diff --git a/construct_typed/dataclass_struct.py b/construct_typed/dataclass_struct.py
index 78d2e59..d72ce5c 100644
--- a/construct_typed/dataclass_struct.py
+++ b/construct_typed/dataclass_struct.py
@@ -27,6 +27,8 @@ class DataclassMixin:
     methods exists and every name can be used.
     """
 
+    __dataclass_fields__: t.ClassVar[dict[str, dataclasses.Field[t.Any]]]
+
     def __getitem__(self, key: str) -> t.Any:
         return getattr(self, key)
 
@@ -269,4 +271,4 @@ TBitStruct = DataclassBitStruct
 TContainerMixin = DataclassMixin
 TContainerBase = DataclassMixin
 TStructField = csfield
-sfield = csfield
\ No newline at end of file
+sfield = csfield
diff --git a/tests/test_typed.py b/tests/test_typed.py
index 4dd9528..7d726a3 100644
--- a/tests/test_typed.py
+++ b/tests/test_typed.py
@@ -384,7 +384,7 @@ def test_tenum_no_enumbase() -> None:
     assert raises(lambda: cst.TEnum(cs.Byte, cls)) == TypeError
 
 
-def test_tenum_asdict():
+def test_tenum_asdict() -> None:
     # see: https://github.com/timrid/construct-typing/issues/21
     import construct_typed as cst
     import dataclasses
@@ -498,7 +498,7 @@ def test_tenum_flags() -> None:
     assert raises(d.build, 2) == TypeError
 
 
-def test_tenum_flags_asdict():
+def test_tenum_flags_asdict() -> None:
     import construct_typed as cst
     import dataclasses