diff --git a/src/Rules/Comparison/ImpossibleCheckTypeHelper.php b/src/Rules/Comparison/ImpossibleCheckTypeHelper.php
index 0551a2b2d1..ab412e21ec 100644
--- a/src/Rules/Comparison/ImpossibleCheckTypeHelper.php
+++ b/src/Rules/Comparison/ImpossibleCheckTypeHelper.php
@@ -68,11 +68,12 @@ public function findSpecifiedType(
 			if ($node->isFirstClassCallable()) {
 				return null;
 			}
-			$argsCount = count($node->getArgs());
+			$args = $node->getArgs();
+			$argsCount = count($args);
 			if ($node->name instanceof Node\Name) {
 				$functionName = strtolower((string) $node->name);
 				if ($functionName === 'assert' && $argsCount >= 1) {
-					$arg = $node->getArgs()[0]->value;
+					$arg = $args[0]->value;
 					$assertValue = ($this->treatPhpDocTypesAsCertain ? $scope->getType($arg) : $scope->getNativeType($arg))->toBoolean();
 					$assertValueIsTrue = $assertValue->isTrue()->yes();
 					if (! $assertValueIsTrue && ! $assertValue->isFalse()->yes()) {
@@ -96,7 +97,7 @@ public function findSpecifiedType(
 				} elseif ($functionName === 'array_search') {
 					return null;
 				} elseif ($functionName === 'in_array' && $argsCount >= 2) {
-					$haystackArg = $node->getArgs()[1]->value;
+					$haystackArg = $args[1]->value;
 					$haystackType = ($this->treatPhpDocTypesAsCertain ? $scope->getType($haystackArg) : $scope->getNativeType($haystackArg));
 					if ($haystackType instanceof MixedType) {
 						return null;
@@ -106,12 +107,12 @@ public function findSpecifiedType(
 						return null;
 					}
 
-					$needleArg = $node->getArgs()[0]->value;
+					$needleArg = $args[0]->value;
 					$needleType = ($this->treatPhpDocTypesAsCertain ? $scope->getType($needleArg) : $scope->getNativeType($needleArg));
 
 					$isStrictComparison = false;
 					if ($argsCount >= 3) {
-						$strictNodeType = $scope->getType($node->getArgs()[2]->value);
+						$strictNodeType = $scope->getType($args[2]->value);
 						$isStrictComparison = $strictNodeType->isTrue()->yes();
 					}
 
@@ -192,7 +193,7 @@ public function findSpecifiedType(
 						}
 					}
 				} elseif ($functionName === 'method_exists' && $argsCount >= 2) {
-					$objectArg = $node->getArgs()[0]->value;
+					$objectArg = $args[0]->value;
 					$objectType = ($this->treatPhpDocTypesAsCertain ? $scope->getType($objectArg) : $scope->getNativeType($objectArg));
 
 					if ($objectType instanceof ConstantStringType
@@ -201,7 +202,7 @@ public function findSpecifiedType(
 						return false;
 					}
 
-					$methodArg = $node->getArgs()[1]->value;
+					$methodArg = $args[1]->value;
 					$methodType = ($this->treatPhpDocTypesAsCertain ? $scope->getType($methodArg) : $scope->getNativeType($methodArg));
 
 					if ($methodType instanceof ConstantStringType) {
@@ -278,6 +279,16 @@ public function findSpecifiedType(
 
 		$results = [];
 
+		$assignedInCallVars = [];
+		if ($node instanceof Expr\CallLike) {
+			foreach ($node->getArgs() as $arg) {
+				if (!$arg->value instanceof Expr\Assign) {
+					continue;
+				}
+
+				$assignedInCallVars[] = $arg->value;
+			}
+		}
 		foreach ($sureTypes as $sureType) {
 			if (self::isSpecified($typeSpecifierScope, $node, $sureType[0])) {
 				$results[] = TrinaryLogic::createMaybe();
@@ -293,6 +304,14 @@ public function findSpecifiedType(
 			/** @var Type $resultType */
 			$resultType = $sureType[1];
 
