Understand that new Foo() cannot be a subclass

src/Analyser/MutatingScope.php

@@ -5599,6 +5599,10 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 		}
 
 		$classReflection = $this->reflectionProvider->getClass($resolvedClassName);
+		$nonFinalClassReflection = $classReflection;
+		if (!$isStatic) {
+			$classReflection = $classReflection->asFinal();
+		}
 		if ($classReflection->hasConstructor()) {
 			$constructorMethod = $classReflection->getConstructor();
 		} else {
@@ -5648,7 +5652,7 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 			return $methodResult;
 		}
 
-		$objectType = $isStatic ? new StaticType($classReflection) : new ObjectType($resolvedClassName);
+		$objectType = $isStatic ? new StaticType($classReflection) : new ObjectType($resolvedClassName, null, $classReflection);
 		if (!$classReflection->isGeneric()) {
 			return $objectType;
 		}
@@ -5674,7 +5678,8 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 
 			if (count($classTemplateTypes) === count($originalClassTemplateTypes)) {
 				$propertyType = TypeCombinator::removeNull($this->getType($assignedToProperty));
-				if ($objectType->isSuperTypeOf($propertyType)->yes()) {
+				$nonFinalObjectType = $isStatic ? new StaticType($nonFinalClassReflection) : new ObjectType($resolvedClassName, null, $nonFinalClassReflection);
+				if ($nonFinalObjectType->isSuperTypeOf($propertyType)->yes()) {
 					return $propertyType;
 				}
 			}
@@ -5689,9 +5694,13 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 					[],
 				);
 			}
+
+			$types = $classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds());
 			return new GenericObjectType(
 				$resolvedClassName,
-				$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
+				$types,
+				null,
+				$classReflection->withTypes($types)->asFinal(),
 			);
 		}
 
@@ -5706,9 +5715,12 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 					);
 				}
 
+				$types = $classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds());
 				return new GenericObjectType(
 					$resolvedClassName,
-					$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
+					$types,
+					null,
+					$classReflection->withTypes($types)->asFinal(),
 				);
 			}
 			$newType = new GenericObjectType($resolvedClassName, $classReflection->typeMapToList($classReflection->getTemplateTypeMap()));
@@ -5723,9 +5735,12 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 					);
 				}
 
+				$types = $classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds());
 				return new GenericObjectType(
 					$resolvedClassName,
-					$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
+					$types,
+					null,
+					$classReflection->withTypes($types)->asFinal(),
 				);
 			}
 			$ancestorClassReflections = $ancestorType->getObjectClassReflections();
@@ -5739,9 +5754,12 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 					);
 				}
 
+				$types = $classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds());
 				return new GenericObjectType(
 					$resolvedClassName,
-					$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
+					$types,
+					null,
+					$classReflection->withTypes($types)->asFinal(),
 				);
 			}
 
@@ -5758,9 +5776,12 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 					);
 				}
 
+				$types = $classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds());
 				return new GenericObjectType(
 					$resolvedClassName,
-					$classReflection->typeMapToList($classReflection->getTemplateTypeMap()->resolveToBounds()),
+					$types,
+					null,
+					$classReflection->withTypes($types)->asFinal(),
 				);
 			}
 			$newParentTypeClassReflection = $newParentTypeClassReflections[0];
@@ -5803,9 +5824,12 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 				);
 			}
 
+			$types = $classReflection->typeMapToList(new TemplateTypeMap($resolvedTypeMap));
 			return new GenericObjectType(
 				$resolvedClassName,
-				$classReflection->typeMapToList(new TemplateTypeMap($resolvedTypeMap)),
+				$types,
+				null,
+				$classReflection->withTypes($types)->asFinal(),
 			);
 		}
 
@@ -5817,14 +5841,17 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 		);
 
 		$resolvedTemplateTypeMap = $parametersAcceptor->getResolvedTemplateTypeMap();
+		$types = $classReflection->typeMapToList($classReflection->getTemplateTypeMap());
 		$newGenericType = new GenericObjectType(
 			$resolvedClassName,
-			$classReflection->typeMapToList($classReflection->getTemplateTypeMap()),
+			$types,
+			null,
+			$classReflection->withTypes($types)->asFinal(),
 		);
 		if ($isStatic) {
 			$newGenericType = new GenericStaticType(
 				$classReflection,
-				$classReflection->typeMapToList($classReflection->getTemplateTypeMap()),
+				$types,
 				null,
 				[],
 			);

src/Reflection/ClassReflection.php

@@ -175,6 +175,7 @@ public function __construct(
 		private array $universalObjectCratesClasses,
 		private ?string $extraCacheKey = null,
 		private ?TemplateTypeVarianceMap $resolvedCallSiteVarianceMap = null,
+		private ?bool $finalByKeywordOverride = null,
 	)
 	{
 	}
@@ -306,6 +307,10 @@ public function getCacheKey(): string
 			$cacheKey .= '<' . implode(',', $templateTypes) . '>';
 		}
 
