Consider Any in selftype when checking overloads

Author: sterliakov

mypy/checkexpr.py

@@ -143,6 +143,7 @@
     validate_instance,
 )
 from mypy.typeops import (
+    bind_self,
     callable_type,
     custom_special_method,
     erase_to_union_or_bound,
@@ -1001,6 +1002,7 @@ def typeddict_callable_from_context(
             self.named_type("builtins.type"),
             variables=variables,
             is_bound=True,
+            original_self_type=AnyType(TypeOfAny.implementation_artifact),
         )
 
     def check_typeddict_call_with_kwargs(
@@ -2911,10 +2913,54 @@ def infer_overload_return_type(
         args_contain_any = any(map(has_any_type, arg_types))
         type_maps: list[dict[Expression, Type]] = []
 
+        # If we have a selftype overload, it should contribute to `any_causes_overload_ambiguity`
+        # check. Pretend that we're checking `Foo.func(instance, ...)` instead of
+        # `instance.func(...)`.
+        p_object_type = get_proper_type(object_type) if object_type is not None else None
+        prepend_self = (
+            isinstance(p_object_type, Instance)
+            and has_any_type(p_object_type)
+            and any(
+                typ.is_bound and typ.original_self_type is not None for typ in plausible_targets
+            )
+        )
+        if prepend_self:
+            assert object_type is not None
+
+            args = [TempNode(object_type)] + args
+            arg_types = [object_type] + arg_types
+            arg_kinds = [ARG_POS] + arg_kinds
+            arg_names = [None, *arg_names] if arg_names is not None else None
+
+        def maybe_bind_self(t: Type) -> Type:
+            if prepend_self and isinstance(t, ProperType) and isinstance(t, FunctionLike):
+                return bind_self(t, object_type)
+            return t
+
         for typ in plausible_targets:
             assert self.msg is self.chk.msg
-            with self.msg.filter_errors() as w:
-                with self.chk.local_type_map as m:
+            with self.msg.filter_errors() as w, self.chk.local_type_map as m:
+                if prepend_self:
+                    param = typ.original_self_type
+                    assert param is not None, "Overload bound only partially?"
+                    assert isinstance(p_object_type, Instance)
+                    param = expand_type_by_instance(param, p_object_type)
+                    ret_type, infer_type = self.check_call(
+                        callee=typ.copy_modified(
+                            arg_types=[param] + typ.arg_types,
+                            arg_kinds=[ARG_POS] + typ.arg_kinds,
+                            arg_names=[None, *typ.arg_names],
+                            is_bound=False,
+                            original_self_type=None,
+                        ),
+                        args=args,
+                        arg_kinds=arg_kinds,
+                        arg_names=arg_names,
+                        context=context,
+                        callable_name=callable_name,
+                        object_type=None,
+                    )
+                else:
                     ret_type, infer_type = self.check_call(
                         callee=typ,
                         args=args,
@@ -2928,9 +2974,9 @@ def infer_overload_return_type(
             if is_match:
                 # Return early if possible; otherwise record info, so we can
                 # check for ambiguity due to 'Any' below.
-                if not args_contain_any:
+                if not args_contain_any and not prepend_self:
                     self.chk.store_types(m)
-                    return ret_type, infer_type
+                    return ret_type, maybe_bind_self(infer_type)
                 p_infer_type = get_proper_type(infer_type)
                 if isinstance(p_infer_type, CallableType):
                     # Prefer inferred types if possible, this will avoid false triggers for
@@ -2949,10 +2995,10 @@ def infer_overload_return_type(
             # We try returning a precise type if we can. If not, we give up and just return 'Any'.
             if all_same_types(return_types):
                 self.chk.store_types(type_maps[0])
-                return return_types[0], inferred_types[0]
+                return return_types[0], maybe_bind_self(inferred_types[0])
             elif all_same_types([erase_type(typ) for typ in return_types]):
                 self.chk.store_types(type_maps[0])
-                return erase_type(return_types[0]), erase_type(inferred_types[0])
+                return erase_type(return_types[0]), maybe_bind_self(erase_type(inferred_types[0]))
             else:
                 return self.check_call(
                     callee=AnyType(TypeOfAny.special_form),
@@ -2966,7 +3012,7 @@ def infer_overload_return_type(
         else:
             # Success! No ambiguity; return the first match.
             self.chk.store_types(type_maps[0])
-            return return_types[0], inferred_types[0]
+            return return_types[0], maybe_bind_self(inferred_types[0])
 
