.GetHashCode() should not report the same value for all instances of [pscustomobject]

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Steps to reproduce

[pscustomobject] is a reference type without overridden equality-comparison behavior, so testing for equality performs reference equality, i.e. the test only succeeds if to values point to the very same instance.

Such types usually use the default (inherited) .GetHashCode() implementation, which for reference types means a value that is derived from the instance's identity.

Unexpectedly, all [pscustomobject] instances return the same from their .GetHashCode() method, which makes [pscustomobject] unsuitable as a hashtable key, for instance.

Expected behavior

PS> ([pscustomobject] @{ foo=1 }).GetHashCode() -eq ([pscustomobject] @{ foo=1 }).GetHashCode()
False # Two distinct [pscustomobject] instances that compare unequally should have distinct hash codes.

Actual behavior

The above returns $true, even though [pscustomobject] @{ foo=1 } -eq [pscustomobject] @{ foo=1 } returns $false (due to reference equality being tested).

Error details

No response

Environment data

PowerShell Core 7.2.0-preview.7

Visuals

No response