format-default: No coercion operator is defined

Steps to reproduce

using namespace System.Collections.Generic

[LinkedList[Hashtable]]::new().AddLast( @{
    k1 = "v1"
})

Expected behavior

When this is executed in Windows Powershell, the hashtable is added to the linked list, and the link list is sent to the output stream.

List                           Next Previous Value
----                           ---- -------- -----
{System.Collections.Hashtable}               {k1} 

Actual behavior

format-default: No coercion operator is defined between types 'System.Collections.Hashtable&' and 'System.Object'.

Environment data

Name                           Value
----                           -----
PSVersion                      7.1.1
PSEdition                      Core
GitCommitId                    7.1.1
OS                             Microsoft Windows 10.0.19041
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

[SeeminglyScience]

I would caution against treating this like an edge case. It is currently, but this pattern is likely to pop up with increasing frequency.

Ideally PowerShell would know how to handle these properties as if they were any other indexer with both a getter and a setter. The setter will be a lot more challenging since iirc SLE.Expression will throw with a method invocation on the LHS of Assign but for get it should be able to just dereference.

(Note: if set is implemented, care should be taken to not allow setting to ref readonly returns)

[msftbot[bot]]

🎉This issue was addressed in #16956, which has now been successfully released as v7.3.0-preview.3.🎉

Handy links:

• Release Notes