Asymmetric matcher objectContaining mutates arguments

[kylebjordahl]

🐛 Bug Report

When using a local variable as an argument to an objectContaining asymmetric matcher, the variable is mutated in the containing scope.

To Reproduce

Steps to reproduce the behavior: see example repl.it

Expected behavior

Asymmetric matchers should not mutate their input arguments.

Link to repl or repo (highly encouraged)

https://repl.it/repls/CylindricalTenderDemand#objectContaining-mutates.test.js

envinfo

System:
    OS: macOS 10.15.6
    CPU: (16) x64 Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz
  Binaries:
    Node: 12.16.1 - ~/.nvm/versions/node/v12.16.1/bin/node
    Yarn: 1.22.5 - /usr/local/bin/yarn
    npm: 6.13.4 - ~/.nvm/versions/node/v12.16.1/bin/npm
  npmPackages:
    jest: ^26.6.1 => 26.6.1 

[kylebjordahl]

Just noticed that #10508 is on the release notes for 26.6.1, I'd hazard a guess it's related to that...

EDIT: and just noticed #10689. Closing in favor of that

[github-actions]

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