A function that displays errors during validated parameter type changes

Show-ThisPSOddity.ps1

function Show-ThisPsOddity {
    param(
        [Parameter(Mandatory=$true)][ValidateNotNullOrEmpty()][ValidateSet("foo", "bar", "baz", "match")][String]$UserInput,
        [ValidateRange(1,2)][int]$Variant = 1  
    )

    switch($variant) {
            
        1 { if($UserInput -eq "match"){ $UserInput = @("foo", "bar", "baz") } }
                   
        2 { if($UserInput -eq "match"){ [array]$UserInput = "foo", "bar", "baz" } }

    }  
    
    "Before the loop `$UserInput is $UserInput of type $(if($UserInput -is [array]){$UserInput.GetType().BaseType}else{$UserInput.GetType()})"

    foreach($item in $UserInput) { "In the loop `$item is $item of type $(if($item -is [array]){$item.GetType().BaseType}else{$item.GetType()})" }     

}