Fix phpstan/phpstan#13029: False match.unhandled on array with multiple booleans

[phpstan-bot]

Summary

Fixes a false positive match.unhandled error when using a match expression with an array subject containing multiple booleans and multi-condition arms (comma-separated conditions).

For example, this valid code was incorrectly reported as having an unhandled array{true, bool}:

$x = match([$bool1, $bool2]) {
    [true, false], [true, true] => 1,
    [false, false] => 0,
    [false, true] => -1,
};

Changes

• Modified TypeCombinator::remove() in src/Type/TypeCombinator.php to handle removal of types with multiple finite types
• Added regression test in tests/PHPStan/Rules/Comparison/data/bug-13029.php
• Added test method testBug13029 in tests/PHPStan/Rules/Comparison/MatchExpressionRuleTest.php

Root cause

When a match arm has multiple conditions (e.g., [true, false], [true, true]), PHPStan builds an in_array() expression for type narrowing. The SpecifiedTypes::unionWith() correctly combines the sureNotTypes from each condition into a union type (e.g., array{true, false} | array{true, true} simplifies to array{true, bool}).

However, TypeCombinator::remove() had a restriction at line 93 that only performed finite-type-based removal when the type to remove had exactly 1 finite type (count($finiteTypesToRemove) === 1). The union array{true, bool} has 2 finite types (array{true, true} and array{true, false}), so the removal was silently skipped, leaving the match condition type un-narrowed.

The fix changes the condition to count($finiteTypesToRemove) > 0 and compares against all finite types to remove, not just the first one.

Test

Added a regression test that reproduces the exact scenario from the issue: a match expression with [$bool1, $bool2] as the subject where the first arm uses comma-separated array conditions [true, false], [true, true]. The test expects no errors (empty expected errors array).

Fixes phpstan/phpstan#13029

[VincentLanglet]

Seems fine to me ; but this seems to not be enough for the related issue phpstan/phpstan#10128

[staabm]

since this fix is based on finite types, maybe we can also add a test for int-ranges?

[staabm]

like

• https://phpstan.org/r/ddfde494-adcb-46af-a775-38ce6e8671f3 (int-range)
• https://phpstan.org/r/60373c38-eac1-410a-a1d9-47fd1aaf2f56 (union of int)

[staabm]

love it

[VincentLanglet]

That doesn't solve

$y = match([$int1, $int2]) {
		[0, 0], [1, 1], [2, 2] => 1,
		[0, 1], [1, 2], [2, 0] => 0,
		[0, 2], [1, 0], [2, 1] => -1,
	};

Because of simplification... I hope the bot will find why ^^