array<array-key, mixed> not compatible with array<int|string, mixed> why?

[tomchochola]

why is this marked as error?

is not array-key equal to int|string?

Source code

/**
 * @return array<array-key, mixed>
 */
function returnArrayKeyMixed(): array
{
    return ['key' => 'value', 1];
}

/**
 * @param array<int|string, mixed> $array
 */
function acceptIntStringMixed(array $array): void {}

acceptIntStringMixed(returnArrayKeyMixed());

PHPStan error

Parameter #1 $array expects array<int|string, mixed>, array given.

Versions

"php": "^8.3",
"phpstan/extension-installer": "@stable",
"phpstan/phpstan": "@stable",
"phpstan/phpstan-deprecation-rules": "@stable",
"phpstan/phpstan-mockery": "@stable",
"phpstan/phpstan-phpunit": "@stable",
"phpstan/phpstan-strict-rules": "@stable",
"phpstan/phpstan-symfony": "@stable"

PHPStan config

includes:
  - phar://phpstan.phar/conf/bleedingEdge.neon

parameters:
  level: max
  checkMissingCallableSignature: true
  checkTooWideReturnTypesInProtectedAndPublicMethods: true
  checkUninitializedProperties: true
  reportAlwaysTrueInLastCondition: true
  checkBenevolentUnionTypes: true
  checkImplicitMixed: true
  checkMissingOverrideMethodAttribute: true
  treatPhpDocTypesAsCertain: false
  tipsOfTheDay: false

Valid variation 1

switching array-key to int|string on return and array-key on input passes

/**
 * @return array<int|string, mixed>
 */
function returnIntStringMixed(): array
{
    return ['key' => 'value', 1];
}

/**
 * @param array<array-key, mixed> $array
 */
function acceptArrayKeyMixed(array $array): void {}

acceptArrayKeyMixed(returnIntStringMixed());

Valid variation 2

switching array<array-key, *> to *[] on return passes

/**
 * @return mixed[]
 */
function returnArrayOfMixed(): array
{
    return ['key' => 'value', 1];
}

/**
 * @param array<array-key, mixed> $array
 */
function acceptArrayKeyMixed(array $array): void {}

acceptArrayKeyMixed(returnArrayOfMixed());

[ondrejmirtes]

Yes, it should be interchangeable.

[ondrejmirtes]

Please open a bug report about this.

[tomchochola]

issue opened: #10624