Pure cont'd

src/Analyser/NodeScopeResolver.php

@@ -648,6 +648,14 @@ private function processStmtNode(
 						return;
 					}
 					if ($node instanceof PropertyAssignNode) {
+						if (
+							$node->getPropertyFetch() instanceof Expr\PropertyFetch
+							&& $scope->getFunction() instanceof PhpMethodFromParserNodeReflection
+							&& $scope->getFunction()->getDeclaringClass()->hasConstructor()
+							&& $scope->getFunction()->getDeclaringClass()->getConstructor()->getName() === $scope->getFunction()->getName()
+						) {
+							return;
+						}
 						$methodImpurePoints[] = new ImpurePoint(
 							$scope,
 							$node,
@@ -2934,6 +2942,27 @@ static function (): void {
 			$impurePoints[] = new ImpurePoint($scope, $expr, 'print', 'print', true);
 			$hasYield = $result->hasYield();
 
+			$scope = $result->getScope();
+		} elseif ($expr instanceof Cast\String_) {
+			$result = $this->processExprNode($stmt, $expr->expr, $scope, $nodeCallback, $context->enterDeep());
+			$throwPoints = $result->getThrowPoints();
+			$impurePoints = $result->getImpurePoints();
+			$hasYield = $result->hasYield();
+
+			$exprType = $scope->getType($expr->expr);
+			$toStringMethod = $scope->getMethodReflection($exprType, '__toString');
+			if ($toStringMethod !== null) {
+				if (!$toStringMethod->hasSideEffects()->no()) {
+					$impurePoints[] = new ImpurePoint(
+						$scope,
+						$expr,
+						'methodCall',
+						sprintf('call to method %s::%s()', $toStringMethod->getDeclaringClass()->getDisplayName(), $toStringMethod->getName()),
+						$toStringMethod->isPure()->no(),
+					);
+				}
+			}
+
 			$scope = $result->getScope();
 		} elseif (
 			$expr instanceof Expr\BitwiseNot

tests/PHPStan/Rules/Pure/PureMethodRuleTest.php

@@ -4,6 +4,7 @@
 
 use PHPStan\Rules\Rule;
 use PHPStan\Testing\RuleTestCase;
+use const PHP_VERSION_ID;
 
 /**
  * @extends RuleTestCase<PureMethodRule>
@@ -115,6 +116,32 @@ public function testRule(): void
 				'Impure assign to superglobal variable in pure method PureMethod\ClassWithVoidMethods::purePostGetAssign().',
 				231,
 			],
+			[
+				'Possibly impure call to method PureMethod\MaybePureMagicMethods::__toString() in pure method PureMethod\TestMagicMethods::doFoo().',
+				295,
+			],
+			[
+				'Impure call to method PureMethod\ImpureMagicMethods::__toString() in pure method PureMethod\TestMagicMethods::doFoo().',
+				296,
+			],
+		]);
+	}
+
+	public function testPureConstructor(): void
+	{
+		if (PHP_VERSION_ID < 80000) {
+			$this->markTestSkipped('Test requires PHP 8.0.');
+		}
+
+		$this->analyse([__DIR__ . '/data/pure-constructor.php'], [
+			[
+				'Impure property assignment in pure method PureConstructor\Foo::__construct().',
+				19,
+			],
+			[
+				'Method PureConstructor\Bar::__construct() is marked as impure but does not have any side effects.',
+				30,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/Pure/data/pure-constructor.php

@@ -0,0 +1,38 @@
+<?php // lint >= 8.0
+
+namespace PureConstructor;
+
+class Foo
+{
+
+	private string $prop;
+
+	public static $staticProp = 1;
+
+	/** @phpstan-pure */
+	public function __construct(
+		public int $test,
+		string $prop,
+	)
+	{
+		$this->prop = $prop;
+		self::$staticProp++;
+	}
+
+}
+
+class Bar
+{
+
+	private string $prop;
+
+	/** @phpstan-impure */
+	public function __construct(
+		public int $test,
+		string $prop,
+	)
+	{
+		$this->prop = $prop;
+	}
+
+}

tests/PHPStan/Rules/Pure/data/pure-method.php

@@ -234,3 +234,66 @@ public function purePostGetAssign(array $post = [], array $get = []): int
 	}
 
 }
+
+class NoMagicMethods
+{
+
+}
+
+class PureMagicMethods
+{
+
+	/**
+	 * @phpstan-pure
+	 */
+	public function __toString(): string
+	{
+		return 'one';
+	}
+
+}
+
+class MaybePureMagicMethods
+{
+
+	public function __toString(): string
+	{
+		return 'one';
+	}
+
+}
+
+class ImpureMagicMethods
+{
+
+	/**
+	 * @phpstan-impure
+	 */
+	public function __toString(): string
+	{
+		sleep(1);
+		return 'one';
+	}
+
+}
+
+class TestMagicMethods
+{
+
+	/**
+	 * @phpstan-pure
+	 */
+	public function doFoo(
+		NoMagicMethods $no,
+		PureMagicMethods $pure,
+		MaybePureMagicMethods $maybe,
+		ImpureMagicMethods $impure
+	)
+	{
+		(string) $no;
+		(string) $pure;
+		(string) $maybe;
+		(string) $impure;
+	}
+
+}