Keep list on unset() with nested dim-fetch

Author: staabm

src/Type/Accessory/AccessoryArrayListType.php

@@ -160,6 +160,13 @@ public function setExistingOffsetValueType(Type $offsetType, Type $valueType): T
 			return $this;
 		}
 
+		if (
+			$valueType->isArray()->yes()
+			&& IntegerRangeType::fromInterval(0, null)->isSuperTypeOf($offsetType)->yes()
+		) {
+			return $this;
+		}
+
 		return new ErrorType();
 	}
 

tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -1224,6 +1224,11 @@ public function testBug1O580(): void
 	}
 
 	#[RequiresPhp('>= 8.0')]
+	public function testBug12927(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-12927.php'], []);
+	}
+
 	public function testBug4443(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-4443.php'], [

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

@@ -0,0 +1,18 @@
+<?php
+
+namespace Bug12927;
+
+class HelloWorld
+{
+	/**
+	 * @param list<array{abc: string}> $list
+	 * @return list<array<string>>
+	 */
+	public function sayHello(array $list): array
+	{
+		foreach($list as $k => $v) {
+			unset($list[$k]['abc']);
+		}
+		return $list;
+	}
+}

tests/PHPStan/Rules/Variables/ParameterOutAssignedTypeRuleTest.php

@@ -43,7 +43,7 @@ public function testRule(): void
 				47,
 			],
 			[
-				'Parameter &$p @param-out type of method ParameterOutAssignedType\Foo::doBaz3() expects list<list<int>>, array<int<0, max>, array<int<0, max>, int>> given.',
+				'Parameter &$p @param-out type of method ParameterOutAssignedType\Foo::doBaz3() expects list<list<int>>, list<array<int<0, max>, int>> given.',
 				56,
 			],
 			[