+		if ($this->hasFinalByKeywordOverride()) {
+			$cacheKey .= '-f=' . ($this->isFinalByKeyword() ? 't' : 'f');
+		}
+
 		if ($this->extraCacheKey !== null) {
 			$cacheKey .= '-' . $this->extraCacheKey;
 		}
@@ -1276,12 +1281,21 @@ public function acceptsNamedArguments(): bool
 		return $this->acceptsNamedArguments;
 	}
 
+	public function hasFinalByKeywordOverride(): bool
+	{
+		return $this->isClass() && $this->finalByKeywordOverride !== null;
+	}
+
 	public function isFinalByKeyword(): bool
 	{
 		if ($this->isAnonymous()) {
 			return true;
 		}
 
+		if ($this->isClass() && $this->finalByKeywordOverride !== null) {
+			return $this->finalByKeywordOverride;
+		}
+
 		return $this->reflection->isFinal();
 	}
 
@@ -1543,6 +1557,7 @@ public function withTypes(array $types): self
 			$this->universalObjectCratesClasses,
 			null,
 			$this->resolvedCallSiteVarianceMap,
+			$this->finalByKeywordOverride,
 		);
 	}
 
@@ -1573,6 +1588,42 @@ public function withVariances(array $variances): self
 			$this->universalObjectCratesClasses,
 			null,
 			$this->varianceMapFromList($variances),
+			$this->finalByKeywordOverride,
+		);
+	}
+
+	public function asFinal(): self
+	{
+		if ($this->getNativeReflection()->isFinal()) {
+			return $this;
+		}
+		if ($this->finalByKeywordOverride === true) {
+			return $this;
+		}
+
+		return new self(
+			$this->reflectionProvider,
+			$this->initializerExprTypeResolver,
+			$this->fileTypeMapper,
+			$this->stubPhpDocProvider,
+			$this->phpDocInheritanceResolver,
+			$this->phpVersion,
+			$this->signatureMapProvider,
+			$this->attributeReflectionFactory,
+			$this->propertiesClassReflectionExtensions,
+			$this->methodsClassReflectionExtensions,
+			$this->allowedSubTypesClassReflectionExtensions,
+			$this->requireExtendsPropertiesClassReflectionExtension,
+			$this->requireExtendsMethodsClassReflectionExtension,
+			$this->displayName,
+			$this->reflection,
+			$this->anonymousFilename,
+			$this->resolvedTemplateTypeMap,
+			$this->stubPhpDocBlock,
+			$this->universalObjectCratesClasses,
+			null,
+			$this->resolvedCallSiteVarianceMap,
+			true,
 		);
 	}
 

src/Type/Constant/ConstantStringType.php

@@ -223,7 +223,7 @@ public function isCallable(): TrinaryLogic
 				return TrinaryLogic::createYes();
 			}
 
-			if (!$classRef->getNativeReflection()->isFinal()) {
+			if (!$classRef->isFinalByKeyword()) {
 				return TrinaryLogic::createMaybe();
 			}
 
@@ -265,7 +265,7 @@ public function getCallableParametersAcceptors(ClassMemberAccessAnswerer $scope)
 				return FunctionCallableVariant::createFromVariants($method, $method->getVariants());
 			}
 
-			if (!$classReflection->getNativeReflection()->isFinal()) {
+			if (!$classReflection->isFinalByKeyword()) {
 				return [new TrivialParametersAcceptor()];
 			}
 		}

src/Type/ObjectType.php

@@ -377,21 +377,37 @@ public function isSuperTypeOf(Type $type): IsSuperTypeOfResult
 			throw new ShouldNotHappenException();
 		}
 
-		if ($thatClassNames[0] === $thisClassName) {
-			return $transformResult(IsSuperTypeOfResult::createYes());
-		}
-
-		$reflectionProvider = ReflectionProviderStaticAccessor::getInstance();
 		$thisClassReflection = $this->getClassReflection();
+		$thatClassReflections = $type->getObjectClassReflections();
+		if (count($thatClassReflections) === 1) {
+			$thatClassReflection = $thatClassReflections[0];
+		} else {
+			$thatClassReflection = null;
+		}
 
-		if ($thisClassReflection === null || !$reflectionProvider->hasClass($thatClassNames[0])) {
+		if ($thisClassReflection === null || $thatClassReflection === null) {
+			if ($thatClassNames[0] === $thisClassName) {
+				return self::$superTypes[$thisDescription][$description] = $transformResult(IsSuperTypeOfResult::createYes());
+			}
 			return self::$superTypes[$thisDescription][$description] = IsSuperTypeOfResult::createMaybe();
 		}
 
