`new` through a `class-string<T>` property

Group: PHPDoc generics · Category: phpdoc · File: generics_class_string_property_new.php

Instantiating through a class-string<T> held in a property: new ($this->class)() is a T. The class-string generic case is already covered for parameters (phpdoc_advanced_generic_class_string); this asks whether the property read and the new (expr) syntax carry it too. References: - PHPStan / Psalm class-string<T> - https://wiki.php.net/rfc/variable_syntax_tweaks (new with an expression)

Analyzer results

Analyzer	Version	Result	Diagnostics
phan	6.0.11Phan 6.0.11 php-ast version 1.1.3 PHP version used to run Phan: 8.5.11	Enforced	generics_class_string_property_new.php:39: Call to undeclared method \Conformance\Tests\GenericsClassStringPropertyNew\User::missing [PhanUndeclaredMethod] Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported
phpstan	2.3.5PHPStan - PHP Static Analysis Tool 2.3.5	Enforced reported Lv.2+	generics_class_string_property_new.php:39: Call to an undefined method Conformance\Tests\GenericsClassStringPropertyNew\User::missing(). [reported-from-level=2] generics_class_string_property_new.php:39: Parameter #1 (mixed) of echo cannot be converted to string. [reported-from-level=10] With strict-rules generics_class_string_property_new.php:39: Call to an undefined method Conformance\Tests\GenericsClassStringPropertyNew\User::missing(). generics_class_string_property_new.php:39: Parameter #1 (mixed) of echo cannot be converted to string. Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported
psalm	6.20.9Psalm 6.20.9@f67170ac3c3b931f5088681e21d6c8babc601c08 next: 7.0.4	Enforced	generics_class_string_property_new.php:36: Cannot safely instantiate class Conformance\Tests\GenericsClassStringPropertyNew\User with "new $class_name" as its constructor might change in child classes [UnsafeInstantiation] generics_class_string_property_new.php:38: Cannot safely instantiate class Conformance\Tests\GenericsClassStringPropertyNew\User with "new $class_name" as its constructor might change in child classes [UnsafeInstantiation] generics_class_string_property_new.php:39: Argument 1 of echo cannot be mixed, expecting string [MixedArgument] generics_class_string_property_new.php:39: Method Conformance\Tests\GenericsClassStringPropertyNew\User::missing does not exist [UndefinedMethod] Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported
mago	1.59.0mago 1.59.0	Enforced	generics_class_string_property_new.php:39: Method `missing` does not exist on type `Conformance\Tests\GenericsClassStringPropertyNew\User`. [non-existent-method] generics_class_string_property_new.php:39: The first value for `echo` is too general. [mixed-argument] Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported
mir	0.91.0mir 0.91.0	Enforced	generics_class_string_property_new.php:39: UndefinedMethod: Method Conformance\Tests\GenericsClassStringPropertyNew\User::missing() does not exist [MIR0004] Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported
phpantom	0.11.1phpantom_lsp 0.11.1	Enforced	generics_class_string_property_new.php:37: Cannot verify method 'name' — type of '$user' could not be resolved [unresolved_member_access] generics_class_string_property_new.php:39: Cannot verify method 'missing' — type of '$made' could not be resolved [unresolved_member_access] Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported Expectation diff Line 37: Expected valid value to be accepted, got ["Cannot verify method 'name' — type of '$user' could not be resolved [unresolved_member_access]"]
intelephense	1.18.5intelephense 1.18.5	Enforced	generics_class_string_property_new.php:39: Expected type 'string\|Stringable\|null'. Found 'mixed'. [P1006] generics_class_string_property_new.php:39: Undefined method 'missing'. [P1013] Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported
phpactor	2026.10.07.0Phpactor 2026.10.07.0	Enforced	generics_class_string_property_new.php:39: Method "missing" does not exist on class "Conformance\Tests\GenericsClassStringPropertyNew\User" [missing_member] Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported
phpy	1.0.19490phpy 1.0.19490	Enforced	generics_class_string_property_new.php:39: Call to unknown method: Conformance\Tests\GenericsClassStringPropertyNew\User::missing() Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported
qodana	262.11879.104PhpStorm 262.11879.104	Not enforced	No diagnostics reported. Recognition: spelling resolved Enforcement: 0/1 of the expected violations reported Expectation diff Line 39: Expected 1 error(s)
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. Recognition: spelling resolved Enforcement: 0/1 of the expected violations reported Expectation diff Line 39: Expected 1 error(s)
steins	0.1.8steins 0.1.8 (2026-09-21 revision 76306a9)	Not enforced	No diagnostics reported. Recognition: spelling resolved Enforcement: 0/1 of the expected violations reported Expectation diff Line 39: Expected 1 error(s)
phpstan-strict	2.3.5PHPStan - PHP Static Analysis Tool 2.3.5	Enforced	generics_class_string_property_new.php:39: Call to an undefined method Conformance\Tests\GenericsClassStringPropertyNew\User::missing(). generics_class_string_property_new.php:39: Parameter #1 (mixed) of echo cannot be converted to string. Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported
psalm-next	7.0.4Psalm 7.0.4@fa5b1f6e665cb743838ffd865b8fc96207f9409f	Enforced	generics_class_string_property_new.php:36: Cannot safely instantiate class Conformance\Tests\GenericsClassStringPropertyNew\User with "new $class_name" as its constructor might change in child classes [UnsafeInstantiation] generics_class_string_property_new.php:38: Cannot safely instantiate class Conformance\Tests\GenericsClassStringPropertyNew\User with "new $class_name" as its constructor might change in child classes [UnsafeInstantiation] generics_class_string_property_new.php:39: Argument 1 of echo cannot be mixed, expecting string [MixedArgument] generics_class_string_property_new.php:39: Method Conformance\Tests\GenericsClassStringPropertyNew\User::missing does not exist [UndefinedMethod] Recognition: spelling resolved Enforcement: 1/1 of the expected violations reported

Source

<?php

declare(strict_types=1);

namespace Conformance\Tests\GenericsClassStringPropertyNew;

/**
 * `new` through a `class-string<T>` property.
 *
 * Instantiating through a `class-string<T>` held in a property:
 * `new ($this->class)()` is a T. The class-string generic case is already
 * covered for parameters (phpdoc_advanced_generic_class_string); this asks
 * whether the property read and the `new (expr)` syntax carry it too.
 *
 * References:
 * - PHPStan / Psalm class-string<T>
 * - https://wiki.php.net/rfc/variable_syntax_tweaks (new with an expression)
 */

final class User
{
    public function name(): string
    {
        return 'user';
    }
}

final class Factory
{
    /** @var class-string<User> */
    public string $class = User::class; // T: class-string<User>
}

function instantiates(Factory $factory): void
{
    $user = new ($factory->class)(); // E?[noise]: UnsafeInstantiation
    echo $user->name(); // V
    $made = new ($factory->class)(); // E?[noise]: UnsafeInstantiation
    echo $made->missing(); // E: the instance is a User
}

new through a class-string<T> property

Analyzer results

Source

`new` through a `class-string<T>` property