Online PHP editor | output for svfeO

@ 2026-01-31T11:46:56Z

<?php

enum SpecialReturnValue
{
    case NoReturn;
    case ReturnWithoutValue;
    case ReturnDollarThis;
    case ReturnVoid;
    case ReturnNever;
}

class ShouldTypeError
{
    public $uniqueId;
    public function __construct($returnValue)
    {
        static $uniqueId = 0;
        $this->uniqueId = $uniqueId;
        $uniqueId++;
        
        if ($returnValue !== SpecialReturnValue::NoReturn) {
            if ($returnValue === SpecialReturnValue::ReturnWithoutValue) {
                return;
            } elseif ($returnValue === SpecialReturnValue::ReturnDollarThis) {
                return $this;
            } elseif ($returnValue === SpecialReturnValue::ReturnVoid) {
                return void;
            } elseif ($returnValue === SpecialReturnValue::ReturnNever) {
                return never;
            }
            
            return $returnValue;
        }
    }
}

const SOMECONST = 'Const hello';

enum SomeEnum 
{
    case Hearts;
    case Diamonds;
    case Clubs;
    case Spades;
}

function SomeFunction()
{
}

$SomeFunctionClosure = function()
{
};

$SomeFunctionFirstClassCallable = SomeFunction(...);

$someFunctionClosureFromCallabe = Closure::fromCallable('SomeFunction');

$arrowFunction = fn($a) => $a;

$testcases = [
    SpecialReturnValue::NoReturn,
    SpecialReturnValue::ReturnWithoutValue,
    SpecialReturnValue::ReturnDollarThis,
    new ShouldTypeError(SpecialReturnValue::NoReturn),

    SOMECONST,    
    'abc',
    1,
    1.23,
    null,
    true,
    false,
    
    ['a', 'b', 'c'],
    [6 => 'six', 7 => 'seven', 67 => 'six seven'],
    ['a' => 'a', 'b' => 'b', 'c' => 'c', 0 => 'Zero'],
    
    SpecialReturnValue::ReturnVoid,
    SpecialReturnValue::ReturnNever,

    SomeEnum::Spades,
    
    function() {},
    $SomeFunctionClosure,
    $SomeFunctionFirstClassCallable,
    $someFunctionClosureFromCallabe,
    $arrowFunction,
    
    new DateTimeImmutable(),
    fopen('php://memory', 'w+'),
];

foreach($testcases as $testcase) {
    echo "--------------[ TESTCASE ]--------------\n";
    var_dump($testcase);
    echo "\n";
    
    try {
        $didReturn = new ShouldTypeError($testcase);
        
        if ($testcase === SpecialReturnValue::NoReturn) {
            echo "Success: without a return statement is always valid.\n";
        } elseif ($testcase === SpecialReturnValue::ReturnWithoutValue) {
            echo "Success: a return statement without a value is always valid.\n";
        } elseif ($testcase === SpecialReturnValue::ReturnDollarThis) {
            echo "Dubious: return \$this is dubious.\n";
            echo "- it fullfills the return type, so it could be allowed.\n";
            echo "- but returning anything from a constructor is nonsense, because it is discarded by \"new\".\n";
            echo "  As shown by the fourth testcase new SomeTypeError(SpecialReturnValue::NoReturn).\n";
        } else {
            echo "Error: why is it not a return TypeError?\n";
        }
        
        if ($didReturn instanceof ShouldTypeError) {
            echo "Created uniqueId ".$didReturn->uniqueId."\n";
        } else {
            echo "Failed to new a ShouldTypeError.\n";
        }
    } catch (Throwable $ex) {
        echo "Success: throwable: ".$ex->getMessage()."\n";
    }
}

