function.uselessReturnValue

Code example

<?php declare(strict_types = 1);

$output = print_r(['name' => 'John', 'age' => 30]);

Why is it reported?

The return value of a function like print_r(), var_export(), or highlight_string() is being used, but without passing true as the second parameter, these functions print their output directly and return a useless value (true for print_r(), null for var_export()).

In the example above, print_r() is called without the $return parameter set to true, so it prints the array directly to the output and returns true. Assigning or using this return value is meaningless.

How to fix it

Pass true as the second parameter to return the output as a string instead of printing it:

 <?php declare(strict_types = 1);

-$output = print_r(['name' => 'John', 'age' => 30]);
+$output = print_r(['name' => 'John', 'age' => 30], true);

Or if the intent is only to print the value, do not use the return value:

 <?php declare(strict_types = 1);

-$output = print_r(['name' => 'John', 'age' => 30]);
+print_r(['name' => 'John', 'age' => 30]);