@param array<int>|array<string> means "all ints, or all strings" — not
"each element may be int or string". A mixed literal such as [1, 'b', 3]
is therefore out of range: it is neither array<int> nor array<string>.
By contrast array<int|string> would accept the same value.
PHPStan historically accepted the mixed array (issue #8963, open as a
feature request). This records whether each analyzer distinguishes the two
spellings.
Reference: phpstan#8963| 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 | Fail | No diagnostics reported. Expectation diffLine 36: Expected 1 error(s) |
| phpstan | 2.3.1PHPStan - PHP Static Analysis Tool 2.3.1 | Fail | No diagnostics reported. Expectation diffLine 36: Expected 1 error(s) |
| psalm | 6.20.0Psalm 6.20.0@804f03c0c183d149fcd4b8c7c0c9b3fbf836d34c next: 7.0.0-rc2 |
Fail (pzoom≠) | pzoom (Psalm port)regressions_union_of_arrays_vs_array_of_unions.php:36: Argument 1 of takesHomogeneousIntOrStringArray expects array<array-key, int>|array<array-key, string>, but list{1, 'b', 3} provided [InvalidArgument]Expectation diffLine 36: Expected 1 error(s) |
| mago | 1.57.0mago 1.57.0 | Pass | regressions_union_of_arrays_vs_array_of_unions.php:36: Possible argument type mismatch for argument #1 of `Conformance\Tests\RegressionsUnionOfArraysVsArrayOfUnions\takesHomogeneousIntOrStringArray`: expected `array<array-key, int>|array<array-key, string>`, but possibly received `list{int(1), string('b'), int(3)}`. [possibly-invalid-argument] |
| mir | 0.87.0mir 0.87.0 | Pass | regressions_union_of_arrays_vs_array_of_unions.php:36: InvalidArgument: Argument $values of takesHomogeneousIntOrStringArray() expects 'array<int|string, int>|array<int|string, string>', got 'array{0: 1, 1: "b", 2: 3}' [MIR0201] |
| phpantom | 0.11.1phpantom_lsp 0.11.1 | Pass | regressions_union_of_arrays_vs_array_of_unions.php:36: Argument 1 ($values) expects array<int>|array<string>, got array{1, 'b', 3} [type_mismatch_argument] |
| intelephense | 1.18.5intelephense 1.18.5 | Fail | No diagnostics reported. Expectation diffLine 36: Expected 1 error(s) |
| phpactor | 2026.10.07.0Phpactor 2026.10.07.0 | Fail | No diagnostics reported. Expectation diffLine 36: Expected 1 error(s) |
| phpy | 1.0.19409phpy 1.0.19409 | Fail | No diagnostics reported. Expectation diffLine 36: Expected 1 error(s) |
| qodana | 262.10968.76PhpStorm 262.10968.76 | Fail | No diagnostics reported. Expectation diffLine 36: 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 | regressions_union_of_arrays_vs_array_of_unions.php:25: param $values miss matched with phpdoc type <<array<int>|array<string>>> [funcParamTypeMissMatch] Expectation diffLine 36: Expected 1 error(s) |
| steins | 0.1.8steins 0.1.8 (2026-09-21 revision 76306a9) | Pass | regressions_union_of_arrays_vs_array_of_unions.php:36: argument [1, 'b', 3] to takesHomogeneousIntOrStringArray() violates declared @param (array<int> | array<string>) $values — declared contract violation [phpdoc.param-mismatch] |
| phpstan-strict | 2.3.1PHPStan - PHP Static Analysis Tool 2.3.1 | Fail | No diagnostics reported. Expectation diffLine 36: Expected 1 error(s) |
| psalm-next | 7.0.0-rc2Psalm 7.0.0-rc2@20339e3fe5b8d03bcd8061030eb2a83ad50e5783 | Fail | No diagnostics reported. Expectation diffLine 36: Expected 1 error(s) |
<?php
declare(strict_types=1);
namespace Conformance\Tests\RegressionsUnionOfArraysVsArrayOfUnions;
/**
* Union of homogeneous arrays is not an array of unions.
*
* `@param array<int>|array<string>` means "all ints, or all strings" — not
* "each element may be int or string". A mixed literal such as `[1, 'b', 3]`
* is therefore out of range: it is neither `array<int>` nor `array<string>`.
* By contrast `array<int|string>` would accept the same value.
*
* PHPStan historically accepted the mixed array (issue #8963, open as a
* feature request). This records whether each analyzer distinguishes the two
* spellings.
*
* Reference: https://github.com/phpstan/phpstan/issues/8963
*/
/**
* @param array<int>|array<string> $values
*/
function takesHomogeneousIntOrStringArray(array $values): void // E<noverify>: NoVerify cannot evaluate the generic array union and flags the signature itself
{
}
// Pure int list — member of array<int>.
takesHomogeneousIntOrStringArray([1, 2, 3]);
// Pure string list — member of array<string>.
takesHomogeneousIntOrStringArray(['a', 'b', 'c']);
// Mixed elements: neither array<int> nor array<string>.
takesHomogeneousIntOrStringArray([1, 'b', 3]); // E: array<int|string> is not accepted by array<int>|array<string>