diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index de3c4179b22..94510cd3a66 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -3216,9 +3216,34 @@ public function filterBySpecifiedTypes(SpecifiedTypes $specifiedTypes): self
 				if (array_key_exists($conditionalExprString, $conditions)) {
 					continue;
 				}
+
+				// Pass 1: Prefer exact matches
+				foreach ($conditionalExpressions as $conditionalExpression) {
+					foreach ($conditionalExpression->getConditionExpressionTypeHolders() as $holderExprString => $conditionalTypeHolder) {
+						if (
+							!array_key_exists($holderExprString, $specifiedExpressions)
+							|| !$conditionalTypeHolder->equals($specifiedExpressions[$holderExprString])
+						) {
+							continue 2;
+						}
+					}
+
+					$conditions[$conditionalExprString][] = $conditionalExpression;
+					$specifiedExpressions[$conditionalExprString] = $conditionalExpression->getTypeHolder();
+				}
+
+				if (array_key_exists($conditionalExprString, $conditions)) {
+					continue;
+				}
+
+				// Pass 2: Supertype match. Only runs when Pass 1 found no exact match for this expression.
 				foreach ($conditionalExpressions as $conditionalExpression) {
 					foreach ($conditionalExpression->getConditionExpressionTypeHolders() as $holderExprString => $conditionalTypeHolder) {
-						if (!array_key_exists($holderExprString, $specifiedExpressions) || !$specifiedExpressions[$holderExprString]->equals($conditionalTypeHolder)) {
+						if (
+							!array_key_exists($holderExprString, $specifiedExpressions)
+							|| !$conditionalTypeHolder->getCertainty()->equals($specifiedExpressions[$holderExprString]->getCertainty())
+							|| !$conditionalTypeHolder->getType()->isSuperTypeOf($specifiedExpressions[$holderExprString]->getType())->yes()
+						) {
 							continue 2;
 						}
 					}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-10055.php b/tests/PHPStan/Analyser/nsrt/bug-10055.php
new file mode 100644
index 00000000000..2464880ffcc
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-10055.php
@@ -0,0 +1,32 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug10055;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @param 'value1'|'value2'|'value3' $param1
+ * @param ($param1 is 'value3' ? bool : int) $param2
+ */
+function test(string $param1, int|bool $param2): void
+{
+	match ($param1) {
+		'value1' => assertType('int', $param2),
+		'value2' => assertType('int', $param2),
+		'value3' => assertType('bool', $param2),
+	};
+}
+
+function testScopeMerging(mixed $foo): void
+{
+	$a = 0;
+	if (\is_string($foo) || \is_int($foo)) {
+		$a = 1;
+	}
+
+	if (\is_int($foo)) {
+		assertType('1', $a);
+	}
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-10422.php b/tests/PHPStan/Analyser/nsrt/bug-10422.php
new file mode 100644
index 00000000000..5a161575cc6
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-10422.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Bug10422;
+
+use function PHPStan\Testing\assertType;
+
+class TestClass {
+	public function test(): void {}
+	public function something(): bool { return true; }
+}
+
+function test(?TestClass $test): void
+{
+	$error = '';
+
+	if (!$test) {
+		$error = 'missing test';
+	} else if ($test->something()) {
+		$error = 'another';
+	}
+	if ($error) {
+		die('Done');
+	}
+	assertType('Bug10422\TestClass', $test);
+	$test->test();
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-13591.php b/tests/PHPStan/Analyser/nsrt/bug-13591.php
new file mode 100644
index 00000000000..4bdc227cd53
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-13591.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Bug13591;
+
+use function PHPStan\Testing\assertType;
+
+function processHotel(int $hotelId): void {}
+
+/**
+ * @param 'get_rooms'|'get_hotels' $action
+ */
+function test(string $action, ?int $hotelId): void
+{
+	if ($action === 'get_rooms' && $hotelId === null) {
+		throw new \InvalidArgumentException('Hotel ID is required');
+	}
+
+	if ($action === 'get_rooms') {
+		assertType('int', $hotelId);
+		processHotel($hotelId);
+	}
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-4090.php b/tests/PHPStan/Analyser/nsrt/bug-4090.php
new file mode 100644
index 00000000000..6f02233c826
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-4090.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Bug4090;
+
+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(',', $a);
+			break;
+	}
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-5051.php b/tests/PHPStan/Analyser/nsrt/bug-5051.php
index 6c3e80dce11..94ffc4711c8 100644
--- a/tests/PHPStan/Analyser/nsrt/bug-5051.php
+++ b/tests/PHPStan/Analyser/nsrt/bug-5051.php
@@ -60,27 +60,27 @@ public function testWithBooleans($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/bug-6663.php b/tests/PHPStan/Analyser/nsrt/bug-6663.php
new file mode 100644
index 00000000000..228a70b821a
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-6663.php
@@ -0,0 +1,24 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug6663;
+
+use function PHPStan\Testing\assertType;
+
+class X {}
+class Y {}
+
+function test(mixed $xy, mixed $ab): void
+{
+	if ($xy instanceof X || $ab instanceof X) {
+		if ($xy instanceof Y) {
+			assertType('Bug6663\Y', $xy);
+			assertType('Bug6663\X', $ab);
+		}
+		if ($ab instanceof Y) {
+			assertType('Bug6663\X', $xy);
+			assertType('Bug6663\Y', $ab);
+		}
+	}
+}
diff --git a/tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php b/tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php
index 7def992a257..94ba55317c9 100644
--- a/tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php
+++ b/tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php
@@ -1277,4 +1277,11 @@ public function testBug14308(): void
 		$this->analyse([__DIR__ . '/data/bug-14308.php'], []);
 	}
 
