added type assertions

Author: staabm

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -211,6 +211,7 @@ private static function findTestFiles(): iterable
 		yield __DIR__ . '/../Rules/Arrays/data/bug-11679.php';
 		yield __DIR__ . '/../Rules/Methods/data/bug-4801.php';
 		yield __DIR__ . '/../Rules/Arrays/data/narrow-superglobal.php';
+		yield __DIR__ . '/../Rules/Methods/data/bug-12927.php';
 	}
 
 	/**

tests/PHPStan/Rules/Methods/data/bug-12927.php

@@ -2,6 +2,8 @@
 
 namespace Bug12927;
 
+use function PHPStan\Testing\assertType;
+
 class HelloWorld
 {
 	/**
@@ -12,6 +14,22 @@ public function sayHello(array $list): array
 	{
 		foreach($list as $k => $v) {
 			unset($list[$k]['abc']);
+			assertType('non-empty-list<array{}|array{abc: string}>', $list);
+			assertType('array{}|array{abc: string}', $list[$k]);
+		}
+		return $list;
+	}
+
+	/**
+	 * @param list<array<string, string>> $list
+	 * @return list<array<string>>
+	 */
+	public function sayFoo(array $list): array
+	{
+		foreach($list as $k => $v) {
+			unset($list[$k]['abc']);
+			assertType('non-empty-list<array<string, string>>', $list);
+			assertType('array<string, string>', $list[$k]);
 		}
 		return $list;
 	}