Question

Most of my recent experience is in Java, and I was quite surprised the following PHP code did not throw a compile-time error:

<?php
class Test { }
$a = new Test('foo', true, false, 18320);

Is there any way to force this to be a syntax or compile-time error?

Answer 1

PHP, being a very loosely-typed dynamic language, always allows you to pass any set and any number of arguments to a function or constructor call without error, unless type hints in their definitions aren’t met by the arguments passed; for instance, this won’t work:

class Test {
    public function __construct(array $a, $b, $c, $d) {}
}

// Catchable fatal error: Argument 1 passed to Test::__construct()
// must be an array, string given
$a = new Test('foo', true, false, 18320);

But even then, that’s not going to cause a syntax error either — that’s a fatal error at runtime.

The closest you can get is to enforce the checks at runtime within the function or method bodies.