Union assertions not detecting paradoxes

[danog]

Possibly introduced by #8077: https://psalm.dev/r/49f98e503d

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/49f98e503d

<?php
                    namespace Bar;

                    /**
                     * Asserts that two variables are not the same.
                     *
                     * @template T
                     * @param T      $expected
                     * @param mixed  $actual
                     * @psalm-assert T $actual
                     */
                    function assertNotSame($expected, $actual) : void {}

                    $expected = rand(0, 1) ? 4 : 5;
                    $actual = 6;
                    assertNotSame($expected, $actual);
/** @psalm-trace $actual */;

Psalm output (using commit 4b2935f):

INFO: UnusedParam - 12:44 - Param $expected is never referenced in this method

INFO: UnusedParam - 12:55 - Param $actual is never referenced in this method

INFO: Trace - 17:28 - $actual: 6

[AndrolGenhald]

Shouldn't it assert !T?

Actually, I'm not sure what it should assert... Is this even possible to do correctly? If you have both $expected and $actual as strings then it shouldn't be asserting !T, but if $expected is string and $actual is float you don't want it asserting T either. Did this ever work? Do we actually check for paradoxes with assertion functions (I know we check redundancy, but I'm not sure I've ever seen paradoxes there)?

[danog]

I actually want to assertEqual: https://psalm.dev/r/2438f000d1
I expect it to complain that we expect a 4|5, but have only a 6: we're precisely missing paradox logic here.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/2438f000d1

<?php
                    namespace Bar;

                    /**
                     * Asserts that two variables are not the same.
                     *
                     * @template T
                     * @param T      $expected
                     * @param mixed  $actual
                     * @psalm-assert T $actual
                     */
                    function assertSame($expected, $actual) : void {}

                    $expected = rand(0, 1) ? 4 : 5;
                    $actual = 6;
                    assertSame($expected, $actual);
/** @psalm-trace $actual */;

Psalm output (using commit 4b2935f):

INFO: UnusedParam - 12:41 - Param $expected is never referenced in this method

INFO: UnusedParam - 12:52 - Param $actual is never referenced in this method

INFO: Trace - 17:28 - $actual: 6

[AndrolGenhald]

assert works fine but behaves slightly differently, since it will generally be ignored in production environments. I wasn't aware we actually supported that, but it works for non-unions, so it should probably work for unions too.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/a6dc1e3b9a

<?php

$expected = rand(0, 1) ? 4 : 5;
$actual = 6;
assert($expected === $actual);
/** @psalm-trace $actual */;

Psalm output (using commit 4b2935f):

ERROR: TypeDoesNotContainType - 5:8 - 6 cannot be identical to 4|5

ERROR: TypeDoesNotContainType - 5:1 - Type 4|5 for $expected is never =int(6)

INFO: Trace - 6:28 - $actual: 6

https://psalm.dev/r/97bbacb893

<?php
                    namespace Bar;

                    /**
                     * Asserts that two variables are not the same.
                     *
                     * @template T
                     * @param T      $expected
                     * @param mixed  $actual
                     * @psalm-assert T $actual
                     */
                    function assertSame($expected, $actual) : void {}

                    $expected = 5;
                    $actual = 6;
                    assertSame($expected, $actual);
/** @psalm-trace $actual */;

Psalm output (using commit 4b2935f):

ERROR: TypeDoesNotContainType - 16:21 - Type 6 for $actual is never 5

INFO: Trace - 17:28 - $actual: never

[orklah]

fixed in master :)