null Or Boolean As Array

<?php


var_dump(null [[]]); // NULL
var_dump(true [[]]); // NULL
var_dump(false [[]]); // NULL

var_dump( [][[]]); // fatal error

Null and booleans support the array syntax, but always return NULL as value. Since PHP 7.4, they also report a warning, as this is not good code.

Arrays also report errors when the key type is not valid, such as another array or an object.

Interestingly, Null and boolean accept illegal keys, with a simple warning.

See Also

• Accessing index on literals [Try me]

PHP Error Messages

• Trying to access array offset on null

• Trying to access array offset on false

• Trying to access array offset on true

PHP Features

• null

• boolean

• array-syntax

Last updated: 14 July 2026