Allow limiting who can inherit/implement a class

[muglug]

/**
 * @psalm-inheritors FooClass|BarClass
 */
class BaseClass {}

class FooClass extends BaseClass {
  public function thing(string $s) : void { return $s . "hello"; }
}

class BarClass extends BaseClass {
  public function thing(int $i) : string { return $i . "hello"; }
}

class BazClass extends BaseClass {} // this is an error

function f1(BaseClass $c) : string {
  switch (get_class($c)) {
    case FooClass:class:
      return $c->thing("me");
    case BarClass:class:
      return $c->thing(5);
  }
}

function f2(BaseClass $c) : string { // this is an error as not all paths are met
  switch (get_class($c)) {
    case FooClass:class:
      return $c->thing("me");
  }
}

[kkmuffme]

Would be nice if there was a wildcard for the namespace, e.g. FooClass of any namespace can extend it

[orklah]

This would be a pain to implement for a very niche usage I think.

I'll close this btw, it has been implemented