fix(reactivity): differentiate shallow/deep proxies of same target when nested in reactive

fix #5271

packages/reactivity/src/baseHandlers.ts

@@ -8,7 +8,8 @@ import {
   reactiveMap,
   shallowReactiveMap,
   shallowReadonlyMap,
-  isReadonly
+  isReadonly,
+  isShallow
 } from './reactive'
 import { TrackOpTypes, TriggerOpTypes } from './operations'
 import {
@@ -150,8 +151,10 @@ function createSetter(shallow = false) {
   ): boolean {
     let oldValue = (target as any)[key]
     if (!shallow && !isReadonly(value)) {
-      value = toRaw(value)
-      oldValue = toRaw(oldValue)
+      if (!isShallow(value)) {
+        value = toRaw(value)
+        oldValue = toRaw(oldValue)
+      }
       if (!isArray(target) && isRef(oldValue) && !isRef(value)) {
         oldValue.value = value
         return true