/**
 * @[psalm-|phpstan-]template T
 * @[psalm-|phpstan-]param class-string<T> $class
 * @[psalm-|phpstan-]return T
 */
function instantiator(string $class) {
    return new $class();
}

class Foo {}

$a = instantiator(Foo::class); // Psalm knows the result is an object of type Foo

    /**
     * @[psalm-|phpstan-]template T as Exception
     * @[psalm-|phpstan-]param T::class $type
     * @return T
     */
    function a(string $type): Exception
    {
        return new $type;
    }

    $collection = new FooCollection();
    
    // its now a type of "Foobar"
    $foobar = $collection->getValue();
    $foobar->get<caret>Foobar(); // method is clickable and autocompletes

    /**
     * @[psalm-|phpstan-]template T
     */
    class Collection
    {
        /**
         * @[psalm-|phpstan-]return T
         */
        public function getValue() {}
    }

    /**
     * @[psalm-|phpstan-]extends Collection<Foobar>
     */
    class FooCollection extends Collection {}

    class Foobar
    {
        public function getFoobar() {}
    }

    a(['<caret>' => ''])

    /**
     * @[psalm-|phpstan-]param array{foo: string, bar: int} $type
     */
    function a(array $type): Exception
    {
    }

/**
 * @template T
 */
class Map
{
    /**
     * @param array<string, T>
     */
    public function __construct(array $data = []) {}
    /**
     * @return T
     */
    public function get(string $key) {}
    /**
     * @param T $value
     */
    public function set(string $key, $value): void {}
}
// Automatically inferred as Map<string>
$map = new Map([0 => 'Foo', 1 => 'Bar']);
$map->set(2, true); // Expected string

    class Assert
    {
        /**
         * @psalm-template ExpectedType of object
         * @psalm-param class-string<ExpectedType> $class
         * @psalm-assert ExpectedType $value
         */
        public static function isInstanceOf($value, $class, $message = '')
        {
        }
    }

/**
* @param array{'foo': int, "bar": string} $a
* @param array{0: int, 1?: int} $a
* @param array{int, int} $a
* @param array{foo: int, bar: string} $a
* @param array{foo:string, bar:?int} $a
*/

 /** @var array<int, string> */