`Collection<contravariant Dog>` (call-site contravariance)

Group: Advanced PHPDoc types · Category: ecosystem · File: phpdoc_advanced_phpstan_call_site_contravariant.php

A PHPStan call-site variance spelling. Attaching contravariant to a type argument lets a function accept Collection<Animal> (or Collection<mixed>) where Collection<Dog> is written. Writes of Dog stay valid; reads are mixed, because the item type is not bounded from above. Declaration-site @template-contravariant is generics_template_contravariant. References: - PHPStan phpdoc-types: Generics (Collection<contravariant Type>) - PHPStan "A guide to call-site generic variance"

Analyzer results

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	Unrecognized	phpdoc_advanced_phpstan_call_site_contravariant.php:102: Saw possibly unextractable annotation for a fragment of comment '* @param Collection<contravariant Dog> $collection': after Collection, did not see an element name (will guess based on comment order) [PhanUnextractableAnnotationElementName] phpdoc_advanced_phpstan_call_site_contravariant.php:102: Saw a token Phan may have failed to parse after '* @param Collection<contravariant Dog> $collection': after Collection, saw '<' [PhanUnextractableAnnotationSuffix] phpdoc_advanced_phpstan_call_site_contravariant.php:109: Saw possibly unextractable annotation for a fragment of comment '* @param Collection<contravariant Dog> $collection': after Collection, did not see an element name (will guess based on comment order) [PhanUnextractableAnnotationElementName] phpdoc_advanced_phpstan_call_site_contravariant.php:109: Saw a token Phan may have failed to parse after '* @param Collection<contravariant Dog> $collection': after Collection, saw '<' [PhanUnextractableAnnotationSuffix] phpdoc_advanced_phpstan_call_site_contravariant.php:117: Saw possibly unextractable annotation for a fragment of comment '* @param Collection<contravariant Dog> $collection': after Collection, did not see an element name (will guess based on comment order) [PhanUnextractableAnnotationElementName] phpdoc_advanced_phpstan_call_site_contravariant.php:117: Saw a token Phan may have failed to parse after '* @param Collection<contravariant Dog> $collection': after Collection, saw '<' [PhanUnextractableAnnotationSuffix] phpdoc_advanced_phpstan_call_site_contravariant.php:148: Argument 1 ($collection) is animals() of type \Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection\|\Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<\Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> but \Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesInvariant() takes \Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<\Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog> defined at /Users/megurine/repo/php/php-typing-conformance/conformance/tests/phpdoc_advanced_phpstan_call_site_contravariant.php:127 [PhanTypeMismatchArgument] Recognition: spelling not resolved — reported on declaration line(s) 102, 109, 117 Enforcement: 0/2 of the expected violations reported — incidental, since the spelling was not resolved
phpstan	2.2.15PHPStan - PHP Static Analysis Tool 2.2.15	Enforced reported Lv.5+	phpdoc_advanced_phpstan_call_site_contravariant.php:121: Parameter #1 $dog of function Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesDog expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog, mixed given. [reported-from-level=9] phpdoc_advanced_phpstan_call_site_contravariant.php:142: Parameter #1 $collection of function Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<contravariant Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Cat> given. [reported-from-level=5] phpdoc_advanced_phpstan_call_site_contravariant.php:148: Parameter #1 $collection of function Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesInvariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> given. [reported-from-level=5] With strict-rules phpdoc_advanced_phpstan_call_site_contravariant.php:121: Parameter #1 $dog of function Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesDog expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog, mixed given. phpdoc_advanced_phpstan_call_site_contravariant.php:142: Parameter #1 $collection of function Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<contravariant Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Cat> given. phpdoc_advanced_phpstan_call_site_contravariant.php:148: Parameter #1 $collection of function Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesInvariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> given. Recognition: spelling resolved Enforcement: 2/2 of the expected violations reported
psalm	6.18.0Psalm 6.18.0@536dd6236b39a5115385b0307b42d6d1ad431a02 next: 7.0.0-beta22	Partly enforced (1/2)	phpdoc_advanced_phpstan_call_site_contravariant.php:140: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but parent type Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> provided [ArgumentTypeCoercion] phpdoc_advanced_phpstan_call_site_contravariant.php:141: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but parent type Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<mixed> provided [MixedArgumentTypeCoercion] phpdoc_advanced_phpstan_call_site_contravariant.php:142: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Cat> provided [InvalidArgument] phpdoc_advanced_phpstan_call_site_contravariant.php:143: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\writeContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but parent type Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> provided [ArgumentTypeCoercion] phpdoc_advanced_phpstan_call_site_contravariant.php:148: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesInvariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but parent type Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> provided [ArgumentTypeCoercion] Recognition: spelling resolved Enforcement: 1/2 of the expected violations reported Expectation diff Line 140: Expected valid value to be accepted, got ["Argument 1 of Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\takesContravariant expects Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Dog>, but parent type Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Animal> provided [ArgumentTypeCoercion]"] Line 141: Expected valid value to be accepted, got ["Argument 1 of Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\takesContravariant expects Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Dog>, but parent type Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<mixed> provided [MixedArgumentTypeCoercion]"] Line 143: Expected valid value to be accepted, got ["Argument 1 of Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\writeContravariant expects Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Dog>, but parent type Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Animal> provided [ArgumentTypeCoercion]"] Notes: Ignores the `contravariant` keyword and treats the parameter as invariant Collection<Dog>. Collection<Animal> and Collection<mixed> are rejected on the valid calls (`ArgumentTypeCoercion`); Cat is rejected for the invariant reason, not because it is not a supertype under a projection.
