object types with optional properties don't get their inferred type changed after isset() check

[ShadauxCat]

<?php
/**
 * @param object{
 *    bar?: object{
 *      baz?: string
 *   }
 * }|null $foo
 * @return void
 */
function testSparce($foo)
{
    // This should change the inferred type, no?
    if (isset($foo->bar->baz))
    {
        testConcrete($foo);
    }
}
/**
 * @param object{
 *    bar: object{
 *      baz: string
 *   }
 * } $foo
 * @return void
 */
function testConcrete($foo)
{
    echo "" . $foo->bar->baz;
}

After that isset() check, I would expect psalm to change its interpretation of the type of $foo to know that all the optional parameters are set. The call to testConcrete($foo) should work here. Instead, it flags this error:

ERROR: ArgumentTypeCoercion - 15:22 - Argument 1 of testConcrete expects object{bar:object{baz:string}}, parent type object{bar?:object{baz?:string}} provided

https://psalm.dev/r/9560e1b060

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/9560e1b060

<?php
/**
 * @param object{
 *    bar?: object{
 *      baz?: string
 *   }
 * }|null $foo
 * @return void
 */
function testSparce($foo)
{
    // This should change the inferred type, no?
	if (isset($foo->bar->baz))
    {
        testConcrete($foo);
	}
}
/**
 * @param object{
 *    bar: object{
 *      baz: string
 *   }
 * } $foo
 * @return void
 */
function testConcrete($foo)
{
	echo "" . $foo->bar->baz;
}

Psalm output (using commit c912b6c):

ERROR: ArgumentTypeCoercion - 15:22 - Argument 1 of testConcrete expects object{bar:object{baz:string}}, parent type object{bar?:object{baz?:string}} provided

[M1ke]

I think this is the same issue I just reproduced here:

https://psalm.dev/r/c90854d4fc

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/c90854d4fc

<?php

/**
 * @param array{a?: array{foo: bool, bar: bool}} $arr
 */
function foo(array $arr):void {
   $a = $arr['a'] ?? [];
    if ($a){
        bar($a);
    }
}

/**
 * @param array{foo: bool, bar: bool} $arr
 */
function bar(array $arr):void{
}

Psalm output (using commit f6369dc):

ERROR: ArgumentTypeCoercion - 9:13 - Argument 1 of bar expects array{bar: bool, foo: bool}, parent type array{bar?: bool, foo?: bool} provided

INFO: UnusedParam - 16:20 - Param $arr is never referenced in this method

[M1ke]

I think it's because the type-checker converts our optional array into an array where each key is optional - thus even when the original key is determined to exist, the types of it's content have changed to an array of optional keys.

I presume the fix therefore is to resolve that an array with non-optional keys that is a type of an optional key in a parent array doesn't have that behaviour implied.

[orklah]

This issue is very related to #2206

@M1ke your case is different though. Psalm is not fine enough to understand that you basically have array{foo: bool, bar: bool}|array<never, never>. It simplifies that into array{foo?: bool, bar?: bool} which means it transforms either foo AND bar are defined or we have an empty array into foo and bar can both be possibly_undefined. The second version is not enough to infer anything when we go through if($a)