Cannot Suppress Messages About a Specific Automatic Variable

[marshallwp]

Setting the CheckID of a SuppressMessageAttribute decoration to '_' fails to suppress the specified message about the '_' automatic variable.

Specifically, this fails:
[Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSAvoidAssignmentToAutomaticVariable', '_', Justification='Assignment is by design.')]
While this works as expected:
[Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSAvoidAssignmentToAutomaticVariable', '', Justification='Assignment is by design.')]

Steps to reproduce

Run Invoke-ScriptAnalyzer against the following PowerShell script.

function Import-StringData {
[Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSAvoidAssignmentToAutomaticVariable', '_', Justification='Assignment is by design.')]
[Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseDeclaredVarsMoreThanAssignments', 'newEntryTemplate', Justification='The subsequent use of newEntryTemplate is not detected by PSScriptAnalyzer.')]
Param([string]$stringToParse)
#region Prepare CrossRef Table
    [System.Data.DataTable]$dt = New-Object System.Data.DataTable
    $dt.Columns.Add("measCode", [string]) | Out-Null
    $dt.Columns.Add("measBasis", [string]) | Out-Null
    $dt.Rows.Add(@("BZ","MMBtu")) | Out-Null
    $dt.Rows.Add(@("G8","Gigacalories")) | Out-Null
    $dt.Rows.Add(@("GV","Gigajoules")) | Out-Null
    $dt.Rows.Add(@("TZ","MCF")) | Out-Null
    $dt.AcceptChanges()
#endregion Prepare CrossRef Table

    $stringToParse | Select-Object -First 7 | ForEach-Object -Begin {$newEntryTemplate = "`r`n{0}={1}"} -Process {
        $match = ($_ | Select-String "Meas Basis Desc[:] (.*)" -List).Matches
        if($null -ne $match){$_ += $newEntryTemplate -f "measCode", $dt.Select("measBasis='$($match.Groups[1].Value)'").measCode}
        $_ -replace ": ", "="} | ConvertFrom-StringData
}

$stringToParse = @"
Posting Date: 2020-09-17
Posting Time: 22:05:44    
Effective Gas Day: 2020-09-18
Effective Gas Time: 9:00:00 am  
Meas Basis Desc: MMBtu
"@

Import-StringData $stringToParse

Expected behavior

Invoke-ScriptAnalyzer should find 0 rule violations.

The PSAvoidAssignmentToAutomaticVariable warning about the '_' variable on line 18 should be suppressed as per the targeted SuppressMessageAttribute decoration on line 2.

Actual behavior

The SuppressMessageAttribute decoration on line 2 has no effect and Invoke-ScriptAnalyzer outputs the following:

Invoke-ScriptAnalyzer: Suppression Message Attribute error at line 2 in Test PSScriptAnalyzer.ps1 : Cannot find any DiagnosticRecord with the Rule Suppression ID _.

RuleName	Severity	ScriptName	Line	Message
PSAvoidAssignmentToAutomaticVariable	Warning	Test Suppression.ps1	18	The Variable '_' is an automatic variable that is built into PowerShell, assigning to it might have undesired side effects. If assignment is not by design, please use a different name.

1 rule violation found. Severity distribution: Error = 0, Warning = 1, Information = 0

Environment data

> $PSVersionTable
Name                           Value
----                           -----
PSVersion                      7.0.3
PSEdition                      Core
GitCommitId                    7.0.3
OS                             Microsoft Windows 10.0.18363
Platform                       Win32NT
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() }
1.19.1

[SydneyhSmith]

Thanks @BinaryWizard904 for the detailed information...what you are expecting is not something we support today--nothing ever diagnostic constructor for this rule does not take a Rule Suppression ID (suppression ID is on a rule by rule basis) so I will go ahead and mark this as a feature request...thanks!