array_keys() does not always infer the key type from the given array

[BenMorel]

Bug report

This is similar to #1847, but we're still getting the error with phpstan 0.11.19 and 0.12.5.

Even though the array key type is known, in some situations it is not used to infer the type of array_keys().

Code snippet that reproduces the problem

    /**
     * @param array<string, true> $knownAliases
     */
    function getSQLForJoins(string $fromAlias, array &$knownAliases) : string
    {
        ...
            throw NonUniqueAlias::new($join['joinAlias'], array_keys($knownAliases));

Here the type of array_keys($knownAliases) is inferred as array<int, int|string> instead of array<int, string>.

Sandbox: https://phpstan.org/r/98b7db20-f773-49d9-86d7-014f5d209483
Travis: https://travis-ci.org/doctrine/dbal/jobs/638201455

If you remove lines 45-48 (after the culprit), it suddenly works:

https://phpstan.org/r/586a6826-b4f7-4ea0-8c62-f3fa8a643a1a

Expected output

[OK] No errors

Actual output

 ------ ----------------------------------------------------------------------------------------------------------------------------------------------------------- 
  Line   lib/Doctrine/DBAL/Query/QueryBuilder.php                                                                                                                   
 ------ ----------------------------------------------------------------------------------------------------------------------------------------------------------- 
  1319   Parameter #2 $registeredAliases of static method Doctrine\DBAL\Query\Exception\NonUniqueAlias::new() expects array<string>, array<int, int|string> given.  
 ------ ----------------------------------------------------------------------------------------------------------------------------------------------------------- 

[morozov]

Looks like this is because of $knownAliases[$join['joinAlias']] = true. Although we specify the type of $knownAliases as array<string, true>, given that the type of $join['joinAlias'] is unknown to PHPStan, setting this key on the array makes it array<int|string, true>.

Unless there's a way to specify the type of joinAlias on $join (like array{joinAlias: string} in Psalm), we could use an assertion.

[ondrejmirtes]

PHPStan doesn't know what $join['joinAlias'] alias is, it's mixed for the analysis. So array_keys($knownAliases) are an array of int|string.

You can fix this by introducing some local variables and using inline @var PHPDocs.

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.