diff --git a/src/plugins/qmldesigner/designercore/projectstorage/projectstorage.h b/src/plugins/qmldesigner/designercore/projectstorage/projectstorage.h
index bf2f80790f1..540f10105f6 100644
--- a/src/plugins/qmldesigner/designercore/projectstorage/projectstorage.h
+++ b/src/plugins/qmldesigner/designercore/projectstorage/projectstorage.h
@@ -555,7 +555,7 @@ private:
             return Sqlite::CallbackControl::Continue;
         };
 
-        updatePrototypeToNullStatement.readCallback(callback, &prototypeId);
+        updatePrototypeIdToNullStatement.readCallback(callback, &prototypeId);
     }
 
     void deleteType(TypeId typeId,
@@ -640,6 +640,7 @@ private:
             }
 
             updateTypePrototypeStatement.write(&prototype.typeId, &prototypeId, &prototypeNameId);
+            checkForPrototypeChainCycle(prototype.typeId);
         }
     }
 
@@ -1093,6 +1094,18 @@ private:
         synchronizeEnumerationDeclarations(typeId, type.enumerationDeclarations);
     }
 
+    void checkForPrototypeChainCycle(TypeId typeId)
+    {
+        auto callback = [=](long long currentTypeId) {
+            if (typeId == TypeId{currentTypeId})
+                throw PrototypeChainCycle{};
+
+            return Sqlite::CallbackControl::Continue;
+        };
+
+        selectTypeIdsForPrototypeChainIdStatement.readCallback(callback, &typeId);
+    }
+
     void syncPrototypes(Storage::Type &type)
     {
         if (Utils::visit([](auto &&typeName) -> bool { return typeName.name.isEmpty(); },
@@ -1106,6 +1119,7 @@ private:
                 throw TypeNameDoesNotExists{};
 
             updatePrototypeStatement.write(&type.typeId, &prototypeId, &prototypeTypeNameId);
+            checkForPrototypeChainCycle(type.typeId);
         }
     }
 
@@ -1517,11 +1531,8 @@ public:
     Initializer initializer;
     ReadWriteStatement<1> upsertTypeStatement{
         "INSERT INTO types(importId, name,  accessSemantics, sourceId) VALUES(?1, ?2, "
-        "?3, nullif(?4, -1)) ON "
-        "CONFLICT DO UPDATE SET prototypeId=excluded.prototypeId, "
-        "accessSemantics=excluded.accessSemantics, sourceId=excluded.sourceId WHERE "
-        "prototypeId iS NOT excluded.prototypeId OR accessSemantics IS NOT "
-        "excluded.accessSemantics OR "
+        "?3, nullif(?4, -1)) ON CONFLICT DO UPDATE SET  accessSemantics=excluded.accessSemantics, "
+        "sourceId=excluded.sourceId WHERE accessSemantics IS NOT excluded.accessSemantics OR "
         "sourceId IS NOT excluded.sourceId RETURNING typeId",
         database};
     WriteStatement updatePrototypeStatement{
@@ -1819,13 +1830,21 @@ public:
     ReadStatement<1> selectPropertyDeclarationIdStatement{
         "SELECT propertyDeclarationId FROM propertyDeclarations WHERE propertyDeclarationId=?",
         database};
-    ReadWriteStatement<3> updatePrototypeToNullStatement{
+    ReadWriteStatement<3> updatePrototypeIdToNullStatement{
         "UPDATE types SET prototypeId=NULL WHERE prototypeId=?1 RETURNING "
         "typeId, prototypeNameId, sourceId",
         database};
     ReadStatement<1> selectTypeIdStatement{"SELECT typeId FROM types WHERE typeId=?", database};
     WriteStatement updateTypePrototypeStatement{
         "UPDATE types SET prototypeId=?2, prototypeNameId=?3 WHERE typeId=?1", database};
+    mutable ReadStatement<1> selectTypeIdsForPrototypeChainIdStatement{
+        "WITH RECURSIVE "
+        "  prototypes(typeId) AS ("
+        "       SELECT prototypeId FROM types WHERE typeId=? "
+        "    UNION ALL "
+        "      SELECT prototypeId FROM types JOIN prototypes USING(typeId)) "
+        "SELECT typeId FROM prototypes",
+        database};
 };
 