+			foreach ($assignedInCallVars as $assignedInCallVar) {
+				if ($sureType[0] !== $assignedInCallVar->var) {
+					continue;
+				}
+
+				$argumentType = $scope->getType($assignedInCallVar->expr);
+			}
+
 			$results[] = $resultType->isSuperTypeOf($argumentType)->result;
 		}
 
diff --git a/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php b/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php
index 132ec6bfa2..2c0c7fbbfe 100644
--- a/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php
+++ b/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php
@@ -1032,4 +1032,53 @@ public function testBug13291(): void
 		$this->analyse([__DIR__ . '/data/bug-13291.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testBug13268(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-13268.php'], []);
+	}
+
+	#[RequiresPhp('>= 8.1')]
+	public function testBug12087(): 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%</>.';
+
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-12087.php'], [
+			[
+				'Call to function is_null() with null will always evaluate to true.',
+				14,
+				$tipText,
+			],
+		]);
+	}
+
+	public function testBug9666(): 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%</>.';
+
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-9666.php'], [
+			[
+				'Call to function is_bool() with bool will always evaluate to true.',
+				20,
+				$tipText,
+			],
+		]);
+	}
+
+	#[RequiresPhp('>= 8.0')]
+	public function testBug9445(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-9445.php'], []);
+	}
+
+	public function testBug7773(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-7773.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeMethodCallRuleTest.php b/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeMethodCallRuleTest.php
index 3fd625a4b1..fb64511aff 100644
--- a/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeMethodCallRuleTest.php
+++ b/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeMethodCallRuleTest.php
@@ -275,6 +275,21 @@ public function testBug12473(): void
 		]);
 	}
 
+	#[RequiresPhp('>= 8.1')]
+	public function testBug12087b(): 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%</>.';
+
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-12087b.php'], [
+			[
+				'Call to method Bug12087b\MyAssert::is_null() with null will always evaluate to true.',
+				37,
+				$tipText,
+			],
+		]);
+	}
+
 	public static function getAdditionalConfigFiles(): array
 	{
 		return [
diff --git a/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeStaticMethodCallRuleTest.php b/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeStaticMethodCallRuleTest.php
index 1b43cdea9d..8a68085379 100644
--- a/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeStaticMethodCallRuleTest.php
+++ b/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeStaticMethodCallRuleTest.php
@@ -5,6 +5,7 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Testing\RuleTestCase;
 use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\RequiresPhp;
 
 /**
  * @extends RuleTestCase<ImpossibleCheckTypeStaticMethodCallRule>
@@ -145,6 +146,21 @@ public function testReportAlwaysTrueInLastCondition(bool $reportAlwaysTrueInLast
 		$this->analyse([__DIR__ . '/data/impossible-static-method-report-always-true-last-condition.php'], $expectedErrors);
 	}
 
