diff --git a/src/Analyser/NodeScopeResolver.php b/src/Analyser/NodeScopeResolver.php
index 72f087b400..f3904f0274 100644
--- a/src/Analyser/NodeScopeResolver.php
+++ b/src/Analyser/NodeScopeResolver.php
@@ -1453,6 +1453,11 @@ public function processStmtNode(
 				$stmt->expr,
 				new Array_([]),
 			);
+			// Inside the loop body the iterated expression is provably non-empty, so
+			// narrow it (list -> non-empty-list, array -> non-empty-array) at body entry
+			// from the pre-loop scope. This is independent of polluteScopeWithAlwaysIterableForeach,
+			// which only controls what leaks into the after-loop scope.
+			$nonEmptyIterateeScope = $scope->filterByTruthyValue($arrayComparisonExpr);
 			$this->callNodeCallback($nodeCallback, new InForeachNode($stmt), $scope, $storage);
 			$originalScope = $scope;
 			$bodyScope = $scope;
@@ -1475,7 +1480,7 @@ public function processStmtNode(
 			if ($context->isTopLevel()) {
 				$storage = $originalStorage->duplicate();
 
-				$originalScope = $this->polluteScopeWithAlwaysIterableForeach ? $scope->filterByTruthyValue($arrayComparisonExpr) : $scope;
+				$originalScope = $nonEmptyIterateeScope;
 				$unrolledResult = $this->tryProcessUnrolledConstantArrayForeach($stmt, $originalScope, $originalStorage, $context);
 				if ($unrolledResult !== null) {
 					$bodyScope = $unrolledResult['bodyScope'];
@@ -1486,7 +1491,7 @@ public function processStmtNode(
 					$count = 0;
 					do {
 						$prevScope = $bodyScope;
-						$bodyScope = $bodyScope->mergeWith($this->polluteScopeWithAlwaysIterableForeach ? $scope->filterByTruthyValue($arrayComparisonExpr) : $scope);
+						$bodyScope = $bodyScope->mergeWith($nonEmptyIterateeScope);
 						$storage = $originalStorage->duplicate();
 						$bodyScope = $this->enterForeach($bodyScope, $storage, $originalScope, $stmt, $nodeCallback);
 						$bodyScopeResult = $this->processStmtNodesInternal($stmt, $stmt->stmts, $bodyScope, $storage, new NoopNodeCallback(), $context->enterDeep())->filterOutLoopExitPoints();
@@ -1506,7 +1511,7 @@ public function processStmtNode(
 				}
 			}
 
-			$bodyScope = $bodyScope->mergeWith($this->polluteScopeWithAlwaysIterableForeach ? $scope->filterByTruthyValue($arrayComparisonExpr) : $scope);
+			$bodyScope = $bodyScope->mergeWith($nonEmptyIterateeScope);
 			$storage = $originalStorage;
 			$bodyScope = $this->enterForeach($bodyScope, $storage, $originalScope, $stmt, $nodeCallback);
 			$finalPassContext = $unrolledTotalKeys !== null ? $context->enterUnrolledForeach($unrolledTotalKeys) : $context;
diff --git a/src/Command/AnalyseCommand.php b/src/Command/AnalyseCommand.php
index 5b3be09c6b..64d55f8da4 100644
--- a/src/Command/AnalyseCommand.php
+++ b/src/Command/AnalyseCommand.php
@@ -477,8 +477,8 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 		if ($generateBaselineFile !== null) {
 			$this->runDiagnoseExtensions($container, $inceptionResult->getErrorOutput(), $analysisResult->getProcessedFiles());
 			if (count($internalErrorsTuples) > 0) {
-				foreach ($internalErrorsTuples as [$internalError]) {
-					$inceptionResult->getStdOutput()->writeLineFormatted($internalError->getMessage());
+				foreach ($internalErrorsTuples as [$error]) {
+					$inceptionResult->getStdOutput()->writeLineFormatted($error->getMessage());
 					$inceptionResult->getStdOutput()->writeLineFormatted('');
 				}
 