+	public function testBug11218(): void
+	{
+		$this->reportPossiblyNonexistentConstantArrayOffset = true;
+
+		$this->analyse([__DIR__ . '/data/bug-11218.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Arrays/data/bug-11218.php b/tests/PHPStan/Rules/Arrays/data/bug-11218.php
new file mode 100644
index 00000000000..e2062abdd66
--- /dev/null
+++ b/tests/PHPStan/Rules/Arrays/data/bug-11218.php
@@ -0,0 +1,18 @@
+<?php declare(strict_types = 1);
+
+namespace Bug11218Array;
+
+function test(): void
+{
+	$level = 'test';
+
+	$test = [];
+
+	for ($i = 0 ; $i <= 3 ; $i++) {
+		if ($i === 0) {
+			$test[$level] = 'this is a';
+		} else {
+			$test[$level] .= ' test';
+		}
+	}
+}
diff --git a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
index 60b40422305..ef5e6865769 100644
--- a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
+++ b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
@@ -2828,4 +2828,14 @@ public function testBug4608(): void
 		]);
 	}
 
+	public function testBug13591(): void
+	{
+		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-13591.php'], []);
+	}
+
+	public function testBug4090(): void
+	{
+		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-4090.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
index 7aca3e79a0b..597b4154b57 100644
--- a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
+++ b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
@@ -4001,4 +4001,12 @@ public function testBug11978(): void
 		]);
 	}
 
+	public function testBug10422(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-10422.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
index b6161df2333..207070c7627 100644
--- a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
+++ b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
@@ -1499,4 +1499,22 @@ public function testBug14117(): void
 		]);
 	}
 
+	public function testBug12597(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = false;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+		$this->analyse([__DIR__ . '/data/bug-12597.php'], []);
+	}
+
+	public function testBug11218(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = false;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+		$this->analyse([__DIR__ . '/data/bug-11218.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Variables/data/bug-11218.php b/tests/PHPStan/Rules/Variables/data/bug-11218.php
new file mode 100644
index 00000000000..aadd9d0cbcf
--- /dev/null
+++ b/tests/PHPStan/Rules/Variables/data/bug-11218.php
@@ -0,0 +1,16 @@
+<?php declare(strict_types = 1);
+
+namespace Bug11218;
+
+function test(): void
+{
+	$level = 'test';
+
+	for ($i = 0 ; $i <= 3 ; $i++) {
+		if ($i === 0) {
+			$test[$level] = 'this is a';
+		} else {
+			$test[$level] .= ' test';
+		}
+	}
+}
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 00000000000..30d1a8654ca
--- /dev/null
+++ b/tests/PHPStan/Rules/Variables/data/bug-12597.php
@@ -0,0 +1,24 @@
+<?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 {}
+}