Unused variable false positive in `ForEach-Object` begin block (`PSUseDeclaredVarsMoreThanAssignments`)

Prerequisites

• I have written a descriptive issue title.
• I have searched all open and closed issues to ensure it has not already been reported.
• I have read the troubleshooting guide.
• I am sure this issue is with the extension itself and does not reproduce in a standalone PowerShell instance.
• I have verified that I am using the latest version of Visual Studio Code and the PowerShell extension.
• If this is a security issue, I have read the security issue reporting guidance.

Summary

Variables initialized in begin block of ForEach-Object trigger PSUseDeclaredVarsMoreThanAssignments warning.

PowerShell Version

Name                           Value
----                           -----
PSVersion                      5.1.26100.7705
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.26100.7705
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Name             : ConsoleHost
Version          : 5.1.26100.7705
InstanceId       : 4ed60023-e437-45ae-b589-226f399acc62
UI               : System.Management.Automation.Internal.Host.InternalHostUserInterface
CurrentCulture   : en-US
CurrentUICulture : en-US
PrivateData      : Microsoft.PowerShell.ConsoleHost+ConsoleColorProxy
DebuggerEnabled  : True
IsRunspacePushed : False
Runspace         : System.Management.Automation.Runspaces.LocalRunspace

Visual Studio Code Version

1.109.5
072586267e68ece9a47aa43f8c108e0dcbf44622
x64

Extension Version

ms-vscode.powershell@2025.4.0

Steps to Reproduce

1, 2, 3 | ForEach-Object { $list = @() } { $list += $_ } { $list }

                           ^^^^^
The variable 'list' is assigned but never used.
PSScriptAnalyzer(PSUseDeclaredVarsMoreThanAssignments)

Returning the $list from the begin block offs the warning

1, 2, 3 | ForEach-Object { $list = @(); $list } { $list += $_ } { $list }

Visuals

No response

Logs

No response

Start by reproducing the diagnostic with the provided ForEach-Object example in the PowerShell extension and inspect how PSUseDeclaredVarsMoreThanAssignments results are handled. Compare the warning with the begin, process, and end blocks shown in the report. Done means the false positive is no longer reported while genuine unused-variable warnings still appear.