     def overload_erased_call_targets(
         self,
@@ -5017,6 +5063,7 @@ def apply_type_arguments_to_callable(
                         name="tuple",
                         definition=tp.definition,
                         is_bound=tp.is_bound,
+                        original_self_type=tp.original_self_type,
                     )
                 self.msg.incompatible_type_application(
                     min_arg_count, len(type_vars), len(args), ctx

mypy/checkmember.py

@@ -1519,6 +1519,7 @@ def bind_self_fast(method: F, original_type: Type | None = None) -> F:
         arg_kinds=method.arg_kinds[1:],
         arg_names=method.arg_names[1:],
         is_bound=True,
+        original_self_type=method.arg_types[0],
     )
 
 

mypy/exportjson.py

@@ -467,6 +467,9 @@ def convert_callable_type(self: CallableType) -> Json:
         "is_ellipsis_args": self.is_ellipsis_args,
         "implicit": self.implicit,
         "is_bound": self.is_bound,
+        "original_self_type": (
+            convert_type(self.original_self_type) if self.original_self_type is not None else None
+        ),
         "type_guard": convert_type(self.type_guard) if self.type_guard is not None else None,
         "type_is": convert_type(self.type_is) if self.type_is is not None else None,
         "from_concatenate": self.from_concatenate,

mypy/server/astdiff.py

@@ -471,6 +471,7 @@ def visit_callable_type(self, typ: CallableType) -> SnapshotItem:
             typ.is_ellipsis_args,
             snapshot_types(typ.variables),
             typ.is_bound,
+            snapshot_types([typ.original_self_type] if typ.original_self_type is not None else []),
         )
 
     def normalize_callable_variables(self, typ: CallableType) -> CallableType:

mypy/typeops.py

@@ -205,6 +205,7 @@ def type_object_type(info: TypeInfo, named_type: Callable[[str], Instance]) -> P
                     arg_names=["_args", "_kwds"],
                     ret_type=any_type,
                     is_bound=True,
+                    original_self_type=any_type,
                     fallback=named_type("builtins.function"),
                 )
                 result: FunctionLike = class_callable(sig, info, fallback, None, is_new=False)
@@ -490,6 +491,7 @@ class B(A): pass
         arg_names=func.arg_names[1:],
         variables=variables,
         is_bound=True,
+        original_self_type=func.arg_types[0],
     )
     return cast(F, res)
 

