Intersection types in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a function that accepts a parameter which must implement both interfaces A and B.

PHP

<?php
interface A {}
interface B {}

function test([1] $param) {
    // function body
}
?>

Drag options to blanks, or click blank then click option'

AA or B

BA|B

CA,B

DA&B

Attempts:

3 left

💡 Hint

Common Mistakes

Using | instead of & which means union type, not intersection.

Separating interfaces with commas or words like 'or'.

In PHP, intersection types are declared using the & symbol between interface names.

2fill in blank

medium

Complete the code to declare a variable with an intersection type of interfaces X and Y.

PHP

<?php
interface X {}
interface Y {}

/** @var [1] */
$obj;
?>

Drag options to blanks, or click blank then click option'

AX|Y

BX&Y

CX,Y

DX or Y

Attempts:

3 left

💡 Hint

Common Mistakes

Using | which means either type, not both.

Using commas or words instead of &.

Intersection types use & to specify that the variable must implement both interfaces.

3fill in blank

hard

Fix the error in the function parameter type declaration to correctly use intersection types.

PHP

<?php
interface M {}
interface N {}

function example([1] $param) {
    // code
}
?>

Drag options to blanks, or click blank then click option'

AM&N

BM,N

CM|N

DM or N

Attempts:

3 left

💡 Hint

Common Mistakes

Using union type | instead of intersection &.

Separating interfaces with commas.

The correct syntax for intersection types uses & between interface names.

4fill in blank

hard

Fill both blanks to declare a function that accepts a parameter implementing interfaces P and Q, and returns a value of the same intersection type.

PHP

<?php
interface P {}
interface Q {}

function process([1] $input): [2] {
    return $input;
}
?>

Drag options to blanks, or click blank then click option'

AP&Q

BP|Q

CQ&P

DP,Q

Attempts:

3 left

💡 Hint

Common Mistakes

Using union type | or commas in type declarations.

Mismatching parameter and return types.

Both the parameter and return type must use the intersection type with &.

5fill in blank

hard

Fill all three blanks to declare a class implementing interfaces U and V, and a function that accepts a parameter with the same intersection type.

PHP

<?php
interface U {}
interface V {}

class MyClass implements [1] {
    public function handle([2] $param): void {
        // handle param
    }
}

function callHandle([3] $obj) {
    $obj->handle($obj);
}
?>

Drag options to blanks, or click blank then click option'

AU&V

BU|V

CV&U

DU,V

Attempts:

3 left

💡 Hint

Common Mistakes

Using & in the implements clause instead of commas.

Using | or commas in intersection type declarations instead of &.

The class implements interfaces U and V using 'U,V', and the parameter types use the intersection type 'U&V'.