From 5ad91d26e2f411505e932ecdc5a412d797c2b817 Mon Sep 17 00:00:00 2001
From: Ondrej Mirtes <ondrej@mirtes.cz>
Date: Mon, 1 Feb 2021 11:26:28 +0100
Subject: [PATCH] Do not complain about interface and abstract class when
 instantiating from object

---
 src/Rules/Classes/InstantiationRule.php       | 31 ++++++++++++-------
 .../Rules/Classes/InstantiationRuleTest.php   | 19 ++++++++++++
 tests/PHPStan/Rules/Classes/data/bug-4471.php | 28 +++++++++++++++++
 3 files changed, 67 insertions(+), 11 deletions(-)
 create mode 100644 tests/PHPStan/Rules/Classes/data/bug-4471.php

diff --git a/src/Rules/Classes/InstantiationRule.php b/src/Rules/Classes/InstantiationRule.php
index bb12d889ed..17b4413331 100644
--- a/src/Rules/Classes/InstantiationRule.php
+++ b/src/Rules/Classes/InstantiationRule.php
@@ -48,8 +48,8 @@ public function getNodeType(): string
 	public function processNode(Node $node, Scope $scope): array
 	{
 		$errors = [];
-		foreach ($this->getClassNames($node, $scope) as $class) {
-			$errors = array_merge($errors, $this->checkClassName($class, $node, $scope));
+		foreach ($this->getClassNames($node, $scope) as [$class, $isName]) {
+			$errors = array_merge($errors, $this->checkClassName($class, $isName, $node, $scope));
 		}
 		return $errors;
 	}
@@ -60,7 +60,7 @@ public function processNode(Node $node, Scope $scope): array
 	 * @param Scope $scope
 	 * @return RuleError[]
 	 */
-	private function checkClassName(string $class, Node $node, Scope $scope): array
+	private function checkClassName(string $class, bool $isName, Node $node, Scope $scope): array
 	{
 		$lowercasedClass = strtolower($class);
 		$messages = [];
@@ -131,7 +131,7 @@ private function checkClassName(string $class, Node $node, Scope $scope): array
 			$classReflection = $this->reflectionProvider->getClass($class);
 		}
 
-		if (!$isStatic && $classReflection->isInterface()) {
+		if (!$isStatic && $classReflection->isInterface() && $isName) {
 			return [
 				RuleErrorBuilder::message(
 					sprintf('Cannot instantiate interface %s.', $classReflection->getDisplayName())
@@ -139,7 +139,7 @@ private function checkClassName(string $class, Node $node, Scope $scope): array
 			];
 		}
 
-		if (!$isStatic && $classReflection->isAbstract()) {
+		if (!$isStatic && $classReflection->isAbstract() && $isName) {
 			return [
 				RuleErrorBuilder::message(
 					sprintf('Instantiated class %s is abstract.', $classReflection->getDisplayName())
@@ -147,6 +147,10 @@ private function checkClassName(string $class, Node $node, Scope $scope): array
 			];
 		}
 
+		if (!$isName) {
+			return [];
+		}
+
 		if (!$classReflection->hasConstructor()) {
 			if (count($node->args) > 0) {
 				return array_merge($messages, [
@@ -200,12 +204,12 @@ private function checkClassName(string $class, Node $node, Scope $scope): array
 	/**
 	 * @param \PhpParser\Node\Expr\New_ $node $node
 	 * @param Scope $scope
-	 * @return string[]
+	 * @return array<int, array{string, bool}>
 	 */
 	private function getClassNames(Node $node, Scope $scope): array
 	{
 		if ($node->class instanceof \PhpParser\Node\Name) {
-			return [(string) $node->class];
+			return [[(string) $node->class, true]];
 		}
 
 		if ($node->class instanceof Node\Stmt\Class_) {
@@ -214,19 +218,24 @@ private function getClassNames(Node $node, Scope $scope): array
 				throw new \PHPStan\ShouldNotHappenException();
 			}
 
-			return [$anonymousClassType->getClassName()];
+			return [[$anonymousClassType->getClassName(), true]];
 		}
 
 		$type = $scope->getType($node->class);
 
 		return array_merge(
 			array_map(
-				static function (ConstantStringType $type): string {
-					return $type->getValue();
+				static function (ConstantStringType $type): array {
+					return [$type->getValue(), true];
 				},
 				TypeUtils::getConstantStrings($type)
 			),
-			TypeUtils::getDirectClassNames($type)
+			array_map(
+				static function (string $name): array {
+					return [$name, false];
+				},
+				TypeUtils::getDirectClassNames($type)
+			)
 		);
 	}
 
diff --git a/tests/PHPStan/Rules/Classes/InstantiationRuleTest.php b/tests/PHPStan/Rules/Classes/InstantiationRuleTest.php
index 62bf98915b..5b6a2eb059 100644
--- a/tests/PHPStan/Rules/Classes/InstantiationRuleTest.php
+++ b/tests/PHPStan/Rules/Classes/InstantiationRuleTest.php
@@ -312,4 +312,23 @@ public function testNamedArguments(): void
 		]);
 	}
 
+	public function testBug4471(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-4471.php'], [
+			[
+				'Instantiated class Bug4471\Baz not found.',
+				19,
+				'Learn more at https://phpstan.org/user-guide/discovering-symbols',
+			],
+			[
+				'Instantiated class Bug4471\Foo is abstract.',
+				24,
+			],
+			[
+				'Cannot instantiate interface Bug4471\Bar.',
+				27,
+			],
+		]);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Classes/data/bug-4471.php b/tests/PHPStan/Rules/Classes/data/bug-4471.php
new file mode 100644
index 0000000000..46818e2ad7
--- /dev/null
+++ b/tests/PHPStan/Rules/Classes/data/bug-4471.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace Bug4471;
+
+abstract class Foo
+{
+
+}
+
+interface Bar
+{
+
+}
+
+function (Foo $foo, Bar $bar, Baz $baz): void {
+	new $foo;
+	new $bar;
+	new $foo(1);
+	new $baz;
+};
+
+function (): void {
+	$foo = Foo::class;
+	new $foo;
+
+	$bar = Bar::class;
+	new $bar;
+};