Object type narrowed after $a::class and get_class($a) cannot be a subclass

Author: ondrejmirtes

Diff for: phpstan-baseline.neon

@@ -75,7 +75,7 @@ parameters:
 		-
 			message: '#^Doing instanceof PHPStan\\Type\\Constant\\ConstantStringType is error\-prone and deprecated\. Use Type\:\:getConstantStrings\(\) instead\.$#'
 			identifier: phpstanApi.instanceofType
-			count: 3
+			count: 4
 			path: src/Analyser/TypeSpecifier.php
 
 		-

Diff for: src/Analyser/TypeSpecifier.php

@@ -2205,6 +2205,14 @@ public function resolveIdentical(Expr\BinaryOp\Identical $expr, Scope $scope, Ty
 			&& in_array(strtolower($unwrappedLeftExpr->name->toString()), ['get_class', 'get_debug_type'], true)
 			&& isset($unwrappedLeftExpr->getArgs()[0])
 		) {
+			if ($rightType instanceof ConstantStringType && $this->reflectionProvider->hasClass($rightType->getValue())) {
+				return $this->create(
+					$unwrappedLeftExpr->getArgs()[0]->value,
+					new ObjectType($rightType->getValue(), null, $this->reflectionProvider->getClass($rightType->getValue())->asFinal()),
+					$context,
+					$scope,
+				)->unionWith($this->create($leftExpr, $rightType, $context, $scope))->setRootExpr($expr);
+			}
 			if ($rightType->getClassStringObjectType()->isObject()->yes()) {
 				return $this->create(
 					$unwrappedLeftExpr->getArgs()[0]->value,
@@ -2215,7 +2223,6 @@ public function resolveIdentical(Expr\BinaryOp\Identical $expr, Scope $scope, Ty
 			}
 		}
 
-		// get_class($a) === 'Foo'
 		if (
 			$context->truthy()
 			&& $unwrappedLeftExpr instanceof FuncCall
@@ -2305,6 +2312,14 @@ public function resolveIdentical(Expr\BinaryOp\Identical $expr, Scope $scope, Ty
 			$rightType->getValue() !== '' &&
 			strtolower($unwrappedLeftExpr->name->toString()) === 'class'
 		) {
+			if ($this->reflectionProvider->hasClass($rightType->getValue())) {
+				return $this->create(
+					$unwrappedLeftExpr->class,
+					new ObjectType($rightType->getValue(), null, $this->reflectionProvider->getClass($rightType->getValue())->asFinal()),
+					$context,
+					$scope,
+				)->unionWith($this->create($leftExpr, $rightType, $context, $scope))->setRootExpr($expr);
+			}
 			return $this->specifyTypesInCondition(
 				$scope,
 				new Instanceof_(
@@ -2328,6 +2343,15 @@ public function resolveIdentical(Expr\BinaryOp\Identical $expr, Scope $scope, Ty
 			$leftType->getValue() !== '' &&
 			strtolower($unwrappedRightExpr->name->toString()) === 'class'
 		) {
+			if ($this->reflectionProvider->hasClass($leftType->getValue())) {
+				return $this->create(
+					$unwrappedRightExpr->class,
+					new ObjectType($leftType->getValue(), null, $this->reflectionProvider->getClass($leftType->getValue())->asFinal()),
+					$context,
+					$scope,
+				)->unionWith($this->create($rightExpr, $leftType, $context, $scope)->setRootExpr($expr));
+			}
+
 			return $this->specifyTypesInCondition(
 				$scope,
 				new Instanceof_(

Diff for: tests/PHPStan/Rules/Classes/ImpossibleInstanceOfRuleTest.php

@@ -506,12 +506,32 @@ public function testBug3632(): void
 
 	public function testNewIsAlwaysFinalClass(): void
 	{
+		if (PHP_VERSION_ID < 80000) {
+			$this->markTestSkipped('This test needs PHP 8.0.');
+		}
+
 		$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,
 			],
+			[
+				'Instanceof between ImpossibleInstanceofNewIsAlwaysFinal\Bar and ImpossibleInstanceofNewIsAlwaysFinal\Foo will always evaluate to false.',
+				33,
+			],
+			[
+				'Instanceof between ImpossibleInstanceofNewIsAlwaysFinal\Bar and ImpossibleInstanceofNewIsAlwaysFinal\Foo will always evaluate to false.',
+				43,
+			],
+			[
+				'Instanceof between ImpossibleInstanceofNewIsAlwaysFinal\Bar and ImpossibleInstanceofNewIsAlwaysFinal\Foo will always evaluate to false.',
+				53,
+			],
+			[
+				'Instanceof between ImpossibleInstanceofNewIsAlwaysFinal\Bar and ImpossibleInstanceofNewIsAlwaysFinal\Foo will always evaluate to false.',
+				63,
+			],
 		]);
 	}
 

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

@@ -1,4 +1,4 @@
-<?php
+<?php // lint >= 8.0
 
 namespace ImpossibleInstanceofNewIsAlwaysFinal;
 
@@ -24,3 +24,43 @@ function (Bar $bar): void {
 
 	}
 };
+
+function (Bar $bar): void {
+	if ($bar::class !== Bar::class) {
+		return;
+	}
+
+	if ($bar instanceof Foo) {
+
+	}
+};
+
+function (Bar $bar): void {
+	if (Bar::class !== $bar::class) {
+		return;
+	}
+
+	if ($bar instanceof Foo) {
+
+	}
+};
+
+function (Bar $bar): void {
+	if (get_class($bar) !== Bar::class) {
+		return;
+	}
+
+	if ($bar instanceof Foo) {
+
+	}
+};
+
+function (Bar $bar): void {
+	if (Bar::class !== get_class($bar)) {
+		return;
+	}
+
+	if ($bar instanceof Foo) {
+
+	}
+};