Fix phpstan/phpstan#13539: property.notFound in chained isset() with checkDynamicProperties

src/Rules/Properties/AccessPropertiesCheck.php

@@ -144,6 +144,10 @@ private function processSingleProperty(Scope $scope, PropertyFetch $node, string
 				if ($maybePropertyReflection !== null && $maybePropertyReflection->isDummy()->no()) {
 					return [];
 				}
+
+				if ($type->getObjectClassNames() === []) {
+					return [];
+				}
 			}
 		}
 

tests/PHPStan/Analyser/AnalyserWithCheckDynamicPropertiesTest.php

@@ -12,9 +12,7 @@ class AnalyserWithCheckDynamicPropertiesTest extends PHPStanTestCase
 	public function testBug13529(): void
 	{
 		$errors = $this->runAnalyse(__DIR__ . '/data/bug-13529.php');
-		$this->assertCount(1, $errors);
-		$this->assertSame('Access to an undefined property object::$bar.', $errors[0]->getMessage());
-		$this->assertSame(8, $errors[0]->getLine());
+		$this->assertCount(0, $errors);
 	}
 
 	/**

tests/PHPStan/Rules/Properties/AccessPropertiesRuleTest.php

@@ -1272,4 +1272,18 @@ public function testBug13537(): void
 		$this->analyse([__DIR__ . '/data/bug-13537.php'], $errors);
 	}
 
+	public function testBug13539(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkUnionTypes = true;
+		$this->checkDynamicProperties = true;
+		$this->analyse([__DIR__ . '/data/bug-13539.php'], [
+			[
+				'Access to an undefined property object::$baz.',
+				29,
+				'Learn more: <fg=cyan>https://phpstan.org/blog/solving-phpstan-access-to-undefined-property</>',
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Properties/data/bug-13539.php

@@ -0,0 +1,31 @@
+<?php
+
+function broken(string $x): void {
+	$tmp = json_decode($x, false);
+	if (!isset($tmp->foo) || !isset($tmp->bar)) {
+	}
+}
+
+function works(string $x): void {
+	$tmp = json_decode($x, false);
+	if (!isset($tmp->foo, $tmp->bar)) {
+	}
+}
+
+function works_too(string $x): void {
+	/** @var stdClass $tmp */
+	$tmp = json_decode($x, false);
+	if (!isset($tmp->foo) || !isset($tmp->bar)) {
+	}
+}
+
+/**
+ * @param mixed $tmp
+ */
+function also_ok($tmp): void {
+	if (isset($tmp->foo) && isset($tmp->bar)) {
+		echo $tmp->foo;
+		echo $tmp->bar;
+		echo $tmp->baz; // intentional: baz not checked by isset
+	}
+}