-		$thatClassReflection = $reflectionProvider->getClass($thatClassNames[0]);
+		if ($thatClassNames[0] === $thisClassName) {
+			if ($thisClassReflection->getNativeReflection()->isFinal()) {
+				return self::$superTypes[$thisDescription][$description] = $transformResult(IsSuperTypeOfResult::createYes());
+			}
+
+			if ($thisClassReflection->hasFinalByKeywordOverride()) {
+				if (!$thatClassReflection->hasFinalByKeywordOverride()) {
+					return self::$superTypes[$thisDescription][$description] = $transformResult(IsSuperTypeOfResult::createMaybe());
+				}
+			}
+
+			return self::$superTypes[$thisDescription][$description] = $transformResult(IsSuperTypeOfResult::createYes());
+		}
 
 		if ($thisClassReflection->isTrait() || $thatClassReflection->isTrait()) {
-			return IsSuperTypeOfResult::createNo();
+			return self::$superTypes[$thisDescription][$description] = IsSuperTypeOfResult::createNo();
 		}
 
 		if ($thisClassReflection->getName() === $thatClassReflection->getName()) {
@@ -406,11 +422,11 @@ public function isSuperTypeOf(Type $type): IsSuperTypeOfResult
 			return self::$superTypes[$thisDescription][$description] = IsSuperTypeOfResult::createMaybe();
 		}
 
-		if ($thisClassReflection->isInterface() && !$thatClassReflection->getNativeReflection()->isFinal()) {
+		if ($thisClassReflection->isInterface() && !$thatClassReflection->isFinalByKeyword()) {
 			return self::$superTypes[$thisDescription][$description] = IsSuperTypeOfResult::createMaybe();
 		}
 
-		if ($thatClassReflection->isInterface() && !$thisClassReflection->getNativeReflection()->isFinal()) {
+		if ($thatClassReflection->isInterface() && !$thisClassReflection->isFinalByKeyword()) {
 			return self::$superTypes[$thisDescription][$description] = IsSuperTypeOfResult::createMaybe();
 		}
 
@@ -550,6 +566,10 @@ private function describeCache(): string
 			$description .= '-';
 			$description .= (string) $reflection->getNativeReflection()->getStartLine();
 			$description .= '-';
+
+			if ($reflection->hasFinalByKeywordOverride()) {
+				$description .= 'f=' . ($reflection->isFinalByKeyword() ? 't' : 'f');
+			}
 		}
 
 		return $this->cachedDescription = $description;
@@ -1331,7 +1351,7 @@ private function findCallableParametersAcceptors(): ?array
 			);
 		}
 
-		if (!$classReflection->getNativeReflection()->isFinal()) {
+		if (!$classReflection->isFinalByKeyword()) {
 			return [new TrivialParametersAcceptor()];
 		}
 

tests/PHPStan/Analyser/nsrt/get-debug-type.php

@@ -33,7 +33,7 @@ function doFoo(bool $b, int $i, float $f, $d, $r, string $s, array $a, $intOrStr
 	assertType("'float'", get_debug_type($d));
 	assertType("'string'", get_debug_type($s));
 	assertType("'array'", get_debug_type($a));
-	assertType("string", get_debug_type($o));
+	assertType("'stdClass'", get_debug_type($o));
 	assertType("string", get_debug_type($std));
 	assertType("'GetDebugType\\\\A'", get_debug_type($A));
 	assertType("string", get_debug_type($r));

tests/PHPStan/Rules/Classes/ImpossibleInstanceOfRuleTest.php

@@ -504,4 +504,15 @@ public function testBug3632(): void
 		]);
 	}
 
+	public function testNewIsAlwaysFinalClass(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/impossible-instanceof-new-is-always-final.php'], [
+			[
+				'Instanceof between ImpossibleInstanceofNewIsAlwaysFinal\Bar and ImpossibleInstanceofNewIsAlwaysFinal\Foo will always evaluate to false.',
+				17,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Classes/data/impossible-instanceof-new-is-always-final.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace ImpossibleInstanceofNewIsAlwaysFinal;
+
+interface Foo
+{
+
+}
+
+class Bar
+{
+
+}
+
+function (): void {
+	$bar = new Bar();
+	if ($bar instanceof Foo) {
+
+	}
+};
+
+function (Bar $bar): void {
+	if ($bar instanceof Foo) {
+
+	}
+};

tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php

@@ -92,6 +92,10 @@ public function testImpossibleCheckTypeFunctionCall(): void
 					'Call to function is_string() with string will always evaluate to true.',
 					140,
 				],
+				[
+					'Call to function method_exists() with CheckTypeFunctionCall\Foo and \'test\' will always evaluate to false.',
+					176,
+				],
 				[
 					'Call to function method_exists() with CheckTypeFunctionCall\Foo and \'doFoo\' will always evaluate to true.',
 					179,
@@ -172,6 +176,10 @@ public function testImpossibleCheckTypeFunctionCall(): void
 					'Call to function method_exists() with CheckTypeFunctionCall\MethodExists and \'testWithNewObjectIn…\' will always evaluate to true.',
 					620,
 				],
+				[
+					'Call to function method_exists() with CheckTypeFunctionCall\MethodExists and \'undefinedMethod\' will always evaluate to false.',
+					623,
+				],
 				[
 					'Call to function method_exists() with CheckTypeFunctionCall\MethodExists and \'testWithNewObjectIn…\' will always evaluate to true.',
 					635,