Wow so null very static such empty

wow

$ powershell ./wut.ps1
String is null
String is null
String is empty

wut.ps1

function main() {
    if ($true) {
        $s = $null
    } else {
        $s = "string"
    }
    if ($s -eq $null) { Write-Host "String is null" }
    if ($s -eq "") { Write-Host "String is empty" }
    do_something_boring $s
}

function do_something_boring($s) {
    if ($s -eq $null) { Write-Host "String is null" }
    if ($s -eq "") { Write-Host "String is empty" }
    do_something_obvious $s
}

function do_something_obvious([string] $s) {
    if ($s -eq $null) { Write-Host "String is null" }
    if ($s -eq "") { Write-Host "String is empty" }
}

main