[DependencyInjection] Do not add return in LazyClosure when return type of closure is void

[ruudk]

Q	A
Branch?	6.3
Bug fix?	yes
New feature?	no
Deprecations?	no
Tickets
License	MIT
Doc PR

The LazyClosure was introduced in #49639 and generates PHP code using reflection.

It works, but when the callable has a void return type, it would produce code like this:

return $container->services['closure2'] = (new class(fn() => new \Symfony\Component\DependencyInjection\Tests\Compiler\FooVoid()) extends \Symfony\Component\DependencyInjection\Argument\LazyClosure {
    public function __invoke(string $name) : void
    {
        // the `return` below causes the error
        return $this->service->__invoke(...\func_get_args());
    }
})->__invoke(...);

That return statement before calling the $this->service is not allowed and causes an error:

Compile Error: A void function must not return a value

/cc @nicolas-grekas

[nicolas-grekas]

Thank you @ruudk.