diff --git a/src/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocator.php b/src/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocator.php
index b83b5a35a1..8c4b70d805 100644
--- a/src/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocator.php
+++ b/src/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocator.php
@@ -134,8 +134,8 @@ public function locateIdentifier(Reflector $reflector, Identifier $identifier):
 		if ($identifier->isClass()) {
 			$fetchedClassNode = null;
 			$fetchedFile = null;
-			foreach ($files as $file) {
-				$fetchedClassNodes = $this->fileNodesFetcher->fetchNodes($file)->getClassNodes();
+			foreach ($files as $sourceFile) {
+				$fetchedClassNodes = $this->fileNodesFetcher->fetchNodes($sourceFile)->getClassNodes();
 
 				if (!array_key_exists($identifierName, $fetchedClassNodes)) {
 					return null;
@@ -143,7 +143,7 @@ public function locateIdentifier(Reflector $reflector, Identifier $identifier):
 
 				/** @var FetchedNode<Node\Stmt\ClassLike> $fetchedClassNode */
 				$fetchedClassNode = current($fetchedClassNodes[$identifierName]);
-				$fetchedFile = $file;
+				$fetchedFile = $sourceFile;
 			}
 
 			[$reflectionCacheKey, $variableCacheKey] = $this->getCacheKeys($fetchedFile, $identifier);
diff --git a/src/Type/Constant/ConstantArrayType.php b/src/Type/Constant/ConstantArrayType.php
index 7eca2eaa58..60372869ae 100644
--- a/src/Type/Constant/ConstantArrayType.php
+++ b/src/Type/Constant/ConstantArrayType.php
@@ -811,7 +811,11 @@ public function isSuperTypeOf(Type $type): IsSuperTypeOfResult
 						continue;
 					}
 