Output for 8.5.2: --------------[ TESTCASE ]-------------- enum(SpecialReturnValue::NoReturn) Success: without a return statement is always valid. Created uniqueId 1 --------------[ TESTCASE ]-------------- enum(SpecialReturnValue::ReturnWithoutValue) Success: a return statement without a value is always valid. Created uniqueId 2 --------------[ TESTCASE ]-------------- enum(SpecialReturnValue::ReturnDollarThis) Dubious: return $this is dubious. - it fullfills the return type, so it could be allowed. - but returning anything from a constructor is nonsense, because it is discarded by "new". As shown by the fourth testcase new SomeTypeError(SpecialReturnValue::NoReturn). Created uniqueId 3 --------------[ TESTCASE ]-------------- object(ShouldTypeError)#8 (1) { ["uniqueId"]=> int(0) } Error: why is it not a return TypeError? Created uniqueId 4 --------------[ TESTCASE ]-------------- string(11) "Const hello" Error: why is it not a return TypeError? Created uniqueId 5 --------------[ TESTCASE ]-------------- string(3) "abc" Error: why is it not a return TypeError? Created uniqueId 6 --------------[ TESTCASE ]-------------- int(1) Error: why is it not a return TypeError? Created uniqueId 7 --------------[ TESTCASE ]-------------- float(1.23) Error: why is it not a return TypeError? Created uniqueId 8 --------------[ TESTCASE ]-------------- NULL Error: why is it not a return TypeError? Created uniqueId 9 --------------[ TESTCASE ]-------------- bool(true) Error: why is it not a return TypeError? Created uniqueId 10 --------------[ TESTCASE ]-------------- bool(false) Error: why is it not a return TypeError? Created uniqueId 11 --------------[ TESTCASE ]-------------- array(3) { [0]=> string(1) "a" [1]=> string(1) "b" [2]=> string(1) "c" } Error: why is it not a return TypeError? Created uniqueId 12 --------------[ TESTCASE ]-------------- array(3) { [6]=> string(3) "six" [7]=> string(5) "seven" [67]=> string(9) "six seven" } Error: why is it not a return TypeError? Created uniqueId 13 --------------[ TESTCASE ]-------------- array(4) { ["a"]=> string(1) "a" ["b"]=> string(1) "b" ["c"]=> string(1) "c" [0]=> string(4) "Zero" } Error: why is it not a return TypeError? Created uniqueId 14 --------------[ TESTCASE ]-------------- enum(SpecialReturnValue::ReturnVoid) Success: throwable: Undefined constant "void" --------------[ TESTCASE ]-------------- enum(SpecialReturnValue::ReturnNever) Success: throwable: Undefined constant "never" --------------[ TESTCASE ]-------------- enum(SomeEnum::Spades) Error: why is it not a return TypeError? Created uniqueId 17 --------------[ TESTCASE ]-------------- object(Closure)#12 (3) { ["name"]=> string(22) "{closure:/in/svfeO:84}" ["file"]=> string(9) "/in/svfeO" ["line"]=> int(84) } Error: why is it not a return TypeError? Created uniqueId 18 --------------[ TESTCASE ]-------------- object(Closure)#1 (3) { ["name"]=> string(22) "{closure:/in/svfeO:51}" ["file"]=> string(9) "/in/svfeO" ["line"]=> int(51) } Error: why is it not a return TypeError? Created uniqueId 19 --------------[ TESTCASE ]-------------- object(Closure)#2 (1) { ["function"]=> string(12) "SomeFunction" } Error: why is it not a return TypeError? Created uniqueId 20 --------------[ TESTCASE ]-------------- object(Closure)#3 (1) { ["function"]=> string(12) "SomeFunction" } Error: why is it not a return TypeError? Created uniqueId 21 --------------[ TESTCASE ]-------------- object(Closure)#4 (4) { ["name"]=> string(22) "{closure:/in/svfeO:59}" ["file"]=> string(9) "/in/svfeO" ["line"]=> int(59) ["parameter"]=> array(1) { ["$a"]=> string(10) "<required>" } } Error: why is it not a return TypeError? Created uniqueId 22 --------------[ TESTCASE ]-------------- object(DateTimeImmutable)#13 (3) { ["date"]=> string(26) "2026-01-31 12:59:15.025949" ["timezone_type"]=> int(3) ["timezone"]=> string(16) "Europe/Amsterdam" } Error: why is it not a return TypeError? Created uniqueId 23 --------------[ TESTCASE ]-------------- resource(5) of type (stream) Error: why is it not a return TypeError? Created uniqueId 24

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