false PossiblyUndefinedStringArrayOffset for shape.

[azjezz]

example: https://psalm.dev/r/d3ce80c00a

In this scenario, T ( and therefor $datum ) is known to contain array{foo: string}

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/d3ce80c00a

<?php

/**
 * @template T
 *
 * @param array<array-key, T> $iterable
 * @param (callable(T): bool) $predicate
 *
 * @return list<T>
 */
function filter(array $iterable, callable $predicate): array
{
    return array_values(array_filter(
        $iterable,
        /**
         * @param T $t
         */
        static fn($t): bool => $predicate($t)
    ));
}

$foo = 'CA';

/** @var list<array{foo: string}> $data */
$data = [
    [
        'foo' => 'CA',
    ],
    [
        'foo' => 'CA',
    ],
];

/** @psalm-trace $data */

filter($data, fn (array $datum): bool => /** @psalm-trace $datum */ $datum['foo'] === $foo);

Psalm output (using commit e6e5869):

INFO: PossiblyUndefinedStringArrayOffset - 36:69 - Possibly undefined array offset '"foo"' is risky given expected type 'array-key'. Consider using isset beforehand.

INFO: Trace - 36:69 - $datum: array<array-key, mixed>

INFO: Trace - 36:1 - $data: list<array{foo: string}>

[azjezz]

first reported at: azjezz/psl#226

[weirdan]

It's probably possible to constrain the closure signature if it's defined inside a function call and [edit: this is important] there's no references to it in the enclosing scope, but it's not something that we have at the moment, not for calls to user-defined functions anyway.

[orklah]

This was fixed