Regression in v1.5.1: TypeError: Invalid value used as weak map key

[ddolcimascolo]

Describe the bug

Lots of my tests now fail with

TypeError: Invalid value used as weak map key
    at WeakMap.set (<anonymous>)
    at file:///data/dev/cmdb/frontend/node_modules/@vitest/expect/dist/index.js:389:24
    at Array.every (<anonymous>)
    at file:///data/dev/cmdb/frontend/node_modules/@vitest/expect/dist/index.js:384:33
    at Object.subsetEquality (file:///data/dev/cmdb/frontend/node_modules/@vitest/expect/dist/index.js:399:37)
    at eq (file:///data/dev/cmdb/frontend/node_modules/@vitest/expect/dist/index.js:166:49)
    at equals (file:///data/dev/cmdb/frontend/node_modules/@vitest/expect/dist/index.js:129:10)
    at Proxy.<anonymous> (file:///data/dev/cmdb/frontend/node_modules/@vitest/expect/dist/index.js:931:18)
    at Proxy.<anonymous> (file:///data/dev/cmdb/frontend/node_modules/@vitest/expect/dist/index.js:797:17)
    at Proxy.methodWrapper (/data/dev/cmdb/frontend/node_modules/chai/lib/chai/utils/addMethod.js:57:25)

Reproduction

Not entirely sure, but I suspect a toMatchObject with an object with null keys. Like in expect(x).toMatchObject({ aNullKey: null })

System Info

System:
    OS: Linux 6.5 Linux Mint 21.3 (Virginia)
    CPU: (16) x64 11th Gen Intel(R) Core(TM) i7-11850H @ 2.50GHz
    Memory: 2.26 GB / 15.34 GB
    Container: Yes
    Shell: 5.1.16 - /bin/bash
  Binaries:
    Node: 20.9.0 - ~/.nvm/versions/node/v20.9.0/bin/node
    Yarn: 1.22.19 - ~/.nvm/versions/node/v20.9.0/bin/yarn
    npm: 10.1.0 - ~/.nvm/versions/node/v20.9.0/bin/npm
    pnpm: 8.12.1 - ~/.nvm/versions/node/v20.9.0/bin/pnpm
  Browsers:
    Chrome: 124.0.6367.60

Used Package Manager

npm

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[ruicsh]

yes, reproducible with objects with null values:

expect(actual).toMatchObject({ foo: null })

it works with 1.5.0, breaks with 1.5.1

[sheremet-va]

Fixed in ce36845

[ddolcimascolo]

Thx for fixing @sheremet-va. Will you release a new version soon, or deprecate v1.5.1? The problem seems quite severe to me...