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phpstan

How to represent a non-empty array?

I tried using intersection of types

/**
 * @param array&nonEmpty $users
 */
function sayHello($users): void {
    echo 'Hello, ' . $users[0];
}

but it complains:

PHPDoc tag @param for parameter $users contains unresolvable type.

(live demo)

If I strip the annotation to just nonEmpty, the error changes to

Parameter $users of function sayHello() has invalid typehint type nonEmpty

I do see the class responsible for the nonEmpty type in the source tree as well as mentioned several times in the tests and issues but I just could not make it work.

Solution

  • Just to provide an answer for those coming from search engines:

    PHPStan now has non-empty-array type you can use. Here is an example.