Prerequisites

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Steps to reproduce

If i define a list, an arraylist or an array in a function, when I attempt to return them, they all return as arrays. In the sample code below I set up a generic list of strings, an array list, and an array. No matter which one I return, the returned value is always an Array, not a list or an arraylist. This is, I hope, obviously suboptimal.

function badArrayReturn {
	#test to demonstrate issues with PowerShell returning collection types incorrectly
	$theList = [System.Collections.Generic.List[string]]::New()
	$theArray = @()
	$theArrayList = [System.Collections.ArrayList]::New()

	$theList.Add("item1")|Out-Null
	$theList.Add("item2")|Out-Null

	$theArray += "item3"
	$theArray += "item4"

	$theArrayList.Add("item5")
	$theArrayList.Add("item6")

	$theList.GetType()

	return $theList

}

$returnedList = badArrayReturn

$returnedList.GetType()

Expected behavior

When I return a generic list or an arraylist from a function, I expect the returned value to stay that way, not be coerced to a standard array.

Actual behavior

lists and arraylists are returned as arrays

Error details

Environment data

$PSVersionTable                     

Name                           Value
----                           -----
PSVersion                      7.6.0-preview.6
PSEdition                      Core
GitCommitId                    7.6.0-preview.6
OS                             macOS 26.3.0
Platform                       Unix
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.4
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Visuals

No response