diff --git a/mypy/checker.py b/mypy/checker.py index 8973ade98228..b5aff1051645 100644 --- a/mypy/checker.py +++ b/mypy/checker.py @@ -1868,6 +1868,23 @@ def check_method_override_for_base_with_name( original_class_or_static = False # a variable can't be class or static if isinstance(original_type, FunctionLike): + active_self_type = self.scope.active_self_type() + if isinstance(original_type, Overloaded) and active_self_type: + # If we have an overload, filter to overloads that match the self type. + # This avoids false positives for concrete subclasses of generic classes, + # see testSelfTypeOverrideCompatibility for an example. + # It's possible we might want to do this as part of bind_and_map_method + filtered_items = [ + item + for item in original_type.items + if not item.arg_types or is_subtype(active_self_type, item.arg_types[0]) + ] + # If we don't have any filtered_items, maybe it's always a valid override + # of the superclass? However if you get to that point you're in murky type + # territory anyway, so we just preserve the type and have the behaviour match + # that of older versions of mypy. + if filtered_items: + original_type = Overloaded(filtered_items) original_type = self.bind_and_map_method(base_attr, original_type, defn.info, base) if original_node and is_property(original_node): original_type = get_property_type(original_type) diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test index bfb0eb5a4d89..3d801d23a642 100644 --- a/test-data/unit/check-selftype.test +++ b/test-data/unit/check-selftype.test @@ -156,6 +156,92 @@ class B2(A[T]): def f(self: A[bytes]) -> bytes: ... def f(self): ... +class C(A[int]): + def f(self) -> int: ... + +class D(A[str]): + def f(self) -> int: ... # E: Signature of "f" incompatible with supertype "A" \ + # N: Superclass: \ + # N: @overload \ + # N: def f(self) -> str \ + # N: Subclass: \ + # N: def f(self) -> int + +class E(A[T]): + def f(self) -> int: ... # E: Signature of "f" incompatible with supertype "A" \ + # N: Superclass: \ + # N: @overload \ + # N: def f(self) -> int \ + # N: @overload \ + # N: def f(self) -> str \ + # N: Subclass: \ + # N: def f(self) -> int + + +class F(A[bytes]): + # Note there's an argument to be made that this is actually compatible with the supertype + def f(self) -> bytes: ... # E: Signature of "f" incompatible with supertype "A" \ + # N: Superclass: \ + # N: @overload \ + # N: def f(self) -> int \ + # N: @overload \ + # N: def f(self) -> str \ + # N: Subclass: \ + # N: def f(self) -> bytes + +class G(A): + def f(self): ... + +class H(A[int]): + def f(self): ... + +class I(A[int]): + def f(*args): ... + +class J(A[int]): + def f(self, arg) -> int: ... # E: Signature of "f" incompatible with supertype "A" \ + # N: Superclass: \ + # N: @overload \ + # N: def f(self) -> int \ + # N: Subclass: \ + # N: def f(self, arg: Any) -> int + +[builtins fixtures/tuple.pyi] + +[case testSelfTypeOverrideCompatibilityTypeVar-xfail] +from typing import overload, TypeVar, Union + +AT = TypeVar("AT", bound="A") + +class A: + @overload + def f(self: AT, x: int) -> AT: ... + @overload + def f(self, x: str) -> None: ... + @overload + def f(self: AT) -> bytes: ... + def f(*a, **kw): ... + +class B(A): + @overload # E: Signature of "f" incompatible with supertype "A" \ + # N: Superclass: \ + # N: @overload \ + # N: def f(self, x: int) -> B \ + # N: @overload \ + # N: def f(self, x: str) -> None \ + # N: @overload \ + # N: def f(self) -> bytes \ + # N: Subclass: \ + # N: @overload \ + # N: def f(self, x: int) -> B \ + # N: @overload \ + # N: def f(self, x: str) -> None + def f(self, x: int) -> B: ... + @overload + def f(self, x: str) -> None: ... + def f(*a, **kw): ... +[builtins fixtures/dict.pyi] + [case testSelfTypeSuper] from typing import TypeVar, cast