Simple multi-type return functions with strict typing and type coercion

TypeCoercion.php

<?php

class MyClass
{
    private $data;

    public function __construct(array $value)
    {
        $this->data = $value;
    }

    public static function __coerce($value)
    {
        if (! is_array($value)) {
            throw new \Exception(
                'Returned value does not match the return type defined.'
            );
        }

        return new self($value);
    }
}

class MRFClass {
    function callMe($name)
    {
        return [$name, 1, 2, 3];
    }
}

/**
 * Call a global function and use type coercion
 * for non-registered return types. 
 *
 * @param  closure $closure    The function to execute. 
 * @param  string  $returnType The registered return type.
 * @param  array   $params     The parameters to pass to the function. 
 * 
 * @return mixed The result of the function to execute.
 */
function multiReturnFunction($closure, $returnType, ...$params)
{
    $val = $closure(...$params);
    
    if (gettype($val) === 'object') {
        if (get_class($val) != $returnType) {
            if (method_exists($returnType, '__coerce')) {
                $val = $returnType::__coerce($val);
            } else {
                throw new \Exception(
                    'Returned value does not match the return type defined, '.
                    'and no __coerce function is visible.'
                );
            }
        }
    } else if (gettype($val) != $returnType) {
        if (method_exists($returnType, '__coerce')) {
            $val = $returnType::__coerce($val);
        } else {
            throw new \Exception(
                'Returned value does not match the return type defined, '.
                'and no __coerce function is visible.'
            );
        }
    }

    return $val;
}

/*
 * Call a class method and use type coercion
 * for non-registered return types. 
 *
 * @param  object  $obj        The object to call the method on.
 * @param  string  $method     The method to call on the object.
 * @param  string  $returnType The registered return type.
 * @param  array   $params     The parameters to pass to the method. 
 * 
 * @return mixed The result of the method to execute.
 */
function multiReturnMethod($obj, $method, $returnType, ...$params)
{
    $val = $obj->{$method}(...$params);
    
    if (gettype($val) === 'object') {
        if (get_class($val) != $returnType) {
            if (method_exists($returnType, '__coerce')) {
                $val = $returnType::__coerce($val);
            } else {
                throw new \Exception(
                    'Returned value does not match the return type defined, '.
                    'and no __coerce function is visible.'
                );
            }
        }
    } else if (gettype($val) != $returnType) {
        if (method_exists($returnType, '__coerce')) {
            $val = $returnType::__coerce($val);
        } else {
            throw new \Exception(
                'Returned value does not match the return type defined, '.
                'and no __coerce function is visible.'
            );
        }
    }

    return $val;
}

$resultingMyClass = multiReturnFunction (
    // Multi return type function.
    function($name, $age) {
        // Here you can return either a MyClass instance, or an array.
        // All other types will throw an exception.

        return [$name, $age];
    },

    // Return Type, any other type will be coerced through this class.
    MyClass::class,

    // Function parameters.
    'Nathan', 23
);

print_r($resultingMyClass);

$resultingMRFClass = multiReturnMethod (
    // The object that we will be calling the
    // class method on.
    new MRFClass(),

    // The class method to call, by name.
    // This can return either a MyClass instance or an array.
    'callMe',

    // The return type to coerce to.
    MyClass::class,

    // The function parameters.
    'Nathan'
);

print_r($resultingMRFClass);

See instructions on usage here: https://stackoverflow.com/questions/48119027/php-override-weak-function-return-type-coercion/49542067#49542067