Fix phpstan/phpstan#14446: Incorrect type-narrowing when using strict rules (#5435)

Co-authored-by: VincentLanglet <9052536+VincentLanglet@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Vincent Langlet <vincentlanglet@hotmail.fr>

Author: 3 people

src/Analyser/MutatingScope.php

@@ -3738,7 +3738,7 @@ public function processFinallyScope(self $finallyScope, self $originalFinallySco
 				$finallyScope->nativeExpressionTypes,
 				$originalFinallyScope->nativeExpressionTypes,
 			),
-			$this->conditionalExpressions,
+			$this->intersectConditionalExpressions($finallyScope->conditionalExpressions),
 			$this->inClosureBindScopeClasses,
 			$this->anonymousFunctionReflection,
 			$this->inFirstLevelStatement,
@@ -3883,7 +3883,7 @@ public function processAlwaysIterableForeachScopeWithoutPollute(self $finalScope
 			$this->getNamespace(),
 			$expressionTypes,
 			$nativeTypes,
-			$this->conditionalExpressions,
+			$this->intersectConditionalExpressions($finalScope->conditionalExpressions),
 			$this->inClosureBindScopeClasses,
 			$this->anonymousFunctionReflection,
 			$this->inFirstLevelStatement,

tests/PHPStan/Analyser/Bug14446Test.php

@@ -0,0 +1,36 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Analyser;
+
+use PHPStan\Testing\TypeInferenceTestCase;
+use PHPUnit\Framework\Attributes\DataProvider;
+
+class Bug14446Test extends TypeInferenceTestCase
+{
+
+	public static function dataFileAsserts(): iterable
+	{
+		yield from self::gatherAssertTypes(__DIR__ . '/data/bug-14446.php');
+	}
+
+	/**
+	 * @param mixed ...$args
+	 */
+	#[DataProvider('dataFileAsserts')]
+	public function testFileAsserts(
+		string $assertType,
+		string $file,
+		...$args,
+	): void
+	{
+		$this->assertFileAsserts($assertType, $file, ...$args);
+	}
+
+	public static function getAdditionalConfigFiles(): array
+	{
+		return [
+			__DIR__ . '/bug-14446.neon',
+		];
+	}
+
+}

tests/PHPStan/Analyser/bug-14446.neon

@@ -0,0 +1,2 @@
+parameters:
+	polluteScopeWithAlwaysIterableForeach: false

tests/PHPStan/Analyser/data/bug-14446.php

@@ -0,0 +1,102 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14446;
+
+use function PHPStan\Testing\assertType;
+
+function test(bool $initial): void {
+    $current = $initial;
+
+    while (true) {
+		assertType('bool', $initial);
+        if (!$current) {
+			assertType('bool', $initial);
+            break;
+        }
+
+        $items = [1];
+        foreach ($items as $item) {
+            $current = false;
+        }
+    }
+
+	assertType('bool', $initial);
+	var_dump($initial === true);
+}
+
+function testMaybeIterable(bool $initial): void {
+	$current = $initial;
+
+	while (true) {
+		assertType('bool', $initial);
+		if (!$current) {
+			assertType('bool', $initial);
+			break;
+		}
+
+		$items = rand() > 0 ? [1] : [];
+		foreach ($items as $item) {
+			$current = false;
+		}
+	}
+
+	assertType('bool', $initial);
+	var_dump($initial === true);
+}
+
+function testFinally(bool $initial): void {
+	$current = $initial;
+	try {
+		// nothing
+	} finally {
+		$current = false;
+	}
+	assertType('false', $current);
+	assertType('bool', $initial);
+	if (!$current) {
+		assertType('bool', $initial);
+	}
+}
+
+function testFinallyWithCatch(bool $initial): void {
+	$current = $initial;
+	try {
+		doSomething();
+	} catch (\Exception $e) {
+		// nothing
+	} finally {
+		$current = false;
+	}
+	assertType('false', $current);
+	if (!$current) {
+		assertType('bool', $initial);
+	}
+	assertType('bool', $initial);
+}
+
+function doSomething(): void {}
+
+/**
+ * @param mixed $value
+ */
+function testForeachKeyOverwrite($value): void {
+	if (is_array($value) && $value !== []) {
+		$hasOnlyStringKey = true;
+		foreach (array_keys($value) as $key) {
+			if (is_int($key)) {
+				$hasOnlyStringKey = false;
+				break;
+			}
+		}
+
+		assertType('bool', $hasOnlyStringKey);
+
+		if ($hasOnlyStringKey) {
+			// $key should not be in scope here with polluteScopeWithAlwaysIterableForeach: false
+			// Second foreach should not report "Foreach overwrites $key with its key variable"
+			foreach ($value as $key => $element) {
+				assertType('(int|string)', $key);
+			}
+		}
+	}
+}

tests/PHPStan/Rules/Comparison/StrictComparisonOfDifferentTypesRuleTest.php

@@ -20,6 +20,8 @@ class StrictComparisonOfDifferentTypesRuleTest extends RuleTestCase
 
 	private bool $treatPhpDocTypesAsCertain = true;
 
+	private bool $polluteScopeWithAlwaysIterableForeach = true;
+
 	protected function getRule(): Rule
 	{
 		return new StrictComparisonOfDifferentTypesRule(
@@ -36,6 +38,11 @@ protected function shouldTreatPhpDocTypesAsCertain(): bool
 		return $this->treatPhpDocTypesAsCertain;
 	}
 
+	protected function shouldPolluteScopeWithAlwaysIterableForeach(): bool
+	{
+		return $this->polluteScopeWithAlwaysIterableForeach;
+	}
+
 	public function testStrictComparison(): void
 	{
 		$tipText = 'Because the type is coming from a PHPDoc, you can turn off this check by setting <fg=cyan>treatPhpDocTypesAsCertain: false</> in your <fg=cyan>%configurationFile%</>.';
@@ -1184,4 +1191,10 @@ public function testBug13421(): void
 		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-13421.php'], []);
 	}
 
+	public function testBug14446(): void
+	{
+		$this->polluteScopeWithAlwaysIterableForeach = false;
+		$this->analyse([__DIR__ . '/../../Analyser/data/bug-14446.php'], []);
+	}
+
 }