Add regression test

Author: staabm

tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php

@@ -829,4 +829,11 @@ public function testArrayDimFetchAfterArraySearch(): void
 		]);
 	}
 
+	public function testBug8649(): void
+	{
+		$this->reportPossiblyNonexistentGeneralArrayOffset = true;
+
+		$this->analyse([__DIR__ . '/data/bug-8649.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Arrays/data/bug-8649.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Bug8649;
+
+class HelloWorld
+{
+	public function test(): void
+	{
+		/** @var array{array{a: ?string}, array{b: ?string},} $test */
+		$test = [
+			['a' => 'test'],
+			['b' => 'asdf'],
+		];
+
+		foreach ($test as $property) {
+			$firstKey = array_key_first($property);
+
+			if ($firstKey === 'b') {
+				continue;
+			}
+
+			echo($property[$firstKey]);
+		}
+	}
+}