+	#[RequiresPhp('>= 8.1')]
+	public function testBug12087b(): 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%</>.';
+
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-12087b.php'], [
+			[
+				'Call to static method Bug12087b\MyAssert::static_is_null() with null will always evaluate to true.',
+				31,
+				$tipText,
+			],
+		]);
+	}
+
 	public static function getAdditionalConfigFiles(): array
 	{
 		return [
diff --git a/tests/PHPStan/Rules/Comparison/data/bug-12087.php b/tests/PHPStan/Rules/Comparison/data/bug-12087.php
new file mode 100644
index 0000000000..31b18128b1
--- /dev/null
+++ b/tests/PHPStan/Rules/Comparison/data/bug-12087.php
@@ -0,0 +1,15 @@
+<?php // lint >= 8.1
+
+namespace Bug12087;
+
+enum Button: int
+{
+	case On = 1;
+
+	case Off = 0;
+}
+
+$value = 10;
+
+is_null($value = Button::tryFrom($value));
+
diff --git a/tests/PHPStan/Rules/Comparison/data/bug-12087b.php b/tests/PHPStan/Rules/Comparison/data/bug-12087b.php
new file mode 100644
index 0000000000..3c26c567e9
--- /dev/null
+++ b/tests/PHPStan/Rules/Comparison/data/bug-12087b.php
@@ -0,0 +1,38 @@
+<?php // lint >= 8.1
+
+namespace Bug12087b;
+
+enum Button: int
+{
+	case On = 1;
+
+	case Off = 0;
+}
+
+class MyAssert {
+	/**
+	 * @return ($value is null ? true : false)
+	 */
+	static public function static_is_null(mixed $value): bool {
+		return $value === null;
+	}
+
+	/**
+	 * @return ($value is null ? true : false)
+	 */
+	public function is_null(mixed $value): bool {
+		return $value === null;
+	}
+}
+
+function doFoo(): void {
+	$value = 10;
+
+	MyAssert::static_is_null($value = Button::tryFrom($value));
+}
+
+function doBar(MyAssert $assert): void {
+	$value = 10;
+
+	$assert->is_null($value = Button::tryFrom($value));
+}
diff --git a/tests/PHPStan/Rules/Comparison/data/bug-13268.php b/tests/PHPStan/Rules/Comparison/data/bug-13268.php
new file mode 100644
index 0000000000..0bdbd130eb
--- /dev/null
+++ b/tests/PHPStan/Rules/Comparison/data/bug-13268.php
@@ -0,0 +1,28 @@
+<?php declare(strict_types = 1);
+
+namespace Bug13268;
+
+class HelloWorld
+{
+	public function assignInCall(string $string): ?string
+	{
+		if (
+			is_string(
+				$string = realpath($string)
+			)
+		) {
+			throw new \RuntimeException('Refusing to overwrite existing file: ' . $string);
+		}
+		return null;
+	}
+
+	public function dumpToLog(mixed $dumpToLog): ?string
+	{
+		if (is_string($dumpToLog)) {
+			if (file_exists($dumpToLog) || is_string($dumpToLog = realpath($dumpToLog))) {
+				throw new \RuntimeException('Refusing to overwrite existing file: ' . $dumpToLog);
+			}
+		}
+		return null;
+	}
+}
diff --git a/tests/PHPStan/Rules/Comparison/data/bug-7773.php b/tests/PHPStan/Rules/Comparison/data/bug-7773.php
new file mode 100644
index 0000000000..f7619b92a1
--- /dev/null
+++ b/tests/PHPStan/Rules/Comparison/data/bug-7773.php
@@ -0,0 +1,40 @@
+<?php declare(strict_types=1);
+
+namespace Bug7773;
+
+class JSONEncodingException extends \Exception
+{
+}
+
+class JSONDecodingException extends \Exception
+{
+}
+
+class HelloWorld
+{
+	/**
+	 * Encodes the data as JSON
+	 * @param array<mixed> $data json array
+	 * @return string json string
+	 * @throws JSONEncodingException
+	 */
+	public static function JSONEncode(array $data): string
+	{
+		if (!is_string($data = json_encode($data)))
+			throw new JSONEncodingException();
+		return $data;
+	}
+
+	/**
+	 * Decodes the JSON data as an array
+	 * @param string $data json string
+	 * @return array<mixed> json array
+	 * @throws JSONDecodingException
+	 */
+	public static function JSONDecode(string $data): array
+	{
+		if (!is_array($data = json_decode($data, true)))
+			throw new JSONDecodingException();
+		return $data;
+	}
+}
diff --git a/tests/PHPStan/Rules/Comparison/data/bug-9445.php b/tests/PHPStan/Rules/Comparison/data/bug-9445.php
new file mode 100644
index 0000000000..8fd828d0cc
--- /dev/null
+++ b/tests/PHPStan/Rules/Comparison/data/bug-9445.php
@@ -0,0 +1,22 @@
+<?php // lint >= 8.0
+
+declare(strict_types=1);
+
+namespace Bug9445;
+
+class Foo
+{
+	public int $id;
+	public null|self $parent;
+
+	public function contains(self $foo): bool
+	{
+		do {
+			if ($this->id === $foo->id) {
+				return true;
+			}
+		} while (!is_null($foo = $foo->parent));
+
+		return false;
+	}
+}
diff --git a/tests/PHPStan/Rules/Comparison/data/bug-9666.php b/tests/PHPStan/Rules/Comparison/data/bug-9666.php
new file mode 100644
index 0000000000..028601f5c2
--- /dev/null
+++ b/tests/PHPStan/Rules/Comparison/data/bug-9666.php
@@ -0,0 +1,24 @@
+<?php declare(strict_types=1);
+
+namespace Bug9666;
+
+class A
+{
+	/**
+	 * @return array<int,bool>
+	 */
+	function b()
+	{
+		return [];
+	}
+}
+
+function doFoo() {
+	$a = new A();
+	$b = $a->b();
+	$c = null;
+	if ($b && is_bool($c = reset($b))) {
+		//
+	}
+}
+