False Positive: Variable Reference Error for Colon After Variable in Double-Quoted Strings (Format Operator and Concatenation)

[twcau]

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Before submitting a bug report:

• I have reproduced this on the latest released version of PSScriptAnalyzer and VS Code PowerShell extension.
• I have searched for existing issues and did not find this bug reported.

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Steps to reproduce

$errorMsg = 'Some error details'
$feature = 'EnablePlacesWebApp'

# Using format operator
Write-Log -Message ('Failed to enable {0}: {1}' -f $feature, $errorMsg) -Level 'ERROR'
Write-Host ("`n❌ Failed to enable {0}: {1}" -f $feature, $errorMsg) -ForegroundColor Red

# Using string concatenation
Write-Log -Message ('Failed to enable ' + $feature + ': ' + $errorMsg) -Level 'ERROR'
Write-Host ("`n❌ Failed to enable " + $feature + ": " + $errorMsg) -ForegroundColor Red

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Expected behavior

No error or warning should be reported by PSScriptAnalyzer for valid PowerShell syntax using the format operator or string concatenation, regardless of the character following the variable.

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Actual behavior

PSScriptAnalyzer reports:
Variable reference is not valid. ':' was not followed by a valid variable name character. Consider using ${} to delimit the name.

This occurs even when using the format operator (-f) or string concatenation, which are valid and idiomatic PowerShell.

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If an unexpected error was thrown then please report the full error details using e.g. $error[0] | Select-Object *

No unexpected error thrown; this is a linter false positive.

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Environment data

> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      7.3.6
PSEdition                      Core
GitCommitId                    7.3.6
OS                             Microsoft Windows 10.0.19045
Platform                       Win32NT
...

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

2.10.0

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Additional context:
This issue also appears in the VS Code PowerShell extension, which integrates PSScriptAnalyzer for diagnostics. Please coordinate with the extension maintainers if needed.