@template-contravariant T may accept Consumer<Animal> where
Consumer<Dog> is required, because anything that can handle every animal
can handle a dog. Without variance the substitution is rejected.
This case checks the *contravariant* direction: a parent consumer used where
a child consumer is required should be accepted when variance is modeled.
The spelling is not universal: PHPStan reserves @template-contravariant
alongside @template-covariant, while Psalm's documentation only ever names
the covariant one. A tool that does not know the tag does not merely lose the
variance — it loses the template parameter, and then says the class takes
none.
References:
- PHPStan phpdocs-basics: @template, @template-covariant, @template-contravariant
- Psalm templated_annotations.md: template variance| Analyzer | Version | Result | Diagnostics |
|---|---|---|---|
| phan | 6.0.7Phan 6.0.7 php-ast version 1.1.3 PHP version used to run Phan: 8.5.9 | Fail | generics_template_contravariant.php:62: Missing template parameter for type T on constructor for generic class \Conformance\Tests\GenericsTemplateContravariant\Consumer defined at /Users/megurine/repo/php/php-typing-conformance/conformance/tests/generics_template_contravariant.php:40 [PhanGenericConstructorTypes] generics_template_contravariant.php:66: Argument 1 ($consumer) is animalConsumer() of type \Conformance\Tests\GenericsTemplateContravariant\Consumer|\Conformance\Tests\GenericsTemplateContravariant\Consumer<\Conformance\Tests\GenericsTemplateContravariant\Animal> but \Conformance\Tests\GenericsTemplateContravariant\takesDogConsumer() takes \Conformance\Tests\GenericsTemplateContravariant\Consumer<\Conformance\Tests\GenericsTemplateContravariant\Dog> defined at /Users/megurine/repo/php/php-typing-conformance/conformance/tests/generics_template_contravariant.php:53 [PhanTypeMismatchArgument] Expectation diffLine 62: Unexpected errors ["Missing template parameter for type T on constructor for generic class \\Conformance\\Tests\\GenericsTemplateContravariant\\Consumer defined at /Users/megurine/repo/php/php-typing-conformance/conformance/tests/generics_template_contravariant.php:40 [PhanGenericConstructorTypes]"] Line 66: Unexpected errors ["Argument 1 ($consumer) is animalConsumer() of type \\Conformance\\Tests\\GenericsTemplateContravariant\\Consumer|\\Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<\\Conformance\\Tests\\GenericsTemplateContravariant\\Animal> but \\Conformance\\Tests\\GenericsTemplateContravariant\\takesDogConsumer() takes \\Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<\\Conformance\\Tests\\GenericsTemplateContravariant\\Dog> defined at /Users/megurine/repo/php/php-typing-conformance/conformance/tests/generics_template_contravariant.php:53 [PhanTypeMismatchArgument]"] |
| phpstan | 2.2.8PHPStan - PHP Static Analysis Tool 2.2.8 | Pass | No diagnostics reported. |
| psalm | 6.16.1Psalm 6.16.1@f1f5de594dc76faf8784e02d3dc4716c91c6f6ac next: 7.0.0-beta19 |
Fail (pzoom≠) | generics_template_contravariant.php:43: Docblock-defined class, interface or enum named Conformance\Tests\GenericsTemplateContravariant\T does not exist [UndefinedDocblockClass] generics_template_contravariant.php:51: Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Dog> has too many template params, expecting 0 [TooManyTemplateParams] generics_template_contravariant.php:58: Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Animal> has too many template params, expecting 0 [TooManyTemplateParams] generics_template_contravariant.php:66: Argument 1 of Conformance\Tests\GenericsTemplateContravariant\takesDogConsumer expects Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Dog>, but parent type Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Animal> provided [ArgumentTypeCoercion] pzoom (Psalm port)generics_template_contravariant.php:66: Argument 1 of takesDogConsumer expects Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Dog>, but parent type Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Animal> provided [ArgumentTypeCoercion] Expectation diffLine 43: Unexpected errors ["Docblock-defined class, interface or enum named Conformance\\Tests\\GenericsTemplateContravariant\\T does not exist [UndefinedDocblockClass]"] Line 51: Unexpected errors ["Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<Conformance\\Tests\\GenericsTemplateContravariant\\Dog> has too many template params, expecting 0 [TooManyTemplateParams]"] Line 58: Unexpected errors ["Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<Conformance\\Tests\\GenericsTemplateContravariant\\Animal> has too many template params, expecting 0 [TooManyTemplateParams]"] Line 66: Unexpected errors ["Argument 1 of Conformance\\Tests\\GenericsTemplateContravariant\\takesDogConsumer expects Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<Conformance\\Tests\\GenericsTemplateContravariant\\Dog>, but parent type Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<Conformance\\Tests\\GenericsTemplateContravariant\\Animal> provided [ArgumentTypeCoercion]"] |
