Reassigning to the same Date object generates new copy with empty patches

🐛 Bug Report

If you mutate Date property inside produce but then revert it, immer still assumes changes while returning an empty set of patches.

Link to repro

https://codesandbox.io/s/immer-reassigning-breaks-immutabillity-2u7ob

import {enablePatches, produceWithPatches} from "immer"

enablePatches();

type DataObject = { 
  date: Date;
}

let initialDate = new Date();
let data: DataObject[] = [{date: initialDate}];

let [newData, patches] = produceWithPatches(data, draft => {
  let element = draft[0];
  let dateBefore = element.date;
 
  element.date = new Date()
  element.date = dateBefore;
});

console.log("Patches:", patches) // []
console.log("New Date equal to Initial", newData[0].date === initialDate) // true
console.log("Array equal", newData === data); // expect true but getting false

Environment

Immer version: 9.0.6

• I filed this report against the latest version of Immer
• Occurs with setUseProxies(true)
• Occurs with setUseProxies(false) (ES5 only)

Start with the linked CodeSandbox reproduction and the produceWithPatches entry point, checking the behavior under both Proxy and ES5 modes described in the report. The fix is complete when reverting a Date assignment returns the original array identity while still producing an empty patch set in both environments.