Add regression test for #12390

Author: predictor2718

tests/PHPStan/Rules/Properties/AccessPropertiesRuleTest.php

@@ -1272,6 +1272,14 @@ public function testBug13537(): void
 		$this->analyse([__DIR__ . '/data/bug-13537.php'], $errors);
 	}
 
+	public function testBug12390(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkUnionTypes = true;
+		$this->checkDynamicProperties = true;
+		$this->analyse([__DIR__ . '/data/bug-12390.php'], []);
+	}
+
 	public function testBug13539(): void
 	{
 		$this->checkThisOnly = false;

tests/PHPStan/Rules/Properties/data/bug-12390.php

@@ -0,0 +1,22 @@
+<?php
+
+function testIssetOnGenericObject(object $obj): void
+{
+	if (isset($obj->foo)) {
+	}
+}
+
+function testChainedIssetOnGenericObject(object $obj): void
+{
+	if (isset($obj->foo) && isset($obj->bar)) {
+	}
+}
+
+function testIssetAfterIsObjectNarrowing(string $date): void
+{
+	if (is_object($obj = json_decode($date))) {
+		if (isset($obj->crashId) && is_string($obj->crashId)) {
+			var_dump($obj->crashId);
+		}
+	}
+}