Fix #11310: False Positive on Match Arm Comparison with Incremented Bounded Integer

[phpstan-bot]

Summary

When using $i++ (post-increment) as a match expression subject, PHPStan incorrectly used the post-incremented type for arm comparisons. For example, with int<0, max> parameter type, match($i++) would compare arms against int<1, max> instead of int<0, max>, causing false "always false" match arm comparison errors.

Changes

• Modified src/Analyser/NodeScopeResolver.php to capture the condition's native type ($condNativeType) before processing the expression, and pass both the PHPDoc type and native type to enterMatch()
• Modified src/Analyser/MutatingScope.php to accept optional $condType and $condNativeType parameters in enterMatch(), using them instead of re-evaluating the condition on the already-updated scope

Root cause

In NodeScopeResolver, the match expression condition was processed in two stages:

1. $condType = $scope->getType($expr->cond) — captures the type before processing
2. $this->processExprNode(...) — processes the condition, updating the scope (e.g., incrementing $i)
3. $scope->enterMatch($expr) — called on the updated scope

Inside enterMatch(), the condition type was re-evaluated via $this->getType($cond) on the already-modified scope. For $i++, this meant the scope already reflected $i as int<1, max>, so the match subject type became int<1, max> instead of the correct int<0, max>.

The fix passes the pre-computed types (captured before processing) directly to enterMatch(), ensuring the match subject uses the correct type regardless of side effects in the condition expression.

Test

Added tests/PHPStan/Rules/Comparison/data/bug-11310.php with three cases:

• $i++ (post-increment): no false positive — match subject uses original value
• $i-- (post-decrement): no false positive — match subject uses original value
• ++$i (pre-increment): correctly reports always-false comparison with int<1, max> vs 0

Fixes phpstan/phpstan#11310