defining generic return for a method/function in php with phpdocblock

Question

Is there a way to specify that a function will return an object of a specific type, where the type is the string of one of the parameters?

e.g.

/**
 * @return object<$class>
 */
public function create(string $class): object {
 ... some factory stuff
}

so that vscode or phpstorm will know that when I do

$myvar = X::create('MyClass');

$myvar will be of type MyClass and I'll have the proper intellisense/autocompletion for it?

I created a bug report for vscode . since it cannot handle Generics properly. github.com/bmewburn/vscode-intelephense/issues/2144 unless there is some other way to do it for it. — useless
– useless, Commented Feb 16, 2022 at 22:18
unfortunately at the current date a team member of vscode's intelephense has anwer Generics are not currently supported. — useless
– useless, Commented Feb 17, 2022 at 15:31

useless · Accepted Answer · 2023-04-13 12:35:00Z

7

This could work using templates like this:

/**
 * @template T of object
 * @psalm-param class-string<T> $a
 * @param class-string<T> $a
 * @return T
 */
function foo($a)
{
    return $a;
}

But I don't know whether VSCode already supports that. PhpStorm for example doesn't know how to handle the returned value properly

edited Apr 13, 2023 at 12:35

useless

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answered Feb 16, 2022 at 12:17

Nico Haase

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3 Comments

useless Over a year ago

in your example the parameter $a is also the returned instance. I need parameter to be a string that describes the class returned. foo('stdClass') should be inferred as: foo($c:string):stdClass, and foo('DateTime') as foo($c:string):DateTime

Nico Haase Over a year ago

@useless please see my revised code. This time, I've checked it using PHPStan before answering :P

useless Over a year ago

I had already find that, unfortunately vscode is not recognizing the return type.

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