mago	1.50.0mago 1.50.0	Enforced	phpdoc_advanced_phpstan_call_site_contravariant.php:121: Invalid argument type for argument #1 of `Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesDog`: expected `Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog`, but found `mixed`. [mixed-argument] phpdoc_advanced_phpstan_call_site_contravariant.php:142: Invalid argument type for argument #1 of `Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant`: expected `Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>`, but found `Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Cat>`. [invalid-argument] phpdoc_advanced_phpstan_call_site_contravariant.php:148: Argument type mismatch for argument #1 of `Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesInvariant`: expected `Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>`, but provided type `Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal>` is less specific. [less-specific-argument] Recognition: spelling resolved Enforcement: 2/2 of the expected violations reported
mir	0.78.0mir 0.78.0	Unrecognized	phpdoc_advanced_phpstan_call_site_contravariant.php:104: UndefinedDocblockClass: Docblock type 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant Dog' does not exist [MIR1505] phpdoc_advanced_phpstan_call_site_contravariant.php:111: UndefinedDocblockClass: Docblock type 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant Dog' does not exist [MIR1505] phpdoc_advanced_phpstan_call_site_contravariant.php:119: UndefinedDocblockClass: Docblock type 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant Dog' does not exist [MIR1505] phpdoc_advanced_phpstan_call_site_contravariant.php:139: InvalidArgument: Argument $collection of takesContravariant() expects 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant Dog>', got 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>' [MIR0201] phpdoc_advanced_phpstan_call_site_contravariant.php:140: InvalidArgument: Argument $collection of takesContravariant() expects 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant Dog>', got 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal>' [MIR0201] phpdoc_advanced_phpstan_call_site_contravariant.php:142: InvalidArgument: Argument $collection of takesContravariant() expects 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant Dog>', got 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Cat>' [MIR0201] phpdoc_advanced_phpstan_call_site_contravariant.php:143: InvalidArgument: Argument $collection of writeContravariant() expects 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant Dog>', got 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal>' [MIR0201] phpdoc_advanced_phpstan_call_site_contravariant.php:144: InvalidArgument: Argument $collection of readContravariant() expects 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant Dog>', got 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>' [MIR0201] phpdoc_advanced_phpstan_call_site_contravariant.php:148: InvalidArgument: Argument $collection of takesInvariant() expects 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>', got 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal>' [MIR0201] Recognition: spelling not resolved — reported on declaration line(s) 104, 111, 119 Enforcement: 1/2 of the expected violations reported — incidental, since the spelling was not resolved Expectation diff Line 139: Expected valid value to be accepted, got ["InvalidArgument: Argument $collection of takesContravariant() expects 'Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\contravariant Dog>', got 'Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Dog>' [MIR0201]"] Line 140: Expected valid value to be accepted, got ["InvalidArgument: Argument $collection of takesContravariant() expects 'Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\contravariant Dog>', got 'Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Animal>' [MIR0201]"] Line 143: Expected valid value to be accepted, got ["InvalidArgument: Argument $collection of writeContravariant() expects 'Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\contravariant Dog>', got 'Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Animal>' [MIR0201]"] Line 144: Expected valid value to be accepted, got ["InvalidArgument: Argument $collection of readContravariant() expects 'Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\contravariant Dog>', got 'Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Dog>' [MIR0201]"] Notes: Reads `contravariant Dog` as a single class name (with the space). Collection<Dog> itself fails to match Collection<contravariant Dog>.
phpantom	0.10.0phpantom_lsp 0.10.0	Partly enforced (1/2)	phpdoc_advanced_phpstan_call_site_contravariant.php:142: Argument 1 ($collection) expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, got Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Cat> [type_mismatch_argument] Recognition: spelling resolved Enforcement: 1/2 of the expected violations reported Notes: Rejects Collection<Cat> (which invariant Collection<Dog> also does) but accepts Collection<Animal> and Collection<mixed>, and does not treat get() as mixed. Subtyping in the contravariant direction without the read restriction.
