server and incremental

mypy/fixup.py

@@ -239,6 +239,9 @@ def visit_instance(self, inst: Instance) -> None:
             a.accept(self)
         if inst.last_known_value is not None:
             inst.last_known_value.accept(self)
+        if inst.extra_attrs:
+            for v in inst.extra_attrs.attrs.values():
+                v.accept(self)
 
     def visit_type_alias_type(self, t: TypeAliasType) -> None:
         type_ref = t.type_ref

mypy/server/astdiff.py

@@ -378,11 +378,19 @@ def visit_deleted_type(self, typ: DeletedType) -> SnapshotItem:
         return snapshot_simple_type(typ)
 
     def visit_instance(self, typ: Instance) -> SnapshotItem:
+        if self.extra_attrs:
+            extra_attrs = (
+                tuple(sorted((k, self.visit(v)) for k, v in self.extra_attrs.attrs.items())),
+                tuple(self.extra_attrs.immutable),
+            )
+        else:
+            extra_attrs = ()
         return (
             "Instance",
             encode_optional_str(typ.type.fullname),
             snapshot_types(typ.args),
             ("None",) if typ.last_known_value is None else snapshot_type(typ.last_known_value),
+            extra_attrs,
         )
 
     def visit_type_var(self, typ: TypeVarType) -> SnapshotItem:

mypy/types.py

@@ -1356,6 +1356,23 @@ def copy(self) -> ExtraAttrs:
     def __repr__(self) -> str:
         return f"ExtraAttrs({self.attrs!r}, {self.immutable!r}, {self.mod_name!r})"
 
+    def serialize(self) -> JsonDict:
+        return {
+            ".class": "ExtraAttrs",
+            "attrs": {k: v.serialize() for k, v in self.attrs.items()},
+            "immutable": list(self.immutable),
+            "mod_name": self.mod_name,
+        }
+
+    @classmethod
+    def deserialize(cls, data: JsonDict) -> ExtraAttrs:
+        assert data[".class"] == "ExtraAttrs"
+        return ExtraAttrs(
+            {k: deserialize_type(v) for k, v in data["attrs"].items()},
+            set(data["immutable"]),
+            data["mod_name"],
+        )
+
 
 class Instance(ProperType):
     """An instance type of form C[T1, ..., Tn].
@@ -1468,6 +1485,7 @@ def serialize(self) -> JsonDict | str:
         data["args"] = [arg.serialize() for arg in self.args]
         if self.last_known_value is not None:
             data["last_known_value"] = self.last_known_value.serialize()
+        data["extra_attrs"] = self.extra_attrs.serialize() if self.extra_attrs else None
         return data
 
     @classmethod
@@ -1486,6 +1504,8 @@ def deserialize(cls, data: JsonDict | str) -> Instance:
         inst.type_ref = data["type_ref"]  # Will be fixed up by fixup.py later.
         if "last_known_value" in data:
             inst.last_known_value = LiteralType.deserialize(data["last_known_value"])
+        if data.get("extra_attrs") is not None:
+            inst.extra_attrs = ExtraAttrs.deserialize(data["extra_attrs"])
         return inst
 
     def copy_modified(

test-data/unit/check-incremental.test

@@ -6574,3 +6574,63 @@ class TheClass:
 [out]
 [out2]
 tmp/a.py:3: note: Revealed type is "def (value: builtins.object) -> lib.TheClass.pyenum@6"
+
+
+[case testIncrementalFunctoolsPartial]
+import a
+
+[file a.py]
+from typing import Callable
+from partial import p1, p2
+
+p1(1, "a", 3)  # OK
+p1(1, "a", c=3)  # OK
+p1(1, b="a", c=3)  # OK
+
+reveal_type(p1)
+
+def takes_callable_int(f: Callable[..., int]) -> None: ...
+def takes_callable_str(f: Callable[..., str]) -> None: ...
+takes_callable_int(p1)
+takes_callable_str(p1)
+
+p2("a")  # OK
+p2("a", 3)  # OK
+p2("a", c=3)  # OK
+p2(1, 3)
+p2(1, "a", 3)
+p2(a=1, b="a", c=3)
+
+[file a.py.2]
+from typing import Callable
+from partial import p3
+
+p3(1)  # OK
+p3(1, c=3)  # OK
+p3(a=1)  # OK
+p3(1, b="a", c=3)  # OK, keywords can be clobbered
+p3(1, 3)
+
+[file partial.py]
+from typing import Callable
+import functools
+
+def foo(a: int, b: str, c: int = 5) -> int: ...
+
+p1 = functools.partial(foo)
+p2 = functools.partial(foo, 1)
+p3 = functools.partial(foo, b="a")
+[builtins fixtures/dict.pyi]
+[out]
+tmp/a.py:8: note: Revealed type is "functools.partial[builtins.int]"
+tmp/a.py:13: error: Argument 1 to "takes_callable_str" has incompatible type "partial[int]"; expected "Callable[..., str]"
+tmp/a.py:13: note: "partial[int].__call__" has type "Callable[[VarArg(Any), KwArg(Any)], int]"
+tmp/a.py:18: error: Argument 1 to "foo" has incompatible type "int"; expected "str"
+tmp/a.py:19: error: Too many arguments for "foo"
+tmp/a.py:19: error: Argument 1 to "foo" has incompatible type "int"; expected "str"
+tmp/a.py:19: error: Argument 2 to "foo" has incompatible type "str"; expected "int"
+tmp/a.py:20: error: Unexpected keyword argument "a" for "foo"
+tmp/partial.py:4: note: "foo" defined here
+[out2]
+tmp/a.py:8: error: Too many positional arguments for "foo"
+tmp/a.py:8: error: Argument 2 to "foo" has incompatible type "int"; expected "str"