Fix unused private property is not sometimes detected

Author: staabm

src/Rules/DeadCode/UnusedPrivateMethodRule.php

@@ -84,7 +84,16 @@ public function processNode(Node $node, Scope $scope): array
 				$methodNameType = $callScope->getType($methodCallNode->name);
 				$strings = $methodNameType->getConstantStrings();
 				if (count($strings) === 0) {
-					return [];
+					// handle subtractions of a dynamic method call
+					foreach ($methods as $lowerMethodName => $method) {
+						if ((new ConstantStringType($method->getNode()->name->toString()))->isSuperTypeOf($methodNameType)->no()) {
+							continue;
+						}
+
+						unset($methods[$lowerMethodName]);
+					}
+
+					continue;
 				}
 
 				$methodNames = array_map(static fn (ConstantStringType $type): string => $type->getValue(), $strings);

src/Rules/DeadCode/UnusedPrivatePropertyRule.php

@@ -120,7 +120,16 @@ public function processNode(Node $node, Scope $scope): array
 				$propertyNameType = $usage->getScope()->getType($fetch->name);
 				$strings = $propertyNameType->getConstantStrings();
 				if (count($strings) === 0) {
-					return [];
+					// handle subtractions of a dynamic property fetch
+					foreach ($properties as $propertyName => $data) {
+						if ((new ConstantStringType($propertyName))->isSuperTypeOf($propertyNameType)->no()) {
+							continue;
+						}
+
+						unset($properties[$propertyName]);
+					}
+
+					continue;
 				}
 
 				$propertyNames = array_map(static fn (ConstantStringType $type): string => $type->getValue(), $strings);

tests/PHPStan/Rules/DeadCode/UnusedPrivateMethodRuleTest.php

@@ -133,4 +133,14 @@ public function testBug9765(): void
 		$this->analyse([__DIR__ . '/data/bug-9765.php'], []);
 	}
 
+	public function testBug11802(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-11802b.php'], [
+			[
+				'Method Bug11802b\HelloWorld::doBar() is unused.',
+				10,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/DeadCode/UnusedPrivatePropertyRuleTest.php

@@ -336,4 +336,19 @@ public function testBug7251(): void
 		$this->analyse([__DIR__ . '/data/bug-7251.php'], []);
 	}
 
+	public function testBug11802(): void
+	{
+		$tip = 'See: https://phpstan.org/developing-extensions/always-read-written-properties';
+
+		$this->alwaysWrittenTags = [];
+		$this->alwaysReadTags = [];
+		$this->analyse([__DIR__ . '/data/bug-11802.php'], [
+			[
+				'Property Bug11802\HelloWorld::$isFinal is never read, only written.',
+				8,
+				$tip,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/DeadCode/data/bug-11802.php

@@ -0,0 +1,20 @@
+<?php // lint >= 8.0
+
+namespace Bug11802;
+
+class HelloWorld
+{
+	public function __construct(
+		private bool $isFinal,
+		private bool $used
+	)
+	{
+	}
+
+	public function doFoo(HelloWorld $x, $y): void
+	{
+		if ($y !== 'isFinal') {
+			$s = $x->{$y};
+		}
+	}
+}

tests/PHPStan/Rules/DeadCode/data/bug-11802b.php

@@ -0,0 +1,19 @@
+<?php // lint >= 8.0
+
+namespace Bug11802b;
+
+class HelloWorld
+{
+	public function __construct(
+	) {}
+
+	private function doBar():void {}
+
+	private function doFooBar():void {}
+
+	public function doFoo(HelloWorld $x, $y): void {
+		if ($y !== 'doBar') {
+			$s = $x->$y();
+		}
+	}
+}