 } // namespace QmlDesigner
diff --git a/src/plugins/qmldesigner/designercore/projectstorage/projectstorageexceptions.h b/src/plugins/qmldesigner/designercore/projectstorage/projectstorageexceptions.h
index aedfcca712f..567d1989976 100644
--- a/src/plugins/qmldesigner/designercore/projectstorage/projectstorageexceptions.h
+++ b/src/plugins/qmldesigner/designercore/projectstorage/projectstorageexceptions.h
@@ -89,4 +89,10 @@ public:
     const char *what() const noexcept override { return "The property name does not exist!"; }
 };
 
+class PrototypeChainCycle : std::exception
+{
+public:
+    const char *what() const noexcept override { return "There is a prototype chain cycle!"; }
+};
+
 } // namespace QmlDesigner
diff --git a/tests/unit/unittest/projectstorage-test.cpp b/tests/unit/unittest/projectstorage-test.cpp
index ddb3e2e2532..0caf8bc5433 100644
--- a/tests/unit/unittest/projectstorage-test.cpp
+++ b/tests/unit/unittest/projectstorage-test.cpp
@@ -912,8 +912,15 @@ TEST_F(ProjectStorageSlowTest, SynchronizeTypesAddsNewTypesThrowsWithWrongExport
 TEST_F(ProjectStorageSlowTest, SynchronizeTypesAddsNewTypesWithMissingImportAndExportedPrototypeName)
 {
     Storage::Types types{createTypes()};
+    types.push_back(Storage::Type{importId3,
+                                  "QObject2",
+                                  Storage::NativeType{},
+                                  TypeAccessSemantics::Reference,
+                                  sourceId4,
+                                  importIds,
+                                  {Storage::ExportedType{"Object2"}, Storage::ExportedType{"Obj2"}}});
     storage.synchronizeDocuments({Storage::Document{sourceId1, {importId1}}});
-    types[1].prototype = Storage::ExportedType{"Object"};
+    types[1].prototype = Storage::ExportedType{"Object2"};
 
     ASSERT_THROW(storage.synchronizeTypes(types, {sourceId1, sourceId2}),
                  QmlDesigner::TypeNameDoesNotExists);
@@ -3070,4 +3077,40 @@ TEST_F(ProjectStorageSlowTest, ChangePrototypeTypeNameThrowsForWrongNativeProtot
                  QmlDesigner::TypeNameDoesNotExists);
 }
 
+TEST_F(ProjectStorageSlowTest, ThrowForPrototypeChainCycles)
+{
+    Storage::Types types{createTypes()};
+    types[1].prototype = Storage::ExportedType{"Object2"};
+    types.push_back(Storage::Type{importId3,
+                                  "QObject2",
+                                  Storage::ExportedType{"Item"},
+                                  TypeAccessSemantics::Reference,
+                                  sourceId3,
+                                  importIds,
+                                  {Storage::ExportedType{"Object2"}, Storage::ExportedType{"Obj2"}}});
+
+    ASSERT_THROW(storage.synchronizeTypes(types, {sourceId1, sourceId2, sourceId3}),
+                 QmlDesigner::PrototypeChainCycle);
+}
+
+TEST_F(ProjectStorageSlowTest, ThrowForTypeIdAndPrototypeIdAreTheSame)
+{
+    Storage::Types types{createTypes()};
+    types[1].prototype = Storage::ExportedType{"Object"};
+
+    ASSERT_THROW(storage.synchronizeTypes(types, {sourceId1, sourceId2}),
+                 QmlDesigner::PrototypeChainCycle);
+}
+
+TEST_F(ProjectStorageSlowTest, ThrowForTypeIdAndPrototypeIdAreTheSameForRelinking)
+{
+    Storage::Types types{createTypes()};
+    types[0].propertyDeclarations[0].typeName = Storage::ExportedType{"Object"};
+    types[0].prototype = Storage::ExportedType{"Object"};
+    storage.synchronizeTypes(types, {sourceId1, sourceId2});
+    types[1].prototype = Storage::ExportedType{"Item"};
+    types[1].typeName = "QObject2";
+
+    ASSERT_THROW(storage.synchronizeTypes({types[1]}, {sourceId2}), QmlDesigner::PrototypeChainCycle);
+}
 } // namespace