Why specify void return type in PHP7?

The void return type was introduced in PHP 7.1.

By indicating that a method or function has a return type of void , we indicate that it does not return anything , being valid, for example:

function noReturn() : void
{
   // code
}

function noReturn2() : void
{
   // code
   return ;
}

Indicating the void return type improves the readability of the code . We can look at the method or function and, without having to go into its body, know that it doesn't have return statements returning some type of content.

Edited.

If our code editor allows us to "fold code", for a quick look, we will quickly appreciate the improvement in readability that specifying return types gives us , for example, we could have:

class Xxx {
    function getName() : string
    {...}

    function noReturn() : void
    {...}

    function noReturn2() : void
    {...}
}

where it is clear that without having to see the implementation of the methods, or use comments, we know if the methods return something or not, and the type if so.

Sources consulted:

php.net - Pseudotypes and variables used
php.net - New features
php.net - Return values
​​Upgrade to PHP7

According to the PHP documentation in version 7.1 this feature has been introduced.

EXAMPLE 1

function metodo(): void
{
    return "Hola";
}

echo metodo();

It will show this error

Fatal error : A void function must not return a value in [...][...] on line 6

Because as its name indicates, a method voidis thinking not to return values

Reference http://php.net/manual/es/migration71.new-features.php

Since a method of type voidcannot return a value then this example might give a better example of its use

$value;
function metodo($value): void
{
    if($value > 1000){
        echo 1;
    }else{
        echo 2;
    }
}

echo metodo(200);