@psalm-external-mutation-free$this may still change; mutating *other* objects (parameters, globals) is
forbidden.
References:
- Psalm supported_annotations.md: @psalm-external-mutation-free| Analyzer | Version | Result | Diagnostics |
|---|---|---|---|
| phan | 6.0.10Phan 6.0.10 php-ast version 1.1.3 PHP version used to run Phan: 8.5.11 | Not enforced | No diagnostics reported.
|
| phpstan | 2.3.1PHPStan - PHP Static Analysis Tool 2.3.1 | Not enforced | No diagnostics reported.
|
| psalm | 6.20.0Psalm 6.20.0@804f03c0c183d149fcd4b8c7c0c9b3fbf836d34c next: 7.0.0-rc2 |
Enforced | phpdoc_advanced_psalm_external_mutation_free.php:30: Cannot assign to a property from a mutation-free context [ImpurePropertyAssignment]
|
| mago | 1.57.0mago 1.57.0 | Not enforced | No diagnostics reported.
|
| mir | 0.87.0mir 0.87.0 | Enforced | phpdoc_advanced_psalm_external_mutation_free.php:30: ImpurePropertyAssignment: Assigning to property value of a parameter in a pure or external-mutation-free context [MIR1700]
|
| phpantom | 0.11.1phpantom_lsp 0.11.1 | Not enforced | No diagnostics reported.
|
| intelephense | 1.18.5intelephense 1.18.5 | Not enforced | No diagnostics reported.
|
| phpactor | 2026.10.07.0Phpactor 2026.10.07.0 | Not enforced | No diagnostics reported.
|
| phpy | 1.0.19409phpy 1.0.19409 | Not enforced | No diagnostics reported.
|
| qodana | 262.10968.76PhpStorm 262.10968.76 | Not enforced | No diagnostics reported.
|
| noverify | 0.5.5NoVerify, version 0.5.5: built on: 2025.04.22 14:36:46 OS: r-kuchinskas arm64 Commit: 4774b82f8adc53fbef38f95e97af4b953b4d1529 | Not enforced | No diagnostics reported.
|
| steins | 0.1.8steins 0.1.8 (2026-09-21 revision 76306a9) | Not enforced | No diagnostics reported.
|
| phpstan-strict | 2.3.1PHPStan - PHP Static Analysis Tool 2.3.1 | Not enforced | No diagnostics reported.
|
| psalm-next | 7.0.0-rc2Psalm 7.0.0-rc2@20339e3fe5b8d03bcd8061030eb2a83ad50e5783 | Enforced | phpdoc_advanced_psalm_external_mutation_free.php:30: The context is read-props|write-this-props|write-refs but property assignment to Conformance\Tests\PhpdocAdvancedPsalmExternalMutationFree\Cell::$value requires write-props [ImpurePropertyAssignment] phpdoc_advanced_psalm_external_mutation_free.php:30: The context is read-props|write-this-props|write-refs but property assignment requires write-props [ImpurePropertyAssignment]
|
<?php
declare(strict_types=1);
namespace Conformance\Tests\PhpdocAdvancedPsalmExternalMutationFree;
/**
* Cross-tool handling of `@psalm-external-mutation-free`.
*
* `$this` may still change; mutating *other* objects (parameters, globals) is
* forbidden.
*
* References:
* - Psalm supported_annotations.md: `@psalm-external-mutation-free`
*/
final class Cell
{
public string $value = '';
/**
* @psalm-external-mutation-free
*/
public function copyFrom(Cell $other): void // T: @psalm-external-mutation-free
{
// Own state is allowed under external-mutation-free.
$this->value = $other->value; // V
// Mutating a parameter is not.
$other->value = 'stolen'; // E?: external object write contradicts @psalm-external-mutation-free
}
}