Passing class-string-map to variadic crashes psalm

[AndrolGenhald]

https://psalm.dev/r/93f8d3fbc4

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/93f8d3fbc4

<?php

class A {}

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

/** @var class-string-map<A, A> */
$map = [A::class => new A()];
takesVariadic(...$map);

Psalm encountered an internal error:

/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php: Argument 2 passed to Psalm\Internal\Analyzer\Statements\Expression\Call\ArgumentAnalyzer::verifyType() must be an instance of Psalm\Type\Union, null given, called in /vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php on line 508

[AndrolGenhald]

So the issue is here, and the @var annotation prevents psalm from catching the issue.

I was thinking about adding a @psalm-type Type=array{array?: array-types, int?: int-types, etc} to Union and having getAtomicTypes() return that, which would be beneficial in a lot of other places as well, but it's currently a non-empty-array and it's not possible to have a non-empty object like array when all keys are optional. It looks like object like arrays are supposed to be nonempty when there are required keys, but that's a bit finicky too: https://psalm.dev/r/23869e7fec

Would it be a good idea to add support for non-empty-array{a?: string, b?: string}?

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/23869e7fec

<?php

/**
 * @psalm-suppress UnusedParam
 * @param non-empty-array<string, string> $arg
 */
function test(array $arg): void {}

/** @var array{a?: string, b: string} */
$a = ['b' => 'b'];
test($a); // 'b' is required, $a should be non-empty-array

/** @var array{a: string, b?: string} */
$b = ['a' => 'a'];
test($b); // works

Psalm output (using commit 42d3bce):

ERROR: ArgumentTypeCoercion - 11:6 - Argument 1 of test expects non-empty-array<string, string>, parent type array{a?: string, b: string} provided

[muglug]

I think it might be useful to have an alias of all the possible array types for such situations (all types where the getKey method returns 'array')