Assignment to property in closure is an impure point

src/Analyser/MutatingScope.php

@@ -44,6 +44,7 @@
 use PHPStan\Node\InvalidateExprNode;
 use PHPStan\Node\IssetExpr;
 use PHPStan\Node\Printer\ExprPrinter;
+use PHPStan\Node\PropertyAssignNode;
 use PHPStan\Parser\ArrayMapArgVisitor;
 use PHPStan\Parser\NewAssignedToPropertyVisitor;
 use PHPStan\Parser\Parser;
@@ -1287,8 +1288,9 @@ static function (): void {
 				$closureReturnStatements = [];
 				$closureYieldStatements = [];
 				$closureExecutionEnds = [];
+				$closureImpurePoints = [];
 				$invalidateExpressions = [];
-				$closureStatementResult = $this->nodeScopeResolver->processStmtNodes($node, $node->stmts, $closureScope, static function (Node $node, Scope $scope) use ($closureScope, &$closureReturnStatements, &$closureYieldStatements, &$closureExecutionEnds, &$invalidateExpressions): void {
+				$closureStatementResult = $this->nodeScopeResolver->processStmtNodes($node, $node->stmts, $closureScope, static function (Node $node, Scope $scope) use ($closureScope, &$closureReturnStatements, &$closureYieldStatements, &$closureExecutionEnds, &$closureImpurePoints, &$invalidateExpressions): void {
 					if ($scope->getAnonymousFunctionReflection() !== $closureScope->getAnonymousFunctionReflection()) {
 						return;
 					}
@@ -1298,6 +1300,17 @@ static function (): void {
 						return;
 					}
 
+					if ($node instanceof PropertyAssignNode) {
+						$closureImpurePoints[] = new ImpurePoint(
+							$scope,
+							$node,
+							'propertyAssign',
+							'property assignment',
+							true,
+						);
+						return;
+					}
+
 					if ($node instanceof ExecutionEndNode) {
 						if ($node->getStatementResult()->isAlwaysTerminating()) {
 							foreach ($node->getStatementResult()->getExitPoints() as $exitPoint) {
@@ -1329,7 +1342,7 @@ static function (): void {
 				}, StatementContext::createTopLevel());
 
 				$throwPoints = $closureStatementResult->getThrowPoints();
-				$impurePoints = $closureStatementResult->getImpurePoints();
+				$impurePoints = array_merge($closureImpurePoints, $closureStatementResult->getImpurePoints());
 
 				$returnTypes = [];
 				$hasNull = false;

tests/PHPStan/Rules/DeadCode/BetterNoopRuleTest.php

@@ -126,11 +126,11 @@ public function testRuleImpurePoints(): void
 		$this->analyse([__DIR__ . '/data/noop-impure-points.php'], [
 			[
 				'Unused result of "&&" operator.',
-				10,
+				12,
 			],
 			[
 				'Expression "$b()" on a separate line does not do anything.',
-				57,
+				59,
 			],
 		]);
 	}

tests/PHPStan/Rules/DeadCode/data/noop-impure-points.php

@@ -5,6 +5,8 @@
 class Foo
 {
 
+	private static $staticProp = 1;
+
 	public function doFoo(bool $b): void
 	{
 		$b && $this->doBar();
@@ -61,6 +63,16 @@ public function doClosures(): void
 			$ref++;
 		};
 		$c();
+
+		$d = function () {
+			self::$foo = 1;
+		};
+		$d();
+
+		$e = function () {
+			self::$staticProp = 1;
+		};
+		$e();
 	}
 
 }