NoDiscard

Description: Indicates that the return value of a function or method should not be discarded. Emits a warning if the return value is unused.

Namespace: Built-in PHP (no import required)

Since: PHP 8.5

Usage

#[\NoDiscard('as processing might fail for individual items')]
function processItems(array $items): array
{
    // Returns an array of results/errors per item
    return [];
}

processItems($items); // Warning: return value should be used or cast as (void)

$results = processItems($items); // OK

Parameters

Parameter	Type	Description
$message	?string	Optional message explaining why the return value should not be discarded

Intentionally discarding the return value

Use a (void) cast to suppress the warning explicitly:

(void) processItems($items); // Suppresses the warning — PHP 8.5+

For cross-version compatibility (below PHP 8.5), use a $_ variable:

$_ = processItems($items); // No warning on any PHP version

Note: #[\NoDiscard] can be added even when targeting PHP 8.4 or below — it simply has no effect on older versions.

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