| mago | 1.46.0mago 1.46.0 | Pass | No diagnostics reported. |
| mir | 0.70.1mir 0.70.1 | Pass | No diagnostics reported. |
| phpantom | 0.9.0phpantom_lsp 0.9.0 | Pass | No diagnostics reported. |
| intelephense | 1.18.5intelephense 1.18.5 | Fail | generics_template_contravariant.php:43: PHPDoc undefined type 'Conformance\Tests\GenericsTemplateContravariant\T'. [P1133] Expectation diffLine 43: Unexpected errors ["PHPDoc undefined type 'Conformance\\Tests\\GenericsTemplateContravariant\\T'. [P1133]"] |
| phpy | 0.2.0phpy 0.2.0 | Pass | No diagnostics reported. |
| qodana | 262.8665.325Qodana 262.8665.325 | Pass | 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 | Fail | generics_template_contravariant.php:53: param $consumer miss matched with phpdoc type <<Consumer<Dog>>> [funcParamTypeMissMatch] Expectation diffLine 53: Unexpected errors ["param $consumer miss matched with phpdoc type <<Consumer<Dog>>> [funcParamTypeMissMatch]"] |
| steins | 0.1.5steins 0.1.5 (2026-08-12 revision 39b4cc1) | Pass | No diagnostics reported. |
| phpstan-strict | 2.2.8PHPStan - PHP Static Analysis Tool 2.2.8 | Pass | No diagnostics reported. |
| psalm-next | 7.0.0-beta19Psalm 7.0.0-beta19@7e751c06a756fa64dc4c759c09fe4a173afcb433 | Fail | generics_template_contravariant.php:43: Docblock-defined class, interface or enum named Conformance\Tests\GenericsTemplateContravariant\T does not exist [UndefinedDocblockClass] generics_template_contravariant.php:51: Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Dog> has too many template params, expecting 0 [TooManyTemplateParams] generics_template_contravariant.php:58: Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Animal> has too many template params, expecting 0 [TooManyTemplateParams] generics_template_contravariant.php:66: Argument 1 of Conformance\Tests\GenericsTemplateContravariant\takesDogConsumer expects Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Dog>, but parent type Conformance\Tests\GenericsTemplateContravariant\Consumer<Conformance\Tests\GenericsTemplateContravariant\Animal> provided [ArgumentTypeCoercion] Expectation diffLine 43: Unexpected errors ["Docblock-defined class, interface or enum named Conformance\\Tests\\GenericsTemplateContravariant\\T does not exist [UndefinedDocblockClass]"] Line 51: Unexpected errors ["Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<Conformance\\Tests\\GenericsTemplateContravariant\\Dog> has too many template params, expecting 0 [TooManyTemplateParams]"] Line 58: Unexpected errors ["Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<Conformance\\Tests\\GenericsTemplateContravariant\\Animal> has too many template params, expecting 0 [TooManyTemplateParams]"] Line 66: Unexpected errors ["Argument 1 of Conformance\\Tests\\GenericsTemplateContravariant\\takesDogConsumer expects Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<Conformance\\Tests\\GenericsTemplateContravariant\\Dog>, but parent type Conformance\\Tests\\GenericsTemplateContravariant\\Consumer<Conformance\\Tests\\GenericsTemplateContravariant\\Animal> provided [ArgumentTypeCoercion]"] |
<?php
declare(strict_types=1);
namespace Conformance\Tests\GenericsTemplateContravariant;
/**
* Template variance: contravariant type parameters
*
* The counterpart of the covariant case. A consumer annotated
* `@template-contravariant T` may accept `Consumer<Animal>` where
* `Consumer<Dog>` is required, because anything that can handle every animal
* can handle a dog. Without variance the substitution is rejected.
*
* This case checks the *contravariant* direction: a parent consumer used where
* a child consumer is required should be accepted when variance is modeled.
*
* The spelling is not universal: PHPStan reserves `@template-contravariant`
* alongside `@template-covariant`, while Psalm's documentation only ever names
* the covariant one. A tool that does not know the tag does not merely lose the
* variance — it loses the template parameter, and then says the class takes
* none.
*
* References:
* - PHPStan phpdocs-basics: @template, @template-covariant, @template-contravariant
* - Psalm templated_annotations.md: template variance
*/
class Animal
{
}
class Dog extends Animal
{
}
/**
* @template-contravariant T
*/
final class Consumer
{
/**
* @param T $value
*/
public function consume($value): void
{
}
}
/**
* @param Consumer<Dog> $consumer
*/
function takesDogConsumer(Consumer $consumer): void
{
}
/**
* @return Consumer<Animal>
*/
function animalConsumer(): Consumer
{
return new Consumer();
}
// Contravariance: a consumer of any Animal can stand in for a consumer of Dog.
takesDogConsumer(animalConsumer());