intelephense	1.18.5intelephense 1.18.5	Unrecognized	phpdoc_advanced_phpstan_call_site_contravariant.php:102: PHPDoc undefined type 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant'. [P1133] phpdoc_advanced_phpstan_call_site_contravariant.php:109: PHPDoc undefined type 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant'. [P1133] phpdoc_advanced_phpstan_call_site_contravariant.php:117: PHPDoc undefined type 'Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\contravariant'. [P1133] Recognition: spelling not resolved — reported on declaration line(s) 102, 109, 117 Enforcement: 0/2 of the expected violations reported — incidental, since the spelling was not resolved Notes: Reports an undefined type `contravariant` and does not apply call-site contravariance.
phpactor	2026.06.23.0Phpactor 2026.06.23.0	Not enforced	No diagnostics reported. Recognition: spelling resolved Enforcement: 0/2 of the expected violations reported
phpy	1.0.19274phpy 1.0.19274	Not enforced	No diagnostics reported. Recognition: spelling resolved Enforcement: 0/2 of the expected violations reported
qodana	262.9437.196Qodana 262.9437.196	Not enforced	No diagnostics reported. Recognition: spelling resolved Enforcement: 0/2 of the expected violations reported Notes: Silent on Collection<contravariant Dog>: no undefined-type complaint on `contravariant`, and get() is not treated as mixed.
noverify	0.5.5NoVerify, version 0.5.5: built on: 2025.04.22 14:36:46 OS: r-kuchinskas arm64 Commit: 4774b82f8adc53fbef38f95e97af4b953b4d1529	Unrecognized ⚠ 3 false positives	phpdoc_advanced_phpstan_call_site_contravariant.php:43: param $item miss matched with phpdoc type <<T>> [funcParamTypeMissMatch] phpdoc_advanced_phpstan_call_site_contravariant.php:104: param $collection miss matched with phpdoc type <<Collection<contravariant Dog>>> [funcParamTypeMissMatch] phpdoc_advanced_phpstan_call_site_contravariant.php:111: param $collection miss matched with phpdoc type <<Collection<contravariant Dog>>> [funcParamTypeMissMatch] phpdoc_advanced_phpstan_call_site_contravariant.php:119: param $collection miss matched with phpdoc type <<Collection<contravariant Dog>>> [funcParamTypeMissMatch] phpdoc_advanced_phpstan_call_site_contravariant.php:127: param $collection miss matched with phpdoc type <<Collection<Dog>>> [funcParamTypeMissMatch] phpdoc_advanced_phpstan_call_site_contravariant.php:134: param $collection miss matched with phpdoc type <<Collection<Dog>>> [funcParamTypeMissMatch] Recognition: spelling not resolved — reported on declaration line(s) 104, 111, 119 Enforcement: 0/2 of the expected violations reported — incidental, since the spelling was not resolved False positives: line(s) 43, 127, 134 Expectation diff Line 43: Unexpected errors ["param $item miss matched with phpdoc type <<T>> [funcParamTypeMissMatch]"] Line 127: Unexpected errors ["param $collection miss matched with phpdoc type <<Collection<Dog>>> [funcParamTypeMissMatch]"] Line 134: Unexpected errors ["param $collection miss matched with phpdoc type <<Collection<Dog>>> [funcParamTypeMissMatch]"]
steins	0.1.8steins 0.1.8 (2026-09-21 revision 76306a9)	Not enforced	No diagnostics reported. Recognition: spelling resolved Enforcement: 0/2 of the expected violations reported
phpstan-strict	2.2.15PHPStan - PHP Static Analysis Tool 2.2.15	Enforced	phpdoc_advanced_phpstan_call_site_contravariant.php:121: Parameter #1 $dog of function Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesDog expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog, mixed given. phpdoc_advanced_phpstan_call_site_contravariant.php:142: Parameter #1 $collection of function Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<contravariant Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Cat> given. phpdoc_advanced_phpstan_call_site_contravariant.php:148: Parameter #1 $collection of function Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesInvariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> given. Recognition: spelling resolved Enforcement: 2/2 of the expected violations reported
psalm-next	7.0.0-beta22Psalm 7.0.0-beta22@de27e5724ee5997a1e3baee4d394ca6f4e46eba0	Partly enforced (1/2)	phpdoc_advanced_phpstan_call_site_contravariant.php:140: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but parent type Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> provided [ArgumentTypeCoercion] phpdoc_advanced_phpstan_call_site_contravariant.php:141: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but parent type Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<mixed> provided [MixedArgumentTypeCoercion] phpdoc_advanced_phpstan_call_site_contravariant.php:142: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Cat> provided [InvalidArgument] phpdoc_advanced_phpstan_call_site_contravariant.php:143: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\writeContravariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but parent type Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> provided [ArgumentTypeCoercion] phpdoc_advanced_phpstan_call_site_contravariant.php:148: Argument 1 of Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\takesInvariant expects Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Dog>, but parent type Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Collection<Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant\Animal> provided [ArgumentTypeCoercion] Recognition: spelling resolved Enforcement: 1/2 of the expected violations reported Expectation diff Line 140: Expected valid value to be accepted, got ["Argument 1 of Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\takesContravariant expects Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Dog>, but parent type Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Animal> provided [ArgumentTypeCoercion]"] Line 141: Expected valid value to be accepted, got ["Argument 1 of Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\takesContravariant expects Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Dog>, but parent type Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<mixed> provided [MixedArgumentTypeCoercion]"] Line 143: Expected valid value to be accepted, got ["Argument 1 of Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\writeContravariant expects Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Dog>, but parent type Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Collection<Conformance\\Tests\\PhpdocAdvancedPhpstanCallSiteContravariant\\Animal> provided [ArgumentTypeCoercion]"] Notes: Ignores the `contravariant` keyword and treats the parameter as invariant Collection<Dog>. Collection<Animal> and Collection<mixed> are rejected on the valid calls (`ArgumentTypeCoercion`); Cat is rejected for the invariant reason, not because it is not a supertype under a projection.

