType(list(right_middle), fallback),) + right_suffix
                     )
-                    if len(t.args) == 1 and isinstance(t.args[0], UnpackType):
-                        unpacked = get_proper_type(t.args[0].type)
-                        if isinstance(unpacked, Instance):
-                            assert unpacked.type.fullname == "builtins.tuple"
-                            if (
-                                isinstance(get_proper_type(unpacked.args[0]), AnyType)
-                                and not self.proper_subtype
-                            ):
-                                return True
+                    if not self.proper_subtype:
+                        for arg in map(get_proper_type, t.args):
+                            if isinstance(arg, UnpackType):
+                                unpacked = get_proper_type(arg.type)
+                                if not isinstance(unpacked, Instance):
+                                    break
+                                assert unpacked.type.fullname == "builtins.tuple"
+                                if not isinstance(get_proper_type(unpacked.args[0]), AnyType):
+                                    break
+                            elif not isinstance(arg, AnyType):
+                                break
+                        else:
+                            return True
                     type_params = zip(left_args, right_args, right.type.defn.type_vars)
                 else:
                     type_params = zip(t.args, right.args, right.type.defn.type_vars)

test-data/unit/check-overloading.test

@@ -6650,3 +6650,27 @@ def d(x: int) -> int: ...
 def d(f: int, *, x: int) -> str: ...
 def d(*args, **kwargs): ...
 [builtins fixtures/tuple.pyi]
+
+[case testOverloadCallableGenericSelf]
+from typing import Any, TypeVar, Generic, overload, reveal_type
+
+T = TypeVar("T")
+
+class MyCallable(Generic[T]):
+    def __init__(self, t: T):
+        self.t = t
+
+    @overload
+    def __call__(self: "MyCallable[int]") -> str: ...
+    @overload
+    def __call__(self: "MyCallable[str]") -> int: ...
+    def __call__(self): ...
+
+c = MyCallable(5)
+reveal_type(c)  # N: Revealed type is "__main__.MyCallable[builtins.int]"
+reveal_type(c())  # N: Revealed type is "builtins.str"
+
+c2 = MyCallable("test")
+reveal_type(c2)  # N: Revealed type is "__main__.MyCallable[builtins.str]"
+reveal_type(c2()) # should be int  # N: Revealed type is "builtins.int"
+[builtins fixtures/tuple.pyi]

test-data/unit/check-tuples.test

@@ -1434,7 +1434,21 @@ def foo(o: CallableTuple) -> int:
 class CallableTuple(Tuple[str, int]):
     def __call__(self, n: int, m: int) -> int:
         return n
+[builtins fixtures/tuple.pyi]
+
+[case testTypeTupleGenericCall]
+from typing import Generic, Tuple, TypeVar
+
+T = TypeVar('T')
 
+def foo(o: CallableTuple[int]) -> int:
+    reveal_type(o)  # N: Revealed type is "Tuple[builtins.str, builtins.int, fallback=__main__.CallableTuple[builtins.int]]"
+    reveal_type(o.count(3))  # N: Revealed type is "builtins.int"
+    return o(1, 2)
+
+class CallableTuple(Tuple[str, T]):
+    def __call__(self, n: int, m: int) -> int:
+        return n
 [builtins fixtures/tuple.pyi]
 
 [case testTupleCompatibleWithSequence]