Fix: Issue #2307

capa/features/freeze/features.py

@@ -6,7 +6,7 @@
 #  is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and limitations under the License.
 import binascii
-from typing import Union, Optional
+from typing import Union, Optional, Annotated
 
 from pydantic import Field, BaseModel, ConfigDict
 
@@ -348,29 +348,32 @@ class OperandOffsetFeature(FeatureModel):
     description: Optional[str] = None
 
 
-Feature = Union[
-    OSFeature,
-    ArchFeature,
-    FormatFeature,
-    MatchFeature,
-    CharacteristicFeature,
-    ExportFeature,
-    ImportFeature,
-    SectionFeature,
-    FunctionNameFeature,
-    SubstringFeature,
-    RegexFeature,
-    StringFeature,
-    ClassFeature,
-    NamespaceFeature,
-    APIFeature,
-    PropertyFeature,
-    NumberFeature,
-    BytesFeature,
-    OffsetFeature,
-    MnemonicFeature,
-    OperandNumberFeature,
-    OperandOffsetFeature,
-    # Note! this must be last, see #1161
-    BasicBlockFeature,
+Feature = Annotated[
+    Union[
+        OSFeature,
+        ArchFeature,
+        FormatFeature,
+        MatchFeature,
+        CharacteristicFeature,
+        ExportFeature,
+        ImportFeature,
+        SectionFeature,
+        FunctionNameFeature,
+        SubstringFeature,
+        RegexFeature,
+        StringFeature,
+        ClassFeature,
+        NamespaceFeature,
+        APIFeature,
+        PropertyFeature,
+        NumberFeature,
+        BytesFeature,
+        OffsetFeature,
+        MnemonicFeature,
+        OperandNumberFeature,
+        OperandOffsetFeature,
+        # Note! this must be last, see #1161
+        BasicBlockFeature,
+    ],
+    Field(discriminator="type"),
 ]