Bleeding edge - intersect array key type with int|string

conf/config.neon

@@ -404,6 +404,8 @@ services:
 
 	-
 		class: PHPStan\PhpDoc\TypeNodeResolver
+		arguments:
+			deepInspectTypes: %featureToggles.deepInspectTypes%
 
 	-
 		class: PHPStan\PhpDoc\TypeNodeResolverExtensionRegistryProvider

src/PhpDoc/TypeNodeResolver.php

@@ -73,13 +73,17 @@ class TypeNodeResolver
 
 	private Container $container;
 
+	private bool $deepInspectTypes;
+
 	public function __construct(
 		TypeNodeResolverExtensionRegistryProvider $extensionRegistryProvider,
-		Container $container
+		Container $container,
+		bool $deepInspectTypes = false
 	)
 	{
 		$this->extensionRegistryProvider = $extensionRegistryProvider;
 		$this->container = $container;
+		$this->deepInspectTypes = $deepInspectTypes;
 	}
 
 	/** @api */
@@ -417,7 +421,14 @@ private function resolveGenericTypeNode(GenericTypeNode $typeNode, NameScope $na
 			if (count($genericTypes) === 1) { // array<ValueType>
 				$arrayType = new ArrayType(new MixedType(true), $genericTypes[0]);
 			} elseif (count($genericTypes) === 2) { // array<KeyType, ValueType>
-				$arrayType = new ArrayType($genericTypes[0], $genericTypes[1]);
+				$keyType = $genericTypes[0];
+				if ($this->deepInspectTypes) {
+					$keyType = TypeCombinator::intersect($keyType, new UnionType([
+						new IntegerType(),
+						new StringType(),
+					]));
+				}
+				$arrayType = new ArrayType($keyType, $genericTypes[1]);
 			} else {
 				return new ErrorType();
 			}

tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php

@@ -86,7 +86,12 @@ public function testIsGenerator(): void
 	public function testBug2568(): void
 	{
 		require_once __DIR__ . '/data/bug-2568.php';
-		$this->analyse([__DIR__ . '/data/bug-2568.php'], []);
+		$this->analyse([__DIR__ . '/data/bug-2568.php'], [
+			[
+				'Function Bug2568\my_array_keys() should return array<int, T> but returns array<int, (int&T)|(string&T)>.',
+				12,
+			],
+		]);
 	}
 
 	public function testBug2723(): void

tests/PHPStan/Rules/Functions/data/bug-2568.php

@@ -11,3 +11,23 @@
 function my_array_keys($arr) {
 	return array_keys($arr);
 }
+
+/**
+ * @template T of array-key
+ *
+ * @param array<T, mixed> $arr
+ * @return array<int, T>
+ */
+function my_array_keys2($arr) {
+	return array_keys($arr);
+}
+
+/**
+ * @template T of int|string
+ *
+ * @param array<T, mixed> $arr
+ * @return array<int, T>
+ */
+function my_array_keys3($arr) {
+	return array_keys($arr);
+}

tests/PHPStan/Rules/Methods/data/infer-array-key.php

@@ -22,3 +22,79 @@ public function getIterator()
 	}
 
 }
+
+/**
+ * @implements \IteratorAggregate<int, \stdClass>
+ */
+class Bar implements \IteratorAggregate
+{
+
+	/** @var array<int, \stdClass> */
+	private $items;
+
+	public function getIterator()
+	{
+		$it = new \ArrayIterator($this->items);
+		assertType('int', $it->key());
+
+		return $it;
+	}
+
+}
+
+/**
+ * @implements \IteratorAggregate<string, \stdClass>
+ */
+class Baz implements \IteratorAggregate
+{
+
+	/** @var array<string, \stdClass> */
+	private $items;
+
+	public function getIterator()
+	{
+		$it = new \ArrayIterator($this->items);
+		assertType('string', $it->key());
+
+		return $it;
+	}
+
+}
+
+/**
+ * @implements \IteratorAggregate<int, \stdClass>
+ */
+class Lorem implements \IteratorAggregate
+{
+
+	/** @var array<\stdClass> */
+	private $items;
+
+	public function getIterator()
+	{
+		$it = new \ArrayIterator($this->items);
+		assertType('(int|string)', $it->key());
+
+		return $it;
+	}
+
+}
+
+/**
+ * @implements \IteratorAggregate<int|string, \stdClass>
+ */
+class Ipsum implements \IteratorAggregate
+{
+
+	/** @var array<int|string, \stdClass> */
+	private $items;
+
+	public function getIterator()
+	{
+		$it = new \ArrayIterator($this->items);
+		assertType('int|string', $it->key());
+
+		return $it;
+	}
+
+}

tests/PHPStan/Rules/PhpDoc/IncompatiblePhpDocTypeRuleTest.php

@@ -162,6 +162,10 @@ public function testBug3753(): void
 				'PHPDoc tag @param for parameter $foo contains unresolvable type.',
 				20,
 			],
+			[
+				'PHPDoc tag @param for parameter $bars contains unresolvable type.',
+				28,
+			],
 		]);
 	}
 

tests/PHPStan/Type/TypeCombinatorTest.php

@@ -15,12 +15,14 @@
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\Generic\GenericClassStringType;
 use PHPStan\Type\Generic\GenericObjectType;
+use PHPStan\Type\Generic\TemplateBenevolentUnionType;
 use PHPStan\Type\Generic\TemplateObjectType;
 use PHPStan\Type\Generic\TemplateObjectWithoutClassType;
 use PHPStan\Type\Generic\TemplateType;
 use PHPStan\Type\Generic\TemplateTypeFactory;
 use PHPStan\Type\Generic\TemplateTypeScope;
 use PHPStan\Type\Generic\TemplateTypeVariance;
+use PHPStan\Type\Generic\TemplateUnionType;
 
 class TypeCombinatorTest extends \PHPStan\Testing\TestCase
 {
@@ -2945,6 +2947,45 @@ public function dataIntersect(): array
 				NeverType::class,
 				'*NEVER*',
 			],
+			[
+				[
+					TemplateTypeFactory::create(
+						TemplateTypeScope::createWithFunction('my_array_keys'),
+						'T',
+						new BenevolentUnionType([new IntegerType(), new StringType()]),
+						TemplateTypeVariance::createInvariant(),
+					),
+					new UnionType([new IntegerType(), new StringType()]),
+				],
+				TemplateBenevolentUnionType::class,
+				'T of (int|string) (function my_array_keys(), parameter)',
+			],
+			[
+				[
+					TemplateTypeFactory::create(
+						TemplateTypeScope::createWithFunction('my_array_keys'),
+						'T',
+						new BenevolentUnionType([new IntegerType(), new StringType()]),
+						TemplateTypeVariance::createInvariant(),
+					),
+					new BenevolentUnionType([new IntegerType(), new StringType()]),
+				],
+				TemplateBenevolentUnionType::class,
+				'T of (int|string) (function my_array_keys(), parameter)',
+			],
+			[
+				[
+					TemplateTypeFactory::create(
+						TemplateTypeScope::createWithFunction('my_array_keys'),
+						'T',
+						new UnionType([new IntegerType(), new StringType()]),
+						TemplateTypeVariance::createInvariant(),
+					),
+					new UnionType([new IntegerType(), new StringType()]),
+				],
+				UnionType::class,
+				'T of int|string (function my_array_keys(), parameter)',
+			],
 		];
 	}