unary not is fooling tracker of variable use when assignment is in foreach loop

Steps to reproduce

Get-AzAutomationSchedule $resourceGroup $automationAccount | ForEach-Object {
            $PrimaryExists = $true
}

if (-not $PrimaryExists) {
    Write-Output "hello"
}

Expected behavior

$PrimaryExists should not be flagged as assigned but never used.

Actual behavior

It is flagged.

Environment data

> $PSVersionTable
Name                           Value
----                           -----
PSVersion                      6.2.3
PSEdition                      Core
GitCommitId                    6.2.3
OS                             Linux 4.15.0-1056-oem #65-Ubuntu SMP Thu Sep 12…
Platform                       Unix
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

> (Get-Module -ListAvailable PSScriptAnalyzer).Version | ForEach-Object { $_.ToString() }
1.18.3

Notes

I tried to create a more concise example, but the assignment needs to be a foreach { } at the end of a pipeline to exhibit the error.

首先运行提供的 PowerShell 管道，并检查末尾 ForEach-Object 块中赋值对应的分析器诊断。跟踪产生 assigned-but-unused 警告的变量使用分析，然后为此示例添加回归测试，并确认不再报告该警告，同时普通的未使用赋值仍会被标记。