diff --git a/mypy/nodes.py b/mypy/nodes.py
index f25d3abab7bc..5a27783e97e1 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -2907,6 +2907,8 @@ def serialize(self) -> JsonDict:
                     None if self.typeddict_type is None else self.typeddict_type.serialize(),
                 'flags': get_flags(self, TypeInfo.FLAGS),
                 'metadata': self.metadata,
+                'slots': list(sorted(self.slots)) if self.slots is not None else None,
+                'deletable_attributes': self.deletable_attributes,
                 }
         return data
 
@@ -2944,6 +2946,8 @@ def deserialize(cls, data: JsonDict) -> 'TypeInfo':
         ti.typeddict_type = (None if data['typeddict_type'] is None
                             else mypy.types.TypedDictType.deserialize(data['typeddict_type']))
         ti.metadata = data['metadata']
+        ti.slots = set(data['slots']) if data['slots'] is not None else None
+        ti.deletable_attributes = data['deletable_attributes']
         set_flags(ti, data['flags'])
         return ti
 
diff --git a/mypyc/ir/class_ir.py b/mypyc/ir/class_ir.py
index ade04f39edcb..d6407610e2bc 100644
--- a/mypyc/ir/class_ir.py
+++ b/mypyc/ir/class_ir.py
@@ -325,6 +325,7 @@ def serialize(self) -> JsonDict:
             'children': [
                 cir.fullname for cir in self.children
             ] if self.children is not None else None,
+            'deletable': self.deletable,
         }
 
     @classmethod
@@ -373,6 +374,7 @@ def deserialize(cls, data: JsonDict, ctx: 'DeserMaps') -> 'ClassIR':
         ir.mro = [ctx.classes[s] for s in data['mro']]
         ir.base_mro = [ctx.classes[s] for s in data['base_mro']]
         ir.children = data['children'] and [ctx.classes[s] for s in data['children']]
+        ir.deletable = data['deletable']
 
         return ir
 
diff --git a/mypyc/test-data/fixtures/ir.py b/mypyc/test-data/fixtures/ir.py
index a661067845ac..a6914ccc36e5 100644
--- a/mypyc/test-data/fixtures/ir.py
+++ b/mypyc/test-data/fixtures/ir.py
@@ -294,7 +294,7 @@ def next(i: Iterator[T]) -> T: pass
 def next(i: Iterator[T], default: T) -> T: pass
 def hash(o: object) -> int: ...
 def globals() -> Dict[str, Any]: ...
-def getattr(obj: object, name: str) -> Any: ...
+def getattr(obj: object, name: str, default: Any = None) -> Any: ...
 def setattr(obj: object, name: str, value: Any) -> None: ...
 def enumerate(x: Iterable[T]) -> Iterator[Tuple[int, T]]: ...
 @overload
diff --git a/mypyc/test-data/run-multimodule.test b/mypyc/test-data/run-multimodule.test
index 20c9002cdf1d..6ffa166c57a1 100644
--- a/mypyc/test-data/run-multimodule.test
+++ b/mypyc/test-data/run-multimodule.test
@@ -798,3 +798,25 @@ def foo() -> int: return 10
 import native
 
 [rechecked native, other_a]
+
+[case testIncrementalCompilationWithDeletable]
+import other_a
+[file other_a.py]
+from other_b import C
+[file other_a.py.2]
+from other_b import C
+c = C()
+print(getattr(c, 'x', None))
+del c.x
+print(getattr(c, 'x', None))
+[file other_b.py]
+class C:
+    __deletable__ = ['x']
+    def __init__(self) -> None:
+        self.x = 0
+[file driver.py]
+import native
+[out]
+[out2]
+0
+None
diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test
index c990f52e74c8..caba9b73e594 100644
--- a/test-data/unit/check-incremental.test
+++ b/test-data/unit/check-incremental.test
@@ -5633,3 +5633,28 @@ main:5: error: Cannot override final attribute "x" (previously declared in base
 main:3: error: Cannot override writable attribute "x" with a final one
 main:4: error: Cannot extend enum with existing members: "FinalEnum"
 main:5: error: Cannot override final attribute "x" (previously declared in base class "FinalEnum")
+
+[case testSlotsSerialization]
+import a
+[file a.py]
+from b import C
+
+class D(C):
+    pass
+[file b.py]
+class C:
+    __slots__ = ('x',)
+[file a.py.2]
+from b import C
+
+class D(C):
+    __slots__ = ('y',)
+
+    def __init__(self) -> None:
+        self.x = 1
+        self.y = 2
+        self.z = 3
+[builtins fixtures/tuple.pyi]
+[out]
+[out2]
+tmp/a.py:9: error: Trying to assign name "z" that is not in "__slots__" of type "a.D"