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

src/Analyser/MutatingScope.php

@@ -3870,14 +3870,32 @@ public function processAlwaysIterableForeachScopeWithoutPollute(self $finalScope
 			);
 		}
 
+		$conditionalExpressions = $this->conditionalExpressions;
+		foreach ($this->conditionalExpressions as $conditionalExprString => $holders) {
+			foreach ($holders as $holder) {
+				foreach (array_keys($holder->getConditionExpressionTypeHolders()) as $holderExprString) {
+					if (!isset($finalScope->expressionTypes[$holderExprString])) {
+						continue 2;
+					}
+					if (!isset($this->expressionTypes[$holderExprString])) {
+						continue 2;
+					}
+					if (!$this->expressionTypes[$holderExprString]->getType()->equals($finalScope->expressionTypes[$holderExprString]->getType())) {
+						unset($conditionalExpressions[$conditionalExprString]);
+						continue 3;
+					}
+				}
+			}
+		}
+
 		return $this->scopeFactory->create(
 			$this->context,
 			$this->isDeclareStrictTypes(),
 			$this->getFunction(),
 			$this->getNamespace(),
 			$expressionTypes,
 			$nativeTypes,
-			$this->conditionalExpressions,
+			$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 +1,49 @@
+<?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);
+}
+
+/**
+ * @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);
+			}
+		}
+	}
+}