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diff --git a/packages/main/src/utils/overrideProps.ts b/packages/main/src/utils/overrideProps.ts
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+/*
+ * Copyright (C)  2022 Kristóf Marussy <kristof@marussy.com>
+ *
+ * This file is part of Sophie.
+ *
+ * Sophie is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+/**
+ * @file This file implements a technique to force-override properties of a model.
+ *
+ * The overridden properties must conform to the SnapshotIt and SnapshotOut format
+ * of the original model. Essentially, this means that only views and actions can
+ * be added safely.
+ *
+ * @see https://github.com/mobxjs/mobx-state-tree/issues/1403#issuecomment-940843087
+ */
+
+import {
+  IAnyModelType,
+  IModelType,
+  ModelProperties,
+  SnapshotIn,
+  SnapshotOut,
+} from 'mobx-state-tree';
+
+export type IUnsafeOverriddenModelType<
+  BASE extends IAnyModelType,
+  PROPS extends ModelProperties,
+> = BASE extends IModelType<infer P, infer O, infer CC, infer CS>
+  ? IModelType<Omit<P, keyof PROPS> & PROPS, O, CC, CS>
+  : never;
+
+export type IOverriddenModelType<
+  BASE extends IAnyModelType,
+  PROPS extends ModelProperties,
+> = SnapshotIn<BASE> extends SnapshotIn<IUnsafeOverriddenModelType<BASE, PROPS>>
+  ? SnapshotOut<
+      IUnsafeOverriddenModelType<BASE, PROPS>
+    > extends SnapshotOut<BASE>
+    ? IUnsafeOverriddenModelType<BASE, PROPS>
+    : never
+  : never;
+
+export default function overrideProps<
+  BASE extends IAnyModelType,
+  PROPS extends ModelProperties,
+>(base: BASE, props: PROPS): IOverriddenModelType<BASE, PROPS> {
+  return base.props(props) as IOverriddenModelType<BASE, PROPS>;
+}