feat: inheritance should work with computed (#3950)

* inheritance should work with computed

* fix

* improve

Author: jzhan-canva

packages/mobx/__tests__/decorators_20223/stage3-decorators.ts

@@ -1115,3 +1115,22 @@ test(`decorated field can be inherited, but doesn't inherite the effect of decor
     const subStore = new SubStore()
     expect(isAction(subStore.action)).toBe(false)
 })
+
+test(`inheritance should work with computed`, () => {
+    class Store {
+        @computed
+        get getNumber() {
+            return 1
+        }
+    }
+
+    class SubStore extends Store {
+        @computed
+        override get getNumber() {
+            return super.getNumber + 1
+        }
+    }
+
+    const store = new SubStore()
+    expect(store.getNumber).toBe(2)
+})

packages/mobx/src/types/computedannotation.ts

@@ -64,11 +64,13 @@ function decorate_20223_(this: Annotation, get, context: ClassGetterDecoratorCon
         options.name ||= __DEV__
             ? `${adm.name_}.${key.toString()}`
             : `ObservableObject.${key.toString()}`
-        adm.values_.set(key, new ComputedValue(options))
+        const computedValue = new ComputedValue(options)
+        adm.values_.set(key, computedValue)
+        adm.values_.set(get, computedValue)
     })
 
     return function () {
-        return this[$mobx].getObservablePropValue_(key)
+        return this[$mobx].getObservablePropValue_(get)
     }
 }