diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index a43ba35dda..a941e3799b 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -3217,13 +3217,36 @@ public function filterBySpecifiedTypes(SpecifiedTypes $specifiedTypes): self
 					continue;
 				}
 				foreach ($conditionalExpressions as $conditionalExpression) {
+					$subtypeMatch = false;
 					foreach ($conditionalExpression->getConditionExpressionTypeHolders() as $holderExprString => $conditionalTypeHolder) {
-						if (!array_key_exists($holderExprString, $specifiedExpressions) || !$specifiedExpressions[$holderExprString]->equals($conditionalTypeHolder)) {
+						if (!array_key_exists($holderExprString, $specifiedExpressions)) {
 							continue 2;
 						}
+						$specifiedHolder = $specifiedExpressions[$holderExprString];
+						if ($specifiedHolder->equals($conditionalTypeHolder)) {
+							continue;
+						}
+
+						$guardType = $conditionalTypeHolder->getType();
+						$specifiedType = $specifiedHolder->getType();
+						if (
+							$conditionalExpression->getTypeHolder()->getCertainty()->yes()
+							&& $specifiedHolder->getCertainty()->yes()
+							&& $conditionalTypeHolder->getCertainty()->yes()
+							&& $guardType->isOffsetAccessible()->no()
+							&& $guardType->isSuperTypeOf($specifiedType)->yes()
+						) {
+							$subtypeMatch = true;
+							continue;
+						}
+						continue 2;
 					}
 
 					$conditions[$conditionalExprString][] = $conditionalExpression;
+					if ($subtypeMatch) {
+						continue;
+					}
+
 					$specifiedExpressions[$conditionalExprString] = $conditionalExpression->getTypeHolder();
 				}
 			}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-10422.php b/tests/PHPStan/Analyser/nsrt/bug-10422.php
new file mode 100644
index 0000000000..3b910a253b
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-10422.php
@@ -0,0 +1,42 @@
+<?php declare(strict_types = 1);
+
+namespace Bug10422;
+
+use stdClass;
+use function PHPStan\Testing\assertType;
+
+class Foo
+{
+
+	public function something(): bool
+	{
+		return true;
+	}
+
+	public function test(): void
+	{
+	}
+
+}
+
+function createOrNotObject(): ?Foo
+{
+	return new Foo();
+}
+
+function testSimple(): void
+{
+	$test = createOrNotObject();
+
+	$error = '';
+
+	if (!$test) {
+		$error = 'missing test';
+	} else if ($test->something()) {
+		$error = 'another';
+	}
+	if ($error) {
+		die('Done');
+	}
+	assertType(Foo::class, $test);
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-11218.php b/tests/PHPStan/Analyser/nsrt/bug-11218.php
new file mode 100644
index 0000000000..c538164edd
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-11218.php
@@ -0,0 +1,23 @@
+<?php declare(strict_types = 1);
+
+namespace Bug11218;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+
+	public function test(): void
+	{
+		$level = 'foo';
+		for ($i = 1; $i <= 3; $i++) {
+			if ($i === 0) {
+				$test[$level] = 'this is a';
+			} else {
+				assertType("array{test: literal-string&lowercase-string&non-falsy-string}", $test);
+				$test[$level] .= ' test';
+			}
+		}
+	}
+
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-13591.php b/tests/PHPStan/Analyser/nsrt/bug-13591.php
new file mode 100644
index 0000000000..5a301b3733
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-13591.php
@@ -0,0 +1,22 @@
+<?php declare(strict_types = 1);
+
+namespace Bug13591;
+
+use InvalidArgumentException;
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+
+	public function test(string $action, ?int $hotelId): void
+	{
+		if (($action === 'get_rooms' || $action === 'get_rooms_2') && $hotelId === null) {
+			throw new InvalidArgumentException('Hotel ID is required');
+		}
+
+		if ($action === 'get_rooms') {
+			assertType('int', $hotelId);
+		}
+	}
+
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-4090.php b/tests/PHPStan/Analyser/nsrt/bug-4090.php
new file mode 100644
index 0000000000..5e4ee28a42
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-4090.php
@@ -0,0 +1,47 @@
+<?php declare(strict_types = 1);
+
+namespace Bug4090;
+
+use function current;
+use function PHPStan\Testing\assertType;
+
+/** @param string[] $a */
+function foo(array $a): void
+{
+	if (count($a) > 1) {
+		echo implode(',', $a);
+	} elseif (count($a) === 1) {
+		assertType('string', current($a));
+		echo trim(current($a));
+	}
+}
+
+
+/** @param string[] $a */
+function bar(array $a): void
+{
+	$count = count($a);
+	if ($count > 1) {
+		echo implode(',', $a);
+	} elseif ($count === 1) {
+		assertType('string', current($a));
+		echo trim(current($a));
+	}
+}
+
+
+/** @param string[] $a */
+function qux(array $a): void
+{
+	switch (count($a)) {
+		case 0:
+			break;
+		case 1:
+			assertType('string', current($a));
+			echo trim(current($a));
+			break;
+		default:
+			echo implode(',', $a);
+			break;
+	}
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-5051.php b/tests/PHPStan/Analyser/nsrt/bug-5051.php
index 6c3e80dce1..94ffc4711c 100644
--- a/tests/PHPStan/Analyser/nsrt/bug-5051.php
+++ b/tests/PHPStan/Analyser/nsrt/bug-5051.php
@@ -60,27 +60,27 @@ public function testWithBooleans($data): void
 			assertType('bool', $update);
 		} else {
 			assertType('1|2', $data);
-			assertType('bool', $update);
+			assertType('false', $update);
 		}
 
