Callable signature compatibility in PHPDoc

Group: Callables · Category: language · File: callables_docblock_signature.php

References: - PHPStan callable type syntax - Psalm callable type syntax

Analyzer results

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	Pass	callables_docblock_signature.php:27: Argument 1 ($callback) is (fn) of type Closure(string):string but \Conformance\Tests\CallablesDocblockSignature\takesIntToStringCallable() takes callable(int):string defined at /Users/megurine/repo/php/php-typing-conformance/conformance/tests/callables_docblock_signature.php:18 (expected type to be the same or a subtype, but saw a supertype instead) [PhanTypeMismatchArgumentSuperType]
phpstan	2.3.1PHPStan - PHP Static Analysis Tool 2.3.1	Pass reported Lv.5+	callables_docblock_signature.php:27: Parameter #1 $callback of function Conformance\Tests\CallablesDocblockSignature\takesIntToStringCallable expects callable(int): string, Closure(string): string given. [reported-from-level=5] With strict-rules callables_docblock_signature.php:27: Parameter #1 $callback of function Conformance\Tests\CallablesDocblockSignature\takesIntToStringCallable expects callable(int): string, Closure(string): string given.
psalm	6.20.0Psalm 6.20.0@804f03c0c183d149fcd4b8c7c0c9b3fbf836d34c next: 7.0.0-rc2	Pass	callables_docblock_signature.php:27: Argument 1 of Conformance\Tests\CallablesDocblockSignature\takesIntToStringCallable expects callable(int):string, but pure-Closure(string):string provided [InvalidScalarArgument]
mago	1.57.0mago 1.57.0	Pass	callables_docblock_signature.php:27: Invalid argument type for argument #1 of `Conformance\Tests\CallablesDocblockSignature\takesIntToStringCallable`: expected `(callable(int): string)`, but found `(closure(string): string)`. [invalid-argument]
mir	0.87.0mir 0.87.0	Pass	callables_docblock_signature.php:27: InvalidArgument: Argument $callback of takesIntToStringCallable() expects 'callable whose parameter #1 accepts int', got 'callable whose parameter #1 only accepts string' [MIR0201]
phpantom	0.11.1phpantom_lsp 0.11.1	Pass	callables_docblock_signature.php:27: Argument 1 ($callback) expects callable(int): string, got Closure(string): string (parameter 1 accepts string, but is passed int) [type_mismatch_argument]
intelephense	1.18.5intelephense 1.18.5	Fail	No diagnostics reported. Expectation diff Line 27: Expected 1 error(s)
phpactor	2026.10.07.0Phpactor 2026.10.07.0	Fail	No diagnostics reported. Expectation diff Line 27: Expected 1 error(s)
phpy	1.0.19409phpy 1.0.19409	Fail	No diagnostics reported. Expectation diff Line 27: Expected 1 error(s)
qodana	262.10968.76PhpStorm 262.10968.76	Fail	No diagnostics reported. Expectation diff Line 27: 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	Fail	No diagnostics reported. Expectation diff Line 27: Expected 1 error(s)
steins	0.1.8steins 0.1.8 (2026-09-21 revision 76306a9)	Pass	callables_docblock_signature.php:27: callable argument to takesIntToStringCallable() violates declared @param callable(int): string $callback — parameter #1 type is incompatible (callable parameter contravariance) [phpdoc.param-mismatch]
phpstan-strict	2.3.1PHPStan - PHP Static Analysis Tool 2.3.1	Pass	callables_docblock_signature.php:27: Parameter #1 $callback of function Conformance\Tests\CallablesDocblockSignature\takesIntToStringCallable expects callable(int): string, Closure(string): string given.
psalm-next	7.0.0-rc2Psalm 7.0.0-rc2@20339e3fe5b8d03bcd8061030eb2a83ad50e5783	Pass	callables_docblock_signature.php:27: Argument 1 of Conformance\Tests\CallablesDocblockSignature\takesIntToStringCallable expects callable[impure](int):string, but Closure[pure](string):string provided [InvalidScalarArgument]

Source

<?php

declare(strict_types=1);

namespace Conformance\Tests\CallablesDocblockSignature;

/**
 * Callable signature compatibility in PHPDoc.
 *
 * References:
 * - PHPStan callable type syntax
 * - Psalm callable type syntax
 */

/**
 * @param callable(int): string $callback
 */
function takesIntToStringCallable(callable $callback): void
{
}

takesIntToStringCallable(
    static fn (int $value): string => (string) $value,
);

takesIntToStringCallable(
    static fn (string $value): string => $value, // E: callable parameter type is incompatible
);