mypy/types.py

@@ -2169,6 +2169,7 @@ class CallableType(FunctionLike):
         "from_type_type",  # Was this callable generated by analyzing Type[...]
         # instantiation?
         "is_bound",  # Is this a bound method?
+        "original_self_type",  # If bound, what was the type of `self` before?
         "type_guard",  # T, if -> TypeGuard[T] (ret_type is bool in this case).
         "type_is",  # T, if -> TypeIs[T] (ret_type is bool in this case).
         "from_concatenate",  # whether this callable is from a concatenate object
@@ -2195,6 +2196,7 @@ def __init__(
         special_sig: str | None = None,
         from_type_type: bool = False,
         is_bound: bool = False,
+        original_self_type: Type | None = None,
         type_guard: Type | None = None,
         type_is: Type | None = None,
         from_concatenate: bool = False,
@@ -2232,6 +2234,7 @@ def __init__(
         self.from_concatenate = from_concatenate
         self.imprecise_arg_kinds = imprecise_arg_kinds
         self.is_bound = is_bound
+        self.original_self_type = original_self_type
         self.type_guard = type_guard
         self.type_is = type_is
         self.unpack_kwargs = unpack_kwargs
@@ -2253,6 +2256,7 @@ def copy_modified(
         special_sig: Bogus[str | None] = _dummy,
         from_type_type: Bogus[bool] = _dummy,
         is_bound: Bogus[bool] = _dummy,
+        original_self_type: Bogus[Type | None] = _dummy,
         type_guard: Bogus[Type | None] = _dummy,
         type_is: Bogus[Type | None] = _dummy,
         from_concatenate: Bogus[bool] = _dummy,
@@ -2277,6 +2281,9 @@ def copy_modified(
             special_sig=special_sig if special_sig is not _dummy else self.special_sig,
             from_type_type=from_type_type if from_type_type is not _dummy else self.from_type_type,
             is_bound=is_bound if is_bound is not _dummy else self.is_bound,
+            original_self_type=(
+                original_self_type if original_self_type is not _dummy else self.original_self_type
+            ),
             type_guard=type_guard if type_guard is not _dummy else self.type_guard,
             type_is=type_is if type_is is not _dummy else self.type_is,
             from_concatenate=(
@@ -2598,6 +2605,11 @@ def serialize(self) -> JsonDict:
             "is_ellipsis_args": self.is_ellipsis_args,
             "implicit": self.implicit,
             "is_bound": self.is_bound,
+            "original_self_type": (
+                self.original_self_type.serialize()
+                if self.original_self_type is not None
+                else None
+            ),
             "type_guard": self.type_guard.serialize() if self.type_guard is not None else None,
             "type_is": (self.type_is.serialize() if self.type_is is not None else None),
             "from_concatenate": self.from_concatenate,
@@ -2620,6 +2632,11 @@ def deserialize(cls, data: JsonDict) -> CallableType:
             is_ellipsis_args=data["is_ellipsis_args"],
             implicit=data["implicit"],
             is_bound=data["is_bound"],
+            original_self_type=(
+                deserialize_type(data["original_self_type"])
+                if data["original_self_type"] is not None
+                else None
+            ),
             type_guard=(
                 deserialize_type(data["type_guard"]) if data["type_guard"] is not None else None
             ),
@@ -2641,6 +2658,7 @@ def write(self, data: Buffer) -> None:
         write_bool(data, self.is_ellipsis_args)
         write_bool(data, self.implicit)
         write_bool(data, self.is_bound)
+        write_type_opt(data, self.original_self_type)
         write_type_opt(data, self.type_guard)
         write_type_opt(data, self.type_is)
         write_bool(data, self.from_concatenate)
@@ -2663,6 +2681,7 @@ def read(cls, data: Buffer) -> CallableType:
             is_ellipsis_args=read_bool(data),
             implicit=read_bool(data),
             is_bound=read_bool(data),
+            original_self_type=read_type_opt(data),
             type_guard=read_type_opt(data),
             type_is=read_type_opt(data),
             from_concatenate=read_bool(data),

test-data/unit/check-overloading.test

@@ -6852,3 +6852,20 @@ if isinstance(headers, dict):
 
 reveal_type(headers)  # N: Revealed type is "Union[__main__.Headers, typing.Iterable[tuple[builtins.bytes, builtins.bytes]]]"
 [builtins fixtures/isinstancelist.pyi]
+
+[case testSelfOverloadWithAnySelf]
+from typing import Any, Generic, TypeVar, overload
+
+T = TypeVar("T")
+
+class A(Generic[T]):
+    @overload
+    def run(self: A[int]) -> int: ...
+    @overload
+    def run(self: A[str]) -> str: ...
+    def run(self: "A[int] | A[str]") -> "int | str": ...
+
+foo: A[Any]
+reveal_type(foo.run())  # N: Revealed type is "Any"
+reveal_type(A.run(foo))  # N: Revealed type is "Any"
+[builtins fixtures/tuple.pyi]

test-data/unit/exportjson.test

@@ -170,6 +170,7 @@ def foo(a: int) -> None: ...
                     "is_ellipsis_args": false,
                     "implicit": false,
                     "is_bound": false,
+                    "original_self_type": null,
                     "type_guard": null,
                     "type_is": null,
                     "from_concatenate": false,