Source

<?php

declare(strict_types=1);

namespace Conformance\Tests\PhpdocAdvancedPhpstanCallSiteContravariant;

/**
 * `Collection<contravariant Dog>` (call-site contravariance)
 *
 * A PHPStan call-site variance spelling. Attaching `contravariant` to a type
 * argument lets a function accept `Collection<Animal>` (or `Collection<mixed>`)
 * where `Collection<Dog>` is written. Writes of `Dog` stay valid; reads are
 * `mixed`, because the item type is not bounded from above.
 *
 * Declaration-site `@template-contravariant` is `generics_template_contravariant`.
 *
 * References:
 * - PHPStan phpdoc-types: Generics (`Collection<contravariant Type>`)
 * - PHPStan "A guide to call-site generic variance"
 */

class Animal
{
}

class Cat extends Animal
{
}

class Dog extends Animal
{
}

/**
 * @template T
 */
final class Collection
{
    /**
     * @param T $item
     */
    public function __construct(
        public mixed $item,
    ) {
    }

    /**
     * @param T $item
     */
    public function add($item): void
    {
        $this->item = $item;
    }

    /**
     * @return T
     */
    public function get(): mixed
    {
        return $this->item;
    }
}

/**
 * @return Collection<Dog>
 */
function dogs(): Collection
{
    return new Collection(new Dog());
}

/**
 * @return Collection<Animal>
 */
function animals(): Collection
{
    return new Collection(new Animal());
}

/**
 * @return Collection<Cat>
 */
function cats(): Collection
{
    return new Collection(new Cat());
}

/**
 * @param mixed $item
 * @return Collection<mixed>
 */
function mixeds(mixed $item = null): Collection
{
    return new Collection($item);
}

function takesDog(Dog $dog): void
{
}

/**
 * @param Collection<contravariant Dog> $collection
 */
function takesContravariant(Collection $collection): void // T: Collection<contravariant Dog>
{
}

/**
 * @param Collection<contravariant Dog> $collection
 */
function writeContravariant(Collection $collection): void // T: Collection<contravariant Dog>
{
    $collection->add(new Dog()); // V: writes of Dog are allowed
}

/**
 * @param Collection<contravariant Dog> $collection
 */
function readContravariant(Collection $collection): void // T: Collection<contravariant Dog>
{
    takesDog($collection->get()); // E?: get() on a contravariant projection is mixed
}

/**
 * @param Collection<Dog> $collection
 */
function takesInvariant(Collection $collection): void
{
}

/**
 * @param Collection<Dog> $collection
 */
function readInvariant(Collection $collection): void
{
    takesDog($collection->get()); // V: get() on Collection<Dog> is Dog
}

takesContravariant(dogs()); // V
takesContravariant(animals()); // V: Collection<Animal> satisfies Collection<contravariant Dog>
takesContravariant(mixeds()); // V: Collection<mixed> too
takesContravariant(cats()); // E?: Cat is not a supertype of Dog
writeContravariant(animals()); // V
readContravariant(dogs()); // V
readInvariant(dogs()); // V

// Contrast: without the keyword, Collection is invariant.
takesInvariant(animals()); // E?[noise]: Collection<Animal> is not Collection<Dog>

Collection<contravariant Dog> (call-site contravariance)

Analyzer results

Source

`Collection<contravariant Dog>` (call-site contravariance)