Add regression test for bug 10942 (contravariant phpdoc union)

[yt-catpaw]

• Add the reported case to nsrt: tests/PHPStan/Analyser/nsrt/bug-10942.php
• Wire it into AnalyserIntegrationTest::testBug10942
• Verified it passes on current 2.1.x (PHP 8.3.19)

closes phpstan/phpstan#10942

If you ran the focused test, you can mention:
vendor/bin/phpunit --filter testBug10942 tests/PHPStan/Analyser/AnalyserIntegrationTest.php

[ondrejmirtes]

Hey, I don't understand this PR. You're adding a regression test for an issue but the issue isn't fixed. So I'm sorry, but I can't merge this PR in the current state of the code.

[yt-catpaw]

@ondrejmirtes

I added the reporter’s test case intending to fix the issue, but the error didn’t reproduce, so the PR only adds the test. Is that a problem?

I added the reporter’s case to nsrt and it no longer reproduces on current 2.1.x (PHP 8.3.19) — the test passes. I’d still like to keep the test as a regression safeguard so we catch any future breakage.

[ondrejmirtes]

The bug is not fixed. If it was fixed then the playground https://phpstan.org/r/819a30a6-5477-448a-a421-24076f8dcd0f would tell you about it.

The bug is happening only if you enable strict rules. In phpstan-src parlance, it will probably happen only with reportMaybesInMethodSignatures: true.

The best way to reproduce it would be in MethodSignatureRuleTest. But it has to be fixed first.

[yt-catpaw]

Sorry for the confusion — after moving the case into MethodSignatureRuleTest with strict settings, I can reproduce the original “should be contravariant” error. Thanks for pointing me in the right direction. I’ll take a look from here.