Allow iterable class objects to be unpacked

mypy/checker.py

@@ -3399,6 +3399,14 @@ def check_multi_assignment(
             if len(relevant_items) == 1:
                 rvalue_type = get_proper_type(relevant_items[0])
 
+        if isinstance(rvalue_type, FunctionLike) and rvalue_type.is_type_obj():
+            ret_type = get_proper_type(rvalue_type.items[0].ret_type)
+            if isinstance(ret_type, Instance):
+                rvalue_type = ret_type.type.metaclass_type or rvalue_type
+
+        if isinstance(rvalue_type, TypeType) and isinstance(rvalue_type.item, Instance):
+            rvalue_type = rvalue_type.item.type.metaclass_type or rvalue_type
+
         if isinstance(rvalue_type, AnyType):
             for lv in lvalues:
                 if isinstance(lv, StarExpr):

test-data/unit/check-inference.test

@@ -270,6 +270,22 @@ def f() -> None:
 class A: pass
 [out]
 
+[case testInferringLvarTypesUnpackedFromIterableClassObject]
+from typing import Iterator, Type
+class Meta(type):
+    def __iter__(cls) -> Iterator[int]:
+        yield from [1, 2, 3]
+
+class Foo(metaclass=Meta): ...
+
+a, b, c = Foo
+reveal_type(a)  # N: Revealed type is "builtins.int"
+
+F: Type[Foo] = Foo
+d, e, f = F
+reveal_type(d)  # N: Revealed type is "builtins.int"
+[out]
+
 [case testInferringLvarTypesInMultiDefWithInvalidTuple]
 from typing import Tuple
 t = None # type: Tuple[object, object, object]