-					[$thisUnsealedKey, $thisUnsealedValue] = $this->unsealed;
+					$thisUnsealed = $this->unsealed;
+					if ($thisUnsealed === null) {
+						throw new ShouldNotHappenException();
+					}
+					[$thisUnsealedKey, $thisUnsealedValue] = $thisUnsealed;
 					$keyCheck = $thisUnsealedKey->isSuperTypeOf($typeKey);
 					if ($keyCheck->no()) {
 						if ($type->isOptionalKey($i)) {
@@ -835,8 +839,13 @@ public function isSuperTypeOf(Type $type): IsSuperTypeOfResult
 					if ($thisUnsealedness->no()) {
 						$results[] = IsSuperTypeOfResult::createMaybe();
 					} else {
-						[$thisUnsealedKey, $thisUnsealedValue] = $this->unsealed;
-						[$typeUnsealedKey, $typeUnsealedValue] = $type->unsealed;
+						$thisUnsealed = $this->unsealed;
+						$typeUnsealed = $type->unsealed;
+						if ($thisUnsealed === null || $typeUnsealed === null) {
+							throw new ShouldNotHappenException();
+						}
+						[$thisUnsealedKey, $thisUnsealedValue] = $thisUnsealed;
+						[$typeUnsealedKey, $typeUnsealedValue] = $typeUnsealed;
 						$results[] = $thisUnsealedKey->isSuperTypeOf($typeUnsealedKey);
 						$results[] = $thisUnsealedValue->isSuperTypeOf($typeUnsealedValue);
 					}
diff --git a/src/Type/UnionType.php b/src/Type/UnionType.php
index 011cdec938..b8dca23375 100644
--- a/src/Type/UnionType.php
+++ b/src/Type/UnionType.php
@@ -239,9 +239,9 @@ public function accepts(Type $type, bool $strictTypes): AcceptsResult
 		}
 		if ($commonReasons !== null && count($commonReasons) > 0) {
 			$decorated = [];
-			foreach (array_keys($innerAccepts) as $i) {
+			foreach (array_keys($innerAccepts) as $j) {
 				foreach ($commonReasons as $reason) {
-					$decorated[] = sprintf('Type #%d from the union: %s', $i + 1, $reason);
+					$decorated[] = sprintf('Type #%d from the union: %s', $j + 1, $reason);
 				}
 			}
 			$result = new AcceptsResult($result->result, $decorated);
diff --git a/tests/PHPStan/Analyser/Bug13312NoPolluteTest.php b/tests/PHPStan/Analyser/Bug13312NoPolluteTest.php
new file mode 100644
index 0000000000..43f89c0d88
--- /dev/null
+++ b/tests/PHPStan/Analyser/Bug13312NoPolluteTest.php
@@ -0,0 +1,36 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Analyser;
+
+use PHPStan\Testing\TypeInferenceTestCase;
+use PHPUnit\Framework\Attributes\DataProvider;
+
+class Bug13312NoPolluteTest extends TypeInferenceTestCase
+{
+
+	public static function dataFileAsserts(): iterable
+	{
+		yield from self::gatherAssertTypes(__DIR__ . '/data/bug-13312-no-pollute.php');
+	}
+
+	/**
+	 * @param mixed ...$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-13312-no-pollute.neon',
+		];
+	}
+
+}
diff --git a/tests/PHPStan/Analyser/bug-13312-no-pollute.neon b/tests/PHPStan/Analyser/bug-13312-no-pollute.neon
new file mode 100644
index 0000000000..3ee516d3be
--- /dev/null
+++ b/tests/PHPStan/Analyser/bug-13312-no-pollute.neon
@@ -0,0 +1,2 @@
+parameters:
+	polluteScopeWithAlwaysIterableForeach: false
diff --git a/tests/PHPStan/Analyser/data/bug-13312-no-pollute.php b/tests/PHPStan/Analyser/data/bug-13312-no-pollute.php
new file mode 100644
index 0000000000..2926f97297
--- /dev/null
+++ b/tests/PHPStan/Analyser/data/bug-13312-no-pollute.php
@@ -0,0 +1,37 @@
+<?php declare(strict_types = 1);
+
+namespace Bug13312NoPollute;
+
+use function PHPStan\Testing\assertType;
+
+/** @param list<mixed> $arr */
+function foo(array $arr): void {
+	assertType('list<mixed>', $arr);
+	foreach ($arr as $v) {
+		assertType('non-empty-list<mixed>', $arr);
+	}
+	assertType('list<mixed>', $arr);
+
+	for ($i = 0; $i < count($arr); ++$i) {
+		assertType('non-empty-list<mixed>', $arr);
+	}
+	assertType('list<mixed>', $arr);
+}
+
+/** @param array<string, int> $arr */
+function fooStringKeyed(array $arr): void {
+	assertType('array<string, int>', $arr);
+	foreach ($arr as $v) {
+		assertType('non-empty-array<string, int>', $arr);
+	}
+	assertType('array<string, int>', $arr);
+}
+
+/** @param list<mixed> $arr */
+function fooReassign(array $arr): void {
+	foreach ($arr as $v) {
+		$arr = [];
+		assertType('array{}', $arr);
+	}
+	assertType('array{}', $arr);
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-13312.php b/tests/PHPStan/Analyser/nsrt/bug-13312.php
index 3a7ab22873..9a47594a06 100644
--- a/tests/PHPStan/Analyser/nsrt/bug-13312.php
+++ b/tests/PHPStan/Analyser/nsrt/bug-13312.php
@@ -32,6 +32,24 @@ function foo(array $arr): void {
 }
 
 
+/** @param array<string, int> $arr */
+function fooStringKeyed(array $arr): void {
+	assertType('array<string, int>', $arr);
+	foreach ($arr as $v) {
+		assertType('non-empty-array<string, int>', $arr);
+	}
+	assertType('array<string, int>', $arr);
+}
+
+/** @param list<mixed> $arr */
+function fooReassign(array $arr): void {
+	foreach ($arr as $v) {
+		$arr = [];
+		assertType('array{}', $arr);
+	}
+	assertType('array{}', $arr);
+}
+
 function fooBar(mixed $mixed): void {
 	assertType('mixed', $mixed);
 	foreach ($mixed as $v) {
diff --git a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
index ca23663401..a4add283d7 100644
--- a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
+++ b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
@@ -961,10 +961,6 @@ public function testBug8467c(): void
 				'Variable $v might not be defined.',
 				16,
 			],
-			[
-				'Variable $v might not be defined.',
-				18,
-			],
 		]);
 	}