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Do not report ?? null / ??= null as unnecessary when evaluating the right side has side effects #6418

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Merged
staabm merged 3 commits into from
Sep 12, 2026
+284 −2
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Do not report ?? null / ??= null as unnecessary when evaluating the right side has side effects #6418

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9b6286e
Do not report `?? null` / `??= null` as unnecessary when evaluating t…
phpstan-bot Sep 11, 2026
5d68bc9
Make the null-coalesce side-effect test data PHP version independent
phpstan-bot Sep 11, 2026
85dd864
Cover every node kind checked by NullCoalesceRule::containsAssign()
phpstan-bot Sep 12, 2026
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Make the null-coalesce side-effect test data PHP version independent 
The data file declared `null` return types natively, which is only a type
on PHP 8.2+. With a lower `phpVersion` (the tests run on PHP 7.4 too) the
same declaration resolves to an object type named `null`, so the right
side isn't null and the pure-function case wasn't reported.

Declare the null return types in PHPDoc instead so every case exercises
what it claims on all analysed PHP versions.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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@phpstan-bot @claude @staabm
2 people authored and staabm committed Sep 12, 2026
commit 5d68bc9b30a736983becb125aa4dc8ecad56036c
12 changes: 6 additions & 6 deletions tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -515,27 +515,27 @@ public function testUnnecessaryNullCoalesceSideEffects(): void
$this->analyse([__DIR__ . '/data/unnecessary-null-coalesce-side-effects.php'], [
[
'Coalesce operator ??= is unnecessary because the left side is always set and the right side is null.',
104,
111,
],
[
'Coalesce operator ?? is unnecessary because the left side is always set and the right side is null.',
111,
118,
],
[
'Coalesce operator ?? is unnecessary because the left side is always set and the right side is null.',
116,
123,
],
[
'Coalesce operator ?? is unnecessary because the left side is always set and the right side is null.',
121,
128,
],
[
'Coalesce operator ?? is unnecessary because the left side is always set and the right side is null.',
128,
135,
],
[
'Coalesce operator ?? is unnecessary because the left side is always set and the right side is null.',
133,
140,
],
]);
}
Expand Down
23 changes: 15 additions & 8 deletions tests/PHPStan/Rules/Variables/data/unnecessary-null-coalesce-side-effects.php
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
<?php // lint >= 8.2
<?php

declare(strict_types = 1);

Expand All @@ -8,7 +8,8 @@

const NULL_CONSTANT = null;

function returnsNull(bool $value): null
/** @return null */
function returnsNull(bool $value)
{
if ($value === false) {
throw new LogicException('nope');
Expand All @@ -17,8 +18,11 @@ function returnsNull(bool $value): null
return null;
}

/** @phpstan-pure */
function pureReturnsNull(): null
/**
* @phpstan-pure
* @return null
*/
function pureReturnsNull()
{
return null;
}
Expand All @@ -34,17 +38,20 @@ class Foo
/** @var null */
public $alwaysNull = null;

public function returnsNull(): null
/** @return null */
public function returnsNull()
{
return null;
}

public static function staticReturnsNull(): null
/** @return null */
public static function staticReturnsNull()
{
return null;
}

public function __invoke(): null
/** @return null */
public function __invoke()
{
return null;
}
Expand Down Expand Up @@ -73,7 +80,7 @@ function invokeOnRightSide(Foo $foo): ?string

function closureCallOnRightSide(Foo $foo): ?string
{
$closure = static function (): null {
$closure = static function () {
echo 'side effect';

return null;
Expand Down