class-stringclass-string is a refinement of string, so a @return class-string
value always satisfies a native string parameter — analyzers that do not
model it still fall back to string. Analyzers that enforce the refinement
additionally reject a literal that is not a known class name.
References:
- PHPStan TypeNodeResolver class-string resolves to ClassStringType| 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 | Enforced | phpdoc_advanced_fallback_class_string.php:46: Possible use of a classlike '\not a class name' with an invalid FQSEN. [PhanInvalidFQSENInClasslike] phpdoc_advanced_fallback_class_string.php:46: Argument 1 ($value) is 'not a class name' of type string but \Conformance\Tests\PhpdocAdvancedFallbackClassString\acceptsClassString() takes class-string (no real type) defined at /Users/megurine/repo/php/php-typing-conformance/conformance/tests/phpdoc_advanced_fallback_class_string.php:34 (the inferred real argument type has nothing in common with the parameter's phpdoc type) [PhanTypeMismatchArgumentProbablyReal]
|
| phpstan | 2.3.1PHPStan - PHP Static Analysis Tool 2.3.1 | Enforced reported Lv.5+ | phpdoc_advanced_fallback_class_string.php:46: Parameter #1 $value of function Conformance\Tests\PhpdocAdvancedFallbackClassString\acceptsClassString expects class-string, string given. [reported-from-level=5] With strict-rulesphpdoc_advanced_fallback_class_string.php:46: Parameter #1 $value of function Conformance\Tests\PhpdocAdvancedFallbackClassString\acceptsClassString expects class-string, string given.
|
| psalm | 6.20.0Psalm 6.20.0@804f03c0c183d149fcd4b8c7c0c9b3fbf836d34c next: 7.0.0-rc2 |
Enforced | phpdoc_advanced_fallback_class_string.php:46: Argument 1 of Conformance\Tests\PhpdocAdvancedFallbackClassString\acceptsClassString expects class-string, but parent type 'not a class name' provided [ArgumentTypeCoercion] phpdoc_advanced_fallback_class_string.php:46: Class, interface or enum named not a class name does not exist [UndefinedClass]
|
| mago | 1.57.0mago 1.57.0 | Enforced | phpdoc_advanced_fallback_class_string.php:46: Possible argument type mismatch for argument #1 of `Conformance\Tests\PhpdocAdvancedFallbackClassString\acceptsClassString`: expected `class-string`, but possibly received `string('not a class name')`. [possibly-invalid-argument]
|
| mir | 0.87.0mir 0.87.0 | Widened to string | No diagnostics reported.
|
| phpantom | 0.11.1phpantom_lsp 0.11.1 | Not enforced | No diagnostics reported.
|
| intelephense | 1.18.5intelephense 1.18.5 | Widened to string | 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 | Widened to string | No diagnostics reported.
Notes: Keeps the name — its messages expect 'class-string', and it types `::class` arguments as `class-string` — but any string satisfies it: `'not a class name'` passes, while an int or an array is rejected. What is checked is that the argument is a string. |
| noverify | 0.5.5NoVerify, version 0.5.5: built on: 2025.04.22 14:36:46 OS: r-kuchinskas arm64 Commit: 4774b82f8adc53fbef38f95e97af4b953b4d1529 | Widened to string | No diagnostics reported.
|
| steins | 0.1.8steins 0.1.8 (2026-09-21 revision 76306a9) | Widened to string | No diagnostics reported.
Notes: `class-string` lowers to `ContractTy::StrOpaque` (ADR-0038: non-extensional membership) rather than checking the string names a declared class, so it accepts any string and rejects only non-strings — the same acceptance a bare `string` parameter gives. |
| phpstan-strict | 2.3.1PHPStan - PHP Static Analysis Tool 2.3.1 | Enforced | phpdoc_advanced_fallback_class_string.php:46: Parameter #1 $value of function Conformance\Tests\PhpdocAdvancedFallbackClassString\acceptsClassString expects class-string, string given.
|
| psalm-next | 7.0.0-rc2Psalm 7.0.0-rc2@20339e3fe5b8d03bcd8061030eb2a83ad50e5783 | Enforced | phpdoc_advanced_fallback_class_string.php:46: Argument 1 of Conformance\Tests\PhpdocAdvancedFallbackClassString\acceptsClassString expects class-string, but parent type 'not a class name' provided [ArgumentTypeCoercion] phpdoc_advanced_fallback_class_string.php:46: Class, interface or enum named not a class name does not exist [UndefinedClass]
|
<?php
declare(strict_types=1);
namespace Conformance\Tests\PhpdocAdvancedFallbackClassString;
/**
* `class-string`
*
* `class-string` is a refinement of `string`, so a `@return class-string`
* value always satisfies a native `string` parameter — analyzers that do not
* model it still fall back to `string`. Analyzers that enforce the refinement
* additionally reject a literal that is not a known class name.
*
* References:
* - PHPStan TypeNodeResolver `class-string` resolves to ClassStringType
*/
/**
* @return class-string
*/
function returnsClassString() // T: class-string
{
return \stdClass::class; // V
}
function acceptsString(string $value): void
{
}
/**
* @param class-string $value
*/
function acceptsClassString($value): void // T: class-string
{
}
// A `class-string` value always satisfies a native `string` parameter.
acceptsString(returnsClassString()); // V
// A real class name satisfies the refined parameter.
acceptsClassString(\stdClass::class); // V
// A non-class literal string: enforcing analyzers reject it, others fall back
// to `string` and accept it.
acceptsClassString('not a class name'); // E?: non-class-string should be rejected where class-string is required