 		if ($data === 1) {
-			assertType('bool', $update);
-			assertType('bool', $foo);
+			assertType('false', $update);
+			assertType('false', $foo);
 		} else {
 			assertType('bool', $update);
 			assertType('bool', $foo);
 		}
 
 		if ($data === 2) {
-			assertType('bool', $update);
-			assertType('bool', $foo);
+			assertType('false', $update);
+			assertType('false', $foo);
 		} else {
 			assertType('bool', $update);
 			assertType('bool', $foo);
 		}
 
 		if ($data === 3) {
-			assertType('bool', $update);
+			assertType('false', $update);
 			assertType('true', $foo);
 		} else {
 			assertType('bool', $update);
@@ -88,7 +88,7 @@ public function testWithBooleans($data): void
 		}
 
 		if ($data === 1 || $data === 2) {
-			assertType('bool', $update);
+			assertType('false', $update);
 			assertType('false', $foo);
 		} else {
 			assertType('bool', $update);
diff --git a/tests/PHPStan/Analyser/nsrt/pr-5379.php b/tests/PHPStan/Analyser/nsrt/pr-5379.php
new file mode 100644
index 0000000000..e349626134
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/pr-5379.php
@@ -0,0 +1,70 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PR5379;
+
+use ArrayAccess;
+
+use function PHPStan\Testing\assertType;
+
+class AggregationParser
+{
+	/**
+	 * @param array<string, mixed> $aggregation
+	 */
+	private function parseAggregation(array $aggregation)
+	{
+		$type = $aggregation['type'] ?? null;
+		if (!\is_string($type) || empty($type) || is_numeric($type)) {
+			return null;
+		}
+
+		if (empty($aggregation['field']) && $type !== 'filter') {
+			return null;
+		}
+
+		$field = '';
+		if ($type !== 'filter') {
+			$field = self::buildFieldName();
+		}
+
+		assertType('non-falsy-string', $type);
+	}
+
+	private static function buildFieldName(): string
+	{
+		return 'field';
+	}
+}
+
+class AggregationParser2
+{
+	private function parseAggregation(string $aggregation, string $type)
+	{
+		if (empty($aggregation[1]) && $type !== 'filter') {
+			return null;
+		}
+		assertType('string', $type);
+
+		if ($type !== 'filter') {
+			assertType('string', $type);
+		}
+
+		assertType('string', $type);
+	}
+
+	private function parseAggregation2(ArrayAccess $aggregation, string $type)
+	{
+		if (empty($aggregation['foo']) && $type !== 'filter') {
+			return null;
+		}
+		assertType('string', $type);
+
+		if ($type !== 'filter') {
+			assertType('string', $type);
+		}
+
+		assertType('string', $type);
+	}
+}
diff --git a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
index b6161df233..21e0a6dd74 100644
--- a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
+++ b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
@@ -1476,6 +1476,25 @@ public function testBug14227(): void
 		$this->analyse([__DIR__ . '/data/bug-14227.php'], []);
 	}
 
+	public function testBug12597(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = false;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+		$this->analyse([__DIR__ . '/data/bug-12597.php'], []);
+	}
+
+	#[RequiresPhp('>= 8.0')]
+	public function testBug12597NonFinite(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = false;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+		$this->analyse([__DIR__ . '/data/bug-12597-non-finite.php'], []);
+	}
+
 	public function testBug14117(): void
 	{
 		$this->cliArgumentsVariablesRegistered = true;
diff --git a/tests/PHPStan/Rules/Variables/data/bug-12597-non-finite.php b/tests/PHPStan/Rules/Variables/data/bug-12597-non-finite.php
new file mode 100644
index 0000000000..3b42da95f0
--- /dev/null
+++ b/tests/PHPStan/Rules/Variables/data/bug-12597-non-finite.php
@@ -0,0 +1,51 @@
+<?php declare(strict_types = 1);
+
+namespace Bug12597NonFinite;
+
+class HelloWorld
+{
+	public function test(mixed $type): void
+	{
+		if (is_int($type) || is_string($type)) {
+			$message = 'Hello!';
+		}
+
+		if (is_int($type)) {
+			$this->message($message);
+		}
+	}
+
+	public function message(string $message): void {}
+}
+
+class Foo {}
+class Bar {}
+
+class HelloWorld2
+{
+	public function test(mixed $type): void
+	{
+		if (is_int($type) || is_object($type)) {
+			$message = 'Hello!';
+		}
+
+		if (is_int($type)) {
+			$this->message($message);
+		}
+	}
+
+	public function test2(mixed $type): void
+	{
+		if ($type instanceof Foo || $type instanceof Bar) {
+			$message = 'Hello!';
+		}
+
+		if ($type instanceof Foo) {
+			$this->message($message);
+		}
+	}
+
+	public function message(string $message): void
+	{
+	}
+}
diff --git a/tests/PHPStan/Rules/Variables/data/bug-12597.php b/tests/PHPStan/Rules/Variables/data/bug-12597.php
new file mode 100644
index 0000000000..2cfdf45974
--- /dev/null
+++ b/tests/PHPStan/Rules/Variables/data/bug-12597.php
@@ -0,0 +1,22 @@
+<?php declare(strict_types = 1);
+
+namespace Bug12597;
+
+class HelloWorld
+{
+	private const TYPE_1 = 1;
+	private const TYPE_2 = 2;
+
+	public function test(int $type): void
+	{
+		if (in_array($type, [self::TYPE_1, self::TYPE_2], true)) {
+			$message = 'Hello!';
+		}
+
+		if ($type === self::TYPE_1) {
+			$this->message($message);
+		}
+	}
+
+	public function message(string $message): void {}
+}