Add regression test for phpstan/phpstan#12373

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php

@@ -1414,6 +1414,17 @@ public function testBug14274(): void
 		$this->analyse([__DIR__ . '/data/bug-14274.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testBug12373(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = false;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+
+		$this->analyse([__DIR__ . '/data/bug-12373.php'], []);
+	}
+
 	public function testBug14117(): void
 	{
 		$this->cliArgumentsVariablesRegistered = true;

tests/PHPStan/Rules/Variables/data/bug-12373.php

@@ -0,0 +1,28 @@
+<?php // lint >= 8.0
+
+namespace Bug12373;
+
+function test(): void
+{
+	$foo = [];
+
+	[$always_a, $always_b, $always_c] = [rand(0, 1), rand(0, 1), rand(0, 1)];
+	if (rand(0, 1)) {
+		[$maybe_a, $maybe_b, $maybe_c] = [rand(0, 1), rand(0, 1), rand(0, 1)];
+		$flag = true;
+	} else {
+		$flag = false;
+	}
+
+	if ($flag && $always_a !== $maybe_a) {
+		$foo[] = 'first';
+	}
+
+	if (($always_a && !$always_b) || ($flag && $maybe_a && !$maybe_b)) {
+		$foo[] = 'second';
+	}
+
+	if (($always_a && !$always_c) || ($flag && $maybe_a && !$maybe_c)) {
+		$foo[] = 'third';
+	}
+}