Do not report undefined property in isset/empty/?? for types without class names

When checkDynamicProperties is enabled, PHPStan incorrectly reported
"Access to an undefined property" for chained isset() checks on mixed
types. After the first isset() narrows mixed to object&hasProperty(foo),
the second isset($tmp->bar) was being flagged because pickProperty
returned null for the intersection type that has no concrete class names.

The fix skips the dynamic property check when the type has no class names
(bare object or object&hasProperty), since we cannot know what properties
such a type might have.

Closes phpstan/phpstan#13539

Author: VincentLanglet

src/Rules/Properties/AccessPropertiesCheck.php

@@ -140,6 +140,10 @@ private function processSingleProperty(Scope $scope, PropertyFetch $node, string
 					return [];
 				}
 
+				if (count($type->getObjectClassNames()) === 0) {
+					return [];
+				}
+
 				$maybePropertyReflection = $this->pickProperty($scope, $type, $name);
 				if ($maybePropertyReflection !== null && $maybePropertyReflection->isDummy()->no()) {
 					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 +1272,13 @@ 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'], []);
+	}
+
 }

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

@@ -0,0 +1,56 @@
+<?php
+
+namespace Bug13539;
+
+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)) {
+    }
+}
+
+function threeProperties(string $x): void {
+	$tmp = json_decode($x, false);
+
+	if (!isset($tmp->foo) || !isset($tmp->bar) || !isset($tmp->baz)) {
+    }
+}
+
+function coalesceAfterIsset(string $x): void {
+	$tmp = json_decode($x, false);
+
+	if (isset($tmp->foo)) {
+		$bar = $tmp->bar ?? null;
+	}
+}
+
+function issetInAndChain(string $x): void {
+	$tmp = json_decode($x, false);
+
+	if (isset($tmp->foo) && isset($tmp->bar)) {
+    }
+}
+
+function emptyAfterIsset(string $x): void {
+	$tmp = json_decode($x, false);
+
+	if (isset($tmp->foo)) {
+		if (empty($tmp->bar)) {
+		}
+	}
+}